Astrophysics
New submissions
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New submissions for Mon, 2 Dec 19
- [1] arXiv:1911.12367 [pdf, other]
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Title: The baryon content of groups and clusters of galaxies in the FABLE simulationsComments: 27 pages, 13 figures, 1 appendix; submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We study the gas and stellar mass content of galaxy groups and clusters in the FABLE suite of cosmological hydrodynamical simulations, including the evolution of their central brightest cluster galaxies (BCGs), satellite galaxies and intracluster light (ICL). The total gas and stellar mass of FABLE clusters are in very good agreement with observations and show negligible redshift evolution at fixed halo mass for $M_{500} \gtrsim 3 \times 10^{14} M_{\odot}$ at $z \lesssim 1$, in line with recent findings from Sunyaev-Zel'dovich (SZ)-selected cluster samples. Importantly, the simulations predict significant redshift evolution in these quantities in the low mass ($M_{500} \sim 10^{14} M_{\odot}$) regime, which will be testable with upcoming SZ surveys such as SPT-3G. While the stellar masses of FABLE BCGs are in reasonable agreement with observations, the total stellar mass in satellite galaxies is lower than observed and the total mass in ICL is somewhat higher. This may be caused by enhanced tidal stripping of satellite galaxies due to their large sizes. BCGs are characterised by moderate stellar mass growth at $z < 1$ coincident with a late-time development of the ICL. The level of BCG mass growth is in good agreement with recent observations, however, we caution that the inferred growth depends sensitively on the mass definition. We further show that in-situ star formation contributes more than half the mass of a BCG over its lifetime, the bulk of which is gained at $z > 1$ where star formation rates are highest. The stellar mass profiles of the BCG+ICL component are similar to observed profiles out to $\sim 100$ kpc at $z \approx 0$ and follow a close to power law shape out to several hundred kpc. We further demonstrate that the inferred size growth of BCGs can be severely biased by the choice of parametric model and the outer radius of the fit.
- [2] arXiv:1911.12369 [pdf, other]
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Title: A New Mask for An Old Suspect: Testing the Sensitivity of the Galactic Center Excess to the Point Source MaskComments: 9 pages, 8 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
The Fermi-LAT collaboration has recently released a new point source catalog, referred to as 4FGL. For the first time, we perform a template fit using information from this new catalog and find that the Galactic center excess is still present. On the other hand, we find that a wavelet-based search for point sources is highly sensitive to the use of the 4FGL catalog: no excess of bright regions on small angular scales is apparent when we mask out 4FGL point sources. We postulate that the 4FGL catalog contains the large majority of bright point sources that have previously been suggested to account for the excess in gamma rays detected at the Galactic center in Fermi-LAT data. Furthermore, after identifying which bright sources have no known counterpart, we place constraints on the luminosity function necessary for point sources to explain the smooth emission seen in the template fit.
- [3] arXiv:1911.12372 [pdf, ps, other]
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Title: Expanding the Y Dwarf Census with Spitzer Follow-up of the Coldest CatWISE Solar Neighborhood DiscoveriesAuthors: Aaron M. Meisner, Dan Caselden, J. Davy Kirkpatrick, Federico Marocco, Christopher R. Gelino, Michael C. Cushing, Peter R. M. Eisenhardt, Edward L. Wright, Jacqueline K. Faherty, Renata Koontz, Elijah J. Marchese, Mohammed Khalil, John W. Fowler, Edward F. SchlaflyComments: accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We present Spitzer 3.6$\mu$m and 4.5$\mu$m follow-up of 170 candidate extremely cool brown dwarfs newly discovered via the combination of WISE and NEOWISE imaging at 3$-$5$\mu$m. CatWISE, a joint analysis of archival WISE and NEOWISE data, has improved upon the motion measurements of AllWISE by leveraging a $>$10$\times$ time baseline enhancement, from 0.5 years (AllWISE) to 6.5 years (CatWISE). As a result, CatWISE motion selection has yielded a large sample of previously unrecognized brown dwarf candidates, many of which have archival detections exclusively in the WISE 4.6$\mu$m (W2) channel, suggesting that they could be both exceptionally cold and nearby. Where these objects go undetected in WISE W1 (3.4$\mu$m), Spitzer can provide critically informative detections at 3.6$\mu$m. Of our motion-confirmed discoveries, seventeen have a best-fit Spitzer [3.6]$-$[4.5] color most consistent with spectral type Y. CWISEP J144606.62$-$231717.8 ($\mu \approx 1.3''$/yr) is likely the reddest, and therefore potentially coldest, member of our sample with a very uncertain [3.6]$-$[4.5] color of 3.71 $\pm$ 0.44 magnitudes. We also highlight our highest proper motion discovery, WISEA J153429.75$-$104303.3, with $\mu \approx 2.7''$/yr. Given that the prior list of confirmed and presumed Y dwarfs consists of just 27 objects, the Spitzer follow-up presented in this work has substantially expanded the sample of identified Y dwarfs. Our new discoveries thus represent significant progress toward understanding the bottom of the substellar mass function, investigating the diversity of the Y dwarf population, and selecting optimal brown dwarf targets for JWST spectroscopy.
- [4] arXiv:1911.12375 [pdf, other]
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Title: From Peculiar Morphologies to Hubble-type Spirals: The relation between galaxy dynamics and morphology in star-forming galaxies at z~1.5Authors: S. Gillman (1), A. L. Tiley (1,2), A. M. Swinbank (1), C. M. Harrison (3), Ian Smail (1), U. Dudzevičiūtė (1), R. M. Sharples (1,4), L. Cortese (2,5), D. Obreschkow (2,6), R. G. Bower (1,7), T. Theuns (7), M. Cirasuolo (3), D. B. Fisher (8), K. Glazebrook (8), Edo Ibar (9), J. Trevor Mendel (10), Sarah M. Sweet (8,5) ((1) CEA, Durham, (2) ICRAR, Perth, (3) ESO, Münich, (4) CfAI, Durham, (5) ASTRO 3D, Australia, (6) CAASTRO, Sydney, (7) ICC, Durham, (8) CAS Swinburne, Australia, (9) Universidad de Valparaíso, Chile, (10) ANU, Canberra, Australia)Comments: Resubmitted to MNRAS following referees report. Comments welcome. 25 pages, 14 figures. The full pdf, which includes an additional 17 pages of supplementary figures is available on this $\rm \href{this http URL}{webpage}$Subjects: Astrophysics of Galaxies (astro-ph.GA)
We present an analysis of the gas dynamics of star-forming galaxies at z~1.5 using data from the KMOS Galaxy Evolution Survey (KGES). We quantify the morphology of the galaxies using $HST$ CANDELS imaging parametrically and non-parametrically. We combine the H$\alpha$ dynamics from KMOS with the high-resolution imaging to derive the relation between stellar mass (M$_{*}$) and stellar specific angular momentum (j$_{*}$). We show that high-redshift star-forming galaxies at z~1.5 follow a power-law trend in specific stellar angular momentum with stellar mass similar to that of local late-type galaxies of the form j$_*$$\propto$M$_*^{0.53 \pm 0.10}$. The highest specific angular momentum galaxies are mostly disc-like, although generally, both peculiar morphologies and disc-like systems are found across the sequence of specific angular momentum at a fixed stellar mass. We explore the scatter within the j$_{*}$-M$_{*}$ plane and its correlation with both the integrated dynamical properties of a galaxy (e.g. velocity dispersion, Toomre Q$_{\rm g}$, H$\alpha$ star formation rate surface density $\Sigma_{\rm SFR}$) and its parameterised rest-frame UV/optical morphology (e.g. S\'ersic index, bulge to total ratio, Clumpiness, Asymmetry and Concentration). We establish that the position in the j$_{*}$-M$_{*}$ plane is strongly correlated with the star-formation surface density and the Clumpiness of the stellar light distribution. Galaxies with peculiar rest-frame UV/optical morphologies have comparable specific angular momentum to disc-dominated galaxies of the same stellar mass, but are clumpier and have higher star-formation rate surface densities. We propose that the peculiar morphologies in high--redshift systems are driven by higher star formation rate surface densities and higher gas fractions leading to a more clumpy inter-stellar medium.
- [5] arXiv:1911.12378 [pdf, other]
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Title: Dynamical Masses of Young Stars II: Young Taurus Binaries Hubble~4, FF~Tau, and HP~Tau/G3Comments: 14 pages, 6 figures, 8 tables, accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
One of the most effective ways to test stellar evolutionary models is to measure dynamical masses for binary systems at a range of temperatures. In this paper, we present orbits of three young K+M binary systems in Taurus (Hubble~4, FF~Tau, and HP~Tau/G3) with VLBI parallaxes. We obtained precision astrometry with Keck-II/NIRC2, optical photometry with HST/WFC3, and low-resolution optical spectra with WIFeS on the ANU 2.3 m telescope. We fit orbital solutions and dynamical masses with uncertainties of 1-5% for the three binary systems. The spectrum, photometry, and mass for Hubble~4 are inconsistent with a binary system, suggesting that it may be a triple system where the primary component consists of two stars. For HP~Tau/G3 and FF~Tau, model masses derived from SED determined component temperatures and luminosities agree with the dynamical masses, with a small offset towards larger model masses. We find model ages for the primary components of these systems of $\sim$3 Myr, but find that the secondaries appear younger by a factor of two. These estimates also disagree with the age of the physically associated G-type star HP~Tau/G2, which is older ($\sim$5 Myr) according to the same models. This discrepancy is equivalent to a luminosity under-prediction of 0.1-0.2 dex, or a temperature over-prediction of 100-300 K, for K/M-type stars at a given model age. We interpret this as further evidence for a systematic error in pre-main sequence evolutionary tracks for convective stars. Our results reinforce that the ages of young populations determined from the locus of M-type members on the HR-diagram may require upward revision.
- [6] arXiv:1911.12395 [pdf, other]
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Title: BAT AGN Spectroscopic Survey -- XIX: Type 1 versus Type 2 AGN dichotomy from the point of view of ionized outflowsAuthors: A.F. Rojas, E. Sani, I. Gavignaud, C.Ricci, I. Lamperti, M. Koss, B. Trakhtenbrot, K. Schawinski, K. Oh, F.E.Bauer, M. Bischetti, R. Boissay-Malaquin, A. Bongiorno, F. Harrison, D. Kakkad, N. Masetti, F. Ricci, T. Shimizu, M. Stalevski, D. Stern, G. VietriComments: Accepted for publication in MNRAS, 15 pages, 19 figures, 1 tableSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present a detailed study of ionized outflows in a large sample of ~650 hard X-ray detected AGN. Using optical spectroscopy from the BAT AGN Spectroscopic Survey (BASS) we are able to reveal the faint wings of the [OIII] emission lines associated with outflows covering, for the first time, an unexplored range of low AGN bolometric luminosity at low redshift (z~0.05). We test if and how the incidence and velocity of ionized outflow is related to AGN physical parameters: black hole mass, gas column density, Eddington Ratio, [OIII], X-ray, and bolometric luminosities. We find a higher occurrence of ionized outflows in type 1.9 (55%) and type 1 AGN (46%) with respect to type 2 AGN (24%). While outflows in type 2 AGN are evenly balanced between blue and red velocity offsets with respect to the [OIII] narrow component, they are almost exclusively blueshifted in type 1 and type 1.9 AGN. We observe a significant dependence between the outflow occurrence and accretion rate, which becomes relevant at high Eddington ratios (> -1.7). We interpret such behaviour in the framework of covering factor-Eddington ratio dependence. We don't find strong trends of the outflow maximum velocity with AGN physical parameters, as an increase with bolometric luminosity can be only identified when including samples of AGN at high luminosity and high redshift taken from literature.
- [7] arXiv:1911.12398 [pdf, other]
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Title: Modeling the accretion disk around the high-mass protostar GGD 27-MM1Authors: N. Añez-Lopez, M. Osorio, G. Busquet, J. M. Girart, E. Macıas, C. Carrasco-Gonzalez, S. Curiel, R. Estalella, M. Fernandez-Lopez, R. Galvan-Madrid, J. Kwon, J.M. TorrellesComments: 20 pages, 15 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Recent high-angular resolution (40 mas) ALMA observations at 1.14 mm resolve a compact (R~200 au) flattened dust structure perpendicular to the HH 80-81 jet emanating from the GGD 27-MM1 high-mass protostar, making it a robust candidate for a true accretion disk. The jet/disk system (HH 80-81 / GGD 27-MM1) resemble those found in association with low- and intermediate-mass protostars. We present radiative transfer models that fit the 1.14 mm ALMA dust image of this disk which allow us to obtain its physical parameters and predict its density and temperature structure. Our results indicate that this accretion disk is compact (Rdisk~170 au) and massive (5Msun), about 20% of the stellar mass of 20 Msun. We estimate the total dynamical mass of the star-disk system from the molecular line emission finding a range between 21 and 30 Msun, which is consistent with our model. We fit the density and temperature structures found by our model with power law functions. These results suggest that accretion disks around massive stars are more massive and hotter than their low-mass siblings, but they still are quite stable. We also compare the temperature distribution in the GGD 27-MM1 disk with that found in low- and intermediate-mass stars and discuss possible implications on the water snow line. We have also carried about a study of the distance based on Gaia DR2 data and the population of young stellar objects (YSOs) in this region, and from the extinction maps. We conclude that the source distance is in within 1.2 and 1.4 kpc, closer than what was derived in previous studies (1.7 kpc).
- [8] arXiv:1911.12415 [pdf, other]
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Title: Third components with elliptical orbits in the eclipsing binaries: AB Cas, AF Gem, AR Boo, BF Vir and CL AurAuthors: Dmytro TvardovskyiComments: 5 pages, 6 figures, part of the series of articles "Third components with elliptical orbits in the eclipsing binaries"Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
In this research, five eclipsing binary stars were studied: AB Cas, AF Gem, AR Boo, BF Vir and CL Aur. The large sets of moments of minima were used: from the international BRNO database and amateur observations from the database AAVSO. Firstly, moments of minima for AAVSO observations were obtained (totally - 222 minima). The software MAVKA was used. It was kindly provided by Kateryna D. Andrych and Ivan L. Andronov (2019OEJV..197...65A) and approximation with various methods in order to find the best fit. Then all obtained moments of minima were combined and O-C diagrams were plotted. For all stars these diagrams represented sinusoidal-like oscillations with superposition of parabolic trend. One of the possible reasons for such oscillations could be presence of well-known light-time effect (LTE) caused by third component with elliptical orbit. Parabolic trend was explained as mass transfer between components of binary system. For all these stars we computed possible mass of the third component, orbital elements, mass transfer rate and errors for all computed values.
- [9] arXiv:1911.12418 [pdf, other]
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Title: QUBIC: using NbSi TESs with a bolometric interferometer to characterize the polarisation of the CMBAuthors: M. Piat, B. Bélier, L. Bergé, N. Bleurvacq, C. Chapron, S. Dheilly, L. Dumoulin, M. González, L. Grandsire, J.-Ch. Hamilton, S. Henrot-Versillé, D.T. Hoang, S. Marnieros, W. Marty, L. Montier, E. Olivieri, C. Oriol, C. Perbost, D. Prêle, D. Rambaud, M. Salatino, G. Stankowiak, J.-P. Thermeau, S. Torchinsky, F. Voisin, P. Ade, J.G. Alberro, A. Almela, G. Amico, L. H. Arnaldi, D. Auguste, J. Aumont, S. Azzoni, S. Banfi, P. Battaglia, E.S. Battistelli, A. Baù, D. Bennett, J.-Ph. Bernard, M. Bersanelli, M.-A. Bigot-Sazy, J. Bonaparte, J. Bonis, A. Bottani, E. Bunn, D. Burke, D. Buzi, A. Buzzelli, F. Cavaliere, P. Chanial, R. Charlassier, F. Columbro, G. Coppi, A. Coppolecchia, G. D'Alessandro, P. de Bernardis, G. De Gasperis, M. De Leo, M. De Petris, A. Di Donato, et al. (78 additional authors not shown)Comments: Conference proceedings submitted to the Journal of Low Temperature Physics for LTD18Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
QUBIC (Q \& U Bolometric Interferometer for Cosmology) is an international ground-based experiment dedicated in the measurement of the polarized fluctuations of the Cosmic Microwave Background (CMB). It is based on bolometric interferometry, an original detection technique which combine the immunity to systematic effects of an interferometer with the sensitivity of low temperature incoherent detectors. QUBIC will be deployed in Argentina, at the Alto Chorrillos mountain site near San Antonio de los Cobres, in the Salta province.
The QUBIC detection chain consists in 2048 NbSi Transition Edge Sensors (TESs) cooled to 350mK.The voltage-biased TESs are read out with Time Domain Multiplexing based on Superconducting QUantum Interference Devices (SQUIDs) at 1 K and a novel SiGe Application-Specific Integrated Circuit (ASIC) at 60 K allowing to reach an unprecedented multiplexing (MUX) factor equal to 128.
The QUBIC experiment is currently being characterized in the lab with a reduced number of detectors before upgrading to the full instrument. I will present the last results of this characterization phase with a focus on the detectors and readout system. - [10] arXiv:1911.12424 [pdf, other]
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Title: Escapees from the bar resonances. On the presence of low-eccentricity, metal-rich stars at the Solar vicinityComments: 9 pages, 8 figures, submitted to A&ASubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Understanding radial migration is a crucial point to build relevant chemical and dynamical evolution models of the Milky Way disk. In this paper, we analyze a high-resolution N-body simulation of a Milky Way-type galaxy to study the role that the slowing down of a stellar bar has is generating migration from the inner to the outer disk. Stellar particles are trapped by the main resonances (corotation and Outer Lindblad resonance) which then propagate outwards across the disk due to the bar slowing down. Once the bar strength reaches its maximal amplitude, some of the stars, delivered to the outer disk, escape the resonances and some of them settle on nearly circular orbits. The number of the escaped stars gradually increases also due to the decrease of the bar strength when the boxy/peanut bulge forms. We show that this mechanism is not limited only to stars on nearly circular orbits: also stars initially on more eccentric orbits can be transferred outwards (out to the OLR location) and can end up on nearly circular orbits. Therefore, the propagation of the bar resonances outwards can induce the circularization of the orbits of some of the migrating stars. The mechanism investigated in this paper can explain the presence of metal-rich stars at the solar vicinity and more generally in the outer galactic disk. Our dynamical model predicts that up to 3% of stars in between of corotation and the OLR can be formed in the innermost region of the Milky Way. The epoch of the Milky Way bar formation can be potentially constrained by analyzing the age distribution of the most metal-rich stars at the solar vicinity.
- [11] arXiv:1911.12434 [pdf, other]
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Title: Midplane temperature and outer edge of the protoplanetary disk around HD 163296Comments: Accepted for publication in Astronomy and AstrophysicsSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Knowledge of the midplane temperature of protoplanetary disks is one of the key ingredients in theories of dust growth and planet formation. However, direct measurement of this quantity is complicated, and often depends on the fitting of complex models to the data. In this paper we demonstrate a method to directly measure the midplane gas temperature from an optically thick molecular line, if the disk is moderately inclined. The only model assumption that enters is that the line is very optically thick, also in the midplane region where we wish to measure the temperature. Freeze-out of the molecule onto dust grains could thwart this. However, in regions that are expected to be warm enough to avoid freeze-out, this method should work. We apply the method to the CO 2-1 line channel maps of the disk around HD 163296. We find that the midplane temperature between 100 and 400 au drops only mildly from 25 K down to 18 K. While we see no direct evidence of the midplane being optically thin due to strong CO depletion by freeze-out, we cannot rule it out either. The fact that the inferred temperatures are close to the expected CO freeze-out temperature could be an indication of this. Incidently, for the disk around HD 163296 we also find dynamic evidence for a rather abrupt outer edge of the disk, suggestive of outside-in photoevaporation or truncation by an unseen companion.
- [12] arXiv:1911.12455 [pdf, other]
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Title: Structural analysis of massive galaxies using HST deep imaging at z < 0.5Authors: Sandra N. dos Reis, Fernando Buitrago, Polychronis Papaderos, Israel Matute, José Afonso, Stergios Amarantidis, Iris Breda, Jean M. Gomes, Andrew Humphrey, Catarina Lobo, Silvio Lorenzoni, Cirino Pappalardo, Ana Paulino-Afonso, Tom ScottSubjects: Astrophysics of Galaxies (astro-ph.GA)
Taking advantage of HST CANDELS data, we analyze the lowest redshift (z<0.5) massive galaxies in order to disentangle their structural constituents and study possible faint non-axis-symmetric features. Due to the excellent HST spatial resolution for intermediate-z objects, they are hard to model by purely automatic parametric fitting algorithms. We performed careful single and double S\'ersic fits to their galaxy surface brightness profiles. We also compare the model color profiles with the observed ones and also derive multi-component global effective radii attempting to obtain a better interpretation of the mass-size relation. Additionally, we test the robustness of our measured structural parameters via simulations. We find that the S\'ersic index does not offer a good proxy for the visual morphological type for our sample of massive galaxies. Our derived multi-component effective radii give a better description of the size of our sample galaxies than those inferred from single S\'ersic models with GALFIT. Our galaxy population lays on the scatter of the local mass-size relation, indicating that these massive galaxies do not experience a significant growth in size since z~0.5. Interestingly the few outliers are late-type galaxies, indicating that spheroids must reach the local mass-size relation earlier. For most of our sample galaxies, both single and multi-component S\'ersic models with GALFIT show substantial systematic deviations from the observed SBPs in the outskirts. These residuals may be partly due to several factors, namely a non-optimal data reduction for low surface brightness features, the existence of prominent stellar haloes for massive galaxies and could also arise from conceptual shortcomings of parametric 2D image decomposition tools. They consequently propagate into galaxy color profiles.
- [13] arXiv:1911.12496 [pdf, other]
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Title: Thanks for the memory: measuring gravitational-wave memory in the first LIGO/Virgo gravitational-wave transient catalogComments: 6 pages, 3 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
Gravitational-wave memory, a strong-field effect of general relativity, manifests itself as a permanent displacement in spacetime. We develop a Bayesian framework to detect gravitational-wave memory with the Advanced LIGO/Virgo detector network. We apply this algorithm on the ten binary black hole mergers in LIGO/Virgo's first transient gravitational-wave catalog. We find no evidence of memory, which is consistent with expectations. In order to estimate when memory will be detected, we use the best current population estimates to construct a realistic sample of binary black hole observations for LIGO/Virgo at design sensitivity. We show that an ensemble of $\mathcal{O}(2000)$ binary black hole observations can be used to find definitive evidence for gravitational-wave memory. We conclude that memory is likely to be detected in the early A+/Virgo+ era.
- [14] arXiv:1911.12499 [pdf, other]
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Title: Ultrasensitive optomechanical detection of an axion-mediated force based on a sharp peak emerging in probe absorption spectrumComments: arXiv admin note: text overlap with arXiv:1910.11338Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
Axion remains the most convincing solution to the strong-CP problem and a well-motivated dark matter candidate, causing the search for axions and axion-like particles(ALPs) to attract attention continually. The exchange of such particles may cause anomalous spin-dependent forces, inspiring many laboratory ALP searching experiments based on the detection of macroscopic monopole-dipole interactions between polarized electrons/nucleons and unpolarized nucleons. Since there is no exact proof of the existence of these interactions, to detect them is still of great significance. In the present paper, we study the electron-neucleon monopole-dipole interaction with a new method, in which a hybrid spin-nanocantilever optomechanical system consisting of a nitrogen-vacancy(NV) center and a nanocantilever resonator is used. With a static magnetic field and a pump microwave beam and a probe microwave beam applied, a probe absorption spectrum could be obtained. Through specific peaks appearing in the spectrum, we can identify this monopole-dipole interaction. And we also provide a prospective constraint to constrain the interaction. Furthermore, because our method can also be applied to the detection of some other spin-dependent interactions, this work provides new ideas for the experimental searches of the anomalous spin-dependent interactions.
- [15] arXiv:1911.12532 [pdf, other]
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Title: The Intergalactic medium transmission towards z>4 galaxies with VANDELS and the impact of dust attenuationAuthors: R. Thomas, L. Pentericci, O. Le Fèvre, G. Zamorani, D. Schaerer, R. Amorin, M. Castellano, A. C. Carnall, S. Cristiani, F. Cullen, S. L. Finkelstein, F. Fontanot, L. Guaita, P. Hibon, N. Hathi, J. P. U. Fynbo, Y. Khusanova, A. M. Koekemoer, D. McLeod, R. J. McLure, F. Marchi, L. Pozzetti, A. Saxena, M. Talia, M. BolzonellaComments: Accepted for publication in A&ASubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
Aims. Our aim is to estimate the intergalactic medium transmission towards UV-selected star-forming galaxies at redshift 4 and above and study the effect of the dust attenuation on these measurements.
Methods. The ultra-violet spectrum of high redshift galaxies is a combination of their intrinsic emission and the effect of the Inter-Galactic medium (IGM) absorption along their line of sight. Using data coming from the unprecedented deep spectroscopy from the VANDELS ESO public survey carried out with the VIMOS instrument we compute both the dust extinction and the mean transmission of the IGM as well as its scatter from a set of 281 galaxies at z>3.87. Because of a degeneracy between the dust content of the galaxy and the IGM, we first estimate the stellar dust extinction parameter E(B-V) and study the result as a function of the dust prescription. Using these measurements as constraint for the spectral fit we estimate the IGM transmission Tr(Lyalpha). Both photometric and spectroscopic SED fitting are done using the SPectroscopy And photometRy fiTting tool for Astronomical aNalysis (SPARTAN) that is able to fit the spectral continuum of the galaxies as well as photometric data.
Results. Using the classical Calzetti's attenuation law we find that E(B-V) goes from 0.11 at z=3.99 to 0.08 at z=5.15. These results are in very good agreement with previous measurements from the literature. We estimate the IGM transmission and find that the transmission is decreasing with increasing redshift from Tr(Lyalpha)=0.53 at z=3.99 to 0.28 at z=5.15. We also find a large standard deviation around the average transmission that is more than 0.1 at every redshift. Our results are in very good agreement with both previous measurements from AGN studies and with theoretical models. - [16] arXiv:1911.12577 [pdf, other]
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Title: Hunting ghosts: the iconic stellar stream(s) around NG5907 under scrutinyComments: accepted for publication in A&A Letters, 5 pages, 3 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Stellar streams are regarded as crucial objects to test galaxy formation models, with their morphology tracing the underlying potentials and their occurrence tracking the assembly history of the galaxies. The existence of one of the most iconic stellar streams, the double loop around NGC5907, has recently been questioned by new observations with the Dragonfly telescope. This new work only finds parts of the stream, even though they reach a 1 sigma surface brightness limit of 30.3 mag per sq. arcsec in the g-band. Using 7.2 hours of Luminance L-band imaging with the Milankovi\'c 1.4 meter telescope, we have re-observed the putative double loop part to confirm or reject this assessment. We do not find signs of the double loop, but see only a single, knee-shaped stellar stream. Comparing our to the data by the Dragonfly team, we find the same features. Our observations reach a 1 sigma surface brightness limit of 29.7 mag per sq. arcsec in the g-band. These findings emphasize the need for independent confirmation of detections of very low-surface brightness features.
- [17] arXiv:1911.12581 [pdf, ps, other]
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Title: Constraints on the binary black hole hypothesis for system LB-1Authors: R.-F. Shen (1), C. D. Matzner (2), A. W. Howard (3), W. Zhang (4) ((1) SYSU, (2) U of Toronto, (3) Caltech, (4) NAOC)Comments: 5 pages, submitted to ApJLSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
At about 70 solar masses, the recently-discovered dark object orbited by a B-type star in the system LB-1 is difficult to understand as the end point of standard stellar evolution, except as a binary black hole (BBH). LB-1 shows a strong, broad H-alpha emission line that is best attributed to a gaseous disk surrounding the dark mass. We use the observed H-alpha line shape, particularly its wing extension, to constrain the inner radius of the disk and thereby the separation of a putative BBH. The hypothesis of a current BBH is effectively ruled out on the grounds that its merger time must be a small fraction of the current age of the B star. The hypothesis of a previous BBH that merged to create the current dark mass is also effectively ruled out by the low orbital eccentricity, due to the combination of mass loss and kick resulted from gravitational wave emission in any past merger. We conclude that the current dark mass is a single black hole produced by the highly mass-conserving, monolithic collapse of a massive star.
- [18] arXiv:1911.12621 [pdf, other]
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Title: Real-time flare prediction based on distinctions between flaring and non-flaring active region spectraSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
With machine learning entering into the awareness of the heliophysics community, solar flare prediction has become a topic of increased interest. Although machine learning models have advanced with each successive publication, the input data has remained largely fixed on magnetic features. Despite this increased model complexity, results seem to indicate that photospheric magnetic field data alone may not be a wholly sufficient source of data for flare prediction. For the first time we have extended the study of flare prediction to spectral data. In this work, we use Deep Neural Networks to monitor the changes of several features derived from the strong resonant Mg II h&k lines observed by IRIS. The features in descending order of predictive capability are: The triplet emission at 2798.77 {\AA}, line core intensity, total continuum emission between the h&k line cores, the k/h ratio, line-width, followed by several other line features such as asymmetry and line center. Regions that are about to flare generate spectra which are distinguishable from non-flaring active region spectra. Our algorithm can correctly identify pre-flare spectra approximately 35 minutes before the start of the flare, with an 80% accuracy, precision and recall. This accuracy monotonically increases to 90% as we move closer in time to the start of the flare. Our study indicates that spectral data alone can lead to good predictive models and should be considered as an additional source of information alongside photospheric magnetograms.
- [19] arXiv:1911.12628 [pdf, other]
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Title: Detection of Na, K and H$_2$O in the hazy atmosphere of WASP-6bAuthors: Aarynn L. Carter, Nikolay Nikolov, David K. Sing, Munazza K. Alam, Jayesh M. Goyal, Thomas Mikal-Evans, Hannah R. Wakeford, Gregory W. Henry, Sam Morrell, Mercedes López-Morales, Barry Smalley, Panayotis Lavvas, Joanna K. Barstow, Antonio García Muñoz, Paul A. Wilson, Neale P. GibsonComments: Submitted to MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We present new observations of the transmission spectrum of the hot Jupiter WASP-6b both from the ground with the Very Large Telescope (VLT) FOcal Reducer and Spectrograph (FORS2) from 0.45-0.83 $\mu$m, and space with the Transiting Exoplanet Survey Satellite (TESS) from 0.6-1.0 $\mu$m and the Hubble Space Telescope (HST) Wide Field Camera 3 from 1.12-1.65 $\mu$m. Archival data from the HST Space Telescope Imaging Spectrograph (STIS) and Spitzer is also reanalysed on a common Gaussian process framework, of which the STIS data show a good overall agreement with the overlapping FORS2 data. We also explore the effects of stellar heterogeneity on our observations and its resulting implications towards determining the atmospheric characteristics of WASP-6b. Independent of our assumptions for the level of stellar heterogeneity we detect Na I, K I and H$_2$O absorption features and constrain the elemental oxygen abundance to a value of [O/H] $\simeq -0.9\pm0.3$ relative to solar. In contrast, we find that the stellar heterogeneity correction can have significant effects on the retrieved distributions of the [Na/H] and [K/H] abundances, primarily through its degeneracy with the sloping optical opacity of scattering haze species within the atmosphere. Our results also show that despite this presence of haze, WASP-6b remains a favourable object for future atmospheric characterisation with upcoming missions such as the James Webb Space Telescope.
- [20] arXiv:1911.12634 [pdf, other]
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Title: VLBI observations of the G25.65+1.05 water maser superburstAuthors: R. A. Burns, G. Orosz, O. Bayandina, G. Surcis, M. Olech, G. MacLeod, A. Volvach, G. Rudnitskii, T. Hirota, K. Immer, J. Blanchard, B. Marcote, H. J. van Langevelde, J. O. Chibueze, K. Sugiyama, Kee-Tae Kim, I. Val`tts, N. Shakhvorostova, B. Kramer, W. A. Baan, C. Brogan, T. Hunter, S. Kurtz, A. M. Sobolev, J. Brand, L. VolvachSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
This paper reports observations of a 22 GHz water maser `superburst' in the G25.65+1.05 massive star forming region, conducted in response to an alert from the Maser Monitoring Organisation (M2O). Very long baseline interferometry (VLBI) observations using the European VLBI Network (EVN) recorded a maser flux density of $1.2 \times 10^{4}$ Jy. The superburst was investigated in the spectral, structural and temporal domains and its cause was determined to be an increase in maser path length generated by the superposition of multiple maser emitting regions aligning in the line of sight to the observer. This conclusion was based on the location of the bursting maser in the context of the star forming region, its complex structure, and its rapid onset and decay.
- [21] arXiv:1911.12636 [pdf, ps, other]
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Title: High-resolution spectroscopy of the high velocity hot post-AGB star IRAS 18379-1707 (LS 5112)Comments: Accepted by MNRAS, 18 pages, 13 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The high-resolution ($R\sim48\,000$) optical spectrum of the B-type supergiant LS 5112, identified as the optical counterpart of the post-AGB candidate IRAS 18379-1707, is analysed. We report the detailed identifications of the observed absorption and emission features in the wavelength range 3700-9200 A for the first time. The absorption line spectrum has been analysed using non-LTE model atmosphere techniques to determine stellar atmospheric parameters and chemical composition. We estimate $T_\text{eff}=18~000\pm1000$ K, $\log g=2.25\pm0.08$, $\xi_{\rm t}=10\pm4$ km/s and $v \sin i=37\pm6$ km/s, and the derived abundances indicate a metal-deficient ([M/H]$\approx-0.6)$ post-AGB star. Chemical abundances of eight different elements were obtained. The estimates of the CNO abundances in IRAS 18379-1707 indicate that these elements are overabundant with [(C+N+O)/S]=+0.5$\pm$0.2 suggesting that the products of helium burning have been brought to the surface as a result of third dredge-up on the AGB. From the absorption lines, we derived heliocentric radial velocity of $V_\text{r}=-124.0\pm0.4$ km/s. We have identified permitted emission lines of O I, N I, Na I, S II, Si II, C II, Mg II and Fe III. The nebula forbidden lines of [N I], [O I], [Fe II], [N II], [S II], [Ni II] and [Cr II] have also been identified. The Balmer lines H$\alpha$, H$\beta$ and H$\gamma$ show P-Cygni behaviour clearly indicating post-AGB mass-loss process in the object with the wind velocity up to 170 km/s.
- [22] arXiv:1911.12658 [pdf, ps, other]
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Title: Constraints on the cosmic string loop collapse fraction from Primordial Black HolesComments: 5 pagesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
A small fraction, $f$, of cosmic string loops can collapse to form Primordial Black Holes (PBHs). Constraints on the abundance of PBHs can therefore be used to constrain $f$. We update these calculations, taking into account the PBH extended mass function, and find $f < 10^{-32} (G \mu/ c^2)^{-3/2}$. This is roughly two orders of magnitude tighter than previous constraints. The improvement from the tighter constraints on the abundance of PBHs is partly off-set by refinements to the theoretical calculation of the cosmic string loop formation rate.
- [23] arXiv:1911.12666 [pdf, ps, other]
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Title: Spectropolarimetric Insight into Plasma-Sheet Dynamics of a Solar FlareComments: 9 pages, 4 figures; accepted for publication to ApJ LettersSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph); Space Physics (physics.space-ph)
We examine spectropolarimetric data from the CoMP instrument, acquired during the evolution of the September 10th 2017 X8.2 solar flare on the western solar limb. CoMP captured linearly polarized light from two emission lines of Fe XIII at 1074.7 and 1079.8 nm, from 1.03 to 1.5 solar radii. We focus here on the hot plasma-sheet lying above the bright flare loops and beneath the ejected CME. The polarization has a striking and coherent spatial structure, with unexpectedly small polarization aligned with the plasma-sheet. By elimination, we find that small-scale magnetic field structure is needed to cause such significant depolarization, and suggest that plasmoid formation during reconnection (associated with the tearing mode instability) creates magnetic structure on scales below instrument resolution of 6 Mm. We conclude that polarization measurements with new coronagraphs, such as the upcoming DKIST, will further enhance our understanding of magnetic reconnection and development of turbulence in the solar corona.
- [24] arXiv:1911.12685 [pdf, other]
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Title: Primordial black hole merger rates: distributions for multiple LIGO observablesComments: 23 pages + appendices, 17 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
We have calculated the detectable merger rate of primordial black holes, as a function of the redshift, as well as the binary's mass ratio, total mass and chirp mass (observables that have not previously been explored in great detail for PBHs). We consider both the current and design sensitivity of LIGO and five different primordial black hole mass functions, as well as showing a comparison to a predicted astrophysical black hole merger rate. We show that the empirical preference for nearly equal-mass binaries in current LIGO/Virgo data can be consistent with a PBH hypothesis once observational selection effects are taken into account. However, current data do exclude some PBH mass distributions, and future data may be able to rule out the possibility that all observed BH mergers had a primordial origin.
- [25] arXiv:1911.12687 [pdf, ps, other]
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Title: Modeling the Thermal Bulge of A Hot Jupiter with the Two-Stream ApproximationComments: Accepted for the publication in ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We revisit the problem of thermal bulge of asynchronous hot Jupiters, using HD 209458 b as a fiducial study. We improve upon previous works by using a double-gray atmosphere model and interior structure from MESA as the background state, and then solve for the thermal bulge in response to the semidiurnal component of stellar insolation. The atmosphere model is based on the radiative transfer with Eddington's two-stream approximation. Two opacity cases are considered: the first introduces a greenhouse effect and the second exhibits a strong temperature inversion. We find that for the predominant thermal bulges excited by g-modes of lower orders, our results are qualitatively similar to the adiabatic results from Arras and Socrates (2010). It arises because the perturbed heating due to self-absorption of thermal emissions can be significant (i.e., greenhouse effect) against Newtonian damping, thereby leading to almost undamped thermal bulges. We also find that the contribution to the thermal bulge from the evanescent waves in the convective zone is not negligible, implying that the thermal bulge is not merely confined in the atmosphere and radiative envelope. Assuming the torque balance between the thermal and gravitational bulges, we estimate the tidal quality factor of the planet for gravitational tides to match the observed radius. The limitations of our model are also briefly discussed.
- [26] arXiv:1911.12702 [pdf]
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Title: Sunspot Observations by Hisako Koyama: 1945-1996Authors: Hisashi Hayakawa, Frédéric Clette, Toshihiro Horaguchi, Tomoya Iju, Delores J. Knipp, Huixin Liu, Takashi NakajimaComments: Main text 31 pages, references 6 pages, 13 figures, 3 tabes, accepted for publication in Monthly Notices of the Royal Astronomical Society, 2020Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
The sunspot record is the only observational tracer of solar activity that provides a fundamental, multi-century reference. Its homogeneity has been largely maintained with a succession of long-duration visual observers. In this paper, we examine observations of one of the primary reference sunspot observers, Hisako Koyama. By consulting original archives of the National Museum of Nature and Science of Japan (hereafter, NMNS), we retrace the main steps of her solar-observing career, from 1945 to 1996. We also present the reconstruction of a full digital database of her sunspot observations at the NMNS, with her original drawings and logbooks. Here, we extend the availability of her observational data from 1947-1984 to 1945-1996. Comparisons with the international sunspot number (version 2) and with the group sunspot number series show a good global stability of Koyama's observations, with only temporary fluctuations over the main interval 1947-1982. Identifying drawings made by alternate observers throughout the series, we find that a single downward baseline shift in the record coincides with the partial contribution of replacement observers mostly after 1983. We determine the correction factor to bring the second part (1983-1996) to the same scale with Koyama's main interval (1947-1982). We find a downward jump by 9% after 1983, which then remains stable until 1996. Overall, the high quality of Koyama's observations with her life-long dedication leaves a lasting legacy of this exceptional personal achievement. With this comprehensive recovery, we now make the totality of this legacy directly accessible and exploitable for future research.
- [27] arXiv:1911.12713 [pdf, other]
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Title: Sengi: a small, fast, interactive viewer for spectral outputs from stellar population synthesis modelsAuthors: Christopher C. LovellComments: 7 pages, 6 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)
We present Sengi ( christopherlovell.github.io/sengi, https://christopherlovell.github.io/sengi ), an online tool for viewing the spectral outputs of stellar population synthesis (SPS) codes. Typical SPS codes require significant disk space or computing resources to produce spectra for simple stellar populations with arbitrary parameters. This makes it difficult to present their results in an interactive, web-friendly format. Sengi uses Non-negative Matrix Factorisation (NMF) and bilinear interpolation to estimate output spectra for arbitrary values of stellar age and metallicity. The reduced disk requirements and computational expense allows the result to be served as a client-based Javascript application. In this paper we present the method for generating grids of spectra, fitting those grids with NMF, bilinear interpolation across the fitted coefficients, and finally provide estimates of the prediction and interpolation errors.
- [28] arXiv:1911.12734 [pdf, other]
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Title: Magnetic Rayleigh-Taylor Instability at a Contact Discontinuity With Oblique Magnetic FieldComments: 9 pages, 13 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Aims: In the present work we investigate the nature of the magnetic Rayleigh-Taylor instability at a density interface permeated by an oblique, homogeneous magnetic field in an incompressible limit. Methods: Using the system of linearised ideal incompressible magnetohydrodynamics (MHD) equations we derive the dispersion relation for perturbations of the contact discontinuity by imposing the necessary continuity conditions at the interface. The imaginary part of the frequency describes the growth rate of waves due to instability. The growth rate of waves is studied by solving numerically the dispersion relation. Results: The critical wavenumber at which waves become unstable, present for a parallel magnetic field, disappears, due to the inclination of the magnetic field and instead waves are shown to be unstable for all wavenumbers. Theoretical results are applied to diagnose the structure of the magnetic field in prominence threads. When applying our theoretical results to observed waves in prominence plumes, we obtain a wide range of field inclination angle; from 0.5 degrees up to 30 degrees. These results highlight the diagnostic possibility of our study.
- [29] arXiv:1911.12745 [pdf, other]
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Title: Machine learning inference of the interior structure of low-mass exoplanetsAuthors: Philipp Baumeister, Sebastiano Padovan, Nicola Tosi, Grégoire Montavon, Nadine Nettelmann, Jasmine MacKenzie, Mareike GodoltComments: 14 pages, 7 figures, accepted for publication in ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We explore the application of machine learning based on mixture density neural networks (MDNs) to the interior characterization of low-mass exoplanets up to 25 Earth masses constrained by mass, radius, and fluid Love number $k_2$. We create a dataset of 900$\:$000 synthetic planets, consisting of an iron-rich core, a silicate mantle, a high-pressure ice shell, and a gaseous H/He envelope, to train a MDN using planetary mass and radius as inputs to the network. For this layered structure, we show that the MDN is able to infer the distribution of possible thicknesses of each planetary layer from mass and radius of the planet. This approach obviates the time-consuming task of calculating such distributions with a dedicated set of forward models for each individual planet. While gas-rich planets may be characterized by compositional gradients rather than distinct layers, the method presented here can be easily extended to any interior structure model. The fluid Love number $k_2$ bears constraints on the mass distribution in the planets' interior and will be measured for an increasing number of exoplanets in the future. Adding $k_2$as an input to the MDN significantly decreases the degeneracy of the possible interior structures.
- [30] arXiv:1911.12751 [pdf, ps, other]
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Title: Galactic dust evolution with rapid dust formation in the interstellar medium due to hypersonic turbulenceAuthors: Lars MattssonComments: 11 pages, 5 figures. Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
Turbulence can significantly accelerate the growth of dust grains by accretion of molecules. For dust dynamically coupled to the gas, the growth rate scales with the square of the Mach number, which means that the growth timescale can easily be reduced by more than an order of magnitude. The limiting timescale is therefore rather the rate of molecular cloud formation, which means that dust production in the ISM can rapidly reach the levels needed to explain the dust masses observed at high redshifts. Thus, turbulence may be the solution to the replenishment problem in models of dust evolution in high-redshift galaxies and explain the dust masses seen at $z = 7 - 8$. A simple analytic galactic dust-evolution model is presented, where grain growth nicely compensates for the expected higher rate of dust destruction by supernova shocks. This model is simpler, relies on fewer assumptions and seems to yields a better fit to data derived from observations, compared to previous models of the same type.
- [31] arXiv:1911.12759 [pdf, other]
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Title: RefPlanets: Search for reflected light from extra-solar planets with SPHERE/ZIMPOLAuthors: S. Hunziker, H. M. Schmid, D. Mouillet, J. Milli, A. Zurlo, P. Delorme, L. Abe, H. Avenhaus, A. Baruffolo, A. Bazzon, A. Boccaletti, P. Baudoz, J. L. Beuzit, M. Carbillet, G. Chauvin, R. Claudi, A. Costille, J. B. Daban, S. Desidera, K. Dohlen, C. Dominik, M. Downing, N. Engler, M. Feldt, T. Fusco, C. Ginski, D. Gisler, J. H. Girard, R. Gratton, Th. Henning, N. Hubin, M. Kasper, C. U. Keller, M. Langlois, E. Lagadec, P. Martinez, A. L. Maire, F. Menard, M. R. Meyer, A. Pavlov, J. Pragt, P. Puget, S. P. Quanz, E. Rickman, R. Roelfsema, B. Salasnich, J. F. Sauvage, R. Siebenmorgen, E. Sissa, F. Snik, M. Suarez, J. Szulagyi, Ch. Thalmann, M. Turatto, S. Udry, R. G. van Holstein, A. Vigan, F. WildiComments: 23 pages, 17 figures, 2 table, Accepted for publication in A&ASubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
RefPlanets is a guaranteed time observation (GTO) programme that uses the Zurich IMaging POLarimeter (ZIMPOL) of SPHERE/VLT for a blind search for exoplanets in wavelengths from 600-900 nm. The goals of this study are the characterization of the unprecedented high polarimetic contrast and polarimetric precision capabilities of ZIMPOL for bright targets, the search for polarized reflected light around some of the closest bright stars to the Sun and potentially the direct detection of an evolved cold exoplanet for the first time. For our observations of Alpha Cen A and B, Sirius A, Altair, Eps Eri and Tau Ceti we used the polarimetric differential imaging (PDI) mode of ZIMPOL which removes the speckle noise down to the photon noise limit for angular separations >0.6". We describe some of the instrumental effects that dominate the noise for smaller separations and explain how to remove these additional noise effects in post-processing. We then combine PDI with angular differential imaging (ADI) as a final layer of post-processing to further improve the contrast limits of our data at these separations. For good observing conditions we achieve polarimetric contrast limits of 15.0-16.3 mag at the effective inner working angle of about 0.13", 16.3-18.3 mag at 0.5" and 18.8-20.4 mag at 1.5". The contrast limits closer in (<0.6") depend significantly on the observing conditions, while in the photon noise dominated regime (>0.6"), the limits mainly depend on the brightness of the star and the total integration time. We compare our results with contrast limits from other surveys and review the exoplanet detection limits obtained with different detection methods. For all our targets we achieve unprecedented contrast limits. Despite the high polarimetric contrasts we are not able to find any additional companions or extended polarized light sources in the data that has been taken so far.
- [32] arXiv:1911.12767 [pdf, other]
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Title: Jupiter's heavy-element enrichment expected from formation modelsComments: Accepted for publication in A&ASubjects: Earth and Planetary Astrophysics (astro-ph.EP)
The goal of this work is to investigate Jupiter's growth focusing on the amount of heavy elements accreted by the planet, and its comparison with recent structure models. Our model assumes an initial core growth dominated by pebble accretion, and a second growth phase that is characterized by a moderate accretion of both planetesimals and gas. The third phase is dominated by runaway gas accretion during which the planet becomes detached from the disk. The second and third phases are computed in detail, considering two different prescriptions for the planetesimal accretion and fits from hydrodynamical studies to compute the gas accretion in the detached phase. In order for Jupiter to consist of $\sim$20-40 $M_{\oplus}$ of heavy elements as suggested by structure models, we find that Jupiter's formation location is preferably at an orbital distance of $1\lesssim a \lesssim 10$ au once the accretion of planetesimals dominates. We find that Jupiter could accrete between $\sim$1 and $\sim$15 $M_{\oplus}$ of heavy elements during runaway gas accretion, depending on the assumed initial surface density of planetesimals and the prescription used to estimate the heavy-element accretion during the final stage of the planetary formation. This would yield an envelope metallicity of $\sim$0.5 to $\sim$3 times solar. By computing the solid accretion during the detached phase, we infer a planetary mass-metallicity ($M_P$-$M_Z$) relation of $M_Z \sim M_P^{2/5}$ when a gap in the planetesimal disk is created, and of $M_Z \sim M_P^{1/6}$ without a planetesimal gap. Our hybrid pebble-planetesimal model can account for Jupiter's bulk and atmospheric enrichment. The high bulk metallicity inferred for many giant exoplanets is difficult to explain from standard formation models. This might suggest a migration history for such highly enriched giant exoplanets and/or giant impacts after the disk's dispersal.
- [33] arXiv:1911.12769 [pdf, other]
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Title: Multifrequency study of GHz-peaked spectrum sourcesAuthors: Yu. Sotnikova, T. Mufakharov, E. Majorova, M. Mingaliev, R. Udovitskiy, N. Bursov, T. SemenovaComments: 30 pages, including 11 pages of radio spectra as the supplementary materialSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
Gigahertz-Peaked spectrum (GPS) sources are compact active galactic nuclei, presumably young precursors of bright radio sources. The study of GPS radio properties provides information about the features of synchrotron radiation in extragalactic sources. Also in applied research GPS sources are useful as compact stationary radio sources in the sky for astrometric purposes. This paper presents the results of a multifrequency GPS study based on quasi-simultaneous measurements with the RATAN-600 radio telescope during the 2006-2017. The catalog containing spectral flux densities measured at six frequencies (1.1, 2.3, 4.8, 7.7/8.2, 11.2, and 21.7 GHz) have been obtained. In addition, for the analysis of radio spectra, data from the following low-frequency surveys have been used: GLEAM (GaLactic and Extragalactic All-sky Murchison widefield array survey) and TGSS (Tata institute for fundamental research GMRT Sky Survey) and high-frequency measurements from Planck survey. A total number of 164 GPS and candidates to GPS have been identified (17 of them are new discoveries), which makes up a small fraction of GPS in the initial sample of bright AGNs, about 2%. The physical properties and formation conditions of synchrotron radiation is found to be quite different in GPS of different AGN types. The deficit of distant GPS ($z > 2$) with low maximum frequencies (less than 1 GHz) is confirmed. The existing 'size - peak frequency' anticorrelation is continuous. The continuum radio spectra are found to become statistically steeper with increasing redshift.
- [34] arXiv:1911.12772 [pdf, ps, other]
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Title: Incoherent fast variability of X-ray obscurers. The case of NGC 3783Authors: B. De Marco, T. P. Adhikari, G. Ponti, S. Bianchi, G. A. Kriss, N. Arav, E. Behar, G. Branduardi-Raymont, M. Cappi, E. Costantini, D. Costanzo, L. di Gesu, J. Ebrero, J. S. Kaastra, S. Kaspi, J. Mao, A. Markowitz, G. Matt, M. Mehdipour, R. Middei, S. Paltani, P. O. Petrucci, C. Pinto, A. Różańska, D. J. WaltonComments: Accepted for publication in A&ASubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Context. Obscuration events caused by outflowing clumps or streams of high column density, low ionisation gas, heavily absorbing the X-ray continuum, have been witnessed in a number of Seyfert galaxies. Aims. We report on the X-ray spectral-timing analysis of the December 2016 obscuration event in NGC 3783, aimed at probing variability of the X-ray obscurer on the shortest possible timescales. The main goals of this study are to obtain independent constraints on the density, and ultimately on the distance of the obscuring gas, as well as to characterise the impact of variable obscuration on the observed X-ray spectral-timing characteristics of Seyfert galaxies. Methods. We carried out a comparative analysis of NGC 3783 during unobscured (using archival 2000-2001 XMM-Newton data) and obscured states (using XMM-Newton and NuSTAR data from the 2016 observational campaign). The timescales analysed range between ten hours and about one hour. This study was then generalized to discuss the signatures of variable obscuration in the X-ray spectral-timing characteristics of Seyfert galaxies as a function of the physical properties of the obscuring gas. Results. The X-ray obscurer in NGC 3783 is found to vary on timescales between about one hour to ten hours. This variability is incoherent with the variations of the X-ray continuum. A fast response (on timescales shorter than about 1.5 ks) of the ionisation state of the obscuring gas to the short timescale variability of the primary X-ray continuum provides a satisfactory interpretation of all the observed X-ray spectral-timing properties. This study enabled us to put independent constraints on the density and location of the obscuring gas. We found the gas to have a density of $n_{e}> 7.1 \times 10^7 \rm{cm^{-3}}$, consistent with being part of the broad line region.
- [35] arXiv:1911.12788 [pdf, other]
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Title: Revisiting the cosmic-ray induced Venusian radiation dose in the context of habitabilitySubjects: Earth and Planetary Astrophysics (astro-ph.EP); Space Physics (physics.space-ph)
The Atmospheric Radiation Interaction Simulator (AtRIS) was used to model the altitude-dependent Venusian absorbed dose and the Venusian dose equivalent. For the first time, we modeled the dose rates for different shape-, size-, and composition-mimicking detectors (phantoms): a CO$_2$-based phantom, a water-based microbial cell, and a phantom mimicking human tissue. Based on a new model approach, we give a reliable estimate of the altitude-dependent Venusian radiation dose in water-based microorganisms here for the first time. These microorganisms are representative of known terrestrial life. We also present a detailed analysis of the influence of the strongest ground-level enhancements measured at the Earth's surface, and of the impact of two historic extreme solar events on the Venusian radiation dose. Our study shows that because a phantom based on Venusian air was used, and because furthermore, the quality factors of different radiation types were not taken into account, previous model efforts have underestimated the radiation hazard for any putative Venusian cloud-based life by up to a factor of five. However, because we furthermore show that even the strongest events would not have had a hazardous effect on putative microorganisms within the potentially habitable zone (51 km - 62 km), these differences may play only a minor role.
- [36] arXiv:1911.12792 [pdf, other]
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Title: Effects of Magnetic Field Loops on the Dynamics of Advective Accretion Flows and Jets around a Schwarzschild BlackholeComments: 16 pages, 16 figures, accepted in ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Magnetic fields advected along with low angular momentum accretion flows predominantly become toroidal due to the strong azimuthal velocity close to a black hole. We study self-consistently the movements of these flux tubes inside an advective disc and how they dynamically influence the flow. We find that the centrifugal barrier slows down the radial motion of the flux tubes. In this case, the large magnetic flux tubes with a significant drag force escape along the vertical axis due to buoyancy. Magnetic pressure rises close to the black hole and together with the centrifugal force, it combats gravity. The tug-of-war among these forces causes the centrifugal pressure supported shock to oscillate radially. We study the effects of successive injection of flux tubes and find how the flux tube could be trapped inside the disc in regions of highest entropy. Most interestingly, the shock wave remains at its average location and is not destroyed. We show that the toroidal field loops contribute significantly to collimate and accelerate the outflows from the centrifugal barrier and suggest this mechanism to be a way to collimate and accelerate jets.
- [37] arXiv:1911.12812 [pdf]
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Title: Models of the Mass-Ejection Histories of pre Planetary Nebulae, IV. Magnetized Winds and the Origins of Jets, Bullets, and FLIERsComments: accepted by ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The influences and consequences of toroidal magnetic fields in shaping the visible lobes of pre planetary nebulae ("prePNe") are explored in this, the last of a series of papers of parameter studies of prePN evolution. To probe these influences we start with the steady, diverging, and field-free wind model of our previous papers and add weak to moderate toroidal fields to the winds in order to generate arrays of outcomes after 500 y, after which the structures grow almost homologously. As expected, toroidal fields in the stellar winds invariably form very thin and dense axial features whose structure is best described as a thin cold jet with an ultra-dense and neutral leading knot, or "bullet", at its tip. The speed of the leading knot depends only on the density contrast (the ratio of injected to ambient gas densities at the nozzle) and wind injection speed, but not on the field strength or opening angle. The lobes formed by the ram pressure of the winds take a variety of forms and sizes that depend primarily on the geometric structure of the injected gas and the density contrast. About 20% of the HST images of prePNe show the unique signatures of shaping by toroidal fields. Pairs of low-ionization knots seen along the major axis of fully ionized PNe, often called "FLIERs" are easily explained as the very dense, cold , and neutral remnants of magnetically formed knots.
- [38] arXiv:1911.12818 [pdf, ps, other]
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Title: The magnetic field and accretion regime of CI TauAuthors: JF Donati, J Bouvier, SH Alencar, C Moutou, L Malo, M Takami, F Menard, C Dougados, GA Hussain, the MaTYSSE collaborationComments: MNRAS, in press (10 pages, 6 figures, 2 tables)Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
This paper exploits spectropolarimetric data of the classical T Tauri star CI Tau collected with ESPaDOnS at the Canada-France-Hawaii Telescope, with the aims of detecting and characterizing the large-scale magnetic field that the star hosts, and of investigating how the star interacts with the inner regions of its accretion disc through this field. Our data unambiguously show that CI Tau has a rotation period of 9.0d, and that it hosts a strong, mainly poloidal large-scale field. Accretion at the surface of the star concentrates within a bright high-latitude chromospheric region that spatially overlaps with a large dark photospheric spot, in which the radial magnetic field reaches -3.7kG. With a polar strength of -1.7kG, the dipole component of the large-scale field is able to evacuate the central regions of the disc up to about 50% of the co-rotation radius (at which the Keplerian orbital period equals the stellar rotation period) throughout our observations, during which the average accretion rate was found to be unusually high. We speculate that the magnetic field of CI Tau is strong enough to sustain most of the time a magnetospheric gap extending to at least 70% of the co-rotation radius, which would explain why the rotation period of CI Tau is as long as 9d. Our results also imply that the 9d radial velocity (RV) modulation that CI Tau exhibits is attributable to stellar activity, and thus that the existence of the candidate close-in massive planet CI Tau b to which these RV fluctuations were first attributed needs to be reassessed with new evidence.
- [39] arXiv:1911.12828 [pdf, other]
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Title: Discovery of a Powerful >10^61 erg AGN Outburst in Distant Galaxy Cluster SPT-CLJ0528-5300Authors: Michael S. Calzadilla, Michael McDonald, Matthew Bayliss, Bradford A. Benson, Lindsey E. Bleem, Mark Brodwin, Alastair C. Edge, Benjamin Floyd, Nikhel Gupta, Julie Hlavacek-Larrondo, Brian R. McNamara, Christian L. ReichardtComments: Accepted to ApJL. 8 pages, 5 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)
We present ~103 ks of Chandra observations of the galaxy cluster SPT-CLJ0528-5300 (SPT0528, z=0.768). This cluster harbors the most radio-loud (L_1.4GHz = 1.01 x 10^33 erg/s/Hz) central AGN of any cluster in the South Pole Telescope (SPT) SZ survey with available X-ray data. We find evidence of AGN-inflated cavities in the X-ray emission, which are consistent with the orientation of the jet direction revealed by ATCA radio data. The combined probability that two such depressions -- each at ~1.4-1.8sigma significance, oriented ~180 degrees apart and aligned with the jet axis -- would occur by chance is 0.1%. At >10^61 erg, the outburst in SPT0528 is among the most energetic known in the universe, and certainly the most powerful known at z>0.25. This work demonstrates that such powerful outbursts can be detected even in shallow X-ray exposures out to relatively high redshifts (z~0.8), providing an avenue for studying the evolution of extreme AGN feedback. The ratio of the cavity power (P_cav = 9.4+/-5.8 x 10^45 erg/s) to the cooling luminosity (L_cool = 1.5+/-0.5 x 10^44 erg/s) for SPT0528 is among the highest measured to date. If, in the future, additional systems are discovered at similar redshifts with equally high P_cav/L_cool ratios, it would imply that the feedback/cooling cycle was not as gentle at high redshifts as in the low-redshift universe.
- [40] arXiv:1911.12830 [pdf, other]
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Title: Uranus in Northern Mid-Spring: Persistent Atmospheric Temperatures and Circulations Inferred from Thermal ImagingAuthors: Michael T. Roman, Leigh N. Fletcher, Glenn S. Orton, Naomi Rowe-Gurney, Patrick G. J. IrwinComments: 22 pages, 17 figures; Accepted for publication in The Astronomical JournalSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We present results from mid-infrared imaging of Uranus at wavelengths of 13.0 micron and 18.7 micron, sensing emission from the stratosphere and upper troposphere, acquired using the VISIR instrument at the Very Large Telescope (VLT), September 4-October 20, 2018. Using a combination of inverse and forward modeling, we analyze these northern mid-spring (L_s~46) images and compare them to archival data to assess seasonal changes since the 1986 southern solstice and subsequent equinox. We find the data are consistent with little change (< 0.3 K) in the upper tropospheric temperature structure, extending the previous conclusions of Orton et al (2015) well past equinox, with only a subtle increase in temperature at the emerging north pole. Additionally, spatial-temporal variations in 13 micron stratospheric emission are investigated for the first time, revealing meridional variation and a hemispheric asymmetry not predicted by models. Finally, we investigate the nature of the stratospheric emission and demonstrate that the observed distribution appears related and potentially coupled to the underlying tropospheric emission six scale heights below. The observations are consistent with either mid-latitude heating or an enhanced abundance of acetylene. Considering potential mechanisms and additional observations, we favor a model of acetylene enrichment at mid-latitudes resulting from an extension of the upper-tropospheric circulation, which appears capable of transporting methane from the troposphere, through the cold trap, and into the stratosphere for subsequent photolysis to acetylene.
- [41] arXiv:1911.12831 [pdf, other]
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Title: Type IIP Supernova Progenitors II: Stellar Mass and Obscuration by the Dust in the Circumstellar MediumComments: 14 pages, 6 Figures, 2 Tables, Accepted for publication in The Astrophysical JournalSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
It has been well established from a variety of observations that red supergiants (RSGs) loose a lot of mass in stellar wind. Dust formed in this emitted gas over a few decades before core-collapse can lead to substantial extinction and obscure the intrinsic luminosity of the progenitor RSG. This may lead to a difficulty in determining the range of progenitor masses that lead to the different classes of supernovae. Even the nearby, well studied supernovae with pre-explosion observations, such as SN 2013ej may suffer from this uncertainty in the progenitor mass. We explore here two different masses proposed for its progenitor. We compute their pre-supernova characteristics using Modules for Experiments in Stellar Astrophysics (MESA). We show that a non-rotating star with the initial mass of 26 M$_{\odot}$ would require a considerable amount of circum-stellar medium (A$_V \sim$ 3) to obscure its high luminosity given the observed pre-explosion magnitudes detected by the Hubble Space Telescope (HST). Such a high value of visual extinction appears to be inconsistent with that derived for SN 2013ej as well as SN 2003gd in the same host galaxy M74. In contrast, the evolutionary models of lower mass (13 M$_{\odot}$) star are easily accommodated within the observed HST magnitudes. Some of the 26 M$_{\odot}$ simulations show luminosity variation in the last few years which could be discriminated by high cadence and multi-band monitoring of supernova candidates in nearby galaxies. We demonstrate that our calculations are well-resolved with adequate zoning and evolutionary time-steps.
- [42] arXiv:1911.12832 [pdf, other]
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Title: A lack of evolution in the very bright-end of the galaxy luminosity function from z = 8-10Authors: R.A.A. Bowler, M.J. Jarvis, J.S. Dunlop, R.J. McLure, D.J. McLeod, N.J. Adams, B. Milvang-Jensen, H.J. McCrackenComments: 17 pages, 10 figures and 7 tables in the main text, plus additional figures in the appendix. Submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We utilize deep near-infrared survey data from the UltraVISTA fourth data release (DR4) and the VIDEO survey, in combination with overlapping optical and Spitzer data, to search for bright star-forming galaxies at $z \gtrsim 7.5$. Using a full photometric redshift fitting analysis applied to the $\sim 6\,{\rm deg}^2$ of imaging searched, we find 27 Lyman-break galaxies (LBGs), including 20 new sources, with best-fitting photometric redshifts in the range $7.5 < z < 9.1$. From this sample we derive the rest-frame UV luminosity function (LF) at $z = 8$ and $z = 9$ out to extremely bright UV magnitudes ($M_{\rm UV} \simeq -23$) for the first time. We find an excess in the number density of bright galaxies in comparison to the typically assumed Schechter functional form derived from fainter samples. Combined with previous studies at lower redshift, our results show that there is little evolution in the number density of very bright ($M_{\rm UV} \sim -23$) LBGs between $z \simeq 5$ and $z\simeq 9$. The tentative detection of an LBG with best-fit photometric redshift of $z = 10.9 \pm 1.0$ in our data is consistent with the derived evolution. We show that a double power-law fit with a brightening characteristic magnitude ($\Delta M^*/\Delta z \simeq -0.5$) and a steadily steepening bright-end slope ($\Delta \beta/\Delta z \simeq -0.5$) provides a good description of the $z > 5$ data over a wide range in absolute UV magnitude ($-23 < M_{\rm UV} < -17$). We postulate that the observed evolution can be explained by a lack of mass quenching at very high redshifts in combination with increasing dust obscuration within the first $\sim 1 \,{\rm Gyr}$ of galaxy evolution.
- [43] arXiv:1911.12833 [pdf, ps, other]
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Title: Emission from a Pulsar Wind Nebula: Application to the Persistent Radio Counterpart of FRB 121102Comments: 10 pages, 4 figures, 1 table. Published in the Astrophysical Journal on Nov. 11, 2019Journal-ref: The Astrophysical Journal 885 (2019) 149Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The properties of fast radio bursts (FRBs) indicate that the physical origin of this type of astrophysical phenomenon is related to neutron stars. The first detected repeating source, FRB 121102, is associated with a persistent radio counterpart. In this paper, we propose that this radio counterpart could arise from a pulsar wind nebula powered by a magnetar without surrounding supernova ejecta. Its medium is a stratified structure produced by a progenitor wind. The model parameters are constrained by the spectrum of the counterpart emission, the size of the nebula, and the large but decreasing rotation measure (RM) of the repeating bursts. In addition, the observed dispersion measure is consistent with the assumption that all of the RM comes from the shocked medium.
- [44] arXiv:1911.12840 [pdf]
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Title: Meteoroid Stream Formation Due to the Extraction of Space Resources from AsteroidsComments: Conference paper for the 1st International Orbital Debris Conference, December 9-12, 2019, Sugar Land, TX, USASubjects: Earth and Planetary Astrophysics (astro-ph.EP)
[Abridged] Asteroid mining is not necessarily a distant prospect. Hayabusa2 and OSIRIS-REx have recently rendezvoused with near-Earth asteroids and will return samples to Earth. While there is significant science motivation for these missions, there are also resource interests. Space agencies and commercial entities are particularly interested in ices and water-bearing minerals that could be used to produce rocket fuel in space. The internationally coordinated roadmaps of major space agencies depend on utilizing the natural resources of such celestial bodies. Several companies have already created plans for intercepting and extracting water and minerals from near-Earth objects, as even a small asteroid could have high economic worth. However, the low surface gravity of asteroids could make the release of mining waste and the subsequent formation of debris streams a consequence of asteroid mining. Strategies to contain material during extraction could still eventually require the purposeful jettison of waste to avoid managing unwanted mass. Using simulations, we explore the formation of mining debris streams by integrating particles released from four select asteroids. Radiation effects are included, and a range of debris sizes are explored. The simulation results are used to investigate the timescales for debris stream formation, the sizes of the streams, and the meteoroid fluxes compared with sporadic meteoroids. We find that for prodigious mining activities resulting in the loss of a few percent of the asteroid's mass or more, it is possible to produce streams that exceed the sporadic flux during stream crossing for some meteoroid sizes. The result of these simulations are intended to highlight potential unintended consequences that could result from NewSpace activity, which could help to inform efforts to develop international space resource guidelines.
- [45] arXiv:1911.12856 [pdf, ps, other]
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Title: On producers of cosmic organic compounds: exploring the boron abundance in lithium-rich K giant starsComments: 5 pages, 4 figures, published in the Proceedings of the IAU Symposium 332 "Astrochemistry VII - Through the Cosmos from Galaxies to Planets", Puerto Varas, Chile, March 20-24, 2017Journal-ref: Proceedings of the International Astronomical Union, IAU Symposium, Volume 332, pp. 237-241 (2018)Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
The element boron belongs, together with lithium and beryllium, to a known trio of important elements for the study of evolutionary processes in low mass stars. Because B is the least fragile of this trio to be destroyed in the stellar interiors, it can be used to test if the Li enrichment is of planetary origin. Here, for the first time, boron lines are examined in the UV for four giants with different degrees of large Li enrichment by means of observations with the Hubble telescope. Two main results are found in our study. One is that to first approximation B abundances appear not to be in excess, invalidating the planet engulfment mechanism. The second one is that the two stars with very large Li abundances present emission lines indicating that quite strong active chromospheres are acting in these very Li-rich giants. These new results obtained from the UV complement our recent studies in the mid-IR (de la Reza et al. 2015) where strong emission-line features of organic material were found in the spectra of some Li-rich stars.
- [46] arXiv:1911.12881 [pdf, ps, other]
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Title: The Radio Synchrotron Background -- A Cosmic ConundrumAuthors: J. SingalComments: 6 pages, 2 figures. To Appear in "Particle Physics at the Year of the 150th Anniversary of Mendeleev's Periodic Table of Chemical Elements," A. Studenikin, Ed. (Proceedings of the 19th Lomonosov Conference on Elementary Particle Physics)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
It has recently become apparent that the background level of diffuse radio emission on the sky is significantly higher than the level that can result from known extragalactic radio source classes or our Galaxy given our current understanding of its large-scale structure.~ In contrast to the more well-known and well-constrained cosmological and astrophysical backgrounds at microwave, infrared, optical/UV, X-ray, and gamma-ray wavelengths, this ``radio synchrotron background'' at radio wavelengths provides clear motivation for considering the possibilities of new astrophysical sources and new particle-based emission mechanisms.
- [47] arXiv:1911.12888 [pdf, other]
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Title: Compact groups from semi-analytical models of galaxy formation -- I: a comparative study of frequency and natureAuthors: Eugenia Diaz-Gimenez (1), Antonela Taverna (1), Ariel Zandivarez (1), Gary Mamon (2) ((1) OAC/UNC - IATE/CONICET/UNC - (2) IAP)Comments: 17 pages, 10 figures, 4 tables, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
Compact groups (CGs) of galaxies are defined as isolated and dense galaxy systems that appear to be a unique site of multiple galaxy interactions. Semi-analytical models of galaxy formation (SAMs) are a prime tool to understand CGs. We investigate how the frequency and the three-dimensional nature of CGs depends on the SAM and its underlying cosmological parameters. Extracting 9 lightcones of galaxies from 5 different SAMs and selecting CGs as in observed samples, we find that the frequency and nature of CGs depends strongly on the cosmological parameters. Moving from the WMAP1 to the WMAP7 and Planck cosmologies (increasing density of the Universe and decreasing normalisation of the power spectrum), the space density of CGs is decreased by a factor 2.5, while the fraction of CGs that are physically dense falls from 50 to 35 percent. The lower $\sigma_8$ leads to fewer dense groups, while the higher $\Omega_{\rm m}$ causes more chance alignments. However, with increased mass and spatial resolution, the fraction of CGs that are physically dense is pushed back up to 50 percent. The intrinsic differences in the SAM recipes also lead to differences in the frequency and nature of CGs, particularly those related to how SAMs treat orphan galaxies. We find no dependence of CG properties on the flux limit of the mock catalogues nor on the waveband in which galaxies are selected. One should thus be cautious when interpreting a particular SAM for the frequency and nature of CGs.
- [48] arXiv:1911.12890 [pdf, other]
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Title: Decoding Cosmological Information in Weak-Lensing Mass Maps with Generative Adversarial NetworksComments: 19 pages, 17 figures, 1 tableSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM); Data Analysis, Statistics and Probability (physics.data-an); Machine Learning (stat.ML)
Galaxy imaging surveys enable us to map the cosmic matter density field through weak gravitational lensing analysis. The density reconstruction is compromised by a variety of noise originating from observational conditions, galaxy number density fluctuations, and intrinsic galaxy properties. We propose a deep-learning approach based on generative adversarial networks (GANs) to reduce the noise in the weak lensing map under realistic conditions. We perform image-to-image translation using conditional GANs in order to produce noiseless lensing maps using the first-year data of the Subaru Hyper Suprime-Cam (HSC) survey. We train the conditional GANs by using 30000 sets of mock HSC catalogs that directly incorporate observational effects. We show that an ensemble learning method with GANs can reproduce the one-point probability distribution function (PDF) of the lensing convergence map within a $0.5-1\sigma$ level. We use the reconstructed PDFs to estimate a cosmological parameter $S_{8} = \sigma_{8}\sqrt{\Omega_{\rm m0}/0.3}$, where $\Omega_{\rm m0}$ and $\sigma_{8}$ represent the mean and the scatter in the cosmic matter density. The reconstructed PDFs place tighter constraint, with the statistical uncertainty in $S_8$ reduced by a factor of $2$ compared to the noisy PDF. This is equivalent to increasing the survey area by $4$ without denoising by GANs. Finally, we apply our denoising method to the first-year HSC data, to place $2\sigma$-level cosmological constraints of $S_{8} < 0.777 \, ({\rm stat}) + 0.105 \, ({\rm sys})$ and $S_{8} < 0.633 \, ({\rm stat}) + 0.114 \, ({\rm sys})$ for the noisy and denoised data, respectively.
- [49] arXiv:1911.12894 [pdf, other]
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Title: BEC and antiparticles in a magnetized neutral vector boson gas at any temperatureComments: 8 pages, 4 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
We study the thermodynamic properties of a relativistic magnetized neutral vector boson gas at any temperature. We analyse the effect of temperature as well as antiparticles in Bose-Einstein condensation. Astrophysical implications are discussed.
- [50] arXiv:1911.12897 [pdf, other]
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Title: VVV Survey Microlensing: the Galactic Latitude DependenceComments: 11 pages, 8 figures, Accepted in The Astrophysical JournalSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We search for microlensing events in fields along the Galactic minor axis, ranging from the Galactic center to -3.7<b< 3.9 deg., using the VVV survey near-IR photometry. The new search is made across VVV tiles b291, b305, b319, b347, b361 and b375, covering a total area of about 11.5 deg.^2. We find a total of N=238 new microlensing events in this new area, N=74 of which are classified as bulge red clump (RC) giant sources. Combining them with N=122 events that we had previously reported in the Galactic center (VVV tile b333), allows us to study the latitude distribution of the microlensing events reaching the Galactic plane at b=0^0 for the first time. We find a very strong dependence of the number of microlensing events with Galactic latitude, number that increases rapidly towards the Galactic center by one order of magnitude from |b|=2 deg. to b=0 deg. with a much steeper gradient than with Galactic longitude. The microlensing event population shows a flattened distribution (axial ratio b/a \approx 1.5). The final sample shows a shorter mean timescale distribution than the Galactic plane sample for both, the complete population and RC stars.
- [51] arXiv:1911.12901 [pdf, other]
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Title: Distribution of radio spectral slopes of galaxies in optical diagnostic diagramsComments: 6 pages, 3 figures, 2 tables; submitted as a conference contribution (39. PTA meeting; Olsztyn, September 9-12, 2019) to the Polish Astronomical Society ProceedingsSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
For about 500 intermediate-redshift sources ($0.04<z<0.4$), whose radio flux densities at $1.4\,{\rm GHz}$ are larger than 10 mJy, we performed additional observations at 4.85 GHz and 10.45 GHz using 100-m Effelsberg telescope. Our radio-optical galaxies are located preferentially in the Composite and AGN spectral classes in the narrow line optical diagnostic diagrams (ODD). In the analysis, we focused on the distribution of radio spectral indices of radio synchrotron power-law profiles, $S_{\nu}\propto \nu^{+\alpha}$, in the ODDs. Using different analysis techniques, both observationally motivated and using machine learning, we found three distinct groups--clusters in the radio loudness, [OIII]/H$\beta$ ratio, and spectral index volume: (1) sources with steep radio spectral index, large radio loudness and large [OIII]/H$\beta$ ratio; (2) sources with flat radio spectral index, intermediate radio loudness and lower [OIII]/H$\beta$ ratio; (3) sources with inverted radio spectral index, low radio loudness and low [OIII]/H$\beta$. The groups (1), (2), and (3) are located along the Seyfert-LINER spectral classes towards lower ionization ratios in the ODDs and hence can represent different activity cycles/accretion modes of AGNs, which could be in some cases associated with different merger stages.
- [52] arXiv:1911.12923 [pdf, other]
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Title: Single particle triboelectrification of Titan sand analogsComments: 25 pages, 5 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Soft Condensed Matter (cond-mat.soft)
Sand electrification is important for aeolian sediment transportation on terrestrial bodies with silicate sand as the main sediment composition. However, it has not been thoroughly studied for icy bodies such as Titan with organic sand as the main dune-forming material. We used the colloidal probe atomic force microscopy (AFM) technique to study triboelectric charging processes using Titan and Earth sand analogs. We found that it is easy to generate triboelectric charges between naphthalene (a simple aromatic hydrocarbon), polystyrene (an aromatic hydrocarbon polymer), and borosilicate glass (Earth silicate sand analog). Strong electrostatic forces can be measured after contact and/or tribocharging. In contrast, tholin, a complex organic material, does not generate any detectable electrostatic forces with contact or tribocharging within the detection limit of the instrument. If Titan sand behaves more like tholin, this indicates that the tribocharging capacity of Titan sand is much weaker than Earth silicate sand and much less than previously measured by Mendez-Harper et al., (2017), where only simple organics were used for Titan sand analogs. Thus, triboelectrification may not contribute to increasing interparticle forces between sand particles on Titan as much as on Earth. Interparticle forces generated by other electrostatic processes or other interparticle forces such as van der Waals and capillary cohesion forces could be the dominant interparticle forces that govern Titan sand formation and sediment transportation on the surface. Titan sand is also unlikely to produce large electrical discharge through tribocharging to affect future missions to Titan's surface.
- [53] arXiv:1911.12958 [pdf, other]
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Title: Feasibility of Observing Gamma-ray Polarization from Cygnus X-1 Using a CubeSatAuthors: Chien-Ying Yang, Yi-Chi Chang, Hung-Hsiang Liang, Che-Yen Chu, Jeng-Lun Chiu, Chih-Hsun Lin, Philippe Laurent, Jerome Rodriguez, Hsiang-Kuang ChangComments: 8 pages, 6 figures, submitted to Astronomical JournalSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex)
Instruments own on CubeSats are small. Meaningful applications of CubeSats in astronomical observations rely on the choice of a particular subject that is feasible for CubeSats. Here we report the result of a feasibility study for observing gamma-ray polarization from Cygnus X-1 using a small Compton polarimeter on board a 3U CubeSat. Silicon detectors and cerium bromide scintillators were employed in the instrument models that we discussed in this study. Through Monte Carlo simulations with Geant4-based MEGALib package, we found that, with 10-Ms observation time in a low earth orbit, the minimum detectable polarization degree can be lower than 10% in 100 - 250 keV, 20% in 250 - 400 keV, and 65% in 400 - 2000 keV, if the instrument trigger energy threshold is set at 40 keV. A 3U CubeSat dedicated to observing Cygnus X-1 can therefore yield useful information on the polarization state of gamma-ray emissions from the brightest persistent X-ray black-hole binary in the sky.
- [54] arXiv:1911.12967 [pdf, other]
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Title: The ATLAS 9.0 GHz Survey of the Extended Chandra Deep Field South: The Faint 9.0 GHz Radio PopulationComments: 17 pages, 12 figures. Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present a new image of the 9.0 GHz radio emission from the extended Chandra Deep Field South. A total of 181 hours of integration with the Australia Telescope Compact Array has resulted in a 0.276 square degree image with a median sensitivity of $\sim$20 $\mu$Jy/beam rms, for a synthesised beam of 4.0 $\times$ 1.3 arcsec. We present a catalogue of the 9.0 GHz radio sources, identifying 70 source components and 55 individual radio galaxies. Source counts derived from this sample are consistent with those reported in the literature. The observed source counts are also generally consistent with the source counts from simulations of the faint radio population. Using the wealth of multiwavelength data available for this region, we classify the faint 9 GHz population and find that 91% are radio loud AGN, 7% are radio quiet AGN and 2% are star forming galaxies. The 9.0 GHz radio sources were matched to 5.5 and 1.4 GHz sources in the literature and we find a significant fraction of flat or inverted spectrum sources, with 36% of the 9 GHz sources having $\alpha_{5.5GHz}^{9.0GHz}$ $>$ -0.3 (for $S \propto \nu^\alpha$). This flat or inverted population is not well reproduced by current simulations of radio source populations.
- [55] arXiv:1911.12977 [pdf, other]
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Title: Positron Excess from Cosmic Ray Interactions in Galactic Molecular CloudsComments: 20 pages, 5 figures, 6 tablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The recent data on cosmic ray positron flux measured near the Earth by the \textit{Alpha Magnetic Spectrometer} (AMS-02) experiment extends to TeV energy. The positron flux measured in GeV$^2$ m$^{-2}$ sec$^{-1}$ sr$^{-1}$ rises with energy and shows a peak near a few hundred GeV. This rising positron flux cannot be explained by interactions of cosmic rays with interstellar hydrogen gas. Due to the progress in multi-wavelength astronomy, many new Galactic Molecular Clouds (GMCs) have been discovered in our Galaxy recently. We use the updated list of GMCs, which are distributed in the Galactic plane, to find the secondary positrons produced in them in interactions of cosmic rays with molecular hydrogen. Moreover, by analysing the Fermi LAT data, new GMCs have been discovered away from the Galactic plane. We also include some of these GMCs closest to the Earth where cosmic ray interactions are producing secondaries. After including these GMCs we show that the positron excess can be mostly well explained, with a small contribution from unknown extra component near the peak.
- [56] arXiv:1911.12980 [pdf, other]
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Title: CCD UBV(RI)KC Photometry of the Open Clusters Juchert 9 and Berkeley 97Authors: İnci Akkaya Oralhan, Raúl Michel, Yonca Karslı, Hikmet Çakmak, Hwankyung Sung, Yüksel KarataşComments: 10 pages, 20 figures and 6 tables, accepted to publish in Astronomische NachrichtenSubjects: Astrophysics of Galaxies (astro-ph.GA)
The CCD UBV(RI)KC photometry of the poorly studied open clusters Juchert 9 (Juc 9) and Berkeley 97 (Be 97), which are observed with the 0.84 m telescope at the San Pedro M\'artir National Observatory, M\'exico has been analysed. For the likely cluster members, we determined the reddenings, E(B-V)=0.82 +- 0.04 (Juc 9) and E(B-V)=0.87 +- 0.05 (Be 97), from the early type stars. Our distance moduli/distances for only (B - V) colour are (Vo-Mv , d(kpc)) = (13.40 +- 0.10, 4.8 +- 0.2 kpc) (Juc 9) and (12.40 +- 0.12, 3.0 +- 0.2 kpc) (Be 97), respectively. The Gaia DR2 distances are d = 4.5 +- 1.2 kpc (Juc 9) and d = 3.1 +- 0.7 kpc (Be 97) from the median parallaxes with relative parallaxes < 0.20, which are in good agreement with the photometric distances within the uncertainties. The solar abundance PARSEC isochrones give us the intermediate ages, 30 +- 10 Myr for Juc 9 and 100 +- 30 Myr for Be 97.
- [57] arXiv:1911.12991 [pdf, other]
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Title: The partial banana mapping: a robust linear method for impact probability estimationAuthors: Dmitrii E. VavilovComments: 7 pages, 3 figures, 2 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
This paper presents a robust linear method for impact probability estimation of near-Earth asteroids with the Earth. This method is a significantly modified and improved method, which uses a special curvilinear coordinate system associated with the nominal orbit of an asteroid. One of the coordinates of this system is the mean anomaly in the osculating orbit of an asteroid. A normal distribution of errors of coordinates and velocities of this system is assumed. Because of the usage of the curvilinear coordinate system, the fact that the confidence region is curved and stretched mainly along the nominal asteroid orbit is taken into account. On the main axis of the curvilinear confidence ellipsoid the virtual asteroid, which is the closest to the Earth, is found. The part of the curvilinear confidence ellipsoid, around the found virtual asteroid, is obtained and mapped on to its target plane. The impact probability is calculated as the probability of the asteroid being in the region of the found virtual asteroid multiplied by the probability of a collision of the found virtual asteroid with the Earth. This approach is shown to give more accurate and trustworthy results than the target plane method.
- [58] arXiv:1911.12998 [pdf, other]
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Title: Detailed Calculations of the Efficiency of Planetesimal Accretion in the Core-Accretion ModelComments: submitted to AAS, comments are welcomeSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We present results of a detailed study of the rate of the accretion of planetesimals by a growing proto-Jupiter in the core-accretion model. Using a newly developed code, we accurately combine a detailed three-body trajectory calculation with gas drag experienced during the passage of planetesimals in the protoplanet's envelope. We find that the motion of planetesimals is excited to the extent that encounters with the proto-planetary envelope become so fast that ram pressure breaks up the planetesimals in most encounters. As a result, the accretion rate is largely independent of the planetesimal size and composition. For the case we explored of a planet forming at 5.2 AU from the Sun in a disk with a solid surface density of 6 g/cm^2 (Lozovsky et al. 2017) the accretion rate we compute differs in several respects from that assumed by those authors. We find that only 4-5 M_Earth is accreted in the first 1.5x10^6 years before the onset of rapid gas accretion. Most of the mass, some 10 M_Earth, is accreted simultaneously with this rapid gas accretion. In addition, we find that the mass accretion rate remains small, but non-zero for at least a million years after this point, and an additional 0.3-0.4 M_Earth is accreted during that time. This late accretion, together with a rapid infall of gas could lead to the accreted material being mixed throughout the outer regions, and may account for the enhancement of high-Z material in Jupiter's envelope.
- [59] arXiv:1911.12999 [pdf, other]
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Title: Influences of three-dimensional gas flow induced by protoplanets on pebble accretion --$\rm\,I\,$. shear regimeComments: 19 pages, 13 figures, Accepted for publication in Astronomy and Astrophysics (A&A)Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
The pebble accretion model has the potential to explain the formation of various types of planets. A growing planet embedded in a disk induces three-dimensional (3D) gas flow, which may influence pebble accretion. In this study, we investigate the influence of the 3D planet-induced gas flow on pebble accretion. Assuming a non-isothermal, inviscid gas disk, we perform 3D hydrodynamical simulations on the spherical polar grid. Then we numerically integrate the equation of motion of pebbles in 3D using hydrodynamical simulations data. We find that the trajectories of pebbles in the planet-induced gas flow differ significantly from those in the unperturbed shear flow for a wide range of pebble sizes investigated (${\rm St}=10^{-3}$--$10^{0}$, where ${\rm St}$ is the Stokes number). The horseshoe flow and outflow of the gas alter the motion of the pebbles, which leads to the reduction of the width of the accretion window, $w_{\rm acc}$, and the accretion cross section, $A_{\rm acc}$. On the other hand, the changes in trajectories also cause an increase in relative velocity of pebbles to the planet, which offsets the reduction of $w_{\rm acc}$ and $A_{\rm acc}$. As a consequence, in the Stokes regime, the accretion probability of pebbles, $P_{\rm acc}$, in the planet-induced gas flow is comparable to that in the unperturbed shear flow except when the Stokes number is small, ${\rm St}\sim10^{-3}$, in 2D accretion, or when the thermal mass of the planet is small, $m=0.03$ in 3D accretion. In contrast, in the Epstein regime, $P_{\rm acc}$ in the planet-induced gas flow becomes smaller than that in the shear flow in the Stokes regime in both 2D and 3D accretion, regardless of assumed ${\rm St}$ and $m$. Our results suggest that the 3D planet-induced gas flow may be helpful to explain the distribution of exoplanets as well as the architecture of the solar system.
- [60] arXiv:1911.13005 [pdf]
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Title: Evidence of ammonium salts in comet 67P as explanation for the nitrogen depletion in cometary comaeAuthors: K. Altwegg, H. Balsiger, J.-J. Berthelier, C. Briois, M. Combi, H. Cottin, J. De Keyser, F. Dhooghe, B. Fiethe, S. A. Fuselier, T. I. Gombosi, N. Hänni, M. Rubin, M. Schuhmann, I. Schroeder, T. Sémon, S. WampflerSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cometary comae are generally depleted in nitrogen. The main carriers for volatile nitrogen in comets are NH3 and HCN. It is known that ammonia readily combines with many acids like e.g. HCN, HNCO, HCOOH, etc. encountered in the interstellar medium as well as in cometary ice to form ammonium salts (NH4+X-) at low temperatures. Ammonium salts, which can play a significant role in prebiotic chemistry, are hard to detect in space as they are unstable in the gas phase and their infrared signature is often hidden by thermal radiation or by e.g. OH in minerals. Here we report the presence of all possible sublimation products of five different ammonium salts at comet 67P/Churyumov-Gerasimenko measured by the ROSINA instrument on Rosetta. The relatively high sublimation temperatures of the salts leads to an apparent lack of volatile nitrogen in the coma. This then also explains the observed trend of higher NH3/H2O ratios with decreasing perihelion distances in comets.
- [61] arXiv:1911.13017 [pdf, ps, other]
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Title: The detection of dust gap-ring structure in the outer region of the CR Cha protoplanetary diskAuthors: Seongjoong Kim, Sanemichi Takahashi, Hideko Nomura, Takashi Tsukagoshi, Seokho Lee, Takayuki Muto, Ruobing Dong, Yasuhiro Hasegawa, Jun Hashimoto, Kazuhiro Kanagawa, Akimasa Kataoka, Mihoko Konishi, Hauyu Baobab Liu, Munetake Momose, Michael Sitko, Kengo TomidaComments: 21 pages, figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We observe the dust continuum at 225 GHz and CO isotopologue (12CO, 13CO, and C18O) J=2-1 emission lines toward the CR Cha protoplanetary disk using the Atacama Large Millimeter/Submillimeter Array (ALMA). The dust continuum image shows a dust gap-ring structure in the outer region of the dust disk. A faint dust ring is also detected around 120 au beyond the dust gap. The CO isotopologue lines indicate that the gas disk is more extended than the dust disk. The peak brightness temperature of the 13CO line shows a small bump around 130 au while 12CO and C18O lines do not show. We investigate two possible mechanisms for reproducing the observed dust gap-ring structure and a gas temperature bump. First, the observed gap structure can be opened by a Jupiter mass planet using the relation between the planet mass and the gap depth and width. Meanwhile, the radiative transfer calculations based on the observed dust surface density profile show that the observed dust ring could be formed by dust accumulation at the gas temperature bump, that is, the gas pressure bump produced beyond the outer edge of the dust disk.
- [62] arXiv:1911.13049 [pdf, other]
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Title: (704) Interamnia: A transitional object between a dwarf planet and a typical irregular-shaped minor bodyAuthors: J. Hanuš, P. Vernazza, M. Viikinkoski, M. Ferrais, N. Rambaux, E. Podlewska-Gaca, A. Drouard, L. Jorda, E. Jehin, B. Carry, M. Marsset, F. Marchis, B. Warner, R. Behrend, V. Asenjo, N. Berger, M. Bronikowska, T. Brothers, S. Charbonnel, C. Colazo, J-F. Coliac, R. Duffard, A. Jones, A. Leroy, A. Marciniak, R. Melia, D. Molina, J. Nadolny, M. Person, O. Pejcha, H. Riemis, B. Shappee, K. Sobkowiak, F. Soldán, D. Suys, R. Szakats, J. Vantomme, M. Birlan, J. Berthier, P. Bartczak, C. Dumas, G. Dudziński, J. Ďurech, J. Castillo-Rogez, F. Cipriani, R. Fetick, T. Fusco, J.Grice, M. Kaasalainen, A. Kryszczynska, P. Lamy, T. Michalowski, P. Michel, T. Santana-Ros, P. Tanga, F. Vachier, A. Vigan, O. Witasse, B. YangComments: Accepter fr publication in Astronomy and AstrophysicsSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
With an estimated diameter in the 320 to 350 km range, (704) Interamnia is the fifth largest main belt asteroid and one of the few bodies that fills the gap in size between the four largest bodies with $D$ > 400 km (Ceres, Vesta, Pallas and Hygiea) and the numerous smaller bodies with $D$ $\lesssim$ 200 km. However, despite its large size, little is known about the shape and spin state of Interamnia and, therefore, about its bulk composition and past collisional evolution. We aimed to test at what size and mass the shape of a small body departs from a nearly ellipsoidal equilibrium shape (as observed in the case of the four largest asteroids) to an irregular shape as routinely observed in the case of smaller ($D$ $\lesssim$ 200 km) bodies. We observed Interamnia as part of our ESO VLT/SPHERE large program (ID: 199.C-0074) at thirteen different epochs. In addition, several new optical lightcurves were recorded. These data, along with stellar occultation data from the literature, were fed to the All-Data Asteroid Modeling (ADAM) algorithm to reconstruct the 3D-shape model of Interamnia and to determine its spin state. Interamnia's volume-equivalent diameter of 332 $\pm$ 6 km implies a bulk density of $\rho$=1.98 $\pm$ 0.68 gcm$^{-3}$ , which suggests that Interamnia - like Ceres and Hygiea - contains a high fraction of water ice, consistent with the paucity of apparent craters. Our observations reveal a shape that can be well approximated by an ellipsoid, and that is compatible with a fluid hydrostatic equilibrium at the 2 $\sigma$ level. The rather regular shape of Interamnia implies that the size and mass limit, under which the shapes of minor bodies with a high amount of water ice in the subsurface become irregular, has to be searched among smaller ($D$ $\lesssim$ 300km) less massive ($m$ $\lesssim$ 3x10$^{19}$ kg) bodies.
- [63] arXiv:1911.13058 [pdf, ps, other]
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Title: Searching for the magnetised Tidal Dwarf Galaxies in Hickson Compact Groups: HCG 26, 91, and 96Authors: Błażej Nikiel-WroczyńskiComments: 14 paqes (10 in the publisher's format), 6 figures, 4 tables. Published in the ApJJournal-ref: The Astrophysical Journal, Volume 885, Issue 2, article id. 107, 10 pp. (2019)Subjects: Astrophysics of Galaxies (astro-ph.GA)
In this work, archive 1.4 and 4.86 GHz radio continuum data from the VLA were re-reduced and, together with the 1.4 GHz maps from the NVSS, investigated for the presence of a detectable, non-thermal continuum radio emission that could be associated with the TDG candidates in HCG 26, 91, and 96. Radio emission highly coincident with the optical and $\rm H_{\alpha}$ emission maxima of the TDG candidate HCG 91i (estimated physical separation of less than 150 pc) was revealed. Should this emission be intrinsic to this object, it would imply the presence of a magnetic field as strong as 11--16 $\mu$G -- comparable to that found in the most radio-luminous, star-forming dwarf galaxies of non-tidal origin. However, the star formation rate derived for this object using the radio flux is about two orders of magnitude higher, than the one estimated from the $\rm H_{\alpha}$ data. Analysis of the auxiliary radio, ultraviolet and infrared data suggests that either the radio emission originates in a background object with an aged synchrotron spectrum (possibly a GHz-peaked source), or the $\rm SFR_{H_{\alpha}}$ estimate is lower due to the fact that it traces the most recent star formation, while most of the detected radio emission originated when what is known as HCG 91i was still a part of its parent galaxy. The latter scenario is supported by a very large stellar mass derived from 3.6 and 4.5 $\mu$m data, implying high star formation in the past.
- [64] arXiv:1911.13081 [pdf, other]
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Title: Kinematic and metallicity properties od the Aquarius dwarf galaxy from FORS2 MXU spectroscopyAuthors: L. Hermosa Muñoz, S. Taibi, G. Battaglia, G. Iorio, M. Rejkuba, R. Leaman, A. A. Cole, M. Irwin, P. Jablonka, N. Kacharov, A. McConnachie, E. Starkenburg, E. TolstoyComments: Accepted for publication in A&A. 15 pages, 9 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Dwarf galaxies found in isolation in the Local Group (LG) are unlikely to have interacted with the large LG spirals, and therefore environmental effects should not be the main drivers of their evolution. We aim to provide insight into the internal mechanisms shaping LG dwarf galaxies by increasing our knowledge of the internal properties of isolated systems. We focus on the evolved stellar component of the Aquarius dwarf, whose kinematic and metallicity properties have only recently started to be explored. We have obtained spectroscopic data in the the near-infrared CaII triplet lines region with FORS2 at the Very Large Telescope for 53 red giant branch (RGB) stars, to derive line-of-sight velocities and [Fe/H] of the individual RGB stars. We have derived a systemic velocity of $-142.2^{+1.8}_{-1.8}$ km s$^{-1}$, in agreement with previous measurements from both the HI gas and stars. The internal kinematics of Aquarius appears to be best modelled by a combination of random motions (l.o.s. velocity dispersion of $10.3^{+1.6}_{-1.3}$ km s$^{-1}$) and linear rotation (with a gradient $-5.0^{+1.6}_{-1.9}$ km s$^{-1}$ arcmin$^{-1}$) along a P.A.=$139_{-27}^{+17}$ deg, consistent with the optical projected major axis. This rotation signal is significantly misaligned or even counter-rotating to that derived from the HI gas. We also find the tentative presence of a mild negative metallicity gradient and indications that the metal-rich stars have a colder velocity dispersion than the metal-poor ones. This work represents a significant improvement with respect to previous measurements of the RGB stars of Aquarius, as it doubles the number of member stars studied in the literature. We speculate that the misaligned rotation between the HI gas and evolved stellar component might have been the result of recent accretion of HI gas or re-accretion after gas-loss due to internal stellar feedback.
- [65] arXiv:1911.13088 [pdf, other]
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Title: Calibration and 21-cm Power Spectrum Estimation in the Presence of Antenna Beam VariationsComments: 14 pages, 8 figures. Accepted for publication in MNRASSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Detecting a signal from the Epoch of Reionisation (EoR) requires an exquisite understanding of galactic and extra-galactic foregrounds, low frequency radio instruments, instrumental calibration, and data analysis pipelines. In this work we build upon existing work that aims to understand the impact of calibration errors on 21-cm power spectrum (PS) measurements. It is well established that calibration errors have the potential to inhibit EoR detections by introducing additional spectral features that mimic the structure of EoR signals. We present a straightforward way to estimate the impact of a wide variety of modelling residuals in EoR PS estimation. We apply this framework to the specific case of broken dipoles in Murchison Widefield Array (MWA) to understand its effect and estimate its impact on PS estimation. Combining an estimate of the percentage of MWA tiles that have at least one broken dipole (15\%-40\%) with an analytic description of beam errors induced by such dipoles, we compute the residuals of the foregrounds after calibration and source subtraction. We find that that incorrect beam modelling introduces bias in the 2D-PS on the order of $\sim 10^3\, \mathrm{mK}^2 \,h^{-3}\, \mathrm{Mpc}^{-3}$, which is on the order of current lowest limits. Determining the accuracy of both current beam models and direction dependent calibration pipelines is therefore crucial in our search for an EoR signal.
- [66] arXiv:1911.13090 [pdf, other]
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Title: Filaments and striations: anisotropies in observed, supersonic, highly-magnetised turbulent cloudsComments: 20 pages, 11 figures; accepted for publication in MNRAS, 2019, Nov. 29Subjects: Astrophysics of Galaxies (astro-ph.GA)
Stars form in highly-magnetised, supersonic turbulent molecular clouds. Many of the tools and models that we use to carry out star formation studies rely upon the assumption of cloud isotropy. However, structures like high-density filaments in the presence of magnetic fields, and magnetosonic striations introduce anisotropies into the cloud. In this study we use the two-dimensional (2D) power spectrum to perform a systematic analysis of the anisotropies in the column density for a range of Alfv\'en Mach numbers ($\mathcal{M}_A=0.1$--$10$) and turbulent Mach numbers ($\mathcal{M}=2$--$20$), with 20 high-resolution, three-dimensional (3D) turbulent magnetohydrodynamic simulations. We find that for cases with a strong magnetic guide field, corresponding to $\mathcal{M}_A<1$, and $\mathcal{M}\lesssim 4$, the anisotropy in the column density is dominated by thin striations aligned with the magnetic field, while for $\mathcal{M}\gtrsim 4$ the anisotropy is significantly changed by high-density filaments that form perpendicular to the magnetic guide field. Indeed, the strength of the magnetic field controls the degree of anisotropy and whether or not any anisotropy is present, but it is the turbulent motions controlled by $\mathcal{M}$ that determine which kind of anisotropy dominates the morphology of a cloud.
- [67] arXiv:1911.13093 [pdf, other]
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Title: The Lagrangian hydrodynamics code MAGMA2Authors: Stephan RosswogComments: 22 pages, 23 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE); Computational Physics (physics.comp-ph)
We present the methodology and performance of the new Lagrangian hydrodynamics code MAGMA2, a Smoothed Particle Hydrodynamics code that benefits from a number of non-standard enhancements. It uses high-order smoothing kernels and wherever gradients are needed, they are calculated via accurate matrix inversion techniques. Our default version does not make use of any kernel gradients, but a more conventional formulation has also been implemented for comparison purposes. MAGMA2 uses artificial viscosity, but enhanced by techniques that are commonly used in finite volume schemes such as reconstruction and slope limiting. While simple to implement, this approach efficiently suppresses particle noise, but at the same time drastically reduces dissipation in locations where it is not needed and actually unwanted. We demonstrate the performance of the new code in a number of challenging benchmark tests including e.g. complex, multi-dimensional Riemann problems and more astrophysical tests such as a collision between two stars to demonstrate its robustness and excellent conservation properties.
- [68] arXiv:1911.13094 [pdf, ps, other]
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Title: Cycle times of early M dwarf stars: mean field models versus observationsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Observations of early-type M stars suggest that there are two characteristic cycle times, one of order one year for fast rotators ($P_{\rm rot} < 1$ day) and another of order four years for slower rotators. For a sample of fast-rotating stars, the equator-to-pole differences of the rotation rates up to 0.03 rad d$^{-1}$ are also known from Kepler data. These findings are well-reproduced by mean field models. These models predict amplitudes of the meridional flow, from which the travel time from pole to equator at the base of the convection zone of early-type M stars can be calculated. As these travel times always exceed the observed cycle times, our findings do not support the flux transport dynamo.
- [69] arXiv:1911.13102 [pdf, ps, other]
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Title: The period-luminosity relation for Cepheids derived from multiphase temperature measurements and Cepheids kinematics based on GAIA DR2 dataComments: 8 pages, 6 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Calibration of the period-luminosity relation (PLR) for Cepheids has always been one of the biggest goals of stellar astronomy. Among a considerable number of different approaches, the Baade-Becker-Wesselink (BBW) method stands in the foreground as one of the most universal and precise methods. We present a new realization of the BBW method which is considered to be the generalization of surface brightness (\citealt{Barnes+Evans+1976}) and \cite{Balona+1977} approaches first proposed by \cite{Rastorguev+Dambis+2010} and described in \cite{Paper1}. One of the main features of this method is using measured effective temperature variations to determine the main parameters of Cepheid, such as distance, radius, luminosity, colour excess, intrinsic colour. We apply this method to 45 Cepheids of Northern sky, for which multiphase temperature data are available. We take into account the effect of shock waves, whose presence in stellar atmosphere distorts the observational data and the calibrations used in this work. Within $0.0-0.87$ phase interval we derived PL relation $<M_V>_I=-(2.67 \pm 0.17)\cdot logP - (1.58 \pm 0.16)$. It was used to calculate the distances, rotation curve and kinematical parameters of the sample of 435 Cepheids with GAIA DR2 proper motions.
- [70] arXiv:1911.13107 [pdf, ps, other]
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Title: Investigation of X-ray timing and spectral properties of ESO 243-49 HLX-1 with long-term Swift MonitoringAuthors: Lupin Chun-Che Lin, Chin-Ping Hu, Kwan-Lok Li, Jumpei Takata, David Chien-Chang Yen, Kyujin Kwak, Young-Min Kim, Albert K. H. KongComments: 12 pages, 4 tables and 7 figures; accepted by MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The long-term Swift monitoring of ESO 243-49 HLX-1 provides an opportunity to investigate the detailed timing and spectral behaviour of this hyper-luminous X-ray source. Swift has detected 7 outbursts since 2009 mid-August. Using different dynamical timing algorithms, we confirm an increasing trend for the time intervals between outbursts, which is manifest in the delays between the latest outbursts. The X-ray spectra of HLX-1 in quiescence can be described with a single power-law model while the thermal component dominates the X-ray emission during outburst. There is only marginal evidence for photon index (or spectral hardness) changes between quiescent states with about 1{\sigma} deviation. With the updated temporal and spectral features, we re-examine different scenarios to explain the origin of the quasi-periodic modulation of HLX-1. A significantly increasing trend without obvious stochastic fluctuations on the timescale of the detected quasi-period may not fully support an orbital period origin as might be due to mass transfer episodes from a donor star at periastron of an extremely eccentric orbit. The outburst profile seems to be consistent with the effect of tidal-induced-precession of an accretion disc or an oscillating wind scenario in the inner disc. Based on these models, we speculate that the true orbital period is much shorter than the detected quasi-periodicity.
- [71] arXiv:1911.13108 [pdf, other]
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Title: Measuring bulk flows of the intracluster medium in the Perseus and Coma galaxy clusters using XMM-NewtonAuthors: J. S. Sanders, K. Dennerl, H. R. Russell, D. Eckert, C. Pinto, A. C. Fabian, S. A. Walker, T. Tamura, J. ZuHone, F. HofmannComments: 33 pages, 28 figures, accepted by A&ASubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
We demonstrate a novel technique for calibrating the energy scale of the XMM EPIC-pn detector, which allows us to measure bulk flows in the intracluster medium (ICM) of the Perseus and Coma clusters. The procedure uses the instrumental lines present in all observations, in particular, Cu-Ka. By studying their spatial and temporal variations, in addition to incorporating calibration observations, we refined the absolute energy scale to better than 150 km/s at the Fe-K line, a large improvement over the nominal accuracy of 550 km/s. We then mapped the bulk motions over much of the central 1200 and 800 kpc of Perseus and Coma, respectively, in spatial regions down to 65 and 140 kpc size. We cross-checked our procedure by comparing our measurements with those found in Perseus by Hitomi for an overlapping region, finding consistent results. For Perseus, there is a LoS velocity increase of 480+-210 km/s (1sigma) 250 kpc east of the nucleus. This region is associated with a cold front, providing direct evidence of the ICM sloshing in the potential well. Assuming the intrinsic distribution of bulk motions is Gaussian, its width is 214+-85 km/s, excluding systematics. Removing the sloshing region, this is reduced to 20-150 km/s, which is similar in magnitude to the Hitomi line width measurements in undisturbed regions. In Coma, the line-of-sight velocity of the ICM varies between the velocities of the two central galaxies. Maps of the gas velocity and metallicity provide clues about the merger history of the Coma, with material to the north and east of the cluster core having a velocity similar to NGC 4874, while that to the south and west has velocities close to NGC 4889. Our results highlight the difference between a merging system, such as Coma, where we observe a ~1000 km/s range in velocity, and a relatively relaxed system, such as Perseus, with much weaker bulk motions. [abridged]
- [72] arXiv:1911.13113 [pdf, ps, other]
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Title: Photometric rotation periods for 107 M dwarfs from the APACHE surveyAuthors: P. Giacobbe, M. Benedetto, M. Damasso, A. Sozzetti, J.M. Christille, M.G. Lattanzi, P. Calcidese, A. Carbognani, D. Barbato, M. Pinamonti, E. Poggio, A. F. Lanza, A. Bernagozzi, D. Cenadelli, L. Lanteri, E. BertoliniSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present rotation period measurements for 107 M dwarfs in the mass range $0.15-0.70 M_\odot$ observed within the context of the APACHE photometric survey. We measure rotation periods in the range 0.5-190 days, with the distribution peaking at $\sim$ 30 days. We revise the stellar masses and radii for our sample of rotators by exploiting the Gaia DR2 data. For $\sim 20\%$ of the sample, we compare the photometric rotation periods with those derived from different spectroscopic indicators, finding good correspondence in most cases. We compare our rotation periods distribution to the one obtained by the Kepler survey in the same mass range, and to that derived by the MEarth survey for stars in the mass range $0.07-0.25 M_\odot$. The APACHE and Kepler periods distributions are in good agreement, confirming the reliability of our results, while the APACHE distribution is consistent with the MEarth result only for the older/slow rotators, and in the overlapping mass range of the two surveys. Combining the APACHE/Kepler distribution with the MEarth distribution, we highlight that the rotation period increases with decreasing stellar mass, in agreement with previous work. Our findings also suggest that the spin-down time scale, from fast to slow rotators, changes crossing the fully convective limit at $\approx0.3 M_\odot$ for M dwarfs. The catalogue of 107 rotating M dwarfs presented here is particularly timely, as the stars are prime targets for the potential identification of transiting small planets with TESS and amenable to high-precision mass determination and further atmospheric characterization measurements.
- [73] arXiv:1911.13128 [pdf, ps, other]
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Title: The effects of unresolved double-degenerates in the white dwarf luminosity functionComments: accepted for publication by MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We perform an analysis of the single white dwarf and the double degenerate binary populations in the solar neighbourhood following a population synthesis approach to investigate the effects of unresolved double degenerates in the white dwarf luminosity function. We consider all unresolved synthetic binaries to be associated with fictitious effective temperatures and surface gravities that are obtained in the same way as if these objects were observed as single point sources. We evaluate the effects of unresolved double white dwarfs assuming that the synthetic samples are observed both by the magnitude-limited SDSS and the volume-limited Gaia surveys, the latter limited to a distance of no more than 100pc. We find that, for our standard model, the impact of unresolved double degenerates in the white dwarf luminosity function derived from the Gaia sample is nearly negligible. Unresolved double degenerates are hence expected to have no effect on the age of the Galactic disc, nor on the star formation history from this population. However, for the SDSS sample, the effect of unresolved double degenerates is significant at the brighter bins (Mbol<6.5 mag), with the fraction of such systems reaching ~40% of the total white dwarf population at Mbol=6 mag. This indicates unresolved double degenerates may influence the constraints on the star formation history derived from the SDSS white dwarf sample.
- [74] arXiv:1911.13132 [pdf, ps, other]
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Title: The Gaia-ESO Survey: Carbon abundance in the Galactic thin and thick disksAuthors: Mariagrazia Franchini, Carlo Morossi, Paolo Di Marcantonio, Miguel Chavez, Vardan Zh. Adibekyan, Amelia Bayo, Thomas Bensby, Angela Bragaglia, Francesco Calura, Sonia Duffau, Anais Gonneau, Ulrike Heiter, Georges Kordopatis, Donatella Romano, Luca Sbordone, Rodolfo Smiljanic, Grazina Tautvaisiene, Mathieu Van der Swaelmen, Elisa Delgado Mena, Gerry Gilmore, Sofia Randich, Giovanni Carraro, Anna Hourihane, Laura Magrini, Lorenzo Morbidelli, Sergio Sousa, C. Clare WorleyComments: 27 pages, 15 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
This paper focuses on carbon that is one of the most abundant elements in the Universe and is of high importance in the field of nucleosynthesis and galactic and stellar evolution. Even nowadays, the origin of carbon and the relative importance of massive and low- to intermediate-mass stars in producing it is still a matter of debate. In this paper we aim at better understanding the origin of carbon by studying the trends of [C/H], [C/Fe],and [C/Mg] versus [Fe/H], and [Mg/H] for 2133 FGK dwarf stars from the fifth Gaia-ESO Survey internal data release (GES iDR5). The availability of accurate parallaxes and proper motions from Gaia DR2 and radial velocities from GES iDR5 allows us to compute Galactic velocities, orbits and absolute magnitudes and, for 1751 stars, ages via a Bayesian approach. Three different selection methodologies have been adopted to discriminate between thin and thick disk stars. In all the cases, the two stellar groups show different abundance ratios, [C/H], [C/Fe], and [C/Mg], and span different age intervals, with the thick disk stars being, on average, older than those in the thin disk. The behaviours of [C/H], [C/Fe], and [C/Mg] versus [Fe/H], [Mg/H], and age all suggest that C is primarily produced in massive stars like Mg. The increase of [C/Mg] for young thin disk stars indicates a contribution from low-mass stars or the increased C production from massive stars at high metallicities due to the enhanced mass loss. The analysis of the orbital parameters Rmed and |Zmax| support an "inside-out" and "upside-down" formation scenario for the disks of Milky Way.
- [75] arXiv:1911.13148 [pdf, other]
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Title: The KISS experimentAuthors: A. Fasano, M. Aguiar, A. Benoit, A. Bideaud, O. Bourrion, M. Calvo, A. Catalano, A. P. de Taoro, G. Garde, A. Gomez, M. F. Gomez Renasco, J. Goupy, C. Hoarau, R. Hoyland, J. F. Macías-Pérez, J. Marpaud, A. Monfardini, G. Pisano, N. Ponthieu, J. A. Rubiño Martín, D. Tourres, C. Tucker, A. Beelen, G. Bres, M. De Petris, P. de Bernardis, G. Lagache, L. Lamagna, G. Luzzi, M. Marton, S. Masi, R. Rebolo, S. RoudierComments: 7 pages, 6 figures, Accepted for publication in Journal of Low Temperature PhysicsSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Mapping millimetre continuum emission has become a key issue in modern multi-wavelength astrophysics. In particular, spectrum-imaging at low frequency resolution is an asset for characterizing the clusters of galaxies via the Sunyaev Zeldovich (SZ) effect. In this context, we have built a ground-based spectrum-imager named KIDs Interferometer Spectrum Survey (KISS). This instrument is based on two 316-pixel arrays of Kinetic Inductance Detectors (KID) cooled to 150 mK by a custom dilution refrigerator-based cryostat. By using Ti-Al and Al absorbers, we can cover a wide frequency range between 80 and 300 GHz. In order to preserve a large instantaneous Field of View (FoV) 1 degree the spectrometer is based on a Fourier Transform interferometer. This represents a technological challenge due to the fast scanning speed that is needed to overcome the effects of background atmospheric fluctuations. KISS is installed at the QUIJOTE 2.25 m telescope in Tenerife since February 2019 and is currently in its commissioning phase. In this proceeding we present an overview of the instrument and the latest results.
- [76] arXiv:1911.13153 [pdf, other]
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Title: Geometrical and physical optics analysis for mm-wavelength refractor telescopes designed to map the cosmic microwave backgroundAuthors: Jon E. GudmundssonComments: 15 pages, 17 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Optics (physics.optics)
We present a compact two-lens HDPE f/1.6 refractor design that is capable of supporting a 28-deg diffraction-limited field of view at 1-mm wavelengths and contrast it to a similar two-lens refractor using silicon lenses. We compare the optical properties of these two systems as predicted by both geometrical and physical optics. The presented analysis suggests that by relaxing telecentricity requirements, a plastic two-lens refractor system can perform comparably to a similar silicon system across a wide field of view and wavelengths up to 1 mm. We show that for both telescope designs, cold stop spillover changes significantly across the field of view in a way that is somewhat inconsistent with Gaussian beam formalism and simple f-number scaling. We present results that highlight beam ellipticity dependence on both pixel location and pixel aperture size --- an effect that is challenging to reproduce in standard geometrical optics. We show that a silicon refractor design suffers from larger cross-polarization compared to the HDPE design. Our results address the limitations of solely relying on geometrical optics to assess relative performance of two optical systems. We discuss implications for future refractor designs.
- [77] arXiv:1911.13158 [pdf, other]
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Title: THOR 2.0: Major Improvements to the Open-Source General Circulation ModelAuthors: Russell Deitrick, João M. Mendonça, Urs Schroffenegger, Simon L. Grimm, Shang-Min Tsai, Kevin HengComments: 52 pages, 30 figures, submitted to AAS JournalsSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
THOR is the first open-source general circulation model (GCM) developed from scratch to study the atmospheres and climates of exoplanets, free from Earth- or Solar System-centric tunings. It solves the general non-hydrostatic Euler equations (instead of the primitive equations) on a sphere using the icosahedral grid. In the current study, we report major upgrades to THOR, building upon the work of Mendon\c{c}a et al. (2016). First, while the Horizontally Explicit Vertically Implicit (HEVI) integration scheme is the same as that described in Mendon\c{c}a et al. (2016), we provide a clearer description of the scheme and improved its implementation in the code. The differences in implementation between the hydrostatic shallow (HSS), quasi-hydrostatic deep (QHD) and non-hydrostatic deep (NHD) treatments are fully detailed. Second, key code improvements are reported including the elimination of atomic addition and its replacement by reduction addition, as well as ensuring binary reproducibility. Third, standard physics modules are added: two-stream, double-gray radiative transfer and dry convective adjustment. Fourth, THOR is tested on additional benchmarks: tidally-locked Earth, deep hot Jupiter, acoustic wave, and gravity wave. Fifth, we report that differences between the hydrostatic and non-hydrostatic simulations are negligible in the Earth case, but pronounced in the hot Jupiter case. Finally, the effects of the so-called "sponge layer", a form of drag implemented in most GCMs to provide numerical stability, are examined. Overall, these upgrades have improved the flexibility, user-friendliness, and stability of THOR.
- [78] arXiv:1911.13188 [pdf, other]
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Title: Baryon acoustic oscillations from Integrated Neutral Gas Observations: Broadband corrugated horn construction and testingAuthors: C.A. Wuensche, L. Reitano, M.W. Peel, I.W.A. Browne, B. Maffei, E. Abdalla, C. Radcliffe, F. Abdalla, L. Barosi, V. Liccardo, E. Mericia, G. Pisano, C. Strauss, F. Vieira, T. Villela, B. WangComments: Submitted for publication in Experimental AstronomySubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The Baryon acoustic oscillations from Integrated Neutral Gas Observations (BINGO) telescope is a 40-m~class radio telescope under construction that has been designed to measure the large-angular-scale intensity of HI emission at 980--1260 MHz and hence to constrain dark energy parameters. A large focal plane array comprising of 1.7-metre diameter, 4.3-metre length corrugated feed horns is required in order to optimally illuminate the telescope. Additionally, very clean beams with low sidelobes across a broad frequency range are required, in order to facilitate the separation of the faint HI emission from bright Galactic foreground emission. Using novel construction methods, a full-sized prototype horn has been assembled. It has an average insertion loss of around 0.15 dB across the band, with a return loss around -25 dB. The main beam is Gaussian with the first sidelobe at around $-25 dB. A septum polariser to separate the signal into the two hands of circular polarization has also been designed, built and tested.
- [79] arXiv:1911.13267 [pdf, other]
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Title: Common Origin of Warm Dark Matter and Dark RadiationComments: 20 pages, 2 appendices, and referencesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
We consider a cosmological scenario where a relativistic particle and a stable massive particle are simultaneously produced from the decay of a late-decaying particle after Big-Bang Nucleosynthesis but before matter-radiation equality. The relativistic and massive particles behave as dark radiation and warm dark matter, respectively. Due to a common origin, the warmness and abundances are closely related. We refer to the models that lead to such a scenario as Common Origin of Warm and Relativistic Decay Products (COWaRD). We show that COWaRD predicts a correlation between the amount of dark radiation and suppression of the large scale structure, which can be tested in future precision cosmology observations. We demonstrate that COWaRD is realized, as an example, in a class of supersymmetric axion models and that future observations by the next generation Cosmic Microwave Background, Large Scalar Structure, and 21-cm surveys can reveal the structure of the theory.
- [80] arXiv:1911.13281 [pdf, other]
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Title: Compact Dark Matter Objects via $N$ Dark SectorsComments: 13 pages, 2 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
We propose a novel class of compact dark matter objects in theories where the dark matter consists of multiple sectors. We call these objects $N$-MACHOs. In such theories neither the existence of dark matter species nor their extremely weak coupling to the observable sector represent additional hypotheses but instead are imposed by the solution to the Hierarchy Problem and unitarity. The crucial point is that particles from the same sector have non-trivial interactions but interact only gravitationally otherwise. As a consequence, the pressure that counteracts the gravitational collapse is reduced while the gravitational force remains the same. This results in collapsed structures much lighter and smaller as compared to the ordinary single-sector case. We apply this phenomenon to a dark matter theory that consists of $N$ dilute copies of the Standard Model. The solutions do not rely on an exotic stabilization mechanism, but rather use the same well-understood properties as known stellar structures. This framework also gives rise to new microscopic superheavy structures, for example with mass $10^8$\,g and size $10^{-13}$\,cm. By confronting the resulting objects with observational constraints, we find that, due to a huge suppression factor entering the mass spectrum, these objects evade the strongest constrained region of the parameter space. Finally, we discuss possible formation scenarios of $N$-MACHOs. We argue that, due to the efficient dissipation of energy on small scales, high-density regions such as ultra-compact mini-halos could serve as formation sites of $N$-MACHOs.
- [81] arXiv:1911.13285 [pdf, other]
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Title: Dipolar stability in spherical simulations: the impact of an inner stable zoneComments: 4 pages, 5 figs, IAU 354, proceedingsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Fluid Dynamics (physics.flu-dyn)
Magnetic fields vary in complexity for different stars. The stability of dipolar magnetic fields is known to depend on different quantities, e.g., the stellar rotation, the stratification, and the intensity of convective motions. Here, we study the dipolar stability in a system with an inner stable zone. We present preliminary results of dynamo simulations using the Rayleigh number as a control parameter. The stiffness of the stable zone is accordingly varied to keep a constant ratio of the Brunt-Vaisala frequency to the angular velocity. Similarly to the completely convective spherical shell, we find that a transition exists between a regime where the magnetic field is dipolar to a multipolar regime when the Rossby number is increased. The value of the Rossby number at the transition is very close to the one of the fully convective case.
- [82] arXiv:1911.13296 [pdf, other]
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Title: The SOPHIE search for northern extrasolar planets. XVII. A compact planetary system in a near 3:2 mean motion resonance chainAuthors: N. C. Hara, F. Bouchy, M. Stalport, I. Boisse, J. Rodrigues, J-. B. Delisle, A. Santerne, G. W. Henry, L. Arnold, N. Astudillo-Defru, S. Borgniet, X.Bonfils, V. Bourrier, B. Brugger, B. Courcol, S. Dalal, M. Deleuil, X. Delfosse, O. Demangeon, R. F. D'iaz, X. Dumusque, T. Forveille, G. Hébrard, M. Hobson, F. Kiefer, T. Lopez, L. Mignon, O. Mousis, C. Moutou, F. Pepe, J. Rey, N. C. Santos, D. Ségransan, S. Udry, P. A. WilsonComments: Submitted to A&ASubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Since 2011, the SOPHIE spectrograph has been used to search for Neptunes and Super-Earths in the northern hemisphere. As part of this observation program, 290 radial velocity measurements of HD 158259 were obtained. We present the analysis of this dataset. The radial velocity data, corrected from instrument systematics, are analysed with classical and $\ell_1$ periodograms. The stellar activity is modelled by a correlated Gaussian noise, and its impact on the planets detection is measured by a new technique based on cross-validation. Ancillary spectroscopic indices as well as photometric measurements are analysed to discuss the planetary origin of the signals. The stability of the system is assessed with numerical simulations. We report the detection of four planets in a chain of near 3:2 mean motion resonances around HD 158259 at 3.4, 5.2, 7.9 and 12 days, with a possible fifth planet at 17.4 days, also near the 3:2 resonance. Additionally, two low frequency signals are found in the data, and are attributed to a magnetic cycle and instrument systematics. The four planets are found to be outside of the two and three body resonances.
Cross-lists for Mon, 2 Dec 19
- [83] arXiv:1910.02615 (cross-list from physics.space-ph) [pdf]
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Title: Effects of CME and CIR induced geomagnetic storms on low-latitude ionization over Indian longitudes in terms of neutral dynamicsComments: 41 pages, 14 figures. Accepted for publication in Advances in Space ResearchSubjects: Space Physics (physics.space-ph); Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
This paper presents the response of the ionosphere during the intense geomagnetic storms of October 12-20, 2016 and May 26-31, 2017 which occurred during the declining phase of the solar cycle 24. Total Electron Content (TEC) from GPS measured at Indore, Calcutta and Siliguri having geomagnetic dips varying from 32.23{\deg}N, 32{\deg}N and 39.49{\deg}N respectively and at the International GNSS Service (IGS) stations at Lucknow (beyond anomaly crest), Hyderabad (between geomagnetic equator and northern crest of EIA) and Bangalore (near magnetic equator) in the Indian longitude zone have been used for the storms. Prominent peaks in diurnal maximum in excess of 20-45 TECU over the quiet time values were observed during the October 2016 storm at Lucknow, Indore, Hyderabad, Bangalore and 10-20 TECU for the May 2017 storm at Siliguri, Indore, Calcutta and Hyderabad. The GUVI images onboard TIMED spacecraft that measures the thermospheric O/N2 ratio, showed high values (O/N2 ratio of about 0.7) on October 16 when positive storm effects were observed compared to the other days during the storm period. The observed features have been explained in terms of the O/N2 ratio increase in the equatorial thermosphere, CIR-induced High Speed Solar Wind (HSSW) event for the October 2016 storm. The TEC enhancement has also been explained in terms of the Auroral Electrojet (AE), neutral wind values obtained from the Horizontal Wind Model (HWM14) and equatorial electrojet strength from magnetometer data for both October 2016 and May 2017 storms. These results are one of the first to be reported from the Indian longitude sector on influence of CME- and CIR-driven geomagnetic storms on TEC during the declining phase of solar cycle 24.
- [84] arXiv:1911.07695 (cross-list from gr-qc) [pdf, ps, other]
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Title: Silhouettes of invisible black holesComments: 21 pages, 23 figure, review paper submitted to Physics UspekhiSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
Review of the genuine black holes silhouettes. The isolated black holes are the invisible objects in general relativity due to their physical properties. Nevertheless, the dark silhouette of the astrophysical black hole may be visible by a distant observer in the result of luminous matter lensing in the gravitational field of the black hole. Depending on astrophysical conditions, it is possible to see either the black hole shadow or the event horizon silhouette itself. In the case of a stationary luminous background (placed beyond the photon sphere), it is seen the black hole shadow, which is a projection on the celestial sphere of the photon capture cross-section in the black hole gravitational field. Meanwhile, in the case of nonstationary emitting matter in the inner part of the thin accretion disk, adjoining the event horizon, it would be seen the dark silhouette of the event horizon. Just the dark silhouette of the event horizon is seen on the first image of the supermassive black hole M87* obtained by Event Horizon Telescope. The brightness of accretion matter near the black hole highly exceeds the corresponding one of the usual astrophysical stationary background in the form of stars or gas clouds. For this reason, it is improbable to observe the black hole shadow in the presence of a very luminous accretion matter.
- [85] arXiv:1911.12365 (cross-list from hep-ph) [pdf, other]
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Title: The Inconsistency of Superfluid Dark Matter with Milky Way DynamicsComments: 6+5 pages, 2+4 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
There are many well-known correlations between dark matter and baryons that exist on galactic scales. These correlations can essentially be encompassed by a simple scaling relation between observed and baryonic accelerations, historically known as the Mass Discrepancy Acceleration Relation (MDAR). The existence of such a relation has prompted many theories that attempt to explain the correlations by invoking additional fundamental forces on baryons. The standard lore has been that a theory that reduces to the MDAR on galaxy scales but behaves like cold dark matter (CDM) on larger scales provides an excellent fit to data, since CDM is desirable on scales of clusters and above. However, this statement should be revised in light of recent results showing that a fundamental force that reproduces the MDAR is challenged by Milky Way dynamics. In this study, we test this claim on the example of Superfluid Dark Matter. We find that a standard CDM model is strongly preferred over a static superfluid profile. This is due to the fact that the superfluid model over-predicts vertical accelerations, even while reproducing galactic rotation curves. Our results establish an important criterion that any dark matter model must satisfy within the Milky Way.
- [86] arXiv:1911.12374 (cross-list from gr-qc) [pdf, other]
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Title: Cosmological direct detection of dark energyComments: 14 pages, 7 figures, comments are welcomeSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We consider the possibility that dark energy and baryons might scatter off each other. The type of interaction we consider leads to a pure momentum exchange, and does not affect the background evolution of the expansion history. We parametrize this interaction in an effective way at the level of Boltzmann equations. We compute the effect of dark energy-baryon scattering on cosmological observables, focusing on the Cosmic Microwave Background (CMB) temperature anisotropy power spectrum and the matter power spectrum. Surprisingly, we find that even huge dark energy-baryon cross-sections $\sigma_{xb} \sim {\cal O}({\rm b})$, which are generically excluded by non-cosmological probes such as collider searches or precision gravity tests, only leave an insignificant imprint on the observables considered. In the case of the CMB temperature power spectrum, the only imprint consists in a sub-percent enhancement or depletion of power (depending whether or not the dark energy equation of state lies above or below $-1$) at very low multipoles, which is thus swamped by cosmic variance. These effects are explained in terms of differences in how gravitational potentials decay in the presence of a dark energy-baryon scattering, which ultimately lead to an increase or decrease in the late-time integrated Sachs-Wolfe power. Even smaller related effects are imprinted on the matter power spectrum. The imprints on the CMB are not expected to be degenerate with the effects due to altering the dark energy sound speed. We conclude that, while strongly appealing, the prospects for a direct detection of dark energy through cosmology do not seem feasible when considering realistic dark energy-baryon cross-sections.
- [87] arXiv:1911.12601 (cross-list from hep-ph) [pdf, ps, other]
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Title: Is a WIMP explanation of the DAMA modulation effect still viable?Comments: 4 pages, 1 figure, contribution to the proceedings of the 16th TAUP conference, Sept. 9-13 2019, Toyama, JapanSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We show that the weakly interacting massive particle (WIMP) scenario of proton-philic spin-dependent inelastic dark matter can still provide a viable explanation of the observed DAMA effect in compliance with the constraints from other experiments. We also show that, although the COSINE-100 collaboration has recently tested the DAMA effect using the same target material, for the time being the comparison between DAMA and COSINE-100 still depends on the particle-physics model.
- [88] arXiv:1911.12805 (cross-list from hep-ph) [pdf, other]
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Title: Analysis of programming tools in framework of dark matter physics and concept of new MC-generatorComments: to appear in Proceedings of the XXII International Workshop What comes beyond the Standard Models,06-14 July 2019, Bled, SloveniaSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
We analyse here some programming tools (MC-generators) from viewpoint of their application to the tasks of dark matter (DM) interpretation of cosmic rays puzzles. We shortly describe our tasks, where the main goal is the solution of the problem of suppression of gamma-rays induced by the products of DM decay or annihilation in Galaxy. We show that existing MC-generators do not fully satisfy our task, comparing them, and suggest our own one.
- [89] arXiv:1911.12808 (cross-list from physics.atom-ph) [pdf, other]
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Title: Precision frequency-comb terahertz spectroscopy on pure quantum states of a single molecular ionAuthors: Chin-wen Chou, Alejandra L. Collopy, Christoph Kurz, Yiheng Lin, Michael E. Harding, Philipp N. Plessow, Tara Fortier, Scott Diddams, Dietrich Leibfried, David. R. LeibrandtComments: 25 pages, 4 figures, 6 tablesSubjects: Atomic Physics (physics.atom-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM); Quantum Physics (quant-ph)
Spectroscopy is a powerful tool for studying molecules and is commonly performed on large thermal molecular ensembles that are perturbed by motional shifts and interactions with the environment and one another, resulting in convoluted spectra and limited resolution. Here, we use generally applicable quantum-logic techniques to prepare a trapped molecular ion in a single quantum state, drive terahertz rotational transitions with an optical frequency comb, and read out the final state non-destructively, leaving the molecule ready for further manipulation. We resolve rotational transitions to 11 significant digits and derive the rotational constant of CaH+ to be B_R = 142501777.9(1.7) kHz. Our approach suits a wide range of molecular ions, including polyatomics and species relevant for tests of fundamental physics, chemistry, and astrophysics.
- [90] arXiv:1911.13291 (cross-list from hep-ph) [pdf, other]
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Title: Search for decaying eV-mass axion-like particles using gamma-ray signal from blazarsSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
Decaying axion-like particles (ALP) with masses in the eV range which might occupy dark matter halos of the Milky Way and other galaxies produce a characteristic "bump" feature in the spectrum of extragalactic background light (EBL). This feature leaves an imprint on the gamma-ray spectra of distant extragalactic sources. We derive constraints on the ALP coupling to photons based on analysis of spectra of very-high-energy gamma-ray loud blazars. We combine gamma-ray spectral measurements by Fermi/LAT and Cherenkov telescopes and fit a model in which the intrinsic source spectrum is modified by pair production on photons produced by ALP decays. We constrain the amplitude of gamma-ray flux suppression by this effect. We find that the combined Fermi/LAT and VERITAS data set for the source 1ES 1218+304 currently provides the tightest constraint on ALP-two-photon coupling which is complementary to the constraints imposed by non-observation of excess energy loss in Horizontal Branch stars, by the high-resolution spectroscopic observations of galaxy clusters with optical telescopes and by the searches of ALP signal with CERN Solar Axion Telescope. Our analysis favours existence of a bump in the EBL spectrum which could be produced by ALPs in the mass range 2-3 eV and axion-photon coupling $\sim 10^{-10}$ GeV$^{-1}$. We discuss possibilities for verification of this hint with deeper Cherenkov telescope observations of large number of blazars with current generation instruments and with the Cherenkov Telescope Array.
- [91] arXiv:1911.13293 (cross-list from hep-ph) [pdf, other]
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Title: Relativistic capture of dark matter by electrons in neutron starsComments: 6 pages, 1 figureSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
Dark matter can capture in neutron stars and heat them to observable luminosities. We study relativistic scattering of dark matter on highly degenerate electrons. We develop a Lorentz invariant formalism to calculate the capture probability of dark matter that accounts for the relativistic motion of the target particles and Pauli exclusion principle. We find that the actual capture probability can be five orders of magnitude larger than the one estimated using a nonrelativistic approach. For dark matter masses $10~{\rm eV}\textup{--}10~{\rm PeV}$, neutron star heating complements and can be more sensitive than terrestrial direct detection searches. Our results show that old neutron stars could be the most promising target for discovering leptophilic dark matter.
Replacements for Mon, 2 Dec 19
- [92] arXiv:1707.02906 (replaced) [pdf, ps, other]
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Title: The effect of close-in giant planets' evolution on tidal-induced migration of exomoonsComments: Published in Monthly Notices of the Royal Astronomical Society. 9 pages, 9 figuresJournal-ref: Monthly Notices of the Royal Astronomical Society, Volume 471, Issue 3, July 2017, Pages 3019-3027Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [93] arXiv:1708.04600 (replaced) [pdf, other]
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Title: Anomalous light curves of young tilted exoringsComments: Published in MNRAS Letters-RV2. 5 pages, 4 figuresJournal-ref: Monthly Notices of the Royal Astronomical Society: Letters, Volume 472, Issue 1, 21 November 2017, Pages L120-L124Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [94] arXiv:1810.05301 (replaced) [pdf, other]
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Title: Arbitrarily coupled $p-$forms in cosmological backgroundsComments: Several modifications and updates. The discussion about the $3-$forms is reviewed and corrected. A new application included. Several references added. Main conclusions unchangedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
- [95] arXiv:1811.07363 (replaced) [pdf, other]
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Title: On the zero point energy of composite particles: the medium effectsAuthors: Toru KojoComments: v2) 32 pages, 13 figures; discussions expanded and loopholes in the previous versions were correctedSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th); Nuclear Theory (nucl-th)
- [96] arXiv:1902.03014 (replaced) [pdf, other]
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Title: Some Aspects of the Canonical Analysis of Reuter-Weyer RG Improved Einstein-Hilbert ActionAuthors: Gabriele Gionti, S.JComments: revised version, corrected typos and the formula of the Poisson bracket between Hamiltonian-Hamiltonian constraints, 11 pages, 1 figure, proceedings of the conference "DICE2018" 17-21 September 2018, Castiglioncello (LI)Journal-ref: J. Phys.: Conf. Ser. 1275 012048 (2019)Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
- [97] arXiv:1903.06179 (replaced) [pdf, other]
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Title: Cosmic Reionization On Computers: Reionization Histories of Present-day GalaxiesComments: 7 pages, 5 figures, Accepted to ApJSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
- [98] arXiv:1904.01454 (replaced) [pdf, other]
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Title: Hard and bright gamma-ray emission at the base of the Fermi bubblesComments: 24 pages, 18 figures, published in A&AJournal-ref: A&A 625, A110 (2019)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [99] arXiv:1905.08206 (replaced) [src]
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Title: Fuzzy operators and the quantized electromagnetic field in the very-high-energy regimeAuthors: Fernando ParisioComments: There is an important error in the second part of the manuscript, where, contrary to what is stated, Lorentz covariance is violatedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Quantum Physics (quant-ph)
- [100] arXiv:1906.10435 (replaced) [pdf, ps, other]
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Title: Probing the ionosphere by the pulsar B0950+08 with help of RadioAstron ground-space baselinesComments: 10 pages, 7 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [101] arXiv:1906.11765 (replaced) [pdf, other]
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Title: Disconnected pseudo-$C_\ell$ covariances for projected large-scale structure dataComments: v1: 29 pages, 15 figures, comments welcome; v2: minor changes, JCAP accepted versionJournal-ref: JCAP11(2019)043Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [102] arXiv:1906.11814 (replaced) [pdf, other]
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Title: Local determination of the Hubble constant and the deceleration parameterComments: 9 pages, 4 figures. Discussion and analysis improved, results updated to the latest SH0ES determination. Version accepted for publication in Physical Review ResearchSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [103] arXiv:1907.08094 (replaced) [pdf, other]
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Title: The galaxy bias at second order in general relativity with Non-Gaussian initial conditionsComments: 1+14+4 pages, two figures. Version accepted for publication, the conclusion and discussion remain unchangedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
- [104] arXiv:1907.13184 (replaced) [pdf, other]
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Title: Some Implications of the Leptonic Annihilation of Dark Matter: Possible Galactic Radio Emission Signatures and the Excess Radio Flux of Extragalactic OriginComments: 18 pages, 28 figures. Version accepted for publicationSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
- [105] arXiv:1908.04682 (replaced) [pdf, other]
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Title: CMB-GAN: Fast Simulations of Cosmic Microwave background anisotropy maps using Deep LearningComments: 9 pages, cosmic microwave background radiation, deep learning, generative adversarial network. arXiv admin note: text overlap with arXiv:1903.12253Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Machine Learning (cs.LG); Image and Video Processing (eess.IV)
- [106] arXiv:1908.04969 (replaced) [pdf, other]
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Title: Reflection spectra of thick accretion disksComments: 11 pages, 6 figures. v2: refereed versionJournal-ref: Mon. Not. Roy. Astron. Soc. 491, 417-426 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [107] arXiv:1908.06953 (replaced) [pdf, other]
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Title: Neutrino Fluence from Gamma-Ray Bursts: Off-Axis View of Structured JetsComments: version published in MNRAS 490, 4935-4943 (2019)Journal-ref: MNRAS 490, 4935-4943 (2019)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph)
- [108] arXiv:1909.04435 (replaced) [pdf, other]
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Title: The connection between merging double compact objects and the Ultraluminous X-ray SourcesAuthors: Samaresh Mondal, Krzysztof Belczyński, Grzegorz Wiktorowicz, Jean-Pierre Lasota, Andrew R. KingComments: 15 pages, 7 figures, Accepted in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
- [109] arXiv:1909.04735 (replaced) [pdf, other]
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Title: Indirect effects of dark matterComments: 20 pages, 14 figuresJournal-ref: International Journal of Modern Physics D, Volume 28, Issue 13, 1941011 (2019)Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
- [110] arXiv:1909.05852 (replaced) [pdf, other]
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Title: A gravitational lensing detection of filamentary structures connecting luminous red galaxiesAuthors: Qianli Xia, Naomi Robertson, Catherine Heymans, Alexandra Amon, Marika Asgari, Yan-Chuan Cai, Thomas Erben, Joachim Harnois-Déraps, Hendrik Hildebrandt, Arun Kannawadi, Konrad Kuijken, Peter Schneider, Cristóbal Sifón, Tilman Tröster, Angus H. WrightComments: 13 pages, 8 figures, accepted for publication in A&ASubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [111] arXiv:1909.06381 (replaced) [pdf, other]
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Title: Dynamical Friction in a Fuzzy Dark Matter UniverseAuthors: Lachlan Lancaster, Cara Giovanetti, Philip Mocz, Yonatan Kahn, Mariangela Lisanti, David N. SpergelComments: 41 pages, 11 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
- [112] arXiv:1909.09052 (replaced) [pdf, other]
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Title: Cosmic Ray Small-Scale Anisotropies in Quasi-Linear TheoryComments: 12 pages, 2 figures; accepted for publication in JCAPSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [113] arXiv:1909.09222 (replaced) [pdf, other]
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Title: Large- and Medium-Scale Anisotropies in the Arrival Directions of Cosmic Rays observed with KASCADE-GrandeAuthors: Markus AhlersComments: version published in Astrophys.J. 886 (2019) no.1, L18Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph)
- [114] arXiv:1909.11105 (replaced) [pdf, other]
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Title: The chemistry of stars in the bar of the Milky WayComments: 7 pages, 6 figures. Accepted by A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
- [115] arXiv:1909.12718 (replaced) [pdf, other]
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Title: Finite tidal effects in GW170817: Observational evidence or model assumptions?Comments: 16 pages, 12 figuresJournal-ref: Phys. Rev. D 100, 103023 (2019)Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
- [116] arXiv:1910.00955 (replaced) [pdf, other]
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Title: An arm length stabilization system for KAGRA and future gravitational-wave detectorsAuthors: T. Akutsu, M. Ando, K. Arai, K. Arai, Y. Arai, S. Araki, A. Araya, N. Aritomi, Y. Aso, S. Bae, Y. Bae, L. Baiotti, R. Bajpai, M. A. Barton, K. Cannon, E. Capocasa, M. Chan, C. Chen, K. Chen, Y. Chen, H. Chu, Y-K. Chu, K. Doi, S. Eguchi, Y. Enomoto, R. Flaminio, Y. Fujii, M. Fukunaga, M. Fukushima, G. Ge, A. Hagiwara, S. Haino, K. Hasegawa, H. Hayakawa, K. Hayama, Y. Himemoto, Y. Hiranuma, N. Hirata, E. Hirose, Z. Hong, B. H. Hsieh, G-Z. Huang, P. Huang, Y. Huang, B. Ikenoue, S. Imam, K. Inayoshi, Y. Inoue, K. Ioka, Y. Itoh, K. Izumi, K. Jung, P. Jung, T. Kajita, M. Kamiizumi, S. Kanbara, N. Kanda, G. Kang, K. Kawaguchi, N. Kawai, T. Kawasaki, C. Kim, J. C. Kim, W. S. Kim, Y.-M. Kim, N. Kimura, N. Kita, H. Kitazawa, Y. Kojima, K. Kokeyama, K. Komori, A. K. H. Kong, K. Kotake, C. Kozakai, R. Kozu, et al. (131 additional authors not shown)Comments: 21 pages, 8figuresSubjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM); General Relativity and Quantum Cosmology (gr-qc)
- [117] arXiv:1910.01522 (replaced) [pdf, ps, other]
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Title: Formation of close binaries by disc fragmentation and migration, and its statistical modelingComments: Accepted by MNRAS; 15 pages, 11 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
- [118] arXiv:1910.07270 (replaced) [pdf, ps, other]
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Title: Thermal emission from the amorphous dust: An alternative possibility of the origin of the anomalous microwave emissionComments: Accepted for publication in PASJ; 39 pages, 11 figures, 3 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [119] arXiv:1911.01390 (replaced) [pdf, other]
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Title: Physical properties of the fluorine and neutron-capture element rich PN Jonckheere900Authors: Masaaki Otsuka (1), Siek Hyung (2) ((1) Okayama Observatory, Kyoto Univ., (2) Chungbuk National Univ.)Comments: 22 pages, 11 figures, accepted for publication by MNRAS. fi8 is replaced with the new oneSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
- [120] arXiv:1911.02657 (replaced) [pdf, ps, other]
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Title: Gravitational leptogenesis with kination and gravitational reheatingComments: 15 pagesSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
- [121] arXiv:1911.02979 (replaced) [pdf, other]
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Title: Estimating trajectories of meteors: an observational Monte Carlo approach -- I. TheoryComments: Accepted for publication in MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [122] arXiv:1911.10853 (replaced) [pdf, other]
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Title: Disks Around T Tauri Stars with SPHERE (DARTTS-S) II: Twenty-one new polarimetric images of young stellar disksAuthors: Antonio Garufi, Henning Avenhaus, Sebastian Perez, Sascha P. Quanz, Rob G. van Holstein, Gesa H.-M. Bertrang, Simon Casassus, Lucas Cieza, David A. Principe, Gerrit van der Plas, Alice ZurloComments: Accepted for publication by A&A. 14 pages, 7 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [123] arXiv:1911.12114 (replaced) [pdf, other]
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Title: Exoplanet Vision 2050Authors: René Heller (1), László Kiss ((1) Max Planck Institute for Solar System Research, Göttingen (GER), (2) Konkoly Observatory, Budapest (HUN))Comments: exoplanet counts updated to include WFIRST; based on an invited talk (RH) at the "Exoplanet Vision 2050" workshop, Konkoly Observatory, 21. Nov. 2019; 2 col. figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [124] arXiv:1911.12228 (replaced) [pdf, other]
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Title: Interstellar Asteroid Rotation with the Mechanical Torque Produced by Interstellar MediumAuthors: Wen Han ZhouComments: 7 pages, 9 figures. Comments are welcome!Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [125] arXiv:1911.12357 (replaced) [pdf, other]
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Title: The Formation of a 70 Msun Black Hole at High MetallicityAuthors: K.Belczynski, R.Hirschi, E.A.Kaiser, Jifeng Liu, J.Casares, Youjun Lu, R.O'Shaughnessy, A.Heger, S.JusthamComments: amended references and the discussion of stellar windsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
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