Astrophysics
New submissions
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New submissions for Fri, 17 Apr 20
- [1] arXiv:2004.07244 [pdf, other]
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Title: The $γ$-ray deposition histories of core-collapse supernovaeComments: 28 pages, 12 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The $\gamma$-ray deposition history in an expanding supernova (SN) ejecta has been mostly used to constrain models for Type Ia SN. Here we expand this methodology to core-collapse SNe, including stripped envelope (SE; Type Ib/Ic/IIb) and Type IIP SNe. We construct bolometric light curve using photometry from the literature and we use the Katz integral to extract the $\gamma$-ray deposition history. We recover the tight range of $\gamma$-ray escape times, $t_0\approx30-45\,\textrm{day}$, for Type Ia SNe, and we find a new tight range $t_0\approx80-140\,\textrm{day}$, for SE SNe. Type IIP SNe are clearly separated from other SNe types with $t_0\gtrsim400\,\textrm{day}$, and there is a possible negative correlation between $t_0$ and the synthesized $^{56}$Ni mass. We find that the typical masses of the synthesized $^{56}$Ni in SE SNe are larger than those in Type IIP SNe, in agreement with the results of Kushnir (2015). This disfavors progenitors with the same initial mass range for these explosions. We recover the observed values of $ET$, the time-weighted integrated luminosity from cooling emission, for Type IIP, and we find hints of non zero $ET$ values in some SE SNe. We apply a simple $ \gamma$-ray radiation transfer code to calculate the $\gamma$-ray deposition histories of models from the literature, and we show that the observed histories are a powerful tool for constraining models.
- [2] arXiv:2004.07246 [pdf, other]
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Title: Separating Accretion and Mergers in the Cosmic Growth of Black Holes with X-ray and Gravitational Wave ObservationsComments: Accepted for publication in The Astrophysical Journal. 12 pages, 5 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)
Black holes across a broad range of masses play a key role in the evolution of galaxies. The initial seeds of black holes formed at $z \sim 30$ and grew over cosmic time by gas accretion and mergers. Using observational data for quasars and theoretical models for the hierarchical assembly of dark matter halos, we study the relative importance of gas accretion and mergers for black hole growth, as a function of redshift ($0<z<10$) and black hole mass ($ 10^3 \, \mathrm{M_{\odot}} < M_{\bullet} < 10^{10} \, \mathrm{M_{\odot}}$). We find that: (i) growth by accretion is dominant in a large fraction of the parameter space, especially at $M_{\bullet} > 10^8 \, \mathrm{M_{\odot}}$ and $z>6$; (ii) growth by mergers is dominant at $M_{\bullet} < 10^5 \, \mathrm{M_{\odot}}$ and $z>5.5$, and at $M_{\bullet} > 10^8 \, \mathrm{M_{\odot}}$ and $z<2$. As the growth channel has direct implications for the black hole spin (with gas accretion leading to higher spin values), we test our model against $\sim 20$ robust spin measurements available thus far. As expected, the spin tends to decline towards the merger-dominated regime, thereby supporting our model. The next generation of X-ray and gravitational wave observatories (e.g. Lynx, Athena and LISA) will map out populations of black holes up to very high redshift ($z\sim 20)$, covering the parameter space investigated here in almost its entirety. Their data will be instrumental to providing a clear picture of how black holes grew across cosmic time.
- [3] arXiv:2004.07250 [pdf, other]
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Title: 2MASS J04435686+3723033 B: A Young Companion at the Substellar Boundary with Potential Membership in the $β$ Pictoris Moving GroupComments: 18 pages, 18 figures, Accepted to ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
We present a detailed characterization of 2MASS J04435750+3723031, a low-mass companion orbiting the young M2 star, 2MASS J04435686+3723033, at 7.6 arcseconds (550 AU) with potential membership in the 23 Myr $\beta$ Pictoris moving group ($\beta$PMG). Using near-infrared spectroscopy of the companion from IRTF/SpeX we have found a spectral type of M6 $\pm$ 1 and indications of youth through age-sensitive absorption lines and a low surface gravity index (VL-G). A young age is supported by H$\alpha$ emission and lithium absorption in the host. We re-evaluate the membership of this system and find that it is a marginally consistent kinematic match to the $\beta$PMG using $Gaia$ parallaxes and new radial velocities for the host and companion. If this system does belong to the $\beta$PMG, it would be a kinematic outlier and the companion would be over-luminous compared to other similar ultracool objects like PZ Tel B; this would suggest 2M0443+3723 B could be a close brown dwarf binary ($\approx$52+52 M$_\mathrm{Jup}$ if equal-flux, compared with 99 $\pm$ 5 M$_\mathrm{Jup}$ if single), and would make it the sixth substellar companion in this group. To test this hypothesis, we acquired NIR AO images with Keck II/NIRC2, but they do not resolve the companion to be a binary down to the diffraction limit of $\sim$3 AU. If 2M0443+3723 AB does not belong to any moving group then its age is more uncertain. In this case it is still young ($\lesssim$30 Myr), and the implied mass of the companion would be between $\sim$30--110 M$_\mathrm{Jup}$.
- [4] arXiv:2004.07252 [pdf, other]
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Title: H- and Dissociation in Ultra-hot Jupiters: A Retrieval Case Study of WASP-18bComments: 19 pages, 10 figures, accepted for publication in The Astronomical JournalSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Atmospheres of a number of ultra-hot Jupiters (UHJs) with temperatures $\gtrsim$2000~K have been observed recently. Many of these planets show largely featureless thermal spectra in the near-infrared observed with the HST WFC3 spectrograph (1.1-1.7~$\mu$m) even though this spectral range contains strong H$_2$O opacity. Recent works have proposed the possibility of H- opacity masking the H$_2$O feature and/or thermal dissociation of H$_2$O causing its apparent depletion at the high temperatures of UHJs. In this work we test these hypotheses using observations of the exoplanet WASP-18b as a case study. We report detailed atmospheric retrievals of the planet using the HyDRA retrieval code, extended to include the effects of H- opacity and thermal dissociation. We report constraints on the H$_2$O, CO and H- abundances as well as the pressure-temperature profile of the dayside atmosphere for retrievals with and without H-/dissociation for each dataset. We find that the H$_2$O and H- abundances are relatively unconstrained given the featureless WFC3 spectra. We do not conclusively detect H- in the planet contrary to previous studies which used equilibrium models to infer its presence. The constraint on the CO abundance depends on the combination of WFC3 and Spitzer data, ranging from solar to super-solar CO values. We additionally see signs of a thermal inversion from two of the datasets. Our study demonstrates the potential of atmospheric retrievals of UHJs including the effects of H- and thermal dissociation of molecules.
- [5] arXiv:2004.07256 [pdf, ps, other]
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Title: Quantifying resolution in cosmological N-body simulations using self-similarityComments: 14 pages, 9 figures, submitted, comments welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We demonstrate that testing for self-similarity in scale-free simulations provides an excellent tool to quantify the resolution at small scales of cosmological N-body simulations. Analysing two-point correlation functions measured in simulations using ABACUS, we show how observed deviations from self-similarity reveal the range of time and distance scales in which convergence is obtained. While the well-converged scales show accuracy below 1 percent, our results show that, with a small force softening length, the spatial resolution is essentially determined by the mass resolution. At later times the lower cut-off scale on convergence evolves in comoving units as $a^{-1/2}$ ($a$ being the scale factor), consistent with a hypothesis that it is set by two-body collisionality. A corollary of our results is that N-body simulations, particularly at high red-shift, contain a significant spatial range in which clustering appears converged with respect to the time-stepping and force softening but has not actually converged to the physical continuum result. The method developed can be applied to determine the resolution of any clustering statistic and extended to infer resolution limits for non-scale-free simulations.
- [6] arXiv:2004.07257 [pdf, other]
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Title: Constraining the radial drift of millimeter-sized grains in the protoplanetary disks in LupusAuthors: L. Trapman, M. Ansdell, M.R. Hogerheijde, S. Facchini, C.F. Manara, A. Miotello, J.P. Williams, S. BrudererComments: 17 pages, 11 figures, accepted in A&ASubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Recent ALMA surveys of protoplanetary disks have shown that for most disks the extent of the gas emission is greater than the extent of the thermal emission of the millimeter-sized dust. Both line optical depth and the combined effect of radially dependent grain growth and radial drift may contribute to this observed effect. For a sample of 10 disks from the Lupus survey we investigate how well dust-based models without radial dust evolution reproduce the observed 12CO outer radius, and determine whether radial dust evolution is required to match the observed gas-dust size difference. We used the thermochemical code DALI to obtain 12CO synthetic emission maps and measure gas and dust outer radii (Rco, Rmm) using the same methods as applied to the observations, which were compared to observations on a source-by-source basis. For 5 disks we find that the observed gas-dust size difference is larger than the gas-dust size difference due to optical depth, indicating that we need both dust evolution and optical depth effects to explain the observed gas-dust size difference. For the other 5 disks the observed gas-dust size difference can be explained using only line optical depth effects. We also identify 6 disks not included in our initial sample but part of a survey of the same star-forming region that show significant 12CO emission beyond 4 x Rmm. These disks, for which no Rco is available, likely have gas-dust size differences greater than 4 and are difficult to explain without substantial dust evolution. Our results suggest that radial drift and grain growth are common features among both bright and fain disks. The effects of radial drift and grain growth can be observed in disks where the dust and gas radii are significantly different, while more detailed models and deeper observations are needed to see this effect in disks with smaller differences.
- [7] arXiv:2004.07258 [pdf, other]
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Title: Do stellar-mass and super-massive black holes have similar dining habits?Comments: Accepted for publication in Astronomy & AstrophysicsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Through the years numerous attempts have been made to connect the phenomenology and physics of mass accretion onto stellar-mass and super-massive black holes in a scale-invariant fashion. In this paper, we explore this connection at the radiatively-efficient (and non-jetted) end of accretion modes by comparing the relationship between the luminosity of the accretion disk and corona in the two source classes. We analyse 458 RXTE-PCA archival observations of the X-ray binary (XRB) GX339-4 focusing on the soft and soft-intermediate states, which have been suggested to be analogous to radiatively efficient AGN. The observed scatter in the $\log L_{disk}-\log L_{corona}$ relationship of GX339-4 is high ($\sim0.43\,$dex) and significantly larger than in a representative sample of radiatively-efficient, non- or weakly-jetted AGN ($\sim0.30\,$dex). On the face of it, this would appear contrary to the hypothesis that the systems simply scale with mass. On the other hand we also find that GX339-4 and our AGN sample show different $\dot{m}$ and $\Gamma$ distributions, with the latter being broader in GX339-4 (dispersion of $\sim0.16$ cf. $\sim0.08$ for AGN). GX339-4 also shows an overall softer slope, with mean $\sim2.20$ as opposed to $\sim2.07$ for the AGN sample. Remarkably, once similarly broad $\Gamma$ and $\dot{m}$ distributions are selected, the AGN sample overlaps nicely with GX339-4 observations in the mass-normalised $\log L_{disk}-\log L_{corona}$ plane, with a scatter of $\sim0.30-0.33\,$dex. This indicates that a mass-scaling of properties might hold after all, with our results being consistent with the disk-corona systems in AGN and XRBs exhibiting the same physical processes, albeit under different conditions for instance in terms of temperature, optical depth and/or electron energy distribution in the corona, heating-cooling balance, coronal geometry and/or black hole spin.
- [8] arXiv:2004.07261 [pdf, other]
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Title: Untangling the Galaxy. II. Structure within 3 kpcComments: 16 pages, 13 figures, submitted to AJ. Interactive plot is available at this http URL and the code repository is at this https URLSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
We present the results of the hierarchical clustering analysis of the Gaia DR2 data to search for clusters, co-moving groups, and other stellar structures. The current paper builds on the sample from the previous work, extending it in distance from 1 kpc to 3 kpc, increasing the number of identified structures up to 8292. To aid in the analysis of the population properties, we developed a neural network called Auriga to robustly estimate the age, extinction, and distance of a stellar group based on the input photometry and parallaxes of the individual members. We apply Auriga to derive the properties of not only the structures found in this paper, but also previously identified open clusters. Through this work, we examine the temporal structure of the spiral arms. Specifically, we find that the Sagittarius arm has moved by >500 pc in the last 100 Myr, and the Perseus arm has been experiencing a relative lull in star formation activity over the last 25 Myr. We confirm the findings from the previous paper on the transient nature of the spiral arms, with the timescale of transition of a few 100 Myr. Finally, we find a peculiar ~1 Gyr old stream of stars that appears to be heliocentric. It is unclear what is the origin of it.
- [9] arXiv:2004.07263 [pdf, other]
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Title: Robustness of baryon acoustic oscillations constraints to beyond-$Λ$CDM cosmologiesComments: 21 pages, 4 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Baryon acoustic oscillations (BAO) provide a robust standard ruler, and can be used to constrain the expansion history of the Universe at low redshift. Standard BAO analyses return a model-independent measurement of the expansion rate and the angular diameter distance as function of redshift, normalized by the sound horizon at radiation drag. However, this methodology relies on anisotropic distance distortions of a fixed, pre-computed template (obtained in a given fiducial cosmology) in order to fit the observations. Therefore, it may be possible that extensions to the consensus $\Lambda$CDM add contributions to the BAO feature that cannot be captured by the template fitting. We perform mock BAO fits to power spectra computed assuming cosmological models which modify the growth of perturbations prior to recombination in order to test the robustness of the standard BAO analysis. We find no significant bias in the BAO analysis for the models under study ($\Lambda$CDM with a free effective number of relativistic species, early dark energy, and a model with interactions between neutrinos and a fraction of the dark matter), even for cases which do not provide a good fit to Planck measurements of the CMB power spectra. This result supports the use of the standard BAO analysis and its measurements to perform cosmological parameter inference and to constrain exotic models. In addition, we provide a methodology to reproduce our study for different models and surveys, as well as discuss different options to handle eventual biases in the BAO measurements.
- [10] arXiv:2004.07273 [pdf, other]
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Title: Measuring distances to low-luminosity galaxies using surface brightness fluctuationsComments: 29 pages, 15 figures, submitted to ApJ. Comments welcome!Subjects: Astrophysics of Galaxies (astro-ph.GA)
We present an in-depth study of surface brightness fluctuations (SBFs) in low-luminosity stellar systems. Using the MIST models, we compute theoretical predictions for absolute SBF magnitudes in the LSST, HST, and proposed WFIRST filter systems. We compare our calculations to the observed SBF magnitudes of dwarf galaxies that have independent distance measurements from the tip of the red giant branch method. Consistent with previous studies, we find that single-age population models show excellent agreement with the observed SBF-color relation of low-mass galaxies with $0.5 \lesssim g - i \lesssim 0.9$. For bluer galaxies, the observed relation is better fit by models with composite stellar populations. To study SBF recovery from low-luminosity galaxies, we perform detailed image simulations in which we inject fully populated model galaxies into deep ground-based images from real observations. We demonstrate that measurements of SBF magnitudes from these simulated data correspond to the theoretical values with negligible bias ($\lesssim0.01$ mag). We then use the simulations to show that LSST will provide data of sufficient quality and depth to measure SBF distances with precisions of ${\sim}10$-20% to ultra-faint $\left(\mathrm{10^4 \leq M_\star/M_\odot \leq 10^5}\right)$ and low-mass classical ($\leq10^7$ M$_\odot$) dwarf galaxies out to ${\sim}4$ Mpc and ${\sim}25$ Mpc, respectively, within the first few years of its deep-wide-fast survey. Many systematic uncertainties remain, including an irreducible "sampling scatter" in the SBFs of ultra-faint dwarfs due to their undersampled stellar mass functions. We nonetheless conclude that SBFs in the new generation of wide-field imaging surveys have the potential to play a critical role in the efficient confirmation and characterization of dwarf galaxies in the nearby universe.
- [11] arXiv:2004.07274 [pdf, other]
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Title: Painting a portrait of the Galactic disc with its stellar clustersAuthors: T. Cantat-Gaudin, F. Anders, A. Castro-Ginard, C. Jordi, M. Romero-Gomez, C. Soubiran, L. Casamiquela, Y. Tarricq, A. Moitinho, A. Vallenari, A. Bragaglia, A. Krone-Martins, M. KounkelComments: 19 pages, 13 figures, to be submitted to A&ASubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
The large astrometric and photometric survey performed by the Gaia mission allows for a panoptic view of the Galactic disc and in its stellar cluster population. Hundreds of clusters were only discovered after the latest G data release (DR2) and have yet to be characterised. Here we make use of the deep and homogeneous Gaia photometry down to G=18 to estimate the distance, age, and interstellar reddening for about 2000 clusters identified with Gaia~DR2 astrometry. We use these objects to study the structure and evolution of the Galactic disc. We rely on a set of objects with well-determined parameters in the literature to train an artificial neural network to estimate parameters from the Gaia photometry of cluster members and their mean parallax. We obtain reliable parameters for 1867 clusters. Our new homogeneous catalogue confirms the relative lack of old clusters in the inner disc (with a few notable exceptions). We also quantify and discuss the variation of scale height with cluster age, and detect the Galactic warp in the distribution of old clusters. This work results in a large and homogenous cluster catalogue. However, the present sample is still unable to trace the Outer spiral arm of the Milky Way, which indicates that the outer disc cluster census might still be incomplete.
- [12] arXiv:2004.07279 [pdf, other]
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Title: Centrifugally Driven Mass Loss and Outbursts of Massive StarsComments: 18 pages, 13 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Rotation and mass loss are crucially interlinked properties of massive stars, strongly affecting their evolution and ultimate fate. Massive stars rotating near their breakup limit shed mass centrifugally, creating Be stars with circumstellar disks and possibly driving outbursts. Using the MESA stellar evolution code, we examine the effects of efficient angular momentum transport on the main sequence and post-main sequence rotational evolution of massive stars. In rapid rotators, angular momentum transported from the contracting core to the expanding envelope can spin up the surface layers past the breakup rate, particularly for stars near (or beyond) the end of the main sequence and in low-metallicity environments. We also demonstrate that centrifugal instabilities could arise in rapidly rotating massive stars, potentially triggering the S Doradus outbursts observed in luminous blue variable stars. Prior mass accretion from a binary companion increases both the likelihood and the intensity of centrifugal mass loss. We discuss implications for massive stellar evolution, Be stars, and luminous blue variables.
- [13] arXiv:2004.07283 [pdf, other]
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Title: First Light And Reionisation Epoch Simulations (FLARES) I: Environmental Dependence of High-Redshift Galaxy EvolutionAuthors: Christopher C. Lovell, Aswin P. Vijayan, Peter A. Thomas, Stephen M. Wilkins, David J. Barnes, Dimitrios Irodotou, Will RoperComments: 20 pages, 19 figures, submitted to MNRAS. Comments welcome!Subjects: Astrophysics of Galaxies (astro-ph.GA)
We introduce the First Light And Reionisation Epoch Simulations (FLARES), a suite of zoom simulations using the EAGLE model. We resimulate a range of overdensities during the Epoch of Reionisation (EoR) in order to build composite distribution functions, as well as explore the environmental dependence of galaxy formation and evolution during this critical period of galaxy assembly. The regions are selected from a large $(3.2 \;\mathrm{cGpc})^{3}$ parent volume, based on their overdensity within a sphere of radius $14\,h^{-1}\;\mathrm{cMpc}$. We then resimulate with full hydrodynamics, and employ a novel weighting scheme that allows the construction of composite distribution functions that are representative of the full parent volume. This significantly extends the dynamic range compared to smaller volume periodic simulations. We present an analysis of the galaxy stellar mass function (GSMF), the star formation rate distribution function (SFRF) and the star forming sequence (SFS) predicted by \flares, and compare to a number of observational and model constraints. We also analyse the environmental dependence over an unprecedented range of overdensity. Both the GSMF and the SFRF exhibit a clear double-Schechter form, up to the highest redshifts ($z = 10$). We also find no environmental dependence of the SFS normalisation. The increased dynamic range probed by FLARES will allow us to make predictions for a number of large area surveys that will probe the EoR in coming years, such as WFIRST and Euclid.
- [14] arXiv:2004.07289 [pdf, other]
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Title: Microlensing optical depth and event rate in the OGLE-IV Galactic plane fieldsAuthors: Przemek Mroz, Andrzej Udalski, Michal K. Szymanski, Igor Soszynski, Pawel Pietrukowicz, Szymon Kozlowski, Jan Skowron, Radoslaw Poleski, Krzysztof Ulaczyk, Mariusz Gromadzki, Krzysztof Rybicki, Patryk Iwanek, Marcin WronaComments: submittedSubjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Searches for gravitational microlensing events are traditionally concentrated on the central regions of the Galactic bulge but it is expected that many microlensing events should occur in the Galactic plane, far from the Galactic Center. Owing to the difficulty in conducting high-cadence observations of the Galactic plane over its vast area, necessary for the detection of microlensing events, their global properties were hitherto unknown. Here, we present results of the first comprehensive search for microlensing events in the Galactic plane. We searched an area of almost 3,000 square degrees along the Galactic plane (|b|<7 deg, 0<l<50 deg, 190<l<360 deg) observed by the Optical Gravitational Lensing Experiment (OGLE) during 2013-2019 and detected 630 events. We demonstrate that the mean Einstein timescales of Galactic plane microlensing events are on average three times longer than those of Galactic bulge events, with little dependence on the Galactic longitude. We also measure the microlensing optical depth and event rate as a function of Galactic longitude and demonstrate that they exponentially decrease with the angular distance from the Galactic Center (with the characteristic angular scale length of 32 deg). The average optical depth decreases from $0.5\times 10^{-6}$ at l=10 deg to $1.5\times 10^{-8}$ in the Galactic anticenter. We also find that the optical depth in the longitude range 240<l<330 deg is asymmetric about the Galactic equator, which we interpret as a signature of the Galactic warp.
- [15] arXiv:2004.07291 [pdf, ps, other]
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Title: Kinematics of T Tauri Stars Close to the Sun from the Gaia DR2 CatalogueAuthors: V. V. BobylevComments: 17 pages, 4 figures, 3 tablesJournal-ref: Astronomy Letters, 2020, Vol. 46, No 2, pp. 131-143Subjects: Astrophysics of Galaxies (astro-ph.GA)
The spatial and kinematic properties of a large sample of young T Tauri stars from the solar neighborhood 500 pc in radius have been studied. The following parameters of the position ellipsoid have been determined from the most probable members of the Gould Belt: its sizes are $350\times 270 \times 87$~pc and it is oriented at an angle of $14\pm1^\circ$ to the Galactic plane with a longitude of the ascending node of $297\pm1^\circ$. An analysis of the motions of stars from this sample has shown that the residual velocity ellipsoid with principal semiaxes $\sigma_{1,2,3}=(8.87,5.58,3.03)\pm(0.10,0.20,0.04)$~km s$^{-1}$ is oriented at an angle of $22\pm1^\circ$ to the Galactic plane with a longitude of the ascending node of $298\pm2^\circ$. It has been established that much of the expansion effect (kinematic $K$ effect) typical for Gould Belt stars, 5--6 km s$^{-1}$ kpc$^{-1}$, can be explained by the influence of a Galactic spiral density wave with a radial perturbation amplitude $f_R\sim5$ km s$^{-1}$.
- [16] arXiv:2004.07305 [pdf, other]
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Title: Internal Kinematics of M10 and M71Comments: 12 pages, 7 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We present a study of the internal kinematics of two globular clusters, M10 (NGC 6254) and M71 (NGC 6838), using individual radial velocity (RV) measurements obtained from observations using the Hydra multi-object spectrograph on the WIYN 3.5 m telescope. We measured 120 RVs for stars in M10, of which 107 were determined to be cluster members. In M71, we measured 82 RVs and determined 78 of those measurements belonged to cluster members. Using the cluster members, we determine a mean RV of $75.9 \pm 4.0$ (s.d.) km s$^{-1}$ and $-22.9 \pm 2.2$ (s.d.) km s$^{-1}$ for M10 and M71, respectively. We combined the Hydra RV measurements with literature samples and performed a line-of-sight rotational analysis on both clusters. Our analysis has not revealed a statistically significant rotation in either of these clusters with the exception of the inner region (10\arcsec - 117\arcsec) of M10 for which we find hints of a marginally significant rotation with amplitude V$_{rot} = 1.14 \pm 0.18$ km s$^{-1}$. For M10, we calculate a central velocity dispersion of $\sigma_{0} = 5.44 \pm 0.61$ km s$^{-1}$, which gives a ratio of the amplitude of rotation to the central velocity dispersion $V_{rot}/\sigma_{0} = 0.21 \pm 0.04$. We also explored the rotation of the multiple stellar populations identified in M10 and M71 and found rotation (or lack thereof) in each population consistent with each other and the cluster global rotation signatures.
- [17] arXiv:2004.07315 [pdf, other]
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Title: Hard Synchrotron Spectra from Magnetically Dominated Plasma TurbulenceSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)
Synchrotron emission from astrophysical nonthermal sources usually assumes that the emitting particles are isotropic. By means of large-scale two- and three-dimensional particle-in-cell simulations, we demonstrate that the dissipation of magnetically-dominated ($\sigma_0\gg1$) turbulence in pair plasmas leads to strongly anisotropic particle distributions. At Lorentz factors $\sim \sigma_0 \gamma_{th0}$ (here, $\gamma_{th0}$ is the initial Lorentz factor), the particle velocity is preferentially aligned with the local magnetic field; instead, the highest energy particles are roughly isotropic. This energy-dependent anisotropy leads to a synchrotron spectral flux $\nu F_\nu\propto \nu^s$ that is much harder than for isotropic particles. Remarkably, for $\sigma_0\gg1$ we find that the solid-angle-averaged spectral slope in the slow cooling regime is $s\sim 0.5-0.7$ for a wide range of turbulence fluctuations, $0.25\lesssim \delta B_{\rm rms0}^2/B_0^2\lesssim 4$, despite significant variations in the power-law energy spectrum of nonthermal particles. This is because weaker turbulence levels imprint a stronger degree of anisotropy, thereby counteracting the effect of the steeper particle spectrum. The synchrotron spectral slope may be even harder, $s\gtrsim 0.7$, if the observer is in the plane perpendicular to the mean magnetic field. Our results are independent of domain size and dimensionality. Our findings may help explaining the origin of hard synchrotron spectra of astrophysical nonthermal sources, most notably the radio spectrum of Pulsar Wind Nebulae.
- [18] arXiv:2004.07327 [pdf, ps, other]
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Title: Astronomical masers and Dicke's superradianceComments: 15 pages, 9 figures, accepted MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Optics (physics.optics)
We consider the radiation properties and processes of a gas with a population inversion using the formalism based on the Maxwell-Bloch equations. We focus on the maser action and Dicke's superradiance to establish their relationship in the overall radiation process during the temporal evolution of the system as a function of position. We show that the maser action and superradiance are not competing phenomena but are rather complementary, and define two distinct limits for the intensity of radiation. Masers characterise the quasi-steady state limit, when the population inversion density and the polarisation amplitude vary on time-scales longer than those of non-coherent processes affecting their evolution (e.g., collisions), while superradiance defines the fast transient regime taking place when these conditions are reversed. We show how a transition from a maser regime to superradiance will take place whenever a critical threshold for the column density of the population inversion is reached, at which point a strong level of coherence is established in the system and a powerful burst of radiation can ensue during the transient regime. This critical level also determines the spatial region where a transition from the unsaturated to the saturated maser regimes will take place; superradiance can thus be seen as the intermediary between the two. We also quantify the gain in radiation intensity attained during the superradiance phase relative to the two maser regimes, and show how the strong coherence level during superradiance is well suited to explain observations that reveal intense and fast radiation flares in maser-hosting regions.
- [19] arXiv:2004.07328 [pdf, other]
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Title: The Reduced Proper Motion selected halo: methods and description of the catalogueComments: 16 pages, 17 figures, submittedSubjects: Astrophysics of Galaxies (astro-ph.GA)
The Gaia mission has provided the largest ever astrometric chart of the Milky Way. Using it to map the Galactic halo is helpful for disentangling its merger history. The identification of halo stars in Gaia DR2 with reliable distance estimates requires special methods because such stars are typically farther away and scarce. We apply the reduced proper motion (RPM) method to identify halo main sequence stars on the basis of Gaia photometry and proper motions. Using the colour-absolute-magnitude relation for this type of stars, we calculate photometric distances. Our selection results in a set of $\sim10^7$ tentative main sequence halo stars with typical distance uncertainties of $7\%$ and with median velocity errors of 20 km/s. The median distance of our sample is $\sim 4.4$ kpc, with the faintest stars located at $\sim 16$ kpc. The spatial distribution of the stars in our sample is centrally concentrated. Visual inspection of the mean velocities of stars on the sky reveals large-scale patterns as well as clear imprints of the GD-1 stream and tentative hints of the Jhelum and Leiptr streams. Incompleteness and selection effects limit our ability to interpret the patterns reliably as well as to identify new substructures. We define a pseudo-velocity space by setting to zero the line-of-sight velocities of our sample stars. In this space, we recover several known structures such as the footprint of Gaia-Enceladus (i.e. the Gaia-Sausage) as well as the Helmi streams and some other retrograde substructures (Sequoia, Thamnos). We show that the two-point velocity correlation function reveals significant clustering on scales smaller than 100 km/s, of similar amplitude as found for the 6D Gaia halo sample. This clustering indicates the presence of nearby streams that are predominantly phase-mixed.
- [20] arXiv:2004.07345 [pdf, other]
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Title: Active-Region Tilt Angles from White-Light Images and Magnetograms: The Role of Magnetic TonguesSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The presence of elongations in active region (AR) polarities, called magnetic tongues, are mostly visible during their emergence phase. AR tilts have been measured thoroughly using long-term white-light (WL) databases, sometimes combined with magnetic field information. Since the influence of magnetic tongues on WL tilt measurements has not been taken into account before, we aim to investigate their role in tilt-angle values and to compare them with those derived from LOS magnetograms. We apply four methods to compute the tilt angle of generally bipolar ARs: one applies the k-means algorithm to WL data, a second one includes the magnetic field sign of the polarities to WL data, and a third one uses the magnetic flux-weighted center of each polarity. The tilt values computed in any of these ways are affected by the presence of magnetic tongues. Therefore, we apply the newly developed Core Field Fit Estimator (CoFFE) method to separate the magnetic flux in the tongues from that in the AR core. We compare the four computed tilt-angle values, as well as these with the ones reported in long-term WL databases. For ARs with low magnetic flux tongues the different methods report consistent tilt-angle values. But for ARs with high flux tongues there are noticeable discrepancies between all methods indicating that magnetic tongues affect differently WL and magnetic data. However, in general, CoFFE achieves a better estimation of the main bipole tilt because it removes both the effect of tongues as well as the emergence of secondary bipoles when it occurs in between the main bipole magnetic polarities.
- [21] arXiv:2004.07366 [pdf, other]
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Title: Spatially Resolved Chandra Spectroscopy of the Large Magellanic Cloud Supernova Remnant N132DComments: 32 pages, 28 figures, 10 tables, accepted for ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
We perform detailed spectroscopy of the X-ray brightest supernova remnant (SNR) in the Large Magellanic Cloud (LMC), N132D, using Chandra archival observations. By analyzing the spectra of the entire well-defined rim, we determine the mean abundances for O, Ne, Mg, Si, S and Fe for the local LMC environment. We find evidence of enhanced O on the north-western and S on the north-eastern blast wave. By analyzing spectra interior to the remnant, we confirm the presence of a Si-rich relatively hot plasma (> 1.5 kev) that is also responsible for the Fe K emission. Chandra images show that the Fe K emission is distributed throughout the interior of the southern half of the remnant but does not extend out to the blast wave. We estimate the progenitor mass to be $15\pm5\,M_{\odot}$ using abundance ratios in different regions that collectively cover a large fraction of the remnant, as well as from the radius of the forward shock compared with models of an explosion in a cavity created by stellar winds. We fit ionizing and recombining plasma models to the Fe K emission and find that the current data cannot distinguish between the two, hence the origin of the high-temperature plasma remains uncertain. Our analysis is consistent with N132D being the result of a core-collapse supernova in a cavity created by its intermediate mass progenitor.
- [22] arXiv:2004.07382 [pdf, other]
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Title: Stellar-mass black holes in young massive and open stellar clusters and their role in gravitational-wave generation IV: updated stellar-evolutionary and black hole spin models and comparisons with the LIGO-Virgo O1/O2 merger-event dataAuthors: Sambaran BanerjeeComments: 29 pages (20 pages of main text plus appendices), 11 figures. Submitted. Comments are welcomeSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
In this work, I present a set of long-term, direct, relativistic many-body computations of model dense stellar clusters with up-to-date remnant mass and natal-kick models, including pair instability and pulsation pair instability supernova (PSN and PPSN), using NBODY7 N-body simulation program. The new model implementations also incorporate natal spins of BHs, based on theoretical stellar-evolutionary models, and runtime tracking of GR merger recoils and final spins in binary black hole (BBH) mergers, based on numerical relativity. These, for the first time in a direct N-body simulation, allow for second-generation BBH mergers. The set of 65 evolutionary models have initial masses $10^4M_\odot-10^5M_\odot$, sizes 1 pc-3 pc, metallicity 0.0001-0.02, with the massive stars in primordial binaries and they represent young massive clusters (YMC) and moderately massive open clusters (OC). Such models produce dynamically-paired BBH mergers that agree well with the observed masses, mass ratios, effective spin parameters, and final spins of the LVC O1/O2 merger events and also with their overall trends and boundaries, provided BHs are born with low or no spin but spin up after undergoing a BBH merger or matter accretion onto it. In particular, the distinctly higher mass, effective spin parameter, and final spin of GW170729 merger event is naturally reproduced. The computed models also produce massive, $\sim100M_\odot$ BBH mergers with primary mass within the "PSN gap". Depending on the remnant-mass and natal-kick scenarios, such models also yield mergers involving remnants in the NS-BH "mass gap" as detected in the LVC O3. These computations also suggest that YMCs and OCs produce persistent GW sources detectable by LISA from within the $\sim100$ Mpc Local Universe. Such clusters are also capable of producing mergers with eccentricity detectable by the LIGO-Virgo.
- [23] arXiv:2004.07412 [pdf, other]
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Title: Stochastic Processes as the Origin of the Double-Power Law Shape of the Quasar Luminosity FunctionComments: 12 pages, 6 figures; accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
The Quasar Luminosity Function (QLF) offers insight into the early co-evolution of black holes and galaxies. It has been characterized observationally up to redshift $z\sim6$ with clear evidence of a double power-law shape, in contrast to the Schechter-like form of the underlying dark-matter halo mass function. We investigate a physical origin for the difference in these distributions by considering the impact of stochasticity induced by the processes that determine the quasar luminosity for a given host halo and redshift. We employ a conditional luminosity function and construct the relation between median quasar magnitude versus halo mass $M_{UV,\rm{c}}(M_{\rm{h}})$ with log-normal in luminosity scatter $\Sigma$, and duty-cycle $\epsilon_{\rm{DC}}$, and focus on high redshift $z\gtrsim4$. We show that, in order to reproduce the observed QLF, the $\Sigma=0$ abundance matching requires all of the brightest quasars to be hosted in the rarest most massive dark-matter halos (with an increasing $M_{UV,\rm{c}}/M_{\rm{h}}$ in halo mass). Conversely, for $\Sigma>0$ the brightest quasars can be over-luminous outliers hosted in relatively common dark-matter halos. In this case, the median quasar magnitude versus halo mass relation, $M_{UV,\rm{c}}$, flattens at the high-end, as expected in self-regulated growth due to feedback. We sample the parameter space of $\Sigma$ and $\epsilon_{\rm{DC}}$ and show that $M_{UV,\rm{c}}$ flattens above $M_{\rm{h}}\sim 10^{12}M_{\odot}$ for $\epsilon_{\rm{DC}}<10^{-2}$. Models with $\epsilon_{\rm{DC}}\sim1$ instead require a high mass threshold close to $M_{\rm{h}}\gtrsim10^{13}M_{\odot}$. We investigate the impact of $\epsilon_{\rm{DC}}$ and $\Sigma$ on measurements of clustering and find there is no luminosity dependence on clustering for $\Sigma>0.3$, consistent with recent observations from Subaru HSC.
- [24] arXiv:2004.07431 [pdf, other]
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Title: Colour-colour and colour-magnitude diagrams for Hot JupitersComments: 12 pages, 5 figures, accepted by MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
We use ground-based and space-based eclipse measurements for the near-infrared ($JHK\!s$) bands and Spitzer 3.6 $\mu$m and 4.5 $\mu$m bands to construct colour-colour and colour-magnitude diagrams for hot Jupiters. We compare the results with previous observations of substellar objects and find that hot Jupiters, when corrected for their inflated radii, lie near the black body line and in the same region of the colour magnitude diagrams as brown dwarfs, including low gravity dwarfs that have been previously suggested as exoplanet analogs. We use theoretical emission spectra to investigate the effects of different metallicity, C/O ratios and temperatures on the IR colours. In general we find that while differences in C/O ratio and metallicity do correspond to different locations on these diagrams, the measurement errors are too large to use this method to put strong constraints on the composition of individual objects. However, as a class hot Jupiters cluster around the location expected for solar metallicity and C/O ratio.
- [25] arXiv:2004.07449 [pdf, other]
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Title: A Precise Benchmark for Cluster Scaling Relations: Fundamental Plane, Mass Plane and IMF in the Coma Cluster from Dynamical ModelsAuthors: Shravan Shetty, Michele Cappellari, Richard M. McDermid, Davor Krajnovic, P. T. de Zeeuw, Roger L. Davies, Chiaki KobayashiComments: 16 pages, 11 figures, Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We study a sample of 148 early-type galaxies in the Coma cluster using SDSS photometry and spectra, and calibrate our results using detailed dynamical models for a subset of these galaxies, to create a precise benchmark for dynamical scaling relations in high-density environments. For these galaxies, we successfully measured global galaxy properties, modeled stellar populations, and created dynamical models, and support the results using detailed dynamical models of 16 galaxies, including the two most massive cluster galaxies, using data taken with the SAURON IFU. By design, the study provides minimal scatter in derived scaling relations due to the small uncertainty in the relative distances of galaxies compared to the cluster distance. Our results demonstrate low ($\leq$55% for 90$^{th}$ percentile) dark matter fractions in the inner 1$R_{\rm e}$ ~of galaxies. Owing to the study design, we produce the tightest, to our knowledge, IMF-$\sigma_e$ relation of galaxies, with a slope consistent with that seen in local galaxies. Leveraging our dynamical models, we transform the classical Fundamental Plane of the galaxies to the Mass Plane. We find that the coefficients of the mass plane are close to predictions from the virial theorem, and have significantly lower scatter compared to the Fundamental plane. We show that Coma galaxies occupy similar locations in the (M$_*$ - $R_{\rm e}$) and (M$_*$ - $\sigma_e$) relations as local field galaxies but are older. This, and the fact we find only three slow rotators in the cluster, is consistent with the scenario of hierarchical galaxy formation and expectations of the kinematic morphology-density relation.
- [26] arXiv:2004.07461 [pdf, ps, other]
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Title: The drivers of active region outflows into the slow solar windAuthors: David H. Brooks, Amy R. Winebarger, Sabrina Savage, Harry P. Warren, Bart De Pontieu, Hardi Peter, Jonathan W. Cirtain, Leon Golub, Ken Kobayashi, Scott W. McIntosh, David McKenzie, Richard Morton, Laurel Rachmeler, Paola Testa, Sanjiv Tiwari, Robert WalshComments: To be published in The Astrophysical Journal. Figures 1, 2, 3 and 12 are reduced resolution to meet size requirements. The original figures will appear in the published versionSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Plasma outflows from the edges of active regions have been suggested as a possible source of the slow solar wind. Spectroscopic measurements show that these outflows have an enhanced elemental composition, which is a distinct signature of the slow wind. Current spectroscopic observations, however, do not have sufficient spatial resolution to distinguish what structures are being measured or to determine the driver of the outflows. The High-resolution Coronal Imager (Hi-C) flew on a sounding rocket in May, 2018, and observed areas of active region outflow at the highest spatial resolution ever achieved (250 km). Here we use the Hi-C data to disentangle the outflow composition signatures observed with the Hinode satellite during the flight. We show that there are two components to the outflow emission: a substantial contribution from expanded plasma that appears to have been expelled from closed loops in the active region core, and a second contribution from dynamic activity in active region plage, with a composition signature that reflects solar photospheric abundances. The two competing drivers of the outflows may explain the variable composition of the slow solar wind.
- [27] arXiv:2004.07465 [pdf, ps, other]
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Title: X-ray emission from the mixed-morphology supernova remnant HB 9Comments: Accepted for publication in PASJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We present the results of a spectral analysis of the central region of the mixed-morphology supernova remnant HB 9. A prior Ginga observation of this source detected a hard X-ray component above 4 keV and the origin of this particular X-ray component is still unknown. Our results demonstrate that the extracted X-ray spectra are best represented by a model consisting of a collisional ionization equilibrium plasma with a temperature of ~0.1-0.2 keV (interstellar matter component) and an ionizing plasma with a temperature of ~0.6-0.7 keV and an ionization timescale of >1 x 10^{11} cm^{-3} s (ejecta component). No significant X-ray emission was found in the central region above 4 keV. The recombining plasma model reported by a previous work does not explain our spectra.
- [28] arXiv:2004.07468 [pdf, ps, other]
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Title: Relativistic, finite temperature multifluid hydrodynamics in a neutron star from a variational principleComments: 25 pages, submitted to PRD. Comments welcomeSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We develop a relativistic multifluid dynamics appropriate for describing neutron star cores at finite temperatures based on Carter's convective variational procedure. The model includes seven fluids, accounting for both normal and superfluid/superconducting neutrons and protons, leptons (electrons and muons) and entropy. The formulation is compared to the non-variational relativistic multifluid hydrodynamics of Gusakov and collaborators and shown to be equivalent. Vortex lines and flux tubes, mutual friction, vortex pinning, heat conduction and viscosity are incorporated into the model in steps after the basic hydrodynamics is described. The multifluid system is then considered at the mesoscopic scale where the currents around individual vortex lines and flux tubes are important, and this mesoscopic theory is averaged to determine the detailed vortex line/flux tube contributions to the macroscopic "effective" theory. This matching procedure is largely successful, though obtaining full agreement between the averaged mesoscopic and macroscopic effective theory requires discarding subdominant terms. The matching procedure allow us to show that the magnetic $H$-field inside a neutron star differs from that given in previous astrophysical works, but is in agreement with condensed matter physics literature.
- [29] arXiv:2004.07481 [pdf, other]
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Title: A new and simple prescription for planet orbital migration and eccentricity damping by planet-disc interactions based on dynamical frictionComments: 10 pages, 1 figure, accepted for publication in MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
During planet formation gravitational interaction between a planetary embryo and the protoplanetary gas disc causes orbital migration of the planetary embryo, which plays an important role in shaping the final planetary system. While migration sometimes occurs in the supersonic regime, wherein the relative velocity between the planetary embryo and the gas is higher than the sound speed, migration prescriptions proposed thus far describing the planet-disc interaction force and the timescales of orbital change in the supersonic regime are inconsistent with one another. Here we discuss the details of existing prescriptions in the literature and derive a new simple and intuitive formulation for planet-disc interactions based on dynamical friction that can be applied in both supersonic and subsonic cases. While the existing prescriptions assume particular disc models, ours include the explicit dependence on the disc parameters; hence it can be applied to discs with any radial surface density and temperature dependence (except for the local variations with radial scales less than the disc scale height). Our prescription will reduce the uncertainty originating from different literature formulations of planet migration and will be an important tool to study planet accretion processes, especially when studying the formation of close-in low-mass planets that are commonly found in exoplanetary systems.
- [30] arXiv:2004.07488 [pdf, other]
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Title: A small-scale filament eruption inducing Moreton Wave, EUV Wave and Coronal Mass EjectionComments: 18 pages, 12 figures, 2 tables; Accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
With the launch of SDO, many EUV waves were observed during solar eruptions. However, the joint observations of Moreton and EUV waves are still relatively rare. We present an event that a small-scale filament eruption simultaneously results in a Moreton wave, an EUV wave and a Coronal Mass Ejection in active region NOAA 12740. Firstly, we find that some dark elongate lanes or filamentary structures in the photosphere existed under the small-scale filament and drifted downward, which manifests that the small-scale filament was emerging and lifting from subsurface. Secondly, combining the simultaneous observations in different Extreme UltraViolet (EUV) and H$\alpha$ passbands, we study the kinematic characteristics of the Moreton and EUV waves. The comparable propagating velocities and the similar morphology of Moreton and different passbands EUV wavefronts were obtained. We deduce that Moreton and different passbands EUV waves were the perturbations in different temperature-associated layers induced by the coronal magneto-hydrodynamic shock wave. We also find the refracted, reflected and diffracted phenomena during the propagation of the EUV wave. By using power-law fittings, the kinematic characteristics of unaffected, refracted and diffracted waves were obtained. The extrapolation field derived by the potential field source surface (PFSS) model manifests that the existence of an interface of different magnetic system (magnetic separatrix) result in refraction, reflection and deviation of the EUV wave.
- [31] arXiv:2004.07491 [pdf, ps, other]
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Title: Protostellar accretion and the cosmological lithium problemAuthors: S. Cassisi (INAF-Astr. Obs. of Abruzzo, Italy), M. Salaris (ARI, Liverpool J. Moores Univ., UK), S. Degl'Innocenti (Physics Dept. Univ. of Pisa, Italy), P.G. Prada Moroni (Physics Dept. Univ. of Pisa, Italy), E. Tognelli (Physics Dept. Univ. of Pisa, Italy)Comments: 4 pages, 5 figures. Proceedings of the conference "Lithium in the Universe: to Be or not to Be", 18-22 November 2019, Rome (Italy)Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
The cosmological lithium problem, i.e. the discrepancy between the lithium abundance predicted by the Big Bang Nucleosynthesis and the one observed for the stars of the "Spite plateau", is one of the long standing problems of modern astrophysics. A possible astrophysical solution involves lithium burning due to protostellar mass accretion on Spite plateau stars. In present work, for the first time, we investigate with accurate evolutionary computations the impact of accretion on the lithium evolution in the metal-poor regime, that relevant for stars in the Spite plateau.
- [32] arXiv:2004.07504 [pdf, other]
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Title: Localizing Transformations of the Galaxy-Galaxy Lensing ObservableComments: 6 pages, 3 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Modern cosmological analyses of galaxy-galaxy lensing face a theoretical systematic effect arising from the non-locality of the observed galaxy-galaxy lensing signal. Because the predicted tangential shear signal at a given separation depends on the physical modeling on all scales internal to that separation, systematic uncertainties in the modeling of non-linear small scales are propagated outwards to larger scales. Even in the absence of other limiting factors, this systematic effect alone can necessitate conservative small-scale cuts, resulting in significant losses of information in the tangential shear data vector. We construct a simple linear transformation of the observable that removes this non-locality, enabling more aggressive small-scale cuts for a given theoretical model. Our modified galaxy-galaxy lensing observable makes it possible to include observations on significantly smaller scales than those under the standard approach in cosmological analyses. More importantly, it ensures that the cosmological signal contained within the observable is exclusively drawn from well-understood physical scales.
- [33] arXiv:2004.07523 [pdf, other]
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Title: The dependence of episodic accretion on eccentricity during the formation of binary starsComments: Submitted to A&A. 14 pages, 8 figures (plus 3 in appendix)Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
Aims: Investigate how the strength of episodic accretion bursts depends on eccentricity. Methods: We investigate the binary trigger hypothesis in longer-period (>20yr) binaries by carrying out three-dimensional magnetohydrodynamical (MHD) simulations of the formation of low-mass binary stars down to final separations of ~10AU, including the effects of gas turbulence and magnetic fields. We run two simulations with an initial turbulent gas core of one solar mass each and two different initial turbulent Mach numbers, M = 0.1 and 0.2, for 6500yr after protostar formation. Results: We observe bursts of accretion at periastron during the early stages when the eccentricity of the binary system is still high. We find that this correlation between bursts of accretion and passing periastron breaks down at later stages, because of the gradual circularisation of the orbits. For eccentricities greater than e=0.2, we observe episodic accretion triggered near periastron. However, we do not find any strong correlation between the strength (the ratio of the burst accretion ratio to the quiescent accretion rate) of episodic accretion and eccentricity. We determine that accretion events are likely triggered by torques between the rotation of the circumstellar disc and the approaching binary stars. We compare our results with observational data of episodic accretion in short-period binaries and find good agreement between our simulations and the observations. Conclusions: We conclude that episodic accretion is a universal mechanism operating in eccentric young binary-star systems, independent of separation, and should be observable in long-period binaries as well as in short-period binaries, but that the strength will depend on the torques, and hence the separation at periastron.
- [34] arXiv:2004.07535 [pdf, other]
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Title: Simulations of black hole accretion torus in various magnetic field configurationsComments: submitted to Proceedings of RAGtime 20-22, 11 pages, 6 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Using axisymetric general relativistic magnetohydrodynamics simulations we study evolution of accretion torus around black hole endowed with different initial magnetic field configurations. Due to accretion of material onto black hole, parabolic magnetic field will develop in accretion torus funnel around vertical axis, for any initial magnetic field configuration.
- [35] arXiv:2004.07556 [pdf, other]
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Title: The closest extremely low-mass white dwarf to the SunAuthors: Adela Kawka, Jeffrey D. Simpson, Stephane Vennes, Michael S. Bessell, Gary S. Da Costa, Anna F. Marino, Simon J. MurphyComments: Accepted for publication in MNRAS LettersSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present the orbit and properties of 2MASS J050051.85-093054.9, establishing it as the closest (d ~ 71 pc) extremely low mass white dwarf to the Sun. We find that this star is hydrogen-rich with Teff ~ 10 500 K, log g ~ 5.9, and, following evolutionary models, has a mass of ~ 0.17 solar masses. Independent analysis of radial velocity and TESS photometric time series reveals an orbital period of ~ 9.5 h. Its high velocity amplitude (K ~ 144 km/s) produces a measurable Doppler beaming effect in the TESS light curve with an amplitude of 1 mmag. The unseen companion is most likely a faint white dwarf. J0500-0930 belongs to a class of post-common envelope systems that will most likely merge through unstable mass transfer and in specific circumstances lead to Type Ia supernova explosions.
- [36] arXiv:2004.07586 [pdf, ps, other]
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Title: FOREST unbiased Galactic plane imaging survey with the Nobeyama 45 m telescope (FUGIN). VII. molecular fraction of HI cloudsAuthors: Hiroyuki Nakanishi, Shinji Fujita, Kengo Tachihara, Natsuko Izumi, Mitsuhiro Matsuo, Tomofumi Umemoto, Yumiko Oasa, Tsuyoshi InoueComments: 13 pages, 11 figures and 2 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA)
In this study, we analyze molecular gas formation in neutral atomic hydrogen (HI) clouds using the latest CO data obtained from the four-beam receiver system on a 45-m telescope (FOREST) unbiased Galactic plane imaging survey with the Nobeyama 45-m telescope (FUGIN) and HI data taken from the Very Large Array (VLA) Galactic plane survey (VGPS). We applied a dendrogram algorithm to the HI data cube to identify HI clouds, and we calculated the HI mass and molecular gas mass by summing the CO line intensity within each HI cloud. On the basis of the results, we created a catalog of 5,737 identified HI clouds with local standard of rest (LSR) velocity of $V_{\rm LSR}\le -20$ km s$^{-1}$ in Galactic longitude and latitude ranges of $20^\circ \le l \le 50^\circ$ and $-1^\circ \le b \le 1^\circ$, respectively. We found that most of the HI clouds are distributed within a Galactocentric distance of 16 kpc, most of which are in the Cold Neutral Medium (CNM) phase. In addition, we determined that the high-mass end of the mass HI function is well fitted with the power-law function with an index of 2.3. Although two sequences of self-gravitating and diffuse clouds are expected to appear in the M$_{\rm tot}$-M$_{{\rm H}_2}$ diagram according to previous works based on a plane-parallel model, the observational data show only a single sequence with large scattering within these two sequences. This implies that most of the clouds are mixtures of these two types of clouds. Moreover, we suggest the following scenario of molecular gas formation: An HI-dominant cloud evolved with increasing H$_2$ mass along a path of $M_{{\rm H}_2} \propto M_{\rm tot}^2$ by collecting diffuse gas before reaching and moving along the curves of the two sequences.
- [37] arXiv:2004.07589 [pdf, other]
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Title: Simultaneous TESS and NGTS Transit Observations of WASP-166bAuthors: Edward M. Bryant, Daniel Bayliss, James McCormac, Peter J. Wheatley, Jack S. Acton, David R. Anderson, David J. Armstrong, François Bouchy, Claudia Belardi, Matthew R. Burleigh, Rosie H. Tilbrook, Sarah L. Casewell, Benjamin F. Cooke, Samuel Gill, Michael R. Goad, James S. Jenkins, Monika Lendl, Don Pollacco, Didier Queloz, Liam Raynard, Alexis M. S. Smith, Jose I. Vines, Richard G. West, Stephane UdryComments: 10 pages, 8 figures. Accepted for publication in MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We observed a transit of WASP-166 b using nine NGTS telescopes simultaneously with TESS observations of the same transit. We achieved a photometric precision of 152 ppm per 30 minutes with the nine NGTS telescopes combined, matching the precision reached by TESS for the transit event around this bright (T=8.87) star. The individual NGTS light curve noise is found to be dominated by scintillation noise and appears free from any time-correlated noise or any correlation between telescope systems. We fit the NGTS data for $T_C$ and $R_p/R_*$. We find $T_C$ to be consistent to within 0.25$\sigma$ of the result from the TESS data, and the difference between the TESS and NGTS measured $R_p/R_*$ values is 0.9$\sigma$. This experiment shows that multi-telescope NGTS photometry can match the precision of TESS for bright stars, and will be a valuable tool in refining the radii and ephemerides for bright TESS candidates and planets. The transit timing achieved will also enable NGTS to measure significant transit timing variations in multi-planet systems.
- [38] arXiv:2004.07591 [pdf, other]
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Title: Transient brightenings in the quiet Sun detected by ALMA at 3 mmComments: A&A, accepted for publication (abbreviated abstract)Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Using ALMA observations, we performed the first systematic survey for transient brightenings (i.e. weak, small-scale episodes of energy release) in the quiet solar chromosphere at 3 mm. Our dataset included images of six 87'' x 87'' regions of the quiet Sun obtained with angular resolution of a few arcsec at a cadence of 2 s. The transient brightenings were detected as weak enhancements above the average intensity after we removed the effect of the p-mode oscillations. A similar analysis, over the same regions, was performed for simultaneous 304 and 1600 \AA\ data obtained with the Atmospheric Imaging Assembly. We detected 184 3 mm transient brightening events with brightness temperatures from 70 K to more than 500 K above backgrounds of $\sim 7200-7450$ K. Their mean duration and maximum area were 51.1 s and 12.3 Mm$^2$, respectively, with a weak preference of appearing at network boundaries rather than in cell interiors. Both parameters exhibited power-law behavior with indices of 2.35 and 2.71, respectively. Only a small fraction of ALMA events had either 304 or 1600 \AA\ counterparts but the properties of these events were not significantly different from those of the general population except that they lacked their low-end energy values. The total thermal energies of the ALMA transient brightenings were between $1.5 \times 10^{24}$ and $9.9 \times 10^{25}$ erg and their frequency distribution versus energy was a power law with an index of 1.67. We found that the power per unit area provided by the ALMA events could account for only 1\% of the chromospheric radiative losses (10\% of the coronal ones). Therefore, their energy budget falls short of meeting the requirements for the heating of the upper layers of the solar atmosphere and this conclusion does not change even if we use the least restrictive criteria possible for the detection of transient brightenings.
- [39] arXiv:2004.07595 [pdf, other]
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Title: Characterization of a dual-beam, dual-camera optical imaging polarimeterAuthors: Manisha Shrestha, Iain A. Steele, Andrez S. Piascik, Helen Jermak, Robert J. Smith, Chris M. CopperwheatComments: 12 pages, 11 figures, Accepted for publication in MNRASSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Polarization plays an important role in various time-domain astrophysics to understand the magnetic fields, geometry, and environments of spatially unresolved variable sources. In this paper we present the results of laboratory and on-sky testing of a novel dual-beam, dual-camera optical imaging polarimeter (MOPTOP) exploiting high sensitivity, low-noise CMOS technology and designed to monitor variable and transient sources with low systematic errors and high sensitivity. We present a data reduction algorithm that corrects for sensitivity variations between the cameras on a source-by-source basis. Using our data reduction algorithm, we show that our dual-beam, dual-camera technique delivers the benefits of low and stable instrumental polarization ($<0.05$\% for lab data and $<0.25$\% for on sky data) and high throughput while avoiding the additional sky brightness and image overlap problems associated with dual-beam, single-camera polarimeters.
- [40] arXiv:2004.07599 [pdf, other]
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Title: Low Threshold Acquisition controller for Skipper CCDsAuthors: Gustavo Cancelo, Claudio Chavez, Fernando Chierchie, Juan Estrada, Guillermo Fernandez Moroni, Eduardo Emilio Paolini, Miguel Sofo Haro, Angel Soto, Leandro Stefanazzi, Javier Tiffenberg, Ken Treptow, Neal Wilcer, Ted ZmudaSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Instrumentation and Detectors (physics.ins-det); Quantum Physics (quant-ph)
The development of the Skipper Charge Coupled Devices (Skipper-CCDs) has been a major technological breakthrough for sensing very weak ionizing particles. The sensor allows to reach the ultimate sensitivity of silicon material as a charge signal sensor by unambiguous determination of the charge signal collected by each cell or pixel, even for single electron-hole pair ionization. Extensive use of the technology was limited by the lack of specific equipment to operate the sensor at the ultimate performance. In this work a simple, single-board Skipper-CCD controller is presented, aimed for the operation of the detector in high sensitivity scientific applications. The article describes the main components and functionality of the Low Threshold Acquisition (LTA) together with experimental results when connected to a Skipper-CCD sensor. Measurements show unprecedented deep sub-electron noise of 0.039 e$^-_{rms}$/pix for 5000 pixel measurements.
- [41] arXiv:2004.07604 [pdf, other]
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Title: The XMM deep survey in the CDFS XI. X-ray properties of 185 bright sourcesAuthors: K. Iwasawa, A. Comastri, C. Vignali, R. Gilli, G. Lanzuisi, W .N. Brandt, P. Tozzi, M. Brusa, F. J. Carrera, P. Ranalli, V. Mainieri, I. Georgantopoulos, S. Puccetti, M. PaolilloComments: Accepted for publication in Astronomy & Astrophysics. Table 1 with some extra information (Chandra source IDs etc.) will be available on CDS once the paper has been publishedSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
We present X-ray spectra of 185 bright sources detected in the XMM-Newton deep survey of the Chandra Deep Field South, combining the three EPIC cameras. The 2-10 keV flux limit of the sample is 2e-15 erg/s/cm2. The sources are distributed over a redshift range of z=0.1-3.8. Eleven new X-ray redshift measurements are included. A spectral analysis was performed using a simple model to obtain absorbing column densities, rest-frame 2-10 keV luminosities and Fe K line properties of 180 sources at z>0.4. Obscured AGN are found to be more abundant toward higher redshifts. Using the XMM-Newton data alone, seven Compton-thick AGN candidates are identified, which makes the Compton-thick AGN fraction to be ~4%. An exploratory spectral inspection method with two rest-frame X-ray colours and an Fe line strength indicator is introduced and tested against the results from spectral fitting. This method works reasonably well to characterise a spectral shape and can be useful for a pre-selection of Compton-thick AGN candidates. We found six objects exhibiting broad Fe K lines out of 21 unobscured AGN of best data quality, implying a detection rate of ~30%. Five redshift spikes, each of which has more than six sources, are identified in the redshift distribution of the X-ray sources. Contrary to the overall trend, the sources at the two higher-redshift spikes at z=1.61 and z=2.57 have puzzlingly low obscuration.
- [42] arXiv:2004.07621 [pdf, other]
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Title: Modeling the spectrum and composition of ultrahigh-energy cosmic rays with two populations of extragalactic sourcesComments: 10 pages, 3 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We fit the ultrahigh-energy cosmic-ray (UHECR, $E\gtrsim0.1$ EeV) spectrum and composition data from the Pierre Auger Observatory at energies $E\gtrsim5\cdot10^{18}$ eV, i.e., beyond the ankle using two populations of astrophysical sources. One population, accelerating dominantly protons ($^1$H), extends up to the highest observed energies with maximum energy close to the GZK cutoff and injection spectral index near the Fermi acceleration model; while another population accelerates light-to-heavy nuclei ($^4$He, $^{14}$N, $^{28}$Si, $^{56}$Fe) with a relatively low rigidity cutoff and hard injection spectrum. A single extragalactic homogeneous source population with a mixed composition ($^1$H, $^4$He, $^{14}$N, $^{28}$Si, $^{56}$Fe) at injection leads to zero $^1$H abundance fraction, while fitting the spectrum at energies $\gtrsim 5\cdot10^{18}$ eV. With our choice of exponential cutoff power-law injection spectrum and \textsc{sybill2.3c} hadronic interaction model, we investigate the effects on composition predictions and other UHECR source parameters, as we go from a single-population to two-population model. For the latter, a non-zero $^1$H abundance is found to be inevitable at the highest energies, and a significant improvement in the combined fit is noted on addition of a pure-proton spectrum. We vary the proton injection index to find the best-fit parameter values of the two-population model, and constrain the maximum allowed proton fraction at the highest-energy bin within 3.5$\sigma$ statistical significance. We compute expected cosmogenic neutrino flux in such a hybrid source population scenario and discuss possibilities to detect these neutrinos by upcoming detectors to shed light on the sources of UHECRs.
- [43] arXiv:2004.07627 [pdf, other]
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Title: Statistical relations between stellar spectral and luminosity classes and stellar effective temperature and surface gravityComments: accepted by Research in Astronomy and AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We have determined new statistical relations to estimate the fundamental atmospheric parameters of effective temperature and surface gravity, using MK spectral classification, and vice versa. The relations were constructed based on the published calibration tables (for main sequence stars) and observational data from stellar spectral atlases (for giants and supergiants). These new relations were applied to field giants with known atmospheric parameters, and the results of the comparison of our estimations with available spectral classification had been quite satisfactory.
- [44] arXiv:2004.07647 [pdf, other]
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Title: Unveiling the power spectra of $δ$ Scuti stars with TESS. The temperature, gravity, and frequency scaling relationAuthors: S. Barceló Forteza, A. Moya, D. Barrado, E. Solano, S. Martín-Ruiz, J. C. Suárez, A. García HernándezComments: 12 pages, 13 figures, accepted in Astronomy & AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Thanks to high-precision photometric data legacy from space telescopes like CoRoT and Kepler, the scientific community could detect and characterize the power spectra of hundreds of thousands of stars. Using the scaling relations, it is possible to estimate masses and radii for solar-type pulsators. However, these stars are not the only kind of stellar objects that follow these rules: $\delta$ Scuti stars seem to be characterized with seismic indexes such as the large separation ($\Delta\nu$). Thanks to long-duration high-cadence TESS light curves, we analysed more than two thousand of this kind of classical pulsators. In that way, we propose the frequency at maximum power ($\nu_{\rm max}$) as a proper seismic index since it is directly related with the intrinsic temperature, mass and radius of the star. This parameter seems not to be affected by rotation, inclination, extinction or resonances, with the exception of the evolution of the stellar parameters. Furthermore, we can constrain rotation and inclination using the departure of temperature produced by the gravity-darkening effect. This is especially feasible for fast rotators as most of $\delta$ Scuti stars seem to be.
- [45] arXiv:2004.07654 [pdf, other]
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Title: Numerical simulations of shear-induced consecutive coronal mass ejectionsAuthors: D.-C. Talpeanu (1 and 2), E. Chané (1), S. Poedts (1 and 3), E. D'Huys (2), M. Mierla (2 and 4), I. Roussev (5 and 1), S. Hosteaux (1) ((1) Centre for mathematical Plasma Astrophysics (CmPA), Department of Mathematics, KU Leuven, Leuven, Belgium, (2) SIDC - Royal Observatory of Belgium (ROB), Brussels, Belgium, (3) Institute of Physics, University of Maria Curie-Skłodowska, Lublin, Poland, (4) Institute of Geodynamics of the Romanian Academy, Bucharest, Romania, (5) Division of Atmospheric and Geospace Sciences - Directorate of Geosciences - National Science Foundation, Arlington, Virginia, USA)Comments: 11 pages, 12 figures, to be published in "Astronomy & Astrophysics", and the associated movies will also be available on the journal's websiteSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Methods: Stealth CMEs represent a particular class of solar eruptions that are clearly distinguished in coronagraph observations, but they don't have a clear source signature. A particular type of stealth CMEs occurs in the trailing current sheet of a previous ejection, therefore, we used the 2.5D MHD package of the code MPI-AMRVAC to numerically simulate consecutive CMEs by imposing shearing motions onto the inner boundary. The initial magnetic configuration consists of a triple arcade structure embedded into a bimodal solar wind, and the sheared polarity inversion line is found in the southern loop system. The mesh was continuously adapted through a refinement method that applies to current carrying structures. We then compared the obtained eruptions with the observed directions of propagation of an initial multiple coronal mass ejection (MCME) event that occurred in September 2009. We further analysed the simulated ejections by tracking the centre of their flux ropes in latitude and their total speed. Radial Poynting flux computation was employed as well to follow the evolution of electromagnetic energy introduced into the system.
Results: Changes within 1\% in the shearing speed result in three different scenarios for the second CME, although the preceding eruption seems insusceptible to such small variations. Depending on the applied shearing speed, we thus obtain a failed eruption, a stealth, or a CME driven by the imposed shear, as the second ejection. The dynamics of all eruptions are compared with the observed directions of propagation of an MCME event and a good correlation is achieved. The Poynting flux analysis reveals the temporal variation of the important steps of eruptions. For the first time, a stealth CME is simulated in the aftermath of a first eruption, through changes in the applied shearing speed. - [46] arXiv:2004.07669 [pdf, other]
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Title: Inferring the origins of the pulsed gamma-ray emission from the Crab pulsar with 10-year Fermi LAT dataAuthors: Paul K. H. YeungComments: Submitted to A&A on 14.04.2020Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Context: The Crab pulsar is a bright $\gamma$-ray source detected at photon energies up to $\sim$1 TeV. Its phase-averaged and phase-resolved $\gamma$-ray spectra both exhibit (sub-)exponential cutoffs while those above 10 GeV apparently follow simple power-laws. Aims: We re-visit the $\gamma$-ray properties of the Crab pulsar with 10-year \emph{Fermi} Large Area Telescope (LAT) data in the range of 60 MeV--500 GeV. With the phase-resolved spectra, we investigate the origins and mechanisms responsible for the emissions. Methods: The phaseograms are reconstructed for different energy bands and further analysed using a wavelet decomposition. The phase-resolved energy spectra are combined with the observations of ground-based instruments like MAGIC and VERITAS to achieve a larger energy converage. We fit power-law models to the overlapping energy spectra from 10 GeV to $\sim$1 TeV. We include in the fit a relative cross-calibration of energy scales between air-shower based gamma-ray telescopes with the orbital pair-production telescope of the Fermi mission. Results: We confirm the energy-dependence of the $\gamma$-ray pulse shape, and equivalently, the phase-dependence of the spectral shape for the Crab pulsar. A relatively sharp exponential cutoff at a relatively high energy of $\sim$8 GeV is observed for the bridge-phase emission. The $E>$10 GeV spectrum observed for the second pulse peak is harder than those for other phases. Conclusions: In view of the diversity of phase-resolved spectral shapes of the Crab pulsar, we tentatively propose a multi-origin scenario where the polar-cap, outer-gap and relativistic-wind regions are involved.
- [47] arXiv:2004.07670 [pdf, other]
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Title: The BAHAMAS project: Effects of dynamical dark energy on large-scale structureAuthors: Simon Pfeifer, Ian G. McCarthy, Sam G. Stafford, Shaun T. Brown, Andreea S. Font, Juliana Kwan, Jaime Salcido, Joop SchayeComments: 18 pages, 15 figures, submitted to MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
In this work we consider the impact of spatially-uniform but time-varying dark energy (or `dynamical dark energy', DDE) on large-scale structure in a spatially flat universe, using large cosmological hydrodynamical simulations that form part of the BAHAMAS project. As DDE changes the expansion history of the universe, it impacts the growth of structure. We explore variations in DDE that are constrained to be consistent with the cosmic microwave background. We find that DDE can affect the clustering of matter and haloes at the ~10% level (suppressing it for so-called `freezing' models, while enhancing it for `thawing' models), which should be distinguishable with upcoming large-scale structure surveys. DDE cosmologies can also enhance or suppress the halo mass function (with respect to LCDM) over a wide range of halo masses. The internal properties of haloes are minimally affected by changes in DDE, however. Finally, we show that the impact of baryons and associated feedback processes is largely independent of the change in cosmology and that these processes can be modelled separately to typically better than a few percent accuracy
- [48] arXiv:2004.07687 [pdf]
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Title: Physical Characteristics of Umbral Dots Derived from a High Resolution ObservationComments: accepted for publication in Solar PhysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The aim of this study is revisit the physical parameters of umbral dots (UDs) with the latest high resolution observations and contribute to the scientific understanding of their formation and evolution. In this study, we applied a particle tracking algorithm for detecting UDs in NOAA AR12384 observed on June 14, 2015 by the Goode Solar Telescope (GST). We analyzed average position distributions, location dependencies, and general properties of detected total 2892 UDs separately during their life time and the periodic behavior of only selected 10 long living UDs. We found; i) brightest, largest, fastest and most elliptic UDs tend to be located at the umbra-penumbra boundary while their lifetime does not display any meaningful location dependency, ii) average dynamic velocity of all detected UDs is about twice (0.76 km/s) of the previously reported average values, iii) obtained trajectories from the longest living 354 UDs show that they have generally inward motion, iv) chosen 10 long living UDs generally have similar periodic behavior showing 8.5-32, 3.5-4.1, 1.5-1.9, and 1.1-1.3 minutes periodicities, v) generally, detected UDs have an elliptical shape with the averaged eccentricity of 0.29, with a 0.11 standard deviation, vi) larger UDs tend to be more elliptic and more dynamic.
- [49] arXiv:2004.07709 [pdf, other]
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Title: Late-time decaying dark matter: constraints and implications for the $H_0$-tensionComments: 9 pages, 5 figures; comments are welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
We constrain and update the bounds on the life-time of a decaying dark matter model with a warm massive daughter particle using the most recent low-redshift probes. We use Supernovae Type-Ia, Baryon Acoustic Oscillations and the time delay measurements of gravitationally lensed quasars. These data sets are complemented by the early universe priors taken from the Cosmic Microwave background. For the maximum allowed fraction of the relativistic daughter particle, the updated bounds on the life-time are found to be $\tau > 9\, \rm{Gyr}$ and $\tau >11\,\rm{Gyr}$ at $95\%$ C.L., for the two-body and many-body decay scenarios, respectively. We also comment on the recent proposal that the current two-body decaying dark matter model can provide resolution for the $H_0$-tension, by contrasting against the standard $\Lambda$CDM model. We infer that the current dark matter decaying scenario is unlikely to alleviate the $H_0$-tension. We find that the decaying dark matter is able to reduce the trend of the decreasing $H_0$ values with increasing lens redshifts observed in the strong lensing dataset.
- [50] arXiv:2004.07727 [pdf, other]
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Title: Accretion Disc Winds in Tidal Disruption Events: Ultraviolet Spectral Lines as Orientation IndicatorsAuthors: Edward J. Parkinson, Christian Knigge, Knox S. Long, James H. Matthews, Nick Higginbottom, Stuart A. Sim, Henrietta A. HewittComments: 16 pages, 9 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Some tidal disruption events (TDEs) exhibit blueshifted broad absorption lines (BALs) in their rest-frame ultraviolet (UV) spectra, while others display broad emission lines (BELs). Similar phenomenology is observed in quasars and accreting white dwarfs, where it can be interpreted as an orientation effect associated with line formation in an accretion disc wind.We propose and explore a similar unification scheme for TDEs. We present synthetic UV spectra for disc and wind-hosting TDEs, produced by a state-of-the-art Monte Carlo ionization and radiative transfer code. Our models cover a wide range of disc wind geometries and kinematics. Such winds naturally reproduce both BALs and BELs. In general, sight lines looking into the wind cone preferentially produce BALs, while other orientations preferentially produce BELs. We also study the effect of wind clumping and CNO-processed abundances on the observed spectra. Clumpy winds tend to produce stronger UV emission and absorption lines, because clumping increases both the emission measure and the abundances of the relevant ionic species, the latter by reducing the ionization state of the outflow. The main effect of adopting CNO-processed abundances is a weakening of C~{\sc iv}~1550~\AA~ and an enhancement of N \textsc{v}~1240~\AA~ in the spectra. We conclude that line formation in an accretion disc wind is a promising mechanism for explaining the diverse UV spectra of TDEs. If this is correct, the relative number of BAL and BEL TDEs can be used to estimate the covering factor of the outflow. The models in this work are publicly available online and upon request.
- [51] arXiv:2004.07744 [pdf, other]
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Title: Direct Astrophysical Tests of Chiral Effective Field Theory at Supranuclear DensitiesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
Recent observations of neutron stars with gravitational waves and X-ray timing provide unprecedented access to the equation of state (EoS) of cold dense matter at densities difficult to realize in terrestrial experiments. At the same time, predictions for the EoS with reliable uncertainty estimates from chiral effective field theory ($\chi$EFT) bound our theoretical ignorance. In this work, we analyze astrophysical data using a nonparametric representation of the neutron star EoS conditioned on $\chi$EFT to directly constrain the underlying physical properties of the compact objects. We discuss how the data alone constrain the EoS at high densities when we condition on $\chi$EFT at low densities. We also demonstrate how to exploit astrophysical data to directly test the predictions of $\chi$EFT for the EoS up to twice nuclear saturation density, and estimate the density at which these predictions might break down. We find that the existence of massive pulsars, gravitational waves from GW170817, and NICER observations of PSR J0030+0451 favor $\chi$EFT predictions for the EoS up to nuclear saturation density over a more agnostic analysis by a factor of 7 for the quantum Monte Carlo (QMC) calculations used in this work. While $\chi$EFT predictions using QMC are fully consistent with gravitational-wave data up to twice nuclear saturation, NICER observations suggest that the EoS stiffens relative to these predictions at nuclear saturation density. Additionally, we marginalize over the uncertainty in the density at which $\chi$EFT begins to break down, constraining the radius of a $1.4\,M_\odot$ neutron star to $R_{1.4} = 11.40^{+1.38}_{-1.04}$ ($12.54^{+0.71}_{-0.63}$) km and the pressure at twice nuclear saturation density to $p(2n_\mathrm{sat}) = 14.2^{+18.1}_{-8.4}$ ($28.7^{+15.3}_{-15.0}$) $\mathrm{MeV}/\mathrm{fm}^3$ with massive pulsar and gravitational-wave (and NICER) data.
- [52] arXiv:2004.07768 [pdf, ps, other]
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Title: HST/FGS Trigonometric Parallaxes of M-dwarf Eclipsing BinariesAuthors: Gerard T. van Belle, Gail H. Schaefer, Kaspar von Braun, Edmund P. Nelan, Zachary Hartman, Tabetha S. Boyajian, Mercedes Lopez-Morales, David R. CiardiComments: 28 pages, 12 figures, accepted for publication in PASPSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Hubble Space Telescope (HST) Fine Guidance Sensor (FGS) trigonometric parallax observations were obtained to directly determine distances to five nearby M-dwarf / M-dwarf eclipsing binary systems. These systems are intrinsically interesting as benchmark systems for establishing basic physical parameters for low-mass stars, such as luminosity L, and radius R. HST/FGS distances are also one of the few direct checks on Gaia trigonometric parallaxes, given the comparable sensitivity in both magnitude limit and determination of parallactic angles. A spectral energy distribution (SED) fit of each system's blended flux output was carried out, allowing for estimation of the bolometric flux from the primary and secondary components of each system. From the stellar M, L, and R values, the low-mass star relationships between L and M, and R and M, are compared against idealized expectations for such stars. An examination on the inclusion of these close M-dwarf/M-dwarf pairs in higher-order common proper motion (CPM) pairs is analysed; each of the 5 systems has indications of being part of a CPM system. Unexpected distances on interesting objects found within the grid of parallactic reference stars are also presented, including a nearby M dwarf and a white dwarf.
- [53] arXiv:2004.07783 [pdf, other]
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Title: TOI-1338: TESS' First Transiting Circumbinary PlanetAuthors: Veselin B. Kostov, Jerome A. Orosz, Adina D. Feinstein, William F. Welsh, Wolf Cukier, Nader Haghighipour, Billy Quarles, David V. Martin, Benjamin T. Montet, Guillermo Torres, Amaury H.M.J. Triaud, Thomas Barclay, Patricia Boyd, Cesar Briceno, Andrew Collier Cameron, Alexandre C.M. Correia, Emily A. Gilbert, Samuel Gill, Michael Gillon, Jacob Haqq-Misra, Coel Hellier, Courtney Dressing, Daniel C. Fabrycky, Gabor Furesz, Jon Jenkins, Stephen R. Kane, Ravi Kopparapu, Vedad Kunovac Hodzic, David W. Latham, Nicholas Law, Alan M. Levine, Gongjie Li, Chris Lintott, Jack J. Lissauer, Andrew W. Mann, Tsevi Mazeh, Rosemary Mardling, Pierre F.L. Maxted, Nora Eisner, Francesco Pepe, Joshua Pepper, Don Pollacco, Samuel N. Quinn, Elisa V. Quintana, Jason F. Rowe, George Ricker, Mark E. Rose, Sara Seager, et al. (20 additional authors not shown)Comments: 35 pages, 21 figures, 6 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
We report the detection of the first circumbinary planet found by TESS. The target, a known eclipsing binary, was observed in sectors 1 through 12 at 30-minute cadence and in sectors 4 through 12 at two-minute cadence. It consists of two stars with masses of 1.1 MSun and 0.3 MSun on a slightly eccentric (0.16), 14.6-day orbit, producing prominent primary eclipses and shallow secondary eclipses. The planet has a radius of ~6.9 REarth and was observed to make three transits across the primary star of roughly equal depths (~0.2%) but different durations -- a common signature of transiting circumbinary planets. Its orbit is nearly circular (e ~ 0.09) with an orbital period of 95.2 days. The orbital planes of the binary and the planet are aligned to within ~1 degree. To obtain a complete solution for the system, we combined the TESS photometry with existing ground-based radial-velocity observations in a numerical photometric-dynamical model. The system demonstrates the discovery potential of TESS for circumbinary planets, and provides further understanding of the formation and evolution of planets orbiting close binary stars.
- [54] arXiv:2004.07789 [pdf, other]
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Title: The onset of instability in resonant chainsComments: Submitted to MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
There is evidence that most chains of mean motion resonances of type $k$:$k-1$ among exoplanets become unstable once the dissipative action from the gas is removed from the system, particularly for large $N$ (the number of planets) and $k$ (indicating how compact the chain is). We present a novel dynamical mechanism that can explain the origin of these instabilities and thus the dearth of resonant systems in the exoplanet sample. It relies on the emergence of secondary resonances between a fraction of the synodic frequency $2 \pi (1/P_1-1/P_2)$ and the libration frequencies in the mean motion resonance. These secondary resonances excite the amplitudes of libration of the mean motion resonances thus leading to an instability. We detail the emergence of these secondary resonances by carrying out an explicit perturbative scheme to second order in the planetary masses and isolating the harmonic terms that are associated with them. Focusing on the case of three planets in the 3:2 -- 3:2 mean motion resonance as an example, a simple but general analytical model of one of these resonances is obtained which describes the initial phase of the activation of one such secondary resonance. The dynamics of the excited system is also briefly described. This scheme shows how one can obtain analytical insight into the emergence of these resonances, and into the dynamics that they trigger. Finally, a generalisation of this dynamical mechanism is obtained for arbitrary $N$ and $k$. This leads to an explanation of previous numerical experiments on the stability of resonant chains, showing why the critical planetary mass allowed for stability decreases with increasing $N$ and $k$.
- [55] arXiv:2004.07792 [pdf, other]
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Title: Scalar Field Wave (Fuzzy) Dark Matter and the Formation of GalaxiesAuthors: Benjamin HammComments: 16 pages, 14 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
We investigate Scalar Field Wave Dark Matter in the context of galactic Dark Matter halos. In particular, we offer an analysis of the Baryonic Tully-Fisher Relation (BTFR). We detail a particular family of excited state solutions to the Einstein-Klein-Gordon equations, and use it to provide a novel theoretical model for producing the BTFR. We then solve this model computationally to simulate the BTFR. Interpreting the Dark Matter scalar field as an ultralight boson, this returns a conservative mass constraint of $m\geq 10^{-23}eV$. Assuming slightly stronger conditions suggests $m\geq 10^{-22}eV$ to be more compatible with the BTFR. We provide a discussion of Scalar Field Dark Matter rotation curves and the structure of Scalar Field Dark Matter halos. Compatibility with the BTFR requires the excited state solutions to obey particular boundary conditions; this may have implications for the behavior of Dark Matter halos and the formation of galaxies.
- [56] arXiv:2004.07811 [pdf, other]
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Title: Minimising the impact of scale-dependent galaxy bias on the joint cosmological analysis of large scale structuresAuthors: Marika Asgari, Indiarose Friswell, Mijin Yoon, Catherine Heymans, Andrej Dvornik, Benjamin Joachimi, Patrick Simon, Joe ZuntzComments: 14 pages, 12 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We present a mitigation strategy to reduce the impact of non-linear galaxy bias on the joint `$3 \times 2 $pt' cosmological analysis of weak lensing and galaxy surveys. The $\Psi$-statistics that we adopt are based on Complete Orthogonal Sets of E/B Integrals (COSEBIs). As such they are designed to minimise the contributions to the observable from the smallest physical scales where models are highly uncertain. We demonstrate that $\Psi$-statistics carry the same constraining power as the standard two-point galaxy clustering and galaxy-galaxy lensing statistics, but are significantly less sensitive to scale-dependent galaxy bias. Using two galaxy bias models, motivated by halo-model fits to data and simulations, we quantify the error in a standard $3 \times 2$pt analysis where constant galaxy bias is assumed. Even when adopting conservative angular scale cuts, that degrade the overall cosmological parameter constraints, we find of order $1 \sigma$ biases for Stage III surveys on the cosmological parameter $S_8 = \sigma_8(\Omega_{\rm m}/0.3)^{\alpha}$. This arises from a leakage of the smallest physical scales to all angular scales in the standard two-point correlation functions. In contrast, when analysing $\Psi$-statistics under the same approximation of constant galaxy bias, we show that the bias on the recovered value for $S_8$ can be decreased by a factor of $\sim 2$, with less conservative scale cuts. Given the challenges in determining accurate galaxy bias models in the highly non-linear regime, we argue that $3 \times 2$pt analyses should move towards new statistics that are less sensitive to the smallest physical scales.
Cross-lists for Fri, 17 Apr 20
- [57] arXiv:2002.02637 (cross-list from gr-qc) [pdf]
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Title: Ground Based Gravitational Wave Astronomy in the Asian RegionAuthors: Vaishali Adya, Matthew Bailes, Carl Blair, David Blair, Johannes Eichholz, Joris van Heijningen, Eric Howell, Li Ju, Paul Lasky, Andrew Melatos, David Ottaway, Chunnong ZhaoComments: Article for the AAPPS bulletinSubjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM)
The current gravitational wave detectors have identified a surprising population of heavy stellar mass black holes, and an even larger population of coalescing neutron stars. The first observations have led to many dramatic discoveries and the confirmation of general relativity in very strong gravitational fields. The future of gravitational wave astronomy looks bright, especially if additional detectors with greater sensitivity, broader bandwidth, and better global coverage can be implemented. The first discoveries add impetus to gravitational wave detectors designed to detect in the nHz, mHz and kHz frequency bands. This paper reviews the century-long struggle that led to the recent discoveries, and reports on designs and possibilities for future detectors. The benefits of future detectors in the Asian region are discussed, including analysis of the benefits of a detector located in Australia.
- [58] arXiv:2003.13430 (cross-list from cond-mat.mtrl-sci) [pdf, other]
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Title: Elastic properties of phases with nonspherical nuclei in dense matterComments: 9 pages, 6 figuresSubjects: Materials Science (cond-mat.mtrl-sci); High Energy Astrophysical Phenomena (astro-ph.HE); Other Condensed Matter (cond-mat.other); Nuclear Theory (nucl-th)
We consider the elastic constants of phases with nonspherical nuclei, so-called pasta phases, predicted to occur in the inner crust of a neutron star. First, we treat perfectly ordered phases and give numerical estimates for lasagna and spaghetti when the pasta elements are spatially uniform: the results are in order-of-magnitude agreement with the numerical simulations of Caplan, Schneider, and Horowitz, Phys. Rev. Lett. 121, 132701 (2018). We then turn to pasta phases without long-range order and calculate upper (Voigt) and lower (Reuss) bounds on the effective shear modulus and find that the lower bound is zero, but the upper bound is nonzero. To obtain better estimates, we then apply the self-consistent formalism and find that this predicts that the shear modulus of the phases without long-range order is zero if the pasta elements are spatially uniform. In numerical simulations, the pasta elements are found to be modulated spatially and we show that this modulation is crucial to obtaining a nonzero elastic moduli for pasta phases without long-range order. In the self-consistent formalism we find that, for lasagna, the effective shear modulus is linear in the elastic constants that do not vanish when the pasta elements are spatially uniform while, for spaghetti, it varies as the square root of these elastic constants. We also consider the behavior of the elastic constant associated with a homologous strain (hydrostatic compression) of the structure of the pasta phases without long-range order.
- [59] arXiv:2004.07255 (cross-list from physics.plasm-ph) [pdf, other]
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Title: Noise-Induced Magnetic Field Saturation in Kinetic SimulationsComments: 15 pages, 4 figures. Submitted to the Journal of Plasma Physics. Comments welcomeSubjects: Plasma Physics (physics.plasm-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Computational Physics (physics.comp-ph); Space Physics (physics.space-ph)
Monte Carlo methods are often employed to numerically integrate kinetic equations, such as the particle-in-cell method for the plasma kinetic equation, but these methods suffer from the introduction of counting noise to the solution. We report on a cautionary tale of counting noise modifying the nonlinear saturation of kinetic instabilities driven by unstable beams of plasma. We find a saturated magnetic field in under-resolved particle-in-cell simulations due to the sampling error in the current density. The noise-induced magnetic field is anomalous, as the magnetic field damps away in continuum kinetic and increased particle count particle-in-cell simulations. This modification of the saturated state has implications for a broad array of astrophysical phenomena beyond the simple plasma system considered here, and it stresses the care that must be taken when using particle methods for kinetic equations.
- [60] arXiv:2004.07269 (cross-list from gr-qc) [pdf, other]
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Title: Primordial Magnetogenesis in a Bouncing UniverseComments: 33 pages, 9 figures. Accepted for publication in Physical Review DSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
We investigate primordial magnetogenesis and the evolution of the electromagnetic field through a quantum bounce, in a model that starts in the far past from a contracting phase where only dust is present and the electromagnetic field is in the adiabatic quantum vacuum state. By including a coupling between curvature and electromagnetism of the form $RF_{\mu \nu}F^{\mu \nu}$, we find acceptable magnetic field seeds within the current observational constraints at 1 mega-parsec (Mpc), and that the magnetic power spectrum evolves as a power-law with spectral index $n_B=6$. It is also shown that the electromagnetic backreaction is not an issue in the model under scrutiny.
- [61] arXiv:2004.07410 (cross-list from physics.geo-ph) [pdf]
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Title: AstroSeis -- A 3D Boundary element modeling code for seismic wavefields in irregularly asteroids and bodiesComments: 27 pages, 10 figuresSubjects: Geophysics (physics.geo-ph); Earth and Planetary Astrophysics (astro-ph.EP); Computational Physics (physics.comp-ph)
We developed a 3-D elastic Boundary Element Method (BEM) computer code, called AstroSeis, to model seismic wavefields in a body with an arbitrary shape, such as an asteroid. Besides the AstroSeis can handle arbitrary surface topography, it can deal with a liquid core in an asteroid model. Both the solid and liquid domains are homogenous in our current code. For seismic sources, we can use single forces or moment tensors. The AstroSeis is implemented in the frequency domain and the frequency-dependent Q can be readily incorporated. The code is in MATLAB and it is straightforward to set up the model to run our code. The frequency-domain calculation is advantageous to study the long-term elastic response of a celestial body due to a cyclic force such as the tidal force with no numerical dispersion issue suffered by many other methods requiring volume meshing. Our AstroSeis has been benchmarked with other methods such as normal modes summation and the direct solution method (DSM). This open-source AstroSeis will be a useful tool to study the interior and surface processes of asteroids.
- [62] arXiv:2004.07515 (cross-list from gr-qc) [pdf, other]
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Title: Identifying and Addressing Nonstationary LISA NoiseAuthors: Matthew C. Edwards, Patricio Maturana-Russel, Renate Meyer, Jonathan Gair, Natalia Korsakova, Nelson ChristensenSubjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We anticipate noise from the Laser Interferometer Space Antenna (LISA) will exhibit nonstationarities throughout the duration of its mission due to factors such as antenna repointing, cyclostationarities from spacecraft motion, and glitches as highlighted by LISA Pathfinder. In this paper, we use a surrogate data approach to test the stationarity of a time series, with the goal of identifying noise nonstationarities in the future LISA mission. This will be necessary for determining how often the LISA noise power spectral density (PSD) will need to be updated for parameter estimation routines. We conduct a thorough simulation study illustrating the power/size of various versions of the hypothesis tests, and then apply these approaches to differential acceleration measurements from LISA Pathfinder. We also develop a data analysis strategy for addressing nonstationarities in the LISA PSD, where we update the noise PSD over time, while simultaneously conducting parameter estimation, with a focus on planned data gaps. We show that assuming stationarity when noise is nonstationary leads to systematic biases and large posterior variances in parameter estimates for galactic white dwarf binary gravitational wave signals.
- [63] arXiv:2004.07522 (cross-list from gr-qc) [pdf]
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Title: Verification of Einstein's formula for gravitational deflection of light using observations of Galactic microlensingComments: 12 pages, 1 figureSubjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA)
The potential of the gravitational microlensing inside our Galaxy for testing the Einstein formula for the gravitational light deflection is discussed. For this purpose, the lens mapping is modified by introducing parameter eps, which characterizes the deviation from this formula. An example of such deviation described by a simple power law is analyzed. We formed a sample of 100 microlensing light curves using the data of the Optical Gravitational Lensing Experiment (OGLE) for 2018. The resulting eps value does not contradict the General Relativity within 1 percent errors.
- [64] arXiv:2004.07695 (cross-list from physics.ins-det) [pdf]
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Title: Calibration of a Shower Lead-Scintillation Spectrometer by Cosmic RadiationAuthors: V.I. Alekseev, V.A. Baskov, V.A. Dronov, A.I. Lvov, A.V. Koltsov, Yu.F. Krechetov, V.V. Polyansky, S.S. SidorinComments: 8 pages, 5 figures, 5 referencesSubjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM)
The results of calibration by cosmic muons of a shower lead-scintillation spectrometer of the sandwich type designed to work in high-intensity photon and electron beams with an energy of 0.1 - 1.0 GeV are presented. It was found that the relative energy resolution of the spectrometer depends on the angle of entry of cosmic muons into the spectrometer in the vertical plane and does not depend on the angle of entry in the horizontal plane. The relative energy resolution of the spectrometer was 16%. Placing an additional lead-scintillation assembly in front of the spectrometer improved the relative energy resolution of the spectrometer to 9%.
- [65] arXiv:2004.07805 (cross-list from nucl-th) [pdf, other]
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Title: Quantifying uncertainties and correlations in the nuclear-matter equation of stateComments: 22 pages, 21 figures, 2 tables; supplemental materialSubjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
We perform statistically rigorous uncertainty quantification (UQ) for chiral effective field theory ($\chi$EFT) applied to infinite nuclear matter up to twice nuclear saturation density. The equation of state (EOS) is based on high-order many-body perturbation theory calculations with consistent nucleon-nucleon and three-nucleon interactions up to fourth order in the $\chi$EFT expansion. From these calculations our newly developed Bayesian machine-learning approach extracts the size and smoothness properties of the correlated EFT truncation error. We then propose a novel extension that uses multi-task machine learning to reveal correlations between the EOS at different proton fractions. The inferred in-medium $\chi$EFT breakdown scale in pure neutron matter and symmetric nuclear matter is consistent with that from free-space nucleon-nucleon scattering. These significant advances allow us to provide posterior distributions for the nuclear saturation point and propagate theoretical uncertainties to derived quantities: the pressure and incompressibility of symmetric nuclear matter, the nuclear symmetry energy, and its derivative. Our results, which are validated by statistical diagnostics, demonstrate that an understanding of truncation-error correlations between different densities and different observables is crucial for reliable UQ. The methods developed here are publicly available as annotated Jupyter notebooks.
Replacements for Fri, 17 Apr 20
- [66] arXiv:1804.09382 (replaced) [pdf, other]
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Title: Gaia Data Release 2: Variable stars in the colour-absolute magnitude diagramAuthors: Gaia Collaboration: L. Eyer, L. Rimoldini, M. Audard, R.I. Anderson, K. Nienartowicz, F. Glass, O. Marchal, M. Grenon, N. Mowlavi, B. Holl, G. Clementini, C. Aerts, T. Mazeh, D.W. Evans, L. Szabados, 438 co-authorsComments: 20 pages, 11 figures, published in Astronomy and Astrophysics (A&A 623, 110, 2019)Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [67] arXiv:1906.05371 (replaced) [pdf, other]
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Title: Streaming instability in turbulent protoplanetary disksComments: Accepted to ApJ, April 14, 2020Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [68] arXiv:1907.00179 (replaced) [pdf, other]
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Title: Forecast for weighing neutrinos in cosmology with SKAComments: 8 pages, 3 figuresJournal-ref: Sci. China-Phys. Mech. Astron. 63, 280411 (2020)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
- [69] arXiv:1907.08095 (replaced) [pdf, other]
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Title: Many-field Inflation: Universality or Prior Dependence?Comments: v2 minor changes to match published version JCAP, 10+1 pagesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
- [70] arXiv:1908.01775 (replaced) [pdf, other]
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Title: Dusty Cloud Acceleration with Multiband RadiationComments: 15 Pages, 14 FiguresJournal-ref: ApJ 893 (2020) 50Subjects: Astrophysics of Galaxies (astro-ph.GA)
- [71] arXiv:1908.07394 (replaced) [pdf, other]
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Title: Electromagnetic Helicity in Classical PhysicsAuthors: Amir JafariSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Classical Physics (physics.class-ph); Plasma Physics (physics.plasm-ph)
- [72] arXiv:1908.08404 (replaced) [pdf, ps, other]
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Title: ALMA CO Observations of a Giant Molecular Cloud in M33: Evidence for High-Mass Star Formation Triggered by Cloud-Cloud CollisionsAuthors: Hidetoshi Sano, Kisetsu Tsuge, Kazuki Tokuda, Kazuyuki Muraoka, Kengo Tachihara, Yumiko Yamane, Mikito Kohno, Shinji Fujita, Rei Enokiya, Gavin Rowell, Nigel Maxted, Miroslav D. Filipovic, Jonathan Knies, Manami Sasaki, Toshikazu Onishi, Paul P. Plucinsky, Yasuo FukuiComments: 13 pages, 10 figures, 1 table, accepted for publication in PASJSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [73] arXiv:1910.00669 (replaced) [pdf, other]
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Title: Redshift/blueshift inside the Schwarzschild black holeAuthors: O. B. ZaslavskiiComments: 21 pages. Substantial revision. To appear in Gen. Rel. GravSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
- [74] arXiv:1910.02128 (replaced) [pdf, other]
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Title: Optical turbulence at Ali, China -- Results from the first year of lunar scintillometer observationsAuthors: Paul Hickson, Lu Feng, Joschua A. Hellemeier, Zhixia Shen, Suijian Xue, Yongqiang Yao, Bin Ma, Hualin Chen, Rui YangSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [75] arXiv:1910.02966 (replaced) [pdf, other]
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Title: Repeated Gravitational Lensing of Gravitational Waves in Hierarchical Black Hole TriplesComments: Accepted to Physical Review D. Comments welcomeSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [76] arXiv:1910.09562 (replaced) [pdf, other]
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Title: Solitosynthesis and Gravitational WavesComments: 6 pages, 2 figures, published versionSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [77] arXiv:1911.02819 (replaced) [pdf, other]
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Title: New achievements in optical turbulence forecast systems in operational modeComments: 8 figures, Proceedings of AO4ELT6 Conference, Quebec City 9-14 June 2019Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Atmospheric and Oceanic Physics (physics.ao-ph)
- [78] arXiv:1911.04557 (replaced) [pdf, other]
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Title: The Milky Way total mass profile as inferred from Gaia DR2Authors: Marius Cautun, Alejandro Benitez-Llambay, Alis J. Deason, Carlos S. Frenk, Azadeh Fattahi, Facundo A. Gómez, Robert J. J. Grand, Kyle A. Oman, Julio F. Navarro, Christine M. SimpsonComments: 21 pages, 14 figures, main results: figs 3, 7, 10 and 11; MNRAS accepted version, code and resources available at this https URLSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [79] arXiv:1912.00655 (replaced) [pdf, other]
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Title: Probing the azimuthal environment of galaxies around clusters. From cluster core to cosmic filamentsComments: accepted for publication in A&A, 13 pagesJournal-ref: A&A 635, A195 (2020)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [80] arXiv:2001.00587 (replaced) [pdf, other]
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Title: ZTF Early Observations of Type Ia Supernovae III: Early-Time Colors as a Test for Explosion Models and Multiple PopulationsAuthors: Mattia Bulla, Adam A. Miller, Yuhan Yao, Luc Dessart, Suhail Dhawan, Semeli Papadogiannakis, Rahul Biswas, Ariel Goobar, S. R. Kulkarni, Jakob Nordin, Peter Nugent, Abigail Polin, Jesper Sollerman, Eric C. Bellm, Michael W. Coughlin, Richard Dekany, V. Zach Golkhou, Matthew J. Graham, Mansi M. Kasliwal, Thomas Kupfer, Russ R. Laher, Frank J. Masci, Michael Porter, Ben Rusholme, David L. ShupeComments: 17 pages, 9 figures, 1 table; accepted for publication in ApJ; fixed error in time of first light + selection criterion changed; sample increased from 38 to 65 events; conclusions unchangedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [81] arXiv:2001.01932 (replaced) [pdf, ps, other]
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Title: The mean tilt of sunspot bipolar regions: theory, simulations and comparison with observationsComments: 12 pages, 4 figures, mn2e.cls , revised, final versionSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph)
- [82] arXiv:2001.02187 (replaced) [pdf, other]
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Title: Explaining the chemical trajectories of accreted and in-situ halo stars of the Milky WayComments: Accepted version MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [83] arXiv:2001.02235 (replaced) [pdf, other]
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Title: Possible Transfer of Life by Earth-Grazing Objects to Exoplanetary SystemsComments: 4 pages, 2 figures; accepted for publication in the journal "Life"Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
- [84] arXiv:2001.11063 (replaced) [pdf, other]
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Title: The VANDELS survey: A strong correlation between Ly$α$ equivalent width and stellar metallicity at $\mathbf{3\leq z \leq 5}$Authors: F. Cullen, R. J. McLure, J. S. Dunlop, A. C. Carnall, D. J. McLeod, A. E. Shapley, R. Amorín, M. Bolzonella, M. Castellano, A. Cimatti, M. Cirasuolo, O. Cucciati, A. Fontana, F. Fontanot, B. Garilli, L. Guaita, M. J. Jarvis, L. Pentericci, L. Pozzetti, M. Talia, G. Zamorani, A. Calabrò, G. Cresci, J. P. U. Fynbo, N. P. Hathi, M. Giavalisco, A. Koekemoer, F. Mannucci, A. SaxenaComments: 10 pages, 6 figures, MNRAS acceptedSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [85] arXiv:2002.05165 (replaced) [pdf, other]
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Title: Dark Photon Oscillations in Our Inhomogeneous UniverseComments: 5+8 pages, 3+6 figures; v2, added appendix on energy injection assumptions, minor updates to figures, results and conclusions unchangedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
- [86] arXiv:2003.02994 (replaced) [pdf, ps, other]
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Title: Semi-analytic Models for Electron Acceleration in Weak ICM ShocksAuthors: Hyesung KangComments: 9 pages, 5 figures, to appear in June issue of Journal of the Korean Astronomical SocietySubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [87] arXiv:2003.10781 (replaced) [pdf, other]
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Title: Tidal deformations of hybrid stars with sharp phase transitions and elastic crustsComments: 11 pages, 3 figures. Minor changes to the abstract. Accepted for publication in ApJSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
- [88] arXiv:2004.04740 (replaced) [pdf, other]
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Title: Dark matter and dark radiation from evaporating primordial black holesAuthors: Isabella MasinaComments: v1: 29 pages, 9 figures; v2: 29 pages, 9 figures, added referencesSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [89] arXiv:2004.06186 (replaced) [pdf, other]
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Title: Nanoflare Theory RevisitedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph)
- [90] arXiv:2004.06501 (replaced) [pdf, other]
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Title: Dynamical cloud formation traced by atomic and molecular gasAuthors: H. Beuther, Y. Wang, J.D. Soler, H. Linz, J. Henshaw, E. Vazquez-Semadeni, G. Gomez, S. Ragan, Th. Henning, S.C.O. Glover, M.-Y. Lee, R.GuestenComments: 13 pages, 15 figures, Astronomy & Astrophysics in press, a higher resolution version can be found at this http URLSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [91] arXiv:2004.07185 (replaced) [pdf, other]
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Title: The Flux Distribution of Sgr A*Authors: The GRAVITY Collaboration: R. Abuter, A. Amorim, M Bauboeck, H. Bonnet, W. Brandner, V. Cardoso, Y. Clenet, P.T. de Zeeuw, J. Dexter, A. Eckart, F. Eisenhauer, N.M. Förster Schreiber, P. Garcia, F. Gao, E. Gendron, R. Genzel, S. Gillessen, M. Habibi, X. Haubois, T. Henning, S. Hippler, M. Horrobin, L. Jocou, A. Jimenez-Rosales, L. Jochum, L. Jocou, A. Kaufer, P. Kervella, S. Lacour, V. Lapeyrère, J.-B. Le Bouquin, P. Léna, M. Nowak, T. Ott, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, G. Ponti, G. Rodriguez Coira, J. Shangguan, S. Scheithauer, J. Stadler, O. Straub, C. Straubmeier, E. Sturm, L.J. Tacconi, K.R.W. Tristram, F. Vincent, S.D. von Fellenberg, I. Waisberg, F. Widmann, E. Wieprecht, E. Wiezorrek, J. Woillez, S. Yazici, G. ZinsSubjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); General Relativity and Quantum Cosmology (gr-qc)
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