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New submissions for Tue, 14 Jan 20

[1]  arXiv:2001.03619 [pdf, other]

Title: Candidate Population III stellar complex at z=6.629 in the MUSE Deep Lensed Field

Authors: E. Vanzella, M. Meneghetti, G. B. Caminha, M. Castellano, F. Calura, P. Rosati, C. Grillo, M. Dijkstra, M. Gronke, E. Sani, A. Mercurio, P. Tozzi, M. Nonino, S. Cristiani, M. Mignoli, L. Pentericci, R. Gilli, T. Treu, K. Caputi, G. Cupani, A. Fontana, A. Grazian, I. Balestra

Comments: 4 pages, 3 figures and 1 table. Submitted. Comments welcome

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We discovered a strongly lensed (\mu >40) Lya emission at z=6.629 (S/N~18) in the MUSE Deep Lensed Field (MDLF) targeting the Hubble Frontier Field galaxy cluster MACS~J0416. Dedicated lensing simulations imply that the Lya emitting region necessarily crosses the caustic. The arc-like shape of the Lya extends 3 arcsec on the observed plane and is the result of two merged multiple images, each one with a de-lensed Lya luminosity L<~2.8 x 10^(40) erg/s arising from a confined region (< 150 pc effective radius). A spatially unresolved HST counterpart is barely detected at S/N~2 after stacking the near-infrared bands, corresponding to an observed(intrinsic) magnitude m_(1500)>~30.8(>~35.0). The inferred rest-frame Lya equivalent width is EWo > 1120 A if the IGM transmission is T(IGM)<0.5. The low luminosities and the extremely large Lya EWo match the case of a Population~III star complex made of several dozens stars (~ 10^4 Msun) which irradiate a HII region crossing the caustic. While the Lya and stellar continuum are among the faintest ever observed at this redshift, the continuum and the Lya emissions could be affected by differential magnification, possibly biasing the EWo estimate. The aforementioned tentative HST detection tend to favor a large EWo, making such a faint Pop~III candidate a key target for the James Webb Space Telescope and Extremely Large Telescopes.

[2]  arXiv:2001.03620 [pdf, other]

Title: Gravitational-wave detection and parameter estimation for accreting black-hole binaries and their electromagnetic counterpart

Authors: Andrea Caputo, Laura Sberna, Alexandre Toubiana, Stanislav Babak, Enrico Barausse, Sylvain Marsat, Paolo Pani

Comments: 14 pages, 8 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

We study the impact of gas accretion on the orbital evolution of black-hole binaries initially at large separation in the band of the planned Laser Interferometer Space Antenna (LISA). We focus on two sources: (i)~stellar-origin black-hole binaries~(SOBHBs) that can migrate from the LISA band to the band of ground-based gravitational-wave observatories within weeks/months; and (ii) intermediate-mass black-hole binaries~(IMBHBs) in the LISA band only. Because of the large number of observable gravitational-wave cycles, the phase evolution of these systems needs to be modeled to great accuracy to avoid biasing the estimation of the source parameters. Accretion affects the gravitational-wave phase at negative ($-4$) post-Newtonian order, and is therefore dominant for binaries at large separations. If accretion takes place at the Eddington or at super-Eddington rate, it will leave a detectable imprint on the dynamics of SOBHBs. In optimistic astrophysical scenarios, a multiwavelength strategy with LISA and a ground-based interferometer can detect about $10$ (a few) SOBHB events for which the accretion rate can be measured at $50\%$ ($10\%$) level. In all cases the sky position can be identified within much less than $0.4\,{\rm deg}^2$ uncertainty. Likewise, accretion at $\gtrsim 10\%$ ($\gtrsim 100\%$) of the Eddington rate can be measured in IMBHBs up to redshift $z\approx 0.1$ ($z\approx 0.5$), and the position of these sources can be identified within less than $0.01\,{\rm deg}^2$ uncertainty. Altogether, a detection of SOBHBs or IMBHBs would allow for targeted searches of electromagnetic counterparts to black-hole mergers in gas-rich environments with future X-ray detectors (such as Athena) and radio observatories (such as SKA).

[3]  arXiv:2001.03621 [pdf, other]

Title: Evaluation of probabilistic photometric redshift estimation approaches for LSST

Authors: S.J. Schmidt, A.I. Malz, J.Y.H. Soo, I.A. Almosallam, M. Brescia, S. Cavuoti, J. Cohen-Tanugi, A.J. Connolly, J. DeRose, P.E. Freeman, M.L. Graham, K.G. Iyer, M.J. Jarvis, J.B. Kalmbach, E. Kovacs, A.B. Lee, G. Longo, C.B. Morrison, J.A. Newman, E. Nourbakhsh, E. Nuss, T. Pospisil, H. Tranin, R.H. Wechsler, R. Zhou, R. Izbicki, The LSST Dark Energy Science Collaboration

Comments: submitted to MNRAS

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)

Many scientific investigations of photometric galaxy surveys require redshift estimates, whose uncertainty properties are best encapsulated by photometric redshift (photo-z) posterior probability density functions (PDFs). A plethora of photo-z PDF estimation methodologies abound, producing discrepant results with no consensus on a preferred approach. We present the results of a comprehensive experiment comparing twelve photo-z algorithms applied to mock data produced for the Large Synoptic Survey Telescope (LSST) Dark Energy Science Collaboration (DESC). By supplying perfect prior information, in the form of the complete template library and a representative training set as inputs to each code, we demonstrate the impact of the assumptions underlying each technique on the output photo-z PDFs. In the absence of a notion of true, unbiased photo-z PDFs, we evaluate and interpret multiple metrics of the ensemble properties of the derived photo-z PDFs as well as traditional reductions to photo-z point estimates. We report systematic biases and overall over/under-breadth of the photo-z PDFs of many popular codes, which may indicate avenues for improvement in the algorithms or implementations. Furthermore, we raise attention to the limitations of established metrics for assessing photo-z PDF accuracy; though we identify the conditional density estimate (CDE) loss as a promising metric of photo-z PDF performance in the case where true redshifts are available but true photo-z PDFs are not, we emphasize the need for science-specific performance metrics.

[4]  arXiv:2001.03624 [pdf]

Title: The Expansion of the Universe is Faster than Expected

Authors: Adam G. Riess

Comments: Published Nature Reviews Physics, Year In Review, 2019, January 2020

Journal-ref: Nat Rev Phys 2, 10-12,2020

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

The present rate of the expansion of our Universe, the Hubble constant, can be predicted from the cosmological model using measurements of the early Universe, or more directly measured from the late Universe. But as these measurements improved, a surprising disagreement between the two appeared. In 2019, a number of independent measurements of the late Universe using different methods and data provided consistent results making the discrepancy with the early Universe predictions increasingly hard to ignore. We review key advances realized by 2019:
-- The local or late Universe measurement of the Hubble constant improved from 10% uncertainty twenty years ago to under 2% by the end of 2019.
-- In 2019, multiple independent teams presented measurements with different methods and different calibrations to produce consistent results.
-- These late Universe estimations disagree at 4$\sigma$ to 6$\sigma$ with predictions made from the Cosmic Microwave Background in conjunction with the standard cosmological model, a disagreement that is hard to explain or ignore.

[5]  arXiv:2001.03625 [pdf, other]

Title: Stratified disc wind models for the AGN broad-line region: ultraviolet, optical and X-ray properties

Authors: James H. Matthews, Christian Knigge, Nick Higginbottom, Knox S. Long, Stuart A. Sim, Samuel W. Mangham, Edward J. Parkinson, Henrietta A. Hewitt

Comments: Accepted to MNRAS. 20 pages, 13 figures plus appendix. Supplementary plots, some simulation data and demo notebooks can be found at this https URL

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The origin, geometry and kinematics of the broad line region (BLR) gas in quasars and active galactic nuclei (AGN) are uncertain. We demonstrate that clumpy biconical disc winds illuminated by an AGN continuum can produce BLR-like spectra. We first use a simple toy model to illustrate that disc winds make quite good BLR candidates, because they are self-shielded flows and can cover a large portion of the ionizing flux-density ($\phi_H$-$n_H$) plane. We then conduct Monte Carlo radiative transfer and photoionization calculations, which fully account for self-shielding and multiple scattering in a non-spherical geometry. The emergent model spectra show broad emission lines with equivalent widths and line ratios comparable to those observed in AGN, provided that the wind has a volume filling factor of $f_V\lesssim0.1$. Similar emission line spectra are produced for a variety of wind geometries (polar or equatorial) and for launch radii that differ by an order of magnitude. The line emission arises almost exclusively from plasma travelling below the escape velocity, implying that `failed winds' are important BLR candidates. The behaviour of a line-emitting wind (and possibly any `smooth flow' BLR model) is similar to that of the locally optimally-emitting cloud (LOC) model originally proposed by Baldwin et al (1995), except that the gradients in ionization state and temperature are large-scale and continuous, rather than within or between distinct clouds. Our models also produce UV absorption lines and X-ray absorption features, and the stratified ionization structure can partially explain the different classes of broad absorption line quasars.

[6]  arXiv:2001.03626 [pdf, other]

Title: Nuclear Star Clusters

Authors: Nadine Neumayer, Anil Seth, Torsten Boeker

Comments: Invited review to appear in The Astronomy and Astrophysics Review, 53 pages, 13 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We review the current knowledge about nuclear star clusters (NSCs), the spectacularly dense and massive assemblies of stars found at the centers of most galaxies. Recent observational and theoretical work suggest that many NSC properties, including their masses, densities, and stellar populations vary with the properties of their host galaxies. Understanding the formation, growth, and ultimate fate of NSCs therefore is crucial for a complete picture of galaxy evolution. Throughout the review, we attempt to combine and distill the available evidence into a coherent picture of NSC evolution. Combined, this evidence points to a clear transition mass in galaxies of ~10^9 solar masses where the characteristics of nuclear star clusters change. We argue that at lower masses, NSCs are formed primarily from globular clusters that inspiral into the center of the galaxy, while at higher masses, star formation within the nucleus forms the bulk of the NSC. We also discuss the coexistence of NSCs and central black holes, and how their growth may be linked. The extreme densities of NSCs and their interaction with massive black holes lead to a wide range of unique phenomena including tidal disruption and gravitational wave events. Lastly, we review the evidence that many NSCs end up in the halos of massive galaxies stripped of the stars that surrounded them, thus providing valuable tracers of the galaxies' accretion histories.

[7]  arXiv:2001.03627 [pdf, ps, other]

Title: High reddening patches in Gaia DR2. Possible artifacts or indication of star formation at the edge of the Galactic disk

Authors: Leire Beitia-Antero, Ana Inés Gómez de Castro, Raúl de la Fuente Marcos

Comments: 6 pages, 8 figures. Accepted for publication in A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Context: Deep GALEX UV data show that the extreme outskirts of some spiral galaxies are teeming with star formation. Such young stellar populations evolving so far away from the bulk of their host galaxies challenge our overall understanding of how star formation proceeds at galactic scales. It is at present unclear whether our own Milky Way may also exhibit ongoing and recent star formation beyond the conventional edge of the disk ($\sim 15$ kpc). Aims: Using \textit{Gaia} DR2 data, we aim to determine if such a population is present in the Galactic halo, beyond the nominal radius of the Milky Way disk. Methods: We studied the kinematics of \textit{Gaia} DR2 sources with parallax values between 1/60 and 1/30 milliarcseconds towards two regions that show abnormally high values of extinction and reddening; the results are compared with predictions from GALAXIA Galactic model. We also plotted the color-magnitude (CM) diagrams with heliocentric distances computed inverting the parallaxes, and studied the effects of the large parallax errors by Monte Carlo sampling. Results: The kinematics point towards a Galactic origin for one of the regions, while the provenance of the stars in the other is not clear. A spectroscopic analysis of some of the sources in the first region confirms that they are located in the halo. The CM diagram of the sources suggests that some of them are young.

[8]  arXiv:2001.03628 [pdf, ps, other]

Title: Evidence for $\gtrsim{4}$ Gyr timescales of neutron star mergers from Galactic archaeology

Authors: Ása Skúladóttir, Stefania Salvadori

Comments: Letter accepted in A&A, 6 pages, 3 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

The nucleosynthetic site of the rapid ($r$) neutron-capture process is currently being debated. The direct detection of the neutron star merger GW170817, through gravitational waves and electromagnetic radiation, has confirmed such events as important sources of the $r$-process elements. However, chemical evolution models are not able to reproduce the observed chemical abundances in the Milky Way when neutron star mergers are assumed to be the only $r$-process site and realistic time distributions of such events are taken into account. Now for the first time, we combine all the available observational evidence of the Milky Way and its dwarf galaxy satellites to show that the data can only be explained if there are (at least) two distinct $r$-process sites: a quick source with timescales comparable to core-collapse supernovae, $t_{quick}\lesssim10^8$ yr, and a delayed source with characteristic timescales $t_{delayed}\gtrsim4$ Gyr. The delayed $r$-process source most probably originates in neutron star mergers, as the timescale fits well with that estimated for GW170817. Given the short timescales of the quick source, it is likely associated with massive stars, though a specific fast-track channel for compact object mergers cannot be excluded at this point. Our approach demonstrates that only by looking at all the available data will we be able to solve the puzzle that is the $r$-process.

[9]  arXiv:2001.03641 [pdf, other]

Title: A hyper luminous starburst at z=4.72 magnified by a lensing galaxy pair at z=1.48

Authors: L. Ciesla, M. Béthermin, E. Daddi, J. Richard, T. Diaz-Santos, M. T. Sargent, D. Elbaz, M. Boquien, T. Wang, C. Schreiber, C. Yang, J. Zabl, M. Fraser, M. Aravena, R. J. Assef, A. J. Baker, A. Beelen, A. Boselli, F. Bournaud, D. Burgarella, V. Charmandaris, P. Côté, B. Epinat, L. Ferrarese, R. Gobat, O. Ilbert

Comments: 14 pages, 15 figures, accepted for publication in A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[Abridged] We discovered in the Herschel Reference Survey an extremely bright IR source with $S_{500}$~120mJy (Red Virgo 4 - RV4). Based on IRAM/EMIR and IRAM/NOEMA detections of the CO(5-4), CO(4-3), and [CI] lines, RV4 is located at z=4.724, yielding a total observed L$_{IR}$ of 1.1+/-0.6x0$^{14}$L$_{\odot}$. At the position of the Herschel emission, three blobs are detected with the VLA at 10cm. The CO(5-4) line detection of each blob confirms that they are at the same redshift with the same line width, indicating that they are multiple images of the same source. In Spitzer and deep optical observations, two sources, High-z Lens 1 (HL1) West and HL1 East, are detected at the center of the three VLA/NOEMA blobs. These two sources are placed at z=1.48 with XSHOOTER spectra, suggesting that they could be merging and gravitationally lensing the emission of RV4. HL1 is the second most distant lens known to date in strong lensing systems. The Einstein radius of the lensing system is 2.2"+/-0.2 (20kpc). The high redshift of HL1 and the large Einstein radius are highly unusual for a strong lensing system. We present the ISM properties of the background source RV4. Different estimates of the gas depletion time yield low values suggesting that RV4 is a SB galaxy. Among all high-z SMGs, this source exhibits one of the lowest L$_{[CI]}$ to L$_{IR}$ ratios, 3.2+/-0.9x10$^{-6}$, suggesting an extremely short gas tdepl of only 14+/-5Myr. It also shows a relatively high L$_{[CI]}$ to L$_{CO(4-3)}$ ratio (0.7+/-0.2) and low L$_{CO(5-4)}$ to L$_{IR}$ ratio (only ~50% of the value expected for normal galaxies) hinting a low density of gas. Finally, we discuss that the short tdepl of RV4 can be explained by either a very high SFE, which is difficult to reconcile with major mergers simulations of high-z galaxies, or a rapid decrease of SF, which would bias the estimate of tdepl toward low value.

[10]  arXiv:2001.03654 [pdf, other]

Title: Relativistic three-body effects in hierarchical triples

Authors: Halston Lim, Carl L. Rodriguez

Comments: 25 pages, 8 figures. Submitted to PRD 12/30/19

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

The hierarchical three-body problem has many applications in relativistic astrophysics, and can potentially explain all of the binary black hole mergers detected by LIGO/Virgo. However, the majority of studies have only included relativistic corrections to the two-body equations of motion, and have ignored the relativistic effects that arise in the presence of a third body. We revisit this problem and develop a fully consistent derivation of the secular three-body problem to first post-Newtonian order. We start with the Einstein-Infeld-Hoffman equations for a three-body system and expand the accelerations as a power series in the ratio of the semi-major axes of the inner ($a_1$) and outer ($a_2$) binary. We then perform a post-Keplerian, two-parameter expansion of the single orbit-averaged Lagrange planetary equations in $\delta = v^2/c^2$ and $\epsilon = a_1/a_2$ using the method of multiple scales. It is well established that eccentricity growth through the Lidov-Kozai (LK) mechanism can be suppressed or amplified by two-body 1pN (2BpN) precession. In this study, we derive and investigate three-body 1pN (3BpN) effects. We find that these effects can lead to eccentricity growth in triples, occurring over hundreds of LK cycles. The octupole terms can enhance these effects and lead to even greater eccentricities. In such cases, inclusion of these effects can substantially alter the evolution of three-body systems as compared to an analysis in which they are neglected. Careful analysis of post-Newtonian three-body effects will be important to understand the formation and properties of coalescing binaries that form via three-body dynamical processes.

[11]  arXiv:2001.03668 [pdf, other]

Title: Understanding the atmospheric properties and chemical composition of the ultra-hot Jupiter HAT-P-7b II. Mapping the effects of gas kinetics

Authors: Karan Molaverdikhani, Christiane Helling, Ben W.P. Lew, Ryan J. MacDonald, Dominic Samra, Nicolas Iro, Peter Woitke, Vivien Parmentier

Comments: 26 page, 20 figures, accepted in A&A

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

The atmospheres of ultra-hot Jupiters are commonly considered to be at thermochemical equilibrium. We aim to provide disequilibrium chemistry maps for a global understanding of the chemistry in HAT-P-7b's atmosphere and assess the importance of disequilibrium chemistry on UHJs.
We apply a hierarchical modelling approach utilising 97 1D atmospheric profiles from 3D GCM of HAT-P-7b. For each 1D profile, we evaluate our kinetic cloud formation model consistently with the local gas-phase composition in chemical equilibrium. We then evaluate quenching results from a zeroth-order approximation in comparison to a kinetic gas-phase approach.
We find that the zeroth-order approach of estimating quenching points agrees well with the full gas-kinetic modeling results. Chemical disequilibrium has the greatest effect on the nightside and morning abundance of species such as H, H$_2$O, CH$_4$, CO$_2$, HCN, and all C$_n$H$_m$ molecules; heavier C$_n$H$_m$ molecules are more affected by disequilibrium processes. CO abundance, however, is affected only marginally. While dayside abundances also notably change, those around the evening terminator of HAT-P-7b are the least affected by disequilibrium processes. The latter finding may partially explain the consistency of observed transmission spectra of UHJs with atmospheres in thermochemical equilibrium. Photochemistry only negligibly affects molecular abundances and quenching levels.
In general, the quenching points of HAT-P-7b's atmosphere are at much lower pressures in comparison to the cooler hot-jupiters. We propose several avenues to look for the effect of disequilibrium processes on UHJs that are, in general, based on abundance and opacity measurements at different local times. It remains a challenge to completely disentangle this from the chemical effects of clouds and that of a primordial non-solar abundance.

[12]  arXiv:2001.03681 [pdf, other]

Title: The Future of astronomical archives: reaching out to and engaging broader communities

Authors: Raffaele D'Abrusco, Glenn Becker, Michael McCollough, Sinh Thong, David VanStone, Sherry Winkelman

Comments: Proceedings of ADASS 2019

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

The importance of archival science increases significantly for astrophysical observatories as they mature and their archive holdings grow in size and complexity. Further enhancing the science return of archival data requires engaging a larger audience than the mission reference community, mostly because of the growth of interest in multi-wavelength and transient/time variability research. Such a goal, though, can be difficult to achieve. In this paper I will describe a different approach to this question that, while minimizing technological friction and leveraging existing services, makes archival observations more accessible and increases our capability to proactively engage astronomers on potentially interesting archival records. Inspired by this strategy, the Chandra Data Archive team is working on two specific experimental projects that will hopefully demonstrate their potential while contributing to the maximization of the scientific return of the Chandra mission.

[13]  arXiv:2001.03683 [pdf, other]

Title: The Swift Bulge Survey: optical and near-IR follow-up featuring a likely symbiotic X-ray binary & a focused wind CV

Authors: A. W. Shaw, C. O. Heinke, T. J. Maccarone, G. R. Sivakoff, J. Strader, A. Bahramian, N. Degenaar, J. A. Kennen, E. Kuulkers, A. Rau, L. E. Rivera Sandoval, L. Shishkovsky, S. J. Swihart, A. J. Tetarenko, R. Wijnands, J. J. M. in 't Zand

Comments: 18 pages, 11 figures, accepted for publication in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

The nature of very faint X-ray transients (VFXTs) - transient X-ray sources that peak at luminosities $L_X\lesssim10^{36} {\rm erg s^{-1}}$ - is poorly understood. The faint and often short-lived outbursts make characterising VFXTs and their multi-wavelength counterparts difficult. In 2017 April we initiated the Swift Bulge Survey, a shallow X-ray survey of $\sim$16 square degrees around the Galactic centre with the Neil Gehrels Swift Observatory. The survey has been designed to detect new and known VFXTs, with follow-up programmes arranged to study their multi-wavelength counterparts. Here we detail the optical and near-infrared follow-up of four sources detected in the first year of the Swift Bulge Survey. The known neutron star binary IGR J17445-2747 has a K4III donor, indicating a potential symbiotic X-ray binary nature and the first such source to show X-ray bursts. We also find one nearby M-dwarf (1SXPS J174215.0-291453) and one system without a clear near-IR counterpart (Swift J175233.9-290952). Finally, 3XMM J174417.2-293944 has a subgiant donor, an 8.7 d orbital period, and a likely white dwarf accretor; we argue that this is the first detection of a white dwarf accreting from a gravitationally focused wind. A key finding of our follow-up campaign is that binaries containing (sub)giant stars may make a substantial contribution to the VFXT population.

[14]  arXiv:2001.03695 [pdf, other]

Title: Equilibrium Tidal Response of Jupiter: Detectability by Juno

Authors: Sean M Wahl, Marzia Parisi, William M Folkner, William B Hubbard, Burkhard Militzer

Comments: 26 Pages, 11 figures, 7 Tables, Accepted to ApJ

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

An observation of Jupiter's tidal response is anticipated for the on-going Juno spacecraft mission. We combine self-consistent, numerical models of Jupiter's equilibrium tidal response with observed Doppler shifts from the Juno gravity science experiment to test the sensitivity of the spacecraft to tides raised by the Galilean satellites and the Sun. The concentric Maclaurin spheroid (CMS) method finds the equilibrium shape and gravity field of a rotating, liquid planet with the tide raised by a satellite, expanded in Love numbers ($k_{nm}$). We present improvements to CMS theory that eliminate an unphysical center of mass offset and study in detail the convergence behavior of the CMS approach. We demonstrate that the dependence of $k_{nm}$ with orbital distance is important when considering the combined tidal response for Jupiter. Conversely, the details of the interior structure have a negligible influence on $k_{nm}$, for models that match the zonal harmonics $J_2$, $J_4$ and $J_6$, already measured to high precision by Juno. As the mission continues, improved coverage of Jupiter's gravity field at different phases of Io's orbit is expected to yield an observed value for the degree-2 Love number ($k_{22}$) and potentially select higher--degree $k_{nm}$. We present a test of the sensitivity of the Juno Doppler signal to the calculated $k_{nm}$, which suggests the detectability of $k_{33}$, $k_{42}$ and $k_{31}$, in addition to $k_{22}$. A mismatch of a robust Juno observation with the remarkably small range in calculated Io equilibrium $k_{22}=0.58976\pm0.0001$, would indicate a heretofore uncharacterized dynamic contribution to the tides.

[15]  arXiv:2001.03699 [pdf, other]

Title: Deciphering Lyman $α$ blob 1 with deep MUSE observations

Authors: Edmund Christian Herenz, Matthew Hayes, Claudia Scarlata

Comments: 24 pages, 14 figures. Submitted to A&A, comments welcome

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Context: Lyman $\alpha$ blobs (LABs) are large-scale radio-quiet Lyman $\alpha$ (Ly$\alpha$) nebula at high-$z$ that occur predominantly in overdense proto-cluster regions. Especially the prototypical SSA22a-LAB1 at $z=3.1$ has become an observational reference for LABs across the electromagnetic spectrum.
Aims: We want to understand the powering mechanisms that drive the LAB to gain empirical insights into galaxy formation processes within a rare dense environment at high-$z$.
Methods: LAB 1 was observed for 17.5h with the VLT/MUSE integral-field spectrograph. We produced optimally extracted narrow band images in Ly$\alpha$ $\lambda1216$, HeII $\lambda1640$, and we tried to detect CIV $\lambda1549$ emission. By using a moment based analysis we mapped the kinematics of the blob.
Results: We detect Ly$\alpha$ emission to surface-brightness limits of $10^{-19}$erg s$^{-1}$cm$^{-2}$arcsec$^{-2}$. At this depth we reveal a bridge between LAB 1 and its northern neighbour LAB 8, as well as a shell-like filament towards the south of LAB 1. We find a coherent large scale east-west $\sim$1000 km s$^{-1}$ velocity gradient that is aligned perpendicular to the major axis of the blob. We detect HeII emission in three distinct regions, but we can only provide upper limits for CIV.
Conclusions: Various gas excitation mechanisms are at play in LAB 1: Ionising radiation and feedback effects dominate near the embedded galaxies, while Ly$\alpha$ scattering is contributing at larger distances. The HeII/Ly$\alpha$ ratios combined with the upper limits on CIV/Ly$\alpha$ ratios favour shock models over photo-ionisation. The alignment of the angular momentum vector parallel to the morphological principal axis appears odds with the predicted norm for high-mass halos, but likely reflects that LAB\,1 resides at a node of multiple intersecting filaments of the cosmic web.
(Abridged)

[16]  arXiv:2001.03716 [pdf, other]

Title: Self-similar Blast Wave for A Two-component Fluid with Variable Adiabatic Index

Authors: Yiran Zhang, Edison Liang, Siming Liu

Comments: Submitted to ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We propose a self-similar (SS) solution to hydrodynamic non-relativistic flow behind a spherical strong blast wave (BW) passing through a homogeneous plasma with efficient relativistic particle acceleration at the shock front. The flow is described by an ideal two-fluid model with a relativistic component so that the post-shock gas has an effective SS adiabatic index $ \gamma $ varying from $ 5/3 $ to $ 4/3 $. This solution is calculated numerically and compared with the standard Sedov solution. We find that the BW center in our solution is dominated by the relativistic component with $ \gamma =4/3 $ for the divergence of expansion there, and the relativistic component dominates the interior for a moderate acceleration efficiency at the shock front. The overall efficiency of relativistic particle acceleration can be enhanced by a factor of $ 2 $ due to the slower adiabatic energy loss rate of the relativistic component during expansion. Tendency of the dominance by the relativistic component may be common in expanding astrophysical two-fluid systems such as supernova remnants, lobes of radio galaxies.

[17]  arXiv:2001.03721 [pdf, ps, other]

Title: Comparative Study of Data-driven Solar Coronal Field Models Using a Flux Emergence Simulation as a Ground-truth Data Set

Authors: Shin Toriumi, Shinsuke Takasao, Mark C.M. Cheung, Chaowei Jiang, Yang Guo, Keiji Hayashi, Satoshi Inoue

Comments: 17 pages, 11 figures, 1 table, accepted for publication in ApJ. The ground-truth dataset (photospheric slices of the flux emergence simulation) is available online at this https URL

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

For a better understanding of magnetic field in the solar corona and dynamic activities such as flares and coronal mass ejections, it is crucial to measure the time-evolving coronal field and accurately estimate the magnetic energy. Recently, a new modeling technique called the data-driven coronal field model, in which the time evolution of magnetic field is driven by a sequence of photospheric magnetic and velocity field maps, has been developed and revealed the dynamics of flare-productive active regions. Here we report on the first qualitative and quantitative assessment of different data-driven models using a magnetic flux emergence simulation as a ground-truth (GT) data set. We compare the GT field with those reconstructed from the GT photospheric field by four data-driven algorithms. It is found that, at least, the flux rope structure is reproduced in all coronal field models. Quantitatively, however, the results show a certain degree of model dependence. In most cases, the magnetic energies and relative magnetic helicity are comparable to or at most twice of the GT values. The reproduced flux ropes have a sigmoidal shape (consistent with GT) of various sizes, a vertically-standing magnetic torus, or a packed structure. The observed discrepancies can be attributed to the highly non-force-free input photospheric field, from which the coronal field is reconstructed, and to the modeling constraints such as the treatment of background atmosphere, the bottom boundary setting, and the spatial resolution.

[18]  arXiv:2001.03775 [pdf, other]

Title: Interacting Dark Sectors in Anisotropic Universe: Observational Constraints and $H_{0}$ Tension

Authors: Hassan Amirhashchi, Anil Kumar Yadav

Comments: 11 pages, 21 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

The present study reveals observational constraints on the coupling between dark components of anisotropic Bianchi type I universe. We assume interaction between dark matter and dark energy and split the continuity equation with inclusion of interaction term $\Gamma$. Two scenarios have been considered (i) when coupling between dark components is constant and (ii) when it is a function of redshift ($z$). Metropolis-Hasting algorithm has been used to perform Monte Carlo Markov Chain (MCMC) analysis by using observational Hubble data obtained from cosmic chronometric (CC) technique, cosmic microwave background (CMB) baryon acoustic oscillation (BAO), Pantheon compilation of Supernovae type Ia (SNIa), their joint combination and a gaussian prior on the Hubble parameter $H_{0}$. It is obtained that the combination of all databases plus $H_{0}$ prior marginalized over a present dark energy density gives stringent constraints on the current value of coupling as $-0.001<\delta<0.041$ in constant coupling model and $-0.042<\delta<0.053$ in varying coupling model at 68\% confident level. In general, for both models, we found $\omega^{X}\approx -1$ and $\delta(\delta_{0})\approx 0$ which indicate that still recent data favor uncoupled $\Lambda$CDM model. Our estimations show that in constant coupling model $H_{0}=73.9^{+1.5}_{-0.95}$ which naturally solves the Hubble tension problem. In other word, in constant coupling model, we did not find any disagreement between our estimated $H_{0}$ and those reported by Hubble space telescope (HST) and large scale structure (LSS) experiments.

[19]  arXiv:2001.03791 [pdf, other]

Title: On the wind-driven relaxation cycle in accretion disks

Authors: Shalini Ganguly, Daniel Proga

Comments: 10 pages, 7 figures, 2 tables; Accepted for publication in ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

A disk wind can cause perturbations that propagate throughout the disk via diffusive processes. On reaching the inner disk, these perturbations can change the disk luminosity, which in turn, can change the wind mass loss rate, $\dot{M}_w$. It has been argued that this so-called "wind driven relaxation cycle" might explain the observed variability in some disk accreting objects. Here, we study the response of the innermost mass accretion rate $\dot{M}_a$ to the loss of matter at different rates and radii. We allow the wind launching radius, $R_L$, to scale with $\dot{M}_a$. We computed a grid of time-dependent models for various $\dot{M}_w$-$\dot{M}_a$ and $R_{L}$-$\dot{M}_a$ dependencies. We find that the disk behaviour significantly differs for the 'variable $R_L$' case compared to the 'fixed $R_L$' case. In particular, much stronger winds are required to destabilize the disk in the former than the latter case. However, the $\dot{M}_a$ amplitude does not grow significantly even for unstable cases because the oscillations saturate at a low level either due to disk depletion or due to the wind being launched at very small radii, or both. This result implies that disk winds are unlikely to be responsible for state transitions as those require large changes in the inner disk. Despite modest changes at the inner disk regions, the disk surface density at large radii can vary with a large amplitude, i.e., from 0 to a few factors of the steady state value. This dramatic variation of the outer disk could have observable consequences.

[20]  arXiv:2001.03795 [pdf, other]

Title: Splash Bridge Models of Inclined, Gas-Rich, Direct Galaxy Collisions

Authors: Travis Yeager, Curt Struck

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Splash bridges are formed from the direct inelastic collision of gas-rich galaxies. Recent multi-wavelength observations of the Taffy galaxies, UGC 12914/15, have revealed complicated gas structures in the bridge. We have upgraded the sticky particle simulation code of Yeager et al., 2019, by adding: the ability to adjust the relative inclination of the gas discs, the ability to track cloud-cloud collisions over time, and additional cooling processes. Inclination effects lead to various morphological features, including filamentary streams of gas stripped from the smaller galactic disc. The offset of disc centres at impact determines whether or not these streams flow in a single direction or multiple directions, even transverse to the motion of the two galaxies. We also find that, across many types of direct collision, independent of the inclination or offset, the distributions of weighted Mach numbers and shock velocities in colliding clouds relax to a very similar form. There is good evidence of prolonged turbulence in the gas of each splash bridge for all inclinations and offsets tested, as a result of continuing cloud collisions, which in turn are the result of shearing and differentially accelerated trajectories. The number distribution of high velocity shocks in cloud collisions, produced in our low inclination models, are in agreement with those observed in the Taffy Galaxies with ALMA, Appleton et al., 2019.

[21]  arXiv:2001.03816 [pdf]

Title: Source of Energetic Protons in the 2014 September 1 Sustained Gamma-ray Emission Event

Authors: N. Gopalswamy, P. Mäkelä, S. Yashiro, H. Xie, S. Akiyama, N. Thakur

Comments: 39 pages, 14 figures, to appear in Solar Physics

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

We report on the source of greater than 300 MeV protons during the SOL2014-09-01 sustained gamma-ray emission (SGRE) event based on multi-wavelength data from a wide array of space- and ground-based instruments. Based on the eruption geometry we provide concrete explanation for the spatially and temporally extended {\gamma}-ray emission from the eruption. We show that the associated flux rope is of low inclination (roughly oriented in the east-west direction), which enables the associated shock to extend to the frontside. We compare the centroid of the SGRE source with the location of the flux rope leg to infer that the high-energy protons must be precipitating between the flux rope leg and the shock front. The durations of the SOL2014-09-01 SGRE event and the type II radio burst agree with the linear relationship between these parameters obtained for other SGRE events with duration exceeding 3 hrs. The fluence spectrum of the SEP event is very hard, indicating the presence of high-energy (GeV) particles in this event. This is further confirmed by the presence of an energetic coronal mass ejection (CME) with a speed more than 2000 km/s, similar to those in ground level enhancement (GLE) events. The type II radio burst had emission components from metric to kilometric wavelengths as in events associated with GLE events. All these factors indicate that the high-energy particles from the shock were in sufficient numbers needed for the production of {\gamma}-rays via neutral pion decay.

[22]  arXiv:2001.03833 [pdf, other]

Title: The merger history of primordial-black-hole binaries

Authors: You Wu

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

As a candidate of dark matter, primordial black holes (PBHs) have attracted more and more attentions as they could be possible progenitors of the heavy binary black holes (BBHs) observed by LIGO/Virgo. Accurately estimating the merger rate of PBH binaries will be crucial to reconstruct the mass distribution of PBHs. It was pointed out the merger history of PBHs may shift the merger rate distribution depending on the mass function of PBHs. In this paper, we use 10 BBH events from LIGO/Virgo O1 and O2 observing runs to constrain the merger rate distribution of PBHs by accounting the effect of merger history. It is found that the second merger process makes subdominant contribution to the total merger rate, and hence the merger history effect can be safely neglected.

[23]  arXiv:2001.03840 [pdf]

Title: Strain Mapping by Digital laser Speckle Correlation, Validation and Comparison

Authors: Mahshad Mosayebi

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

This Paper introduces a new Non-Contact, Optical method for displacement measurements, and strain mapping as well as comparing it to traditional Digital Image correlation (DIC) and laser interferometry measurement method. This Method incorporates diffracted laser speckle images from the surfaces through DIC to track displacement and locate strain values. In order to evaluate the feasibility of the method, various experiments were done and results were compared to laser interferometry based and traditional DIC. All the experiments were designed and done with affordable equipment, while they resulted in displacement as small as 30 micro-meter detection. Results presented by this paper are showing that DilSIC is an economic, accurate, rapid and applicable method for the mentioned purpose. Since it does not require any artifact speckle pattern, it can be used on the non-accessible area, limits and difficulties for creating speckle pattern is not applicable for this technique. In this research, various magnitude of strains have been examined within the range of [0-10%]. As this technique is a hybrid method of DIC and Laser speckle measurement it could eliminate some of the limits that everyone has. Those removed restrictions include but not limited to being able to measure strain within range of [0-10%] while using fringes on laser speckle does not let the measurement exceed 2%. Also using laser speckle pattern can end all the challenges to achieve the qualified speckle pattern as they can be adjusted to match the requirement easily.

[24]  arXiv:2001.03850 [pdf, other]

Title: Solar Image Deconvolution by Generative Adversarial Network

Authors: Long Xu, Wenqing Sun, Yihua Yan, Weiqiang Zhang

Comments: 14 pages, 6 figures, 2 tables

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Image and Video Processing (eess.IV)

With Aperture synthesis (AS) technique, a number of small antennas can assemble to form a large telescope which spatial resolution is determined by the distance of two farthest antennas instead of the diameter of a single-dish antenna. Different from direct imaging system, an AS telescope captures the Fourier coefficients of a spatial object, and then implement inverse Fourier transform to reconstruct the spatial image. Due to the limited number of antennas, the Fourier coefficients are extremely sparse in practice, resulting in a very blurry image. To remove/reduce blur, "CLEAN" deconvolution was widely used in the literature. However, it was initially designed for point source. For extended source, like the sun, its efficiency is unsatisfied. In this study, a deep neural network, referring to Generative Adversarial Network (GAN), is proposed for solar image deconvolution. The experimental results demonstrate that the proposed model is markedly better than traditional CLEAN on solar images.

[25]  arXiv:2001.03866 [pdf, other]

Title: The LOFAR Tied-Array All-Sky Survey: Timing of 21 pulsars including the first binary pulsar discovered with LOFAR

Authors: C. M. Tan, C. G. Bassa, S. Cooper, J. W. T. Hessels, V. I. Kondratiev, D. Michilli, S. Sanidas, B. W. Stappers, J. van Leeuwen, J. Y. Donner, J.-M. Grießmeier, M. Kramer, C. Tiburzi, P. Weltevrede, B. Ciardi, M. Hoeft, G. Mann, A. Miskolczi, D. J. Schwarz, C. Vocks, O. Wucknitz

Comments: 21 pages, 12 figures, Accepted for publication in the Monthly Notices of the Royal Astronomical Society

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We report on the multi-frequency timing observations of 21 pulsars discovered in the LOFAR Tied-Array All-Sky Survey (LOTAAS). The timing data were taken at central frequencies of 149 MHz (LOFAR) as well as 334 and 1532 MHz (Lovell Telecope). The sample of pulsars includes 20 isolated pulsars and the first binary pulsar discovered by the survey, PSR J1658$+$3630. We modelled the timing properties of the pulsars, which showed that they have, on average, larger characteristic ages. We present the pulse profiles of the pulsars across the three observing bands, where PSR J1643$+$1338 showed profile evolution that appears not to be well-described by the radius-to-frequency-mapping model. Furthermore, we modelled the spectra of the pulsars across the same observing bands, using a simple power law, and found an average spectral index of $-1.9 \pm 0.5$. Amongst the pulsars studied here, PSR J1657$+$3304 showed large flux density variations of a factor of 10 over 300 days, as well as mode changing and nulling on timescales of a few minutes. We modelled the rotational and orbital properties of PSR J1658$+$3630, which has a spin period of 33 ms in a binary orbit of 3.0 days with a companion of minimum mass of 0.87$M_{\odot}$, likely a Carbon-Oxygen or Oxygen-Neon-Magnesium type white dwarf. PSR J1658$+$3630 has a dispersion measure of 3.0 pc cm$^{-3}$, making it possibly one of the closest binary pulsars known.

[26]  arXiv:2001.03874 [pdf, other]

Title: Exploiting solar visible-range observations by inversion techniques: from flows in the solar subsurface to a flaring atmosphere

Authors: Michal Švanda (1 and 2), Jan Jurčák (2), David Korda (1), Jana Kašparová (2) ((1) Astronomical Institute, Charles University, Prague, Czech Republic (2) Astronomical Institute, Academy of Sciences of the Czech Republic, Ondrejov, Czech Republic)

Comments: 29 pages, 15 figures. Accepted for publication in the book "Reviews in Frontiers of Modern Astrophysics: From Space Debris to Cosmology" (eds Kabath, Jones and Skarka; publisher Springer Nature) funded by the European Union Erasmus+ Strategic Partnership grant "Per Aspera Ad Astra Simul" 2017-1-CZ01-KA203-035562

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Observations of the Sun in the visible spectral range belong to standard measurements obtained by instruments both on the ground and in the space. Nowadays, both nearly continuous full-disc observations with medium resolution and dedicated campaigns of high spatial, spectral and/or temporal resolution constitute a holy grail for studies that can capture (both) the long- and short-term changes in the dynamics and energetics of the solar atmosphere. Observations of photospheric spectral lines allow us to estimate not only the intensity at small regions, but also various derived data products, such as the Doppler velocity and/or the components of the magnetic field vector. We show that these measurements contain not only direct information about the dynamics of solar plasmas at the surface of the Sun but also imprints of regions below and above it. Here, we discuss two examples: First, the local time-distance helioseismology as a tool for plasma dynamic diagnostics in the near subsurface and second, the determination of the solar atmosphere structure during flares. The methodology in both cases involves the technique of inverse modelling.

[27]  arXiv:2001.03876 [pdf, ps, other]

Title: Unified equations of state for cold non-accreting neutron stars with Brussels-Montreal functionals. II. Pasta phases in semi-classical approximation

Authors: J. M. Pearson, N. Chamel, A. Y. Potekhin

Comments: 16 pages, 14 tables, 8 figures, accepted by Phys. Rev. C

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)

We generalize our earlier work on neutron stars (arXiv:1903.04981), which assumed spherical Wigner-Seitz cells in the inner crust, to admit the possibility of pasta phases, i.e., non-spherical cell shapes. Full fourth-order extended Thomas-Fermi calculations using the density functional BSk24 are performed for cylindrical and plate-like cells. Unlike in our spherical-cell calculations, we do not include shell and pairing corrections, but there are grounds for expecting these corrections for pasta to be significantly smaller. It is therefore meaningful to compare the ETF pasta results with the full spherical-cell results, i.e., with shell and pairing corrections included. However, in view of the many previous studies in which shell and pairing corrections were omitted entirely, it is of interest to compare our pasta results with the ETF part of the corresponding spherical calculations. Making this latter comparison we find that as the density increases the cell shapes pass through the usual sequence sphere $\to$ cylinder $\to$ plate before the transition to the homogeneous core. The filling fractions found at the phase transitions are in close agreement with expectations based on the liquid-drop model. On the other hand, when we compare with the full spherical-cell results, we find the sequence to be sphere $\to$ cylinder $\to$ sphere $\to$ cylinder $\to$ plate. In neither case do any "inverted", i.e., bubble-like, configurations appear. We provide accurate fitting formulas to all our essential numerical results for each of the three phases, designed especially for the density range where the nonspherical shapes are expected, which enable one to capture not only the general behavior of the fitted functions, but also the differences between them in different phases.

[28]  arXiv:2001.03879 [pdf, other]

Title: Cosmological Collider Signatures of Massive Vectors from Non-Gaussian Gravitational Waves

Authors: Yi Wang, Yuhang Zhu

Comments: 14 pages, 3 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)

The cosmological collider provides a model-independent probe of particle physics during inflation. We extend the study of cosmological collider physics to much smaller scales through gravitational wave (GW) probes. With a Chern-Simons interaction, a massive vector field can obtain a chemical potential and its particle production can cause significant non-Gaussian GW signals. We calculate the mass and spin dependences of the induced GW 3-point correlation function in the squeezed limit, and estimate its amplitude. Such signals may be detectable in the current and upcoming GW interferometer experiments.

[29]  arXiv:2001.03912 [pdf, ps, other]

Title: Perturbations dynamics in Keplerian flow under external stochastic forcing

Authors: D. N. Razdoburdin

Comments: Accepted for publication in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Fluid Dynamics (physics.flu-dyn)

We investigate the dynamics of linear perturbations in Keplerian flow under external stochastic force. To abstract from the details of flow structure and boundary conditions, we consider the problem in the shearing box approximation. An external force is assumed to have zero mean, even so, induced perturbations form a steady-state, which provides angular momentum transfer to the periphery of the flow. The most effective scenario is based on the transient amplification of induced vortices with the following emission of shearing sound wave, wherein the maximum of the flux linearly depends on Reynolds number. Thus such a mechanism is significant for astrophysical flows, for which enormous Reynolds numbers are typical. At the same time, addressing the problem analytically, we found that for incompressible fluid in the shearing box approximation stochastic forcing does not lead to average angular momentum transfer. Thus the compressibility of the fluid plays an important role here, and one cannot neglect it.

[30]  arXiv:2001.03949 [pdf, other]

Title: Dispersal of protoplanetary disks by the combination of magnetically driven and photoevaporative winds

Authors: Masanobu Kunitomo, Takeru K. Suzuki, Shu-ichiro Inutsuka

Comments: Accepted for publicatoin in MNRAS. 11 pages, 6 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

We investigate the roles of magnetically driven disk wind (MDW) and thermally driven photoevaporative wind (PEW) in the long-time evolution of protoplanetary disks. We start simulations from the early phase in which the disk mass is $0.118\,{\mathrm{M}_{\odot}}$ around a $1\,{\mathrm{M}_{\odot}}$ star and track the evolution until the disk is completely dispersed. We incorporate the mass loss by PEW and the mass loss and magnetic braking (wind torque) by MDW, in addition to the viscous accretion, viscous heating, and stellar irradiation. We find that MDW and PEW respectively have different roles: magnetically driven wind ejects materials from an inner disk in the early phase, whereas photoevaporation has a dominant role in the late phase in the outer ($\gtrsim1\,$au) disk. The disk lifetime, which depends on the combination of MDW, PEW, and viscous accretion, shows a large variation of $\sim1$-$20\,$Myr; the gas is dispersed mainly by the MDW and the PEW in the cases with a low viscosity and the lifetime is sensitive to the mass-loss rate and torque of the MDW, whereas the lifetime is insensitive to these parameters when the viscosity is high. Even in disks with very weak turbulence, the cooperation of MDW and PEW enables the disk dispersal within a few Myr.

[31]  arXiv:2001.03978 [pdf]

Title: Nonequilibrium Layer in the Crust of Neutron Stars and Nonequilibrium Beta-Processes in Astrophysics

Authors: G. S. Bisnovatyi-Kogan

Comments: JETP 2019, V.129, p. 503. Special issue in honor of I.M. Khalatnikov 100th anniversary

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

The formation of the chemical composition of neutron star envelopes, at high densities is considered. As hot matter is compressed in the process of collapse, which leads to the explosion of a core collapse supernova, the stage of nuclear equilibrium with free neutrino escape, kinetic equilibrium in \b{eta}-processes, and, as a result, the establishment of limited nuclear equilibrium with a fixed number of nuclei takes place. Cold matter is compressed at a fixed number of nuclei whose atomic weight initially does not change and subsequently decreases. A pycnonuclear reaction of the fusion of available nuclei and a decrease in their number begin at the end. The compression of cold matter is accompanied by an increase in the mass fraction of free neutrons. In this case, the chemical composition of the envelope differs significantly from the equilibrium one and contains a considerable store of nuclear energy. Nonequilibrium \b{eta}-reactions proceed at densities exceeding the upper bound for the non-equilibrium layer density, which lead to heating, nuclear energy release, and the possible attainment of a state of complete thermodynamic equilibrium. The thermodynamics of nonequilibrium \b{eta}-processes, which lead to the heating of matter as neutrinos escape freely, is considered.

[32]  arXiv:2001.03979 [pdf, other]

Title: A broadband X-ray view of the NLSy1 1E 0754.6+392.8

Authors: R. Middei, F. Tombesi, F. Vagnetti, R. Serafinelli, S. Bianchi, G. Miniutti, A. Marinucci, G. A. Matzeu, P.-O. Petrucci, F. Ursini, A. Zaino

Comments: Accepted for publication in A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

The soft X-ray band of many active galactic nuclei (AGNs) is affected by obscuration due to partially ionised matter crossing our line of sight. In this context, two past XMM-Newton observations (6 months apart) and a simultaneous NuSTAR-Swift ($\sim$8 years later) exposure of the Narrow Line Seyfert 1 galaxy 1E 0754.6+392.8 revealed an intense and variable WA and hints of additional absorbers in the Fe K$\alpha$ band. We present the first X-ray characterisation of this AGN discussing its broadband (0.3-79 keV) spectrum and temporal properties. We conduct a temporal and spectroscopic analysis on two $\sim$10 ks (net exposure) XMM-Newton snapshots performed in April and October 2006. We also study the high energy behaviour of 1E 0754.6+392.8 modelling its broadband spectrum using simultaneous Swift-NuSTAR data. Both phenomenological and physically motivated models are tested. We find the presence of flux variability ($\sim$150% and 30% for 0.3-2 and 2-10 keV bands, respectively) and spectral changes at months timescales ($\Delta\Gamma\sim$0.4). A reflection component that is consistent with being constant over years and arising from relatively cold material far from the central super massive black hole is detected. The main spectral feature shaping the 1E 0754.6+392.8 spectrum is a warm absorber. Such a component is persistent over the years and variability of its ionisation and column density is observed down on months in the ranges 3$\times10^{22} \rm cm^{-2}\lesssim$ N$_{\rm{H}}\lesssim7.2\times10^{22} \rm cm^{-2}$ and 1.5 $\lesssim\log(\xi/{\rm erg~s^{-1}~cm})\lesssim$2.1. Despite the short exposures, we find possible evidence of two additional highly ionised and high-velocity outflow components in absorption. Longer exposures are mandatory in order to characterise the complex outflow in this AGN.

[33]  arXiv:2001.03987 [pdf, other]

Title: Calibration of ground based survey data using Gaia: Application to DES

Authors: Koshy George, Thomas Vassallo, Joseph Mohr, Mohammad Mirkazemi, Holger Israel, Jelte T. A. de Jong, Gijs A. Verdoes Kleijn

Comments: To appear in proceedings of ADASS XXIX, ASP Conf. Series

Subjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)

The calibration of ground based optical imaging data to photometric accuracy of 10 mmag over the full survey area and to color uniformity better than 5 mmag on the scale of the VIS focal plane is a key science requirement for the Euclid mission. These accuracies enable stable photometric redshifts of galaxies and modeling of the color dependent VIS PSF for weak lensing studies. We use the Gaia photometry to calibrate the $g/r/i/z$ magnitudes of Dark Energy Survey (DES) data to meet the stringent Euclid requirements. The Gaia G band magnitude along with the BP-RP color information of stars observed in the DES single epoch (SE) exposures are used to derive the transformation from Gaia to DES photometry for individual CCDs and to characterize persistent photometric errors across the DECam focal plane. We use the color dependence of these persistent errors to characterize the $g/r/i/z$ bandpass variations across the DECam focal plane.

[34]  arXiv:2001.03995 [pdf, other]

Title: CMB Cold Spot in the Planck light

Authors: M. Farhang, S. M. S. Movahed

Comments: 5 pages, 4 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

The Cold Spot is a statistically significant anomaly in the Cosmic Microwave Background (CMB) sky. In this work we assess whether a huge void or a cosmic texture could have produced such an anomaly through searching for their gravitational redshift (Rees-Sciama effect) and lensing signatures on the {\it Planck} CMB sky. In the flat sky approximation, we find the amplitudes for the corresponding templates for both candidates consistent with zero, leaving little room, according to {\it Planck}, for those structures as the main source of the Cold Spot anomaly.

[35]  arXiv:2001.04037 [pdf, other]

Title: xGASS: Robust quantification of asymmetries in global HI spectra and their relationship to environmental processes

Authors: Adam B. Watts, Barbara Catinella, Luca Cortese, Chris Power

Comments: 14 pages, 16 figures, accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present an analysis of asymmetries in global HI spectra from the extended GALEX Arecibo SDSS Survey (xGASS), a stellar mass-selected and gas fraction-limited survey which is representative of the HI properties of galaxies in the local Universe. We demonstrate that the asymmetry in a HI spectrum is strongly linked to its signal-to-noise meaning that, contrary to what was done in previous works, asymmetry distributions for different samples cannot be compared at face value. We develop a method to account for noise-induced asymmetry and find that the typical galaxy detected by xGASS exhibits higher asymmetry than what can be attributed to noise alone, with 37% of the sample showing asymmetry greater than 10% at an 80% confidence level. We find that asymmetric galaxies contain, on average, 29% less HI mass compared to their symmetric counterparts matched in both stellar mass and signal-to-noise. We also present clear evidence that satellite galaxies, as a population, exhibit more asymmetric HI spectra than centrals and that group central galaxies show a slightly higher rate of HI asymmetries compared to isolated centrals. All these results support a scenario in which environmental processes, in particular those responsible for gas removal, are the dominant driver of asymmetry in xGASS.

[36]  arXiv:2001.04043 [pdf, ps, other]

Title: Magnetic Gradient: A Natural Driver of Solar Eruptions

Authors: Baolin Tan, Yan Yan, Ting Li, Yin Zhang, Xingyao Chen

Comments: 16 pages, 7 figures, 2 tables, accepted by RAA

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

It is well-known that there is a gradient, there will drive a flow inevitably. For example, a density-gradient may drive a diffusion flow, an electrical potential-gradient may drive an electric current in plasmas, etc. Then, what will be driven when a magnetic-gradient occurs in solar atmospheric plasmas? Considering the ubiquitous distribution of magnetic-gradient in solar plasma loops, this work demonstrates that magnetic-gradient pumping (MGP) mechanism is valid even in the partial ionized solar photosphere, chromosphere as well as in the corona. It drives energetic particle flows which carry and convey kinetic energy from the underlying atmosphere to move upwards, accumulate around the looptop and increase there temperature and pressure, and finally lead to eruptions around the looptop by triggering ballooning instabilities. This mechanism may explain the formation of the observing hot cusp-structures above flaring loops in most preflare phases, therefore, the magnetic-gradient should be a natural driver of solar eruptions. Furthermore, we may also apply to understand many other astrophysical phenomena, such as the temperature distribution above sunspots, the formation of solar plasma jets, type-II spicule, and fast solar wind above coronal holes, as well as the fast plasma jets related to white dwarfs, neutron stars and black holes.

[37]  arXiv:2001.04046 [pdf, other]

Title: First demonstration of OH suppression in a high efficiency near-infrared spectrograph

Authors: S.C. Ellis (1,2), J. Bland-Hawthorn (2,3), J.S. Lawrence (1), A.J. Horton (1), R. Content (1), M.M. Roth (4), N. Pai (1), R. Zhelem (1), S. Case (1), E. Hernandez (4), S.G. Leon-Saval (2,3), R. Haynes (5), S.S. Min (3), D. Giannone (4), K. Madhav (4), A. Rahman (4), C. Betters (3), D. Haynes (5), W. Couch (1), L.J. Kewley (5), R. McDermid (6), L. Spitler (6), R.G. Sharp (5), S. Veilleux (7,8) ((1) Australian Astronomical Optics (AAO), Macquarie University, (2) Sydney Institute for Astronomy, University of Sydney, (3) Sydney Astrophotonic Instrumentation Labs, University of Sydney, (4) Leibniz-Institut für Astrophysik Potsdam, (5) Research School of Astronomy and Astrophysics, Australian National University, (6) Department of Physics and Astronomy, Macquarie University, (7) Department of Astronomy, University of Maryland, (8) Joint Space-Science Institute, University of Maryland)

Comments: Accepted for publication in MNRAS

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

Ground-based near-infrared astronomy is severely hampered by the forest of atmospheric emission lines resulting from the rovibrational decay of OH molecules in the upper atmosphere. The extreme brightness of these lines, as well as their spatial and temporal variability, makes accurate sky subtraction difficult. Selectively filtering these lines with OH suppression instruments has been a long standing goal for near-infrared spectroscopy. We have shown previously the efficacy of fibre Bragg gratings combined with photonic lanterns for achieving OH suppression. Here we report on PRAXIS, a unique near-infrared spectrograph that is optimised for OH suppression with fibre Bragg gratings. We show for the first time that OH suppression (of any kind) is possible with high overall throughput (18 per cent end-to-end), and provide examples of the relative benefits of OH suppression.

[38]  arXiv:2001.04065 [pdf, other]

Title: Constraints on the Emission of Gamma Rays from M31 with HAWC

Authors: HAWC Collaboration: A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, H. A. Ayala Solares, E. Belmont-Moreno, S. Y. BenZvi, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, S. Dichiara, B. L. Dingus, M. A. DuVernois, K. Engel, C. Espinoza, H. Fleischhack, N. Fraija, A. Galván-Gámez, D. García-Aguilar, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, J. P. Harding, S. Hernandez, B. Hona, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, A. Jardin-Blicq, V. Joshi, D. Kieda, W. H. Lee, H. León Vargas, A. L. Longinotti, G. Luis-Raya, K. Malone, S. S. Marinelli, et al. (36 additional authors not shown)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Cosmic rays, along with stellar radiation and magnetic fields, are known to make up a significant fraction of the energy density of galaxies such as the Milky Way. When cosmic rays interact in the interstellar medium, they produce gamma-ray emission which provides an important indication of how the cosmic rays propagate. Gamma rays from the Andromeda Galaxy (M31), located 785 kpc away, provide a unique opportunity to study cosmic-ray acceleration and diffusion in a galaxy with a structure and evolution very similar to the Milky Way. Using 33 months of data from the High Altitude Water Cherenkov Observatory, we search for TeV gamma rays from the galactic plane of M31. We also investigate past and present evidence of galactic activity in M31 by searching for Fermi Bubble-like structures above and below the galactic nucleus. No significant gamma-ray emission is observed, so we use the null result to compute upper limits on the energy density of cosmic rays $>10$ TeV in M31. The computed upper limits are approximately ten times higher than expected from the extrapolation of the Fermi LAT results.

[39]  arXiv:2001.04068 [pdf, ps, other]

Title: Photometric, kinematic and variability study in the young open cluster NGC 1960

Authors: Yogesh C. Joshi, Jayanand Maurya, Ancy Anna John, Alaxender Panchal, Santosh Joshi, Brijesh Kumar

Comments: Accepted for publication on December 20, 2019 in MNRAS. 20 pages, 15 figures, 12 tables

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

We present a comprehensive photometric analysis of a young open cluster NGC 1960 (M36) along with the long-term variability study of this cluster. Based on the kinematic data of Gaia DR2, the membership probabilities of 3871 stars are ascertained in the cluster field among which 262 stars are found to be cluster members. Considering the kinematic and trigonometric measurements of the cluster members, we estimate a mean cluster parallax of 0.86+/-0.05 mas and mean proper motions of mu_RA = -0.143+/-0.008 mas/yr, mu_Dec = -3.395+/-0.008 mas/yr. We obtain basic parameters of the cluster such as E(B-V) = 0.24+/-0.02 mag, log(Age/yr)=7.44+/-0.02, and distance = 1.17+/-0.06 kpc. The mass function slope in the cluster for the stars in the mass range of 0.72-7.32 M_solar is found to be \gamma = -1.26+/-0.19. We find that mass segregation is still taking place in the cluster which is yet to be dynamically relaxed. This work also presents first high-precision variability survey in the central 13'x13' among which 72 are periodic variables. Among them, 59 are short-period (P<1 day)and 13 are long-period (P>1 day). The variable stars have V magnitudes ranging between 9.1 to 19.4 mag and periods between 41 minutes to 10.74 days. On the basis of their locations in the H-R diagram, periods and characteristic light curves, the 20 periodic variables belong to the cluster. We classified them as 2 delta-Scuti, 3 gamma-Dor, 2 slowly pulsating B stars, 5 rotational variables, 2 non-pulsating B stars and 6 as miscellaneous variables.

[40]  arXiv:2001.04075 [pdf, ps, other]

Title: APEX observations of ortho-H$_2$D$^+$ towards dense cores in the Orion B9 filament

Authors: Oskari Miettinen (Academy of Finland)

Comments: 15 pages (incl. an appendix), 8 figures, 7 tables, accepted for publication in A&A, abstract abridged for arXiv

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We used the APEX telescope to observe the 372 GHz o-H$_2$D$^+(J_{K_a,\,K_c}=1_{1,\,0}-1_{1,\,1})$ line towards three prestellar cores and three protostellar cores in Orion B9. We also employed our previous APEX observations of C$^{17}$O, C$^{18}$O, N$_2$H$^+$, and N$_2$D$^+$ line emission, and 870 $\mu$m dust continuum emission towards the target sources. The o-H$_2$D$^+$ line was detected in all three prestellar cores, but in only one of the protostellar cores. The corresponding o-H$_2$D$^+$ abundances were derived to be $\sim(12-30)\times10^{-11}$ and $6\times10^{-11}$. Two additional spectral lines, DCO$^+(5-4)$ and N$_2$H$^+(4-3)$, were detected in the observed frequency bands with high detection rates of $100\%$ and $83\%$, respectively. The Orion B9 cores were found to be consistent with the relationship between the o-H$_2$D$^+$ abundance and gas temperature obeyed by other low-mass dense cores. The o-H$_2$D$^+$ abundance was found to decrease as the core evolves. The o-H$_2$D$^+$ abundances in the Orion B9 cores are in line with those found in other low-mass cores and larger than derived for high-mass star-forming regions. The higher o-H$_2$D$^+$ abundance in prestellar cores compared to that in cores hosting protostars is to be expected from chemical reactions where higher concentrations of gas-phase CO and elevated gas temperature accelerate the destruction of H$_2$D$^+$. The validity of using the [o-H$_2$D$^+$]/[N$_2$D$^+$] ratio as an evolutionary indicator, which has been proposed for massive clumps, remains to be determined when applied to these target cores. Overall, as located in a dynamic environment of Orion B, the Orion B9 filament provides an interesting target system to investigate the deuterium-based chemistry, and further observations of species like para-H$_2$D$^+$ and D$_2$H$^+$ would be of particular interest.

[41]  arXiv:2001.04081 [pdf, other]

Title: An investigation on the factors affecting machine learning classifications in $γ$-ray astronomy

Authors: Shengda Luo (1), Alex P. Leung (1), C. Y. Hui (2), K.L. Li (2,3,4) ((1) Macau University of Science and Technology, (2) Chungnam National University, (3) UNIST, (4) National Tsing Hua University)

Comments: 15 pages, 10 figures, 11 tables, accepted for publication in MNRAS

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)

We have investigated a number of factors that can have significant impacts on the classification performance of $\gamma$-ray sources detected by Fermi Large Area Telescope (LAT) with machine learning techniques. We show that a framework of automatic feature selection can construct a simple model with a small set of features which yields better performance over previous results. Secondly, because of the small sample size of the training/test sets of certain classes in $\gamma$-ray, nested re-sampling and cross-validations are suggested for quantifying the statistical fluctuations of the quoted accuracy. We have also constructed a test set by cross-matching the identified active galactic nuclei (AGNs) and the pulsars (PSRs) in the Fermi LAT eight-year point source catalog (4FGL) with those unidentified sources in the previous 3$^{\rm rd}$ Fermi LAT Source Catalog (3FGL). Using this cross-matched set, we show that some features used for building classification model with the identified source can suffer from the problem of covariate shift, which can be a result of various observational effects. This can possibly hamper the actual performance when one applies such model in classifying unidentified sources. Using our framework, both AGN/PSR and young pulsar (YNG)/millisecond pulsar (MSP) classifiers are automatically updated with the new features and the enlarged training samples in 4FGL catalog incorporated. Using a two-layer model with these updated classifiers, we have selected 20 promising MSP candidates with confidence scores $>98\%$ from the unidentified sources in 4FGL catalog which can provide inputs for a multi-wavelength identification campaign.

[42]  arXiv:2001.04090 [pdf, other]

Title: The Formation History of Subhalos and the Evolution of Satellite Galaxies

Authors: Jingjing Shi, Huiyuan Wang, Houjun Mo, Mark Vogelsberger, Luis C. Ho, Min Du, Dylan Nelson, Annalisa Pillepich, Lars Hernquist

Comments: 21 pages, 10 figures, submitted to ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Satellites constitute an important fraction of the overall galaxy population and are believed to form in dark matter subhalos. Here we use the cosmological hydrodynamic simulation TNG100 to investigate how the formation histories of subhalos affect the properties and evolution of their host galaxies. We use a scaled formation time ($a_{\rm nf}$) to characterize the mass assembly histories of the subhalos before they are accreted by massive host halos. We find that satellite galaxies in young subhalos (low $a_{\rm nf}$) are less massive and more gas rich, and have stronger star formation and a higher fraction of ex situ stellar mass than satellites in old subhalos (high $a_{\rm nf}$). Furthermore, these low $a_{\rm nf}$ satellites require longer timescales to be quenched as a population than the high $a_{\rm nf}$ counterparts. We find very different merger histories between satellites in fast accretion (FA, $a_{\rm nf}<1.3$) and slow accretion (SA, $a_{\rm nf}>1.3$) subhalos. For FA satellites, the galaxy merger frequency dramatically increases just after accretion, which enhances the star formation at accretion. While, for SA satellites, the mergers occur smoothly and continuously across the accretion time. Moreover, mergers with FA satellites happen mainly after accretion, while a contrary trend is found for SA satellites. Our results provide insight into the evolution and star formation quenching of the satellite population.

[43]  arXiv:2001.04094 [pdf]

Title: Virial models and Anisotropy of Velocity Dispersion in e-galaxies

Authors: B. P. Kondratyev, E. N. Kireeva

Comments: 10 pages, 5 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

A tensor virial approach is used to construct detailed models of 22 flattened ellipticals. The models are combined with the new observational data: extended surface brightness distributions, the profiles of isophotes flattening and their twisting, the rotation curves and the velocity dispersion profiles. A key feature of these models is a rigorous consideration of the influence of the spatial shape of galaxies (oblate spheroid or triaxial ellipsoid) on the dynamics, as well as the structure of the internal density layers in these systems. For each galaxy the ratio of the rotational energy to the potential energy was found. Comparing this ratio with the observed it is concluded that the majority of these systems cannot have isotropic velocity dispersion tensors. The anisotropy parameter limited to the interval 0.0-0.224. A correlation was found between and flattening of the outer regions for giant E-galaxies. Our results are compared with the results of other researchers. It was found that for small fast rotators our values \b{eta} are in good agreement with those, obtained in the ATLAS project. However, for giant E-galaxies, our models provide better agreement with observations, than axisymmetric JAM models. In addition, our velocity dispersion anisotropy results are in satisfactory agreement with the results of high resolution cosmological simulations in the Illustris project

[44]  arXiv:2001.04145 [pdf, ps, other]

Title: Photometric characterization of multiple populations in star clusters: The impact of the first dredge-up

Authors: Maurizio Salaris (1), Chris Usher (1), Silvia Martocchia (1,2), Emanuele Dalessandro (3), Nate Bastian (1), Sara Saracino (1), Santi Cassisi (4,5) Ivan Cabrera-Ziri (6), Carmela Lardo (7) (1, Astrophysics Research Institute, Liverpool John Moores University, UK - 2, European Southern Observatory, D - 3, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, I - 4, INAF-Osservatorio Astronomico d'Abruzzo, I - 5, INFN - Sezione di Pisa, I - 6, Harvard-Smithsonian Center for Astrophysics, USA - 7, EPFL, Versoix, CH)

Comments: 7 pages, 6 figures, MNRAS in press

Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

The existence of star-to-star light-element abundance variations (multiple populations, MPs) in massive Galactic and extragalactic star clusters older than about 2 Gyr is by now well established. Photometry of red giant branch (RGB) stars has been and still is instrumental in enabling the detection and characterization of cluster MPs, through the appropriate choices of filters, colours and colour combinations, that are mainly sensitive to N and --to a lesser degree-- C stellar surface abundances. An important issue not yet properly addressed is that the translation of the observed widths of the cluster RGBs to abundance spreads must account for the effect of the first dredge-up on the surface chemical patterns, hence on the spectral energy distributions of stars belonging to the various MPs. We have filled this gap by studying theoretically the impact of the dredge-up on the predicted widths of RGBs in clusters hosting MPs. We find that for a given initial range of N abundances, the first dredge up reduces the predicted RGB widths in N-sensitive filters compared to the case when its effect on the stellar spectral energy distributions is not accounted for. This reduction is a strong function of age and has also a dependence on metallicity. The net effect is an underestimate of the initial N-abundance ranges from RGB photometry if the first dredge-up is not accounted for in the modelling, and also the potential determination of spurious trends of N-abundance spreads with age.

[45]  arXiv:2001.04172 [pdf, other]

Title: Ionization and dissociation induced fragmentation of a tidally disrupted star into planets around a supermassive black hole

Authors: Kimitake Hayasaki, Matthew R. Bate, Abraham Loeb

Comments: 13 pages, 4 figures, submitted for publication, comments welcome

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

We show results from the radiation hydrodynamics (RHD) simulations of tidal disruption of a star on a parabolic orbit by a supermassive black hole (SMBH) based on a three-dimensional smoothed particle hydrodynamics code with radiative transfer. We find that such a tidally disrupted star fragment and form clumps soon after its tidal disruption. The fragmentation results from the endothermic processes of ionization and dissociation that reduce the gas pressure, leading to local gravitational collapse. Radiative cooling is less effective because the stellar debris is still highly optically thick in such an early time. Our simulations reveal that a solar-type star with a stellar density profile of n=3 disrupted by a 10^6 solar mass black hole produces $\sim20$ clumps of masses in the range of 0.1 to 12 Jupiter masses. The mass fallback rate decays with time, with pronounced spikes from early to late time. The spikes provide evidence for the clumps of the returning debris, while the clumps on the unbound debris can be potentially freely-floating planets and brown dwarfs. This ionization and dissociation induced fragmentation on a tidally disrupted star are a promising candidate mechanism to form low-mass stars to planets around an SMBH.

[46]  arXiv:2001.04176 [pdf, other]

Title: A search for Centaurus A-like features in the spectra of Fermi-LAT detected radio galaxies

Authors: Cameron B. Rulten (1), Anthony M. Brown (1), Paula M. Chadwick (1) ((1) Durham University)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Motivated by the detection of a hardening in the gamma-ray spectrum of the radio galaxy Centaurus A, we have analysed ~10 years of Fermi-LAT observations of 26 radio galaxies to search for similar spectral features. We find that the majority of the radio galaxies' gamma-ray spectral energy distributions are best fitted with a simple power-law model, and no spectral hardening similar to that found in Centaurus A was detected. We show that, had there been any such spectral features present in our sample of radio galaxies, they would have been seen, but note that 7 of the radio galaxies (3C 111, 3C 120, 3C 264, IC 4516, NGC 1218, NGC 2892 and PKS 0625-35) show evidence for flux variability on 6-month timescales, which makes the detection of any steady spectral features difficult. We find a strong positive correlation (r = 0.9) between the core radio power at 5 GHz and the gamma-ray luminosity and, using a simple extrapolation to TeV energies, we expect around half of the radio galaxies studied will be detectable with the forthcoming Cherenkov Telescope Array.

[47]  arXiv:2001.04177 [pdf, other]

Title: Identifying Earth-impacting asteroids using an artificial neural network

Authors: John D. Hefele, Francesco Bortolussi, Simon Portegies Zwart

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

By means of a fully connected artificial neural network, we identified asteroids with the potential to impact Earth. The resulting instrument, named the Hazardous Object Identifier (HOI), was trained on the basis of an artificial set of known impactors which were generated by launching objects from Earth's surface and integrating them backward in time. HOI was able to identify 95.25% of the known impactors simulated that were present in the test set as potential impactors. In addition, HOI was able to identify 90.99% of the potentially hazardous objects identified by NASA, without being trained on them directly.

[48]  arXiv:2001.04178 [pdf, other]

Title: Probing core overshooting using asteroseismology

Authors: S. Deheuvels

Comments: To appear in the proceedings of the workshop "How Much do we Trust Stellar Models?" held in Li\`ege in September 2018

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Modeling properly the interface between convective cores and radiative interiors is one the most challenging and important open questions in modern stellar physics. The rapid development of asteroseismology, with the advent of space missions partly dedicated to this discipline, has provided new constraints to progress on this issue. We here give an overview of the information that can be obtained from pressure modes, gravity modes and mixed modes. We also review some of the most recent constraints obtained from space-based asteroseismology on the nature and the amount of mixing beyond convective cores.

[49]  arXiv:2001.04210 [pdf, other]

Title: Magnetosphere of an orbiting neutron star

Authors: Federico Carrasco, Masaru Shibata

Comments: 16 pages, 13 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

We conduct force-free simulations of a single neutron star undergoing orbital motion in flat spacetime, mimicking the trajectory of the star about the center of mass on a compact binary system. Our attention is focused on the kinetic energy being extracted from the orbit by the acceleration of the magnetic dipole moment of the neutron star, and particularly, on how this energy gets distributed within its surrounding magnetosphere. A detailed study of the resulting magnetospheric configurations in our setting is presented, incorporating as well the effects due to neutron star spin and the misalignment of the magnetic and orbital axes. We find many features resembling those of pulsar magnetospheres for the orbiting neutron star --even in the absence of spin--, being of particular interest the development of a spiral current sheet that extends beyond the light cylinder. Then, we use recent advances in pulsar theory to estimate electromagnetic emissions produced at the reconnection regions of such current sheets.

[50]  arXiv:2001.04302 [pdf, ps, other]

Title: Post-Newtonian Magnetohydrodynamics

Authors: Jai-chan Hwang, Hyerim Noh

Comments: 10 pages, no figure

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

Using the fully nonlinear and exact perturbation formulation with magnetohydrodynamics (MHD) in Minkowski background we derive first-order post-Newtonian (1PN) equations without imposing the slicing (temporal gauge) condition. The 1PN MHD formulation is complementary to our recently presented fully relativistic MHD combined with 0PN gravity available only in the maximal slicing. We present the 1PN MHD equations in two gauge conditions previously used in the literature and provide gauge transformation relations between different gauges. We derive the PN effects on MHD waves in a static homogeneous medium.

[51]  arXiv:2001.04303 [pdf, other]

Title: Dust emission from the first massive galaxies

Authors: Maria Emilia De Rossi, George H. Rieke, Irene Shivaei, Volker Bromm, Jianwei Lyu

Comments: 3 pages, 2 figures. Accepted for publication in BAAA, Vol. 61B, 2020

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We compare observed far-infrared (FIR) galaxy spectral energy distributions (SEDs) at $z\sim6$ and theoretical predictions for first massive population II (Pop II) galaxies. Observed FIR SEDs at $z\gtrsim5$ are broad and shifted to bluer wavelengths when compared to galaxies at $z\sim3$. By implementing an analytical model for dust emission from Pop II massive galaxies,we were able to reproduce the observed behaviour as a consequence of the high energy densities and silicate-rich dust composition of high-$z$ model galaxies. As noted in a previous work, the non-blackbody nature of galaxy SEDs at $z \sim 6$ should be taken into account when interpreting measurements of FIR luminosities to avoid underestimating star formation rates.

[52]  arXiv:2001.04304 [pdf, other]

Title: Simulated mass measurements of the young planet K2-33b

Authors: Baptiste Klein, Jean-François Donati

Comments: Letter accepted in MNRAS, 6 pages, 3 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

In this paper, we carry out simulations of radial velocity (RV) measurements of the mass of the 8-11 Myr Neptune-sized planet K2-33b using high-precision near infrared velocimeters like SPIRou at the Canada-France-Hawaii Telescope. We generate a RV curve containing a planet signature and a realistic stellar activity signal, computed for a central wavelength of 1.8 $\mu$m and statistically compatible with the light-curve obtained with K2. The modelled activity signal includes the effect of time-evolving dark and bright surface features hosting a 2 kG radial magnetic field, resulting in a RV signal of semi-amplitude ~30 m/s. Assuming a 3-month visibility window, we build RV time-series including Gaussian white noise from which we retrieve the planet mass while filtering the stellar activity signal using Gaussian Process Regression. We find that 35/50 visits spread over 3 consecutive bright-time runs on K2-33 allow one to reliably detect planet RV signatures of respectively 10 and 5 m/s at precisions larger than 3 $\sigma$. We also show that 30 visits may end up being insufficient in some cases to provide a good coverage of the stellar rotation cycle, with the result that the planet signature can go undetected or the mass estimation be plagued by large errors.

[53]  arXiv:2001.04307 [pdf, other]

Title: Metastable dark energy models in light of Planck 2018: Alleviating the $H_0$ tension

Authors: Weiqiang Yang, Eleonora Di Valentino, Supriya Pan, Spyros Basilakos, Andronikos Paliathanasis

Comments: 14 pages, 7 figures and 3 tables. Comments are welcome

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

We investigate the recently introduced metastable dark energy (DE) models after the final Planck 2018 legacy release. The essence of the present work is to analyze their evolution at the level of perturbations. Our analyses show that both the metastable dark energy models considered in this article, are excellent candidates to alleviate the $H_0$ tension. In particular, for the present models, Planck 2018 alone can alleviate the $H_0$ tension within 68\% CL. Along with the final cosmic microwave background data from the Planck 2018 legacy release, we also include external cosmological datasets in order to asses the robustness of our findings.

[54]  arXiv:2001.04354 [pdf, ps, other]

Title: The AGORA high-resolution galaxy simulations comparison project: Public data release

Authors: Santi Roca-Fàbrega, Ji-hoon Kim, Joel R. Primack, Michael J. Butler, Daniel Ceverino, Jun-Hwan Choi, Robert Feldmann, Ben W. Keller, Alessandro Lupi, Kentaro Negamine, Thomas R. Quinn, Yves Revaz, Romain Teyssier, Spencer C. Wallace (for the AGORA Collaboration)

Comments: AGORA links: this http URL and this http URL

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)

As part of the AGORA High-resolution Galaxy Simulations Comparison Project (Kim et al. 2014, 2016) we have generated a suite of isolated Milky Way-mass galaxy simulations using 9 state-of-the-art gravito-hydrodynamics codes widely used in the numerical galaxy formation community. In these simulations weadopted identical galactic disk initial conditions, and common physics models (e.g., radiative cooling and ul-traviolet background by a standardized package). Subgrid physics models such as Jeans pressure floor, starformation, supernova feedback energy, and metal production were carefully constrained. Here we release thesimulation data to be freely used by the community. In this release we include the disk snapshots at 0 and 500Myr of evolution per each code as used in Kim et al. (2016), from simulations with and without star formationand feedback. We encourage any member of the numerical galaxy formation community to make use of theseresources for their research - for example, compare their own simulations with the AGORA galaxies, with thecommon analysisytscripts used to obtain the plots shown in our papers, also available in this release.

[55]  arXiv:2001.04357 [pdf, other]

Title: Reduction of Saturn Orbit Insertion Impulse using Deep-Space Low Thrust

Authors: Elena Fantino, Roberto Flores, Jesus Pelaez, Virginia Raposo-Pulido

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Optimization and Control (math.OC)

Orbit insertion at Saturn requires a large impulsive manoeuver due to the velocity difference between the spacecraft and the planet. This paper presents a strategy to reduce dramatically the hyperbolic excess speed at Saturn by means of deep-space electric propulsion. The interplanetary trajectory includes a gravity assist at Jupiter, combined with low-thrust maneuvers. The thrust arc from Earth to Jupiter lowers the launch energy requirement, while an ad hoc steering law applied after the Jupiter flyby reduces the hyperbolic excess speed upon arrival at Saturn. This lowers the orbit insertion impulse to the point where capture is possible even with a gravity assist with Titan. The control-law algorithm, the benefits to the mass budget and the main technological aspects are presented and discussed. The simple steering law is compared with a trajectory optimizer to evaluate the quality of the results and possibilities for improvement.

[56]  arXiv:2001.04371 [pdf, other]

Title: On the Primordial Black Hole Mass Function for Broad Spectra

Authors: V. De Luca, G. Franciolini, A. Riotto

Comments: 14 pages, 3 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)

We elaborate on the mass function of primordial black holes in the case in which the power spectrum of the curvature perturbation is broad. For the case of a broad and flat spectrum, we argue that such a mass function is peaked at the smallest primordial black mass which can be formed and possesses a tail decaying like $M^{-3/2}$, where $M$ is the mass of the primordial black hole.

[57]  arXiv:2001.04378 [pdf, other]

Title: Evidence of Spectral Evolution on the white dwarf sample from the Gaia Mission

Authors: G. Ourique, S. O. Kepler, A. D. Romero, T. S. Klippel, D. Koester

Comments: 9 pages, 9 figures, accepted by MNRAS

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Since the Gaia data release 2, several works were published describing a bifurcation in the observed white dwarf colour$-$magnitude diagram for $\mbox{$G_{\mathrm{BP}}$}-\mbox{$G_{\mathrm{RP}}$} > 0$. Some possible explanations in the literature include the existence of a double population with different initial mass function or two distinct populations, one formed by hydrogen$-$ and one formed by helium$-$envelope white dwarfs. We propose instead spectral evolution to explain the bifurcation. From a population synthesis approach, we find that the spectral evolution occurs for effective temperature below ${\simeq}11\,000\,\mathrm{K}$ and masses mainly between $0.64\,\mathrm{M}_\odot$ and $0.74\,\mathrm{M}_\odot$, which correspond to around $16$ per cent of all DA white dwarfs. We also find the Gaia white dwarf colour-magnitude diagram indicates a star formation history that decreases abruptly for objects younger than $1.4\,\mathrm{Gyr}$ and a top-heavy initial mass function for the white dwarf progenitors.

[58]  arXiv:2001.04384 [pdf, other]

Title: A hydrodynamical study of outflows in starburst galaxies with different driving mechanisms

Authors: B. P. Brian Yu, Ellis R. Owen, Kinwah Wu, Ignacio Ferreras

Comments: 16 pages, 9 figures, 3 tables, accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Outflows from starburst galaxies can be driven by thermal pressure, radiation and cosmic rays. We present an analytic phenomenological model that accounts for these contributions simultaneously to investigate their effects on the hydrodynamical properties of outflows. We assess the impact of energy injection, wind opacity, magnetic field strength and the mass of the host galaxy on flow velocity, temperature, density and pressure profiles. For an M82-like wind, a thermally-dominated driving mechanism is found to deliver the fastest and hottest wind. Radiation-driven winds in typical starburst-galaxy configurations are unable to attain the higher flow velocities and temperatures associated with thermal and cosmic ray-driven systems, leading to higher wind densities which would be more susceptible to cooling and fragmentation at lower altitudes. High opacity winds are more sensitive to radiative driving, but terminal flow velocities are still lower than those achieved by other driving mechanisms at realistic opacities. We demonstrate that variations in the outflow magnetic field can influence its coupling with cosmic rays, where stronger fields enable greater streaming but less driving near the base of the flow, instead with cosmic rays redirecting their driving impact to higher altitudes. The gravitational potential is less important in M82-like wind configurations, and substantial variations in the flow profiles only emerge at high altitude in massive haloes. This model offers a more generalised approach to examine the large scale hydrodynamical properties for a wide variety of starburst galaxies.

[59]  arXiv:2001.04386 [pdf, ps, other]

Title: The Proper Motion of Sagittarius A*: III. The Case for a Supermassive Black Hole

Authors: M. J. Reid, A. Brunthaler

Comments: 19 pages, 4 figures and 4 tables

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We report measurements with the Very Long Baseline Array of the proper motion of Sgr A* relative to two extragalactic radio sources spanning 18 years. The apparent motion of Sgr A* is -6.411 +/- 0.008 mas/yr along the Galactic plane and -0.219 +/- 0.007 mas/yr toward the North Galactic Pole. This apparent motion can almost entirely be attributed to the effects of the Sun's orbit about the Galactic center. Removing these effects yields residuals of -0.58 +/- 2.23 km/s in the direction of Galactic rotation and -0.85 +/- 0.75 km/s toward the North Galactic Pole. A maximum-likelihood analysis of the motion, both in the Galactic plane and perpendicular to it, expected for a massive object within the Galactic center stellar cluster indicates that the radiative source, Sgr A*, contains more than about 25% of the gravitational mass of 4 x 10^6 Msun deduced from stellar orbits. The intrinsic size of Sgr A* is comparable to its Schwarzschild radius, and the implied mass density of >4 x 10^23 Msun/pc^-3 very close to that expected for a black hole, providing overwhelming evidence that it is indeed a super-massive black hole. Finally, the existence of "intermediate-mass" black holes more massive than 3 x 10^4 Msun between approximately 0.003 and 0.1 pc from Sgr A*are excluded.

[60]  arXiv:2001.04408 [pdf, other]

Title: Pantheon update on a model-independent analysis of cosmological supernova data

Authors: A. K. Çamlıbel, İ. Semiz, M. A. Feyizoğlu

Comments: 23 pages, 12 figures, 5 tables. The authors promise to keep an expanded and continuously updated version of table 4 (calculations of the transition redshift in the literature) online for as long as possible and reasonable

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

We present an update of our previous work, necessitated by availability of a significantly improved dataset. The work is a model-independent analysis of the cosmological supernova (Type Ia) data, where function families are fit to the data in form of luminosity distance as function of redshift, that is, $d_{L}(z)$; and subsequently time-derivatives of the scale function $a(t)$ are $analytically$ derived, but as functions of $z$, without making assumptions about of gravity or the contents of the universe. This gives, e.g. the redshift value at which the universe goes over from deceleration to acceleration, as $z_{t}=0.54 \pm 0.04$ for a flat universe. In the update, we switch to a more modern fit criterion and also take into account the uncertainty in the calibration of the SNIa luminosities.
If a theory of gravity $is$ assumed, our results allow determination of the density of the universe as function of $z$, from which conclusions about the contents of the universe can be drawn. We update the previous work's result where this was done for Einstein gravity, finding a lower-limit on the dark energy fraction, $\Omega_{DE}>0.46$; and here we do this also for Starobinsky gravity, where we can find a Starobinsky parameter that can eliminate the need for dark energy.

[61]  arXiv:2001.04412 [pdf, other]

Title: ANTARES and IceCube Combined Search for Neutrino Point-like and Extended Sources in the Southern Sky

Authors: ANTARES Collaboration: A. Albert, M. André, M. Anghinolfi, G. Anton, M. Ardid, J.-J. Aubert, J. Aublin, B. Baret, S. Basa, B. Belhorma, V. Bertin, S. Biagi, M. Bissinger, J. Boumaaza, S. Bourret, M. Bouta, M.C. Bouwhuis, H. Brânzaş, R. Bruijn, J. Brunner, J. Busto, A. Capone, L. Caramete, J. Carr, S. Celli, M. Chabab, T. N. Chau, R. Cherkaoui El Moursli, T. Chiarusi, M. Circella, A. Coleiro, M. Colomer, R. Coniglione, H. Costantini, P. Coyle, A. Creusot, A. F. Díaz, G. de Wasseige, A. Deschamps, C. Distefano, I. Di Palma, A. Domi, C. Donzaud, D. Dornic, D. Drouhin, T. Eberl, I. El Bojaddaini, N. El Khayati, D. Elsässer, A. Enzenhöfer, A. Ettahiri, F. Fassi, P. Fermani, G. Ferrara, F. Filippini, L. Fusco, P. Gay, H. Glotin, R. Gozzini, R. Gracia Ruiz, K. Graf, et al. (443 additional authors not shown)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

A search for point-like and extended sources of cosmic neutrinos using data collected by the ANTARES and IceCube neutrino telescopes is presented. The data set consists of all the track-like and shower-like events pointing in the direction of the Southern Sky included in the nine-year ANTARES point-source analysis, combined with the through-going track-like events used in the seven-year IceCube point-source search. The advantageous field of view of ANTARES and the large size of IceCube are exploited to improve the sensitivity in the Southern Sky by a factor $\sim$2 compared to both individual analyses. In this work, the Southern Sky is scanned for possible excesses of spatial clustering, and the positions of preselected candidate sources are investigated. In addition, special focus is given to the region around the Galactic Centre, whereby a dedicated search at the location of SgrA* is performed, and to the location of the supernova remnant RXJ 1713.7-3946. No significant evidence for cosmic neutrino sources is found and upper limits on the flux from the various searches are presented.

[62]  arXiv:2001.04442 [pdf, other]

Title: The theory of Pulsar Wind Nebulae: recent progress

Authors: Elena Amato (INAF/Arcetri)

Comments: invited talk at "High Energy Phenomena in Relativistic Outflows VII - HEPRO VII", 9-12 July 2019, Proceedings of Science

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Pulsar Wind Nebulae are highly intriguing astrophysical objects in many respects. They are the brightest and closest class of relativistic sources, and hence the ultimate laboratory for the physics of relativistic plasmas: several processes observed (or inferred to occur) in other classes of relativistic sources can here be studied with unique detail, like the acceleration and collimation of relativistic outflows, or the acceleration of particles at relativistic shocks.
Here I review the current status of our theoretical understanding of Pulsar Wind Nebulae in light of the most recent 2D and 3D MHD modelling of these sources. I will discuss how these studies are taking us to the point when we can reliably use multi-wavelength observations of these nebulae as a diagnostics of the hidden physics of the pulsar wind and of the mechanism(s) through which particles are accelerated at the highly relativistic shock that terminates the wind.
Finally I will briefly discuss recent progress in the modelling of evolved Pulsar Wind Nebulae and of the escape of particles from these systems. This effort is instrumental to credibly assess the role of Pulsar Winds as sources of cosmic ray leptons, and has recently been recognised to have important implications also on cosmic ray transport in the Galaxy.

[63]  arXiv:2001.04448 [pdf, other]

Title: Four New Self-lensing Binaries from Kepler: Radial Velocity Characterization and Astrophysical Implications

Authors: Kento Masuda, Hajime Kawahara, David W. Latham, Allyson Bieryla, Morgan MacLeod, Masanobu Kunitomo, Othman Benomar, Wako Aoki

Comments: 4 pages, 2 figures, contributed to the Proceedings of IAU Symposium No. 357, "White Dwarfs as Probes of Fundamental Physics and Tracers of Planetary, Stellar, and Galactic Evolution," held in Hilo, HI, 21-25 October 2019

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

In Kawahara et al. (2018) and Masuda et al. (2019), we reported the discovery of four self-lensing binaries consisting of F/G-type stars and (most likely) white dwarfs whose masses range from 0.2 to 0.6 solar masses. Here we present their updated system parameters based on new radial velocity data from the Tillinghast Reflector Echelle Spectrograph at the Fred Lawrence Whipple Observatory, and the Gaia parallaxes and spectroscopic parameters of the primary stars. We also briefly discuss the astrophysical implications of these findings.

[64]  arXiv:2001.04453 [pdf, other]

Title: Faint LAEs near z>4.7 CIV absorbers revealed by MUSE

Authors: C. Gonzalo Diaz, Emma Ryan-Weber, Wouter Karman, Karina Caputi, Stefania Salvadori, Neil Crighton, Masami Ouchi, Eros Vanzella

Comments: 21 pages, 23 figures, 3 tables. Submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We present the results from the search for Lyman Alpha emitters (LAEs) in the proximity of 11 CIV absorption systems at $z > 4.7$ in the spectrum of the QSO J1030+0524, using data from MUSE. We have found multiple LAE candidates close to four CIV systems at $z_{CIV} = 4.94$-5.74 with log$_{10}$(N CIV[cm$^{-2}$])$ > 13.5.$ At z = 5-6, CIV systems with W0(CIV) $> 0.2$ {\AA} seem more likely to have galaxies with Ly${\alpha}$ emission within $\rho < 200$ proper kpc (4/5 cases), than the CIV systems with W0(CIV)$ < 0.2$ {\AA} (0/6 cases). The impact parameter of LAE-CIV systems with equivalent widths W0(CIV)$ > 0.5 $ {\AA} is in the range 11 $ < \rho <$ 200 proper kpc (pkpc). Furthermore, all candidates are in the luminosity range 0.18-1.15 L*$(Ly{ \alpha }, z = 5.7)$ indicating that the environment of CIV systems within 200 pkpc is populated by the faint end of the Ly${\alpha}$ luminosity function. We report a 0.28 L*$(Ly{\alpha})$ galaxy at a separation of $\rho = 10$ pkpc from a strong CIV absorption (log10(NCIV[cm$^{-2}$]) = 14.52) at $z_{CIV} = 5.72419$. The prevalence of sub-L*(Ly$\alpha$) galaxies in the proximity of z $> 4.9$ CIV systems suggest that the absorbing material is rather young, likely ejected in the recent past of the galaxies at these redshifts. The connection between faint LAEs and high-ionization absorption systems reported in this work, is potentially a consequence of the role of low mass galaxies in the early evolution of the circum-galactic and intergalactic media.

[65]  arXiv:2001.04454 [pdf, other]

Title: Constraint on the mass of Fuzzy Dark Matter from the rotation curve of Milky Way

Authors: Alireza Maleki, Shant Baghram, Sohrab Rahvar

Comments: 6 pages, 4 figures, 2 tables

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

The fuzzy Dark Matter (FDM) is one of the recent models for dark matter. According to this model, dark matter is made of very light scalar particles with considerable quantum mechanical effects on the galactic scales which solves many problems of the Cold Dark Matter (CDM). Here we use the observed data from the rotation curve of the Milky Way (MW) galaxy to compare the results from FDM and CDM models. We show that FDM adds a local peak on the rotation curve close to the center of the bulge where its position and amplitude depend on the mass of FDM particles. From fitting the observed rotation curve with our expectation from FDM, we find the mass of FDM to be $m = 2.5^{+3.6}_{-2.0} \times10^{-21}$eV. We note that the local peak of the rotation curve in MW can also be explained in the CDM model with an extra inner bulge model for the MW galaxy. We conclude that the FDM model explains this peak without need to extra structure for the bulge.

Cross-lists for Tue, 14 Jan 20

[66]  arXiv:1906.03140 (cross-list from gr-qc) [pdf, ps, other]

Title: Thermodynamics of uncharged relativistic multifluids

Authors: Lorenzo Gavassino, Marco Antonelli

Comments: 22 pages, preprint version (typos fixed and minor changes), comments welcome

Journal-ref: Classical and Quantum Gravity, Volume 37, Number 2 - Published 31 December 2019

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)

The internal layers of neutron stars are expected to contain several superfluid components that can significantly affect their dynamics. The description of such objects should rely on hydrodynamic models in which it is possible to unambiguously assign the value of the thermodynamic variables from microscopic calculations of the properties of matter. In this work we consider the phenomenological approach to multifluids modelling championed by Carter and, studying the relaxation of the system towards equilibrium, we assign a precise thermodynamic interpretation to its variables. We show that in thermodynamic equilibrium the equation of state contains less state variables than those needed in the phenomenological model, implying the existence of a gauge freedom of the theory that can be used to simplify the hydrodynamic formulation in the non-dissipative limit. Once this is understood, it becomes easy to translate the different multifluid formalisms that have been proposed in the literature into Carter's form. Finally, we show that the usual concepts of affinity and reaction coordinates, as they are introduced in chemistry, are not affected by the presence of superfluid currents. In an effort to make the concepts clear, the formalism is developed step-by-step from first principles, providing model examples and several applications of practical relevance for the study of superfluid neutron star interiors.

[67]  arXiv:2001.03633 (cross-list from hep-th) [pdf, other]

Title: The Cosmological Heavy Ion Collider: Fast Thermalization after Cosmic Inflation

Authors: Evan McDonough

Comments: 7 pages

Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)

Heavy-ion colliders have revealed the process of "fast thermalization". This experimental break-through has led to new theoretical tools to study the thermalization process at both weak and strong coupling. We apply this to the reheating epoch of inflationary cosmology, and the formation of a cosmological quark gluon plasma (QGP). We compute the thermalization time of the QGP at reheating, and find it is determined by the energy scale of inflation and the shear viscosity to entropy ratio $\eta/s$; or equivalently, the tensor-to-scalar ratio and the strong coupling constant at the epoch of thermalization. Thermalization is achieved near-instantaneously in low-scale inflation and in strongly coupled systems, and takes less than an e-fold of expansion for weakly-coupled systems or after high-scale inflation. We then consider the potential for observing this process: we demonstrate that the cosmic microwave background is largely insensitive, and the shift in $n_s$ and $r$ is well below the sensitivity of CMB S4 and Simons Observatory. We also find a stochastic background of gravitational waves at frequencies accessible by interferometers, albeit at a level unobservable by even next generation experiments.

[68]  arXiv:2001.03669 (cross-list from nucl-th) [pdf, ps, other]

Title: Bayesian inference of the skewness parameter of supra-dense nuclear matter from energetic heavy-ion reactions

Authors: Wen-Jie Xie, Bao-An Li

Comments: 20 pages with 4 figures

Subjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)

Within the Bayesian framework using available constraining bands on the pressure in symmetric nuclear matter (SNM) derived earlier by others in the density range of 1.3$\rho_0$ to 4.5$\rho_0$ from kaon production and nuclear collective flow data in energetic heavy-ion collisions, we infer the posterior probability distribution functions (PDFs) of SNM incompressibility $K_0$ and skewness $J_0$ using uniform prior PDFs for them in the ranges of $220\leq K_0\leq 260$ MeV and $-800\leq J_0\leq 400$ MeV. The 68\% posterior credible boundaries around the most probable values of $K_0$ and $J_0$ are found to be 222$\pm$2 MeV and -215$\pm$20 MeV, respectively, much narrower than their prior ranges widely used currently in the literature and are consistent with the results of a recent Bayesian analysis of neutron star properties constrained by available X-ray and gravitational wave observations.

[69]  arXiv:2001.03677 (cross-list from hep-ph) [pdf, other]

Title: Nuclear effects in high-energy neutrino interactions

Authors: Spencer R. Klein, Sally A. Robertson, Ramona Vogt

Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

Neutrino telescopes like IceCube, KM3NeT and Baikal-GVD offer physicists the opportunity to study neutrinos with energies far beyond the reach of terrestrial accelerators. These neutrinos are used to study high-energy neutrino interactions and to probe the Earth through absorption tomography. Current studies of TeV neutrinos use cross sections which are calculated for free nucleons with targets which are assumed to contain equal numbers of protons and neutrons.
Here we consider modifications of high-energy neutrino interactions due to two nuclear effects: modifications of the parton densities in the nucleus, referred to here as shadowing, and the effect of non-isoscalar targets, with unequal numbers of neutrons and protons. Both these effects depend on the interaction medium. Because shadowing is larger for heavier nuclei, such as iron, found in the Earth's core, it introduces a zenith-angle dependent change in the absorption cross section. These modifications increase the cross sections by 1-2\% at energies below 100 TeV (antishadowing), and reduce it by 3-4\% at higher energies (shadowing).
Nuclear effects also alter the inelasticity distribution of neutrino interactions in water/ice by increasing the number of low inelasticity interactions, with a larger effect for $\nu$ than $\bar\nu$. These effects are particularly large in the energy range below a few TeV. These effects could alter the cross sections inferred from events with tracks originating within the active detector volume as well as the ratio $\nu/\bar\nu$ inferred from inelasticity measurements.
The uncertainties in these nuclear effects are larger than the uncertainties on the free-proton cross sections and will thus limit the systematic precision of future high-precision measurements at neutrino telescopes.

[70]  arXiv:2001.03691 (cross-list from hep-ph) [pdf, ps, other]

Title: Neutrino spin and spin-flavor oscillations in matter currents and magnetic fields

Authors: Pavel Pustoshny, Vadim Shakhov, Alexander Studenikin

Comments: 6 pages in LaTex, to appear in the proceedings of the European Physical Society Conference on High Energy Physics - EPS-HEP2019 - 10-17 July, 2019, Ghent, Belgium

Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)

After a brief history of two known types of neutrino mixing and oscillations, including neutrino spin and spin-flavour oscillations in the transversal magnetic field, we perform systematic study of a new phenomenon of neutrino spin and spin-flavour oscillations engendered by the transversal matter currents on the bases of the developed quantum treatment of the phenomenon. Possibilities for the resonance amplification of these new types of oscillations by the longitudinal matter currents and longitudinal magnetic fields are analyzed. We also consider modifications of the oscillation probabilities due to possible arbitrary orientation of the magnetic field vector ${\bf B}$ and the matter velocity ${\bf v}$.

[71]  arXiv:2001.03859 (cross-list from nucl-th) [pdf, ps, other]

Title: Nucleon effective mass in hot dense matter

Authors: X. L. Shang, A. Li, Z. Q. Miao, G. F. Burgio, H.-J. Schulze

Comments: 7 pages, 5 figures, 1 table

Subjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

Nucleon effective masses are studied in the framework of the Brueckner-Hartree-Fock many-body approach at finite temperature. Self-consistent calculations using the Argonne $V_{18}$ interaction including microscopic three-body forces are reported for varying temperature and proton fraction up to several times the nuclear saturation density. Our calculations are based on the exact treatment of the center-of-mass momentum instead of the average-momentum approximation employed in previous works. We discuss in detail the effects of the temperature together with those of the three-body forces, the density, and the isospin asymmetry. We also provide an analytical fit of the effective mass taking these dependencies into account. The temperature effects on the cooling of neutron stars are briefly discussed based on the results for betastable matter.

[72]  arXiv:2001.04464 (cross-list from hep-ph) [pdf, other]

Title: QCD Axion Window and False Vacuum Higgs Inflation

Authors: Hiroki Matsui, Fuminobu Takahashi, Wen Yin

Comments: 31 pages, 4 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

The abundance of the QCD axion is known to be suppressed if the Hubble parameter during inflation, $H_{\rm inf}$, is lower than the QCD scale, and if the inflation lasts sufficiently long. We show that the tight upper bound on the inflation scale can be significantly relaxed if the eternal old inflation is driven by the standard-model Higgs field trapped in a false vacuum at large field values. Specifically, $H_{\rm inf}$ can be larger than $100\,$GeV if the false vacuum is located above the intermediate scale. We also discuss the slow-roll inflation after the tunneling from the false vacuum to the electroweak vacuum.

Replacements for Tue, 14 Jan 20

[73]  arXiv:1511.00491 (replaced) [pdf, ps, other]

Title: Non-minimal derivative coupling gravity in cosmology

Authors: Burin Gumjudpai (IF Naresuan), Phongsaphat Rangdee (IF Naresuan)

Comments: 11 pages, 2 figures with additional references and corrections

Journal-ref: General Relativity and Gravitation 47 (2015) 140

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)

[74]  arXiv:1610.00376 (replaced) [pdf, ps, other]

Title: Thermodynamics and phase transition in rotational Kiselev black hole

Authors: Zhaoyi Xu, Yi Liao, Jiancheng Wang

Comments: 19pages,2figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)

[75]  arXiv:1810.03539 (replaced) [pdf, ps, other]

Title: The projected mass distribution and the transition to homogeneity

Authors: Jose Gaite

Comments: 15 pages, 13 figures; new results: shot noise suppression, fractional moments; more definite conclusions

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Data Analysis, Statistics and Probability (physics.data-an)

[76]  arXiv:1810.11007 (replaced) [pdf, other]

Title: Ginzburg-Landau Theory of Dark Energy: A Framework to Study Both Temporal and Spatial Cosmological Tensions Simultaneously

Authors: Abdolali Banihashemi, Nima Khosravi, Amir H. Shirazi

Comments: 7 pages with 1 table and 4 figures. 10 figures and 2 tables in Appendix. Published version. Comments are welcome!

Journal-ref: Phys. Rev. D 99, 083509 (2019)

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Statistical Mechanics (cond-mat.stat-mech); General Relativity and Quantum Cosmology (gr-qc)

[77]  arXiv:1812.06883 (replaced) [pdf, other]

Title: On the occurrence of fast neutrino flavor conversions in multidimensional supernova models

Authors: Sajad Abbar, Huaiyu Duan, Kohsuke Sumiyoshi, Tomoya Takiwaki, Maria Cristina Volpe

Journal-ref: Phys. Rev. D 100, 043004 (2019)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[78]  arXiv:1904.04146 (replaced) [pdf, other]

Title: A study of temporary captures and collisions in the Circular Restricted Three-Body Problem with normalizations of the Levi-Civita Hamiltonian

Authors: Rocio Isabel Paez, Massimiliano Guzzo (Dip. di Matematica, Universita di Padova, Italy)

Comments: 17 pages, 9 figures. v1: original preprint. v2: author's accepted manuscript. To appear in International Journal of Non-Linear Mechanics

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Mathematical Physics (math-ph)

[79]  arXiv:1905.01184 (replaced) [pdf, other]

Title: Toward a direct measurement of the cosmic acceleration: roadmap and forecast on FAST

Authors: Kang Jiao, Jian-Chen Zhang, Tong-Jie Zhang, Hao-Ran Yu, Ming Zhu, Di Li

Comments: Accepted for publication in JCAP; 14 pages, 6 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[80]  arXiv:1906.08275 (replaced) [pdf, other]

Title: A Simple Phenomenological Emergent Dark Energy Model can Resolve the Hubble Tension

Authors: Xiaolei Li, Arman Shafieloo

Comments: 7 pages, 4 figures, 1 table, published in ApJL

Journal-ref: The Astrophysical Journal Letters (2019), 883(1), L3

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)

[81]  arXiv:1906.10825 (replaced) [pdf, other]

Title: A new cosmological probe from supermassive black hole shadows

Authors: Jing-Zhao Qi, Xin Zhang

Comments: 5 pages, 3 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)

[82]  arXiv:1907.02488 (replaced) [pdf, other]

Title: Effect of polarisation and choice of event generator on spectra from dark matter annihilations

Authors: Carl Niblaeus, Jonathan M. Cornell, Joakim Edsjö

Comments: 27 pages, 13 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)

[83]  arXiv:1907.03460 (replaced) [pdf, ps, other]

Title: Constraints on individual supermassive binary black holes using observations of PSR J1909-3744

Authors: Yi Feng, Di Li, Yan-Rong Li, Jian-Min Wang

Comments: Accepted by Research in Astronomy and Astrophysics

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)

[84]  arXiv:1907.03897 (replaced) [pdf, other]

Title: Future Prospects for Probing Scalar-Tensor Theories with Gravitational Waves from Mixed Binaries

Authors: Zack Carson, Brian C. Seymour, Kent Yagi

Comments: 8 pages, 8 figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)

[85]  arXiv:1907.04445 (replaced) [pdf, other]

Title: Diffuser-Assisted Infrared Transit Photometry for Four Dynamically Interacting \textit{Kepler} Systems

Authors: Shreyas Vissapragada, Daniel Jontof-Hutter, Avi Shporer, Heather A. Knutson, Leo Liu, Daniel Thorngren, Eve J. Lee, Yayaati Chachan, Dimitri Mawet, Maxwell A. Millar-Blanchaer, Ricky Nilsson, Samaporn Tinyanont, Gautam Vasisht, Jason Wright

Comments: 33 pages, 18 figures, accepted by AJ

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

[86]  arXiv:1907.05264 (replaced) [pdf, other]

Title: Searching for gamma-ray emission from galaxy clusters at low redshift

Authors: Manuel Colavincenzo, Xiuhui Tan, Simone Ammazzalorso, Stefano Camera, Marco Regis, Jun-Qing Xia, Nicolao Fornengo

Comments: 24 pages, 17 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)

[87]  arXiv:1907.07522 (replaced) [pdf, other]

Title: Real-time cosmology with SKA

Authors: Yan Liu, Jing-Fei Zhang, Xin Zhang

Comments: 12 pages, 5 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)

[88]  arXiv:1907.08205 (replaced) [src]

Title: Tidal radii of main sequence stars -- I. Physical tidal radius, semi-analytic model and their implications

Authors: Taeho Ryu, Julian Krolik, Tsvi Piran, Scott Noble

Comments: We significantly changed the structure of this paper (with a new title) enough to be considered as completely new papers as a response to the referee's report. We emphasize that our results have not been changed, but only new results (consistent with those presented in Papers I, II and III previously posted) have been added. We submitted the new version with the new title (arXiv:2001.03501)

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

[89]  arXiv:1907.11222 (replaced) [pdf, other]

Title: Decaying dark matter at IceCube and its signature on High Energy gamma experiments

Authors: Marco Chianese, Damiano F. G. Fiorillo, Gennaro Miele, Stefano Morisi, Ofelia Pisanti

Comments: 19 pages, 8 figures

Journal-ref: JCAP 1911 (2019)

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)

[90]  arXiv:1907.11883 (replaced) [src]

Title: Tidal radii of main sequence stars -- II. Simulation methodology and the character of full tidal disruptions

Authors: Taeho Ryu, Julian Krolik, Tsvi Piran, Scott Noble

Comments: We significantly changed the structure of this paper (with a new title) as a response to the referee's report. We emphasize that our results have not been changed, but added more explanations for our numerical methods. We submitted the new version with the new title (arXiv:2001.03502)

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

[91]  arXiv:1908.00232 (replaced) [pdf, other]

Title: Upper limits on the amplitude of ultra-high-frequency gravitational waves from graviton-photon mixing

Authors: Aldo Ejlli, Damian Ejlli, Adrian Mike Cruise, Giampaolo Pisano, Hartmut Grote

Journal-ref: Eur. Phys. J. C 79, 1032 (2019)

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex); High Energy Physics - Theory (hep-th); Instrumentation and Detectors (physics.ins-det)

[92]  arXiv:1908.05720 (replaced) [pdf, other]

Title: Excitation of Tumbling in Phobos and Deimos

Authors: Alice C. Quillen, Mckenzie Lane, Miki Nakajima, Esteban Wright

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

[93]  arXiv:1909.00095 (replaced) [pdf, other]

Title: Significance of Gravitational Nonlinearities on the Dynamics of Disk Galaxies

Authors: Alexandre Deur, Corey Sargent, Balša Terzić

Subjects: Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc)

[94]  arXiv:1909.01105 (replaced) [pdf, other]

Title: Magnetorotational core collapse of possible GRB progenitors. I. Explosion mechanisms

Authors: M. Obergaulinger (TU Darmstadt), M.Á. Aloy (U Valencia)

Comments: 23 pages, 19 figures. Accepted for publication in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[95]  arXiv:1909.02978 (replaced) [pdf, other]

Title: Gravitational wave and collider signals in complex two-Higgs doublet model with dynamical CP-violation at finite temperature

Authors: Xiao Wang, Fa Peng Huang, Xinmin Zhang

Comments: Accepted version by Physical Review D, 35 pages, 9 figures, 7 tables

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[96]  arXiv:1909.04041 (replaced) [src]

Title: Tidal radii of main sequence stars -- III. Partial disruptions

Authors: Taeho Ryu, Julian Krolik, Tsvi Piran, Scott C. Noble

Comments: We have significantly revised this paper as a response to the referee's report. So we submitted the revised version with a new title as a new paper (arXiv:2001.03503) without replacing the old version

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

[97]  arXiv:1909.04740 (replaced) [pdf, other]

Title: Keck Observations Confirm a Super-Jupiter Planet Orbiting M-dwarf OGLE-2005-BLG-071L

Authors: David P. Bennett, Aparna Bhattacharya, Jean-Philippe Beaulieu, Joshua W. Blackman, Aikaterini Vandorou, Sean K. Terry, Andrew A. Cole, Calen B. Henderson, Naoki Koshimoto, Jessica R. Lu, Jean Baptiste Marquette, Clement Ranc, Andrzej Udalski

Comments: accepted by AJ

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

[98]  arXiv:1909.05261 (replaced) [pdf, other]

Title: An accurate perturbative approach to redshift space clustering of biased tracers in modified gravity

Authors: Georgios Valogiannis, Rachel Bean, Alejandro Aviles

Comments: 43 pages, 9 figures. Updated to match published version in JCAP

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

[99]  arXiv:1910.07311 (replaced) [pdf, other]

Title: Toward a robust inference method for the likelihood of low-luminosity gamma-ray bursts to be progenitors of ultrahigh-energy cosmic rays correlating with starburst galaxies

Authors: Luis A. Anchordoqui, Claire Mechmann, Jorge F. Soriano

Comments: Matching version accepted for publication in JHEAp

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)

[100]  arXiv:1910.07526 (replaced) [pdf, other]

Title: Cross-correlation of the thermal Sunyaev-Zel'dovich effect and weak gravitational lensing: Planck and Subaru Hyper Suprime-Cam first-year data

Authors: Ken Osato, Masato Shirasaki, Hironao Miyatake, Daisuke Nagai, Naoki Yoshida, Masamune Oguri, Ryuichi Takahashi

Comments: 27 pages, 20 figures, MNRAS in press

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[101]  arXiv:1910.08656 (replaced) [pdf, ps, other]

Title: Cloud fragmentation cascades and feedback: on reconciling an unfettered inertial range with a low star formation rate

Authors: Eric G. Blackman

Comments: 6 pages, submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[102]  arXiv:1910.13754 (replaced) [pdf, other]

Title: HCN/HNC intensity ratio: a new chemical thermometer for the molecular ISM

Authors: A. Hacar, A. D. Bosman, E. F. van Dishoeck

Comments: 20 pages, 14 figures, Accepted by A&A (v2.0)

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[103]  arXiv:1911.04793 (replaced) [pdf, other]

Title: HD 117214 debris disk: scattered-light images and constraints on the presence of planets

Authors: N. Engler, C. Lazzoni, R. Gratton, J. Milli, H.M. Schmid, G. Chauvin, Q. Kral, N. Pawellek, P. Thébault, A. Boccaletti, M. Bonnefoy, S. Brown, T. Buey, F. Cantalloube, M. Carle, A. Cheetham, S. Desidera, M. Feldt, C. Ginski, D. Gisler, Th. Henning, S. Hunziker, A.M. Lagrange, M. Langlois, D. Mesa, M.R. Meyer, O. Moeller-Nilsson, J. Olofsson, C. Petit, S. Petrus, S.P. Quanz, E. Rickman, E. Stadler, T. Stolker, A. Vigan, F. Wildi, A. Zurlo

Comments: 20 pages

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

[104]  arXiv:1911.06046 (replaced) [pdf, ps, other]

Title: Modified Cosmology Models from Thermodynamical Approach

Authors: Chao-Qiang Geng, Yan-Ting Hsu, Jhih-Rong Lu, Lu Yin

Comments: 17 pages, 12 figures, published version in EPJC

Journal-ref: Eur. Phys. J. C80, 21 (2020)

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

[105]  arXiv:1911.09083 (replaced) [pdf, other]

Title: Machine-learning non-stationary noise out of gravitational wave detectors

Authors: Gabriele Vajente, Yiwen Huang, Maximiliano Isi, Jenne C. Driggers, Jeffrey S. Kissel, Marek J. Szczepanczyk, Salvatore Vitale

Subjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM); Machine Learning (cs.LG); Data Analysis, Statistics and Probability (physics.data-an); Instrumentation and Detectors (physics.ins-det)

[106]  arXiv:1911.09568 (replaced) [pdf, other]

Title: XMM-Newton Campaign On Ultraluminous X-ray Source NGC 1313 X-1: Wind vs. State Variability

Authors: C. Pinto, D. J. Walton, E. Kara, M. L. Parker, R. Soria, P. Kosec, M. J. Middleton, W. N. Alston, A. C. Fabian, M. Guainazzi, T. P. Roberts, F. Fuerst, H. P. Earnshaw, R. Sathyaprakash, D. Barret

Comments: 20 pages, 16 figures, 4 tables, accepted for publication in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[107]  arXiv:1911.12357 (replaced) [pdf, other]

Title: The Formation of a 70 Msun Black Hole at High Metallicity

Authors: K. Belczynski, R. Hirschi, E.A. Kaiser, Jifeng Liu, J. Casares, Youjun Lu, R. O'Shaughnessy, A. Heger, S. Justham, R. Soria

Comments: ApJ: after 2nd review

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

[108]  arXiv:1912.00737 (replaced) [pdf, ps, other]

Title: Brownian motion approach to anomalous rotation of galaxies

Authors: Alexander Jurisch

Comments: 8 pages, 4 figures

Subjects: Statistical Mechanics (cond-mat.stat-mech); Astrophysics of Galaxies (astro-ph.GA)

[109]  arXiv:1912.01418 (replaced) [pdf, other]

Title: Time variability of low angular momentum accretion flows around black hole

Authors: Ishika Palit, Agnieszka Janiuk, Petra Sukova

Comments: 9 pages, 4 figures, contribution to the Proceedings of the High Energy Phenomena in Relativistic Outflows VII - HEPRO VII, Barcelona, Spain (submitted in PoS (Proceedings of Science) )

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[110]  arXiv:1912.09459 (replaced) [pdf, other]

Title: Spatial Power Spectra of Dust across the Local Group: No Constraint on Disc Scale Height

Authors: Eric W. Koch, I-Da Chiang, Dyas Utomo, Jérémy Chastenet, Adam K. Leroy, Erik W. Rosolowsky, Karin M. Sandstrom

Comments: Accepted by MNRAS; 19 pgs, 10 figures. Supplementary figures of the power spectrum fits for each band can be viewed here: this https URL

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[111]  arXiv:1912.12632 (replaced) [pdf, other]

Title: MCMCI: A code to fully characterise an exoplanetary system

Authors: Andrea Bonfanti, Michaël Gillon

Comments: 18 pages, 6 figures, 6 tables. Accepted for publication in A&A. Source code link: this https URL

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

[112]  arXiv:1912.12679 (replaced) [pdf, other]

Title: The tale of the tail -- disentangling the high transverse velocity stars in Gaia DR2

Authors: João A. S. Amarante, Martin C. Smith, Corrado Boeche

Comments: Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[113]  arXiv:2001.00025 (replaced) [pdf, ps, other]

Title: Over 78 000 RR Lyrae Stars in the Galactic Bulge and Disk from the OGLE Survey

Authors: I. Soszyński, A. Udalski, M. Wrona, M. K. Szymański, P. Pietrukowicz, J. Skowron, D. Skowron, R. Poleski, S. Kozłowski, P. Mróz, K. Ulaczyk, K. Rybicki, P. Iwanek, M. Gromadzki

Comments: 17 pages, 5 figures

Journal-ref: Acta Astronomica (2019) 69, 321

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

[114]  arXiv:2001.00275 (replaced) [pdf, ps, other]

Title: Reduction of the canonical Hamiltonian of the metric GR to its natural form

Authors: Alexei M. Frolov

Subjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM)

[115]  arXiv:2001.02617 (replaced) [pdf, ps, other]

Title: Lack of Debye and Meissner screening in strongly magnetized quark matter at intermediate densities

Authors: Bo Feng, Efrain J. Ferrer, Israel Portillo

Comments: 16 pages, 4 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)

[116]  arXiv:2001.02634 (replaced) [pdf, other]

Title: On the Lambda-evolution of galaxy clusters

Authors: V.G. Gurzadyan, A.A. Kocharyan, A. Stepanian

Comments: 7 pages, 5 figs, Eur.Phys. J. C (in press), to match the published version

Journal-ref: Eur. Phys. J. C, 80:24 (2020)

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

[117]  arXiv:2001.03135 (replaced) [pdf, other]

Title: X-ray Detected AGN in SDSS Dwarf Galaxies

Authors: Keir L Birchall, M G Watson, J Aird

Comments: 19 pages, 12 figures, 1 table. Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[118]  arXiv:2001.03594 (replaced) [pdf, other]

Title: A broadband look of the Accreting Millisecond X-ray Pulsar SAX J1748.9-2021 using AstroSat and XMM-Newton

Authors: Rahul Sharma, Aru Beri, Andrea Sanna, Anjan Dutta

Comments: 9 pages, 8 figures. Accepted for publication in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

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