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New submissions for Wed, 29 Apr 20

[1]  arXiv:2004.13001 [pdf]

Title: Optical design of diffraction-limited X-ray telescopes

Authors: Brandon D. Chalifoux (1), Ralf K. Heilmann (1), Herman L. Marshall (1), Mark L. Schattenburg (1) ((1) MIT)

Comments: 20 pages, 11 figures, accepted for publication in Applied Optics

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

Astronomical imaging with micro-arcsecond ($\mu$as) angular resolution could enable breakthrough scientific discoveries. Previously-proposed $\mu$as X-ray imager designs have been interferometers with limited effective collecting area. Here we describe X-ray telescopes achieving diffraction-limited performance over a wide energy band with large effective area, employing a nested-shell architecture with grazing-incidence mirrors, while matching the optical path lengths between all shells. We present two compact nested-shell Wolter Type 2 grazing-incidence telescope designs for diffraction-limited X-ray imaging: a micro-arcsecond telescope design with 14 $\mu$as angular resolution and 2.9 m$^2$ of effective area at 5 keV photon energy ($\lambda$=0.25 nm), and a smaller milli-arcsecond telescope design with 525 $\mu$as resolution and 645 cm$^2$ effective area at 1 keV ($\lambda$=1.24 nm). We describe how to match the optical path lengths between all shells in a compact mirror assembly, and investigate chromatic and off-axis aberrations. Chromatic aberration results from total external reflection off of mirror surfaces, and we greatly mitigate its effects by slightly adjusting the path lengths in each mirror shell. The mirror surface height error and alignment requirements for diffraction-limited performance are challenging but arguably achieveable in the coming decades. Since the focal ratio for a diffraction-limited X-ray telescope is extremely large ($f/D$~10$^5$), the only important off-axis aberration is curvature of field, so a 1 arcsecond field of view is feasible with a flat detector. The detector must fly in formation with the mirror assembly, but relative positioning tolerances are on the order of 1 m over a distance of some tens to hundreds of kilometers. While there are many challenges to achieving diffraction-limited X-ray imaging, we did not find any fundamental barriers.

[2]  arXiv:2004.13025 [pdf, other]

Title: The GLEAM 4-Jy (G4Jy) Sample: II. Host-galaxy identification for individual sources

Authors: Sarah V. White, Thomas M.O. Franzen, Chris J. Riseley, O. Ivy Wong, Anna D. Kapińska, Natasha Hurley-Walker, Joseph R. Callingham, Kshitij Thorat, Chen Wu, Paul Hancock, Richard W. Hunstead, Nick Seymour, Jesse Swan, Randall Wayth, John Morgan, Rajan Chhetri, Carole Jackson, Stuart Weston, Martin Bell, B.M. Gaensler, Melanie Johnston-Hollitt, André Offringa, Lister Staveley-Smith

Comments: 37 pages (24 MB in size), 23 figures, 3 tables, accepted for publication in PASA. Full-resolution images will be used for the published version, available through the journal

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

The entire southern sky (Declination, $\delta <$ 30 deg) has been observed using the Murchison Widefield Array (MWA), which provides radio imaging of $\sim$2-arcmin resolution at low frequencies (72-231 MHz). This is the GaLactic and Extragalactic All-sky MWA (GLEAM) Survey, and we have previously used a combination of visual inspection, cross-checks against the literature, and internal matching to identify the 'brightest' radio-sources ($S_{\mathrm{151MHz}} >$ 4 Jy) in the extragalactic catalogue (Galactic latitude, $|b| >$ 10 deg). We refer to these 1,863 sources as the GLEAM 4-Jy (G4Jy) Sample, and use radio images (of $\leq$ 45-arcsec resolution), and multi-wavelength information, to assess their morphology and identify the galaxy that is hosting the radio emission (where appropriate). Details of how to access all of the overlays used for this work are available at https://github.com/svw26/G4Jy. Alongside this we conduct further checks against the literature, which we document in this paper for individual sources. Whilst the vast majority of the G4Jy Sample are active galactic nuclei with powerful radio-jets, we highlight that it also contains a nebula, two nearby, star-forming galaxies, a cluster relic, and a cluster halo. There are also three extended sources for which we are unable to infer the mechanism that gives rise to the low-frequency emission. In the G4Jy catalogue we provide mid-infrared identifications for 86% of the sources, and flag the remainder as: having an uncertain identification (129 sources), having a faint/uncharacterised mid-infrared host (126 sources), or it being inappropriate to specify a host (2 sources). For the subset of 129 sources, there is ambiguity concerning candidate host-galaxies, and this includes four sources (B0424$-$728, B0703$-$451, 3C 198, and 3C 403.1) where we question the existing identification.

[3]  arXiv:2004.13028 [pdf, other]

Title: Shock within a shock: revisiting the radio flares of NS merger ejecta and GRB-supernovae

Authors: Ben Margalit, Tsvi Piran

Comments: submitted to MNRAS; comments welcome!

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

Fast ejecta expelled in binary neutron star (NS) mergers or energetic supernovae (SNe) should produce late-time synchrotron radio emission as the ejecta shocks into the surrounding ambient medium. Models for such radio flares typically assume the ejecta expands into an unperturbed interstellar medium (ISM). However, it is also well-known that binary NS mergers and broad-lined Ic SNe can harbor relativistic jetted outflows. In this work, we show that such jets shock the ambient ISM ahead of the ejecta, thus evacuating the medium into which the ejecta subsequently collides. Using an idealized spherically-symmetric model, we illustrate that this inhibits the ejecta radio flare at early times $t < t_{\rm col} \approx 12 \, {\rm yr} \, (E_{\rm j}/10^{49} \, {\rm erg})^{1/3} (n/1 \, {\rm cm}^{-3})^{-1/3} (v_{\rm ej}/0.1c)^{-5/3}$ where $E_{\rm j}$ is the jet energy, $n$ the ISM density, and $v_{\rm ej}$ the ejecta velocity. We also show that this can produce a sharply peaked enhancement in the light-curve at $t = t_{\rm col}$. This has implications for radio observations of GW170817 and future binary NS mergers, gamma-ray burst (GRB) SNe, decade-long radio transients such as FIRST J1419, and possibly other events where a relativistic outflow precedes a slower-moving ejecta. Future numerical work will extend these analytic estimates and treat the multi-dimensional nature of the problem.

[4]  arXiv:2004.13029 [pdf, other]

Title: The Origin of hotspots around Sgr A*: Orbital or pattern motion

Authors: Tatsuya Matsumoto, Chi-Ho Chan, Tsvi Piran

Comments: 9 pages, 6 figures, 1 table, submitted to MNRAS, comments welcome!!!

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

The Gravity Collaboration detected a near-infrared hotspot moving around Sgr A* during the 2018 July 22 flare. They fitted the partial loop the hotspot made on the sky with a circular Keplerian orbit of radius $\simeq7.5\,r_{\rm g}$ around the supermassive black hole (BH), where $r_{\rm g}$ is the gravitational radius. However, because the hotspot traversed the loop in a short time, models in which the hotspot tracks the motion of some fluid element tend to produce a best-fit trajectory smaller than the observed loop. This is true for a circular Keplerian orbit, even when BH spin is accounted for, and for motion along a RIAF streamline. A marginally bound geodesic suffers from the same problem; in addition, it is not clear what the origin of an object following the geodesic would be. The observed hotspot motion is more likely a pattern motion. Circular motion with $r\simeq12.5\,r_{\rm g}$ and a super-Keplerian speed $\simeq0.8\,c$ is a good fit. Such motion must be pattern motion because it cannot be explained by physical forces. The pattern speed is compatible with magnetohydrodynamic perturbations, provided that the magnetic field is sufficiently strong. Circular pattern motion of radius $\sim20\, r_{\rm g}$ on a plane above the BH is an equally good alternative; in this case, the hotspot may be caused by a precessing outflow interacting with a surrounding disk. As all our fits have relatively large radii, we cannot constrain the BH spin using these observations.

[5]  arXiv:2004.13032 [pdf, ps, other]

Title: Eclipsing binaries in the open cluster Ruprecht 147. III: The triple system EPIC 219552514 at the main-sequence turnoff

Authors: Guillermo Torres (1), Andrew Vanderburg (2,3), Jason L. Curtis (4), Adam L. Kraus (2), Aaron C. Rizzuto (2), Michael J. Ireland (5) ( (1) Center for Astrophysics, (2) Univ. of Texas at Austin, (3) NASA Sagan Fellow, (4) American Museum of Natural History, (5) Australian National Univ. )

Comments: 12 pages in emulateapj format, including figures and tables. Accepted for publication in The Astrophysical Journal

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

Spectroscopic observations are reported for the 2.75 day, double-lined, detached eclipsing binary EPIC 219552514 located at the turnoff of the old nearby open cluster Ruprecht 147. A joint analysis of our radial velocity measurements and the K2 light curve leads to masses of M1 = 1.509 (+0.063 / -0.056) MSun and M2 = 0.649 (+0.015 / -0.014) MSun for the primary and secondary, along with radii of R1 = 2.505 (+0.026 / -0.031) RSun and R2 = 0.652 (+0.013 / -0.012) RSun, respectively. The effective temperatures are 6180 +/- 100 K for the F7 primary and 4010 +/- 170 K for the late K secondary. The orbit is circular, and the stars' rotation appears to be synchronized with the orbital motion. This is the third eclipsing system analyzed in the same cluster, following our earlier studies of EPIC 219394517 and EPIC 219568666. By comparison with stellar evolution models from the PARSEC series, we infer an age of 2.67 (+0.39 / -0.55) Gyr that is consistent with the estimates for the other two systems. EPIC 219552514 is a hierarchical triple system, with the period of the slightly eccentric outer orbit being 463 days. The unseen tertiary is either a low-mass M dwarf or a white dwarf.

[6]  arXiv:2004.13033 [pdf, ps, other]

Title: Connecting the metallicity dependence and redshift evolution of high-mass X-ray binaries

Authors: Francesca M. Fornasini, Francesca Civano, Hyewon Suh

Comments: 13 pages, 7 figures, 2 tables

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

The integrated X-ray luminosity ($L_{\mathrm{X}}$) of high-mass X-ray binaries (HMXBs) in a galaxy is correlated with its star formation rate (SFR), and the normalization of this correlation increases with redshift. Population synthesis models suggest that the redshift evolution of $L_{\mathrm{X}}$/SFR is driven by the metallicity ($Z$) dependence of HMXBs, and the first direct evidence of this connection was recently presented using galaxies at $z\sim2$. To confirm this result with more robust measurements and better constrain the $L_{\mathrm{X}}$-SFR-$Z$ relation, we have studied the $Z$ dependence of $L_{\mathrm{X}}$/SFR at lower redshifts. Using samples of star-forming galaxies at $z=0.1-0.9$ with optical spectra from the hCOSMOS and zCOSMOS surveys, we stacked \textit{Chandra} data from the COSMOS Legacy survey to measure the average $L_{\mathrm{X}}$/SFR as a function of $Z$ in three redshift ranges: $z=0.1-0.25$, $0.25-0.4$, and $0.5-0.9$. We find no significant variation of the $L_{\mathrm{X}}$-SFR-$Z$ relation with redshift. Our results provide further evidence that the $Z$ dependence of HMXBs is responsible for the redshift evolution of $L_{\mathrm{X}}$/SFR. Combining all available $z>0$ measurements together, we derive a best-fitting $L_{\mathrm{X}}$-SFR-$Z$ relation and assess how different population synthesis models describe the data. These results provide the strongest constraints to date on the $L_{\mathrm{X}}$-SFR-$Z$ relation in the range of $8.0<$12+log(O/H)$<9.0$.

[7]  arXiv:2004.13037 [pdf, other]

Title: Asteroseismic modeling of gravity modes in slowly rotating A/F stars with radiative levitation

Authors: Joey S. G. Mombarg, Aaron Dotter, Timothy Van Reeth, Andrew Tkachenko, Sarah Gebruers, Conny Aerts

Comments: Accepted for publication in ApJ

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

It has been known for several decades that transport of chemical elements is induced by the process of microscopic atomic diffusion. Yet, the effect of atomic diffusion, including radiative levitation, has hardly been studied in the context of gravity mode pulsations of core-hydrogen burning stars. In this paper, we study the difference in the properties of such modes for models with and without atomic diffusion. We perform asteroseismic modeling of two slowly rotating A- and F-type pulsators, KIC11145123 ($f_{\rm rot} \approx0.010~{\rm d}^{-1}$) and KIC9751996 ($f_{\rm rot} \approx0.0696~{\rm d}^{-1}$), respectively, based on the periods of individual gravity modes. For both stars, we find models whose g-mode periods are in very good agreement with the {\it Kepler\/} asteroseismic data, keeping in mind that the theoretical/numerical precision of present-day stellar evolution models is typically about two orders of magnitude lower than the measurement errors. Using the Akaike Information Criterion (AIC) we have made a comparison between our best models with and without diffusion, and found very strong evidence for signatures of atomic diffusion in the pulsations of KIC11145123. In the case of KIC9751996 the models with atomic diffusion are not able to explain the data as well as the models without it. Furthermore, we compare the observed surface abundances with those predicted by the best fitting models. The observed abundances are inconclusive for KIC9751996, while those of KIC11145123 from the literature can better be explained by a model with atomic diffusion.

[8]  arXiv:2004.13038 [pdf, ps, other]

Title: Evolution and Role of Mergers in the BCG-Cluster Alignment. A View from Cosmological Hydro-Simulations

Authors: Cinthia Ragone-Figueroa, Gian Luigi Granato, Stefano Borgani, Roberto De Propris, Diego Garcia Lambas, Giuseppe Murante, Elena Rasia, Michael West

Comments: 10 pages, 8 figures. Submitted to MNRAS. Comments welcome

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

Contradictory results have been reported on the time evolution of the alignment between clusters and their Brightest Cluster Galaxy (BCG). We study this topic by analyzing cosmological hydro-simulations of 24 massive clusters with $M_{200}|_{z=0} \gtrsim 10^{15}\, M_\odot$, plus 5 less massive with $1 \times 10^{14} \lesssim M_{200}|_{z=0} \lesssim 7 \times 10^{14}\, M_\odot$, which have already proven to produce realistic BCG masses. We compute the BCG alignment with both the distribution of cluster galaxies and the dark matter (DM) halo. At redshift $z=0$, the major axes of the simulated BCGs and their host cluster galaxy distributions are aligned on average within 20$^\circ$. The BCG alignment with the DM halo is even tighter. The alignment persists up to $z\lesssim2$ with no evident evolution. This result continues, although with a weaker signal, when considering the projected alignment. The cluster alignment with the surrounding distribution of matter ($3R_{200}$) is already in place at $z\sim4$ with a typical angle of $35^\circ$, before the BCG-Cluster alignment develops. The BCG turns out to be also aligned with the same matter distribution, albeit always to a lesser extent. These results taken together might imply that the BCG-Cluster alignment occurs in an outside-in fashion. Depending on their frequency and geometry, mergers can promote, destroy or weaken the alignments. Clusters that do not experience recent major mergers are typically more relaxed and aligned with their BCG. In turn, accretions closer to the cluster elongation axis tend to improve the alignment as opposed to accretions closer to the cluster minor axis.

[9]  arXiv:2004.13040 [pdf, other]

Title: A Comparison of Rotating and Binary Stellar Evolution Models: Effects on Massive Star Populations

Authors: Trevor Z. Dorn-Wallenstein, Emily M. Levesque

Comments: 17 pages, 7 figures, 2 tables. Accepted for publication in ApJ

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

Both rotation and interactions with binary companions can significantly affect massive star evolution, altering interior and surface abundances, mass loss rates and mechanisms, observed temperatures and luminosities, and their ultimate core-collapse fates. The Geneva and BPASS stellar evolution codes include detailed treatments of rotation and binary evolutionary effects, respectively, and can illustrate the impact of these phenomena on massive stars and stellar populations. However, a direct comparison of these two widely-used codes is vital if we hope to use their predictions for interpreting observations. In particular, rotating and binary models will predict different young stellar populations, impacting the outputs of stellar population synthesis (SPS) and the resulting interpretation of large massive star samples based on commonly-used tools such as star count ratios. Here we compare the Geneva and BPASS evolutionary models, using an interpolated SPS scheme introduced in our previous work and a novel Bayesian framework to present the first in-depth direct comparison of massive stellar populations produced from single, rotating, and binary non-rotating evolution models. We calculate both models' predicted values of star count ratios and compare the results to observations of massive stars in Westerlund 1, $h + \chi$ Persei, and both Magellanic Clouds. We also consider the limitations of both the observations and the models, and how to quantitatively include observational completeness limits in SPS models. We demonstrate that the methods presented here, when combined with robust stellar evolutionary models, offer a potential means of estimating the physical properties of massive stars in large stellar populations.

[10]  arXiv:2004.13042 [pdf, other]

Title: The stellar halos of ETGs in the IllustrisTNG simulations: the photometric and kinematic diversity of galaxies at large radii

Authors: C. Pulsoni, O. Gerhard, M. Arnaboldi, A. Pillepich, D. Nelson, L. Hernquist, V. Springel

Comments: submitted to A&A, 23 pages, 22 figures

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

We characterize the photometric and kinematic properties of simulated early-type galaxy (ETG) stellar halos, and compare them to observations. We select a sample of ~1200 ETGs in the TNG100 and TNG50 simulations, spanning a stellar mass range of $10^{10.3}-10^{12}M_{\odot}$ and within the range of (g-r) colour and lambda-ellipticity diagram populated by observed ETGs. We determine photometric parameters, intrinsic shapes, and kinematic observables in their extended stellar halos. We study the variation in kinematics from center to halo and connect it to a change in the intrinsic shape of the galaxies. We find that the simulated galaxy sample reproduces the diversity of kinematic properties observed in ETG halos. Simulated fast rotators (FRs) divide almost evenly in one third having flat lambda profiles and high halo rotational support, a third with gently decreasing profiles, and another third with low halo rotation. Slow rotators (SRs) tend to have increased rotation in the outskirts, with half of them exceeding lambda=0.2. For $M_{*}>10^{11.5}M_{\odot}$ halo rotation is unimportant. A similar variety of properties is found for the stellar halo intrinsic shapes. Rotational support and shape are deeply related: the kinematic transition to lower rotational support is accompanied by a change towards rounder intrinsic shape. Triaxiality in the halos of FRs increases outwards and with stellar mass. Simulated SRs have relatively constant triaxiality profiles. Simulated stellar halos show a large variety of structural properties, with quantitative but no clear qualitative differences between FRs and SRs. At the same stellar mass, stellar halo properties show a gradual transition and significant overlap between the two families, despite the clear bimodality in the central regions. This is in agreement with observations of extended photometry and kinematics. [abridged]

[11]  arXiv:2004.13044 [pdf, other]

Title: The Most Predictive Physical Properties for Stellar Population Radial Profiles of Nearby Galaxies

Authors: Guangwen Chen, Hong-Xin Zhang, Xu Kong, Zesen Lin, Zhixiong Liang, Xinkai Chen, Zuyi Chen, Zhiyuan Song

Comments: 20 pages, 12 figures, accepted for publication in ApJ

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

We present a study on the radial profiles of D4000, luminosity-weighted stellar ages $\tau_L$ and metallicities $[Z/H]_L$ of 3654 nearby galaxies ($0.01<z<0.15$) using the IFU spectroscopic data from the SDSS DR15 MaNGA data release, in an effort to explore the connection between median stellar population radial gradients (i.e., $\nabla$D4000,$\nabla\tau_L,\nabla [Z/H]_L$) out to $\sim 1.5R_e$ and various galaxy properties, including stellar mass ($M_{\star}$), specific star formation rate (sSFR), morphologies and local environment. We find that $M_{\star}$ is the single most predictive physical property for $\nabla$D4000 and $\nabla [Z/H]_L$. The most predictive properties for $\nabla\tau_L$ are sSFR and to a lesser degree, $M_{\star}$. The environmental parameters, including local galaxy overdensities and central-satellite division, have virtually no correlation with stellar population radial profiles for whole sample, but $\nabla$D4000 of star-forming satellite galaxies with $M_{\star}\lesssim 10^{10}M_\odot$ exhibit a significant positive correlation with galaxy overdensities. Galaxies with lower sSFR have on average steeper negative stellar population gradients, and this sSFR dependence is stronger for more massive star-forming galaxies. The negative correlation between median stellar population gradients and $M_{\star}$ are best described largely as segmented relationships, whereby median gradients of galaxies with $\log M_{\star}\lesssim 10$ (with the exact value depending on sSFR) have much weaker mass dependence than galaxies with higher $M_{\star}$.While the dependence of radial gradients of ages and metallicities on T-Types and central stellar mass surface densities are generally not significant, galaxies with later T-Types or lower central mass densities tend to have significantly lower D4000, younger $\tau_L$ and lower $[Z/H]_L$ across the radial ranges probed in this study.

[12]  arXiv:2004.13045 [pdf, ps, other]

Title: X-ray Binary Luminosity Function Scaling Relations in Elliptical Galaxies: Evidence for Globular Cluster Seeding of Low-Mass X-ray Binaries in Galactic Fields

Authors: Bret D. Lehmer, Andrew P. Ferrell, Keith Doore, Rafael T. Eufrasio, Erik B. Monson, David M. Alexander, Antara Basu-Zych, William N. Brandt, Greg Sivakoff, Panayiotis Tzanavaris, Mihoko Yukita, Tassos Fragos, Andrew Ptak

Comments: Accepted for publication in ApJS. Data products and catalogs available at this https URL

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

We investigate X-ray binary (XRB) luminosity function (XLF) scaling relations for Chandra detected populations of low-mass XRBs (LMXBs) within the footprints of 24 early-type galaxies. Our sample includes Chandra and HST observed galaxies at D < 25 Mpc that have estimates of the globular cluster (GC) specific frequency (SN) reported in the literature. As such, we are able to directly classify X-ray-detected sources as being either coincident with unrelated background/foreground objects, GCs, or sources that are within the fields of the galaxy targets. We model the GC and field LMXB population XLFs for all galaxies separately, and then construct global models characterizing how the LMXB XLFs vary with galaxy stellar mass and SN. We find that our field LMXB XLF models require a component that scales with SN, and has a shape consistent with that found for the GC LMXB XLF. We take this to indicate that GCs are "seeding" the galactic field LMXB population, through the ejection of GC-LMXBs and/or the diffusion of the GCs in the galactic fields themselves. However, we also find that an important LMXB XLF component is required for all galaxies that scales with stellar mass, implying that a substantial population of LMXBs are formed "in situ," which dominates the LMXB population emission for galaxies with SN < 2. For the first time, we provide a framework quantifying how directly-associated GC LMXBs, GC-seeded LMXBs, and in-situ LMXBs contribute to LMXB XLFs in the broader early-type galaxy population.

[13]  arXiv:2004.13046 [pdf, other]

Title: Combined analysis of Planck and SPTPol data favors the early dark energy models

Authors: Anton Chudaykin, Dmitry Gorbunov, Nikita Nedelko

Comments: 28 pages, 6 figures, 3 tables. SPTPol likelihoods for montepython environment are available at this https URL

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

We propose a novel method that utilizes both Planck and SPTPol cosmological datasets. We show that our combined approach predicts consistent lensing-induced smoothing of acoustic peaks within $\Lambda$CDM cosmology and yields the robust predictions of the cosmological parameters. Combining only the Planck and the SPTPol polarization and lensing measurements within $\Lambda$CDM model our framework brings the late-time parameter $S_8=\sigma_8\sqrt{\Omega_m/0.3}=0.764\pm0.022$ into accordance with cosmic shear and clustering measurements. It also raises up the Hubble constant $H_0=69.7\pm1{\rm \,\,km\,s^{-1}Mpc^{-1}}$ that reduces the Hubble tension to the $2.5\sigma$ level. We examine the residual tension in the Early Dark Energy (EDE) model which produces the brief energy injection prior to recombination. We implement both the background and perturbation evolutions of the scalar field which potential scales as $V(\phi)\propto \phi^{2n}$. We found that EDE completely alleviates the Hubble tension and significantly improves the goodness-of-fit by $2.9\sigma$ in comparison with the concordance $\Lambda$CDM model. The account for the intermediate-redshift data (the supernova dataset and baryon acoustic oscillation data) fits perfectly to our parameter predictions and indicates the preference of EDE over $\Lambda$CDM at $3\sigma$.

[14]  arXiv:2004.13048 [pdf, other]

Title: HOLISMOKES -- II. Identifying galaxy-scale strong gravitational lenses in Pan-STARRS using convolutional neural networks

Authors: R. Canameras, S. Schuldt, S. H. Suyu, S. Taubenberger, T. Meinhardt, L. Leal-Taixe, C. Lemon, K. Rojas, E. Savary

Comments: 18 pages and 11 figures (plus appendix), submitted to A&A

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

We present a systematic search for wide-separation (Einstein radius >1.5"), galaxy-scale strong lenses in the 30 000 sq.deg of the Pan-STARRS 3pi survey on the Northern sky. With long time delays of a few days to weeks, such systems are particularly well suited for catching strongly lensed supernovae with spatially-resolved multiple images and open new perspectives on early-phase supernova spectroscopy and cosmography. We produce a set of realistic simulations by painting lensed COSMOS sources on Pan-STARRS image cutouts of lens luminous red galaxies with known redshift and velocity dispersion from SDSS. First of all, we compute the photometry of mock lenses in gri bands and apply a simple catalog-level neural network to identify a sample of 1050207 galaxies with similar colors and magnitudes as the mocks. Secondly, we train a convolutional neural network (CNN) on Pan-STARRS gri image cutouts to classify this sample and obtain sets of 105760 and 12382 lens candidates with scores pCNN>0.5 and >0.9, respectively. Extensive tests show that CNN performances rely heavily on the design of lens simulations and choice of negative examples for training, but little on the network architecture. Finally, we visually inspect all galaxies with pCNN>0.9 to assemble a final set of 330 high-quality newly-discovered lens candidates while recovering 23 published systems. For a subset, SDSS spectroscopy on the lens central regions proves our method correctly identifies lens LRGs at z~0.1-0.7. Five spectra also show robust signatures of high-redshift background sources and Pan-STARRS imaging confirms one of them as a quadruply-imaged red source at z_s = 1.185 strongly lensed by a foreground LRG at z_d = 0.3155. In the future, we expect that the efficient and automated two-step classification method presented in this paper will be applicable to the deeper gri stacks from the LSST with minor adjustments.

[15]  arXiv:2004.13053 [pdf, other]

Title: Molecular scale height in spiral galaxies

Authors: Narendra Nath Patra (Raman Research Institute)

Comments: Published in MNRAS

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

Having to have low thermal energy, the molecular gas in galaxies is expected to settle in a thin disc near the midplane. However, contradicting this understanding, recent studies have revealed considerably thick molecular discs in nearby spiral galaxies. To understand this apparent discrepancy, we theoretically model the molecular discs in a sample of eight nearby spiral galaxies and estimate their molecular scale heights (Half Width at Half Maxima (HWHM)). We assume that the baryonic discs are in vertical hydrostatic equilibrium under their mutual gravity in the external force field of the dark matter halo. We set up the joint Poisson's-Boltzman equation of hydrostatic equilibrium and numerically solve it to obtain the three-dimensional molecular gas distribution and determine the scale heights in our sample galaxies. We find that the scale heights follow a universal exponential law with a scale length of $0.46 \pm 0.01 \ r_{25}$. The molecular scale heights in our sample galaxies are found to vary between 50-200 pc depending on the galaxy and radius. Using the density solutions, we build dynamical models of the molecular discs and produce molecular column density maps. These model maps found to match to the observed ones reasonably well. We further incline the dynamical models to an inclination of 90$^o$ to estimate the expected observed thickness of the molecular discs. Interestingly it is found that at edge-on orientation, our sample galaxies under hydrostatic assumption can easily produce a few kpc thick observable molecular disc.

[16]  arXiv:2004.13054 [pdf, other]

Title: X-raying winds in distant quasars: the first high-redshift wind duty cycle

Authors: E. Bertola, M. Dadina, M. Cappi, C. Vignali, G. Chartas, B. De Marco, G. Lanzuisi, M. Giustini, E. Torresi

Comments: 18 pages, 11 figures, 7 tables, Accepted for publication in A&A

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

Theoretical models of wind-driven feedback from Active Galactic Nuclei (AGN) often identify Ultra-fast outflows (UFOs) as being the main cause for generating galaxy-size outflows, possibly the main actors in establishing the so-called AGN-galaxy co-evolution. UFOs are well characterized in local AGN but much less is known in quasars at the cosmic time when SF and AGN activity peaked ($z\simeq1-3$). It is therefore mandatory to search for evidences of UFOs in high-$z$ sources to test the wind-driven AGN feedback models. Here we present a study of Q2237+030, the Einstein Cross, a quadruply-imaged radio-quiet lensed quasar located at $z=1.695$. We performed a systematic and comprehensive temporally and spatially resolved X-ray spectral analysis of all the available Chandra and XMM-Newton data (as of September 2019). We find clear evidence for spectral variability, possibly due to absorption column density (or covering fraction) variability intrinsic to the source. We detect, for the first time in this quasar, a fast X-ray wind outflowing at $v_{\rm out}\simeq0.1c$ that would be powerful enough ($\dot{E}_{\rm kin}\simeq0.1 L_{\rm bol}$) to significantly affect the host galaxy evolution. We report also on the possible presence of an even faster component of the wind ($v_{\rm out}\sim0.5c$). Given the large sample and long time interval spanned by the analyzed X-ray data, we are able to roughly estimate, for the first time in a high-$z$ quasar, the wind duty cycle as $\approx0.46\,(0.31)$ at $90\%\,(95\%)$ confidence level. Finally, we also confirm the presence of a Fe K$\alpha$ emission line with variable energy, which we discuss in the light of microlensing effects as well as considering our findings on the source.

[17]  arXiv:2004.13056 [pdf, other]

Title: Theoretical modelling of two-component molecular discs in spiral galaxies

Authors: Narendra Nath Patra (Raman Research Institute)

Comments: Accepted for publication in A&A

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

As recent observations of the molecular discs in spiral galaxies point to the existence of a diffuse, low-density thick molecular disc along with the prominent thin one, we investigate the observational signatures of this thick disc by theoretically modelling two-component molecular discs in a sample of eight nearby spiral galaxies. Assuming a prevailing hydrostatic equilibrium, we set up and solved the joint Poisson's-Boltzmann equation to estimate the three-dimensional distribution of the molecular gas and the molecular scale height in our sample galaxies. The molecular scale height in a two-component molecular disc is found to vary between $50-300$ pc, which is higher than what is found in a single-component disc. We find that this scale height can vary significantly depending on the assumed thick disc molecular gas fraction. We also find that the molecular gas flares as a function of the radius and follows a tight exponential law with a scale length of $\left(0.48 \pm 0.01 \right) r_{25}$. We used the density solutions to produce the column density maps and spectral cubes to examine the ideal observing conditions to identify a thick molecular disc in galaxies. We find that unless the molecular disc is an edge-on system and imaged with a high spatial resolution ($\lesssim 100$ pc), it is extremely hard to identify a thick molecular disc in a column density map. The spectral analysis further reveals that at moderate to high inclination ($i \gtrsim 40^o$), spectral broadening can fictitiously introduce the signatures of a two-component disc into the spectral cube of a single-component disc. Hence, we conclude that a low inclination molecular disc imaged with high spatial resolution would serve as the ideal site for identifying the thick molecular disc in galaxies.

[18]  arXiv:2004.13065 [pdf, other]

Title: Measuring the properties of reionised bubbles with resolved Lyman alpha spectra

Authors: Charlotte A. Mason, Max Gronke

Comments: Submitted to MNRAS, 11 pages

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

Identifying and characterising reionised bubbles enables us to track both their size distribution, which depends on the primary ionising sources, and the relationship between reionisation and galaxy evolution. We demonstrate that spectrally resolved $z\gtrsim6$ Lyman-alpha (Ly$\alpha$) emission can constrain properties of reionised regions. Specifically, the distant from a source to a neutral region sets the minimum observable Ly$\alpha$ velocity offset from systemic. Detection of flux on the blue side of the Ly$\alpha$ resonance implies the source resides in a large, sufficiently ionised region that photons can escape without significant resonant absorption, and thus constrains both the sizes of and the residual neutral fractions within ionised bubbles. We estimate the extent of the region around galaxies which is optically thin to blue Ly$\alpha$ photons, analogous to quasar proximity zones, as a function of the source's ionising photon output and surrounding gas density. This optically thin region is typically $\lesssim 0.3$ pMpc in radius (allowing transmission of flux $\gtrsim -250$ km s$^{-1}$), $\lesssim 10$% of the distance to the neutral region. In a proof-of-concept, we demonstrate the $z\approx6.6$ galaxy COLA1 - with a blue Ly$\alpha$ peak - likely resides in an ionised region $>0.7$ pMpc, with residual neutral fraction $<10^{-5.5}$. To ionise its own proximity zone we infer COLA1 has a steep UV slope ($\beta < -2.27$), a high ionising photon escape fraction ($f_{\mathrm{esc}}>0.48$) and moderate line-of-sight gas density ($<2.61\times$ the cosmic mean).

[19]  arXiv:2004.13069 [pdf, other]

Title: SN 2013aa and SN 2017cbv: Two Sibling Type Ia Supernovae in the spiral galaxy NGC 5643

Authors: Christopher R Burns, Chris Ashall, Carlos Contreras, Peter Brown, Maximilian Stritzinger, M M Phillips, Ricardo Flores, Nicholas B Suntzeff, Eric Y Hsiao, Syed Uddin, Joshua D Simon, Kevin Krisciunas, Abdo Campillay, Ryan J Foley, Wendy L Freedman, Lluís Galbany, Consuelo González, Peter Hoeflich, S Holmbo, Charles D Kilpatrick, Robert P Kirshner, Nidia Morrell, Nahir Muñoz-Elgueta, Anthony L Piro, César Rojas-Bravo, David Sand, Jaime Vargas-González, Natalie Ulloa, Jorge Anais Vilchez

Comments: Accepted for publication in the Astrophysical Journal

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

We present photometric and spectroscopic observations of SN 2013aa and SN 2017cbv, two nearly identical type Ia supernovae (SNe Ia) in the host galaxy NGC 5643. The optical photometry has been obtained using the same telescope and instruments used by the Carnegie Supernova Project. This eliminates most instrumental systematics and provides light curves in a stable and well-understood photometric system. Having the same host galaxy also eliminates systematics due to distance and peculiar velocity, providing an opportunity to directly test the relative precision of SNe Ia as standard candles. The two SNe have nearly identical decline rates, negligible reddening, and remarkably similar spectra and, at a distance of $\sim 20$ Mpc, are ideal as potential calibrators for the absolute distance using primary indicators such as Cepheid variables. We discuss to what extent these two SNe can be considered twins and compare them with other supernova "siblings" in the literature and their likely progenitor scenarios. Using 12 galaxies that hosted 2 or more SNe~Ia, we find that when using SNe~Ia, and after accounting for all sources of observational error, one gets consistency in distance to 3 percent.

[20]  arXiv:2004.13079 [pdf, other]

Title: MOSEL: Strong [OIII]5007 Å Emitting Galaxies at (3<z<4) from the ZFOURGE Survey

Authors: Kim-Vy H. Tran, Ben Forrest, Leo Y. Alcorn, Tiantian Yuan, Themiya Nanayakkara, Jonathan Cohn, Michael Cowley, Karl Glazebrook, Anshu Gupta, Glenn G. Kacprzak, Lisa Kewley, Ivo Labbe, Casey Papovich, Lee Spitler, Caroline M. S. Straatman, Adam Tomczak

Comments: Astrophysical Journal, in press

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

To understand how strong emission line galaxies (ELGs) contribute to the overall growth of galaxies and star formation history of the universe, we target Strong ELGs (SELGs) from the ZFOURGE imaging survey that have blended (Hb+[OIII]) rest-frame equivalent widths of >230A and 2.5<zphot<4.0. Using Keck/MOSFIRE, we measure 49 redshifts for galaxies brighter than Ks=25 mag as part of our Multi-Object Spectroscopic Emission Line (MOSEL) survey. Our spectroscopic success rate is ~53% and zphot uncertainty is sigma_z= [Delta(z)/(1+z)]=0.0135. We confirm 31 ELGs at 3<zspec<3.8 and show that Strong ELGs have spectroscopic rest-frame [OIII]5007A equivalent widths of 100-500A and tend to be lower mass systems [log(Mstar/Msun)~8.2-9.6] compared to more typical star-forming galaxies. The Strong ELGs lie ~0.9 dex above the star-forming main-sequence at z~3.5 and have high inferred gas fractions of fgas~>60%, i.e. the inferred gas masses can easily fuel a starburst to double stellar masses within ~10-100 Myr. Combined with recent results using ZFOURGE, our analysis indicates that 1) strong [OIII]5007A emission signals an early episode of intense stellar growth in low mass (Mstar<0.1M*) galaxies and 2) many, if not most, galaxies at z>3 go through this starburst phase. If true, low-mass galaxies with strong [OIII]5007A emission (EW_rest>200A) may be an increasingly important source of ionizing UV radiation at z>3.

[21]  arXiv:2004.13113 [pdf, other]

Title: Optical Fe II and Near-Infrared Ca II triplet emission in active galaxies: (II) radial sizes from photoionization modelling

Authors: Swayamtrupta Panda

Comments: 20 pages, 18 figures, submitted to ApJ (comments are welcome)

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

I analyse the emitting regions for the optical Fe II and near-infrared Ca II emission pertaining to the broad-line region in active galaxies, using the CLOUDY photoionisation modelling to ascertain the tight correlation shown between these species. I explicitly show the connection between two physical quantities, i.e. metallicity in the BLR cloud, and, the cloud column density (N$_{\rm{H}}$) highlighting the co-dependence between them suggesting that even strong Fe II emitters, such as I Zw 1 can be modelled with metallicities that do not require values as high as shown from previous studies. The study suggests that the bulk of the Ca II emitting region is located farther in the BLR by a factor ~3 times as compared to the bulk Fe II emitting region.

[22]  arXiv:2004.13125 [pdf, other]

Title: The GLEAM 4-Jy (G4Jy) Sample: I. Definition and the catalogue

Authors: Sarah V. White, Thomas M.O. Franzen, Chris J. Riseley, O. Ivy Wong, Anna D. Kapińska, Natasha Hurley-Walker, Joseph R. Callingham, Kshitij Thorat, Chen Wu, Paul Hancock, Richard W. Hunstead, Nick Seymour, Jesse Swan, Randall Wayth, John Morgan, Rajan Chhetri, Carole Jackson, Stuart Weston, Martin Bell, Bi-Qing For, B.M. Gaensler, Melanie Johnston-Hollitt, André Offringa, Lister Staveley-Smith

Comments: 57 pages (30 MB in size), 23 figures, 16 tables, accepted for publication in PASA. Full-resolution images will be used for the published version, available through the journal. To keep up-to-date regarding the G4Jy Sample, 'watch' this repository: this https URL

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

The Murchison Widefield Array (MWA) has observed the entire southern sky (Declination, $\delta <$ 30 deg) at low radio-frequencies, over the range 72-231 MHz. These observations constitute the GaLactic and Extragalactic All-sky MWA (GLEAM) Survey, and we use the extragalactic catalogue (Galactic latitude, $|b| >$ 10 deg) to define the GLEAM 4-Jy (G4Jy) Sample. This is a complete sample of the 'brightest' radio-sources ($S_{\mathrm{151MHz}} >$ 4 Jy), the majority of which are active galactic nuclei with powerful radio-jets. Crucially, low-frequency observations allow the selection of such sources in an orientation-independent way (i.e. minimising the bias caused by Doppler boosting, inherent in high-frequency surveys). We then use higher-resolution radio images, and information at other wavelengths, to morphologically classify the brightest components in GLEAM. We also conduct cross-checks against the literature, and perform internal matching, in order to improve sample completeness (which is estimated to be $>$ 95.5%). This results in a catalogue of 1,863 sources, making the G4Jy Sample over 10 times larger than that of the revised Third Cambridge Catalogue of Radio Sources (3CRR; $S_{\mathrm{178MHz}} >$ 10.9 Jy). Of these G4Jy sources, 78 are resolved by the MWA (Phase-I) synthesised beam ($\sim$2 arcmin at 200 MHz), and we label 67% of the sample as 'single', 26% as 'double', 4% as 'triple', and 3% as having 'complex' morphology at $\sim$1 GHz (45-arcsec resolution). Alongside this, our value-added catalogue provides mid-infrared source associations (subject to 6-arcsec resolution at 3.4 micron) for the radio emission, as identified through visual inspection and thorough checks against the literature. As such, the G4Jy Sample can be used as a reliable training set for cross-identification via machine-learning algorithms. [Abstract abridged for arXiv submission.]

[23]  arXiv:2004.13155 [pdf, other]

Title: Evolution of Flare-accelerated Electrons Quantified by Spatially Resolved Analysis

Authors: Natsuha Kuroda, Gregory D. Fleishman, Dale E. Gary, Gelu M. Nita, Bin Chen, Sijie Yu

Comments: 28 pages, 10 figures, accepted in Frontiers in Astronomy and Space Sciences, section Stellar and Solar Physics

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

Nonthermal electrons accelerated in solar flares produce electromagnetic emission in two distinct, highly complementary domains - hard X-rays (HXRs) and microwaves (MWs). This paper reports MW imaging spectroscopy observations from the Expanded Owens Valley Solar Array of an M1.2 flare that occurred on 2017 September 9, from which we deduce evolving coronal parameter maps. We analyze these data jointly with the complementary Reuven Ramaty High-Energy Solar Spectroscopic Imager HXR data to reveal the spatially-resolved evolution of the nonthermal electrons in the flaring volume. We find that the high-energy portion of the nonthermal electron distribution, responsible for the MW emission, displays a much more prominent evolution (in the form of strong spectral hardening) than the low-energy portion, responsible for the HXR emission. We show that the revealed trends are consistent with a single electron population evolving according to a simplified trap-plus-precipitation model with sustained injection/acceleration of nonthermal electrons, which produces a double-powerlaw with steadily increasing break energy.

[24]  arXiv:2004.13156 [pdf]

Title: Prospective Lava Tubes at Hellas Planitia

Authors: Antonio Paris, Evan Davies, Laurence Tognetti, Carly Zahniser

Comments: 16

Journal-ref: Journal of the Washington Academy of Sciences, 2019

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

After surveying 1,500 images from MRO, this investigation has identified three candidate lava tubes in the vicinity of Hadriacus Mons as prospective sites for manned exploration. This investigation, therefore, concluded that terrestrial lava tubes can be leveraged for radiation shielding and, accordingly, that the candidate lava tubes on Mars (as well as known lava tubes on the lunar surface) can serve as natural radiation shelters and habitats for a prospective crewed mission to the planet.

[25]  arXiv:2004.13189 [pdf, other]

Title: A Quasar Microlensing Light Curve Generator for LSST

Authors: Favio Neira, Timo Anguita, Georgios Vernardos

Comments: 10 pages, 6 figures, 2 tables. Accepted for publication in MNRAS

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

We present a tool to generate mock quasar microlensing light curves and sample them according to any observing strategy. An updated treatment of the fixed and random velocity components of observer, lens, and source is used, together with a proper alignment with the external shear defining the magnification map caustic orientation. Our tool produces quantitative results on high magnification events and caustic crossings, which we use to study three lensed quasars known to display microlensing, viz. RX J1131-1231, HE 0230-2130, and Q 2237+0305, as they would be monitored by The Rubin Observatory Legacy Survey of Space and Time (LSST). We conclude that depending on the location on the sky, the lens and source redshift, and the caustic network density, the microlensing variability may deviate significantly than the expected $\sim$20-year average time scale (Mosquera & Kochanek 2011, arXiv:1104.2356). We estimate that $\sim300$ high magnification events with $\Delta$mag$>1$ mag could potentially be observed by LSST each year. The duration of the majority of high magnification events is between 10 and 100 days, requiring a very high cadence to capture and resolve them. Uniform LSST observing strategies perform the best in recovering microlensing high magnification events. Our web tool can be extended to any instrument and observing strategy, and is freely available as a service at this http URL, along with all the related code.

[26]  arXiv:2004.13199 [pdf, other]

Title: Limitations in the determination of surface emission distributions on comets through modelling of observational data -- A case study based on Rosetta observations

Authors: Raphael Marschall, Ying Liao, Nicolas Thomas, Jong-Shinn Wu

Comments: Icarus (in press)

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Fluid Dynamics (physics.flu-dyn); Space Physics (physics.space-ph)

The European Space Agency's (ESA) Rosetta mission has returned a vast data set of measurements of the inner gas coma of comet 67P/Churyumov-Gerasimenko. These measurements have been used by different groups to determine the distribution of the gas sources at the nucleus surface. The solutions that have been found differ from each other substantially and illustrate the degeneracy of this issue. It is the aim of this work to explore the limitations that current gas models have in linking the coma measurements to the surface. In particular, we discuss the sensitivity of Rosetta's ROSINA/COPS, VIRTIS, and MIRO instruments to differentiate between vastly different spatial distributions of the gas emission from the surface. We have applied a state of the art 3D DSMC gas dynamics code to simulate the inner gas coma of different models that vary in the fraction of the surface that contains ice and in different sizes of active patches. These different distributions result in jet interactions that differ in their dynamical behaviour. We have found that ROSINA/COPS measurements by themselves cannot detect the differences in our models. While ROSINA/COPS measurements are important to constrain the regional inhomogeneities of the gas emission, they can by themselves not determine the surface emission distribution of the gas sources to a spatial accuracy of better than a few hundred metres (400 m). Any solutions fitting the ROSINA/COPS measurements is hence fundamentally degenerate, be it through a forward or inverse model. Only other instruments with complementary measurements can potentially lift this degeneracy as we show here for VIRTIS and MIRO. Finally, as a by-product, we have explored the effect of our activity distributions on lateral flow at the surface that may be responsible for some of the observed aeolian features.

[27]  arXiv:2004.13200 [pdf, other]

Title: A New Radio Catalogue for M83: Supernova Remnants and H II Regions

Authors: Thomas D. Russell, Richard L. White, Knox S. Long, William P. Blair, Roberto Soria, P. Frank Winkler

Comments: 23 pages, 17 figures, 8 tables. Accepted for publication in MNRAS. The full machine-readable catalogues are provided in the source (MRT) folder

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

We present a new catalogue of radio sources in the face-on spiral galaxy M83. Radio observations taken in 2011, 2015, and 2017 with the Australia Telescope Compact Array (ATCA) at 5.5 and 9 GHz have detected 270 radio sources. Although a small number of these sources are background extragalactic sources, most are either H II regions or supernova remnants (SNRs) within M83 itself. Three of the six historical supernovae are detected, as is the very young remnant that had been identified in a recent study, which is likely the result of a supernova that exploded in the last ~100 years but was missed. All of these objects are generally fading with time. Confusion limits our ability to measure the radio emission from a number of the SNRs in M83, but 64 were detected in unconfused regions, and these have the approximate power-law luminosity function which has been observed in other galaxies. The SNRs in M83 are systematically smaller in diameter and brighter than those that have been detected at radio wavelengths in M33. A number of the radio sources are coincident with X-ray sources in M83; most of these coincident sources turn out to be supernova remnants. Our dual frequency observations are among the most sensitive to date for a spiral galaxy outside the Local Group; despite this we were not able to place realistic constraints on the spectral indices, and as a result, it was not possible to search for supernova remnants based on their radio properties alone.

[28]  arXiv:2004.13209 [pdf]

Title: Solar System Physics for Exoplanet Research

Authors: J. Horner, S. R. Kane, J. P. Marshall, P. A. Dalba, T. R. Holt, J. Wood, H. E. Maynard-Casely, R. Wittenmyer, P. S. Lykawka, M. Hill, R. Salmeron, J. Bailey, T. Löhne, M. Agnew, B. D. Carter, C. C. E. Tylor

Comments: Invited Review, Accepted for publication in Publications of the Astronomical Society of the Pacific; 23 figures, plus a further 18 in the appendix; 4 tables

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

Over the past three decades, we have witnessed one of the great revolutions in our understanding of the cosmos - the dawn of the Exoplanet Era. Where once we knew of just one planetary system (the Solar system), we now know of thousands, with new systems being announced on a weekly basis. Of the thousands of planetary systems we have found to date, however, there is only one that we can study up-close and personal - the Solar system.
In this review, we describe our current understanding of the Solar system for the exoplanetary science community - with a focus on the processes thought to have shaped the system we see today. In section one, we introduce the Solar system as a single well studied example of the many planetary systems now observed. In section two, we describe the Solar system's small body populations as we know them today - from the two hundred and five known planetary satellites to the various populations of small bodies that serve as a reminder of the system's formation and early evolution. In section three, we consider our current knowledge of the Solar system's planets, as physical bodies. In section four, we discuss the research that has been carried out into the Solar system's formation and evolution, with a focus on the information gleaned as a result of detailed studies of the system's small body populations. In section five, we discuss our current knowledge of planetary systems beyond our own - both in terms of the planets they host, and in terms of the debris that we observe orbiting their host stars.
As we learn ever more about the diversity and ubiquity of other planetary systems, our Solar system will remain the key touchstone that facilitates our understanding and modelling of those newly found systems, and we finish section five with a discussion of the future surveys that will further expand that knowledge.

[29]  arXiv:2004.13212 [pdf]

Title: Contribution of magnetism to the origin and stability of the rings of Saturn due to superconductivity of protoplanetary iced particles

Authors: Vladimir V. Tchernyi (Cherny), Sergey V. Kapranov, Andrey Yu. Pospelov

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

It is demonstrated how Saturn rings may be originated due to interaction of iced particles (with II kind superconductivity) moving by chaotic orbits within protoplanetary cloud with magnetic field of Saturn after it appearance. Eventually all orbits of particles coming to the magnetic equator plane of Saturn where they locked within three-dimensional magnetic well due to minimum of the particles magnetic energy at the magnetic equator and quantum trapping by Abrikosov vortices.

[30]  arXiv:2004.13241 [pdf, ps, other]

Title: Wind accretion in Cygnus X-1

Authors: Emmi Meyer-Hofmeister, B.F. Liu, E. Qiao, Ronald E. Taam

Comments: 8 pages, 7 figures, to appear in A&A 2020

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

Context: Cygnus X-1 is a black hole X-ray binary system in which the black hole captures and accretes gas from the strong stellar wind emitted by its supergiant O9.7 companion star. The irradiation of the supergiant star essentially determines the flow properties of the stellar wind and the X-ray luminosity from the system. The results of three-dimensional hydrodynamical simulations of wind-fed X-ray binary systems reported in recent work reveal that the ionizing feedback of the X-ray irradiation leads to the existence of two stable states with either a soft or a hard spectrum. Aims: We discuss the observed radiation of Cygnus X-1 in the soft and hard state in the context of mass flow in the corona and disk, as predicted by the recent application of a condensation model. Methods: The rates of gas condensation from the corona to the disk for Cygnus X-1 are determined, and the spectra of the hard and soft radiation are computed. The theoretical results are compared with the MAXI observations of Cygnus X-1 from 2009 to 2018. In particular, we evaluate the hardness-intensity diagrams (HIDs) for its ten episodes of soft and hard states which show that Cygnus X-1 is distinct in its spectral changes as compared to those found in the HIDs of low-mass X-ray binaries. Results: The theoretically derived values of photon counts and hardness are in approximate agreement with the observed data in the HID. However, the scatter in the diagram is not reproduced. Improved agreement could result from variations in the viscosity associated with clumping in the stellar wind and corresponding changes of the magnetic fields in the disk. The observed dipping events in the hard state may also contribute to the scatter and to a harder spectrum than predicted by the model.

[31]  arXiv:2004.13252 [pdf, ps, other]

Title: Propagation of weak shocks in cool-core galaxy clusters in two-temperature magnetohydrodynamics with anisotropic thermal conduction

Authors: S. Komarov, C. Reynolds, E. Churazov

Comments: 9 pages, 7 figures, submitted to MNRAS

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

We investigate how different magnetohydrodynamic models of propagation of a weak (Mach number ~1.2) shock in the core of a galaxy cluster affect its observational appearance, using the Perseus cluster as our fiducial model. In particular, we study how thermal conduction, both isotropic and anisotropic, and ion-electron temperature equilibration modify a weak shock. Strong thermal conduction is expected to produce an electron temperature precursor. Less prominent pressure and density precursors are formed as well. A longer equilibration time largely reduces the density precursor, but does not change the electron temperature precursor much. When thermal conduction becomes anisotropic, the intracluster magnetic field imprints its characteristic spatial scale on the distortions of the shock induced by heat fluxes.

[32]  arXiv:2004.13299 [pdf, ps, other]

Title: Solar Flares Forecasting Using Time Series and Extreme Gradient Boosting Ensembles

Authors: T. Cinto (1 and 2), A. L. S. Gradvohl (1), G. P. Coelho (1), A. E. A. da Silva (1) ((1) School of Technology - FT, University of Campinas - UNICAMP, Limeira, SP, Brazil, (2) Federal Institute of Education, Science and Technology of Rio Grande do Sul - IFRS, Campus Feliz, RS, Brazil)

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

Space weather events may cause damage to several fields, including aviation, satellites, oil and gas industries, and electrical systems, leading to economic and commercial losses. Solar flares are one of the most significant events, and refer to sudden radiation releases that can affect the Earth's atmosphere within a few hours or minutes. Therefore, it is worth designing high-performance systems for forecasting such events. Although in the literature there are many approaches for flare forecasting, there is still a lack of consensus concerning the techniques used for designing these systems. Seeking to establish some standardization while designing flare predictors, in this study we propose a novel methodology for designing such predictors, further validated with extreme gradient boosting tree classifiers and time series. This methodology relies on the following well-defined machine learning based pipeline: (i) univariate feature selection; (ii) randomized hyper-parameter optimization; (iii) imbalanced data treatment; (iv) adjustment of cut-off point of classifiers; and (v) evaluation under operational settings. To verify our methodology effectiveness, we designed and evaluated three proof-of-concept models for forecasting $\geq C$ class flares up to 72 hours ahead. Compared to baseline models, those models were able to significantly increase their scores of true skill statistics (TSS) under operational forecasting scenarios by 0.37 (predicting flares in the next 24 hours), 0.13 (predicting flares within 24-48 hours), and 0.36 (predicting flares within 48-72 hours). Besides increasing TSS, the methodology also led to significant increases in the area under the ROC curve, corroborating that we improved the positive and negative recalls of classifiers while decreasing the number of false alarms.

[33]  arXiv:2004.13307 [pdf, other]

Title: Insight-HXMT insight into switch of the accretion mode: the case of the X-ray pulsar 4U 1901+03

Authors: Y. L. Tuo, L. Ji, S. S. Tsygankov, T. Mihara, L. M. Song, M. Y. Ge, A. Nabizadeh, L. Tao, J. L. Qu, Y. Zhang, S. Zhang, S. N. Zhang, Q. C. Bu, L. Chen, Y. P. Xu, X. L. Cao, Y. Chen, C. Z. Liu, C. Cai, Z. Chang, G. Chen, T. X. Chen, Y. B. Chen, Y. P. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, Y. D. Gu, J. Guan, C. C. Guo, D. W. Han, Y. Huang, J. Huo, S. M. Jia, L. H. Jiang, W. C. Jiang, J. Jin, Y. J. Jin, L. D. Kong, B. Li, C. K. Li, G. Li, M. S. Li, T. P. Li, W. Li, X. Li, X. B. Li, X. F. Li, Y. G. Li, Z. W. Li, X. H. Liang, J. Y. Liao, B. S. Liu, G. Q. Liu, H. W. Liu, X. J. Liu, Y. N. Liu, B. Lu, F. J. Lu, X. F. Lu, Q. Luo, T. Luo, X. Ma, B. Meng, Y. Nang, J. Y. Nie, G. Ou, N. Sai, R. C. Shang, X. Y. Song, L. Sun, Y. Tan, C. Wang, G. F. Wang, et al. (43 additional authors not shown)

Comments: 8 pages, 5 figures, accepted by JHEAP

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

We use the In data collected during the 2019 outburst from X-ray pulsar 4U 1901+03 to complement the orbital parameters reported by Fermi/GBM. Using the Insight-HXMT, we examine the correlation between the derivative of the intrinsic spin frequency and bolometric flux based on accretion torque models. It was found that the pulse profiles significantly evolve during the outburst. The existence of two types of the profile's pattern discovered in the Insight-HXMT data indicates that this source experienced transition between a super-critical and a sub-critical accretion regime during its 2019 outburst. Based on the evolution of the pulse profiles and the torque model, we derive the distance to 4U 1901+03 as 12.4+-0.2 kpc.

[34]  arXiv:2004.13392 [pdf, other]

Title: Spitzer Observations of the Predicted Eddington Flare from Blazar OJ 287

Authors: Seppo Laine, Lankeswar Dey, Mauri Valtonen, A. Gopakumar, Stanislaw Zola, S. Komossa, Mark Kidger, Pauli Pihajoki, Jose L. Gómez, Daniel Caton, Stefano Ciprini, Marek Drozdz, Kosmas Gazeas, Vira Godunova, Shirin Haque, Felix Hildebrandt, Rene Hudec, Helen Jermak, Albert K.H. Kong, Harry Lehto, Alexios Liakos, Katsura Matsumoto, Markus Mugrauer, Tapio Pursimo, Daniel E. Reichart, Andrii Simon, Michal Siwak, Eda Sonbas

Comments: 8 pages, 4 figures, 1 table, to appear in ApJL

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

Binary black hole (BH) central engine description for the unique blazar OJ 287 predicted that the next secondary BH impact-induced bremsstrahlung flare should peak on 2019 July 31. This prediction was based on detailed general relativistic modeling of the secondary BH trajectory around the primary BH and its accretion disk. The expected flare was termed the Eddington flare to commemorate the centennial celebrations of now-famous solar eclipse observations to test general relativity by Sir Arthur Eddington. We analyze the multi-epoch Spitzer observations of the expected flare between 2019 July 31 and 2019 September 6, as well as baseline observations during 2019 February-March. Observed Spitzer flux density variations during the predicted outburst time display a strong similarity with the observed optical pericenter flare from OJ 287 during 2007 September. The predicted flare appears comparable to the 2007 flare after subtracting the expected higher base-level Spitzer flux densities at 3.55 and 4.49 $\mu$m compared to the optical R-band. Comparing the 2019 and 2007 outburst lightcurves and the previously calculated predictions, we find that the Eddington flare arrived within 4 hours of the predicted time. Our Spitzer observations are well consistent with the presence of a nano-Hertz gravitational wave emitting spinning massive binary BH that inspirals along a general relativistic eccentric orbit in OJ 287. These multi-epoch Spitzer observations provide a parametric constraint on the celebrated BH no-hair theorem.

[35]  arXiv:2004.13418 [pdf, other]

Title: A new look at Sco OB1 association with Gaia DR2

Authors: L. Yalyalieva, G. Carraro, R. Vazquez, L. Rizzo, E. Glushkova, E. Costa

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

We present and discuss photometric optical data in the area of the OB association Sco OB1 covering about 1 squared degree. UBVI photometry is employed in tandem with Gaia DR2 data to investigate the 3 dimensional structure and the star formation history of the region. By combining parallaxes and proper motions we identify 7 physical groups located between the young open cluster NGC 6231 and the bright nebula IC4628. The most prominent group coincides with the sparse open cluster Trumpler 24. We confirm the presence of the intermediate age star cluster VdB-Hagen 202, which is unexpected in this environment, and provide for the first time estimates of its fundamental parameters. After assessing individual groups membership, we derive mean proper motion components, distances, and ages. The seven groups belong to two different families. To the younger family (family I) belong several pre-Main Sequence stars as well. These are evenly spread across the field, and also in front of VdB-Hagen 202. VdB-Hagen 202 and two smaller, slightly detached, groups of similar properties form family II, which do not belong to the association, but are caught in the act of passing through it. As for the younger population, this forms an arc-like structure from the bright nebula IC 4628 down to NGC 6231, as previously found. Moreover, the pre-Main Sequence stars density seems to increase from NGC 6231 northward to Trumpler 24.

[36]  arXiv:2004.13422 [pdf, other]

Title: Dynamical friction with radiative feedback -- II. High resolution study of the subsonic regime

Authors: David A. Velasco-Romero, Frédéric S. Masset

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Computational Physics (physics.comp-ph); Fluid Dynamics (physics.flu-dyn)

Recent work has suggested that the net gravitational force acting on a massive and luminous perturber travelling through a gaseous and opaque medium can have same direction as the perturber's motion (an effect sometimes called negative dynamical friction). Analytic results were obtained using a linear analysis and were later confirmed by means of non-linear numerical simulations which did not resolve the flow within the Bondi sphere of the perturber, hence effectively restricted to weakly perturbed regions of the flow (paper~I). Here we present high resolution simulations, using either 3D Cartesian or 2D cylindrical meshes that resolve the flow within the Bondi sphere. We perform a systematic study of the force as a function of the perturber's mass and luminosity, in the subsonic regime. We find that perturbers with mass $M$ smaller than a few $M_c\sim \chi c_s/G$ are subjected to a thermal force with a magnitude in good agreement with linear theory ($\chi$ being the thermal diffusivity of the medium, $c_s$ the adiabatic sound speed and $G$ the gravitational constant), while for larger masses, the thermal forces are only a fraction of the linear estimate that decays as $M^{-1}$. Our analysis confirms the possibility of negative friction (hence a propulsion) on sufficiently luminous, low-mass embryos embedded in protoplanetary discs. Finally, we give an approximate expression of the total force at low Mach number, valid both for sub-critical ($M<M_c$) and super-critical ($M>M_c$) perturbers.

[37]  arXiv:2004.13426 [pdf, other]

Title: A Sample of Edge-on HI-rich low-surface-brightness Galaxy Candidates in the 40% ALFALFA Catalog

Authors: Min He, Hong Wu, Wei Du, He-yang Liu, Feng-jie Lei, Pin-song Zhao, Bing-qing Zhang

Comments: 14 pages, 7 figures, 2 tables

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

Low-surface-brightness galaxies(LSBGs) are defined as galaxies that are fainter than dark night sky and are important for studying our universe. Particularly, edge-on galaxies are useful for the study of rotational velocity and dynamical properties of galaxies. Hence here we focus on searching for edge-on LSBGs. In order to find these edge-on dim galaxies, a series of effects caused by inclination, including the surface brightness profile, internal extinction, and scale length, have been corrected. In this work, we present a catalog of 281 edge-on LSBG candidates, which are selected from the cross-match between SDSS DR7 and the 40% ALFALFA catalog. We also present the properties of these edge-on LSBG candidates including absolute magnitude, central surface brightness, B-V color, scale length, and relative thickness. Our result suggests that the correction of inclination effects is very important for obtaining a complete sample of LSBGs.

[38]  arXiv:2004.13435 [pdf, other]

Title: Galaxy mass profiles from strong lensing II: The elliptical power-law model

Authors: Conor M. O'Riordan, Stephen J. Warren, Daniel J. Mortlock

Comments: 11 pages, 8 figures. To be submitted to MNRAS

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

We present a systematic analysis of the constraints $\sigma_\gamma$ on the mass profile slope $\gamma$ obtainable when fitting a singular power-law ellipsoid model to a typical strong lensing observation of an extended source. These results extend our previous analysis of circular systems, Paper I. We draw our results from 676 mock observations covering a range of image configurations, each created with a fixed signal to noise ratio $S=100$ in the images. We analyse the results using a combination of theory and a simplified modelling technique which identifies the contribution to the constraints of the individual fluxes and positions in each of the two or four images. The main results are: 1. Regardless of the lens ellipticity, the constraints $\sigma_\gamma$ for two image systems are well described by the results of Paper I, transformed to elliptical coordinates; 2. We derive an analytical expression for $\sigma_\gamma$ for systems with the source aligned with the axis of the lens; 3. For both two-image systems and aligned systems the slope uncertainties $\sigma_\gamma$ are limited by the flux uncertainties; 4. The constraints for off-axis four-image systems are a factor of two to eight better, depending on source size, than for two-image systems, and improve with increasing lens ellipticity. We show that the constraints on $\gamma$ in these systems derive from the complementary positional information of the images and the flux measurements do not contribute to $\sigma_\gamma$. The complementarity improves as the offset of the source from the axis increases, such that the best constraints $\sigma_\gamma<0.01$, for $S=100$, occur when the source approaches the caustic.

[39]  arXiv:2004.13436 [pdf, other]

Title: Does jackknife scale really matter for accurate large-scale structure covariances?

Authors: Ginevra Favole, Benjamin R. Granett, Javier Silva Lafaurie, Domenico Sapone

Comments: 11 pages, 6 figures, 3 tables

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

The jackknife method gives an internal covariance estimate for large-scale structure surveys and allows model-independent errors on cosmological parameters. Using the SDSS-III BOSS CMASS sample, we study how the jackknife size and number of resamplings impact the precision of the covariance estimate on the correlation function multipoles and the error on the inferred baryon acoustic scale. We compare the measurement with log-normal mock galaxy catalogues with the same survey geometry. We build several jackknife configurations that vary in size and number of resamplings. We find that it is useful to apply the tapering scheme to estimate the precision matrix from a limited number of jackknife resamplings. The results from CMASS and mock catalogues show that the error estimate of the baryon acoustic scale does not depend on the jackknife scale. For the shift parameter $\alpha$, we find an average error of 1.6% and 1.2%, respectively from CMASS and mock jackknife covariances, consistent with pre-reconstruction analyses. However, when relatively few resamplings are used, the jackknife error estimate becomes unreliable. Future large-scale structure surveys will map even greater volumes allowing percent-level estimation of the covariance matrix using a jackknife approach.

[40]  arXiv:2004.13498 [pdf, other]

Title: Spectroscopic and geometrical evolution of the ejecta of the classical nova ASASSN-18fv

Authors: M. Pavana, A. Raj, T. Bohlsen, G. C. Anupama, Ranjan Gupta, G. Selvakumar

Comments: 14 pages, 12 figures, accepted in MNRAS

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

The optical spectroscopic observations of ASASSN-18fv observed from 2018 March 24 to 2019 Jan 26 are presented. The optical spectra are obtained from Mirranook, Vainu Bappu and South African Astronomical observatories. The spectra are dominated by hydrogen Balmer, Fe II and O I lines with P-Cygni profiles in the early phase, typical of an Fe II class nova. The spectra show He I lines along with H I and O I emission lines in the decline phase placing the nova in the hybrid class of novae. The spectra show rapid development in high ionization lines in this phase. Analysis of the light curve indicate t$_2$ and t$_3$ values of about 50 and 70 days respectively placing the nova in the category of moderately fast nova. The ejecta geometry, inclination and position angle are estimated using morpho-kinematic analysis. The geometry of the ejecta is found to be an asymmetric bipolar structure with an inclination angle of about 53$^{\circ}$. The ejected mass using photo-ionization analysis is found to be 6.07 $\times$ 10$^{-4}$ M$_{\odot}$.

[41]  arXiv:2004.13502 [pdf, other]

Title: Mineral snowflakes on exoplanets and brown dwarfs: Effects of micro-porosity, size distributions, and particle shape

Authors: Dominic Samra, Christiane Helling, Michiel Min

Comments: 20 pages, 15 figures, accepted for publication in A&A

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

Exoplanet atmosphere characterisation has become an important tool in understanding exoplanet formation, evolution. However, clouds remain a key challenge for characterisation: upcoming space telescopes (e.g. JWST, ARIEL) and ground-based high-resolution spectrographs (e.g. CRIRES+) will produce data requiring detailed understanding of cloud formation and cloud effects. We aim to understand how the micro-porosity of cloud particles affects the cloud structure, particle size, and material composition. We examine the spectroscopic effects of micro-porous particles, the particle size distribution, and non-spherical cloud particles. We expanded our kinetic non-equilibrium cloud formation model and use a grid of prescribed 1D (T_gas-p_gas) DRIFT-PHOENIX profiles. We applied the effective medium theory and the Mie theory to model the spectroscopic properties of cloud particles with micro-porosity and a derived particle size distribution. We used a statistical distribution of hollow spheres to represent the effects of non-spherical cloud particles. Highly micro-porous cloud particles (90% vacuum) have a larger surface area, enabling efficient bulk growth higher in the atmosphere than for compact particles. Increases in single-scattering albedo and cross-sectional area for these mineral snowflakes cause the cloud deck to become optically thin only at a wavelength of ~100 ${\rm \mu m}$ instead of at the ~20 ${\rm \mu m}$ for compact cloud particles. A significant enhancement in albedo is also seen when cloud particles occur with a locally changing Gaussian size distribution. Non-spherical particles increase the opacity of silicate spectral features, which further increases the wavelength at which the clouds become optically thin. JWST MIRI will be sensitive to signatures of micro-porous and non-spherical cloud particles based on the wavelength at which clouds are optically thin.

[42]  arXiv:2004.13534 [pdf, other]

Title: The Challenge of Forming a Fuzzy Core in Jupiter

Authors: Simon Müller, Ravit Helled, Andrew Cumming

Comments: 11 pages, 9 figures, accepted for publication in A&A

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

Recent structure models of Jupiter that match Juno gravity data suggest that the planet harbours an extended region in its deep interior that is enriched in heavy elements, a so-called dilute/fuzzy core. This finding raises the question of what possible formation pathways would lead to such a structure. We model Jupiter's formation and long-term evolution, starting at late-stage formation before runaway gas accretion. The formation scenarios we consider include both primordial composition gradients, as well as gradients that are built as proto-Jupiter rapidly acquires its gaseous envelope. We then follow Jupiter's evolution as it cools down and contracts, with a particular focus on the energy and material transport in the interior. We find that none of the scenarios we consider lead to a fuzzy core that is compatible with interior structure models. In all the cases, most of Jupiter's envelope becomes convective and fully mixed after at most a few million years. This is true even when we consider a case where the gas accretion leads to a cold planet, and large amounts of heavy elements are accreted. It is therefore concluded that it is very challenging to explain Jupiter's dilute core from standard formation models. We suggest that future work should consider more complex formation pathways as well as the modelling of additional physical processes that could lead to Jupiter's current-state internal structure.

[43]  arXiv:2004.13548 [pdf, ps, other]

Title: Estimating the nonstructural component of the helioseismic surface term using hydrodynamic simulations

Authors: J. Schou, A. C. Birch

Comments: 9 pages, 5 figures, accepted for publication in Astronomy & Astrophysics

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

As the amount of asteroseismic data available continues to grow, the inability to accurately model observed oscillation frequencies is becoming a critical problem for interpreting these frequencies. A major component of this problem is the modeling of the near-surface layers. Our aim is to develop a method to estimate the effect of the near-surface layers on oscillation frequencies. In the proposed method we numerically estimate eigenfunctions in 3D hydrodynamic simulations. We match those to the eigenfunctions calculated from the classic equations applied to the horizontal averages of the structure variables. We use this procedure to calculate the frequency perturbation resulting from the dynamical part of the interaction of the oscillations with near-surface convection. As the last step we scale the numbers to the Sun. To provide a qualitative test of our method we performed a series of simulations, calculated the perturbations using our procedure, and compared them to previously reported residuals relative to solar models. We find that we can largely reproduce the observed frequency residuals without resorting to poorly justified theoretical models. We find that, while the calculations of Houdek et al. (2017, MNRAS, 464, L124) produce similar frequency perturbations, the density-pressure phase differences computed here do not match those of that work.

[44]  arXiv:2004.13551 [pdf, other]

Title: Protoplanetary disk masses in NGC 2024: Evidence for two populations

Authors: Sierk E. van Terwisga, Ewine F. van Dishoeck, Rita K. Mann, James Di Francesco, Nienke van der Marel, Michael Meyer, Sean M. Andrews, John Carpenter, Josh A. Eisner, Carlo F. Manara, Jonathan P. Williams

Comments: Accepted for publication in A&A; 19 pages, 13 figures. Key results shown in Fig. 8 & 10

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

Protoplanetary disks in dense, massive star-forming regions are strongly affected by their environment. How this environmental impact changes over time is an important constraint on disk evolution and external photoevaporation models. We characterize the dust emission from 179 disks in the core of the young (0.5 Myr) NGC 2024 cluster. By studying how the disk mass varies within the cluster, and comparing these disks to those in other regions, we aim to determine how external photoevaporation influences disk properties over time. Using the Atacama Large Millimeter/submillimeter Array, a 2.9' x 2.9' mosaic centered on NGC 2024 FIR 3 was observed at 225 GHz with a resolution of 0.25'', or ~100 AU. The imaged region contains 179 disks identified at IR wavelengths, seven new disk candidates, and several protostars. The overall detection rate of disks is $32 \pm 4\%$. Few of the disks are resolved, with the exception of a giant (R = 300 AU) transition disk. Serendipitously, we observe a millimeter flare from an X-ray bright young stellar object (YSO), and resolve continuum emission from a Class 0 YSO in the FIR 3 core. Two distinct disk populations are present: a more massive one in the east, along the dense molecular ridge hosting the FIR 1-5 YSOs, with a detection rate of $45 \pm 7\%$. In the western population, towards IRS 1, only $15 \pm 4\%$ of disks are detected. NGC 2024 hosts two distinct disk populations. Disks along the dense molecular ridge are young (0.2 - 0.5 Myr) and partly shielded from the far ultraviolet radiation of IRS 2b; their masses are similar to isolated 1 - 3 Myr old SFRs. The western population is older and at lower extinctions, and may be affected by external photoevaporation from both IRS 1 and IRS 2b. However, it is possible these disks had lower masses to begin with.

[45]  arXiv:2004.13552 [pdf, other]

Title: Excitation of negative energy surface magnetohydrodynamic waves in an incompressible cylindrical plasma

Authors: D. J. Yu, V. M. Nakariakov

Comments: 11 pages, 8 figures, accepted in ApJ

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph)

Negative energy wave phenomena may appear in shear flows in the presence of a wave decay mechanism and external energy supply. We study the appearance of negative energy surface waves in a plasma cylinder in the incompressible limit. The cylinder is surrounded by an axial magnetic field and by a plasma of different density. Considering flow inside and viscosity outside the flux tube, we derive dispersion relations, and obtain analytical solutions for the phase speed and growth rate (increment) of the waves. It is found that the critical speed shear for the occurrence of the dissipative instability associated with negative energy waves (NEWs) and the threshold of Kelvin--Helmholtz instability (KHI) depend on the axial wavelength. The critical shear for the appearance of sausage NEW is lowest for the longest axial wavelengths, while for kink waves the minimum value of the critical shear is reached for the axial wavelength comparable to the diameter of the cylinder. The range between the critical speed of the dissipative instability and the KHI threshold is shown to depend on the difference of the Alfv\'{e}n speeds inside and outside of the cylinder. For all axial {wavenumbers}, NEW appears for the shear flow speeds lower than the KHI threshold. It is easier to excite NEW in an underdense cylinder than in an overdense one. The negative energy surface waves can be effectively generated for azimuthal number $m=0$ with a large axial wave number and for higher modes ($m>0$) with a small axial wave number.

[46]  arXiv:2004.13561 [pdf, other]

Title: Thermal evolution of protoplanetary disks: from $β$-cooling to decoupled gas and dust temperatures

Authors: Eduard I. Vorobyov (1,2) Ryoki Matsukoba (3), Kazuyuki Omukai (3), Manuel Guedel (1) ((1) University of Vienna, Department of Astrophysics, Vienna, 1180, Austria, (2) Ural Federal University, 51 Lenin Str., 620051 Ekaterinburg, Russia, (3) Astronomical Institute, Graduate School of Sciences, Tohoku University, Aoba, Sendai, Miyagi 980-8578, Japan)

Comments: 19 pages, 21 Figures, accepeted for publication in Astronomy & Astrophysics

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

Aims: We explore the long-term evolution of young protoplanetary disks with different approaches to computing the thermal structure determined by various cooling and heating processes in the disk and its surroundings. Methods: Numerical hydrodynamics simulations in the thin-disk limit were complemented with three thermal evolution schemes: a simplified $\beta$-cooling approach with and without irradiation, in which the rate of disk cooling is proportional to the local dynamical time, a fiducial model with equal dust and gas temperatures calculated taking viscous heating, irradiation, and radiative cooling into account, and also a more sophisticated approach allowing decoupled dust and gas temperatures. Results: We found that the gas temperature may significantly exceed that of dust in the outer regions of young disks thanks to additional compressional heating caused by the infalling envelope material in the early stages of disk evolution and slow collisional exchange of energy between gas and dust in low-density disk regions. The outer envelope however shows an inverse trend with the gas temperatures dropping below that of dust. The global disk evolution is only weakly sensitive to temperature decoupling. Nevertheless, separate dust and gas temperatures may affect the chemical composition, dust evolution, and disk mass estimates. Constant-$\beta$ models without stellar and background irradiation fail to reproduce the disk evolution with more sophisticated thermal schemes because of intrinsically variable nature of the $\beta$-parameter. Constant-$\beta$ models with irradiation can better match the dynamical and thermal evolution, but the agreement is still incomplete. Conclusions: Models allowing separate dust and gas temperatures are needed when emphasis is placed on the chemical or dust evolution in protoplanetary disks, particularly in sub-solar metallicity environments.

[47]  arXiv:2004.13594 [pdf, other]

Title: The photometric and polarimetric variability of magnetic O-type stars

Authors: Melissa Munoz, Gregg Wade, Daniel Faes, Alex Carciofi

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

Massive star winds are important contributors to the energy, momentum and chemical enrichment of the interstellar medium. Strong, organized and predominantly dipolar magnetic fields have been firmly detected in a small subset of massive O-type stars. Magnetic massive stars are known to exhibit phase-locked variability of numerous observable quantities that is hypothesized to arise due to the presence of an obliquely rotating magnetosphere formed via the magnetic confinement of their strong outflowing winds. Analyzing the observed modulations of magnetic O-type stars is thus a key step towards the better understanding of the physical processes that occur within their magnetospheres. The dynamical processes that lead to the formation of a magnetosphere are formally solved utilizing complex MHD simulations. Recently, an Analytic Dynamical Magnetosphere (ADM) model has been developed that can quickly be employed to compute the time-averaged density, temperature and velocity gradients within a dynamical magnetosphere. Here, we exploit the ADM model to compute photometric and polarimetric observables of magnetic Of?p stars, to test geometric models inferred from magnetometry. We showcase important results on the prototypical Of?p-type star HD 191612, that lead to a better characterization of massive star wind and magnetic properties.

[48]  arXiv:2004.13596 [pdf, other]

Title: An updated estimate of the cosmic radio background and implications for ultra-high-energy photon propagation

Authors: I. C. Niţu (1), H. T. J. Bevins (1), J. D. Bray (1), A. M. M. Scaife (1) ((1) JBCA, Dept. of Physics and Astronomy, Univ. of Manchester)

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

We present an updated estimate of the cosmic radio background (CRB) and the corresponding attenuation lengths for ultra-high energy photons. This new estimate provides associated uncertainties as a function of frequency derived from observational constraints on key physical parameters. We also present the expected variation in the spectrum of the CRB as a function of these parameters, as well as accounting for the expected variation in spectral index among the population of radio galaxies. The new estimate presented in this work shows better agreement with observational constraints from radio source-count measurements than previous calculations. In the energy regime where we expect cosmogenic photons dominantly attenuated by the CRB, our calculation of the attenuation length differs from previous estimates by a factor of up to 3, depending on energy and the specific model for comparison. These results imply a decrease in the expected number of cosmogenic photons with energies $\sim 10^{19}-10^{20}$ eV.

[49]  arXiv:2004.13597 [pdf, ps, other]

Title: Milky Way Subsystems from Globular Clusters Kinematics Using Gaia DR2 and HST Data

Authors: A. T. Bajkova, G. Carraro, V. I. Korchagin, N. O. Budanova, V. V. Bobylev

Comments: 25 pages, 10 Figures, 5 Tables. Accepted to Astrophysical Journal

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

We employ Gaia DR2 proper motions for 151 Milky Way globular clusters from Vasiliev (2019) in tandem with distances and line-of-sight velocities to derive their kinematical properties. To assign clusters to the Milky Way thick disk, bulge, and halo we follow the approach of Posti et al. (2018) who distinguished among different Galactic stellar components using stars's orbits. In particular, we use the ratio $L_{z}/e$, the $Z$ projection of the angular momentum to the eccentricity, as population tracer, which we complement with chemical abundances extracted from the literature and Monte-Carlo simulations. We find that 20 globular clusters belong to the bar/bulge of the Milky Way, 35 exhibit disk properties, and 96 are members of the halo. Moreover, we find that halo globular clusters have close to zero rotational velocity with average value $<\Theta>$ =1$\pm$ 4 km s$^{-1}$. On the other hand, the sample of clusters that belong to the thick disk possesses a significant rotation with average rotational velocity 179 $\pm$ 6 km s$^{-1}$. The twenty globular clusters orbiting within the bar/bulge region of the Milky Way galaxy have average rotational velocity of 49 $\pm$ 11 km s$^{-1}$.

[50]  arXiv:2004.13600 [pdf, other]

Title: Dynamics of long-lasting relativistic winds in Gamma Ray Bursters

Authors: Maxim Barkov (Purdue University, RIKEN, DESY), Maxim Lyutikov (Purdue University)

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

We perform numerical simulations of the dynamics of magnetized and highly relativistic pulsar-like winds produced by long-lasting central engines in Gamma Ray Bursters (GRB). The very fast wind interacts with the initial relativistically expanding GRB outflow, creating a multiple-shock structure. Depending on the parameters of the model (the energy of the initial explosion, the outside density, the wind power, the delay time for the switch-on of the wind, and the magnetization of the wind) a variety of temporal behaviors can be produced. In certain regimes the dynamics of such secondary engine-driven shocks is self-similar.

[51]  arXiv:2004.13616 [pdf, other]

Title: SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES) IV: Spatial clustering and halo masses of 450-$μ$m-selected sub-millimeter galaxies

Authors: Chen-Fatt Lim, Chian-Chou Chen, Ian Smail, Wei-Hao Wang, Wei-Leong Tee, Yen-Ting Lin, Douglas Scott, Yoshiki Toba, Yu-Yen Chang, YiPing Ao, Arif Babul, Andy Bunker, Scott C. Chapman, David L Clements, Christopher J. Conselice, Yu Gao, Thomas R. Greve, Luis C. Ho, Sungwook E. Hong, Ho Seong Hwang, Maciej Koprowski, Michał J. Michałowski, Hyunjin Shim, Xinwen Shu, James M. Simpson

Comments: ApJ accepted

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

We analyze an extremely deep 450-$\mu$m image ($1\sigma=0.56$\,mJy\,beam$^{-1}$) of a $\simeq 300$\,arcmin$^{2}$ area in the CANDELS/COSMOS field as part of the SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). We select a robust (signal-to-noise ratio $\geqslant 4$) and flux-limited ($\geqslant 4$\,mJy) sample of 164 450-$\mu$m-selected sub-millimeter galaxies (SMGs) that have $K$-band counterparts in the COSMOS2015 catalog identified from radio or mid-infrared imaging. Utilizing this SMG sample and the 4705 $K$-band-selected non-SMGs that reside within the noise level $\leqslant 1$\,mJy\,beam$^{-1}$ region of the 450-$\mu$m image as a training set, we develop a machine-learning classifier using $K$-band magnitude and color-color pairs based on the thirteen-band photometry available in this field. We apply the trained machine-learning classifier to the wider COSMOS field (1.6\,deg$^{2}$) using the same COSMOS2015 catalog and identify a sample of 6182 450-$\mu$m SMG candidates with similar colors. The number density, radio and/or mid-infrared detection rates, redshift and stellar mass distributions, and the stacked 450-$\mu$m fluxes of these SMG candidates, from the S2COSMOS observations of the wide field, agree with the measurements made in the much smaller CANDELS field, supporting the effectiveness of the classifier. Using this 450-$\mu$m SMG candidate sample, we measure the two-point autocorrelation functions from $z=3$ down to $z=0.5$. We find that the 450-$\mu$m SMG candidates reside in halos with masses of $\simeq (2.0\pm0.5) \times10^{13}\,h^{-1}\,\rm M_{\odot}$ across this redshift range. We do not find evidence of downsizing that has been suggested by other recent observational studies.

[52]  arXiv:2004.13623 [pdf, other]

Title: Can the cosmological dilation explain the skewness in the GRB duration distribution?

Authors: Mariusz Tarnopolski

Comments: 9 pages, 2 figures, 1 table. Accepted in ApJ

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

No.

[53]  arXiv:2004.13646 [pdf, other]

Title: Radial migration and vertical action in N-body simulations

Authors: Daniel Mikkola, Paul. J McMillan, David Hobbs

Comments: 13 pages, 12 figures, accepted for publication in MNRAS

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

We study the radial migration of stars as a function of orbital action as well as the structural properties of a large suite of N-body simulations of isolated disc galaxies. Our goal is to establish a relationship between the radial migration efficiency of stars and their vertical action. We aim to describe how that relationship depends on the relative gravitational dominance between the disc and the dark matter halo. By changing the mass ratio of our disc and dark matter halo we find a relationship between disc dominance, number and strength of spiral arms, and the ensuing radial migration as a function of the vertical action. We conclude that the importance of migration at large vertical action depends on the strength of the spiral arms and therefore the dominance of the disc. Populations with more radial action undergo less radial migration, independently of disc dominance. Our results are important for the future of analytical modelling of radial migration in galaxies and furthers the understanding of radial migration which is a key component of the restructuring of galaxies, including the Milky Way.

[54]  arXiv:2004.13648 [pdf, other]

Title: Testing Modified Gravity theory (MOG) with Type Ia Supernovae, Cosmic Chronometers and Baryon Acoustic Oscillations

Authors: Carolina Negrelli, Lucila Kraiselburd, Susana J. Landau, Claudia Scóccola

Comments: 14 pages, 6 figures

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

We analyse the MOdified Gravity (MOG) theory, proposed by Moffat, in a cosmological context. We use data from Type Ia Supernovae (SNe Ia), Baryon Acoustic Oscillations (BAO) and Cosmic Chronometers (CC) to test MOG predictions. For this, we perform $\chi^2$ tests considering fixed values of $H_0$ and $V_G$, the self-interaction potential of one of the scalar fields in the theory. Our results show that the MOG theory is in agreement with all data sets for some particular values of $H_0$ and $V_G$, being the BAO data set the most powerful tool to test MOG predictions, due to its constraining power.

[55]  arXiv:2004.13660 [pdf, other]

Title: Simulations of gas sloshing induced by a newly discovered gas poor substructure in galaxy cluster Abell 1644

Authors: L. Doubrawa, R.E.G. Machado, T.F. Laganá, G.B. Lima Neto, R. Monteiro-Oliveira, E.S. Cypriano

Comments: 13 pages, 11 figures, 2 tables. Accepted for publication in MNRAS in 2020 April 16

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

Collision events lead to peculiar morphologies in the intracluster gas of galaxies clusters. That seems to be the case of Abell 1644, a nearby galaxy cluster, composed of three main structures: the southern cluster that exhibits a spiral-like morphology, A1644S; the northern cluster seen in X-ray observations, A1644N1; and the recently discovered substructure, A1644N2. By means of $N$-body hydrodynamical simulations, we attempt to reconstruct the dynamical history of this system. These simulations resulted in two specific scenarios: (i) The collision between A1644S and A1644N2. Our best model has an inclination between the merger plane and the plane of the sky of $30^\circ$, and reaches the best morphology $1.6\,$Gyr after the pericentric passage. At this instant A1644N2 is gas poor, becoming nearly undetectable in X-ray emission. This model shows a good agreement with observations; (ii) The collision between A1644S and A1644N1. This approach did not give rise to results as satisfactory as the first scenario, due to great disturbances in density and mismatching temperature maps. As a complementary study, we perform a three-cluster simulation using as base the best-fitting model to reproduce the current state of A1644 with the three main structures. This scenario presented a good agreement to the global morphology of the observations. Thus, we find that the more likely scenario is a collision between A1644S and the newly discovered A1644N2, where A1644N1 may be present as long as it does not greatly interfere in the formation of the spiral feature.

[56]  arXiv:2004.13662 [pdf, other]

Title: Revising the merger scenario of the galaxy cluster Abell 1644: a new gas poor structure discovered by weak gravitational lensing

Authors: R. Monteiro-Oliveira, L. Doubrawa, R. E. G. Machado, G. B. Lima Neto, M. Castejon, E. S. Cypriano

Comments: 16 pages, 11 figures, 8 tables. Accepted for publication in MNRAS in 2020 April 27

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

The galaxy cluster Abell 1644 ($\bar{z}=0.047$) is known for its remarkable spiral-like X-ray emission. It was previously identified as a bimodal system, comprising the subclusters, A1644S and A1644N, each one centered on a giant elliptical galaxy. In this work, we present a comprehensive study of this system, including new weak-lensing and dynamical data and analysis plus a tailor-made hydrodynamical simulation. The lensing and galaxy density maps showed a structure in the North that could not be seen on the X-ray images. We, therefore, rename the previously known northern halo as A1644N1 and the new one as A1644N2. Our lensing data suggests that those have fairly similar masses: $M_{200}^{\rm N1}=0.90_{-0.85}^{+0.45} \times10^{14}$ and $M_{200}^{\rm N2}=0.76_{-0.75}^{+0.37} \times10^{14}$ M$_\odot$, whereas the southern structure is the main one: $M_{200}^{\rm S}=1.90_{-1.28}^{+0.89}\times 10^{14}$ M$_\odot$. Based on the simulations, fed by the observational data, we propose a scenario where the remarkable X-ray characteristics in the system are the result of a collision between A1644S and A1644N2 that happened $\sim$1.6 Gyr ago. Currently, those systems should be heading to a new encounter, after reaching their maximum separation.

[57]  arXiv:2004.13666 [pdf, other]

Title: Investigating surface correction relations for RGB stars

Authors: Andreas Christ Sølvsten Jørgensen, Josefina Montalbán, Andrea Miglio, Ben M. Rendle, Guy R. Davies, Gaël Buldgen, Richard Scuflaire, Arlette Noels, Patrick Gaulme, Rafael A. García

Comments: Submitted to MNRAS

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

State-of-the-art stellar structure and evolution codes fail to adequately describe turbulent convection. For stars with convective envelopes, such as red giants, this leads to an incomplete depiction of the surface layers. As a result, the predicted stellar oscillation frequencies are haunted by systematic errors, the so-called surface effect. Different empirically and theoretically motivated correction relations have been proposed to deal with this issue. In this paper, we compare the performance of these surface correction relations for red giant branch stars. For this purpose, we apply the different surface correction relations in asteroseismic analyses of eclipsing binaries and open clusters. In accordance with previous studies of main-sequence stars, we find that the use of different surface correction relations biases the derived global stellar properties, including stellar age, mass, and distance estimates. We furthermore demonstrate that the different relations lead to the same systematic errors for two different open clusters. Our results overall discourage from the use of surface correction relations that rely on reference stars to calibrate free parameters. Due to the demonstrated systematic biasing of the results, the use of appropriate surface correction relations is imperative to any asteroseismic analysis of red giants. Accurate mass, age, and distance estimates for red giants are fundamental when addressing questions that deal with the chemo-dynamical evolution of the Milky Way galaxy. In this way, our results also have implications for fields, such as galactic archaeology, that draw on findings from stellar physics.

[58]  arXiv:2004.13677 [pdf, other]

Title: Charged Dark Matter and the $H_0$ tension

Authors: Jose Beltrán Jiménez, Dario Bettoni, Philippe Brax

Comments: 27 pages, 14 figures, 2 animations (playable with Adobe Reader)

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

We consider cosmological models where dark matter is charged under a dark Abelian gauge field. This new interaction is repulsive and competes with gravity on large scales and in the dynamics of galaxies and clusters. We focus on non-linear models of dark electrodynamics where the effects of the new force are screened within a K-mouflage radius that helps avoiding traditional constraints on charged dark matter models. We discuss the background cosmology of these models in a Newtonian approach and show the equivalence with relativistic Lema\^itre models where an inhomogeneous pressure due to the electrostatic interaction is present. In particular, we find that dark matter shells of different radii evolve differently as they exit their K-mouflage radii at different times, resulting in a breaking of the initial comoving evolution. In the large time regime, the background cosmology is described by comoving but inhomogeneous model with a reduced gravitational Newton constant and a negative curvature originating from the electrostatic pressure. Baryons do not directly feel the electrostatic interaction, but are influenced by the inhomogeneous matter distribution induced by the electric force. We find that shells of smaller radii evolve faster than the outer shells which feel the repulsive interaction earlier. This mimics the discrepancy between the large scale Hubble rate and the local one. Similarly, as galaxies and clusters are not screened by the new interaction, large scale global flows would result from the existence of the new dark electromagnetic interaction.

[59]  arXiv:2004.13679 [pdf, other]

Title: Aluminium oxide in the atmosphere of hot Jupiter WASP-43b

Authors: Katy L. Chubb, Michiel Min, Yui Kawashima, Christiane Helling, Ingo Waldmann

Comments: Accepted for publication in A&A. 16 pages, 7 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)

We have conducted a re-analysis of publicly available Hubble Space Telescope Wide Field Camera 3 (HST WFC3) transmission data for the hot-Jupiter exoplanet WASP-43b, using the Bayesian retrieval package Tau-REx. We report evidence of AlO in transmission to a high level of statistical significance (> 5-sigma in comparison to a flat model, and 3.4-sigma in comparison to a model with H2O only). We find no evidence of the presence of CO, CO2, or CH4 based on the available HST WFC3 data or on Spitzer IRAC data. We demonstrate that AlO is the molecule that fits the data to the highest level of confidence out of all molecules for which high-temperature opacity data currently exists in the infrared region covered by the HST WFC3 instrument, and that the subsequent inclusion of Spitzer IRAC data points in our retrieval further supports the presence of AlO. H2O is the only other molecule we find to be statistically significant in this region. AlO is not expected from the equilibrium chemistry at the temperatures and pressures of the atmospheric layer that is being probed by the observed data. Its presence therefore implies direct evidence of some disequilibrium processes with links to atmospheric dynamics. Implications for future study using instruments such as the James Webb Space Telescope (JWST) are discussed, along with future opacity needs. Comparisons are made with previous studies into WASP-43b.

[60]  arXiv:2004.13707 [pdf, other]

Title: Three-dimensional analysis of the Minispiral at the Galactic Center: orbital parameters, periods and the mass of the black hole

Authors: Maria Selina Nitschai, Nadine Neumayer, Anja Feldmeier-Krause

Comments: 14 pages, 12 figures, 2 tables. Accepted for publication in ApJ

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

In this paper we simultaneously fit the orbits and line-of-sight velocities of the ionized gas around the supermassive black hole, Sagittarius A$^{\ast}$ (Sgr A$^{\ast}$), at the center of the Milky Way. The data we use are taken with the K-band Multi Object Spectrograph (KMOS), presented in Feldmeier-Krause et al. (2015) and cover the central $\sim$ 2 pc of the Milky Way. From the brightest gas emission line in the K-band, the Br$\gamma$ line, we derive the spatial distribution and line-of-sight velocities of the gas in the minispiral. Using the flux distribution and the line-of-sight velocity information, we perform a fit to the three main gas streamers in the minispiral, the Northern Arm, Eastern Arm, and Western Arc, using a Bayesian modelling method, and are able to reconstruct the three-dimensional orbits of these gas streamers. With the best fit orbital parameters and the measured line-of-sight velocities, we constrain the mass of Sgr A$^{\ast}$. The orbit of the Eastern Arm is the one that is best constrained using our data. It gives a best-fit orbital period of $17.4_{-11.6}^{+31.0}\cdot 10^3$ years and results in an enclosed mass of $14.9_{-10.4}^{+69.4}\cdot 10^6 M_{\odot}.$

Cross-lists for Wed, 29 Apr 20

[61]  arXiv:2003.07463 (cross-list from gr-qc) [pdf, other]

Title: Cosmological bounces, cyclic universes, and effective cosmological constant in Einstein-Cartan-Dirac-Maxwell theory

Authors: Francisco Cabral, Francisco S. N. Lobo, Diego Rubiera-Garcia

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

Einstein-Cartan theory is an extension of the standard formulation of General Relativity characterized by a non-vanishing torsion. The latter is sourced by the matter fields via the spin tensor, and its effects are expected to be important at very high spin densities. In this work we analyze in detail the physics of Einstein-Cartan theory with Dirac and Maxwell fields minimally coupled to the spacetime torsion. This breaks the $U(1)$ gauge symmetry, which is suggested by the possibility of a torsion-induced phase transition in the early Universe. The resulting Dirac-like and Maxwell-like equations are non-linear with self-interactions as well as having fermion-boson non-minimal couplings. We discuss several cosmological aspects of this theory, including bounces, acceleration phases and matter-antimatter asymmetry in the torsion era, as well as late-time effects such as the generation of an effective cosmological constant, dark energy, and future bounces within cyclic solutions.

[62]  arXiv:2004.11619 (cross-list from hep-th) [pdf, other]

Title: Degeneracy, matter coupling, and disformal transformations in scalar-tensor theories

Authors: Cédric Deffayet, Sebastian Garcia-Saenz

Comments: 37 pages

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

Degenerate scalar-tensor theories of gravity extend general relativity by a single degree of freedom, despite their equations of motion being higher than second order. In some cases, this is a mere consequence of a disformal field redefinition carried out in a non-degenerate theory. More generally, this is made possible by the existence of an additional constraint that removes the would-be ghost. It has been noted that this constraint can be thwarted when the coupling to matter involves time derivatives of the metric, which results in a modification of the canonical momenta of the gravitational sector. In this note we expand on this issue by analyzing the precise ways in which the extra degree of freedom may reappear upon minimal coupling to matter. Specifically, we study examples of matter sectors that lead either to a direct loss of the special constraint or to a failure to generate a pair of secondary constraints. We also discuss the recurrence of the extra degree of freedom using the language of disformal transformations in particular for what concerns "veiled" gravity. On the positive side, we show that the minimal coupling of spinor fields is healthy and does not spoil the additional constraint. We argue that this virtue of spinor fields to preserve the number of degrees of freedom in the presence of higher derivatives is actually very general and can be seen from the level decomposition of Grassmann-valued classical variables.

[63]  arXiv:2004.13039 (cross-list from hep-ph) [pdf, other]

Title: The Hubble tension and a renormalizable model of gauged neutrino self-interactions

Authors: Maximilian Berbig, Sudip Jana, Andreas Trautner

Comments: 9 pages, 2 figures, 1 table

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

We present a simple extension of the Standard Model that leads to renormalizable long-range vector-mediated neutrino self-interactions. This model can resolve the Hubble tension by delaying the onset of neutrino free-streaming during recombination, without conflicting with other measurements. The extended gauge, scalar and neutrino sectors lead to observable signatures, including invisible Higgs and $Z$ decays, thereby relating the Hubble tension to precision measurements at the LHC and future colliders. The model has a new neutrinophilic gauge boson with $m_{Z'}\sim\mathcal{O}(10~\mathrm{eV})$ and charged Higgses at a few $100~\mathrm{GeV}$. It requires hidden neutrinos with active-hidden mixing angles larger than $5\times10^{-4}$ and masses in the range $1\div300\mathrm{eV}$, which could also play a role for short baseline neutrino oscillation anomalies.

[64]  arXiv:2004.13051 (cross-list from gr-qc) [pdf, ps, other]

Title: Cosmological gravity on all scales: simple equations, required conditions, and a framework for modified gravity

Authors: Daniel B Thomas

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

The cosmological phenomenology of gravity is typically studied in two limits: relativistic perturbation theory (on large scales) and Newtonian gravity (required for smaller, non-linear, scales). Traditional approaches to model-independent modified gravity are based on perturbation theory, so do not apply on non-linear scales. Future surveys such as Euclid will produce significant data on both linear and non-linear scales, so a new approach is required to constrain model-independent modified gravity by simultaneously using all of the data from these surveys. We use the higher order equations from the post-Friedmann approach to derive a single set of "simple 1PF" (first post-Friedmann) equations that apply in both the small scale and large scale limits, and we examine the required conditions for there to be no intermediate regime, meaning that these simple equations are valid on all scales. We demonstrate how the simple 1PF equations derived here can be used as a model-independent framework for modified gravity that applies on all cosmological scales, and we present an algorithm for determining which modified gravity theories are subsumed under this approach. This modified gravity framework provides a rigorous approach to phenomenological N-body simulations, and paves the way to consistently using all of the data from upcoming surveys to constrain modified gravity in a model-independent fashion.

[65]  arXiv:2004.13061 (cross-list from gr-qc) [pdf, other]

Title: A consistent model of non-singular Schwarzschild black hole in loop quantum gravity and its quasinormal modes

Authors: Mariam Bouhmadi-López, Suddhasattwa Brahma, Che-Yu Chen, Pisin Chen, Dong-han Yeom

Comments: 18 pages, 9 figures

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

We investigate the interior structure, perturbations, and the associated quasinormal modes of a quantum black hole model recently proposed by Bodendorfer, Mele, and M\"unch (BMM). Within the framework of loop quantum gravity, the quantum parameters in the BMM model are introduced through polymerization, consequently replacing the Schwarzschild singularity with a spacelike transition surface. By treating the quantum geometry corrections as an `effective' matter contribution, we first prove the violation of energy conditions (in particular the null energy condition) near the transition surface and then investigate the required junction conditions on it. In addition, we study the quasinormal modes of massless scalar field perturbations, electromagnetic perturbations, and axial gravitational perturbations in this effective model. As expected, the quasinormal spectra deviate from their classical counterparts in the presence of quantum corrections. Interestingly, we find that the quasinormal frequencies of perturbations with different spins share the same qualitative tendency with respect to the change of the quantum parameters in this model.

[66]  arXiv:2004.13100 (cross-list from gr-qc) [pdf, ps, other]

Title: The role of the slope in the the multi-measure cosmological model

Authors: Denitsa Staicova

Comments: 11 pages, 4 figures, Contribution to XIII-th International Workshop "Lie Theory and Its Applications in Physics", Varna (2019);

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

In this work, we report some results on the numerical exploration of the model of Guendelman-Nissimov-Pacheva. This model has been previously applied to cosmology, but there were open questions regarding its parameters. Here we demonstrate the existence of families of solutions on the slope of the effective potential which preserve the duration of the inflation and its power. For this solutions, one can see the previously reported phenomenon of the inflaton scalar field climbing up the slope, with the effect more pronounced when starting lower on the potential slope. Finally we compare the dynamical and the potential slow-roll parameters for the model and we find that the latter describe the numerically observed inflationary period better.

[67]  arXiv:2004.13163 (cross-list from gr-qc) [pdf, ps, other]

Title: The Spin Tensor of Dark Matter and the Hubble Parameter Tension

Authors: Fernando Izaurieta, Samuel Lepe, Omar Valdivia

Comments: 6 pages, no figures

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

Allowing for a nonvanishing spin tensor for cold dark matter ($\omega_{\mathrm{DM}}=0$) has the consequence of giving rise to an effective $\mathrm{FLRW}$ dynamics with a small negative barotropic constant for an effective dark matter density ($-1/3<\omega_{\mathrm{eff}}\leq0$). This turns out to solve the Hubble parameter tension in a straightforward way.

[68]  arXiv:2004.13280 (cross-list from physics.ins-det) [pdf]

Title: A facility for mass production of ultra-pure NaI powder for the COSINE-200 experiment

Authors: Keonah Shin, Junseok Choe, Olga Gileva, Alain Iltis, Yeongduk Kim, Cheolho Lee, Hyun Su Lee, Moo Hyun Lee, Hyang Kyu Park

Comments: Proceeding for INSTR20

Subjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex)

COSINE-200 is the next phase of the ongoing COSINE-100 experiment. The main purpose of the experiment is the performance of an unambiguous verification of the annual modulation signals observed by the DAMA experiment. The success of the experiment critically depends on the production of a 200 kg array of ultra-pure NaI(Tl) crystal detectors that have lower backgrounds than the DAMA crystals. The purification of raw powder is the initial but important step toward the production of ultra-pure NaI(Tl) detectors. We have already demonstrated that fractional recrystallization from water solutions is an effective method for the removal of the problematic K and Pb elements. For the mass production of purified powder, a clean facility for the fractional recrystallization had been constructed at the Institute for Basic Science (IBS), Korea. Here, we report the design of the purification process, material recovery, and performance of the NaI powder purification facility.

[69]  arXiv:2004.13296 (cross-list from physics.ins-det) [pdf, other]

Title: Observation of primary scintillations in the visible range in liquid argon doped with methane

Authors: A. Bondar, E. Borisova, A. Buzulutskov, E. Frolov, V. Nosov, V. Oleynikov, A. Sokolov

Comments: 10 pages, 6 figures. Presented at Instrumentation for Colliding Beam Physics Conference (INSTR20)

Subjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex)

Neutron veto detector based on liquid scintillator containing hydrogen atoms is an integral part of any underground experiment for dark matter search. So far, a flammable mixture of liquid hydrocarbons was used as a liquid scintillator in such detectors. A safe alternative might be a liquid scintillator based on liquid argon doped with methane. In this work, we have studied the primary scintillations in pure liquid argon and its mixtures with methane, the CH4 content varying from 100 ppm to 5%. The primary scintillations have for the first time been observed in liquid argon doped with methane, in the visible and near infrared range, and their relative light yields have been measured as a function of the CH4 content.

[70]  arXiv:2004.13308 (cross-list from hep-ph) [pdf, ps, other]

Title: Photon directional profile from stimulated decay of axion clouds with arbitrary axion spatial distributions

Authors: Liang Chen, Thomas W. Kephart

Comments: 8 pages

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

We model clusters of axions with spherically symmetric momentum but arbitrary spatial distributions and study the directional profile of photos produced in their evolution through spontaneous and stimulated decay of axions via the process $a \rightarrow \gamma + \gamma$. Several specific examples are presented.

[71]  arXiv:2004.13355 (cross-list from physics.ins-det) [pdf, other]

Title: Observation of unusual slow components in electroluminescence signal of two-phase argon detector

Authors: A. Bondar, E. Borisova, A. Buzulutskov, E. Frolov, V. Oleynikov, A. Sokolov

Comments: 17 pages, 14 figures, 1 equation. Proceedings paper of the INSTR20 conference

Subjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex)

Proportional electroluminescence (EL) in noble gases is used in two-phase detectors for dark matter search to record ionization signals in the gas phase induced by particle scattering in the liquid phase (S2 signals). In this work, the EL pulse-shapes in a two-phase argon detector have for the first time been studied systematically in a wide range of reduced electric field, varying from 3 to 9 Td. The pulse-shapes were studied at different readout configurations and spectral ranges: using cryogenic PMTs and SiPMs, with and without a wavelength shifter (WLS), in the VUV and visible range. We observed the fast component and two unusual slow components, with time constants of about 5 $\mu$s and 40 $\mu$s. The unusual characteristic property of slow components was that their contribution and time constants increased with electric field.

[72]  arXiv:2004.13430 (cross-list from physics.space-ph) [pdf, other]

Title: Visualizing and Interpreting Unsupervised Solar Wind Classifications

Authors: Jorge Amaya (1), Romain Dupuis (1), Maria Elena Innocenti (2), Giovanni Lapenta (1) ((1) Centre for mathematical Plasma-Astrophysics, CmPA, Mathematics Department, KU Leuven, University of Leuven, Belgium, (2) Jet Propulsion Laboratory, Interstellar and Heliospheric Physics Division, Pasadena, CA, USA)

Comments: Submitted to: Frontiers in Astronomy and Space Sciences, Space Physics, Research Topic Machine Learning in Heliophysics

Subjects: Space Physics (physics.space-ph); Solar and Stellar Astrophysics (astro-ph.SR)

One of the goals of machine learning is to eliminate tedious and arduous repetitive work. The manual and semi-automatic classification of millions of hours of solar wind data from multiple missions can be replaced by automatic algorithms that can discover, in mountains of multi-dimensional data, the real differences in the solar wind properties. In this paper we present how unsupervised clustering techniques can be used to segregate different types of solar wind. We propose the use of advanced data reduction methods to pre-process the data, and we introduce the use of Self-Organizing Maps to visualize and interpret 14 years of ACE data. Finally, we show how these techniques can potentially be used to uncover hidden information, and how they compare with previous manual and automatic categorizations.

[73]  arXiv:2004.13461 (cross-list from math.NA) [pdf, ps, other]

Title: Phase reconstruction with iterated Hilbert transforms

Authors: Erik Gengel, Arkady Pikovsky

Comments: The manuscript is based on findings presented in the poster presentation at the Dynamics days Europe in 2019

Subjects: Numerical Analysis (math.NA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Chaotic Dynamics (nlin.CD); Data Analysis, Statistics and Probability (physics.data-an)

We present a study dealing with a novel phase reconstruction method based on iterated Hilbert transform embeddings. We show results for the Stuart-Landau oscillator observed by generic observables. The benefits for reconstruction of the phase response curve a presented and the method is applied in a setting where the observed system is pertubred by noise.

[74]  arXiv:2004.13589 (cross-list from physics.atom-ph) [pdf, other]

Title: Opacity modelling of heavy-metal hot subdwarfs. Photoionization of Sr$^0$, Y$^{+}$ and Zr$^{2+}$

Authors: L. Fernández-Menchero, C. S. Jeffery, C. A. Ramsbottom, C. P. Ballance

Comments: 8 pages, 6 figures, 6 tables

Subjects: Atomic Physics (physics.atom-ph); Solar and Stellar Astrophysics (astro-ph.SR)

Heavy-metal hot subdwarfs (sdB and sdO) represent a small group of stars with unusually high concentrations of trans-iron elements in their atmospheres, having abundances ~ 10000 times solar. One example is LS IV-14$^{\circ}$ 116, where a number of heavy-metal absorption lines of Sr II, Y III and Zr IV have been observed in the optical band 4000 - 5000 A. We use a fully relativistic Dirac atomic R-Matrix (DARC) to calculate photoionization cross sections of Sr$^{0}$, Y$^{+}$ and Zr$^{2+}$ from their ground state to the twentieth excited level. We use the cross sections and the oscillator strengths to simulate the spectrum of a hot subdwarf. We obtain complete sets of photoionization cross sections for the three ions under study. We use these data to calculate the opacity of the stellar atmospheres of hot subdwarf stars, and show that for overabundances observed in some heavy-metal subdwarves, photo-excitation from zirconium, in particular, does contribute some back warming in the model.

[75]  arXiv:2004.13698 (cross-list from physics.plasm-ph) [pdf, other]

Title: Carbon ionization at Gbar pressures: an ab initio perspective on astrophysical high-density plasmas

Authors: Mandy Bethkenhagen, Bastian B. L. Witte, Maximilian Schörner, Gerd Röpke, Tilo Döppner, Dominik Kraus, Siegfried H. Glenzer, Philip A. Sterne, Ronald Redmer

Comments: accepted for publication in Physical Review Research

Subjects: Plasma Physics (physics.plasm-ph); Solar and Stellar Astrophysics (astro-ph.SR); Computational Physics (physics.comp-ph)

A realistic description of partially-ionized matter in extreme thermodynamic states is critical to model the interior and evolution of the multiplicity of high-density astrophysical objects. Current predictions of its essential property, the ionization degree, rely widely on analytical approximations that have been challenged recently by a series of experiments. Here, we propose a novel ab initio approach to calculate the ionization degree directly from the dynamic electrical conductivity using the Thomas-Reiche-Kuhn sum rule. This Density Functional Theory framework captures genuinely the condensed matter nature and quantum effects typical for strongly-correlated plasmas. We demonstrate this new capability for carbon and hydrocarbon, which most notably serve as ablator materials in inertial confinement fusion experiments aiming at recreating stellar conditions. We find a significantly higher carbon ionization degree than predicted by commonly used models, yet validating the qualitative behavior of the average atom model Purgatorio. Additionally, we find the carbon ionization state to remain unchanged in the environment of fully-ionized hydrogen. Our results will not only serve as benchmark for traditional models, but more importantly provide an experimentally accessible quantity in the form of the electrical conductivity.

Replacements for Wed, 29 Apr 20

[76]  arXiv:1809.00995 (replaced) [pdf, other]

Title: Abelian-Higgs Cosmic String Evolution with CUDA

Authors: J. R. C. C. C. Correia, C. J. A. P. Martins

Comments: 18 pages, 4 figures; substantially extended version, to appear in Astronomy and Computing

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

[77]  arXiv:1810.01857 (replaced) [pdf, other]

Title: The Interplay of Kinetic and Radiative Feedback in Galaxy Clusters

Authors: Yu Qiu (1), Tamara Bogdanovic (1), Yuan Li (2,3), KwangHo Park (1), John H. Wise (1) ((1) Georgia Institute of Technology, (2) Flatiron Institute, (3) University of California, Berkeley)

Comments: Published in ApJ (28 pages, 14 figures)

Journal-ref: Qiu et al. 2019, ApJ, 877, 47

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

[78]  arXiv:1901.06269 (replaced) [pdf, other]

Title: A kilonova associated with GRB 070809

Authors: Zhi-Ping Jin, Stefano Covino, Neng-Hui Liao, Xiang Li, Paolo D'Avanzo, Yi-Zhong Fan, Da-Ming Wei

Comments: 20 pages, 5 figures, published in Nature Astronomy

Journal-ref: Nat. Astron. 4, 77-82 (2020)

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

[79]  arXiv:1903.07092 (replaced) [pdf, other]

Title: Lunar Laser Ranging constraints on nonminimally coupled dark energy and standard sirens

Authors: Shinji Tsujikawa

Comments: 18 pages, 9 figures

Journal-ref: Phys. Rev. D 100, 043510 (2019)

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

[80]  arXiv:1904.08427 (replaced) [pdf, ps, other]

Title: Towards an accurate description of an accretion induced collapse and the associated ejected mass

Authors: Amir Sharon, Doron Kushnir

Comments: Accepted for publication in ApJ, 15 pages, 9 figures

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

[81]  arXiv:1904.11980 (replaced) [pdf, other]

Title: Forecasting Interacting Vacuum-Energy Models using Gravitational Waves

Authors: Weiqiang Yang, Supriya Pan, Eleonora Di Valentino, Bin Wang, Anzhong Wang

Comments: 19 pages, 9 figures, and 5 tables; version accepted for publication by JCAP

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

[82]  arXiv:1907.05163 (replaced) [pdf, other]

Title: On simple analytic models of microlensing amplification statistics

Authors: Pierre Fleury, Juan García-Bellido

Comments: 16+3 pages, 16 figures. v2: added section on extended sources; matches published version in Physics of the Dark Universe

Journal-ref: Physics of the Dak Universe (2020) 100567

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

[83]  arXiv:1908.01799 (replaced) [pdf, other]

Title: Emission Signatures from Sub-parsec Binary Supermassive Black Holes III: Comparison of Models with Observations

Authors: Khai Nguyen (1), Tamara Bogdanovic (1), Jessie C. Runnoe (2, 3), Michael Eracleous (4), Steinn Sigurdsson (4), Todd Boroson (5) ((1) Georgia Institute of Technology, (2) University of Michigan, (3) Vanderbilt University, (4) Pennsylvania State University, (5) Las Cumbres Observatory)

Comments: Accepted to ApJ (31 pages, 19 figures), includes referee's comments

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

[84]  arXiv:1908.03353 (replaced) [pdf, other]

Title: Probing Massive Scalar Fields from a Pulsar in a Stellar Triple System

Authors: Brian C. Seymour, Kent Yagi

Comments: 5 figures, 14 pages

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

[85]  arXiv:1909.08202 (replaced) [pdf, other]

Title: Rapid and efficient mass collection by a supersonic cloud-cloud collision as a major mechanism of high-mass star formation

Authors: Yasuo Fukui, Tsuyoshi Inoue, Takahiro Hayakawa, Kazufumi Torii

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

[86]  arXiv:1910.00602 (replaced) [pdf, other]

Title: X-ray Observations of Luminous Dusty Quasars at z > 2

Authors: G. B. Lansbury, M. Banerji, A. C. Fabian, M. J. Temple

Comments: In press. Accepted for publication in MNRAS

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

[87]  arXiv:1910.00717 (replaced) [pdf, other]

Title: Probing multi-step electroweak phase transition with multi-peaked primordial gravitational waves spectra

Authors: António P. Morais, Roman Pasechnik

Comments: 33 pages, 7 figures; references added; discussion of the results updated; published version

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

[88]  arXiv:1910.02962 (replaced) [pdf, other]

Title: 3D Distribution Map of HI Gas and Galaxies Around an Enormous Ly$α$ Nebula and Three QSOs at $z=2.3$ Revealed by the HI Tomographic Mapping Technique

Authors: Shiro Mukae, Masami Ouchi, Zheng Cai, Khee-Gan Lee, J. Xavier Prochaska, Sebastiano Cantalupo, Zheng Zheng, Kentaro Nagamine, Nao Suzuki, John D. Silverman, Toru Misawa, Akio K. Inoue, Joseph F. Hennawi, Yuichi Matsuda, Ken Mawatari, Yuma Sugahara, Takashi Kojima, Yoshiaki Ono, Takatoshi Shibuya, Yuichi Harikane, Seiji Fujimoto, Yi-Kuan Chiang, Haibin Zhang, Ryota Kakuma

Comments: 15 pages, 9 figures. Accepted for Publication in ApJ

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

[89]  arXiv:1910.07529 (replaced) [pdf, other]

Title: A Tip of the Red Giant Branch Distance to the Dark Matter Deficient Galaxy NGC1052-DF4 from Deep Hubble Space Telescope Data

Authors: Shany Danieli, Pieter van Dokkum, Roberto Abraham, Charlie Conroy, Andrew E. Dolphin, Aaron J. Romanowsky

Comments: Accepted for publication in ApJ Letters, in press. Figure 1 shows the color image of the galaxy. The main result is shown in Figure 4

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

[90]  arXiv:1910.08068 (replaced) [pdf, other]

Title: Baryogenesis from a dark first-order phase transition

Authors: Eleanor Hall, Thomas Konstandin, Robert McGehee, Hitoshi Murayama, Géraldine Servant

Comments: 11+3 pages, 3 figures; v2: published in JHEP with minor revisions (no change to results)

Journal-ref: JHEP 04 (2020) 042

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

[91]  arXiv:1910.09456 (replaced) [pdf, other]

Title: Analysis of the H.E.S.S. public data release with ctools

Authors: Jürgen Knödlseder, Luigi Tibaldo, Domenico Tiziani, Andreas Specovius, Josh Cardenzana, Michael Mayer, Nathan Kelley-Hoskins, Leonardo Di Venere, Simon Bonnefoy, Andreas Ziegler, Stefan Eschbach, Pierrick Martin, Thierry Louge, Francois Brun, Maria Haupt, Rolf Bühler

Comments: 34 pages, 47 figures

Journal-ref: A&A 632, A102 (2019)

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

[92]  arXiv:1911.00116 (replaced) [pdf, other]

Title: A Machine Learning Based Source Property Inference for Compact Binary Mergers

Authors: Deep Chatterjee, Shaon Ghosh, Patrick R. Brady, Shasvath J. Kapadia, Andrew L. Miller, Samaya Nissanke, Francesco Pannarale

Comments: accepted in ApJ

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

[93]  arXiv:1911.01434 (replaced) [pdf, other]

Title: Binary black holes in the pair-instability mass gap

Authors: Ugo N. Di Carlo, Michela Mapelli, Yann Bouffanais, Nicola Giacobbo, Filippo Santoliquido, Sandro Bressan, Mario Spera, Francesco Haardt

Comments: 7 pages, 3 figures, 1 table, resubmitted to MNRAS after addressing referee's comments

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

[94]  arXiv:1911.05973 (replaced) [pdf, other]

Title: Testing kinetically coupled inflation models with CMB distortions

Authors: Rui Dai, Yi Zhu

Comments: 18 pages, 16 figures, to be published in JCAP

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

[95]  arXiv:1911.09116 (replaced) [pdf, other]

Title: Baryonic clues to the puzzling diversity of dwarf galaxy rotation curves

Authors: Isabel M.E. Santos-Santos, Julio F. Navarro, Andrew Robertson, Alejandro Benítez-Llambay, Kyle A. Oman, Mark R. Lovell, Carlos S. Frenk, Aaron D. Ludlow, Azadeh Fattahi, Adam Ritz

Comments: 20 pages, 16 figures, 1 table. Accepted for publication in MNRAS. Updated acknowledgements

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

[96]  arXiv:1912.07467 (replaced) [pdf, other]

Title: PSR J0030+0451, GW170817 and the nuclear data: joint constraints on equation of state and bulk properties of neutron stars

Authors: Jin-Liang Jiang, Shao-Peng Tang, Yuan-Zhu Wang, Yi-Zhong Fan, Da-Ming Wei

Comments: 9 pages, 3 figures, 2 tables, ApJ accepted

Journal-ref: 2020, ApJ, 892, 1

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

[97]  arXiv:2001.03859 (replaced) [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: version accepted for publication in Physical Review C

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

[98]  arXiv:2001.04681 (replaced) [pdf, other]

Title: Revisiting old (AGN) friends -- what's changed in their spectral looks

Authors: Hartmut Winkler

Comments: submitted for publication in the Proceedings of IAU Symposium 356, Nuclear Activity in Galaxies across Cosmic Time, Addis Ababa, Ethiopia, Oct 2019

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

[99]  arXiv:2001.06904 (replaced) [pdf, other]

Title: UV & U-band luminosity functions from CLAUDS and HSC-SSP -- I. Using four million galaxies to simultaneously constrain the very faint and bright regimes to $z \sim 3$

Authors: Thibaud Moutard, Marcin Sawicki, Stéphane Arnouts, Anneya Golob, Jean Coupon, Olivier Ilbert, Xiaohu Yang, Stephen Gwyn

Comments: 18 pages, 11 figures (26 pages, 18 figures including the Appendix). Accepted for publication in MNRAS. Version to be published

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

[100]  arXiv:2002.02420 (replaced) [pdf, other]

Title: Initial conditions for plateau inflation: a case study

Authors: Tommi Tenkanen, Eemeli Tomberg

Comments: 16 pages, 6 figures. v2: A slight change of title, discussion and references added. Matches the version published in JCAP

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

[101]  arXiv:2002.05073 (replaced) [pdf, other]

Title: Jet-shaped geometrically modified light curves of core collapse supernovae

Authors: Noa Kaplan, Noam Soker (Technion, Israel)

Comments: Accepted for publication in MNRAS

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

[102]  arXiv:2002.10605 (replaced) [pdf, ps, other]

Title: Determining $H_0$ Model-Independently and Consistency Tests

Authors: Kai Liao, Arman Shafieloo, Ryan E. Keeley, Eric V. Linder

Comments: 9 pages, 6 figures, 3 tables, to appear in The Astrophysical Journal Letters

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

[103]  arXiv:2002.12369 (replaced) [pdf, ps, other]

Title: The Curious Case of PHL 293B: A Long-Lived Transient in a Metal-Poor Blue Compact Dwarf Galaxy

Authors: Colin J. Burke, Vivienne F. Baldassare, Xin Liu, Ryan J. Foley, Yue Shen, Antonella Palmese, Hengxiao Guo, Kenneth Herner, Tim M. C. Abbott, Michel Aguena, Sahar Allam, Santiago Avila, Emmanuel Bertin, David Brooks, Aurelio Carnero Rosell, Matias Carrasco Kind, Jorge Carretero, Luiz N. da Costa, Juan De Vicente, Shantanu Desai, Peter Doel, Tim F. Eifler, Spencer Everett, Josh Frieman, Juan Garcia-Bellido, Enrique Gaztanaga, Daniel Gruen, Robert A. Gruendl, Julia Gschwend, Gaston Gutierrez, Devon L. Hollowood, Klaus Honscheid, David J. James, Elisabeth Krause, Kyler Kuehn, Marcio A. G. Maia, Felipe Menanteau, Ramon Miquel, Francisco Paz-Chinchon, Andres A. Plazas, Eusebio Sanchez, Basilio Santiago, Vic Scarpine, Santiago Serrano, Ignacio Sevilla-Noarbe, Mathew Smith, Marcelle Soares-Santos, et al. (7 additional authors not shown)

Comments: 15 pages, 6 figures, 1 table. Accepted for publication in ApJ Letters

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

[104]  arXiv:2002.12384 (replaced) [pdf, other]

Title: Intermittent hydrodynamic jets in collapsars do not produce GRBs

Authors: Ore Gottlieb, Amir Levinson, Ehud Nakar

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

[105]  arXiv:2003.01823 (replaced) [pdf]

Title: A New Approach to Solar Flare Prediction

Authors: Michael L. Goodman (1), Chiman Kwan (2), Bulent Ayhan (2), Eric L. Shang (2) ((1) Jacobs Space Exploration Group, NASA Marshall Space Flight Center, Huntsville, AL, (2) Applied Research LLC, Rockville, MD)

Comments: 37 pages, 15 figures. Corresponding author - Michael L. Goodman

Journal-ref: Frontiers of Physics 15(3), 34601 (2020)

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

[106]  arXiv:2003.08587 (replaced) [pdf, other]

Title: Local Molecular Gas toward the Aquila Rift Region

Authors: Yang Su, Ji Yang, Qing-zeng Yan, Yan Gong, Zhiwei Chen, Shaobo Zhang, Yan Sun, Miaomiao Zhang, Xuepeng Chen, Xin Zhou, Min Wang, Hongchi Wang, Ye Xu, Zhibo Jiang

Comments: 25 figures, 1 table, typos corrected

Journal-ref: The Astrophysical Journal, 893:91 (24pp), 2020 April 20

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

[107]  arXiv:2003.13476 (replaced) [pdf, other]

Title: Radio spectral properties and jet duty cycle in the restarted radio galaxy 3C388

Authors: M. Brienza, R. Morganti, J. Harwood, T. Duchet, K. Rajpurohit, A. Shulevski, M. J. Hardcastle, V. Mahatma, L. E. H. Godfrey, I. Prandoni, T. W. Shimwell, H. Intema

Comments: 14 pages, 10 figures, 4 tables, A&A accepted

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

[108]  arXiv:2004.09487 (replaced) [pdf, other]

Title: Relieving the Hubble tension with primordial magnetic fields

Authors: Karsten Jedamzik, Levon Pogosian

Comments: 8 pages (including supplemental material in the appendix), 3 figures, 1 table; minor corrections and references added

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

[109]  arXiv:2004.09515 (replaced) [pdf, other]

Title: The Effective Halo Model: Creating a Physical and Accurate Model of the Matter Power Spectrum and Cluster Counts

Authors: Oliver H. E. Philcox, David N. Spergel, Francisco Villaescusa-Navarro

Comments: 38 pages, 13 figures, submitted to Phys. Rev. D. Python package and tutorial available at this http URL

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)

[110]  arXiv:2004.09525 (replaced) [pdf, other]

Title: Binary black holes in young star clusters: the impact of metallicity

Authors: Ugo N. Di Carlo, Michela Mapelli, Nicola Giacobbo, Mario Spera, Yann Bouffanais, Sara Rastello, Filippo Santoliquido, Mario Pasquato, Alessandro Ballone, Alessandro A. Trani, Stefano Torniamenti, Francesco Haardt

Comments: 13 pages, 9 figures, 5 tables, submitted to MNRAS. Comments welcome

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

[111]  arXiv:2004.10770 (replaced) [pdf, other]

Title: Observations of Disequilibrium CO Chemistry in the Coldest Brown Dwarfs

Authors: Brittany E. Miles, Andrew J. I. Skemer, Caroline V. Morley, Mark S. Marley, Jonathan J. Fortney, Katelyn N. Allers, Jacqueline K. Faherty, Thomas R. Geballe, Channon Visscher, Adam C. Schneider, Roxana Lupu, Richard S. Freedman, Gordon L. Bjoraker

Comments: Accepted to the Astronomical Journal. 24 Pages, 16 Figures, 4 Tables. take care

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

[112]  arXiv:2004.11263 (replaced) [pdf, other]

Title: Chandra High Energy Transmission Gratings Spectra of V3890 Sgr

Authors: Marina Orio (INAF Padova, and U Wisconsin Madison), Jeremy J. Drake (CfA), Jan-Uwe Ness (XMM-ESAC), E. Behar (Technion), Gerardo Juan M. Luna (U Buenos Aires-IAFE and Hurlingham University), Matt J. Darnley (John Moores University), Jay Gallagher (U Wisconsin Madison), Robert D. Gehrz (U Minnesota), N. Paul M. Kuin (University College-London, Mullard Laboratory), Joanna Mikolajewska (CAMK), Nataly Ospina (U Padova), Kim L. Page (U Leicester), Rosa Poggiani (U Pisa and INFN-Pisa), Sumner Starrfield (Arizona State University), Robert Williams (U California-Santa Cruz and Hubble space Science Institute), Chuck E. Woodward (U Minnesota)

Comments: In press on the ApJ

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

[113]  arXiv:2004.11688 (replaced) [pdf, ps, other]

Title: Rotation Curve of the Milky Way and the Dark Matter Density

Authors: Yoshiaki Sofue

Comments: Invited review to appear in Galaxies, 28 pages, 4 figures, 8 tables

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

[114]  arXiv:2004.11895 (replaced) [pdf, other]

Title: Detecting scalar fields with Extreme Mass Ratio Inspirals

Authors: Andrea Maselli, Nicola Franchini, Leonardo Gualtieri, Thomas P. Sotiriou

Comments: Typos corrected

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

[115]  arXiv:2004.12128 (replaced) [pdf, ps, other]

Title: Astronomical Site Monitoring System at Lijiang Observatory

Authors: Yu-Xin Xin, Jin-Ming Bai, Bao-Li Lun, Yu-Feng Fan, Chuan-Jun Wang, Xiao-Wei Liu, Xiao-Guang Yu, Kai Ye, Teng-Fei Song, Liang Chang, Shou-Sheng He, Ji-Rong Mao, Liang Xu, Ding-Rong Xiong, Xi-Liang Zhang, Jian-Guo Wang, Xu Ding, Hai-Cheng Feng, Xiang-Kun Liu, Yang Huang, Bing-Qiu Chen

Comments: 21 pages,40 figures

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

[116]  arXiv:2004.12176 (replaced) [pdf, other]

Title: Measuring turbulent motion in planet-forming disks with ALMA: A detection around DM Tau and non-detections around MWC 480 and V4046 Sgr

Authors: Kevin Flaherty, A. Meredith Hughes, Jacob B. Simon, Chunhua Qi, Xue-ning Bai, Alyssa Bulatek, Sean M. Andrews, David J. Wilner, Agnes Kospal

Comments: 21 pages, 10 figures, accepted to ApJ

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

[117]  arXiv:2004.12272 (replaced) [pdf]

Title: Mass distribution of magnetized quark-nugget dark matter and comparison with observations

Authors: J. Pace VanDevender (VanDevender Enterprises LLC), Ian Shoemaker (Virginia Tech), T. Sloan (Lancaster University, UK), Aaron P. VanDevender (Founders Fund), Benjamin A. Ulmen (Sandia National Laboratories)

Comments: 24 pages including 2 page supplement, 6 figures, 1 table, 51 references. Submitted to Scientific Review on April 20, 2020

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

[118]  arXiv:2004.12829 (replaced) [pdf, other]

Title: WISEA J083011.95+283716.0: A Missing Link Planetary-Mass Object

Authors: Daniella C. Bardalez Gagliuffi, Jacqueline K. Faherty, Adam C. Schneider, Aaron Meisner, Dan Caselden, Guilluame Colin, Sam Goodman, J. Davy Kirkpatrick, Marc J. Kuchner, Jonathan Gagné, Sarah E. Logsdon, Adam J. Burgasser, Katelyn Allers, John Debes, John Wisniewski, Austin Rothermich, Nikolaj S. Andersen, Melina Thévenot, Jim Walla

Comments: 13 pages, 6 figures, 5 tables

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

[119]  arXiv:2004.12874 (replaced) [pdf, ps, other]

Title: Extremal Kerr white holes as a source of ultra high energy particles

Authors: Mandar Patil, Tomohiro Harada

Comments: 20 pages, 4 figures

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

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