Astrophysics
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New submissions for Fri, 10 Jan 20
- [1] arXiv:2001.02675 [pdf, other]
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Title: Radio jets: properties, life and impactAuthors: Raffaella Morganti (ASTRON and Kapteyn Astronomical Institute)Comments: 14 pages, 7 figures, Invited review IAU Symp 356 "Nuclear Activity in Galaxies Across Cosmic Time", ed. M. Povic et alSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
Our view of the properties of extragalactic radio jets and the impact they have on the host galaxy has expanded in the recent years. This has been possible thanks to the data from new or upgraded radio telescopes. This review briefly summarises the current status of the field and describes some of the exciting recent results and the surprises they have brought. In particular, the physical properties of radio jets as function of their radio power will be discussed together with the advance made in understanding the life-cycle of radio sources. The evolutionary stage (e.g. newly born, dying, restarted) of the radio AGN can be derived from their morphology and properties of the radio spectra. The possibilities offered by the new generation of low-frequency radio telescopes make it possible to derive (at least to first order) the time-scale spent in each phase. The presence of a cycle of activity ensures a recurrent impact of the radio jets on their surrounding inter-stellar and inter-galactic medium and, therefore, their relevance for AGN feedback. The last part is dedicated to the recent results showing the effect of jets on the surrounding galactic medium. The predictions made by numerical simulations on the impact of a radio jet (and in particular a newly born jet) on a clumpy medium describe well what is seen by the observations. The high resolution studies of jet-driven outflows of cold gas (HI and molecular) has provided new important addition both in term of quantifying the impact of the outflows and their relevance for feedback as well as for providing an unexpected view of the physical conditions of the gas under these extreme conditions.
- [2] arXiv:2001.02678 [pdf, other]
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Title: A Turbulent-Entropic Instability and the Fragmentation of Star-Forming CloudsComments: To be published in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
The kinetic energy of supersonic turbulence within interstellar clouds is subject to cooling by dissipation in shocks and subsequent line radiation. The clouds are therefore susceptible to a condensation process controlled by the specific entropy. In a form analogous to the thermodynamic entropy, the entropy for supersonic turbulence is proportional to the log of the product of the mean turbulent velocity and the size scale. We derive a dispersion relation for the growth of entropic instabilities in a spherical self-gravitating cloud and find that there is a critical maximum dissipation time scale, about equal to the crossing time, that allows for fragmentation and subsequent star formation. However, the time scale for the loss of turbulent energy may be shorter or longer, for example with rapid thermal cooling or the injection of mechanical energy. Differences in the time scale for energy loss in different star-forming regions may result in differences in the outcome, for example, in the initial mass function.
- [3] arXiv:2001.02680 [pdf, other]
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Title: A correlation between the number of satellites and the baryonic bulge-to-total ratio extending beyond the Local GroupComments: 5 pages, 1 figure, accepted for publication by MNRAS LettersSubjects: Astrophysics of Galaxies (astro-ph.GA)
Recent observations of the fields surrounding a few Milky-Way-like galaxies in the local Universe have become deep enough to enable investigations of the predictions of the standard LCDM cosmological model down to small scales outside the Local Group. Motivated by an observed correlation between the number of dwarf satellites (N_sat) and the bulge-to-total baryonic mass ratios (B/T) of the three main galaxies in the Local Group, i.e. the Milky Way, Andromeda, and Triangulum (M33), we use published data of three well-studied galaxies outside the Local Group, namely M81, Centaurus A, and M101, and their confirmed satellites, and we find a strong and significant correlation between N_sat and B/T. This presents itself in contradiction with the hitherto published results from cosmological simulations reporting an absence of a correlation between N_sat and B/T in the LCDM model. We conclude that, based on the current data, the N_sat vs. B/T correlation is no longer a property confined to only the Local Group.
- [4] arXiv:2001.02681 [pdf, other]
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Title: Detecting Interstellar Objects Through Stellar OccultationsComments: 5 pages, 4 figures, 1 table; submitted to ApJLSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Stellar occultations have been used to search for Kuiper Belt and Oort Cloud objects. We propose a search for interstellar objects based on the characteristic durations ($\sim 0.1 \mathrm{s}$) of their stellar occultation signals and high inclination relative to the ecliptic plane. An all-sky monitoring program of $\sim 2 \times 10^7$ stars with an R-band magnitude of 14 using 1-m telescopes with $0.1 \; \mathrm{s}$ cadences, is predicted to discover $\gtrsim 5$ interstellar objects per year.
- [5] arXiv:2001.02684 [pdf, other]
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Title: An empirical metallicity tracer in CEMP and C-normal starsComments: 12 pages, 15 figures, 7 pages appendix. Accepted by A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Deriving the metallicity, [Fe/H], in low-resolution spectra of carbon-enhanced metal-poor (CEMP) stars is a tedious task that, owing to the large number of line blends, often leads to uncertainties on [Fe/H] exceeding 0.25dex. The CEMP stars increase in number with decreasing [Fe/H] and some of these are known to be bona fide second generation halo stars. Hence, knowing their [Fe/H] is important for tracing the formation and chemical evolution of the Galaxy. Here, we aim to improve the [Fe/H] measurements in low-resolution spectra by avoiding issues related to blends. We improve our chemical tagging in such spectra at low metallicities. We developed an empirical way of deriving [Fe/H] in CEMP (and C-normal) stars that relates the equivalent width (EW) of strong lines, which remain detectable in lower-resolution, metal-poor spectra. The best [Fe/H] tracers are found to be Cr I and Ni I, which both show strong transitions in spectral regions that are free of molecular bands (between ~5200-6800A, a region accessible to most surveys). We derive different relations for dwarfs and giants. The relations are valid in the ranges ~-3<[Fe/H]<-0.5 and 10<EW<800mA (Cr) or [Fe/H]>-3.2 and EW>5mA (Ni), depending on the element and line as well as the stellar evolutionary stage. The empirical relations are valid for both CEMP and C-normal stars and have been proven to be accurate tracers in a sample of ~400 stars (mainly giants). The metallicities are accurate to within ~0.2 depending on the sample and resolution, and the empirical relations are robust to within 0.05-0.1dex. Our relations will improve the metallicity determination in future surveys, which will encounter a large number of CEMP stars, and will greatly speed up the process of determining [Fe/H] as the EWs only need to be measured in two or three lines in relatively clean regions compared to dealing with numerous blended Fe lines. Abrigded.
- [6] arXiv:2001.02687 [pdf, other]
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Title: EMERGE: Empirical predictions of galaxy merger rates since $z\sim6$Comments: Submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We explore the galaxy-galaxy merger rate with the empirical model for galaxy formation, EMERGE. On average, we find that between $2$ per cent and $6$ per cent of massive galaxies ($\log_{10}(m_{*}/M_{\odot}) \geq 10.3$) will experience a major merger per Gyr. Our model predicts galaxy merger rates that do not scale as a power-law with redshift, and exhibit a clear stellar mass and mass-ratio dependence, unlike the underlying halo-halo merger rate. Specifically, major mergers are more frequent at high masses and at low redshift. We show mergers are significant for the stellar mass growth of galaxies $\log_{10}(m_{*}/M_{\odot}) \gtrsim 11.0$. For the most massive galaxies major mergers dominate the accreted mass fraction, contributing as much as $90$ per cent of the total accreted stellar mass. We argue that these phenomena are a direct result of the stellar-to-halo mass relation, which results in massive galaxies having a higher likelihood of experiencing major mergers than low mass galaxies. Furthermore, we find no statistical evidence for mergers as a driving mechanism for quenching, with more than $58$ per cent of the most massive galaxies experiencing no major merger within $2$ Gyr of quenching. Our model produces a galaxy pair fraction consistent with resent observations, exhibiting a form best described by a power-law exponential function. Translating these pair fractions into merger rates results in an over prediction compared to the model intrinsic values. We find the pair fraction can be best mapped to the intrinsic merger rate by adopting a constant observation timescale $T_{obs}=2.56$ Gyr, assuming all observed pairs merge by $z=0$.
- [7] arXiv:2001.02688 [pdf, other]
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Title: Wandering Massive Black Holes or Analogs of the First Repeating Fast Radio Burst?Comments: 10 pages, 6 figures; submitted to ApJLSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The discovery of a persistent radio source coincident with the first repeating fast radio burst, FRB 121102, and offset from the center of its dwarf host galaxy has been used as evidence for a link with young millisecond magnetars born in superluminous supernovae (SLSNe) or long-duration gamma-ray bursts (LGRBs). A prediction of this scenario is that compact radio sources offset from the centers of dwarf galaxies may serve as signposts for at least some FRBs. Recently, Reines et al. 2019 presented the discovery of 20 such radio sources in nearby ($z\lesssim 0.055$) dwarf galaxies, and argued that these cannot be explained by emission from HII regions, normal supernova remnants, or normal radio supernovae. Instead, they attribute the emission to accreting wandering massive black holes. Here, we explore the alternative possibility that these sources are analogs of FRB 121102. We compare their properties --- radio luminosities, spectral energy distributions, light curves, ratios of radio-to-optical flux, and spatial offsets --- to FRB 121102, a few other well-localized FRBs, and potentially related systems, and find that these are all consistent as arising from the same population. We further compare their properties to the magnetar nebula model used to explain FRB 121102, as well as to theoretical off-axis LGRB light curves, and find overall consistency. Finally, we find a consistent occurrence rate relative to repeating FRBs and LGRBs. We outline key follow-up observations to further test these possible connections.
- [8] arXiv:2001.02689 [pdf, other]
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Title: A physically motivated definition for the size of galaxies in an era of ultra-deep imagingComments: 19 pages, 10 figures, MNRAS resubmitted after addressing referee comments. Key results of the paper are shown in Figures 2, 3 and 4. Chamba et al. (2020) applies this new size definition to ultra-diffuse galaxies showing that they have sizes of dwarf galaxies. Comments are welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Present-day multi-wavelength deep imaging surveys allow to characterise the outskirts of galaxies with unprecedented precision. Taking advantage of this situation, we define a new physically motivated measurement of size for galaxies based on the expected location of the gas density threshold for star formation. Employing both theoretical and observational arguments, we use the stellar mass density contour at 1 $M_{\rm \odot}$ pc$^{-2}$ as a proxy for this density threshold for star formation. This choice makes our size definition operative. With this new size measure, the intrinsic scatter of the global stellar mass ($M_{\rm \star}$) - size relation (explored over five orders of magnitude in stellar mass) decreases to $\sim$0.06 dex. This value is 2.5 times smaller than the scatter measured using the effective radius ($\sim$0.15 dex) and between 1.5 and 1.8 times smaller than those using other traditional size indicators such as $R_{\rm 23.5,i}$ ($\sim$0.09 dex), the Holmberg radius $R_{\rm H}$ ($\sim$0.09 dex) and the half-mass radius $R_{\rm e,M_{\star}}$ ($\sim$0.11 dex). Moreover, galaxies with 10$^7$ $M_{\rm \odot} <$ $M_{\star} < 10^{11}$ $M_{\rm \odot}$ increase monotonically in size following a power-law with a slope very close to 1/3, equivalent to an average stellar mass 3D density of $\sim$4.5$\times$10$^{-3}$ $M_{\rm \odot}$ pc$^{-3}$ for galaxies within this mass range. Galaxies with $M_{\rm \star}$$>$10$^{11}$ $M_{\rm \odot}$ show a different slope with stellar mass, which is suggestive of a larger gas density threshold for star formation at the epoch when their star formation peaks.
- [9] arXiv:2001.02691 [pdf, other]
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Title: Are ultra-diffuse galaxies Milky Way-sized?Comments: 9 pages, 7 figures, published in A&A Letters. Key result of the paper is shown in Figure 5. For a discussion on the physically motivated size definition used, see Trujillo et al. (2020)Journal-ref: A&A 633, L3 (2020)Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Now almost 70 years since its introduction, the effective or half-light radius has become a very popular choice for characterising galaxy size. However, the effective radius measures the concentration of light within galaxies and thus does not capture the intuitive definition of size which is related to the edge or boundary of objects. For this reason, we aim to demonstrate the undesirable consequence of using the effective radius to draw conclusions about the nature of faint 'ultra-diffuse galaxies' (UDGs) when compared to dwarfs and Milky Way-like galaxies. Instead of the effective radius, we use a measure of galaxy size based on the location of the gas density threshold required for star formation. Compared to the effective radius, this physically motivated definition places the sizes much closer to the boundary of a galaxy. Therefore, considering the sizes and stellar mass density profiles of UDGs and regular dwarfs, we find that the UDGs have sizes that are within the size range of dwarfs. We also show that currently known UDGs do not have sizes comparable to Milky Way-like objects. We find that, on average, UDGs are ten times smaller in extension than Milky Way-like galaxies. These results show that the use of size estimators sensitive to the concentration of light can lead to misleading results.
- [10] arXiv:2001.02692 [pdf, other]
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Title: Channels for streaming instability in dusty discsComments: Accepted for publication in MNRAS. 8 pages, 4 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Streaming instability is a privileged channel to bridge the gap between collisional growth of dust grains and planetesimal formation triggered by gravity. This instability is thought to develop through its secular mode, which is long-time growing and may not develop easily in real discs. We address this point by revisiting its perturbation analysis. A third-order expansion with respect to the Stokes number reveals important features over-looked so far. The secular mode can be stable. Epicycles can be unstable, more resistant to viscosity and are identified by Green's function analysis as promising channels for planetesimals formation.
- [11] arXiv:2001.02693 [pdf, other]
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Title: Reconstructing the observed ionizing photon production efficiency at z~2 using stellar population modelsAuthors: Themiya Nanayakkara, Jarle Brinchmann, Karl Glazebrook, Rychard Bouwens, Lisa Kewley, Kim-Vy Tran, Michael Cowley, Deanne Fisher, Glenn G. Kacprzak, Ivo Labbe, Caroline StraatmanComments: Accepted for publication in the ApJ, 8 figures, 15 pagesSubjects: Astrophysics of Galaxies (astro-ph.GA)
The ionizing photon production efficiency, $\xi_{ion}$, is a critical parameter that provides a number of physical constraints to the nature of the early Universe, including the contribution of galaxies to the timely completion of the reionization of the Universe. Here we use KECK/MOSFIRE and ZFOURGE multi-band photometric data to explore the $\xi_{ion}$ of a population of galaxies at $z\sim2$ with $log_{10}(M_*/M_\odot)\sim9.0-11.5$. Our 130 \Halpha\ detections show a median $log_{10}(\xi_{ion}[Hz/erg])$ of $24.8\pm0.5$ when dust corrected using a Calzetti et al. (2000) dust prescription. Our values are typical of mass/magnitude selected $\xi_{ion}$ values observed in the $z\sim2$ Universe. Using BPASSv2.2.1 and Starburst99 stellar population models with simple parametric star-formation-histories (SFH), we find that even with models that account for effects of stellar evolution with binaries/stellar rotation, model galaxies at $log_{10}(\xi_{ion}[Hz/erg])\lesssim25.0$ have low H$\alpha$ equivalent widths (EW) and redder colors compared to our $z\sim2$ observed sample. We find that introducing star-bursts to the SFHs resolve the tension with the models, however, due to the rapid time evolution of $\xi_{ion}$, H$\alpha$ EWs, and rest-frame optical colors, our Monte Carlo simulations of star-bursts show that random distribution of star-bursts in evolutionary time of galaxies are unlikely to explain the observed distribution. Thus, either our observed sample is specially selected based on their past SFH or stellar models require additional mechanisms to reproduce the observed high UV luminosity of galaxies for a given production rate of hydrogen ionizing photons.
- [12] arXiv:2001.02695 [pdf, other]
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Title: Stellar Kinematics and Environment at z~0.8 in the LEGA-C Survey: Massive, Slow-Rotators are Built First in Overdense EnvironmentsAuthors: Justin Cole, Rachel Bezanson, Arjen van der Wel, Eric Bell, Francesco D'Eugenio, Marijn Franx, Anna Gallazzi, Josha van Houdt, Adam Muzzin, Camilla Pacifici, Jesse van de Sande, David Sobral, Caroline Straatman, Po-Feng WuComments: 10 pages, 5 figures, submitted to ApJ LettersSubjects: Astrophysics of Galaxies (astro-ph.GA)
In this letter, we investigate the impact of environment on integrated and spatially-resolved stellar kinematics of a sample of massive, quiescent galaxies at intermediate redshift ($0.6<z<1.0$). For this analysis, we combine photometric and spectroscopic parameters from the UltraVISTA and Large Early Galaxy Astrophysics Census (LEGA-C) surveys in the COSMOS field and environmental measurements. We analyze the trends with overdensity (1+$\delta$) on the rotational support of quiescent galaxies and find no universal trends at either fixed mass or fixed stellar velocity dispersion. This is consistent with previous studies of the local Universe; rotational support of massive galaxies depends primarily on stellar mass. We highlight two populations of massive galaxies ($\log M_\star/M_\odot\geq11$) that deviate from the average mass relation. First, the most massive galaxies in the most under-dense regions ($(1+\delta)\leq1$) exhibit elevated rotational support. Similarly, at the highest masses ($\log M_\star/M_\odot\geq11.25$) the range in rotational support is significant in all but the densest regions. This corresponds to an increasing slow-rotator fraction such that only galaxies in the densest environments ($(1+\delta)\geq3.5$) are primarily (90$\pm$10\%) slow-rotators.This effect is not seen at fixed velocity dispersion, suggesting minor merging as the driving mechanism: only in the densest regions have the most massive galaxies experienced significant minor merging, building stellar mass and diminishing rotation without significantly affecting the central stellar velocity dispersion. In the local Universe, most massive galaxies are slow-rotators, regardless of environment, suggesting minor merging occurs at later cosmic times $(z\lesssim0.6)$ in all but the most dense environments.
- [13] arXiv:2001.02696 [pdf, other]
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Title: The Bolometric Quasar Luminosity Function at z = 0-7Authors: Xuejian Shen, Philip F. Hopkins, Claude-André Faucher-Giguère, D. M. Alexander, Gordon T. Richards, Nicholas P. Ross, R. C. HickoxComments: Submitted to MNRAS. The code and data are available at this https URL Comments are welcomed!Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
In this paper, we provide updated constraints on the bolometric quasar luminosity function (QLF) from $z=0$ to $z=7$. The constraints are based on an observational compilation that includes observations in the rest-frame IR, B band, UV, soft and hard X-ray in past decades. Our method follows \citet{Hopkins2007} with an updated quasar SED model and bolometric and extinction corrections. The new best-fit bolometric quasar luminosity function behaves qualitatively different from the \citet{Hopkins2007} model at high redshift. The bright-end slope is steeper at $z\gtrsim 2$ compared with the old model. The faint-end slope is steeper at $z\gtrsim 3$ and becomes progressively steeper at higher redshifts. The steep faint-end slope we constrain is primarily driven by observations in the rest-frame UV and could be affected by the lack of measurements of the faint-end QLF. Multi-band observations on the faint-end QLF are needed to confirm this trend. The evolutionary pattern of the bolometric QLF can be interpreted as an early phase likely dominated by the hierarchical assembly of structures and a late phase likely dominated by the quenching of galaxies. We explore the implications of this model on the ionizing photon production by quasars, the CXB spectrum, the SMBH mass density and mass functions. The predicted hydrogen ionization rate contributed by quasars is subdominant during the epoch of reionization and only becomes important at $z\lesssim 3$. The predicted CXB spectrum, cosmic SMBH mass density and SMBH mass function are generally consistent with existing observations.
- [14] arXiv:2001.02697 [pdf, other]
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Title: Self-consistent analysis of stellar clusters: An application to HST data of the halo globular cluster NGC 6752Authors: Stefano O. Souza, Leandro O. Kerber, Beatriz Barbuy, Angeles Pérez-Villegas, Raphael A. P. Oliveira, Domenico NardielloComments: 17 pages, 11 figures, 3 tables. Accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The Bayesian isochrone fitting using the Markov chain Monte Carlo algorithm is applied, to derive the probability distribution of the parameters age, metallicity, reddening, and absolute distance modulus. We introduce the \texttt{SIRIUS} code by means of simulated color-magnitude diagrams, including the analysis of multiple stellar populations. The population tagging is applied from the red giant branch to the bottom of the main sequence. Through sanity checks using synthetic {\it HST} color-magnitude diagrams of globular clusters we verify the code reliability in the context of simple and multiple stellar populations. In such tests, the formal uncertainties in age or age difference, metallicity, reddening, and absolute distance modulus can reach $400$ Myr, $0.03$ dex, $0.01$ mag, and $0.03$ mag, respectively. We apply the method to analyse NGC 6752, using Dartmouth stellar evolutionary models. Assuming a single stellar population, we derive an age of $13.7\pm0.5$ Gyr and a distance of $d_{\odot}=4.11\pm 0.08$ kpc, with the latter in agreement within $~3\sigma$ with the inverse Gaia parallax. In the analysis of the multiple stellar populations, three {populations} are clearly identified. From the Chromosome Map and UV/Optical two-color diagrams inspection, we found a fraction of stars of $25\pm5$, $46\pm7$, and $29\pm5$ per cent, for the first, second, and third generations, respectively. These fractions are in good agreement with the literature. An age difference of $500\pm410$ Myr between the first and the third generation is found, with the uncertainty decreasing to $400$ Myr when the helium enhancement is taken into account.
- [15] arXiv:2001.02700 [pdf, other]
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Title: Multiplicity of the red supergiant population in the young massive cluster NGC 330Authors: L. R. Patrick, D. J. Lennon, C. J. Evans, H. Sana, J. Bodensteiner, N. Britavskiy, R. Dorda, A. Herrero, I. Negueruela, A. de KoterComments: Accepted to A&A. 14 pagesSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
The multiplicity properties of massive stars are one of the important outstanding issues in stellar evolution. Quantifying the binary statistics of all evolutionary phases is essential to paint a complete picture of how and when massive stars interact with their companions, and to determine the consequences of these interactions. We investigate the multiplicity of an almost complete census of red supergiant stars (RSGs) in NGC 330, a young massive cluster in the SMC. Using a combination of multi-epoch HARPS and MUSE spectroscopy, we estimate radial velocities and assess the kinematic and multiplicity properties of 15 RSGs in NGC 330. Radial velocities are estimated to better than +/-100 m/s for the HARPS data. The line-of-sight velocity dispersion for the cluster is estimated as 3.20 +0.69-0.52 km/s. When virial equilibrium is assumed, the dynamical mass of the cluster is log (M{dyn} /M{sun}) = 5.20+/-0.17, in good agreement with previous upper limits. We detect significant radial velocity variability in our multi-epoch observations and distinguish between variations caused by atmospheric activity and those caused by binarity. The binary fraction of NGC 330 RSGs is estimated by comparisons with simulated observations of systems with a range of input binary fractions. In this way, we account for observational biases and estimate the intrinsic binary fraction for RSGs in NGC 330 as f{RSG} = 0.3+/-0.1 for orbital periods in the range 2.3< log P [days] <4.3, with q>0.1. Using the distribution of the luminosities of the RSG population, we estimate the age of NGC 330 to be 45+/-5 Myr and estimate a red straggler fraction of 50%. We estimate the binary fraction of RSGs in NGC 330 and conclude that it appears to be lower than that of main-sequence massive stars, which is expected because interactions between an RSG and a companion are assumed to effectively strip the RSG envelope.
- [16] arXiv:2001.02701 [pdf, other]
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Title: X-ray and gamma-ray orbital variability from the gamma-ray binary HESS J1832-093Comments: 9 pages, 9 figures. Submitted to A&ASubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Context. Gamma-ray binaries are systems composed of a massive star and a compact object whose interaction leads to particle acceleration up to relativistic energies. In the last fifteen years, a few binaries have been discovered to emit at high energies, but their number is still scarce. The TeV source HESS J1832-093 has been proposed as a binary candidate, although its nature is unclear. Neither a GeV counterpart nor a period was found for it. Aims. The purpose of this work is to search for a gamma-ray source at GeV energies to understand the origin of the TeV signal. For an unambiguous identification of its binary nature, finding an orbital modulation is crucial. Methods. We have analysed data spanning more than 10 years from the Fermi Large Area Telescope (Fermi-LAT), together with Swift archival observations taken between 2015 and 2018, using both the X-Ray Telescope (XRT) and UltraViolet and Optical Telescope (UVOT). We searched for periodicities in both X-ray and gamma-ray bands using a Lomb-Scargle periodogram. Results. We find a periodic modulation of \sim 86 days in the X-ray source XMMU J183245-0921539, together with indications of gamma-ray modulation with a compatible period in 4FGL J1832.9-0913. Neither an optical nor an UV counterpart is found at the X-ray source location. The overall spectral energy distribution strongly resembles the known gamma-ray binary HESS J0632+057. Conclusions. Both the spectrum and the discovery of an orbital period allow the identification of the TeV source HESS J1832-093 as a new member of the gamma-ray binary class.
- [17] arXiv:2001.02708 [pdf, other]
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Title: Hints of gamma-ray orbital variability from gamma^2 VelorumComments: 7 pages, 6 figures. Submitted to A&ASubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Context. Colliding wind binaries are massive systems featuring strong, interacting stellar winds which may act as particle accelerators. Therefore, such binaries are good candidates for detection at high energies. However, only the massive binary Eta Carinae has been firmly associated with a gamma-ray signal. A second system, gamma^2 Velorum, is positionally coincident with a gamma-ray source, but unambiguous identification remains lacking. Aims. Observing orbital modulation of the flux would establish an unambiguous identification of the binary gamma^2 Velorum as the gamma-ray source detected by the Fermi Large Area Telescope (Fermi-LAT). Methods. We have used more than 10 years of observations with Fermi-LAT. Events are folded with the orbital period of the binary to search for variability. Systematic errors that might arise from the strong emission of the nearby Vela pulsar are studied by comparing with a more conservative pulse-gated analysis. Results. Hints of orbital variability are found, indicating maximum flux from the binary during apastron passage. Conclusions. Our analysis strengthens the possibility that gamma-rays are produced in gamma^2 Velorum, most likely as a result of particle acceleration in the wind collision region. The observed orbital variability is consistent with predictions from recent MHD simulations, but contrasts with the orbital variability from Eta Carinae, where the peak of the light curve is found at periastron.
- [18] arXiv:2001.02717 [pdf, other]
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Title: Frequency chirped continuous-wave sodium laser guide starsAuthors: F. Pedreros Bustos, R. Holzlöhner, S. Rochester, D. Bonaccini Calia, J. Hellemeier, D. BudkerSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
We numerically study a method to increase the photon return flux of continuous-wave laser guide stars using one-dimensional atomic cooling principles. The method relies on chirping the laser towards higher frequencies following the change in velocity of sodium atoms due to recoil, which raises atomic populations available for laser excitation within the Doppler distribution. The efficiency of this effect grows with the average number of atomic excitations between two atomic collisions in the mesosphere. We find the parameters for maximizing the return flux and evaluate the performance of chirping for operation at La Palma. According to our simulations, the optimal chirp rate lies between 0.8-1.0 MHz/$\mu$s and an increase in the fluorescence of the sodium guide star up to 60% can be achieved with current 20 W-class guide star lasers.
- [19] arXiv:2001.02720 [pdf, other]
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Title: Signatures of first galaxies at FIR/sub-mm wavelengthsComments: 3 pages, 2 figures. Accepted for publication in BAAA, Vol. 61B, 2020Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We explore the possibility of detecting first galaxies with a generic far-infrared/sub-millimeter telescope by applying an analytical model of primordial dust emission. As shown in previous works, galaxies at redshifts $z>7$ experience a strong negative K-correction in such a way that systems of similar masses are brighter at higher $z$. In addition, at a given mass and $z$, our model predicts that luminosity fluxes increase proportionally to the dust-to-metal ratios ($D/M$) of primeval sources. We evaluate the observability of model sources at different $z>7$ as a function of the observed survey area ($\Delta \Omega$) and sensitivity ($S$) of a generic instrument. Assuming $\Delta \Omega \sim 10~{\rm deg}^2$ and a plausible $S \sim 1~{\mu}{\rm Jy}$ for a near future survey, we could assure the detection of at least one typical source with $D/M \sim 5\times10^{-3}$ at $z>7$. For $S\gtrsim 1~{\mu}{\rm Jy}$ and $\Delta \Omega \lesssim 10~{\rm deg}^2$, higher than typical $D/M$ are required to detect at least one individual source at $z>7$. The observability of model galaxies is also affected by the size distribution of dust grains, specially towards higher $z$.
- [20] arXiv:2001.02722 [pdf, ps, other]
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Title: Searching for optical companions to four binary millisecond pulsars with the Gran Telescopio CanariasAuthors: A. Yu. Kirichenko, A. V. Karpova, D. A. Zyuzin, S. V. Zharikov, E. A. Lopez, Yu. A. Shibanov, P. C. C. Freire, E. Fonseca, A. Cabrera-LaversComments: Accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
We report on multi-band photometric observations of four binary millisecond pulsars with the Gran Telescopio Canarias. The observations led to detection of binary companions to PSRs J1630+3734, J1741+1351 and J2042+0246 in the Sloan g', r' and i' bands. Their magnitudes in the r' band are $\approx$24.4, 24.4 and 24.0, respectively. We also set a 3$\sigma$ upper limit on the brightness of the PSR J0557+1550 companion in the r' band of $\approx$25.6 mag. Combining the optical data with the radio timing measurements and white dwarf cooling models, we show that the detected companions are cool low-mass white dwarfs with temperatures and ages in the respective ranges of (4-7)$\times 10^3$ K and 2-5 Gyr. All the detected white dwarfs are found to likely have either pure hydrogen or mixed helium-hydrogen atmospheres.
- [21] arXiv:2001.02723 [pdf, other]
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Title: Optical polarization properties of AGN with significant VLBI-Gaia offsetsAuthors: Y.Y. Kovalev (ASC Lebedev, MIPT, MPIfR), D. I. Zobnina (ASC Lebedev), A. V. Plavin (ASC Lebedev, MIPT), D. Blinov (IoA Crete, U Crete, SPbU)Comments: 6 pages, 4 figures, 2 tables; accepted by MNRAS Letters; table 2 is electronic only - available from the preprint sourceSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
Significant positional offsets of the value from 1 mas to more than 10 mas were found previously between radio (VLBI) and optical (Gaia) positions of active galactic nuclei (AGN). They happen preferentially parallel to the parsec-scale jet direction. AGN with VLBI-to-Gaia offsets pointed downstream the jet are found to have favourably higher optical polarization, as expected if extended optical jets dominate in the emission and shift the Gaia centroid away from the physical nucleus of the source. Upstream offsets with the suggested domination of accretion disks manifest themselves through the observed low optical polarization. Direction of linear optical polarization is confirmed to preferentially align with parsec-scale jets in AGN with dominant jets consistent with a toroidal magnetic field structure. Our findings support the disk-jet interpretation of the observed positional offsets. These results call on an intensification of AGN optical polarization monitoring programs in order to collect precious observational data. Taken together with the continued VLBI and Gaia observations, they will allow researchers to reconstruct detailed models of the disk-jet system in AGN on parsec scales.
- [22] arXiv:2001.02725 [pdf, ps, other]
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Title: A new and unusual LBV-like outburst from a Wolf-Rayet star in the outskirts of M33Authors: Nathan Smith, Jennifer E. Andrews, Maxwell Moe, Peter Milne, Christopher Bilinski, Charles D. Kilpatrick, Wen-Fai Fong, Carles Badenes, Alexei V. Filippenko, Mansi Kasliwal, Jeffrey M. SilvermanComments: accepted in MNRAS. 20 pages, 15 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
MCA-1B (also called UIT003) is a luminous hot star in the western outskirts of M33, classified over 20yr ago with a spectral type of Ofpe/WN9 and identified then as a candidate luminous blue variable (LBV). Palomar Transient Factory data reveal that this star brightened in 2010, with a light curve resembling that of the classic LBV star AFAnd in M31. Other Ofpe/WN9 stars have erupted as LBVs, but MCA-1B was unusual because it remained hot. It showed a WN-type spectrum throughout its eruption, whereas LBVs usually get much cooler. MCA-1B showed an almost four-fold increase in bolometric luminosity and a doubling of its radius, but its temperature stayed around 29kK. As it faded, it shifted to even hotter temperatures, exhibiting a WN7/WN8-type spectrum, and doubling its wind speed. MCA-1B is reminiscent of some supernova impostors, and its location resembles the isolated environment of SN 2009ip. It is most similar to HD5980 (in the SMC) and GR 290 (also in M33). Whereas these two LBVs exhibited B-type spectra in eruption, MCA-1B is the first clear case where a Wolf-Rayet (WR) spectrum persisted at all times. Together, MCA-1B, HD 5980, and GR 290 constitute a class of WN-type LBVs, distinct from S Doradus LBVs. They are most interesting in the context of LBVs at low metallicity, a possible post-LBV/WR transition in binaries, and as likely Type~Ibn supernova progenitors.
- [23] arXiv:2001.02732 [pdf, other]
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Title: Exploring the acceleration mechanisms for particle injection and power-law formation during trans-relativistic magnetic reconnectionComments: Submitted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)
Magnetic reconnection in the relativistic and trans-relativistic regimes is able to accelerate particles to hard power law energy spectra $f \propto \gamma^{-p}$ (approaching $p=1$). The underlying acceleration mechanism that determines the spectral shape is currently a topic of intense investigation. By means of fully kinetic plasma simulations, we carry out a study of particle acceleration during magnetic reconnection in the trans-relativistic regime of a proton-electron plasma. While earlier work in this parameter regime has focused on the effects of electric field parallel to the local magnetic field on the particle injection (from thermal energy to the lower energy bound of the power-law spectrum), here we examine the roles of both parallel and perpendicular electric fields to gain a more complete understanding on the injection process and further development of a power-law spectrum. We show that the parallel electric field does contribute significantly to particle injection, and is more important in the initial phase of magnetic reconnection. However, as the simulation proceeds, the acceleration by the perpendicular electric field becomes more important for particle injection and completely dominates the acceleration responsible for the high-energy power-law spectrum. This holds robustly, in particular for longer reconnection times and larger systems, i.e. in simulations that are more indicative of the processes in astrophysical sources.
- [24] arXiv:2001.02780 [pdf, other]
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Title: Large Scale Structure Reconstruction with Short-Wavelength ModesComments: 4 pages, 3 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Large scale density modes are difficult to measure because they are sensitive to systematic observational errors in galaxy surveys but we can study them indirectly by observing their impact on small scale perturbations. Cosmological perturbation theory predicts that second-order density inhomogeneities are a convolution of a short- and a long-wavelength mode. This arises physically because small scale structures grow at different rates depending on the large scale environment in which they reside. This induces an off-diagonal term in the two-point statistics in Fourier space that we use as the basis for a quadratic estimator for the large scale field. We demonstrate that this quadratic estimator works well on an N-body simulation of size (2.5 h^{-1} Gpc)^3. In particular, the quadratic estimator successfully reconstructs the long-wavelength modes using only small-scale information. This opens up novel opportunities to study structure on the largest observable scales.
- [25] arXiv:2001.02791 [pdf, other]
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Title: The 3.4 μm absorption of the Titan's stratosphere: contribution of ethane, propane, butane and complex hydrogenated organicsJournal-ref: Icarus 339 (2020)Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
The complex organic chemistry harbored by the atmosphere of Titan has been investigated in depth by Cassini observations. Among them, a series of solar occultations performed by the VIMS instrument throughout the 13 years of Cassini revealed a strong absorption centered at 3.4 $\mu$m. Several molecules present in Titan's atmosphere create spectral features in that wavelength region, but their individual contributions are difficult to disentangle. In this work, we quantify the contribution of the various molecular species to the 3.4 $\mu$m band using a radiative transfer model. Ethane and propane are a significant component of the band but they are not enough to fit the shape perfectly, then we need something else. Polycyclic Aromatic Hydrocarbons (PAHs) and more complex polyaromatic hydrocarbons like Hydrogenated Amorphous Carbons (HACs) are the most plausible candidates because they are rich in C-H bonds. PAHs signature have already been detected above ~900 km, and they are recognized as aerosols particles precursors. High similarities between individual spectra impede abundances determinations.
- [26] arXiv:2001.02800 [pdf, other]
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Title: Complex Variability of Kepler AGN Revealed by Recurrence AnalysisComments: 22 pages, 8 figures, and 1 table; submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
The advent of new time domain surveys and the imminent increase in astronomical data expose the shortcomings in traditional time series analysis (such as power spectra analysis) in characterising the abundantly varied, complex and stochastic light curves of Active Galactic Nuclei (AGN). Recent applications of novel methods from non-linear dynamics have shown promise in characterising higher modes of variability and time-scales in AGN. Recurrence analysis in particular can provide complementary information about characteristic time-scales revealed by other methods, as well as probe the nature of the underlying physics in these objects. Recurrence analysis was developed to study the recurrences of dynamical trajectories in phase space, which can be constructed from one-dimensional time series such as light curves. We apply the methods of recurrence analysis to two optical light curves of Kepler-monitored AGN. We confirm the detection and period of an optical quasi-periodic oscillation in one AGN, and confirm multiple other time-scales recovered from other methods ranging from 5 days to 60 days in both objects. We detect regions in the light curves that deviate from regularity, provide evidence of determinism and non-linearity in the mechanisms underlying one light curve (KIC 9650712), and determine a linear stochastic process recovers the dominant variability in the other light curve (Zwicky 229--015). We discuss possible underlying processes driving the dynamics of the light curves and their diverse classes of variability.
- [27] arXiv:2001.02808 [pdf, other]
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Title: A Comparison of Flare Forecasting Methods. IV. Evaluating Consecutive-Day Forecasting PatternsAuthors: Sung-Hong Park, K. D. Leka, Kanya Kusano, Jesse Andries, Graham Barnes, Suzy Bingham, D. Shaun Bloomfield, Aoife E. McCloskey, Veronique Delouille, David Falconer, Peter T. Gallagher, Manolis K. Georgoulis, Yuki Kubo, Kangjin Lee, Sangwoo Lee, Vasily Lobzin, JunChul Mun, Sophie A. Murray, Tarek A. M. Hamad Nageem, Rami Qahwaji, Michael Sharpe, Rob A. Steenburgh, Graham Steward, Michael TerkildsenComments: 33 pages, 13 figures, accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
A crucial challenge to successful flare prediction is forecasting periods that transition between "flare-quiet" and "flare-active". Building on earlier studies in this series (Barnes et al. 2016; Leka et al. 2019a,b) in which we describe methodology, details, and results of flare forecasting comparison efforts, we focus here on patterns of forecast outcomes (success and failure) over multi-day periods. A novel analysis is developed to evaluate forecasting success in the context of catching the first event of flare-active periods, and conversely, of correctly predicting declining flare activity. We demonstrate these evaluation methods graphically and quantitatively as they provide both quick comparative evaluations and options for detailed analysis. For the testing interval 2016-2017, we determine the relative frequency distribution of two-day dichotomous forecast outcomes for three different event histories (i.e., event/event, no-event/event and event/no-event), and use it to highlight performance differences between forecasting methods. A trend is identified across all forecasting methods that a high/low forecast probability on day-1 remains high/low on day-2 even though flaring activity is transitioning. For M-class and larger flares, we find that explicitly including persistence or prior flare history in computing forecasts helps to improve overall forecast performance. It is also found that using magnetic/modern data leads to improvement in catching the first-event/first-no-event transitions. Finally, 15% of major (i.e., M-class or above) flare days over the testing interval were effectively missed due to a lack of observations from instruments away from the Earth-Sun line.
- [28] arXiv:2001.02809 [pdf]
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Title: Evolving parsec-scale radio structure in the most distant blazar knownAuthors: Tao An, Prashanth Mohan, Yingkang Zhang, Sándor Frey, Jun Yang, Krisztina É. Gabányi, Leonid I. Gurvits, Zsolt Paragi, Krisztina Perger, Zhenya ZhengComments: 3 figures, 2 supplementary figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Blazars are a sub-class of quasars with Doppler boosted jets oriented close to the line of sight, and thus efficient probes of supermassive black hole growth and their environment, especially at high redshifts. Here we report on Very Long Baseline Interferometry observations of a blazar J0906+6930 at z = 5.47, which enabled the detection of polarised emission and measurement of jet proper motion at parsec scales. The observations suggest a less powerful jet compared with the general blazar population, including lower proper motion and bulk Lorentz factor. This coupled with a previously inferred high accretion rate indicate a transition from an accretion radiative power to a jet mechanical power based transfer of energy and momentum to the surrounding gas.While alternative scenarios could not be fully ruled out, our results indicate a possibly nascent jet embedded in and interacting with a dense medium resulting in a jet bending.
- [29] arXiv:2001.02812 [pdf, other]
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Title: ALMA uncovers the [CII] emission and warm dust continuum in a z = 8.31 Lyman break galaxyAuthors: Tom J. L. C. Bakx, Yoichi Tamura, Takuya Hashimoto, Akio K. Inoue, Minju M. Lee, Ken Mawatari, Kazuaki Ota, Hideki Umehata, Erik Zackrisson, Bunyo Hatsukade, Kotaro Kohno, Yuichi Matsuda, Hiroshi Matsuo, Takashi Okamoto, Takatoshi Shibuya, Ikkoh Shimizu, Yoshiaki Taniguchi, Naoki YoshidaComments: 15 pages, 8 figures, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We report on the detection of the [CII] 157.7 $\mu$m emission from the Lyman break galaxy (LBG) MACS0416_Y1 at z = 8.3113, by using the Atacama Large Millimeter/submillimeter Array (ALMA). The luminosity ratio of [OIII] 88 $\mu$m (from previous campaigns) to [CII] is 9.31 $\pm$ 2.6, indicative of hard interstellar radiation fields and/or a low covering fraction of photo-dissociation regions. The emission of [CII] is cospatial to the 850 $\mu$m dust emission (90 $\mu$m rest-frame, from previous campaigns), however the peak [CII] emission does not agree with the peak [OIII] emission, suggesting that the lines originate from different conditions in the interstellar medium. We fail to detect continuum emission at 1.5 mm (160 $\mu$m rest-frame) down to 18 $\mu$Jy (3$\sigma$). This nondetection places a strong limit on the dust spectrum, considering the 137 $\pm$ 26 $\mu$Jy continuum emission at 850 $\mu$m. This suggests an unusually warm dust component (T $>$ 80 K, 90% confidence limit), and/or a steep dust-emissivity index ($\beta_{\rm dust}$ $>$ 2), compared to galaxy-wide dust emission found at lower redshifts (typically T $\sim$ 30 - 50 K, $\beta_{\rm dust}$ $\sim$ 1 - 2). If such temperatures are common, this would reduce the required dust mass and relax the dust production problem at the highest redshifts. We therefore warn against the use of only single-wavelength information to derive physical properties, recommend a more thorough examination of dust temperatures in the early Universe, and stress the need for instrumentation that probes the peak of warm dust in the Epoch of Reionization.
- [30] arXiv:2001.02815 [pdf, other]
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Title: Estimating dust attenuation from galactic spectra. I. methodology and testsComments: 21 pages, 11 figures, Submitted to ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
We develop a method to estimate the dust attenuation curve of galaxies from full spectral fitting of their optical spectra. Motivated from previous studies, we separate the small-scale features from the large-scale spectral shape, by performing a moving average method to both the observed spectrum and the simple stellar population model spectra. The intrinsic dust-free model spectrum is then derived by fitting the observed ratio of the small-scale to large-scale (S/L) components with the S/L ratios of the SSP models. The selective dust attenuation curve is then determined by comparing the observed spectrum with the dust-free model spectrum. One important advantage of this method is that the estimated dust attenuation curve is independent of the shape of theoretical dust attenuation curves. We have done a series of tests on a set of mock spectra covering wide ranges of stellar age and metallicity. We show that our method is able to recover the input dust attenuation curve accurately, although the accuracy depends slightly on signal-to-noise ratio of the spectra. We have applied our method to a number of edge-on galaxies with obvious dust lanes from the ongoing MaNGA survey, deriving their dust attenuation curves and $E(B-V)$ maps, as well as dust-free images in $g$, $r$, and $i$ bands. These galaxies show obvious dust lane features in their original images, which largely disappear after we have corrected the effect of dust extinction. The vertical brightness profiles of these galaxies become axis-symmetric and can well be fitted by a simple model proposed for the disk vertical structure.
- [31] arXiv:2001.02837 [pdf, other]
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Title: The Intriguing Parsec-Scale Radio Structure in the "Offset AGN" KISSR 102Authors: P. Kharb (NCRA-TIFR), D. Lena (SRON), Z. Paragi (JIVE), S. Subramanian (IIA), S. Vaddi (NCRA-TIFR), M. Das (IIA), Rubinur K. (NCRA-TIFR)Comments: 11 pages, 6 figures, ApJ acceptedSubjects: Astrophysics of Galaxies (astro-ph.GA)
We report the detection of an intriguing parsec-scale radio source in the "offset AGN" candidate, KISSR 102. The elliptical host galaxy includes two optical nuclei at a projected separation of 1.54 kpc, N1 and N2, to the south-east and north-west, respectively. Phase-referenced VLBA observations at 1.5 and 4.9 GHz of this LINER galaxy, have detected double radio components (A and B) at a projected separation of 4.8 parsec at 1.5 GHz, and another partially-resolved double radio structure at 4.9 GHz coincident with the brighter radio component A. These radio detections are confined to the optical nucleus N1. The brightness temperatures of all the detected radio components are high, $\gtrsim10^8$ K, consistent with them being components of a radio AGN. The 1.5-4.9 GHz spectral index is inverted ($\alpha\sim+0.64\pm0.08$) for component A and steep for component B ($\alpha \lesssim-1.6$). The dramatic change in the spectral indices of A and B is inconsistent with it being a typical "core-jet" structure from a single AGN or the mini-lobes of a compact symmetric object. To be consistent with a "core-jet" structure, the jet in KISSR 102 would need to be undergoing strong jet-medium interaction with dense surrounding media resulting in a drastic spectral steepening of the jet. Alternatively, the results could be consistent with the presence of a parsec-scale binary radio AGN, which is the end result of a three-body interaction involving three supermassive black holes in the centre of KISSR 102.
- [32] arXiv:2001.02840 [pdf, other]
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Title: Kepler-1661 b: A Neptune-sized Kepler Transiting Circumbinary Planet around a Grazing Eclipsing BinaryAuthors: Quentin J Socia, William F Welsh, Jerome A Orosz, William D Cochran, Michael Endl, Billy Quarles, Donald R Short, Guillermo Torres, Gur Windmiller, Mitchell YenawineComments: 37 pages, 15 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
We report the discovery of a Neptune-size (R_p = 3.87 +/- 0.06 R_Earth) transiting circumbinary planet, Kepler-1661 b, found in the Kepler photometry. The planet has a period of ~175 days and its orbit precesses with a period of only 35 years. The precession causes the alignment of the orbital planes to vary, and the planet is in a transiting configuration only ~7% of the time as seen from Earth. As with several other Kepler circumbinary planets, Kepler-1661 b orbits close to the stability radius, and is near the (hot) edge of habitable zone. The planet orbits a single-lined, grazing eclipsing binary, containing a 0.84 M_Sun and 0.26 M_Sun pair of stars in a mildly eccentric (e=0.11), 28.2-day orbit. The system is fairly young, with an estimated age of ~1-3 Gyrs, and exhibits significant starspot modulations. The grazing-eclipse configuration means the system is very sensitive to changes in the binary inclination, which manifests itself as a change in the eclipse depth. The starspots contaminate the eclipse photometry, but not in the usual way of inducing spurious eclipse timing variations. Rather, the starspots alter the normalization of the light curve, and hence the eclipse depths. This can lead to spurious eclipse depth variations, which are then incorrectly ascribed to binary orbital precession.
- [33] arXiv:2001.02849 [pdf, other]
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Title: On the Impact of Random Residual Calibration Error on the Gibbs ILC Estimates over Large Angular ScalesComments: 8 pages, 4 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Residual error in calibration coefficients corresponding to observed CMB maps is an important issue while estimating a pure CMB signal. A component separation method, if these errors in the input foreground contaminated CMB maps are not properly taken into account, may lead to bias in the cleaned CMB map and estimated CMB angular power spectrum. But the inability to exactly determine the calibration coefficients corresponding to each observed CMB map from any CMB experiment makes it very difficult to incorporate their exact and actual values in a component separation analysis. Hence the effect of any random and residual calibration error on the cleaned CMB map and its angular power spectrum of a component separation problem can only be understood by performing detailed Monte Carlo simulations. In this paper, we investigate the impact of using input foreground contaminated CMB maps with random calibration errors on posterior density of cleaned CMB map and theoretical CMB angular power spectrum over large angular scales of the sky following the Gibbs ILC method proposed by \cite{Sudevan:2018qyj}. By performing detailed Monte Carlo simulations of WMAP and Planck temperature anisotropy observations with calibration errors compatible with them we show that the best-fit map corresponding to posterior maximum is minimally biased in Gibbs ILC method by a CMB normalization bias and residual foreground bias. The bias in best-fit CMB angular power spectrum with respect to the case where no calibration error is present are $\sim 28 \mu K^2$ and $-4.7 \mu K^2$ respectively between $2 \le \ell \le 15$ and $16 \le \ell \le 32$. The calibration error induced error in best-fit power spectrum causes an overall $6\%$ increase of the net error when added in quadrature with the cosmic variance induced error.
- [34] arXiv:2001.02875 [pdf, other]
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Title: A flat-spectrum flare in S4 0444+63 revealed by a new implementation of multi-wavelength single-dish observationsComments: MNRAS in pressSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)
Relativistic amplification boosts the contribution of the jet base to the total emission in blazars, thus making single dish observations useful and practical to characterise their physical state, particularly during episodes of enhanced multi-wavelength activity. Following the detection of a new gamma-ray source by Fermi-LAT in July 2017, we observed S4 0444+63 in order to secure its identification as a gamma-ray blazar. We conducted observations with the Medicina and Noto radio telescopes at 5, 8, and 24 GHz for a total of 12 epochs between 2017 August 1 and 2018 September 22. We carried out the observations with on-the-fly cross scans and reduced the data with our newly developed Cross-scan Analysis Pipeline, which we present here in detail for the first time. We found the source to be in an elevated state of emission at radio wavelength, compared to historical values, which lasted for several months. The maximum luminosity was reached on 2018 May 16 at 24 GHz, with $L_{24}=(1.7\pm0.3)\times10^{27}\ \mathrm{W\,Hz}^{-1}$; the spectral index was found to evolve from slightly rising to slightly steep. Besides the new observations, which have proved to be an effective and efficient tool to secure the identification of the source, additional single dish and very-long-baseline interferometry data provide further insight on the physics of the source. We estimate a synchrotron peak frequency $\nu_\mathrm{peak}=10^{12.97}$ Hz and a Doppler factor in excess of $\delta\sim5.0$, with both quantities playing a role in the gamma-ray emission from the source.
- [35] arXiv:2001.02914 [pdf, other]
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Title: First Resolved Dust Continuum Measurements of Individual Giant Molecular Clouds in the Andromeda GalaxyComments: ApJ, in pressSubjects: Astrophysics of Galaxies (astro-ph.GA)
In our local Galactic neighborhood, molecular clouds are best studied using a combination of dust measurements, to determine robust masses, sizes and internal structures of the clouds, and molecular-line observations to determine cloud kinematics and chemistry. We present here the first results of a program designed to extend such studies to nearby galaxies beyond the Magellanic Clouds. Utilizing the wideband upgrade of the Submillimeter Array (SMA) at 230 GHz we have obtained the first continuum detections of the thermal dust emission on sub-GMC scales ($\sim$ 15 pc) within the Andromeda galaxy (M31). These include the first resolved continuum detections of dust emission from individual GMCs beyond the Magellanic Clouds. Utilizing a powerful capability of the SMA, we simultaneously recorded CO(2-1) emission with identical $(u,\,v)$ coverage, astrometry and calibration, enabling the first measurements of the CO conversion factor, $\alpha_{\rm\,CO(2-1)}$, toward individual GMCs across an external galaxy. Our direct measurement yields an average CO--to--dust mass conversion factor of $\alpha^\prime_{\rm CO-dust} = 0.042\pm0.018$ $M_\odot$ (K km s$^{-1}$ pc$^2$)$^{-1}$ for the $J= 2-1$ transition. This value does not appear to vary with galactocentric radius. Assuming a constant gas-to-dust ratio of 136, the resulting $\alpha_{\rm CO}$ $=$ 5.7 $\pm$ 2.4 $M_\odot$ (K km s$^{-1}$ pc$^2$)$^{-1}$ for the 2-1 transition is in excellent agreement with that of Milky Way GMCs, given the uncertainties. Finally, using the same analysis techniques, we compare our results with observations of the local Orion molecular clouds, placed at the distance of M31 and simulated to appear as they would if observed by the SMA.
- [36] arXiv:2001.02916 [pdf, ps, other]
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Title: On the Metallicity Gradient in the Galactic DiskComments: 8 pages, 5 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
The problem of the chemical composition gradient in the galactic disk is studied based on a sample of metallicity estimates of open star clusters, using Gaia DR2-improved distance estimates. A clearly non-monotonic variation was observed in the average metallicity of clusters with increasing galactocentric distance. One can clearly see the metallicity jump of 0.22 in [Fe/H] at a Galactocentric distance of about 9.5 kpc, which appears to be linked to the outer boundary of the thinnest and youngest component of the galactic disk. The absence of a significant metallicity gradient in the internal (R<9 kpc) and external (R>10 kpc) regions of the disk demonstrates the absence of noticeable metal enrichment at times of the order of the ages corresponding to those of the disk regions under consideration. Observational data show that the disk experiences noticeable metal enrichment only during the starburst epochs. No significant dependence was found between the average metallicity and the age of the clusters.
- [37] arXiv:2001.02917 [pdf, other]
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Title: A blazar as the likely counterpart to 4FGL J0647.7-4418 instead of a gamma-ray binaryAuthors: Josep Martí, Estrella Sánchez-Ayaso, Pedro L. Luque-Escamilla, Josep M. Paredes, Valentí Bosch-Ramon, Robin H. D. CorbetComments: 7 pages, 9 Figures, accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The persistent gamma-ray source 4FGL J0647.7-4418 is tentatively associated in the latest Fermi catalogue with the sub-dwarf O-type X-ray binary HD 49798. However, an AGN candidate is also mentioned as an alternative identification in updated versions of the catalogue accompanying paper. If the first association were correct, this would add HD 49798 to the handful of currently known gamma-ray binaries and, therefore, represent a significant breakthrough not only because of a new member addition, but also because of the apparent white dwarf companion in this system. Despite these perspectives, here we show that the stellar association is likely wrong and that the proposed AGN object, well inside the Fermi 95% confidence ellipse, is a more conceivable counterpart candidate to the Fermi source due to its strong blazar similarities.
- [38] arXiv:2001.02939 [pdf, ps, other]
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Title: Sunspot Drawings at Kodaikanal Observatory: A Representative Results on Hemispheric Sunspot Numbers and Area MeasurementsAuthors: Ravindra B., Kumaravel Pichamani, Selvendran R., Joyce Samuel, Praveen Kumar, Nancy Jassoria, Navneeth R. SComments: 11 pages, 10 figures, accepted for publication in Astrophysics and space scienceSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The importance of the periodicity in sunspot appearance was well recognized by the mid of 19th century. Several observatories around the globe have made the record of sunspots in the form of drawings and preserved them safely for posterity. At the Kodaikanal Observatory (KO), the sunspot observations have begun in 1905. In those times observations were recorded on photographic plates and after the development of those plates in the laboratory, the drawings of the same were made on the Stonyhurst grids. In these drawings, called {\em sun charts}, different features on the sun's disk, e.g., sunspots, plages, filaments, prominences, etc. were clearly identified and visually marked with different colors. We have collected 111 years of sunspot drawing spanning over 10 solar cycles. These sunspot drawings were carefully stitched to make bound volumes, each for every 6-months. The drawings are kept at the Kodaikanal library for scientific use and analysis. In this article, we describe briefly the process of drawing, methods of counting sunspot numbers and measurement of sunspot area using square grids. We have collected the data for the Northern and Southern hemispheres separately. From the collected data, we compute the sunspot number and area and compare it with Royal Greenwich Observatory (RGO) and Sunspot Index and Long-term Solar Observations (SILSO) data. The results show that the measurement of the sunspot number is underestimated by about 40\%. The KO monthly averaged sunspot number data of both hemispheres is normalized with the RGO monthly averaged total sunspot number data.
- [39] arXiv:2001.02947 [pdf, ps, other]
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Title: Type Ia Supernova Sub-classes and Progenitor OriginAuthors: Ashley J. RuiterComments: 12 pages text + references (total 15 pages); 3 figures, 1 table. Proceedings article based on invited review talk for the IAU Symposium 357, "White Dwarfs as Probes of Fundamental Physics and Tracers of Planetary, Stellar, and Galactic Evolution," held in Hilo, Hawaii, 21-25 October 2019Subjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
This paper presents a short review on the current state of SN Ia progenitor origin. Type Ia supernova explosions are observed to be widely diverse in peak luminosity, lightcurve width and shape, spectral features, and host stellar population environment. In the last decade alone, theoretical simulations and observational data have come together to seriously challenge the long-standing paradigm that all SNe Ia arise from explosions of Chandrasekhar mass white dwarfs. In this review I highlight some of the major developments (and changing views) of our understanding of the nature of SN Ia progenitor systems. I give a brief overview of binary star configurations and their plausible explosion mechanisms, and infer links between some of the various (observationally-categorized) SN Ia sub-classes and their progenitor origins from a theoretical standpoint.
- [40] arXiv:2001.02955 [pdf, other]
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Title: Optical spectroscopy of type-2 LINERsComments: Accepted for publication in A&A. 20 pages, 20 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Type-2 Low-ionization Narrow Emission-line Regions (LINERs) have been optically classified with the Palomar data as not presenting a broad component in the Balmer emission lines associated to the Broad Line Region (BLR) of the Active Galactic Nuclei (AGN). We unveil the presence of different kinematic components of emission lines in the nuclear region of a sample of local (z$\leq$0.022) type-2 LINERs. We focus on the analysis of their true nature by means of the detection (or not) of a broad component originated in the BLR. Additionally, we search for the possible presence of non-rotational motions such as outflows. We have applied a decomposition of the nuclear emission lines using a spectroscopic analysis of the optical spectra of 9 type-2 LINERs of intermediate-resolution data retrieved from the Hubble Space Telescope (HST) archive. The study is completed with archival spectra from the Double Spectrograph from the Palomar Observatory. The emission line fitting reveals the presence of a broad component associated to the BLR in 6 out of the 9 galaxies for the space-based data, and for 2 out of the 8 from the ground-based spectra. The velocity dispersion of two galaxies (NGC 4486 and NGC 4594) measured in HST/STIS data suggest the presence of outflows. The results indicate that the spatial resolution plays a major role in the detection of the BLR, as it appears diluted in the ground-based data (even after removing stellar contribution). This is also true for the emission line diagnostics, as the contaminant light contributes to lower emission line ratios towards the star-forming area of standard BPTs. We propose to reclassify NGC4594 as a type-1 LINER, since a BLR component is seen in both space- and ground-based spectra. We find ambiguous results for the BLR component of NGC 4486. The modest outflow detection in our sample may indicate that they are not as frequent as for type-1 LINERs.
- [41] arXiv:2001.02971 [pdf, other]
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Title: The Onset of 3D Magnetic Reconnection and Heating in the Solar CoronaComments: 11 pages9 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph); Space Physics (physics.space-ph)
Magnetic reconnection, a fundamentally important process in many aspects of astrophysics, is believed to be initiated by the tearing instability of an electric current sheet, a region where magnetic field abruptly changes direction and electric currents build up. Recent studies have suggested that the amount of magnetic shear in these structures is a critical parameter for the switch-on nature of magnetic reconnection in the solar atmosphere, at fluid spatial scales much larger than kinetic scales. We present results of simulations of reconnection in 3D current sheets with conditions appropriate to the solar corona. Using high-fidelity simulations, we follow the evolution of the linear and non-linear 3D tearing instability, leading to reconnection. We find that, depending on the parameter space, magnetic shear can play a vital role in the onset of significant energy release and heating via non-linear tearing. Two regimes in our study exist, dependent on whether the current sheet is longer or shorter than the wavelength of the fastest growing parallel mode (in the corresponding infinite system), thus determining whether sub-harmonics are present in the actual system. In one regime, where the fastest growing parallel mode has sub-harmonics, the non-linear interaction of these sub-harmonics and the coalescence of 3D plasmoids dominates the non-linear evolution, with magnetic shear playing only a weak role in the amount of energy released. In the second regime, where the fastest growing parallel mode has no-sub-harmonics, then only strongly sheared current sheets, where oblique mode are strong enough to compete with the dominant parallel mode, show any significant energy release. We expect both regimes to exist on the Sun, and so our results have important consequences for the the question of reconnection onset in different solar physics applications.
- [42] arXiv:2001.02973 [pdf, ps, other]
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Title: Examining the secondary product origin of cosmic ray positrons with the latest AMS-02 dataComments: Submitted to AAS journals on November 18, 2019 (the original version was submitted on July 20, 2019)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
Measurements of cosmic-ray (CR) positron fraction by PAMELA and other experiments have found an excess above 10 GeV relative to the standard predictions for secondary production in the interstellar medium (ISM). Although the excess has been mostly suggested to arise from some primary sources of positrons (such as pulsars and or annihilating dark matter particles), the almost constant flux ratio of $e^{+}/ \bar{p}$ argues for an alternative possibility that the excess positrons and antiprotons up to the highest energies are secondary products generated in hadronic interactions. Recently, Yang \& Aharonian (2019) revisit this possibility by assuming the presence of an additional population of CR nuclei sources. Here we examine this secondary product scenario using the \texttt{DRAGON} code, where the radiative loss of positrons is taken into account consistently. We confirm that the CR proton spectrum and the antiproton data can be explained by assuming the presence of an additional population of CR sources. However, the corresponding positron spectrum deviates from the measured data significantly above 100 GeV due to the strong radiative cooling. This suggests that, although hadronic interactions can explain the antiproton data, the corresponding secondary positron flux is still not enough to account for the AMS data. Hence contribution from some primary positron sources, such as pulsars or dark matter, is non-negligible.
- [43] arXiv:2001.02984 [pdf, other]
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Title: Merger rate distribution of primordial black hole binaries with electric chargesComments: 2 figures, 18 pagesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
We consider gravitational radiation and electromagnetic radiation from point mass binary with electric charges in a Keplerian orbit, and calculate the merger rate distribution of primordial black hole binaries with charges and a general mass function by taking into account gravitational torque and electromagnetic torque by the nearest primordial black hole. We apply the formalism to the extremal charged case and find that $\alpha=-(m_i+m_j)^2\partial^2 \ln {\cal R}(m_i,m_j)/\partial m_i \partial m_j=12/11$, which is independent of the mass function.
- [44] arXiv:2001.02990 [pdf, other]
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Title: Analysing the Main Belt asteroid distributions by waveletsComments: 27 pages, 16 figures, 3 tables; submitted to Celestial Mechanics & Dynamical AstronomySubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We perform statistical wavelet analysis of the Main Belt asteroids, seeking statistically significant asteroid families. The goal is to test the new wavelet analysis algorithm and to compare its results with more traditional methods like the hierarchic clustering. We first consider several 1D distributions for various physical and orbital parameters of asteroids. Then we consider three bivariate distributions for the three orbital parameters $(a,e,i)$ taken pairwisely. The full 3D analysis of this space is not available here, but based on the 2D results we perform a disentangling of overlapped 2D families and derive total of $44$ 3D families with confirmed statistical significance.
- [45] arXiv:2001.03005 [pdf]
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Title: A dozen new dwarf galaxy candidates in the Local VolumeComments: 11 pages, 9 figures, 1 tableSubjects: Astrophysics of Galaxies (astro-ph.GA)
We carried out a survey of low-surface-brightness companions around nine luminous Local Volume galaxies using long exposures with small amateur telescopes. We found 12 low- and very low-surface-brightness objects around the galaxies: NGC 628, NGC 2337, NGC 3368, NGC 3521, NGC 4236, NGC 4258, NGC 4594, NGC 5055, and NGC 6744 situated within 12 Mpc from us. Assuming the dwarf candidates are satellites of the neighbouring massive galaxies, their absolute B magnitudes are in the range of [-8.9, -13.0], linear diameters are [0.6 - 2.7] kpc, and the mean surface brightnesses are [25.1 - 27.5] mag/sq.arecsec. The mean linear projected separation of satellite candidates from the host galaxies is 83 kpc.
- [46] arXiv:2001.03028 [pdf, other]
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Title: Cepheids under the magnifying glass -- not so simple, after all!Authors: Richard I. AndersonComments: 6 pages, 4 figures. Proceedings article for keynote presentation given at "Stars and their variability observed from space", held 19 to 23 August 2019 in Vienna, AustriaSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Classical Cepheids are blue loop stars that have famously been dubbed "magnifying glasses of stellar evolution" and have been studied for a long time. As more and more precise observations of Cepheids are secured over ever-increasing temporal baselines, our ignorance of the physics governing these crucial stars is becoming increasingly clear. Thus, it is time to turn up the magnification and investigate the limitations of our understanding of classical pulsators. Of course, classical Cepheids are also standard candles thanks to the Leavitt law that allows to measure distances in the nearby Universe. Nowadays, Cepheids serve as the backbone of a precisely calibrated distance ladder that allows to measure Hubble's constant (H0) to better than 2%, thus providing crucial constraints for precision cosmology. The recently established discord among H0 values measured in the late-time Universe and inferred from observations of the early Universe requires utmost diligence in estimating systematic uncertainties in order to strengthen the significance of the results. In this presentation I focus on two main aspects of recent Cepheid-related research. First, I present the Geneva Cepheid Radial Velocity survey (GE-CeRVS) and an update on the modulated spectroscopic variability exhibited by the 4 d Cepheid QZ Normae based on 8 years of monitoring. Then, I discuss some efforts directed towards a 1% H0 measurement needed for understanding the cosmological implications of discordant H0 values. Finally, I argue that now is a particularly opportune time to leverage the synergies between stellar physics and observational cosmology.
- [47] arXiv:2001.03034 [pdf, other]
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Title: Evolution of MAXI J1631-479 during the January 2019 outburst observed by INTEGRAL/IBISAuthors: M. Fiocchi, F. Onori, A. Bazzano, A.J. Bird, A. Bodaghee, P. A. Charles, V. A. Lepingwell, A. Malizia, N. Masetti, L. Natalucci, P. UbertiniComments: MNRAS acceptedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We report on a recent bright outburst from the new X-ray binary transient MAXI J1631-479, observed in January 2019. In particular, we present the 30-200 keV analysis of spectral transitions observed with INTEGRAL/IBIS during its Galactic Plane monitoring program. In the MAXI and BAT monitoring period, we observed two different spectral transitions between the high/soft and low/hard states. The INTEGRAL spectrum from data taken soon before the second transition, is best described by a Comptonised thermal component with an electron temperature of 30 keV and a high luminosity value of 3x10^38 erg/s in 2-200 keV energy range (assuming a distance of 8 kpc). During the second transition, the source shows a hard, power-law spectrum. The lack of high energy cut-off indicates that the hard X-ray spectrum from MAXI J1631-479 is due to a non-thermal emission. Inverse Compton scattering of soft X-ray photons from a non-thermal or hybrid thermal/non-thermal electron distribution can explain the observed X-ray spectrum although a contribution to the hard X-ray emission from a jet cannot be determined at this stage. The outburst evolution in the hardness-intensity diagram, the spectral characteristics and the rise and decay times of the outburst are suggesting this system is a black hole candidate.
- [48] arXiv:2001.03066 [pdf, other]
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Title: Efficient Dust Ring Formation in Misaligned Circumbinary DiscsComments: Accepted for publication in MNRAS, 11 pages, 9 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Binary systems exert a gravitational torque on misaligned discs orbiting them, causing differential precession which may produce disc warping and tearing. While this is well understood for gas-only discs, misaligned cirumbinary discs of gas and dust have not been thoroughly investigated. We perform SPH simulations of misaligned gas and dust discs around binaries to investigate the different evolution of these two components. We choose two different disc aspect ratios: A thin case for which the gas disc always breaks, and a thick one where a smooth warp develops throughout the disc. For each case, we run simulations of five different dust species with different degrees of coupling with the gas component, varying in Stokes number from 0.002 (strongly coupled dust) to 1000 (effectively decoupled dust). We report two new phenomena: First, large dust grains in thick discs pile up at the warp location, forming narrow dust rings, due to a difference in precession between the gas and dust components. These pile ups do not form at gas pressure maxima, and hence are different from conventional dust traps. This effect is most evident for St ~ 10 - 100. Second, thin discs tear and break only in the gas, while dust particles with St > 10 form a dense dust trap due to the steep pressure gradient caused by the break in the gas. We find that dust with St < 0.02 closely follow the gas particles, for both thin and thick discs, with radial drift becoming noticeable only for the largest grains in this range.
- [49] arXiv:2001.03080 [pdf, other]
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Title: The X-Shooter Spectral Library (XSL): Data Release 2Authors: Anaïs Gonneau, M. Lyubenova, A. Lançon, S. C. Trager, R. F. Peletier, A. Arentsen, Y. -P. Chen, P. R. T. Coelho, M. Dries, J. Falcón-Barroso, P. Prugniel, P. Sánchez-Blázquez, A. Vazdekis, K. VerroComments: Main paper: 16 pages, Full list of stars from pages 21 to 34, Typical XSL spectra on Figure 10 page 10Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We present the second data release (DR2) of the X-Shooter Spectral Library (XSL), which contains all the spectra obtained over the six semesters of that program. This release supersedes our first data release from Chen et al. 2014, with a larger number of spectra (813 observations of 666 stars) and with a more extended wavelength coverage as the data from the near-infrared arm of the X-Shooter spectrograph are now included. The DR2 spectra then consist of three segments that were observed simultaneously and, if combined, cover the range between $\sim$300 nm and $\sim$2.45 $\mu$m at a spectral resolving power close to $R=10\,000$. The spectra were corrected for instrument transmission and telluric absorption, and they were also corrected for wavelength-dependent flux-losses in 85% of the cases. On average, synthesized broad-band colors agree with those of the MILES library and of the combined IRTF and Extended IRTF libraries to within $\sim\!1$%. The scatter in these comparisons indicates typical errors on individual colors in the XSL of 2$-$4 %. The comparison with 2MASS point source photometry shows systematics of up to 5% in some colors, which we attribute mostly to zero-point or transmission curve errors and a scatter that is consistent with the above uncertainty estimates. The final spectra were corrected for radial velocity and are provided in the rest-frame (with wavelengths in air). The spectra cover a large range of spectral types and chemical compositions (with an emphasis on the red giant branch), which makes this library an asset when creating stellar population synthesis models or for the validation of near-ultraviolet to near-infrared theoretical stellar spectra across the Hertzsprung-Russell diagram.
- [50] arXiv:2001.03086 [pdf, other]
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Title: Broad-line Region of the Quasar PG 2130+099 from a Two-Year Reverberation Mapping Campaign with High CadenceAuthors: Chen Hu (1), Yan-Rong Li (1), Pu Du (1), Zhi-Xiang Zhang (1,2), Sha-Sha Li (1,2), Ying-Ke Huang (1,2), Kai-Xing Lu (3), Jin-Ming Bai (3), Luis C. Ho (4,5), Wei-Hao Bian (6), Michael S. Brotherton (7), Ye-Fei Yuan (8), Jesús Aceituno (9,10), Hartmut Winkler (11), Jian-Min Wang (1,2,12) (SEAMBH collaboration) ((1) Institute of High Energy Physics, China, (2) University of Chinese Academy of Sciences, China, (3) Yunnan Observatories, China, (4) Kavli Institute for Astronomy and Astrophysics, China, (5) Peking University, China, (6) Nanjing Normal University, China, (7) University of Wyoming, USA, (8) University of Science and Technology of China, China, (9) Centro Astronomico Hispano Alemán, Spain, (10) Instituto de Astrofísica de Andalucía, Spain, (11) University of Johannesburg, South Africa, (12) National Astronomical Observatories of China, China)Comments: 15 pages, 11 figures, accepted for publication in The Astrophysical JournalSubjects: Astrophysics of Galaxies (astro-ph.GA)
As one of the most interesting Seyfert 1 galaxies, PG 2130+099 has been the target of several reverberation mapping (RM) campaigns over the years. However, its measured broad H$\beta$ line responses have been inconsistent, with time lags of $\sim$200 days, $\sim$25 days, and $\sim$10 days being reported for different epochs while its optical luminosity changed no more than 40%. To investigate this issue, we conducted a new RM-campaign with homogenous and high cadence (about $\sim$3 days) for two years during 2017--2019 to measure the kinematics and structure of the ionized gas. We successfully detected time lags of broad H$\beta$, He II, He I, and Fe II lines with respect to the varying 5100\AA continuum, revealing a stratified structure that is likely virialized with Keplerian kinematics in the first year of observations, but an inflow kinematics of the broad-line region from the second year. With a central black hole mass of $0.97_{-0.18}^{+0.15}\times 10^7~M_{\odot}$, PG 2130+099 has an accretion rate of $10^{2.1\pm0.5}L_{\rm Edd}c^{-2}$, where $L_{\rm Edd}$ is the Eddington luminosity and $c$ is speed of light, implying that it is a super-Eddington accretor and likely possesses a slim, rather than thin, accretion disk. The fast changes of the ionization structures of the three broad lines remain puzzling.
- [51] arXiv:2001.03114 [pdf, ps, other]
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Title: Possible Formation Scenarios of ZTF J153932.16+502738.8-A Gravitational Source Close to the Peak of LISA's SensitivityComments: 10 pages, 8 figures, Accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
ZTF J153932.16+502738.8 (ZTFJ1539) is an eclipsing double-white-dwarf system with an orbital period of 6.91 minutes, and is a significant source of LISA detecting gravitational wave. However, the massive white dwarf (WD) with mass of about 0.61 M$_\odot$ has a high effective temperature (48900 K), and the lower mass WD with mass of about 0.21 M$_{\odot}$ has a low effective temperature($<$10000 K). It is challenging the popular theory of binary evolution. We investigate the formation of ZTFJ1539 via nova and Algol scenarios. Assuming that the massive WD in ZTFJ1539 just experiences a thermalnuclear runaway, nova scenario can explain the effective temperatures of two WDs in ZTFJ1539. However, in order to enlarging a semi-detached orbit of about 4---5 minutes to a detached orbit of about 7 minutes, nova scenario needs a much high kick velocity of about 200 km s$^{-1}$ during nova eruption. The high kick velocity can result in high eccentricity of about 0.2---0.6. Algol scenario can also produce ZTFJ1539 if we take a high efficient parameter for ejecting common envelope and enhance the mass-loss rate via stellar wind trigger by tidal effect.
- [52] arXiv:2001.03120 [pdf, other]
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Title: Field theoretic interpretations of interacting dark energy scenarios and recent observationsComments: 16 pages, 7 tables and 11 figures. Comments are welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
Cosmological models describing the non-gravitational interaction between dark matter and dark energy are based on some phenomenological choices of the interaction rates between dark matter and dark energy. There is no such guiding rule to select such rates of interaction. {\it In the present work we show that various phenomenological models of the interaction rates might have a strong field theoretical ground.} We explicitly derive several well known interaction functions between dark matter and dark energy under some special conditions and finally constrain them using the latest cosmic microwave background observations from final Planck legacy release together with baryon acoustic oscillations distance measurements. Our analyses report that one of the interacting functions is able to alleviate the $H_0$ tension. We also perform a Bayesian evidence analyses for all the models with reference to the $\Lambda$CDM model. From the Bayesian evidence analyses, although the reference scenario is preferred over the interacting scenarios, however, we found that two interacting models are close to the reference $\Lambda$CDM model.
- [53] arXiv:2001.03121 [pdf, other]
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Title: A Precise Analytical Approximation for the Deprojection of the Sérsic ProfileComments: 8 pages, 6 figures, 1 table, accepted by Astronomy & AstrophysicsSubjects: Astrophysics of Galaxies (astro-ph.GA)
The S\'ersic model is known to fit well the surface brightness (or surface density) profiles of elliptical galaxies and galaxy bulges, and possibly for dwarf spheroidal galaxies and globular clusters. The deprojected density and mass profiles are important for many astrophysical applications, in particular for mass-orbit modeling of these systems. However, the exact deprojection formula for the S\'ersic model employs special functions not available in most computer languages. We show that all previous analytical approximations to the 3D density profile are imprecise at low S\'ersic index ($n \lesssim 1.5$). We have derived a more precise analytical approximation to the deprojected S\'ersic density profile by fitting two-dimensional 10th-order polynomials to the differences of the logarithms of the numerical deprojection and of the analytical approximation by Lima Neto et al. (1999, LGM) of the density profile on one hand and of the mass profile on the other. Our LGM-based polynomial fits have typical relative precision better than $0.2\%$ for both density and mass profiles, for S\'ersic indices $0.5 \leq n \leq 10$ and radii $0.001 < r/R_{\rm e} < 1000$. Our approximation is much more precise than those of LGM, Simonneau & Prada (1999, 2004), Trujillo et al. (2002) for non-half-integer values of the index, and of Emsellem & van de Ven (2008) for non-one-tenth-integer values with $n \lesssim 3$, and are nevertheless more than $0.2\%$ precise for larger S\'ersic indices, for both density and mass profiles. An appendix compares the deprojected S\'ersic profiles with those of the popular simple models from Plummer (1911), Jaffe (1983), Hernquist (1990), Navarro et al. (1996), and Einasto (1965).
- [54] arXiv:2001.03126 [pdf, other]
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Title: Near-ultraviolet Transmission Spectroscopy of HD 209458b: Evidence of Ionized Iron Beyond the Planetary Roche LobeAuthors: Patricio E. Cubillos, Luca Fossati, Tommi Koskinen, Mitchell E. Young, Michael Salz, Kevin France, A. G. Sreejith, Carole A. HaswellComments: Accepted for publication at AAS JournalsSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
The inflated transiting hot Jupiter HD 209458b is one of the best studied objects since the beginning of exoplanet characterization. Transmission observations of this system between the mid infrared and the far ultraviolet have revealed the signature of atomic, molecular, and possibly aerosol species in the lower atmosphere of the planet, as well as escaping hydrogen and metals in the upper atmosphere. From a re-analysis of near-ultraviolet (NUV) transmission observations of HD 209458b, we detect ionized iron (Fe II) absorption in a 100 A-wide range around 2370 A, lying beyond the planetary Roche lobe. However, we do not detect absorption of equally strong Fe II lines expected to be around 2600 A. Further, we find no evidence for absorption by neutral magnesium (Mg I), ionized magnesium (Mg II), nor neutral iron (Fe I). These results avoid the conflict with theoretical models previously found by Vidal-Madjar et al. (2013), which detected Mg I but did not detect Mg II from this same data set. Our results indicate that hydrodynamic escape is strong enough to carry atoms as heavy as iron beyond the planetary Roche lobe, even for planets less irradiated than the extreme ultra-hot-Jupiters such as WASP-12b and KELT-9b. The detection of iron and non-detection of magnesium in the upper atmosphere of HD 209458b can be explained by a model in which the lower atmosphere forms (hence, sequesters) primarily magnesium-bearing condensates, rather than iron condensates. This is suggested by current microphysical models. The inextricable synergy between upper- and lower-atmosphere properties highlights the value of combining observations that probe both regions.
- [55] arXiv:2001.03134 [pdf, ps, other]
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Title: Sensor Distortion Effects in Photon Monte Carlo SimulationsAuthors: J. R. Peterson, P. O'Connor, A. Nomerotski, E. Magnier, J. G. Jernigan, J. Cheng, W. Cui, E. Peng, A. Rasmussen, G. SembroskiComments: Accepted for publication in ApJ; 13 pages, 12 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
We present a detailed method to simulating sensor distortions using a photon and electron Monte Carlo method. We use three dimensional electrostatic simulations to parameterize the perturbed electric field profile for non-ideal sensor details. We follow the conversion of simulated photons, and the subsequent response of the converted electrons to the electric field pattern. These non-ideal sensor details can be implemented efficiently in a Monte Carlo approach. We demonstrate that the non-ideal sensor distortions have a variety of observable consequence including the modification of the astrometric pattern, the distortion of the electron diffusion size and shape, and the distortion of flats. We show analytic validation of the diffusion physics, reproduce two kinds of edge distortion, and show qualitative validation of field-free regions, lithography errors, and fringing. We also demonstrate that there are two related effects of doping variation having different observable consequences. We show that field distortions from accumulated electrons lead to intensity-dependent point-spread-functions and the sub-linear variance in flats. The method is implemented in the Photon Simulator (PhoSim) and the code is publically available.
- [56] arXiv:2001.03135 [pdf, other]
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Title: X-ray Detected AGN in SDSS Dwarf GalaxiesComments: 19 pages, 12 figures, 1 table. Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
In this work we present a robust quantification of X-ray selected AGN in local ($z \leq 0.25$) dwarf galaxies ($M_\mathrm{*} \leq 3 \times 10^9 \mathrm{M_\odot}$). We define a parent sample of 4,331 dwarf galaxies found within the footprint of both the MPA-JHU galaxy catalogue (based on SDSS DR8) and 3XMM DR7, performed a careful review of the data to remove misidentifications and produced a sample of 61 dwarf galaxies that exhibit nuclear X-ray activity indicative of an AGN. We examine the optical emission line ratios of our X-ray selected sample and find that optical AGN diagnostics fail to identify 85% of the sources. We then calculated the growth rates of the black holes powering our AGN in terms of their specific accretion rates ($\propto L_\mathrm{X}/M_\mathrm{*}$, an approximate tracer of the Eddington ratio). Within our observed sample, we found a wide range of specific accretion rates. After correcting the observed sample for the varying sensitivity of 3XMM, we found further evidence for a wide range of X-ray luminosities and specific accretion rates, described by a power law. Using this corrected AGN sample we also define an AGN fraction describing their relative incidence within the parent sample. We found the AGN fraction increases with host galaxy mass (up to $\approx$ 6%) for galaxies with X-ray luminosities between $10^{39} \mathrm{erg/s}$ and $10^{42} \mathrm{erg/s}$, and by extrapolating the power law to higher luminosities, we found evidence to suggest the fraction of luminous AGN ($L_\mathrm{X} \geq 10^{42.4} \mathrm{erg/s}$) is constant out to $z \approx 0.7$.
- [57] arXiv:2001.03154 [pdf, other]
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Title: Correlation between Optical and UV Variability of QuasarsComments: 11 pages, 14 figures, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
The variability of quasars across multiple wavelengths is a useful probe of physical conditions in active galactic nuclei. In particular, variable accretion rates, instabilities, and reverberation effects in the accretion disk of a supermassive black hole (SMBH) are expected to produce correlated flux variations in UV and optical bands. Recent work has further argued that binary quasars should exhibit strongly correlated UV and optical periodicities. Strong UV-optical correlations have indeed been established in small samples of up to approximately 30 quasars with well-sampled light curves, and have extended the "bluer-when-brighter" trend previously found within the optical bands. Here we further test the nature of quasar variability by examining the observed-frame UV-optical correlations in a large sample of 1,315 bright quasars with overlapping UV and optical light curves for the Galaxy Evolution Explorer (GALEX) and the Catalina Real-time Transient Survey (CRTS), respectively. We find that strong correlations exist in this much larger sample, but we rule out, at approximately 95% confidence, the simple hypothesis that the intrinsic UV and optical variations of all quasars are fully correlated. Our results therefore imply the existence of physical mechanism(s) that can generate uncorrelated optical and UV flux variations.
Cross-lists for Fri, 10 Jan 20
- [58] arXiv:2001.02540 (cross-list from cond-mat.mes-hall) [pdf, other]
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Title: Nonlinear Effects in Superconducting Thin Film Microwave ResonatorsComments: 55 pages, 15 figuresSubjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Instrumentation and Methods for Astrophysics (astro-ph.IM); Superconductivity (cond-mat.supr-con)
We discuss how reactive and dissipative non-linearities affect the intrinsic response of superconducting thin-film resonators. We explain how most, if not all, of the complex phenomena commonly seen can be described by a model in which the underlying resonance is a single-pole Lorentzian, but whose centre frequency and quality factor change as external parameters, such as readout power and frequency, are varied. What is seen during a vector-network-analyser measurement is series of samples taken from an ideal Lorentzian that is shifting and spreading as the readout frequency is changed. According to this model, it is perfectly proper to refer to, and measure, the resonant frequency and quality factor of the underlying resonance, even though the swept-frequency curves appear highly distorted and hysteretic. In those cases where the resonance curve is highly distorted, the specific shape of the trajectory in the Argand plane gives valuable insights into the second-order physical processes present. We discuss the formulation and consequences of this approach in the case of non-linear kinetic inductance, two-level-system loss, quasiparticle generation, and a generic model based on a power-law form. The generic model captures the key features of specific dissipative non-linearities, but additionally leads to insights into how general dissipative processes create characteristic forms in the Argand plane. We provide detailed formulations in each case, and indicate how they lead to the wide variety of phenomena commonly seen in experimental data. We also explain how the properties of the underlying resonance can be extracted from this data. Overall, our paper provides a self-contained compendium of behaviour that will help practitioners interpret and determine important parameters from distorted swept-frequency measurements.
- [59] arXiv:2001.02763 (cross-list from physics.ins-det) [pdf, other]
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Title: An Impedance-Modulated Code-Division Microwave SQUID MultiplexerComments: 10 pages including references, 3 figures; submitted to Engineering Research ExpressSubjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Large arrays of cryogenic detectors, including transition-edge sensors (TESs) or magnetic micro-calorimeters (MMCs), are needed for future experiments across a wide range of applications. Complexities in integration and cryogenic wiring have driven efforts to develop cryogenic readout technologies with large multiplexing factors while maintaining minimal readout noise. One such example is the microwave SQUID multiplexer ($\mu$mux), which couples an incoming TES or magnetic calorimeter signal to a unique GHz-frequency resonance that is modulated in frequency. Here, we present a hybrid scheme combining the microwave SQUID multiplexer with code division multiplexing: the impedance-modulated code-division multiplexer (Z-CDM), which may enable an order of magnitude increase in multiplexing factor particularly for low-bandwidth signal applications.
- [60] arXiv:2001.02765 (cross-list from physics.comp-ph) [pdf, other]
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Title: Direct Calculation of Self-Gravitational Force for Infinitesimally Thin Gaseous Disks Using Adaptive Mesh RefinementComments: 16 pagesJournal-ref: The Astrophysical Journal Supplement Series, 244:26 (13pp), 2019 OctoberSubjects: Computational Physics (physics.comp-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Yen et al. (2012) advanced a direct approach for the calculation of self-gravitational force to second order accuracy based on uniform grid discretization. This method improves the accuracy of N-body calculation by using exact integration of kernel functions and employing the Fast Fourier Transform (FFT) to reduce complexity of computation to nearly linear. This direct approach is free of artificial boundary conditions, however, the applicability is limited by the uniform discretization of grids. We report here an advancement in the direct method with the implementation of adaptive mesh refinement (AMR) and maintaining second-order accuracy, which breaks the barrier set by uniform grid discretization. The adoption of graphic process units (GPUs) can significantly speed up the computation and make application of this method possible to astrophysical systems of gaseous disk galaxies and protoplanetary disks.
- [61] arXiv:2001.02833 (cross-list from gr-qc) [pdf, ps, other]
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Title: Signatures of Extended Theories of Gravity in Black Hole OscillationsAuthors: Arthur G SuvorovComments: 8 pages. To appear in the proceedings of the 6th Conference of the Polish Society on RelativitySubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
In general relativity, the Kerr metric uniquely represents the geometry surrounding an isolated, rotating black hole. An identification of significant non-Kerr features in some astrophysical source would then provide a `smoking-gun' for the break-down of general relativity in the strong-field regime. On the other hand, Kerr black holes are common to many other theories of gravity, and thus a validation of the Kerr metric does not necessarily favour general relativity amongst all possibilities. The nature of gravitational perturbations will however differ between different theories of gravity. Future precision tests involving gravitational waves from oscillating black holes, such as identifications of the quasi-normal mode spectrum from ring-down, will thus be able to probe the underlying theory, even if the object is Kerr. Here, we write down the equations governing metric perturbations of a Kerr black hole in $f(R)$ gravity in a form that is more conducive to numerical study.
- [62] arXiv:2001.02897 (cross-list from hep-th) [pdf, ps, other]
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Title: Second law of black hole thermodynamicsComments: 7 pages, 1 figureSubjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); Statistical Mechanics (cond-mat.stat-mech); General Relativity and Quantum Cosmology (gr-qc); Quantum Physics (quant-ph)
If simple entropy in the Bekenstein-Hawking area law for a black hole is replaced with 'negative' quantum conditional entropy, which quantifies quantum entanglement, of positive-energy particles of the black hole relative to its outside, a paradox with the original pair-creation picture of Hawking radiation, the first law for black hole mechanics and quantum mechanics is resolved. However, there was no way to judge experimentally which area law is indeed adopted by black holes. Here, with the no-hair conjecture, we derive the perfect picture of a second law of black hole thermodynamics from the modified area law, rather than Bekenstein's generalized one from the original area law. The second law is testable with an event horizon telescope, in contrast to Bekenstein's. If this is confirmed, the modified area law is exalted to the first example of fundamental equations in physics which cannot be described without the concept of quantum information.
- [63] arXiv:2001.02986 (cross-list from gr-qc) [pdf, other]
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Title: Concerns regarding the use of black hole shadows as standard rulersComments: 12 pages, 1 figure, comments are welcomeSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)
Recently, Tsupko et al. have put forward the very interesting proposal to use the shadows of high-redshift supermassive black holes (SMBHs) as standard rulers. This would in principle allow us to probe the expansion history within a redshift range which would otherwise be challenging to access. In this short note, we critically examine this proposal, and identify a number of important issues which had been previously overlooked. These range from difficulties in obtaining reliable SMBH mass estimates and reaching the required angular resolution, to an insufficient knowledge of the accretion dynamics of high-redshift SMBHs, to weak lensing effects leading to typical angular deflections much larger than the SMBH shadow angular sizes. While these issues would currently appear to prevent high-redshift SMBH shadows from being used as robust standard rulers, we hope that our pointing them out early will help in making such a probe theoretically mature by the time it will be experimentally feasible.
- [64] arXiv:2001.03061 (cross-list from physics.space-ph) [pdf, other]
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Title: Magnitude and direction of the local interstellar magnetic field inferred from Voyager 1 and 2 interstellar data and global heliospheric modelComments: 5 pages + 2 appendixesSubjects: Space Physics (physics.space-ph); Solar and Stellar Astrophysics (astro-ph.SR)
In this Letter, we provide constraints on the direction and magnitude of the pristine (i.e., unperturbed by the interaction with the Sun) local interstellar magnetic field. The constraints are based on analysis of the interstellar magnetic field components at the heliopause measured by magnetometer instruments on board Voyager 1 and 2 spacecraft. The analysis was performed with the help of our kinetic-magnetohydrodynamical (MHD) model of the global heliosphere. The model shows that the solar-induced disturbances of the interstellar magnetic field are extended relatively far from the Sun up to 400-500 AU. The field is draped around the heliopause and compressed. By comparison of the model results with Voyager data we found that the model provides results comparable with the data for the interstellar magnetic field of
$B_{LISM}$ = 3.7-3.8 $\mu$G in magnitude and directed towards $\approx$125$^\circ$ in longitude, and $\approx$37$^\circ$ in latitude in the heliographic inertial (HGI) coordinate system. - [65] arXiv:2001.03116 (cross-list from gr-qc) [pdf, other]
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Title: Deep learning for clustering of continuous gravitational wave candidatesSubjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM); Data Analysis, Statistics and Probability (physics.data-an)
In searching for continuous gravitational waves over very many ($\approx 10^{17}$) templates , clustering is a powerful tool which increases the search sensitivity by identifying and bundling together candidates that are due to the same root cause. We implement a deep learning network that identifies clusters of signal candidates in the output of continuous gravitational wave searches and assess its performance.
Replacements for Fri, 10 Jan 20
- [66] arXiv:1803.02397 (replaced) [pdf, other]
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Title: Markov chain Monte Carlo population synthesis of single radio pulsars in the GalaxyComments: Accepted for publication in MNRASSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)
- [67] arXiv:1905.00436 (replaced) [pdf, other]
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Title: The bias of cosmic voids in the presence of massive neutrinosAuthors: Nico Schuster, Nico Hamaus, Alice Pisani, Carmelita Carbone, Christina D. Kreisch, Giorgia Pollina, Jochen WellerComments: 23 pages, 18 figuresJournal-ref: JCAP12(2019)055Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [68] arXiv:1905.11426 (replaced) [pdf, other]
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Title: Heavy dark matter particle annihilation in dwarf spheroidal galaxies: radio signals at the SKA telescopeComments: 17 pages, 14 figures, accepted in Physical Review DSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
- [69] arXiv:1906.07750 (replaced) [pdf, other]
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Title: The Breakthrough Listen Search for Intelligent Life: Observations of 1327 Nearby Stars over 1.10-3.45 GHzAuthors: Danny C. Price, J. Emilio Enriquez, Bryan Brzycki, Steve Croft, Daniel Czech, David DeBoer, Julia DeMarines, Griffin Foster, Vishal Gajjar, Nectaria Gizani, Greg Hellbourg, Howard Isaacson, Brian Lacki, Matt Lebofsky, David H. E. MacMahon, Imke de Pater, Andrew P. V. Siemion, Dan Werthimer, James A. Green, Jane F. Kaczmarek, Ronald J. Maddalena, Stacy Mader, Jamie Drew, S. Pete WordenComments: Accepted to The Astronomical Journal (AJ)Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [70] arXiv:1907.03642 (replaced) [pdf, other]
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Title: The Abundance and Structure of Subhaloes near the Free Streaming Scale and Their Impact on Indirect Dark Matter SearchesComments: 11 pages, 9 figures, accepted by MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [71] arXiv:1907.03732 (replaced) [pdf, other]
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Title: Signatures of the Core-Powered Mass-Loss Mechanism in the Exoplanet Population: Dependence on Stellar Properties and Observational PredictionsComments: 16 pages and 11 figures. Submitted to MNRAS. Revised versionSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [72] arXiv:1907.04236 (replaced) [pdf, other]
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Title: Primordial black holes from the preheating instabilityComments: 29 pages plus appendices (total 42 pages), 14 figures, matches published versionSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
- [73] arXiv:1907.05475 (replaced) [pdf, other]
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Title: Astrophysical limits on very light axion-like particles from Chandra grating spectroscopy of NGC 1275Authors: Christopher S. Reynolds, M.C. David Marsh, Helen R. Russell, Andrew C. Fabian, Robyn N. Smith, Francesco Tombesi, Sylvain VeilleuxComments: 12 pages, 6 figures, Accepted for publication in The Astrophysical JournalSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)
- [74] arXiv:1907.08642 (replaced) [pdf, other]
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Title: An Updated SMC and Magellanic Bridge Catalog of Star Clusters, Associations and Related ObjectsAuthors: Eduardo Bica, Pieter Westera, Leandro de O. Kerber, Bruno Dias, Francisco Maia, João F. C. Santos Jr., Beatriz Barbuy, Raphael A. P. OliveiraComments: 21 pages, 13 figures and 4 tables. Updated to match accepted version in AJ. The updated catalog is provided in full as ancillary fileSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [75] arXiv:1907.12029 (replaced) [pdf, ps, other]
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Title: Hybrid star within the framework of a lowest-order constraint variational methodComments: 25 pages, 9 figures, 8 TablesJournal-ref: Phys. Rev. D 101, 023004 (2020)Subjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [76] arXiv:1908.10813 (replaced) [pdf, ps, other]
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Title: Quasinormal Modes of Generalized Black Holes: delta-Kerr SpacetimeComments: 21 pages, 1 figure; v2: expanded version; v3: minor improvements, references added; v4: expanded version to appear in CQGSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
- [77] arXiv:1908.10969 (replaced) [pdf, other]
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Title: Tilting Ice Giants with a Spin-Orbit ResonanceComments: 16 pages, 8 figures, accepted for publication in ApJ, minor editsSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [78] arXiv:1909.07560 (replaced) [pdf, other]
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Title: The composition of MarsAuthors: Takashi Yoshizaki (1), William F. McDonough (1, 2, 3) ((1) Department of Earth Science, Tohoku University, Japan, (2) Department of Geology, University of Maryland, College Park, USA, (3) Research Center of Neutrino Sciences, Tohoku University, Japan)Comments: 81 pages, 30 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [79] arXiv:1909.08609 (replaced) [pdf, other]
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Title: Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWCAuthors: HAWC Collaboration: A.U. Abeysekara, A. Albert, R. Alfaro, J.R. Angeles Camacho, J.C. Arteaga-Velázquez, K.P. Arunbabu, D. Avila Rojas, H.A. Ayala Solares, V. Baghmanyan, E. Belmont-Moreno, S.Y. BenZvi, C. Brisbois, K.S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, S. Dichiara, B.L. Dingus, M.A. DuVernois, J.C. Díaz-Vélez, R.W. Ellsworth, K. Engel, C. Espinoza, H. Fleischhack, N. Fraija, A. Galván-Gámez, D. Garcia, J.A. García-González, F. Garfias, M.M. González, J.A. Goodman, J.P. Harding, S. Hernandez, J. Hinton, B. Hona, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, A. Jardin-Blicq, V. Joshi, S. Kaufmann, D. Kieda, A. Lara, et al. (52 additional authors not shown)Comments: Accepted by Physical Review LettersSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [80] arXiv:1910.00232 (replaced) [pdf, ps, other]
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Title: Partition Function of the Bose-Einstein Condensed Dark Matter and the Modified Gross-Pitaevskii EquationAuthors: A.V. NazarenkoComments: 1 figure; to appear in Int. J. Mod. Phys. D (2020)Subjects: Astrophysics of Galaxies (astro-ph.GA); Other Condensed Matter (cond-mat.other)
- [81] arXiv:1910.01638 (replaced) [pdf, ps, other]
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Title: Particle and entropy production in the Running Vacuum UniverseComments: Accepted in Gen.Rel.Grav. Extended discussion, references addedSubjects: 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)
- [82] arXiv:1910.07723 (replaced) [pdf, other]
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Title: Detection of Late-Time Optical Emission from SN 1941C in NGC 4136Comments: 7 pages, 5 figures, revised and accepted by ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [83] arXiv:1910.09637 (replaced) [pdf, other]
- [84] arXiv:1910.12953 (replaced) [pdf, other]
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Title: Cold Clouds as Cosmic-Ray DetectorsAuthors: Shmuel BialyComments: Accepted for publication in Nature Communications Physics. (editorial style changes following Nature publishing requirements, and some typo corrections)Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
- [85] arXiv:1910.13451 (replaced) [pdf, other]
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Title: The KLEVER Survey: Spatially resolved metallicity maps and gradients in a sample of 1.2 < z < 2.5 lensed galaxiesAuthors: Mirko Curti, Roberto Maiolino, Michele Cirasuolo, Filippo Mannucci, Rebecca J. Williams, Matt Auger, Amata Mercurio, Connor Hayden-Pawson, Giovanni Cresci, Alessandro Marconi, Francesco Belfiore, Michele Cappellari, Claudia Cicone, Fergus Cullen, Massimo Meneghetti, Kazuaki Ota, Yingjie Peng, Max Pettini, Mark Swinbank, Paulina TroncosoComments: Main text: 23 pages, 11 figures. Appendix: 12 pages, 11 figures. Accepted for publication on MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [86] arXiv:1911.04271 (replaced) [pdf, other]
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Title: Modelling the chemical evolution of Zr, La, Ce and Eu in the Galactic discs and bulgeComments: 8 pages, 2 figures. Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [87] arXiv:1911.04497 (replaced) [pdf, other]
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Title: Testing self-interacting dark matter with galaxy warpsComments: v2: minor modifications + appendix with results in terms of the momentum transfer cross sectionSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
- [88] arXiv:1911.04793 (replaced) [pdf, other]
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Title: HD 117214 debris disk: scattered light images and constraints on the presence of planetsAuthors: N. Engler, C. Lazzoni, R. Gratton, J. Milli, H.M. Schmid, G. Chauvin, Q. Kral, N. Pawellek, P. Thébault, A. Boccaletti, M. Bonnefoy, S. Brown, T. Buey, F. Cantalloube, M. Carle, A. Cheetham, S. Desidera, M. Feldt, C. Ginski, D. Gisler, Th. Henning, S. Hunziker, A.M. Lagrange, M. Langlois, D. Mesa, M.R. Meyer, O. Moeller-Nilsson, J. Olofsson, C. Petit, S. Petrus, S.P. Quanz, E. Rickman, E. Stadler, T. Stolker, A. Vigan, F. Wildi, A. ZurloComments: 20 pagesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [89] arXiv:1912.07626 (replaced) [pdf, ps, other]
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Title: Baryon-Interacting Dark Matter: heating dark matter and the emergence of galaxy scaling relationsComments: 32 pages. v2: Minor edits, references addedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc)
- [90] arXiv:1912.08820 (replaced) [pdf, other]
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Title: Survival of Primordial Planetary Atmospheres: Photodissociation Driven Mass LossComments: Accepted by ApJ (26 pages, 2 figures, 3 tables)Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [91] arXiv:1912.10874 (replaced) [pdf]
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Title: Dispersed Matter Planet Project Discoveries of Ablating Planets Orbiting Nearby Bright StarsAuthors: Carole A. Haswell, Daniel Staab, John R. Barnes, Guillem Anglada-Escudé, Luca Fossati, James S. Jenkins, Andrew J. Norton, James P.J. Doherty, Joseph CooperComments: Accepted for publication by Nature Astronomy on 12th November 2019 (Main article, Methods and Supplementary Information; 42 pages, 15 figures, 5 tables)Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [92] arXiv:2001.00275 (replaced) [pdf, ps, other]
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Title: Reduction of the canonical Hamiltonian of the metric GR to its natural formAuthors: Alexei M. FrolovSubjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [93] arXiv:2001.00877 (replaced) [pdf, other]
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Title: BAT AGN Spectroscopic Survey -- XV: The High Frequency Radio Cores of Ultra-hard X-ray Selected AGNAuthors: Krista Lynne Smith, Richard F. Mushotzky, Michael Koss, Benny Trakhtenbrot, Claudio Ricci, O. Ivy Wong, Franz E. Bauer, Federica Ricci, Stuart Vogel, Daniel Stern, Meredith C. Powell, C. Meg Urry, Fiona Harrison, Julian Mejia-Restrepo, Kyuseok Oh, Junhyun Baek, Aeree ChungComments: 22 pages, 10 figures, 2 tables. Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [94] arXiv:2001.02211 (replaced) [pdf, other]
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Title: Spectrophotometric calibration of low-resolution spectraComments: Version submitted to A&A, minor modifications [spelling correction, updated acknowledgements, minor re-wording for clarity]Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [95] arXiv:2001.02243 (replaced) [pdf, other]
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Title: A Gaia-based catalog of candidate stripped nuclei and luminous globular clusters in the halo of Centaurus AAuthors: Karina T. Voggel, Anil C. Seth, David J. Sand, Allison Hughes, Jay Strader, Denija Crnojevic, Nelson CaldwellComments: Accepted to ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [96] arXiv:2001.02486 (replaced) [pdf, other]
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Title: Evidence for Galactic disc RR~Lyrae stars in the Solar neighbourhoodComments: 12 pages, 9 figures, Accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
- [97] arXiv:2001.02577 (replaced) [pdf, other]
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Title: Search for Nearby Earth Analogs. II. detection of five new planets, eight planet candidates, and confirmation of three planets around nine nearby M dwarfsAuthors: Fabo Feng, R. Paul Butler, Stephen A. Shectman, Jeffrey D. Crane, Steve Vogt, John Chambers, Hugh R. A. Jones, Sharon Xuesong Wang, Johanna K. Teske, Jenn Burt, Matias R. Diaz, Ian B. ThompsonComments: 38 pages, 31 figures, 4 tablesJournal-ref: 2020, ApJS, 246, 11Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
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