Astrophysics
New submissions
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New submissions for Fri, 10 Apr 20
- [1] arXiv:2004.04158 [pdf, other]
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Title: Disk formation and jet inclination effects in Common EnvelopesComments: 9 pages, 4 figures, 1 table; submitted to MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The evolution and physics of the common envelope (CE) phase are still not well understood. Jets launched from a compact object during this stage may define the evolutionary outcome of the binary system. We focus on the case in which jets are launched from a neutron star (NS) engulfed in the outer layers of a red giant (RG). We run a set of three-dimensional hydrodynamical simulations of jets with different luminosities and inclinations. The luminosity of the jet is self-regulated by the mass accretion rate and an efficiency $\eta$. Depending on the value of $\eta$ the jet can break out of the BHL bulge ("successful jet") and aligns against the incoming wind, in turn, it will realign in favour of the direction of the wind. The jet varies in size and orientation and may present quiescent and active epochs. The inclination of the jet and the Coriolis and centrifugal forces, only slightly affect the global evolution. As the accretion is hypercritical, and the specific angular momentum is above the critical value for the formation of a disk, we infer the formation of a disk and launching of jets. The disks' mass and size would be $\sim$10$^{-2}$~M$_\odot$ and $\gtrsim 10^{10}$ cm, and it may have rings with different rotation directions. In order to have a successful jet from a white dwarf, the ejection process needs to be very efficient ($\eta\sim$0.5). For main sequence stars, there is not enough energy reservoir to launch a successful jet.
- [2] arXiv:2004.04160 [pdf, other]
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Title: Molecular Cross Sections for High Resolution Spectroscopy of Super Earths, Warm Neptunes and Hot JupitersAuthors: Siddharth Gandhi, Matteo Brogi, Sergei N. Yurchenko, Jonathan Tennyson, Phillip A. Coles, Rebecca K. Webb, Jayne L. Birkby, Gloria Guilluy, George A. Hawker, Nikku Madhusudhan, Aldo S. Bonomo, Alessandro SozzettiComments: 16 pages, 11 figures, accepted for publication in MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
High resolution spectroscopy (HRS) has been used to detect a number of species in the atmospheres of hot Jupiters. Key to such detections is accurately and precisely modelled spectra for cross-correlation against the R$\gtrsim$20,000 observations. There is a need for the latest generation of opacities which form the basis for high signal-to-noise detections using such spectra. In this study we present and make publicly available cross sections for six molecular species, H$_2$O, CO, HCN, CH$_4$, NH$_3$ and CO$_2$ using the latest line lists most suitable for low- and high-resolution spectroscopy. We focus on the infrared (0.95-5~$\mu$m) and between 500-1500~K where these species have strong spectral signatures. We generate these cross sections on a grid of pressures and temperatures typical for the photospheres of super Earth, warm Neptunes and hot Jupiters using the latest H$_2$ and He pressure broadening. We highlight the most prominent infrared spectral features by modelling three representative exoplanets, GJ~1214~b, GJ~3470~b and HD~189733~b, which encompass a wide range in temperature, mass and radii. In addition, we verify the line lists for H$_2$O, CO and HCN with previous high resolution observations of hot Jupiters. However, we are unable to detect CH$_4$ with our new cross sections from HRS observations of HD~102195~b. These high accuracy opacities are critical for atmospheric detections with HRS and will be continually updated as new data becomes available.
- [3] arXiv:2004.04165 [pdf, other]
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Title: Distributed peer review enhanced with natural language processing and machine learningAuthors: Wolfgang E. Kerzendorf, Ferdinando Patat, Dominic Bordelon, Glenn van de Ven, Tyler A. PritchardComments: 20 pages including supplementary information. Constructive criticism more than welcome. Accepted and published in Nature AstronomyJournal-ref: Nature Astronomy 2020Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Physics and Society (physics.soc-ph)
While ancient scientists often had patrons to fund their work, peer review of proposals for the allocation of resources is a foundation of modern science. A very common method is that proposals are evaluated by a small panel of experts (due to logistics and funding limitations) nominated by the grant-giving institutions. The expert panel process introduces several issues - most notably: 1) biases introduced in the selection of the panel. 2) experts have to read a very large number of proposals. Distributed Peer Review promises to alleviate several of the described problems by distributing the task of reviewing among the proposers. Each proposer is given a limited number of proposals to review and rank. We present the result of an experiment running a machine-learning enhanced distributed peer review process for allocation of telescope time at the European Southern Observatory. In this work, we show that the distributed peer review is statistically the same as a `traditional' panel, that our machine learning algorithm can predict expertise of reviewers with a high success rate, and we find that seniority and reviewer expertise have an influence on review quality. The general experience has been overwhelmingly praised from the participating community (using an anonymous feedback mechanism).
- [4] arXiv:2004.04166 [pdf, other]
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Title: A new approach to modelling γ-ray burst afterglows: Using Gaussian processes to account for the systematicsComments: Submitted to MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The afterglow emission from gamma-ray bursts (GRBs) is a valuable source of information to understand the physics of these energetic explosions. The blast wave model has become the standard to describe the evolution of the afterglow emission over time and frequency. Thanks to recent developments in the theory of afterglows and numerical simulations of relativistic outflows, we are able to model the afterglow emission with realistic dynamics and radiative processes. Although the models agree with observations remarkably well, the afterglow emission still contains additional physics, instrumental systematics, and propagation effects which make the modelling of these events challenging. In this work, we present a new approach to modelling GRB afterglows, using Gaussian processes (GPs) to take into account systematics in the afterglow data. We show that, using this new approach, it is possible to obtain more reliable estimates of the explosion and microphysical parameters of GRBs. We present fit results for 5 long GRBs and find a preliminary correlation between the isotropic energetics and opening angles of GRBs, which confirms the idea of a common energy reservoir for the kinetic energy of long GRBs.
- [5] arXiv:2004.04167 [pdf, ps, other]
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Title: Radio Power from a Direct-Collapse Black Hole in CR7Comments: 4 pages, 2 figures, submitted to ApJLSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The leading contenders for the seeds of the first quasars are direct collapse black holes (DCBHs) formed during catastrophic baryon collapse in atomically-cooled halos at $z \sim$ 20. The discovery of the Ly$\alpha$ emitter CR7 at $z =$ 6.6 was initially held to be the first detection of a DCBH, although this interpretation has since been challenged on the grounds of Spitzer IRAC and Very Large Telescope X-Shooter data. Here we estimate the radio flux from a DCBH and a young supernova remnant in CR7, the latter of which can be confused with flux from a quasar. We find that a DCBH would emit a flux of 0.75 - 8.9 $\mu$Jy at 1.0 GHz, far greater than the nJy signal expected for a young supernova, so the detection of any radio emission from CR7 would confirm it to be the potential site of a DCBH. This flux could easily be detected by the next-generation Very Large Array and the Square Kilometer Array in the coming decade.
- [6] arXiv:2004.04171 [pdf, other]
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Title: Molecular clouds under the FUV feedback: factories of CO-dark gasComments: 15 pages, 9 figures, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
The star formation in molecular clouds is inefficient. The ionizing EUV radiation ($h \nu \geq 13.6$ eV) from young clusters has been considered as a primary feedback effect to limit the star formation efficiency (SFE). We here focus on effects of the stellar FUV radiation (6 eV $\leq h \nu \leq$ 13.6 eV) during the cloud disruption stage. The FUV radiation may further reduce the SFE via photoelectric heating, and it also affects the chemical states of the gas that is not converted to stars ("cloud remnants") via photodissociation of molecules. We have developed a one-dimensional semi-analytic model which follows the evolution of both the thermal and chemical structure of a photodissociation region (PDR) during the dynamical expansion of an HII region. We investigate how the FUV feedback limits the SFE, supposing that the star formation is quenched in the PDR where the temperature is above a threshold value (e.g., 100K). Our model predicts that the FUV feedback contributes to reduce the SFEs for the massive ($M_{\rm cl} \gtrsim 10^5 M_{\odot}$) clouds with the low surface densities ($\Sigma_{\rm cl} \lesssim 100$ M$_{\odot}$pc$^{-2}$). Moreover, we show that a large part of the H$_2$ molecular gas contained in the cloud remnants should be "CO-dark" under the FUV feedback for a wide range of cloud properties. Therefore, the dispersed molecular clouds are potential factories of the CO-dark gas, which returns into the cycle of the interstellar medium.
- [7] arXiv:2004.04176 [pdf, other]
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Title: Etching glass in the early Universe: Luminous HF and water emission in a QSO-SMG pair at z=4.7Authors: M. D. Lehnert (1), C. Yang (2), B. H. C. Emonts (3), A. Omont (1), E. Falgarone (4), P. Cox (1), P. Guillard (1)Comments: A&A accepted, several figures and it is relatively short, only 8 pagesSubjects: Astrophysics of Galaxies (astro-ph.GA)
(abridged) We present ALMA observations of hydrogen fluoride, HF J=1-0, H20 (202-211), and the 1.2 THz rest-frame continuum emission from the z=4.7 system BR1202-0725. BR1202-0725 is a galaxy group consisting of a QSO, a sub-millimeter galaxy (SMG), and two Ly-alpha emitters. We detected HF in emission in the QSO and possibly in absorption in the SMG, while water is detected in emission in both the QSO and SMG. The QSO is the most luminous HF emitter yet found and has the same ratio of HF emission line to infrared luminosity as a sample of local AGN and the Orion Bar. This consistency covers about 10 orders-of-magnitude in infrared luminosity, L_IR. Based on the conclusions of a study of HF emission in the Orion Bar and modeling, the HF emission in the QSO is either excited by collisions with electrons and H2 in molecular plasmas irradiated by the AGN and intense star formation or predominately by collisions with H2, with a modest contribution from electrons, in a relatively high temperature (~120 K), dense (~10^5 cm^-3) medium. Although HF should be an excellent tracer of molecular outflows, we do not find strong evidence for outflows in HF in either the QSO or the SMG. From a putative absorption feature in HF in the SMG, we estimate an upper limit on the outflow rate, dM/dt_outflow <~45 M_sun/yr. The ratio of the outflow rate to the star formation rate is <5% for the SMG. The broadness of the H2O line in the SMG, FWHM~1020 km/s, may suggest that either the gas on large scales (>4 kpc) is significantly more disturbed and turbulent due either to interactions and mass exchange with the other members of the group or to the dissipation of the energy of the intense star formation or both. The lack of significant molecular outflows in either source may imply that much of the energy from the intense star formation and AGN activity in this pair is being dissipated in their ISM.
- [8] arXiv:2004.04177 [pdf, other]
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Title: Inpainting via Generative Adversarial Networks for CMB data analysisComments: 19 pages, 21 figures. Prepared for submission to JCAP. All codes will be published after acceptanceSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Computer Vision and Pattern Recognition (cs.CV); Machine Learning (cs.LG); Computation (stat.CO)
In this work, we propose a new method to inpaint the CMB signal in regions masked out following a point source extraction process. We adopt a modified Generative Adversarial Network (GAN) and compare different combinations of internal (hyper-)parameters and training strategies. We study the performance using a suitable $\mathcal{C}_r$ variable in order to estimate the performance regarding the CMB power spectrum recovery. We consider a test set where one point source is masked out in each sky patch with a 1.83 $\times$ 1.83 squared degree extension, which, in our gridding, corresponds to 64 $\times$ 64 pixels. The GAN is optimized for estimating performance on Planck 2018 total intensity simulations. The training makes the GAN effective in reconstructing a masking corresponding to about 1500 pixels with $1\%$ error down to angular scales corresponding to about 5 arcminutes.
- [9] arXiv:2004.04179 [pdf, other]
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Title: Late X-ray flares from the interaction of a reverse shock with a stratified ejecta in GRB afterglows: simulations on a moving meshComments: 17 pages, 22 figures, Submitted to MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Late activity of the central engine is often invoked in order to explain the flares observed in the early X-ray afterglow of gamma-ray bursts, either in the form of an active neutron star remnant or (fall-back) accretion onto a black hole. However, these scenarios are not always plausible, in particular when flares are delayed to very late times after the burst. Recently, a new scenario was proposed that suggests X-ray flares can be the result of the passing of a long-lived reverse shock through a stratified ejecta, with the advantage that it does not require late-time engine activity.
In this work, we numerically demonstrate this scenario to be physically plausible, by performing onedimensional simulations of ejecta dynamics and emission using our novel moving-mesh relativistic hydrodynamics code. Improved efficiency and precision over previous work enables the exploration of a broader range of setups. We can introduce a more physically realistic description of the circumburst medium mass density. We can also locally trace the cooling of electrons when computing the broadband emission from these setups.
We show that the synchrotron cooling timescale can dominate the flare decay time if the stratification in the ejecta is constrained to a localised angular region inside the jet, with size corresponding to the relativistic causal connection angle, and that it corresponds to values reported in observations. We demonstrate that this scenario can produce a large range of observed flare times, suggesting a connection between flares and initial ejection dynamics rather than with late-time remnant activity. - [10] arXiv:2004.04185 [pdf, other]
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Title: Photochemistry of Anoxic Abiotic Habitable Planet Atmospheres: Impact of New H$_2$O Cross-SectionsAuthors: Sukrit Ranjan, Edward W. Schwieterman, Chester Harman, Alexander Fateev, Clara Sousa-Silva, Sara Seager, Renyu HuComments: At "minor comments" stage in review at ApJ. Comments/criticism/feedback solicited to improve the paper before it is fully finalizedSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We present a study of the photochemistry of abiotic habitable planets with anoxic CO$_2$-N$_2$ atmospheres. Such worlds are representative of early Earth, Mars and Venus, and analogous exoplanets. H$_2$O photodissociation controls the atmospheric photochemistry of these worlds through production of reactive OH, which dominates the removal of atmospheric trace gases. The near-UV (NUV; $>200$ nm) absorption cross-sections of H$_2$O play an outsized role in OH production; these cross-sections were heretofore unmeasured at habitable temperatures ($<373$ K). We present the first measurements of NUV H$_2$O absorption at $292$ K, and show it to absorb orders of magnitude more than previously assumed. To explore the implications of these new cross-sections, we employ a photochemical model; we first intercompare it with two others and resolve past literature disagreement. The enhanced OH production due to these higher cross-sections leads to efficient recombination of CO and O$_2$, suppressing both by orders of magnitude relative to past predictions and eliminating the low-outgassing "false positive" scenario for O$_2$ as a biosignature. Enhanced [OH] increases rainout of reductants to the surface, relevant to prebiotic chemistry, and may also suppress CH$_4$ and H$_2$; the latter depends on whether whether burial of reductants is inhibited on the underlying planet, as is argued for abiotic worlds. While we focus on CO$_2$-rich worlds, our results are relevant to anoxic planets in general. Overall, our work advances the state-of-the-art of photochemical models by providing crucial new H$_2$O cross-sections and resolving past disagreement in the literature, and suggests that detection of spectrally active trace gases like CO in rocky exoplanet atmospheres may be more challenging than previously considered.
- [11] arXiv:2004.04187 [pdf, other]
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Title: Possible Production of Solar Spicules by Microfilament EruptionsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We examine Big Bear Solar Observatory (BBSO) Goode Solar Telescope (GST) high-spatial resolution (0''.06), high-cadence (3.45 s), H-alpha-0.8 Angstrom images of central-disk solar spicules, using data of Samanta et al. (2019). We compare with coronal-jet chromospheric-component observations of Sterling et al. (2010a). Morphologically, bursts of spicules, referred to as "enhanced spicular activities" by Samanta et al. (2019), appear as scaled-down versions of the jet's chromospheric component. Both the jet and the enhanced spicular activities appear as chromospheric-material strands, undergoing twisting-type motions of ~20---50 km/s in the jet and ~20---30 km/s in the enhanced spicular activities. Presumably, the jet resulted from a minifilament-carrying magnetic eruption. For two enhanced spicular activities that we examine in detail, we find tentative candidates for corresponding erupting microfilaments, but not expected corresponding base brightenings. Nonetheless, the enhanced-spicular-activities' interacting mixed-polarity base fields, frequent-apparent-twisting motions, and morphological similarities to the coronal jet's chromospheric-temperature component, suggest that erupting microfilaments might drive the enhanced spicular activities but be hard to detect, perhaps due to H-alpha opacity. Degrading the BBSO/GST-image resolution with a 1''.0-FWHM smoothing function yields enhanced spicular activities resembling the "classical spicules" described by, e.g., Beckers (1968). Thus, a microfilament eruption might be the fundamental driver of many spicules, just as a minifilament eruption is the fundamental driver of many coronal jets. Similarly, a 0".5-FWHM smoothing renders some enhanced spicular activities to resemble previously-reported "twinned" spicules, while the full-resolution features might account for spicules sometimes appearing as 2D-sheet-like structures.
- [12] arXiv:2004.04195 [pdf, ps, other]
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Title: Thermodynamically consistent equation of state for an accreted neutron star crustComments: 11 pages, 5 figures, submitted to PRL on 2019-11-26Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
We study equation of state (EOS) of an accreting neutron star crust. Usually, such EOS is obtained assuming (implicitly) that the free (unbound) neutrons and nuclei in the inner crust move together. We argue, that this assumption violates the condition $\mu_n^\infty={\rm const}$, required for hydrostatic (and diffusion) equilibrium of unbound neutrons ($\mu^\infty_n$ is the redshifted neutron chemical potential). We construct a new EOS respecting this condition, working in the compressible liquid-drop approximation. We demonstrate that it is close to the catalyzed EOS in most part of the inner crust, being very different from EOSs of accreted crust discussed in the literature. In particular, the pressure at the outer-inner crust interface does not coincide with the neutron drip pressure, usually calculated in the literature, and is determined by hydrostatic (and diffusion) equilibrium conditions within the star. We also find an instability at the bottom of fully accreted crust that transforms nuclei into homogeneous nuclear matter. It guarantees that the structure of fully accreted crust remains self-similar during accretion.
- [13] arXiv:2004.04202 [pdf, other]
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Title: The ELM Survey South I: An Effective Search for Extremely Low Mass White DwarfsComments: 25 pages, 15 figures, 8 tablesSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We begin the search for extremely-low mass ($M\leq0.3M_{\odot}$, ELM) white dwarfs (WDs) in the southern sky based on photometry from the VST ATLAS and SkyMapper surveys. We use a similar color-selection method as the Hypervelocity star survey. We switched to an astrometric selection once Gaia Data Release 2 became available. We use the previously known sample of ELM white dwarfs to demonstrate that these objects occupy a unique parameter space in parallax and magnitude. We use the SOAR 4.1m telescope to test the Gaia-based selection, and identify more than two dozen low-mass white dwarfs, including 6 new ELM white dwarf binaries with periods as short as 2 h. The better efficiency of the Gaia-based selection enables us to extend the ELM Survey footprint to the southern sky. We confirm one of our candidates, J0500$-$0930, to become the brightest ($G=12.6$ mag) and closest ($d=72$ pc) ELM white dwarf binary currently known. Remarkably, the Transiting Exoplanet Survey Satellite (TESS) full-frame imaging data on this system reveals low-level ($<0.1$%) but significant variability at the orbital period of this system ($P=9.5$ h), likely from the relativistic beaming effect. TESS data on another system, J0642$-$5605, reveals ellipsoidal variations due to a tidally distorted ELM WD. These demonstrate the power of TESS full-frame images in confirming the orbital periods of relatively bright compact object binaries.
- [14] arXiv:2004.04210 [pdf, other]
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Title: Studying the Landau mass parameter of the extended sigma-model for neutron star matterComments: 8 pages, 9 figures. Proceedings of The International Bogolyubov Conference on Problems of Theoretical and Mathematical Physics, MIRAN & JINR, September 9-13, 2019Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory (nucl-th)
We present a Bayesian analysis of the Landau mass within the extended $\sigma$-$\omega$ model for neutron star matter. To this purpose, we consider the mass measurement of the object PSR 0740+6620, the tidal deformability estimation from the GW170817 and the mass-radius estimate of PSR J0030+0451 by NICER. Using Landau mass as free parameter of the theory, we tested the prediction power to find the best value fo this nuclear parameter of the Bayesian method.
- [15] arXiv:2004.04230 [pdf, other]
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Title: Impossible moons -- Transit timing effects that cannot be due to an exomoonComments: MNRAS, 11 pages, 5 figures, 1 tableSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Exomoons are predicted to produce transit timing variations (TTVs) upon their host planet. Unfortunately, so are many other astrophysical phenomena - most notably other planets in the system. In this work, an argument of reductio ad absurdum is invoked, by deriving the transit timing effects that are impossible for a single exomoon to produce. Our work derives three key analytic tests. First, one may exploit the fact that a TTV signal from an exomoon should be accompanied by transit duration variations (TDVs), and that one can derive a TDV floor as a minimum expected level of variability. Cases for which the TDV upper limit is below this floor can thus be killed as exomoon candidates. Second, formulae are provided for estimating whether moons are expected to be 'killable' when no TDVs presently exist, thus enabling the community to estimate whether it's even worth deriving TDVs in the first place. Third, a TTV ceiling is derived, above which exomoons should never be able to produce TTV amplitudes. These tools are applied to a catalog of TTVs and TDVs for two and half thousand Kepler Objects Interest, revealing over two hundred cases that cannot be due to a moon. These tests are also applied to the exomoon candidate Kepler-1625b i, which comfortably passes the criteria. These simple analytic results should provide a means of rapidly rejecting putative exomoons and streamlining the search for satellites.
- [16] arXiv:2004.04236 [pdf, ps, other]
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Title: Rotation of Low-Mass Stars in Taurus with K2Authors: L. M. Rebull, J. R. Stauffer, A. M. Cody, L. A. Hillenbrand, J. Bouvier, N. Roggero, T. J. DavidComments: 39 pages, 12 figures. Accepted by AJSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We present an analysis of K2 light curves (LCs) from Campaigns 4 and 13 for members of the young ($\sim$3 Myr) Taurus association, in addition to an older ($\sim$30 Myr) population of stars that is largely in the foreground of the Taurus molecular clouds. Out of 156 of the highest-confidence Taurus members, we find that 81\% are periodic. Our sample of young foreground stars is biased and incomplete, but nearly all (37/38) are periodic. The overall distribution of rotation rates as a function of color (a proxy for mass) is similar to that found in other clusters: the slowest rotators are among the early M spectral types, with faster rotation towards both earlier FGK and later M types. The relationship between period and color/mass exhibited by older clusters such as the Pleiades is already in place by Taurus age. The foreground population has very few stars, but is consistent with the USco and Pleiades period distributions. As found in other young clusters, stars with disks rotate on average slower, and few with disks are found rotating faster than $\sim$2 d. The overall amplitude of the light curves decreases with age and higher mass stars have generally lower amplitudes than lower mass stars. Stars with disks have on average larger amplitudes than stars without disks, though the physical mechanisms driving the variability and the resulting light curve morphologies are also different between these two classes.
- [17] arXiv:2004.04241 [pdf, other]
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Title: Recent developments in determining the evolution of magnetic OB starsComments: Conference proceedings: "Stellar Magnetic Fields - A workshop in honor of the career and contributions of John Landstreet", London, Canada, 2019 (to be published in the Proceedings of the Polish Astronomical Society)Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
We review recent developments in determining the evolution of magnetic massive OB stars. One of the important scientific questions is the completeness and the detection limits of contemporaneous spectropolarimetric surveys across the HR diagram. We present the characteristics of the MiMeS survey of O-type stars, and how the limits of the current available observations warrant the design of new high-precision surveys that target the older O-type star population. Another important question is whether the presence of the magnetic fields changes stellar evolutionary tracks in a significant way, hence leading to a wrong determination of stellar parameters. We review new evolution models that include the effect of magnetic wind quenching, and suppression of convection in the iron opacity peak zone.
- [18] arXiv:2004.04248 [pdf, ps, other]
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Title: The intermediate nebular phase of SN 2014J: onset of clumping as the source of recombinationAuthors: P. A. Mazzali, I. Bikmaev, R. Sunyaev, C. Ashall, S. Prentice, M. Tanaka, E. Irtuganov, S. Melnikov, R. ZhuchkovComments: Accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
At the age of about 1 year, the spectra of most Type Ia supernovae are dominated by strong forbidden nebular emission lines of FeII and FeIII. Later observations (at about 2 years) of the nearby SN 2011fe showed an unexpected shift of ionization to FeI and FeII. Spectra of the very nearby SN Ia 2014J at an intermediate phase (1 - 1.5 years) that are presented here show a progressive decline of FeIII emission, while FeI is not yet strong. The decrease in ionization can be explained if the degree of clumping in the ejecta increases significantly at ~1.5 years, at least in the Fe-dominated zone. Models suggest that clumps remain coherent after about one year, behaving like shrapnel. The high density in the clumps, combined with the decreasing heating rate, would then cause recombination. These data may witness the phase of transition from relatively smooth ejecta to the very clumpy morphology that is typical of SN remnants. The origin of the increased clumping may be the development of local magnetic fields.
- [19] arXiv:2004.04253 [pdf, ps, other]
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Title: Extragalactic cosmic rays diffusing from two populations of sourcesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We consider the possibility of explaining the observed spectrum and composition of the cosmic rays with energies above $10^{17}$ eV in terms of two different extragalactic populations of sources in the presence of a turbulent intergalactic magnetic field (including also a fading Galactic cosmic-ray component). The populations are considered to be the superposition of different nuclear species having rigidity dependent spectra. The first extragalactic population is dominant in the energy range $10^{17}$ to $10^{18}$ eV and consists of sources having a relatively large density ($> 10^{-3}$ Mpc$^{-3}$) and a steep spectrum. The second extragalactic population dominates the cosmic ray flux above few EeV, it has a harder spectral slope and has a high-energy cutoff at few $Z$ EeV (where $eZ$ is the associated cosmic ray charge). This population has a lower density of sources ($<10^{-4}$ Mpc$^{-3}$), so that the typical intersource separation is larger than few tens of Mpc, being significantly affected by a magnetic horizon effect that strongly suppresses its flux for energies below $\sim Z$ EeV. We discuss how this scenario could be reconciled with the values of the cosmic-ray source spectral indices that are expected to result from the diffusive shock acceleration mechanism.
- [20] arXiv:2004.04263 [pdf, other]
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Title: Strong chemical tagging with APOGEE: 21 candidate star clusters that have dissolved across the Milky Way discAuthors: Natalie Price-Jones Jo Bovy, Jeremy J. Webb, Carlos Allende Prieto, Rachael Beaton, Joel R. Brownstein, Roger E. Cohen, Katia Cunha, John Donor, Peter M. Frinchaboy, D. A. García-Hernández, Richard R. Lane, Steven R. Majewski, David L. Nidever, Alexandre Roman-LopesComments: 15 pages, 9 figures, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Chemically tagging groups of stars born in the same birth cluster is a major goal of spectroscopic surveys. To investigate the feasibility of such strong chemical tagging, we perform a blind chemical tagging experiment on abundances measured from APOGEE survey spectra. We apply a density-based clustering algorithm to the eight dimensional chemical space defined by [Mg/Fe], [Al/Fe], [Si/Fe], [K/Fe], [Ti/Fe], [Mn/Fe], [Fe/H], and [Ni/Fe], abundances ratios which together span multiple nucleosynthetic channels. In a high quality sample of 182,538 giant stars, we detect twenty-one candidate clusters with more than fifteen members. Our candidate clusters are more chemically homogeneous than a population of non-member stars with similar [Mg/Fe] and [Fe/H], even in abundances not used for tagging. Group members are consistent with having the same age and fall along a single stellar-population track in logg vs. Teff space. Each group's members are distributed over multiple kpc, and the spread in their radial and azimuthal actions increases with age. We qualitatively reproduce this increase using N-body simulations of cluster dissolution in Galactic potentials that include transient winding spiral arms. Observing our candidate birth clusters with high-resolution spectroscopy in other wavebands to investigate their chemical homogeneity in other nucleosynthetic groups will be essential to confirming the efficacy of strong chemical tagging. Our initially spatially-compact but now widely dispersed candidate clusters will provide novel limits on chemical evolution and orbital diffusion in the Galactic disc, and constraints on star formation in loosely-bound groups.
- [21] arXiv:2004.04269 [pdf, other]
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Title: Scaling laws for the geometry of an impact-induced magma oceanAuthors: Miki Nakajima, Gregor J. Golabek, Kai Wünnemann, David C. Rubie, Christoph Burger, Henry J. Melosh, Seth A. Jacobson, Lukas Manske, Scott D. HullComments: Submitted to Earth and Planetary Science Letters with revisionsSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Growing protoplanets experience a number of impacts during the accretion stage. A large impactor hits the surface of a protoplanet and produces a magma ocean, where the impactor's iron emulsifies and experiences metal-silicate equilibration with the mantle of the protoplanet while it descends towards the base of the magma ocean. This process repeatedly occurs and determines the chemical compositions of both mantle and core. The partitioning is controlled by parameters such as the equilibration pressure and temperature, which are often associated with or assumed to be proportional to the pressure and temperature at the base of the magma ocean. The pressure and temperature depend on both the depth and shape of a magma ocean because a spatially confined magma ocean, namely, a melt pool, can have a larger equilibrium pressure than a radially uniform (global) magma ocean even if their melt volumes are the same. Here, we develop scaling laws for (1) the total internal energy gain due to an impact, and (2) the heat distribution within the mantle based on more than 100 smoothed particle hydrodynamic (SPH) simulations. We use Legendre polynomials to describe these scaling laws and determine their coefficients by linear regression, minimizing the error between our model and SPH simulations. The input parameters are the impact angle, total mass, impact velocity, and impactor-to-total mass ratio. We find that the internal energy gain by a large impact is well characterized by the summation of the kinetic energy and accretional potential energy release as a function of the impact angle. We determine that the equilibrium pressure at the base of a melt pool can be higher (by $10-50 \%$) than those obtained from conventional radially-uniform global magma ocean models. These melt scaling laws are publicly available on GitHub (https://github.com/mikinakajima/MeltScalingLaw).
- [22] arXiv:2004.04277 [pdf, other]
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Title: GRANDMA Observations of Advanced LIGO's and Advanced Virgo's Third Observational CampaignAuthors: S. Antier, S. Agayeva, M. Almualla, S. Awiphan, A. Baransky, K. Barynova, S. Beradze, M. Blasek, M. Boer, O. Burkhonov, N. Christensen, A. Coleiro, D. Corre, M. W. Coughlin, H. Crisp, T. Dietrich, J.-G. Ducoin, P.-A. Duverne, G. Marchal-Duval, B. Gendre, P. Gokuldass, H. B. Eggenstein, L. Eymar, P. Hello, E. J. Howell, N. Ismailov, D. A. Kann, S. Karpov, A. Klotz, N. Kochiashvili, C. Lachaud, N. Leroy, W. L. Lin, W. X. Li, M. Masek, J. Mo, R. Menard, D. Morris, K. Noysena, N. B. Orange, M. Prouza, R. Rattanamala, T. Sadibekova, D. Saint-Gelais, M. Serrau, A. Simon, C. Stachie, C. C. Thone, Y. Tillayev, D. Turpin, A. de Ugarte Postigo, V. Vasylenko, Z. Vidadi, M. Was, X. F. Wang, J. J. Zhang, T. M. Zhang, X. H. ZhangComments: 31 pages, 15 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
GRANDMA is a network of 25 telescopes of different sizes, including both photometric and spectroscopic facilities. The network aims to coordinate follow-up observations of gravitational-wave candidate alerts, especially those with large localisation uncertainties, to reduce the delay between the initial detection and the optical confirmation. In this paper, we detail GRANDMA's observational performance during Advanced LIGO/Advanced Virgo Observing Run 3 (O3), focusing on the second part of O3; this includes summary statistics pertaining to coverage and possible astrophysical origin of the candidates. To do so, we quantify our observation efficiency in terms of delay between gravitational-wave candidate trigger time, observations, and the total coverage. Using an optimised and robust coordination system, GRANDMA followed-up about 90 % of the gravitational-wave candidate alerts, i.e. 49 out of 56 candidates. This led to coverage of over 9000 deg2 during O3. The delay between the gravitational-wave candidate trigger and the first observation was below 1.5 hour for 50 % of the alerts. We did not detect any electromagnetic counterparts to the gravitational-wave candidates during O3, likely due to the very large localisation areas (on average thousands of degrees squares) and relatively large distance of the candidates (above 200 Mpc for 60 % of BNS candidates). We derive constraints on potential kilonova properties for two potential binary neutron star coalescences (GW190425 and S200213t), assuming that the events' locations were imaged.
- [23] arXiv:2004.04280 [pdf]
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Title: Positron Processes in the SunAuthors: Nat GopalswamyComments: 14 pages, 6 figures, 1 table, to appear in AtomsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
Positrons play a major role in the emission of solar gamma-rays at energies from a few hundred keV to >1 GeV. Although the processes leading to positron production in the solar atmosphere are well known, the origin of the energetic particles that interact with the ambient particles is poorly understood. With the aim of understanding the full gamma-ray spectrum of the Sun, I review the key emission mechanisms that contribute to the observed gamma-ray spectrum, focusing on the ones involving positrons. In particular, I review the processes involved in the 0.511 MeV positron annihilation line and the positronium continuum emissions at low energies, and the pion continuum emission at high energies in solar eruptions. It is thought that particles accelerated at the flare reconnection and at the shock driven by coronal mass ejections are responsible for the observed gamma-ray features. Based on some recent developments I suggest that energetic particles from both mechanisms may contribute to the observed gamma-ray spectrum.
- [24] arXiv:2004.04335 [pdf, ps, other]
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Title: Comments on "Type II migration strikes back -- An old paradigm for planet migration in discs" by Scardoni et alComments: 4 pages, 1 figure, accepted for publication in MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
In the conventional view of type~II migration, a giant planet migrates inward in the viscous velocity of the accretion disc in the so-call disc-dominate case. Recent hydrodynamic simulations, however, showed that planets migrate with velocities much faster than the viscous one in massive discs. Such fast migration cannot be explained by the conventional picture. Scardoni et al. (2020) has recently argued this new picture. By carrying out similar hydrodynamic simulations, they found that the migration velocity slows down with time and eventually reaches the prediction by the conventional theory. they interpreted the fast migration as an initial transient one and concluded that the conventional type II migration is realised after the transient phase. We show that the migration velocities obtained by Scardoni et al. (2020) are consistent with the previous simulations even in the transient phase that they proposed. We also find that the transient fast migration proposed by Scardoni et al. (2020) is well described by a new model of Kanagawa et al. (2018). The new model can appropriately describe significant inward migration during the initial transient phase that Scardoni et al. (2020) termed. Hence, we conclude that the time-variation of the transient migration velocity is due to the changes of the orbital radius of the planet and its background surface density during the migration.
- [25] arXiv:2004.04337 [pdf, ps, other]
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Title: GeV emission of gamma-ray binary with pulsar scenarioSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We study GeV emission from gamma-ray binaries by assuming that the compact object is a young pulsar. We assume that the relativistic unshocked pulsar wind with Lorentz factor of 10^4~5 can produce the GeV emission by the inverse-Compton scattering process in the dense soft-photon field of the companion star. The travel distance of the unshocked pulsar wind that moves toward the observer depends on the orbital phase of the pulsar. We discuss that the orbital modulation of the GeV emission is a result of combination of the effects of the travel distance of the unshocked pulsar wind and of the anisotropic soft-photon field of the companion star. In this paper, we study how the effect of the travel distance of the unshocked pulsar wind affects to the orbital modulation of GeV emission. We apply our scenario to two gamma-ray binaries, LMC P3 and 4FGL J1405.5-6119. We find that with the suggested system parameters of LMC P3, the observed amplitude of the orbital modulation and the peak width are more consistent with the model light curve by taking into account the effect of the travel distance. For LMC P3, we analyze the GeV spectrum with 8-years Fermi-LAT data and discuss the broadband emission process in X-ray to TeV energy bands. We predict a possible system geometry for 4FGL J1405.5-6119 by fitting the GeV light curve. Key words: shock waves, gamma-rays: stars, stars: massive stars: mass-loss, stars: neutron
- [26] arXiv:2004.04360 [pdf, other]
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Title: The Lyman Continuum Escape Fraction of Galaxies and AGN in the GOODS FieldsAuthors: Brent M. Smith (1), Rogier A. Windhorst (1), Seth H. Cohen (1), Anton M. Koekemoer (2), Rolf A. Jansen (1), Cameron White (3), Sanchayeeta Borthakur (1), Nimish Hathi (2), Linhua Jiang (4), Michael Rutkowski (5), Russell E. Ryan Jr. (2), Akio K. Inoue (6 and 7), Robert W. O'Connell (8), John W. MacKenty (2), Christopher J. Conselice (9), Joseph I. Silk (10) ((1) ASU/SESE, Tempe, AZ, USA, (2) STScI, Baltimore, MD, USA, (3) UA, Tucson, AZ, USA, (4) PKU/Kavli, Beijing, China, (5) MSU Mankato, Mankato, MN, USA, (6) Waseda U., Tokyo, Japan, (7) Waseda RISE, Tokyo, Japan, (8) UVa, Charlottesville, VA, USA, (9) UNott, Nottingham, UK, (10) JHU, Baltimore, MD, USA)Comments: 36 pages, 17 figures, 5 tables. Accepted for publication in The Astrophysical JournalSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We present our analysis of the LyC emission and escape fraction of 111 spectroscopically verified galaxies with and without AGN from 2.26$\,$$<$$\,$$z$$\,$$<$4.3. We extended our ERS sample from $\href{https://iopscience.iop.org/article/10.3847/1538-4357/aaa3dc}{\mathrm{Smith\ et\ al.\ 2018}}$ with 64 galaxies in the GOODS North and South fields using WFC3/UVIS F225W, F275W, and F336W mosaics we independently drizzled using the HDUV, CANDELS, and UVUDF data. Among the 17 AGN from the 111 galaxies, one provided a LyC detection in F275W at $m_{\mathrm{AB}}$$\,$=$\,$23.19$\,$mag (S/N$\,$$\simeq$$\,$133) and $GALEX$ NUV at $m_{\mathrm{AB}}$$\,$=$\,$23.77$\,$mag (S/N$\,$$\simeq$$\,$13). We simultaneously fit $SDSS$ and $Chandra$ spectra of this AGN to an accretion disk and Comptonization model and find $f_{\mathrm{esc}}$ values of $f_{\mathrm{esc}}^{\mathrm{F275W}}\!\simeq\!28^{+20}_{-4}$% and $f_{\mathrm{esc}}^{\mathrm{NUV}}\!\simeq\!30^{+22}_{-5}$%. For the remaining 110 galaxies, we stack image cutouts that capture their LyC emission using the F225W, F275W, and F336W data of the GOODS and ERS samples, and both combined, as well as subsamples of galaxies with and without AGN, and $all$ galaxies. We find the stack of 17 AGN dominate the LyC production from $\langle z\rangle$$\,$$\simeq$$\,$2.3$-$4.3 by a factor of $\sim$10 compared to all 94 galaxies without AGN. While the IGM of the early universe may have been reionized mostly by massive stars, there is evidence that a significant portion of the ionizing energy came from AGN.
- [27] arXiv:2004.04363 [pdf, other]
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Title: Volumetric Star Formation Prescriptions in Vertically Resolved Edge-on GalaxiesComments: 19 pages, 18 figures, Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We measure the gas disc thicknesses of the edge-on galaxy NGC 4013 and the less edge-on galaxies (NGC 4157 and 5907) using CO (CARMA/OVRO) and/or HI (EVLA) observations. We also estimate the scale heights of stars and/or the star formation rate (SFR) for our sample of five galaxies using Spitzer IR data (3.6 $\mu$m and 24 $\mu$m). We derive the average volume densities of the gas and the SFR using the measured scale heights along with radial surface density profiles. Using the volume density that is more physically relevant to the SFR than the surface density, we investigate the existence of a volumetric star formation law (SFL), how the volumetric SFL is different from the surface-density SFL, and how the gas pressure regulates the SFR based on our galaxy sample. We find that the volumetric and surface SFLs in terms of the total gas have significantly different slopes, while the volumetric and surface SFLs in terms of the molecular gas do not show any noticeable difference. The volumetric SFL for the total gas has a flatter power-law slope of 1.26 with a smaller scatter of 0.19 dex compared to the slope (2.05) and the scatter (0.25 dex) of the surface SFL. The molecular gas SFLs have similar slopes of 0.78 (volume density) and 0.77 (surface density) with the same rms scatter. We show that the interstellar gas pressure is strongly correlated with the SFR but find no significant difference between the correlations based on the volume and surface densities.
- [28] arXiv:2004.04382 [pdf, other]
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Title: Artificial Neural Network Spectral Light Curve Template for Type Ia Supernovae and its Cosmological ConstraintsComments: 8 pages two columns, 17 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
The spectral energy distribution (SED) sequence for type Ia supernovae (SN Ia) is modeled by an artificial neural network. The SN Ia luminosity is characterized as a function of phase, wavelength, a color parameter and a decline rate parameter. After training and testing the neural network, the SED sequence could give both the spectrum with wavelength range from 3000\AA~to 8000\AA~ and the light curve with phase from 20 days before to 50 days after the maximum luminosity for the supernovae with different colors and decline rates. Therefore, we call this the Artificial Neural Network Spectral Light Curve Template (ANNSLCT) model. We retrain the Joint Light-curve Analysis (JLA) supernova sample by using the ANNSLCT model and obtain the parameters for each supernova to make a constraint on the cosmological $\Lambda$CDM model. We find that the best fitting values of these parameters are almost the same as those from the JLA sample trained with the Spectral Adaptive Lightcurve Template 2 (SALT2) model. So we believe that the ANNSLCT model could be used to analyze a large number of SN Ia multi-color light curves measured in the current and future observational projects.
- [29] arXiv:2004.04395 [pdf, other]
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Title: Turnaround density as a probe of the cosmological constantComments: 5 pages, 3 figures, submitted to A&ALSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Spherical collapse predicts that a single value of the turnaround density (average matter density within the scale on which a structure detaches from the Hubble flow) characterizes all cosmic structures at the same redshift. It has been recently shown by Korkidis et al. that this feature persists in complex non-spherical galaxy clusters identified in N-body simulations. Here we show that the low-redshift evolution of the turnaround density constrains the cosmological parameters, and that it can be used to derive a local constraint on $\Omega_\Lambda$ alone, independent of $\Omega_m$. The turnaround density thus provides a promising new way to exploit upcoming large cosmological datasets.
- [30] arXiv:2004.04399 [pdf, other]
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Title: First radio evidence for impulsive heating contribution to the quiet solar coronaComments: Accepted for publication in ApJ LettersSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
This letter explores the relevance of nanoflare based models for heating the quiet sun corona. Using metrewave data from the Murchison Widefield Array, we present the first successful detection of impulsive emissions down to flux densities of $\sim$mSFU, about two orders of magnitude weaker than earlier attempts. These impulsive emissions have durations $\lesssim 1$s and are present throughout the quiet solar corona. The fractional time occupancy of these impulsive emissions at a given region is $\lesssim 10\%$. The histograms of these impulsive emissions follow a powerlaw distribution and show signs of clustering at small timescales. Our estimate of the energy which must be dumped in the corona to generate these impulsive emissions is consistent with the coronal heating requirements. Additionally, the statistical properties of these impulsive emissions are very similar to those recently determined for magnetic switchbacks by the Parker Solar Probe (PSP). We hope that this work will lead to a renewed interest in relating these weak impulsive emissions to the energy deposited in the corona, the quantity of physical interesting from a coronal heating perspective, and explore their relationship with the magnetic switchbacks observed by the PSP.
- [31] arXiv:2004.04401 [pdf, ps, other]
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Title: Dynamic kink instability and transverse motions of solar spiculesAuthors: T. V. ZaqarashviliComments: 5 pages, 4 figures, accepted in ApJLSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Hydrodynamic jets are unstable to the kink instability (m=1 mode in cylindrical geometry) owing to the centripetal force, which increases the transverse displacement of the jet. When the jet moves along a magnetic field, then the Lorentz force tries to decrease the displacement and stabilises the instability of sub-Alfvenic flows. The threshold of the instability depends on the Alfven Mach number (the ratio of Alfven and jet speeds). We suggest that the dynamic kink instability may be of importance to explain observed transverse motions of type II spicules in the solar atmosphere. We show that the instability may start for spicules which rise up at the peripheries of vertically expanding magnetic flux tubes owing to the decrease of the Alfven speed in both, the vertical and the radial directions. Therefore, inclined spicules may be more unstable and have more higher transverse speeds. Periods and growth times of unstable modes in the conditions of type II spicules have the values of 30 s and 25-100 s, respectively, which are comparable to the life time of the structures. This may indicate to the interconnection between high speed flow and rapid disappearance of type II spicules in chromospheric spectral lines.
- [32] arXiv:2004.04430 [pdf, ps, other]
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Title: Toward experimental observations of induced Compton scattering by high-power laser facilitiesComments: Accepted for publication in PTEP, 10 pages, 3 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Induced Compton scattering (ICS) is a nonlinear interaction between intense electromagnetic radiation and a rarefied plasma.
Although the magnetosphere of pulsars is a potential cite at which ICS occurs in nature, the ICS signatures have not been discovered so far.
One of the reasons for non-detection of the ICS signatures is that we still do not attain the concrete understanding of such nonlinear plasma interactions because of their nonlinear nature and of the lack of experimental confirmations.
Here, we propose a possible approach to understand ICS experimentally in laboratories, especially, with the use of the up-to-date short-pulse lasers.
We find that the scattered light of ICS has characteristic signatures in the spectrum.
The signatures will be observed in some current laser facilities.
The characteristic spectrum is quantitatively predictable and we can diagnose the properties of the scattering plasma from the signatures. - [33] arXiv:2004.04437 [pdf, other]
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Title: On rare core collapse supernovae inside planetary nebulaeComments: To be submitted in two days to allow comments by readersSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
We conduct simulations of white dwarf (WD) - neutron star (NS) reverse evolution, and conclude that a core collapse supernova (CCSN) explosion might occur inside a planetary nebula (PN) only if a third star forms the PN. In the WD-NS reverse evolution the primary star evolves and transfers mass to the secondary star, forms a PN, and leaves a WD remnant. If the mass transfer brings the secondary star to have a mass of >8Mo before it develops a helium core, it explodes as a CCSN and leaves a NS remnant. Using the Modules for Experiments in Stellar Astrophysics (MESA) we find that in the reverse evolution the time period from the formation of the PN by the primary star to the explosion of the secondary star is longer than a million years. By that time the PN has long dispersed into the interstellar medium. If we start with two stars that are too close in mass to each other, then the mass transfer takes place after the secondary star has developed a helium core and it ends forming a PN and a WD. The formation of a CCSN inside a PN (so called CCSNIP) requires the presence of a third star, either as a tertiary star in the system or as a nearby member in an open cluster. The third star should be less massive than the secondary star but by no more than few 0.01Mo. We estimate that the rate of CCSNIP is about 0.0001 times the rate of all CCSNe.
- [34] arXiv:2004.04461 [pdf, other]
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Title: Restoration of azimuthal symmetry of muon densities in extended air showersComments: Accepted for publication in Astroparticle PhysicsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)
At ground level, the azimuthal distribution of muons in inclined Extensive Air Showers (EAS) is asymmetric, mainly due to geometric effects. Several EAS observables sensitive to the primary particle mass, are constructed after mapping the density of secondary particles from the ground plane to the shower plane (perpendicular to the shower axis). A simple orthogonal projection of the muon coordinates onto this plane distorts the azimuthal symmetry in the shower plane. Using CORSIKA simulations, we correct for this distortion by projecting each muon onto the normal plane following its incoming direction, taking also into account the attenuation probability. We show that besides restoring the azimuthal symmetry of muons density around the shower axis, the application of this procedure has a significant impact on the reconstruction of the distribution of the muon production depth and of its maximum, $X_{\rm max}^{\mu}$, which is an EAS observable sensitive to the primary particle mass. Our results qualitatively suggest that not including it in the reconstruction process of $X_{\rm max}^{\mu}$ may introduce a bias in the results obtained by analyzing the actual data on the basis of Monte Carlo simulations.
- [35] arXiv:2004.04516 [pdf, other]
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Title: High Energy emission from Crab NebulaAuthors: Beka TevdorashviliSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Flaring episodes from Crab Nebula have been observed. A new mechanism of emission is explored. Particles in Crab pulsar are accelerated to multiple Tev energies, by some mechanisms, described in the paper and they are the reason of observed emission. We argue, that after accelerating to high energies, they may maintain the force-free regime - moving along the magnetic field lines in such a way that no force acts on them. This way, they can move to the Nebula without loss, which makes Tev energy emission from Crab Nebula quite possible.
- [36] arXiv:2004.04530 [pdf, ps, other]
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Title: On the ratios of \ion{Si}{4} lines ($λ$1394/$λ$1403) in an emerging flux regionComments: 22 pages, 17 figs, in press, ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The resonance lines of \ion{Si}{4} formed at $\lambda$1394 and 1403 {\AA} are the most critical for the diagnostics of the solar transition region in the observations of the Interface Region Imaging Spectrograph (IRIS). Studying the intensity ratios of these lines (1394{\AA}/1403{\AA}), which under optically thin condition is predicted to be two, helps us to diagnose the optical thickness of the plasma being observed. Here we study the evolution of the distribution of intensity ratios in 31 IRIS rasters recorded for four days during the emergence of an active region. We found that during the early phase of the development, the majority of the pixels show intensity ratios smaller than two. However, as the active region evolves, more and more pixels show the ratios closer to two. Besides, there are a substantial number of pixels with ratio values larger than 2. At the evolved stage of the active region, the pixels with ratios smaller than two were located on the periphery, whereas those with values larger than 2 were in the core. However, for quiet Sun regions, the obtained intensity ratios were close to two irrespective of the location on the disk. Our findings suggest that the \ion{Si}{4} lines observed in active regions are affected by the opacity during the early phase of the flux emergence. The results obtained here could have important implications for the modelling of the solar atmosphere, including the initial stage of the emergence of an active region as well as quiet Sun.
- [37] arXiv:2004.04531 [pdf, other]
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Title: Discovering Exotic AGN behind the Magellanic CloudsAuthors: Clara M. Pennock, Jacco Th. van Loon, Cameron Bell, Miroslav Filipović, Tana Joseph, Eleni VardoulakiComments: Proceedings paper of the IAU symposium "Nuclear Activity in Galaxies Across Cosmic Time" (Ethiopia) accepted to be published under the Cambridge University Press, eds. M. Povic, P. Marziani, J. Masegosa, H. Netzer, S. H. Negu, and S. B. TessemaSubjects: Astrophysics of Galaxies (astro-ph.GA)
The nearby Magellanic Clouds system covers more than 200 square degrees on the sky. Much of it has been mapped across the electromagnetic spectrum at high angular resolution and sensitivity X-ray (XMM-Newton), UV (UVIT), optical (SMASH), IR (VISTA, WISE, Spitzer, Herschel), radio (ATCA, ASKAP, MeerKAT). This provides us with an excellent dataset to explore the galaxy populations behind the stellar-rich Magellanic Clouds. We seek to identify and characterise AGN via machine learning algorithms on this exquisite data set. Our project focuses not on establishing sequences and distributions of common types of galaxies and active galactic nuclei (AGN), but seeks to identify extreme examples, building on the recent accidental discoveries of unique AGN behind the Magellanic Clouds.
- [38] arXiv:2004.04542 [pdf, other]
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Title: Chandra observations of the planetary nebula IC 4593Comments: 6 pages, 4 figures; Accepted to MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
The ACIS-S camera on board the Chandra X-ray Observatory has been used to discover a hot bubble in the planetary nebula (PN) IC4593, the most distant PN detected by Chandra so far. The data are used to study the distribution of the X-ray-emitting gas in IC 4593 and to estimate its physical properties. The hot bubble has a radius of ~2$^{\prime\prime}$ and is found to be confined inside the optically-bright innermost cavity of IC 4593. The X-ray emission is mostly consistent with that of an optically-thin plasma with temperature $kT\approx0.15$ keV (or $T_\mathrm{X}\approx1.7\times10^{6}$ K), electron density $n_\mathrm{e}\approx15$ cm$^{-3}$, and intrinsic X-ray luminosity in the 0.3-1.5 keV energy range $L_\mathrm{X}=3.4\times10^{30}$ erg s$^{-1}$. A careful analysis of the distribution of hard ($E>$0.8 keV) photons in IC 4593 suggests the presence of X-ray emission from a point source likely associated with its central star (CSPN). If this were the case, its estimated X-ray luminosity would be $L_\mathrm{X,CSPN}=7\times10^{29}$ erg s$^{-1}$, fulfilling the log$(L_\mathrm{X,CSPN}/L_\mathrm{bol})\approx-7$ relation for self-shocking winds in hot stars. The X-ray detection of the CSPN helps explain the presence of high-ionisation species detected in the UV spectra as predicted by stellar atmosphere models.
- [39] arXiv:2004.04547 [pdf, other]
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Title: Experimental Search for Dark Matter in ChinaSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex)
The nature of dark matter is one of the greatest mysteries in modern physics and astronomy. A wide variety of experiments have been carried out worldwide to search for the evidence of particle dark matter. Chinese physicists started experimental search for dark matter about ten years ago, and have produced results with high scientific impact. In this paper, we present an overview of the dark matter program in China, and discuss recent results and future directions.
- [40] arXiv:2004.04568 [pdf, other]
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Title: Fundamental effective temperature measurements for eclipsing binary stars I. Development of the method and application to AI PhoenicisComments: 12 pages, 10 figures, 6 tables; submitted to MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Stars with accurate and precise effective temperature (T$_{\rm eff}$) measurements are needed to test stellar atmosphere models and calibrate empirical methods to determine T$_{\rm eff}$. There are few standard stars currently available to calibrate temperature indicators for dwarf stars. Gaia parallaxes now make it possible, in principle, to measure T$_{\rm eff}$ for many dwarf stars in eclipsing binaries. We aim to develop a method that uses high-precision measurements of detached eclipsing binary stars, Gaia parallaxes and multi-wavelength photometry to obtain accurate and precise fundamental effective temperatures that can be used to establish a set of benchmark stars. We select the well-studied binary AI Phoenicis to test our method, since it has very precise absolute parameters and extensive archival photometry. The method uses the stellar radii and parallax for stars in eclipsing binaries. We use a Bayesian approach to obtain the integrated bolometric fluxes for the two stars from observed magnitudes, colours and flux ratios. The fundamental effective temperature of two stars in AI Phoenicis are $6193\pm24$ K for the F7V component and $5090\pm17$ K for the K0IV component. The zero-point error in the flux scale leads to a systematic error of only 0.2% ($\approx$ 11K) in T$_{\rm eff}$. We find that these results are robust against the details of the analysis, such as the choice of model spectra. Our method can be applied to eclipsing binary stars with radius, parallax and photometric measurements across a range of wavelengths. Stars with fundamental effective temperatures determined with this method can be used as benchmarks in future surveys.
- [41] arXiv:2004.04587 [pdf]
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Title: Radar evidence of subglacial liquid water on MarsAuthors: R. Orosei, S. E. Lauro, E. Pettinelli, A. Cicchetti, M. Coradini, B. Cosciotti, F. Di Paolo, E. Flamini, E. Mattei, M. Pajola, F. Soldovieri, M. Cartacci, F. Cassenti, A. Frigeri, S. Giuppi, R. Martufi, A. Masdea, G. Mitri, C. Nenna, R. Noschese, M. Restano, R. SeuComments: 27 pages, 10 figuresJournal-ref: Science 361, 490 (2018)Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
The presence of liquid water at the base of the Martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the Mars Advanced Radar for Subsurface and Ionosphere Sounding, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015, contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections were found within a well-defined, 20km wide zone centered at 193{\deg}E, 81{\deg}S, surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high dielectric permittivity >15, matching water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.
- [42] arXiv:2004.04590 [pdf, other]
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Title: Dust Settling Instability in Protoplanetary DiscsComments: 15 pages, 9 figures. Submitted to MNRAS. Comments are welcomeSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
The streaming instability (SI) has been extensively studied in the linear and non-linear regimes as a mechanism to concentrate solids and trigger planetesimal formation in the midplane of protoplanetary discs. A related dust settling instability (DSI) applies to particles while settling towards the midplane. The DSI has previously been studied in the linear regime, with predictions that it could trigger particle clumping away from the midplane. This work presents a range of linear calculations and non-linear simulations, performed with FARGO3D, to assess conditions for DSI growth. We expand on previous linear analyses by including particle size distributions and performing a detailed study of the amount of background turbulence needed to stabilize the DSI. When including binned size distributions, the DSI often produces converged growth rates with fewer bins than the standard SI. With background turbulence, we find that the most favorable conditions for DSI growth are weak turbulence, characterized by $\alpha \lesssim 10^{-6}$ with intermediate-sized grains that settle from one gas scale-height. These conditions could arise during a sudden decrease in disc turbulence following an accretion outburst. Ignoring background turbulence, we performed a parameter survey of local 2D DSI simulations. Particle clumping was either weak or occurred slower than particles settle. Clumping was reduced by a factor of two in a comparison 3D simulation. Overall, our results strongly disfavor the hypothesis that the DSI significantly promotes planetesimal formation. Non-linear simulations of the DSI with different numerical methods could support or challenge these findings.
- [43] arXiv:2004.04600 [pdf, ps, other]
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Title: No Radio Bursts Detected from FIRST J141918.9+394036 in Green Bank Telescope ObservationsAuthors: Kenzie Nimmo, Vishal Gajjar, Jason W. T. Hessels, Casey J. Law, Ryan S. Lynch, Andrew D. Seymour, Laura G. SpitlerComments: Accepted for publication in RNAASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
FRB 121102, the first-known repeating fast radio burst (FRB) source, is associated with a dwarf host galaxy and compact, persistent radio source. In an effort to find other repeating FRBs, FIRST J141918.9+394036 (hereafter FIRST J1419+3940) was identified in a search for similar persistent radio sources in dwarf host galaxies. FIRST J1419+3940 was subsequently identified as a radio transient decaying on timescales of decades, and it has been argued that it is the orphan afterglow of a long gamma-ray burst. FIRST J1419+3940 and FRB 121102's persistent radio source show observational similarities, though the latter appears to be stable in brightness. Nonetheless, if they have similar physical origins, then FIRST J1419+3940 may also contain a source capable of producing fast radio bursts. We report the non-detection of short-duration radio bursts from FIRST J1419+3940 during 3.1 h of observations with the 110-m Green Bank Telescope at both 2 and 6 GHz. FIRST J1419+3940 is 11 times closer compared with FRB 121102, and exhibits an optically-thin synchrotron spectrum above 1.4GHz; our search was thus sensitive to bursts more than 100 times weaker than those seen from FRB 121102. We encourage future burst searches to constrain the possible presence of an FRB-emitting source. Although such searches are high-risk, any such detection could greatly elucidate the origins of the FRB phenomenon.
- [44] arXiv:2004.04601 [pdf, other]
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Title: Parkes transient events: I. Database of single pulses, initial results and missing FRBsAuthors: S.-B. Zhang, G. Hobbs, C. J. Russell, L. Toomey, S. Dai, J. Dempsey, R. N. Manchester, S. Johnston, L. Staveley-Smith, X.-F. Wu, D. Li, Y.-Y. Yang, S.-Q. Wang, H. Qiu, R. Luo, C. Wang, C. Zhang, L. Zhang, R. MandowComments: 15 pages, 4 Figures, 6 Tables, 2 Appendix, accepted for publication in ApJSSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Phenomenology (hep-ph)
A large number of observations from the Parkes 64\,m-diameter radio telescope, recorded with high time resolution, are publicly available. We have re-processed all of the observations obtained during the first four years (from 1997 to 2001) of the Parkes Multibeam receiver system in order to identify transient events and have built a database that records the 568,736,756 pulse candidates generated during this search. We have discovered a new fast radio burst (FRB), FRB~010305, with a dispersion measure of 350$\pm$5\,\,cm$^{-3}\,$pc and explored why so few FRBs have been discovered in data prior to 2001. After accounting for the dispersion smearing across the channel bandwidth and the sky regions surveyed, the number of FRBs is found to be consistent with model predictions. We also present five single pulse candidates from unknown sources, but with Galactic dispersion measures. We extract a diverse range of sources from the database, which can be used, for example, as a training set of data for new software being developed to search for FRBs in the presence of radio frequency interference.
- [45] arXiv:2004.04615 [pdf, other]
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Title: Cross-Matching of OGLE III and GAIA catalogues: Investigation of Dark-lens microlensing candidatesComments: 8 pages, 6 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)
In this work, we use $13$ microlensing candidates with dark lenses from OGLE III catalogue \citep{2016MNRAS.458.3012W} and cross-match them with GAIA catalogue. We identify the microlensing source stars in GAIA catalogue by comparing the coordinate and the magnitude of stars and use the proper motion and the parallax parameters of the source stars. Combining with the microlensing light curves as well as microlensing parallax effect, we determine the mass and the distance of lenses from Earth. We conclude that the lens of some of microlensing events can be a blackhole.
- [46] arXiv:2004.04701 [pdf, ps, other]
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Title: Young Stellar Complexes in the Giant Galaxy UGC 11973Comments: Slightly edited version of the paper published in the Astronomy Reports, 2020, V.64, p.375. 9 pages, 3 figures, 3 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present results of the analysis of photometric and spectroscopic observations of the young stellar complexes in the late giant spiral galaxy UGC 11973. Photometric analysis in the UBVRI bands have been carried out for the 13 largest complexes. For one of them, metallicity of the surrounding gas Z = 0.013+-0.005, the mass M = (4.6+-1.6)*10^6 Msun, and the age of the stellar complex t = (2.0+-1.1)*10^6 yr were evaluated, using spectroscopic data. It is shown that all complexes are massive (M >= 1.7*10^5 Msun) stellar groups younger than 3*10^8 yr.
- [47] arXiv:2004.04702 [pdf, other]
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Title: Cosmology with the Wide-Field Infrared Survey Telescope -- Synergies with the Rubin Observatory Legacy Survey of Space and TimeAuthors: Tim Eifler, Melanie Simet, Elisabeth Krause, Christopher Hirata, Hung-Jin Huang, Xiao Fang, Vivian Miranda, Rachel Mandelbaum, Cyrille Doux, Chen Heinrich, Eric Huff, Hironao Miyatake, Shoubaneh Hemmati, Jiachuan Xu, Paul Rogozenski, Peter Capak, Ami Choi, Olivier Dore, Bhuvnesh Jain, Mike Jarvis, Niall MacCrann, Dan Masters, Eduardo Rozo, David N. Spergel, Michael Troxel, Anja von der Linden, Yun Wang, David H. Weinberg, Lukas Wenzl, Hao-Yi WuComments: comments welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We explore synergies between the space-based Wide-Field Infrared Survey Telescope (WFIRST) and the ground-based Rubin Observatory Legacy Survey of Space and Time (LSST). In particular, we consider a scenario where the currently envisioned survey strategy for WFIRST's High Latitude Survey (HLS), i.e., 2000 square degrees in four narrow photometric bands is altered in favor of a strategy that combines rapid coverage of the LSST area (to full LSST depth) in one band. We find that a 5-month WFIRST survey in the W-band can cover the full LSST survey area providing high-resolution imaging for >95% of the LSST Year 10 gold galaxy sample. We explore a second, more ambitious scenario where WFIRST spends 1.5 years covering the LSST area. For this second scenario we quantify the constraining power on dark energy equation of state parameters from a joint weak lensing and galaxy clustering analysis, and compare it to an LSST-only survey and to the Reference WFIRST HLS survey. Our survey simulations are based on the WFIRST exposure time calculator and redshift distributions from the CANDELS catalog. Our statistical uncertainties account for higher-order correlations of the density field, and we include a wide range of systematic effects, such as uncertainties in shape and redshift measurements, and modeling uncertainties of astrophysical systematics, such as galaxy bias, intrinsic galaxy alignment, and baryonic physics. Assuming the 5-month WFIRST wide scenario, we find a significant increase in constraining power for the joint LSST+WFIRST wide survey compared to LSST Y10 (FoM(Wwide)= 2.4 FoM(LSST)) and compared to LSST+WFIRST HLS (FoM(Wwide})= 5.5 FoM(HLS)).
- [48] arXiv:2004.04708 [pdf, other]
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Title: Science orbits in the Saturn-Enceladus circular restricted three-body problem with oblate primariesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Dynamical Systems (math.DS)
This contribution investigates the properties of a category of orbits around Enceladus. The motivation is the interest in the in situ exploration of this moon following the detection on behalf of Cassini of plumes of water and organic compounds close to its south pole. In a previous investigation, a set of heteroclinic transfers were designed between Halo orbits around the equilibrium points L1 and L2 of the circular restricted three-body problem with Saturn and Enceladus as primaries. The kinematical and geometrical characteristics of those trajectories makes them good candidates as science orbits for the extended observation of the surface of Enceladus: they are highly inclined, they approach the moon and they are maneuver free. However, the low heights above the surface and the strong perturbing effect of Saturn impose a more careful look at their dynamics, in particular regarding the influence of the polar flattening of the primaries. Therefore, those solutions are here reconsidered by employing a dynamical model that includes the effect of the oblateness of Saturn and Enceladus, individually and in combination. Substitutes of the Halo orbits around the equilibrium points L1 and L2 and their stable and unstable hyperbolic invariant manifolds are obtained in the perturbed models, and maneuver-free heteroclinic transfers are identified in the new framework. A systematic comparison with the corresponding solutions of the unperturbed problem shows that qualitative and quantitative features are not significantly altered when the oblateness of the primaries is taken into account, and that J2 of Saturn plays a larger role than the oblateness of Enceladus. From a mission perspective, the results confirm the scientific value of the solutions obtained in the classical circular restricted three-body problem and suggests that this simpler model can be used in a preliminary feasibility analysis.
Cross-lists for Fri, 10 Apr 20
- [49] arXiv:2004.02935 (cross-list from gr-qc) [pdf, ps, other]
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Title: Kinematical and dynamical aspects of ghost-matter cosmologiesComments: 14 pages, no figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We consider the kinematical and dynamical evolution of Friedmann universes with a mixture of non-interacting matter and a ghost-like field. Assuming that the conventional matter dominates today, we find that the ghost component can bring the future expansion and the past contraction of the model to a finite halt. Moreover, at the moment the expansion or contraction stops, the tendency of the universe is to bounce back and re-collapse or re-expand. Therefore, the presence of a (never dominant) ghost-field with negative density could drive the universe into an eternal cycle of finite expansion, collapse, and re-expansion. Our study outlines the key features of such a scenario and provides a simple condition for it to occur. We also investigate the linear stability of ghost-like Friedmann models. Employing dynamical-system techniques, we identify two families of fixed points, with and without spatial curvature respectively. The members of the first family correspond to coasting universes and are stable in the Lyapunov sense. Those of the latter family are unstable repellers when their matter satisfies the strong energy condition and Lyapunov stable in the opposite case.
- [50] arXiv:2004.04266 (cross-list from physics.ins-det) [pdf, other]
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Title: Interplay between phonon downconversion efficiency, density of states at Fermi energy, and intrinsic energy resolution for microwave kinectic inductance detectorsAuthors: Israel Hernandez, Gustavo Cancelo, Juan Estrada, Humberto Gonzalez, Andrew Lathrop, Martin Makler, Chris StoughtoSubjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Microwave Kinetic Inductance detectors (MKIDs) have been recognized as a powerful new tool for single photon detection. These highly multiplexed superconducting devices give timing and energy measurement for every detected photon. However, the full potential of MKID single photon spectroscopy has not been reached , the achieved energy resolution is lower than expected from first principles. Here, we study the efficiency in the phonon downconversion process following the absorption of energetic photons in MKIDs. Assuming previously published material properties, we measure an average downconversion efficiency for three TiN resonators is $\eta$=0.14. We discuss how this efficiency can impact the intrinsic energy resolution of MKID, and how any uncertainty in the unknown density of electron states at the Fermi energy directly affects the efficiency estimations.
- [51] arXiv:2004.04304 (cross-list from hep-ph) [pdf, other]
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Title: Cosmic-Ray Signatures of Dark Matter from a Flavor Dependent Gauge Symmetry Model with Neutrino Mass MechanismSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
We propose an extension to the Standard Model accommodating two families of Dirac neutral fermions and Majorana fermions under additional ${U(1)_{e-\mu} \times Z_3\times Z_2}$ symmetries where ${U(1)_{e-\mu}}$ is a flavor dependent gauge symmetry related to the first and second family of the lepton sector, which features a two-loop induced neutrino mass model. The two families are favored by minimally reproducing the current neutrino oscillation data and two mass difference squares and canceling the gauge anomalies at the same time. As a result, we have a prediction for neutrino masses. The lightest Dirac neutral fermion is a dark matter candidate with tree-level interaction restricted to electron, muon and neutrinos, which makes it difficult to detect in direct dark matter search as well as indirect search focusing on the ${\tau}$-channel, such as through ${\gamma}$-rays. It may however be probed by search for dark matter signatures in electron and positron cosmic rays, and allows interpretation of a structure appearing in the CALET electron+positron spectrum around 350-400 GeV as its signature, with a boost factor $\approx$40 Breit-Wigner enhancement of the annihilation cross section.
- [52] arXiv:2004.04350 (cross-list from hep-th) [pdf, other]
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Title: Gravitational Wave from Axion-SU(2) Gauge Fields: Effective Field Theory for Kinetically Driven InflationComments: 18 pages, 3 figuresSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
Building on Weinberg's approach to effective field theory for inflation, we construct an effective Lagrangian for a pseudo scalar (axion) inflaton field with shift symmetry. In this Lagrangian we allow the axion field to couple to non-Abelian gauge fields via a Chern-Simons term. We then analyze a class of inflation models driven by kinetic terms. We find that the observational constraints on the amplitudes of curvature perturbations and non-Gaussianity yield a lower bound for the tensor-to-scalar ratio of $r\gtrsim 5\times 10^{-3}$ from the vacuum fluctuation. The sourced gravitational wave from SU(2) gauge fields further increases the tensor-to-scalar ratio and makes the total gravitational wave partially chiral and non-Gaussian, which can be probed by polarization of the cosmic microwave background and direct detection experiments. We discuss constraints on parameter space due to backreaction of spin-2 particles produced by the gauge field.
- [53] arXiv:2004.04429 (cross-list from hep-th) [pdf, ps, other]
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Title: The Distribution of Vacua in Random Landscape PotentialsComments: 22 pages, 11 figuresSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Statistical Mechanics (cond-mat.stat-mech)
Landscape cosmology posits the existence of a convoluted, multidimensional, scalar potential -- the "landscape" -- with vast numbers of metastable minima. Random matrices and random functions in many dimensions provide toy models of the landscape, allowing the exploration of conceptual issues associated with these scenarios. We compute the relative number and slopes of minima as a function of the vacuum energy $\Lambda$ in an $N$-dimensional Gaussian random potential, quantifying the associated probability density, $p(\Lambda)$. After normalisations $p(\Lambda)$ depends only on the dimensionality $N$ and a single free parameter $\gamma$, which is related to the power spectrum of the random function. For a Gaussian landscape with a Gaussian power spectrum, the fraction of positive minima shrinks super-exponentially with $N$; at $N=100$, $p(\Lambda>0) \approx 10^{-780}$. Likewise, typical eigenvalues of the Hessian matrices reveal that the flattest approaches to typical minima grow flatter with $N$, while the ratio of the slopes of the two flattest directions grows with $N$. We discuss the implications of these results for both swampland and conventional anthropic constraints on landscape cosmologies. In particular, for parameter values when positive minima are extremely rare, the flattest approaches to minima where $\Lambda \approx 0$ are much flatter than for typical minima, increasingly the viability of quintessence solutions.
- [54] arXiv:2004.04506 (cross-list from gr-qc) [pdf, ps, other]
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Title: Crossing the Big Bang singularityAuthors: C. WetterichComments: 10 pagesSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
A simple model for a scalar field and gravity admits cosmological solutions which cross the Big Bang singularity. In the scaling frame with field dependent effective Planck mass these solutions are regular. They become singular in the Einstein frame with fixed Planck mass. This field singularity arises since the field transformation of the metric to the Einstein frame is singular at the crossing point of a vanishing scalar field. No physical singularity is present . Within general models with no more than two derivatives we find that a crossing of the "Big Bang singularity" is not generic. It needs a tuning of model parameters.
- [55] arXiv:2004.04527 (cross-list from gr-qc) [pdf, other]
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Title: Numerical solutions for phase noise due to pointing jitter with the LISA telescopeAuthors: Jean-Yves Vinet, Nelson Christensen, Nicoleta Dinu-Jaeger, Michel Lintz, Nary Man, Mikhaël PichotJournal-ref: Jean-Yves Vinet et al 2020 J. Phys. Commun. 4 045005Subjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM); Optics (physics.optics)
The aim of the Laser Interferometer Space Antenna (LISA) is to detect gravitational waves through a phase modulation in long (2.5 Mkm) laser light links between spacecraft. Among other noise sources to be addressed are the phase fluctuations caused by a possible angular jitter of the emitted beam. The present paper follows our preceding one (Vinet et al 2019 Class. Quant. Grav. 36, 205 003) based on an analytical study of the far field phase. We address here a numerical treatment of the phase, to first order in the emitted wavefront aberrations, but without any assumptions on the static bias term. We verify that, in the phase change, the higher order terms in the static mispointing are consistent with the results found in our preceding paper.
- [56] arXiv:2004.04540 (cross-list from physics.class-ph) [pdf, ps, other]
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Title: On the electrostatic potential and electric field of a uniformly charged diskComments: 14 pages, 6 figures, to be published in European Journal of PhysicsSubjects: Classical Physics (physics.class-ph); Astrophysics of Galaxies (astro-ph.GA)
We calculate the electrostatic potential and electric field of a uniformly charged disk everywhere in space. This electrostatic problem was solved long ago, and its gravitational analogue - even earlier. However, it seems that physics students are not aware of the solution, because it is not presented in textbooks. The purpose of the present article is to fill this gap in the pedagogical literature.
Replacements for Fri, 10 Apr 20
- [57] arXiv:1810.05051 (replaced) [pdf, other]
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Title: Interpreting measurements of the anisotropic galaxy power spectrumSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
- [58] arXiv:1812.03490 (replaced) [pdf, other]
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Title: Modelling the SPARC galaxies using a neo-MOND formalism, and the determination of distance scales and masses purely from disc dynamical dataAuthors: David RoscoeComments: 32 pages; 4 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [59] arXiv:1902.07718 (replaced) [pdf, other]
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Title: BSE versus StarTrack: implementations of new wind, remnant-formation, and natal-kick schemes in NBODY7 and their astrophysical consequencesAuthors: Sambaran Banerjee, Krzysztof Belczynski, Christopher L. Fryer, Peter Berczik, Jarrod R. Hurley, Rainer Spurzem, Long WangComments: 27 pages, 15 figures, 2 tables. Accepted for publication in Astronomy and AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
- [60] arXiv:1905.05089 (replaced) [pdf, other]
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Title: Gamma-rays from kilonova: a potential probe of r-process nucleosynthesisAuthors: Oleg Korobkin, Aimee M. Hungerford, Christopher L. Fryer, Matthew R. Mumpower, G. Wendell Misch, Trevor M. Sprouse, Jonas Lippuner, Rebecca Surman, Aaron J. Couture, Peter F. Bloser, Farzane Shirazi, Wesley P. Even, W. Thomas Vestrand, Richard S. MillerComments: 14 pages, 11 figuresJournal-ref: The Astrophysical Journal, Volume 889, Issue 2, id.168, 2020Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [61] arXiv:1905.06086 (replaced) [pdf, other]
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Title: Coalescence Time of Compact Binary SystemsComments: 6 pages, 1 figure, submitted. Revised calculation in the first post-Newtonian approximationsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [62] arXiv:1906.10185 (replaced) [pdf, other]
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Title: Dark matter mass from relic abundance, an extra $U(1)$ gauge boson, and active-sterile neutrino mixingComments: 24 pages, 6 figures, To be published in Physical Review DSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
- [63] arXiv:1907.05533 (replaced) [pdf, other]
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Title: Neutrinos from Type Ia and failed core-collapse supernovae at dark matter detectorsAuthors: Nirmal RajComments: 4 pages revtex4 + references, 2 figures; v2: minor changes, references added, matches PRL versionSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)
- [64] arXiv:1907.10633 (replaced) [pdf, other]
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Title: Impact of the collision model on the multi-messenger emission from Gamma-Ray Burst internal shocksComments: 18 pages, 10 figures; version accepted for ApJ; revised diskussion in section 6Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [65] arXiv:1909.05274 (replaced) [pdf, other]
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Title: An Extension of the Athena++ Framework for General Equations of StateAuthors: Matthew S. B. ColemanComments: 32 pages, 12 figures, 18 tables, accepted by ApJSSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Computational Physics (physics.comp-ph); Fluid Dynamics (physics.flu-dyn)
- [66] arXiv:1909.05320 (replaced) [pdf, other]
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Title: DAMA/LIBRA annual modulation and Axion Quark Nugget Dark Matter ModelAuthors: Ariel ZhitnitskyComments: matches the published version (Phys Rev D). added: new refs and Section VD on search for the correlations between the DL signals and the signatures from infrasonic or seismic events using such instruments as Distributed Acoustic SensingSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex)
- [67] arXiv:1912.02131 (replaced) [pdf, other]
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Title: Linearly forced fluid flow on a rotating sphereComments: 13 pages, 6 figuresJournal-ref: J. Fluid Mech. 892 (2020) A30Subjects: Fluid Dynamics (physics.flu-dyn); Earth and Planetary Astrophysics (astro-ph.EP); Soft Condensed Matter (cond-mat.soft)
- [68] arXiv:2001.02617 (replaced) [pdf, other]
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Title: Lack of Debye and Meissner screening in strongly magnetized quark matter at intermediate densitiesComments: 18 pages, 5 figuresJournal-ref: Phys. Rev. D 101, 056012 (2020)Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
- [69] arXiv:2001.02701 (replaced) [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. Accepted by A&ASubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [70] arXiv:2001.02973 (replaced) [pdf, ps, other]
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Title: Examining the secondary product origin of cosmic ray positrons with the latest AMS-02 dataComments: Accepted by ApJ, 5 pages, 2 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [71] arXiv:2001.10135 (replaced) [pdf, ps, other]
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Title: Tracing the high energy theory of gravity: an introduction to Palatini inflationAuthors: Tommi TenkanenComments: 24 pages, no figures. Matches the version published in General Relativity and GravitationSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
- [72] arXiv:2001.11505 (replaced) [pdf, other]
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Title: A little theory of everything, with heavy neutral leptonsComments: 34 pages, 7 figures; v2. improved version with discussion of DM indirect detection, additional HNL decay channels, references addedSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [73] arXiv:2002.02027 (replaced) [pdf, other]
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Title: Does Nature use neutral beams for interstellar plasma heating around compact objects?Comments: MNRAS, acceptedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [74] arXiv:2002.07644 (replaced) [pdf, other]
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Title: A direct approach to realising quantum filters for high-precision measurementsSubjects: Quantum Physics (quant-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [75] arXiv:2002.08636 (replaced) [pdf, other]
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Title: Screening corrections to Electron Capture Rates and resulting constraints on Primordial Magnetic FieldsComments: 18 pages, 7 figures, submitted to Phys. ReV. DJournal-ref: Phys. Rev. D. Vol 101, 083010 (2020)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Plasma Physics (physics.plasm-ph)
- [76] arXiv:2002.11975 (replaced) [pdf, ps, other]
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Title: Magnetars from Neutron Star--White Dwarf Mergers: Application to Fast Radio BurstsComments: Published in ApJ on 8 April 2020Journal-ref: 2020ApJ...893...9ZSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [77] arXiv:2002.12383 (replaced) [pdf, other]
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Title: The study of the angular and spatial distribution of radio selected AGNs and star-forming galaxies in the ELAIS N1 fieldComments: There are 13 pages, 10 figures and 3 tables. The paper is accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [78] arXiv:2003.07355 (replaced) [pdf, other]
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Title: Early Dark Energy Does Not Restore Cosmological ConcordanceComments: 36 pages, 23 figures. CLASS_EDE code publicly available at this https URLSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
- [79] arXiv:2003.07409 (replaced) [pdf, other]
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Title: Fingerprints of binary black hole formation channels encoded in the mass and spin of merger remnantsComments: 25 pages, 13 figures, 2 tables. Accepted for publication in the ApJSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [80] arXiv:2003.08387 (replaced) [pdf, other]
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Title: Interacting radiation after Planck and its implications for the Hubble TensionComments: 21 pages, 8 figures; v2: new section to discuss implication to models (+2 figures), fixed discussion on neutrino-scalar interactions, references added, conclusions unchangedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
- [81] arXiv:2003.11106 (replaced) [pdf, other]
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Title: Orbital Parameter Determination for Wide Stellar Binary Systems in the Age of GaiaAuthors: Logan A. Pearce, Adam L. Kraus, Trent J. Dupuy, Andrew W. Mann, Elisabeth R. Newton, Benjamin N. Tofflemire, Andrew VanderburgComments: 18 pages, 10 figures, accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [82] arXiv:2003.12722 (replaced) [pdf, other]
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Title: Power and spatial complexity in stochastic reconnectionSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)
- [83] arXiv:2003.13696 (replaced) [pdf, other]
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Title: Cosmological Dark Matter: a Review (the April Fool Edition)Authors: M. R. Lovell (University of Iceland)Comments: 3 pages, 4 figures. Contact: lovell@hi.isSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
- [84] arXiv:2004.00519 (replaced) [pdf, other]
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Title: Chemical equilibrium in AGB atmospheres: Successes, failures, and prospects for small molecules, clusters, and condensatesComments: Accepted for publication in A&A. Abstract abridged. English edited with respect to previous versionSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
- [85] arXiv:2004.00610 (replaced) [pdf, other]
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Title: Update on Coupled Dark Energy and the $H_0$ tensionComments: 15 pages, 3 tables, and 4 figures. Comments, one more table and appendix C addedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [86] arXiv:2004.00902 (replaced) [pdf, other]
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Title: The Gravitational Wave Emission of Double White Dwarf CoalescencesComments: 10 pages, 5 figures, accepted by RAA. Reference added in Section 6. References updated to match the accepted version on RAASubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
- [87] arXiv:2004.00947 (replaced) [pdf, other]
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Title: Model-independent constraints in inflationary magnetogenesisComments: 16 pages, 2 figures, corrected typos and the secondary estimate, a reference added; corrected errors made in arXiv:1902.05894 and arXiv:1911.10424Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
- [88] arXiv:2004.01042 (replaced) [pdf, ps, other]
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Title: Threshold of Primordial Black Hole Formation in Nonspherical CollapseComments: Two-column, 5 pages, 8 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [89] arXiv:2004.01197 (replaced) [pdf, other]
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Title: Fundamental differences in the radio properties of red and blue quasars: enhanced compact AGN emission in red quasarsAuthors: V. A. Fawcett, D. M. Alexander, D. J. Rosario, L. Klindt (CEA, Durham University), S. Fotopoulou (University of Bristol), E. Lusso (University of Florence, INAF-Arcetri), L. K. Morabito (CEA, Durham University), G. Calistro Rivera (ESO)Comments: 17 pages, 17 Figures. Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [90] arXiv:2004.01308 (replaced) [pdf, other]
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Title: A flare in the optical spotted in the changing-look Seyfert NGC 3516Authors: D. Ilic, V. Oknyansky, L.C. Popovic, S.S. Tsygankov, A.A. Belinski, A.M. Tatarnikov, A.V. Dodin, N.I. Shatsky, N.P. Ikonnikova, N. Rakic, A. Kovacevic, S. Marceta-Mandic, M.A. Burlak, E.O. Mishin, N.V. Metlova, S.A. Potanin, S.G. ZheltoukhovComments: 7 pages, 6 figures, accepted in A&A (corrected after receiving comments from the language editor)Subjects: Astrophysics of Galaxies (astro-ph.GA)
- [91] arXiv:2004.03987 (replaced) [pdf, other]
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Title: A new fitting function for GRB MeV spectra based on the internal shock synchrotron modelComments: Accepted for publication in Astronomy and AstrophysicsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
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