Astrophysics
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New submissions for Wed, 4 Dec 19
- [1] arXiv:1912.01002 [pdf]
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Title: Angular momentum bounds in particle systemsAuthors: Daniel PfennigerComments: This article published as part of the topical collection on 50 years of Celestial Mechanics and Dynamical Astronomy. The abstract references in the publised version have been altered by the publisherJournal-ref: Celestial Mechanics and Dynamical Astronomy, December 2019, 131:58Subjects: Astrophysics of Galaxies (astro-ph.GA); Mathematical Physics (math-ph)
Four expressions involving sums of position and velocity coordinates bounding the total angular momentum of particle systems, and by extension of any continuous or discontinuous material systems, are derived which are tighter for any particle configuration than similar inequalities derived by Sundman (1913), Saari (2005) and Scheeres (2012). Eight distinct inequalities can thus be ordered according to their tightness to angular momentum.
- [2] arXiv:1912.01004 [pdf, other]
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Title: Magnetic Inflation and Stellar Mass. V. Intensification and saturation of M dwarf absorption lines with Rossby numberAuthors: Philip S. Muirhead, Mark J. Veyette, Elisabeth R. Newton, Christopher A. Theissen, Andrew W. MannComments: Accepted to AJ. Machine readable tables in the source files. Reduced spectra will be available in the published versionSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
In young sun-like stars and field M dwarf stars, chromospheric and coronal magnetic activity indicators such as H$\alpha$, X-ray and radio emission are known to saturate with low Rossby number ($Ro \lesssim 0.1$), defined as the ratio of rotation period to convective turnover time. The mechanism for the saturation is unclear. In this paper, we use photospheric Ti I and Ca I absorption lines in $Y$ band to investigate magnetic field strength in M dwarfs for Rossby numbers between 0.01 and 1.0. The equivalent widths of the lines are magnetically enhanced by photospheric spots, a global field or a combination of the two. The equivalent widths behave qualitatively similar to the chromospheric and coronal indicators: we see increasing equivalent widths (increasing absorption) with decreasing $Ro$ and saturation of the equivalent widths for $Ro \lesssim 0.1$. The majority of M dwarfs in this study are fully convective. The results add to mounting evidence that the magnetic saturation mechanism occurs at or beneath the stellar photosphere.
- [3] arXiv:1912.01005 [pdf, other]
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Title: AVIATOR: Morphological object reconstruction in 3D. An application to dense coresComments: 11 pages, 16 figures, accepted for publication by Astronomy & Astrophysics. The AVIATOR code and a Jupyter notebook illustrating its use is publicly available at this https URLSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)
Reconstructing 3D distributions from their 2D projections is a ubiquitous problem in various scientific fields, particularly so in observational astronomy. In this work, we present a new approach to solving this problem: a Vienna inverse-Abel-transform based object reconstruction algorithm AVIATOR. The reconstruction that it performs is based on the assumption that the distribution along the line of sight is similar to the distribution in the plane of projection, which requires a morphological analysis of the structures in the projected image. The output of the AVIATOR algorithm is an estimate of the 3D distribution in the form of a reconstruction volume that is calculated without the problematic requirements that commonly occur in other reconstruction methods such as symmetry in the plane of projection or modelling of radial profiles. We demonstrate the robustness of the technique to different geometries, density profiles, and noise by applying the AVIATOR algorithm to several model objects. In addition, the algorithm is applied to real data: We reconstruct the density and temperature distributions of two dense molecular cloud cores and find that they are in excellent agreement with profiles reported in the literature. The AVIATOR algorithm is thus capable of reconstructing 3D distributions of physical quantities consistently using an intuitive set of assumptions.
- [4] arXiv:1912.01009 [pdf, other]
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Title: Evidence for a Dichotomy in the Interior Structures of Jupiter and Saturn from Helium Phase SeparationComments: Submitted to ApJ, revised in response to referee commentsSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We examine the comparative thermal evolution of Jupiter and Saturn applying recent theoretical results for helium's immiscibility in fluid metallic hydrogen. The redistribution of helium in their interiors proceeds very differently for the two planets. We confirm that based on Jupiter's atmospheric helium depletion as observed in situ by the Galileo entry probe, Jupiter's interior helium has differentiated modestly, and we present models reconciling Jupiter's helium depletion, radius, and heat flow at the solar age. Jupiter's recently revised Bond albedo implies a lower intrinsic flux for the planet, accommodating more luminosity from helium differentiation such that mildly superadiabatic interiors can satisfy all constraints. The same phase diagram applied to the less massive Saturn predicts dramatic helium differentiation to the degree that Saturn inevitably forms a helium-rich shell or core, an outcome previously proposed by Stevenson & Salpeter and others. The luminosity from Saturn's helium differentiation is sufficient to extend its cooling time to the solar age, even for adiabatic interiors. This model predicts Saturn's atmospheric helium to be depleted to Y=0.07+/-0.01, corresponding to a He/H_2 mixing ratio 0.036+/-0.006. We also show that neon differentiation may have contributed to both planets' luminosity in the past. These results demonstrate that Jupiter and Saturn's thermal evolution can be explained self-consistently with a single physical model, and have important implications for future models of Saturn's internal structure and dynamo.
- [5] arXiv:1912.01010 [pdf, other]
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Title: Computing the Small-Scale Galaxy Power Spectrum and Bispectrum in Configuration-SpaceComments: 29 pages, 14 figures, accepted by MNRAS. Code is available at this https URL with documentation at this https URLSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We present a new class of estimators for computing small-scale power spectra and bispectra in configuration-space via weighted pair- and triple-counts, with no explicit use of Fourier transforms. Particle counts are truncated at $R_0\sim 100h^{-1}\,\mathrm{Mpc}$ via a continuous window function, which has negligible effect on the measured power spectrum multipoles at small scales. This gives a power spectrum algorithm with complexity $\mathcal{O}(NnR_0^3)$ (or $\mathcal{O}(Nn^2R_0^6)$ for the bispectrum), measuring $N$ galaxies with number density $n$. Our estimators are corrected for the survey geometry and have neither self-count contributions nor discretization artifacts, making them ideal for high-$k$ analysis. Unlike conventional Fourier transform based approaches, our algorithm becomes more efficient on small scales (since a smaller $R_0$ may be used), thus we may efficiently estimate spectra across $k$-space by coupling this method with standard techniques. We demonstrate the utility of the publicly available power spectrum algorithm by applying it to BOSS DR12 simulations to compute the high-$k$ power spectrum and its covariance. In addition, we derive a theoretical rescaled-Gaussian covariance matrix, which incorporates the survey geometry and is found to be in good agreement with that from mocks. Computing configuration- and Fourier-space statistics in the same manner allows us to consider joint analyses, which can place stronger bounds on cosmological parameters; to this end we also discuss the cross-covariance between the two-point correlation function and the small-scale power spectrum.
- [6] arXiv:1912.01011 [pdf, other]
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Title: GEOMAX: beyond linear compression for 3pt galaxy clustering statisticsComments: 17 pages, 9 figures, submitted to MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We present the GEOMAX algorithm and its Python implementation for a two-step compression of bispectrum measurements. The first step groups bispectra by the geometric properties of their arguments; the second step then maximises the Fisher information with respect to a chosen set of model parameters in each group. The algorithm only requires the derivatives of the data vector with respect to the parameters and a small number of mock data, producing an effective, non-linear compression. By applying GEOMAX to bispectrum monopole measurements from BOSS DR12 CMASS redshift-space galaxy clustering data, we reduce the $68\%$ credible intervals for the inferred parameters $\left(b_1,b_2,f,\sigma_8\right)$ by $\left(50.4\%,56.1\%,33.2\%,38.3\%\right)$ with respect to standard MCMC on the full data vector. We run the analysis and comparison between compression methods over one hundred galaxy mocks to test the statistical significance of the improvements. On average GEOMAX performs $\sim15\%$ better than geometrical or maximal linear compression alone and is consistent with being lossless. Given its flexibility, the GEOMAX approach has the potential to optimally exploit three-point statistics of various cosmological probes like weak lensing or line-intensity maps from current and future cosmological data-sets such as DESI, Euclid, PFS and SKA.
- [7] arXiv:1912.01012 [pdf, ps, other]
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Title: Non-steady heating of cool cores of galaxy clusters by ubiquitous turbulence and AGNComments: 12 pages, 18 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
Recent cosmological simulations have shown that turbulence should be generally prevailing in clusters because clusters are continuously growing through matter accretion. Using hydrodynamic simulations, we study the heating of cool-core clusters by the ubiquitous turbulence as well as feedback from the central active galactic nuclei (AGNs). We find that the AGN shows intermittent activities in the presence of moderate turbulence similar to the one observed with Hitomi. The cluster core maintains a quasi-equilibrium state for most of the time because the heating through turbulent diffusion is nearly balanced with radiative cooling. The balance is gradually lost because of slight dominance of the radiative cooling, and the AGN is ignited by increased gas inflow. Finally, when the AGN bursts, the core is heated almost instantaneously. Thanks to the pre-existing turbulence, the heated gas is distributed throughout the core without triggering thermal instability and causing catastrophic cooling, and the core recovers the quasi-equilibrium state. The AGN bursts can be stronger in lower-mass clusters. Predictions of our model can be easily checked with future X-ray missions like XRISM and Athena.
- [8] arXiv:1912.01015 [pdf, other]
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Title: Nonequilibrium ionization and ambipolar diffusion in solar magnetic flux emergence processesComments: Accepted in A&A. 15 pages, 11 figures, 7 moviesSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Magnetic flux emergence has been shown to be a key mechanism for unleashing a wide variety of solar phenomena. However, there are still open questions concerning the rise of the magnetized plasma through the atmosphere, mainly in the chromosphere, where the plasma departs from local thermodynamic equilibrium (LTE) and is partially ionized. We aim to investigate the impact of the nonequilibrium (NEQ) ionization and recombination and molecule formation of hydrogen, as well as ambipolar diffusion, on the dynamics and thermodynamics of the flux emergence process. Using the Bifrost code, we performed 2.5D numerical experiments of magnetic flux emergence from the convection zone up to the corona. The experiments include the NEQ ionization and recombination of atomic hydrogen, the NEQ formation and dissociation of H2 molecules, and the ambipolar diffusion term of the Generalized Ohm's Law. Our experiments show that the LTE assumption substantially underestimates the ionization fraction in most of the emerged region, leading to an artificial increase in the ambipolar diffusion and, therefore, in the heating and temperatures as compared to those found when taking the NEQ effects on the hydrogen ion population into account. We see that LTE also overestimates the number density of H2 molecules within the emerged region, thus mistakenly magnifying the exothermic contribution of the H2 molecule formation to the thermal energy during the flux emergence process. We find that the ambipolar diffusion does not significantly affect the amount of total unsigned emerged magnetic flux, but it is important in the shocks that cross the emerged region, heating the plasma on characteristic times ranging from 0.1 to 100 s. We also briefly discuss the importance of including elements heavier than hydrogen in the equation of state so as not to overestimate the role of ambipolar diffusion in the atmosphere.
- [9] arXiv:1912.01017 [pdf, other]
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Title: KELT-25b and KELT-26b: A Hot Jupiter and a Substellar Companion Transiting Young A-stars Observed by TESSAuthors: Romy Rodríguez Martínez, B. Scott Gaudi, Joseph E. Rodriguez, George Zhou, Jonathan Labadie-Bartz, Samuel N. Quinn, Kaloyan Minev Penev, Thiam-Guan Tan, David W. Latham, Leonardo A. Paredes, John Kielkopf, Brett C. Addison, Duncan J. Wright, Johanna K. Teske, Steve B. Howell, David R. Ciardi, Carl Ziegler, Keivan G. Stassun, Marshall C. Johnson, Jason D. Eastman, Robert J. Siverd, Thomas G. Beatty, Luke G. Bouma, Joshua Pepper, Michael B. Lund, Steven Villanueva, Daniel J. Stevens, Eric L. N. Jensen, Coleman Kilby, David H. Cohen, Daniel Bayliss, Allyson Bieryla, Phillip A. Cargile, Karen A. Collins, Dennis M. Conti, Knicole D. Colon, Ivan A. Curtis, Darren L. DePoy, Phil A. Evans, Dax Feliz, Joao Gregorio, Jason Rothenberg, David J. James, Matthew T. Penny, Phillip A. Reed, Howard M. Relles, et al. (46 additional authors not shown)Comments: 24 pages, 18 figures, 8 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
We present the discoveries of KELT-25b (TIC 65412605, TOI-626.01) and KELT-26b (TIC 160708862, TOI-1337.01), two transiting companions orbiting relatively bright, early A-stars. The transit signals were initially detected by the KELT survey, and subsequently confirmed by \textit{TESS} photometry. KELT-25b is on a 4.40-day orbit around the V = 9.66 star CD-24 5016 ($T_{\rm eff} = 8280^{+440}_{-180}$ K, $M_{\star}$ = $2.18^{+0.12}_{-0.11}$ $M_{\odot}$), while KELT-26b is on a 3.34-day orbit around the V = 9.95 star HD 134004 ($T_{\rm eff}$ =$8640^{+500}_{-240}$ K, $M_{\star}$ = $1.93^{+0.14}_{-0.16}$ $M_{\odot}$), which is likely an Am star. We have confirmed the sub-stellar nature of both companions through detailed characterization of each system using ground-based and \textit{TESS} photometry, radial velocity measurements, Doppler Tomography, and high-resolution imaging. For KELT-25, we determine a companion radius of $R_{\rm P}$ = $1.64^{+0.039}_{-0.043}$ $R_{\rm J}$, and a 3-sigma upper limit on the companion's mass of $\sim64~M_{\rm J}$. For KELT-26b, we infer a planetary mass and radius of $M_{\rm P}$ = $1.41^{+0.43}_{-0.51}$ $M_{\rm J}$ and $R_{\rm P}$ = $1.940^{+0.060}_{-0.058}$ $R_{\rm J}$. From Doppler Tomographic observations, we find KELT-26b to reside in a highly misaligned orbit. This conclusion is weakly corroborated by a subtle asymmetry in the transit light curve from the \textit{TESS} data. KELT-25b appears to be in a well-aligned, prograde orbit, and the system is likely a member of a cluster or moving group.
- [10] arXiv:1912.01020 [pdf, other]
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Title: Do AGN really suppress star formation?Comments: IAU Proceedings No. 356 "Nuclear Activity in Galaxies Across Cosmic Time", M. Povic et alSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
Active galactic nuclei (AGN) are believed to regulate star formation inside their host galaxies through "AGN feedback". We summarise our on-going study of luminous AGN (z~0.2-3; L_(AGN,bol)>~10^43 erg/s), which is designed to search for observational signatures of feedback by combining observed star-formation rate (SFR) measurements from statistical samples with cosmological model predictions. Using the EAGLE hydrodynamical cosmological simulations, in combination with our Herschel+ALMA surveys, we show that - even in the presence of AGN feedback - we do not necessarily expect to see any relationships between average galaxy-wide SFRs and instantaneous AGN luminosities. We caution that the correlation with stellar mass for both SFR and AGN luminosity can contribute to apparent observed positive trends between these two quantities. On the other hand, the EAGLE simulations, which reproduce our observations, predict that a signature of AGN feedback can be seen in the wide specific SFR distributions of $all$ massive galaxies (not just AGN hosts). Overall, whilst we can not rule out that AGN have an immediate small-scale impact on in-situ star-formation, all of our results are consistent with a feedback model where galaxy-wide in-situ star formation is not rapidly suppressed by AGN, but where the feedback likely acts over a longer timescale than a single AGN episode.
- [11] arXiv:1912.01024 [pdf, other]
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Title: Toward the low-scatter selection of X-ray clusters: cluster detection by outskirts for eROSITAAuthors: Florian Käfer, Alexis Finoguenov, Dominique Eckert, Nicolas Clerc, Miriam E. Ramos-Ceja, Jeremy S. Sanders, Vittorio GhirardiniSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
One key ingredient in using galaxy clusters (GCs) as a precision cosmological probe in large X-ray surveys is to understand selection effects. The dependence of the X-ray emission on the square of the gas density leads to a predominant role of GC cool cores in the detection. The contribution of cool cores to the X-ray luminosity does not scale with GC mass and cosmology and therefore affects the use of X-ray GCs in producing cosmological constraints. One of the main science goals of the eROSITA mission is to constrain cosmology with a wide X-ray survey. We propose an eROSITA GC detection scheme that avoids the use of X-ray GC centers in detection. We calculate theoretical expectations and characterize the performance of this scheme by simulations. Performing realistic simulations of point sources (PSs) in survey mode we search for spatial scales where the extended signal is uncontaminated by the PS flux. We derive a combination of scales and thresholds, which result in a clean extended source catalog. We design the output of the GC detection which enables calibrating the core-excised luminosity using external mass measurements. We provide a way to incorporate the results of this calibration in the production of final core-excised luminosity. Similarly to other GC detection pipelines, we sample the flux - core radius detection space of our method and find many similarities with the pipeline used in the 400d survey. Both detection methods require large statistics on compact GCs, in order to reduce the contamination from PSs. The benefit of our pipeline consists in the sensitivity to the outer GC shapes, which are characterized by large core sizes with little GC to GC variation at a fixed total mass. Galaxy cluster detection by outskirts improves the GC characterization using eROSITA survey data and is expected to yield well characterized GC catalogs having simple selection functions.
- [12] arXiv:1912.01026 [pdf, other]
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Title: The CO(3-2)/CO(1-0) luminosity line ratio in nearby star-forming galaxies and AGN from xCOLD GASS, BASS and SLUGSAuthors: Isabella Lamperti, Amélie Saintonge, Michael Koss, Serena Viti, Christine D. Wilson, Hao He, T. Taro Shimizu, Thomas R. Greve, Richard Mushotzky, Ezequiel Treister, Carsten Kramer, David Sanders, Kevin Schawinski, Linda J. TacconiSubjects: Astrophysics of Galaxies (astro-ph.GA)
We study the r31=L'CO(3-2)/L'CO(1-0) luminosity line ratio in a sample of nearby (z < 0.05) galaxies: 25 star-forming galaxies (SFGs) from the xCOLD GASS survey, 36 hard X-ray selected AGN host galaxies from BASS and 37 infrared luminous galaxies from SLUGS. We find a trend for r31 to increase with star-formation efficiency (SFE). We model r31 using the UCL-PDR code and find that the gas density is the main parameter responsible for variation of r31, while the interstellar radiation field and cosmic ray ionization rate play only a minor role. We interpret these results to indicate a relation between SFE and gas density. We do not find a difference in the r31 value of SFGs and AGN host galaxies, when the galaxies are matched in SSFR (<r31>= 0.52 +/- 0.04 for SFGs and <r31> = 0.53 +/- 0.06 for AGN hosts). According to the results of UCL-PDR models, the X-rays can contribute to the enhancement of the CO line ratio, but only for strong X-ray fluxes and for high gas density (nH > 10$^4$ cm-3). We find a mild tightening of the Kennicutt-Schmidt relation when we use the molecular gas mass surface density traced by CO(3-2) (Pearson correlation coefficient R=0.83), instead of the molecular gas mass surface density traced by CO(1-0) (R=0.78), but the increase in correlation is not statistically significant (p-value=0.06). This suggests that the CO(3-2) line can be reliably used to study the relation between SFR and molecular gas for normal SFGs at high redshift, and to compare it with studies of low-redshift galaxies, as is common practice.
- [13] arXiv:1912.01028 [pdf, other]
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Title: Investigating the spectral age problem with powerful radio galaxiesAuthors: Vijay H. Mahatma, Martin J. Hardcastle, Judith H. Croston, Jeremy Harwood, Judith Ineson, Javier MoldonComments: accepted for publication in MNRAS. 20 pages, 15 figures, 8 tablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)
The 'spectral age problem' is our systematic inability to reconcile the maximum cooling time of radiating electrons in the lobes of a radio galaxy with its age as modelled by the dynamical evolution of the lobes. While there are known uncertainties in the models that produce both age estimates, `spectral' ages are commonly underestimated relative to dynamical ages, consequently leading to unreliable estimates of the time-averaged kinetic feedback of a powerful radio galaxy. In this work we attempt to solve the spectral age problem by observing two cluster-centre powerful radio galaxies; 3C320 and 3C444. With high-resolution broad-band Karl G. Jansky Very Large Array observations of the radio sources and deep XMM-Newton and Chandra observations of their hot intra-cluster media, coupled with the use of an analytic model, we robustly determine their spectral and dynamical ages. After finding self-consistent dynamical models that agree with our observational constraints, and accounting for sub-equipartition magnetic fields, we find that our spectral ages are still underestimated by a factor of two at least. Equipartition magnetic fields will underestimate the spectral age by factors of up to ~20. The turbulent mixing of electron populations in the radio lobes is likely to be the main remaining factor in the spectral age/dynamical age discrepancy, and must be accounted for in the study of large samples of powerful radio galaxies.
- [14] arXiv:1912.01029 [pdf, other]
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Title: GS 2000+25: The Least Luminous Black Hole X-ray BinaryAuthors: J. Rodriguez, R. Urquhart, R. M. Plotkin, T. Panurach, L. Chomiuk, J. Strader, J. C. A. Miller-Jones, E. Gallo, G. R. SivakofComments: 7 pages, 2 figures, accepted for publication in ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Little is known about the properties of the accretion flows and jets of the lowest-luminosity quiescent black holes. We report new, strictly simultaneous radio and X-ray observations of the nearby stellar-mass black hole X-ray binary GS 2000+25 in its quiescent state. In deep Chandra observations we detect the system at a faint X-ray luminosity of $L_X = 1.1^{+1.0}_{-0.7} \times 10^{30}\,(d/2 {\rm \,\, kpc})^2$ erg s$^{-1}$ (1-10 keV). This is the lowest X-ray luminosity yet observed for a quiescent black hole X-ray binary, corresponding to an Eddington ratio $L_X/L_{\rm Edd} \sim 10^{-9}$. In 15 hours of observations with the Karl G. Jansky Very Large Array, no radio continuum emission is detected to a $3\sigma$ limit of $< 2.8\ \mu$Jy at 6 GHz. Including GS 2000+25, four quiescent stellar-mass black holes with $L_X < 10^{32}$ erg s$^{-1}$ have deep simultaneous radio and X-ray observations and known distances. These sources all have radio to X-ray luminosity ratios generally consistent with, but slightly lower than, the low state radio/X-ray correlation for stellar-mass black holes with $L_X > 10^{32}$ erg s$^{-1}$. Observations of these sources tax the limits of our current X-ray and radio facilities, and new routes to black hole discovery are needed to study the lowest-luminosity black holes.
- [15] arXiv:1912.01042 [pdf, other]
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Title: Eddy evolution during large dust stormsJournal-ref: Icarus, 338 (2020)Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph)
The evolution of eddy kinetic energy during the development of large regional dust storms on Mars is investigated using the Mars Analysis Correction Data Assimilation (MACDA) reanalysis product and the dust storm data derived from Mars Global Surveyor Mars Daily Global Maps. Transient eddies in MACDA are decomposed into different components according to their eddy periods: $P\leq1$ sol, $1<P\leq8$ sols, $8<P\leq60$ sols. This paper primarily focuses on the Mars year 24 pre-solstice "A" storm that starts with many episodes of frontal/flushing dust storms from the northern hemisphere and attains its maximum global mean opacity after dust expansion in the southern hemisphere. During the development of this storm, the dominant eddies in terms of eddy kinetic energy progress from the $1<P\leq8$ sol eddies in the northern mid/high latitudes to the $P\leq1$ sol eddies (dominated by thermal tides) in the southern mid latitudes, and the $8<P\leq60$ sol eddies show a prominent peak with the increased global-mean dust opacity. The peaks of the $1<P\leq8$ sol eddies are found to best correlate with the average area of textured frontal/flushing dust storms within 40$^\circ$N $-$ 60$^\circ$N. The region where the $1<P\leq8$ sol eddies increase the most corresponds to the main flushing channel. The eddy kinetic energy of the $P\leq1$ eddies, dominated by $P$ = 1 and its harmonics, increases with the global mean dust opacity both before and after the winter solstice in Mars year 24. The $8<P\leq60$ sol eddies briefly spike during large, regional dust storms but remain weak if dust storm sequences do not lead to a major dust storm. Zonal wavenumber analysis of eddy kinetic energy shows that the peaks of the $1<P\leq8$ eddies often result from combinations of zonal wavenumbers 1 to 3, while the $P\leq1$ eddies and $8<P\leq60$ sol eddies are each dominated by zonal wavenumber 1.
- [16] arXiv:1912.01050 [pdf, other]
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Title: Reionization history constraints from neural network based predictions of high-redshift quasar continuaSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
Observations of the early Universe suggest that reionization was complete by $z\sim6$, however, the exact history of this process is still unknown. One method for measuring the evolution of the neutral fraction throughout this epoch is via observing the Ly$\alpha$ damping wings of high-redshift quasars. In order to constrain the neutral fraction from quasar observations, one needs an accurate model of the quasar spectrum around Ly$\alpha$, after the spectrum has been processed by its host galaxy but before it is altered by absorption and damping in the intervening IGM. In this paper, we present a novel machine learning approach, using artificial neural networks, to reconstruct quasar continua around Ly$\alpha$. Our QSANNdRA algorithm improves the error in this reconstruction compared to the state-of-the-art PCA-based model in the literature by 14.2% on average, and provides an improvement of 6.1% on average when compared to an extension thereof. In comparison with the extended PCA model, QSANNdRA further achieves an improvement of 22.1% and 16.8% when evaluated on low-redshift quasars most similar to the two high-redshift quasars under consideration, ULAS J1120+0641 at $z=7.0851$ and ULAS J1342+0928 at $z=7.5413$, respectively. Using our more accurate reconstructions of these two $z>7$ quasars, we estimate the neutral fraction of the IGM using a homogeneous reionization model and find $\bar{x}_\mathrm{HI} = 0.25^{+0.05}_{-0.05}$ at $z=7.0851$ and $\bar{x}_\mathrm{HI} = 0.60^{+0.11}_{-0.11}$ at $z=7.5413$. Our results are consistent with the literature and favour a rapid end to reionization.
- [17] arXiv:1912.01061 [pdf, other]
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Title: On the slope of curvature power spectrum in non-attractor inflationComments: 62 pages, 28 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
The possibility that primordial black holes constitute a fraction of dark matter motivates a detailed study of possible mechanisms for their production. Black holes can form by the collapse of primordial curvature fluctuations, if the amplitude of their small scale spectrum gets amplified by several orders of magnitude with respect to CMB scales. Such enhancement can for example occur in single-field, non-attractor inflation: in this work, we make a detailed investigation of the shape of the curvature spectrum in this scenario. We make use of an analytical approach based on a gradient expansion of curvature perturbations, which allows us to follow the changes in slope of the spectrum during its way from large to small scales. After encountering a dip in its amplitude, the spectrum can acquire steep slopes with a spectral index up to $n_s-1\,=\,8$, to then relax to a more gentle growth towards its peak as found in previous literature. After the peak associated with the non-attractor phase, the spectrum amplitude then mildly decays, during a transitional stage from non-attractor back to attractor evolution. Our analysis indicates that this gradient approach offers a transparent understanding of the contributions controlling the slope of the curvature spectrum. As an application of our findings, we characterise the slope in frequency of a stochastic gravitational wave background generated at second order from curvature fluctuations.
- [18] arXiv:1912.01062 [pdf, other]
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Title: CHILES VI: HI and H$α$ Observations for z < 0.1 Galaxies; Probing HI Spin Alignment with Filaments in the Cosmic WebAuthors: J. Blue Bird, J. Davis, N. Luber, J.H. van Gorkom, E. Wilcots, D.J. Pisano, H. B. Gim, E. Momjian, X. Fernandez, K. M. Hess, D. Lucero, R. Dodson, K. Vinsen, A. Popping, A. Chung, K. Kreckel, J. M. van der Hulst, M. YunComments: 24 pages, 25 figures, 6 tables, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present neutral hydrogen (HI) and ionized hydrogen (H${\alpha}$) observations of ten galaxies out to a redshift of 0.1. The HI observations are from the first epoch (178 hours) of the COSMOS HI Large Extragalactic Survey (CHILES). Our sample is HI biased and consists of ten late-type galaxies with HI masses that range from $1.8\times10^{7}$ M$_{\odot}$ to $1.1\times10^{10}$ M$_{\odot}$. We find that although the majority of galaxies show irregularities in the morphology and kinematics, they generally follow the scaling relations found in larger samples. We find that the HI and H${\alpha}$ velocities reach the flat part of the rotation curve. We identify the large-scale structure in the nearby CHILES volume using DisPerSE with the spectroscopic catalog from SDSS. We explore the gaseous properties of the galaxies as a function of location in the cosmic web. We also compare the angular momentum vector (spin) of the galaxies to the orientation of the nearest cosmic web filament. Our results show that galaxy spins tend to be aligned with cosmic web filaments and show a hint of a transition mass associated with the spin angle alignment.
- [19] arXiv:1912.01069 [pdf, other]
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Title: Atmospheric Density Uncertainty Quantification for Satellite Conjunction AssessmentComments: 15 pages, 6 figures, 5 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Space Physics (physics.space-ph)
Conjunction assessment requires knowledge of the uncertainty in the predicted orbit. Errors in the atmospheric density are a major source of error in the prediction of low Earth orbits. Therefore, accurate estimation of the density and quantification of the uncertainty in the density is required. Most atmospheric density models, however, do not provide an estimate of the uncertainty in the density. In this work, we present a new approach to quantify uncertainties in the density and to include these for calculating the probability of collision Pc. For this, we employ a recently developed dynamic reduced-order density model that enables efficient prediction of the thermospheric density. First, the model is used to obtain accurate estimates of the density and of the uncertainty in the estimates. Second, the density uncertainties are propagated forward simultaneously with orbit propagation to include the density uncertainties for Pc calculation. For this, we account for the effect of cross-correlation in position uncertainties due to density errors on the Pc. Finally, the effect of density uncertainties and cross-correlation on the Pc is assessed. The presented approach provides the distinctive capability to quantify the uncertainty in atmospheric density and to include this uncertainty for conjunction assessment while taking into account the dependence of the density errors on location and time. In addition, the results show that it is important to consider the effect of cross-correlation on the Pc, because ignoring this effect can result in severe underestimation of the collision probability.
- [20] arXiv:1912.01076 [pdf, other]
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Title: The Effect of Anisotropic Viscosity on the Nonlinear Kink InstabilityComments: 20 pagesJournal-ref: Communications in Nonlinear Science and Numerical Simulation, 105131Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph)
The kink instability of magnetohydrodynamics is believed to be fundamental to many aspects of the dynamic activity of the solar atmosphere, such as the initiation of flares and the heating of the solar corona. In this work, we investigate the importance of viscosity on the kink instability. In particular, we focus on two forms of viscosity; isotropic viscosity (independent of the magnetic field) and anisotropic viscosity (with a preferred direction following the magnetic field). Through the detailed analysis of magnetohydrodynamic simulations of the kink instability with both types of viscosity, we show that the form of viscosity has a significant effect on the nonlinear dynamics of the instability. The different viscosities allow for different flow and current structures to develop, thus affecting the behaviour of magnetic relaxation, the formation of secondary instabilities and the Ohmic and viscous heating produced. Our results have important consequences for the interpretation of solar observations of the kink instability.
- [21] arXiv:1912.01095 [pdf, other]
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Title: A simple, entropy-based dissipation trigger for SPHAuthors: Stephan RosswogComments: 11 pages, 10 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Computational Physics (physics.comp-ph)
Smoothed Particle Hydrodynamics (SPH) schemes need to be enhanced by dissipation mechanisms to handle shocks. Most SPH formulations rely on artificial viscosity and while this is working well in pure shocks, attention has to be payed to avoid dissipation where it is not wanted. Commonly used approaches include limiters and time-dependent dissipation parameters. The former try to distinguish shocks from other types of flows that do not require dissipation while in the latter approach the dissipation parameters are steered by some source term ("trigger") and, if not triggered, they decay to a pre-described floor value. The commonly used source terms trigger on either compression, $-\nabla\cdot\vec{v}$, or its time derive. Here we explore a novel way to trigger SPH-dissipation: based on the entropy growth rate between two time steps we identify "troubled particles" that need to have dissipation added because they are either passing through a shock wave or become noisy. Our new scheme is implemented into the Lagrangian hydrodynamics code MAGMA2 and scrutinized in a number of shock and fluid instability tests. We find excellent results in shocks and only a moderate (and desired) switch-on in instability tests, despite our conservatively chosen trigger parameters. The new scheme is robust, trivial to implement into existing SPH codes and does not add any computational overhead.
- [22] arXiv:1912.01099 [pdf, other]
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Title: Measuring the BAO peak position with different galaxy selectionsComments: 11 pages, 8 figures, 1 table, submitted to MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We investigate if, for a fixed number density of targets and redshift, there is an optimal way to select a galaxy sample in order to measure the baryon acoustic oscillation (BAO) scale, which is used as a standard ruler to constrain the cosmic expansion. Using the mock galaxy catalogue built by Smith et al. in the Millennium-XXL N-body simulation with a technique to assign galaxies to dark matter haloes based on halo occupation distribution modelling, we consider the clustering of galaxies selected by luminosity, colour and local density. We assess how well the BAO scale can be extracted by fitting a template to the power spectrum measured for each sample. We find that the BAO peak position is recovered equally well for samples defined by luminosity or colour, while there is a bias in the BAO scale recovered for samples defined by density. The BAO position is contracted to smaller scales for the densest galaxy quartile and expanded to large scales for the two least dense galaxy quartiles. For fixed galaxy number density, density-selected samples have higher uncertainties in the recovered BAO scale than luminosity- or colour-selected samples.
- [23] arXiv:1912.01102 [pdf, ps, other]
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Title: Magnetic OB[A] Stars with TESS: probing their Evolutionary and Rotational properties -- The MOBSTER CollaborationAuthors: A. David-Uraz (1), C. Neiner (2), J. Sikora (3), J. Barron (4 and 5), D. M. Bowman (6), P. Cerrahoğlu (1), D. H. Cohen (7), C. Erba (1), V. Khalack (8), O. Kobzar (8), O. Kochukhov (9), H. Pablo (10), V. Petit (1), M. E. Shultz (1), A. ud-Doula (11), G. A. Wade (5), the MOBSTER Collaboration ((1) Department of Physics and Astronomy, University of Delaware, (2) LESIA, Paris Observatory, PSL University, CNRS, Sorbonne University, Université de Paris, Meudon, France, (3) Physics and Astronomy Department, Bishop's University, Sherbrooke, Canada, (4) Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, ON, Canada, (5) Department of Physics and Space Physics, Royal Military College of Canada, Kingston, ON, (6) Institute of Astronomy, KU Leuven, Belgium, (7) Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA, (8) Département de Physique et d'Astronomie, Université de Moncton, Moncton, Canada, (9) Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden, (10) American Association of Variable Star Observers (AAVSO), Cambridge, MA, USA, (11) Penn State Scranton, Dunmore, PA, USA)Comments: 4 pages, Conference proceedings: "Stars and their variability observed from space", Vienna, Austria, 2019Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
In this contribution, we present the MOBSTER Collaboration, a large community effort to leverage high-precision photometry from the Transiting Exoplanet Survey Satellite (\textit{TESS}) in order to characterize the variability of magnetic massive and intermediate-mass stars. These data can be used to probe the varying column density of magnetospheric plasma along the line of sight for OB stars, thus improving our understanding of the interaction between surface magnetic fields and massive star winds. They can also be used to map out the brightness inhomogeneities present on the surfaces of Ap/Bp stars, informing present models of atomic diffusion in their atmospheres. Finally, we review our current and ongoing studies, which lead to new insights on this topic.
- [24] arXiv:1912.01132 [pdf, other]
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Title: Big-Bang Nucleosynthesis After PlanckComments: 63 pages, 22 figures. Comments welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
We assess the status of big-bang nucleosynthesis (BBN) in light of the final Planck data release and other recent developments, and in anticipation of future measurements. Planck data fix the cosmic baryon density to 0.9% precision, and determine the helium abundance and effective number of neutrinos with precision approaching that of astronomical and BBN determinations respectively. In addition, new high-redshift measurements give D/H to better precision than theoretical predictions, and new Li/H data reconfirm the lithium problem. We present new ${}^{7}{\rm Be}(n,p){}^{7}{\rm Li}$ rates using new neutron capture measurements; we have also examined the effect of proposed changes in the $d(p,\gamma){}^{3}{\rm He}$ rates. Using these results we perform a series of likelihood analyses. We assess BBN/CMB consistency, with attention to how our results depend on the choice of Planck data, as well as how the results depend on the choice of non-BBN, non-Planck data sets. Most importantly the lithium problem remains, and indeed is more acute given the very tight D/H observational constraints; new neutron capture data reveals systematics that somewhat increases uncertainty and thus slightly reduces but does not essentially change the problem. We confirm that $d(p,\gamma){}^{3}{\rm He}$ theoretical rates brings D/H out of agreement and slightly increases 7Li; new experimental data are needed at BBN energies. Setting the lithium problem aside, we find the effective number of neutrino species at BBN is $N_\nu = 2.86 \pm 0.15$. Future CMB Stage-4 measurements promise substantial improvements in BBN parameters: helium abundance determinations will be competitive with the best astronomical determinations, and $N_{\rm eff}$ will approach sensitivities capable of detecting the effects of Standard Model neutrino heating of the primordial plasma. (Abridged)
- [25] arXiv:1912.01141 [pdf, other]
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Title: Momentum Injection by Clustered Supernovae: Testing Subgrid Feedback PrescriptionsComments: 14 pages, 9 figures, accepted by MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
Using a 1D Lagrangian code specifically designed to assess the impact of multiple, time-resolved supernovae (SNe) from a single star cluster on the surrounding medium, we test three commonly used feedback recipes: delayed cooling (e.g., used in the GASOLINE-2 code), momentum-energy injection (a resolution-dependent transition between momentum-dominated feedback and energy-dominated feedback used, e.g., in the FIRE-2 code), and simultaneous energy injection (e.g., used in the EAGLE simulations). Our work provides an intermediary test for these recipes: we analyse a setting that is more complex than the simplified scenarios for which many were designed, but one more controlled than a full galactic simulation. In particular, we test how well these models reproduce the enhanced momentum efficiency seen for an 11 SN cluster simulated at high resolution (0.6 pc; a factor of 12 enhancement relative to the isolated SN case) when these subgrid recipes are implemented in low resolution (20 pc) runs. We find that: 1) the delayed cooling model performs well -- resulting in 9 times the momentum efficiency of the fiducial isolated SN value -- when SNe are clustered and $10^{51}$ erg are injected per SN, while clearly over-predicting the momentum efficiency in the single SN test case; 2) the momentum-energy model always achieves good results, with a factor of 5 boost in momentum efficiency; and 3) injecting the energy from all SNe simultaneously does little to prevent over-cooling and greatly under-produces the momentum deposited by clustered SNe, resulting in a factor of 3 decrease in momentum efficiency on the average.
- [26] arXiv:1912.01145 [pdf, ps, other]
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Title: Quasi-periodic pulsations of gamma-ray emissions from a solar flare on 2017 September 06Comments: 18 pages, 5 figures, accepted for publication in The Astrophysical JournalSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We investigate quasi-periodic pulsations (QPPs) of high-energy nonthermal emissions from an X9.3 flare (SOL2017-Sep-06T11:53), the most powerful flare since the beginning of solar cycle 24. The QPPs are identified as a series of regular and repeating peaks in the light curves in the gamma- and hard X-ray (HXR) channels recorded by the Konus-Wind, as well as the radio and microwave fluxes measured by the CALLISTO radio spectrograph during the impulsive phase. The periods are determined from the global wavelet and Fourier power spectra, as 24-30 s in the HXR and microwave channels which are associated with nonthermal electrons, and ~20 s in the gamma-ray band related to nonthermal ions. Both nonthermal electrons and ions may be accelerated by repetitive magnetic reconnection during the impulsive phase. However, we could not rule out other mechanisms such as the MHD oscillation in a sausage mode. The QPP detected in this study is useful for understanding the particle acceleration and dynamic process in solar flares and also bridging the gap between stellar and solar flares since the energy realm of the X9.3 solar flare is almost compared with a typical stellar flare.
- [27] arXiv:1912.01165 [pdf, ps, other]
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Title: Periodic mode changing in PSR J1048-5832Comments: 8 pages, 8 figures, 3 tables, accepted in MNRAS for publicationSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
By analysing the data acquired from the Parkes 64-m radio telescope at 1369 MHz, we report on the phase-stationary non-drift amplitude modulation observed in PSR J1048-5832. The high-sensitivity observations revealed that the central and trailing components of the pulse profile of this pulsar switch between a strong mode and a weak mode periodically. However, the leading component remains unchanged. Polarization properties of the strong and weak modes are investigated. Considering the similarity to mode changing, we argue that the periodic amplitude modulation in PSR J1048$-$5832 is periodic mode changing. The fluctuation spectral analysis showed that the modulation period is very short (~2.1 s or 17 P1), where P1 is the rotation period of the pulsar. We find that this periodic amplitude modulation is hard to explain by existing models that account for the periodic phenomena in pulsars like subpulse drifting.
- [28] arXiv:1912.01175 [pdf, other]
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Title: Barry and the BAO Model ComparisonComments: 17 pages, 13 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We compare the performance of four state-of-the-art models for extracting isotropic measurements of the Baryon Acoustic Oscillation (BAO) scale. To do this, we created a new, public, modular code Barry, which contains datasets, model fitting tools, and model implementations incorporating different descriptions of non-linear physics and algorithms for isolating the BAO feature. These are then evaluated for bias, correlation, and fitting strength using mock power spectra and correlation functions developed for the Sloan Digital Sky Survey Data Release 12. Our main findings are as follows: 1) All of the models can recover unbiased constraints when fit to the pre- and post-reconstruction simulations. 2) Models that provide physical descriptions of the damping of the BAO feature (using e.g., standard perturbation or effective-field theory arguments) report smaller errors on average, although the distribution of mock $\chi^{2}$ values indicates these are underestimated. 3) Allowing the BAO damping scale to vary can provide tighter constraints for some mocks, but is an artificial improvement that only arises when noise randomly sharpens the BAO peak. 4) Unlike recent claims in the literature when utilising a BAO Extractor technique, we find no improvement in the accuracy of the recovered BAO scale. 5) We implement a procedure for combining all models into a single consensus result that improves over the standard method without obviously underestimating the uncertainties. Overall, Barry provides an excellent framework for performing the cosmological analyses for upcoming surveys, and for rapidly testing and validating new models.
- [29] arXiv:1912.01184 [pdf, other]
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Title: Tidal disruption near black holes and their mimickersComments: 10 Pages, 4 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
Black holes and wormholes are solutions of Einstein's field equations, both of which, from afar, look like a central mass. We show here that although at large distances both behave like Newtonian objects, close to the event horizon or to the throat, black holes and wormholes have different tidal effects on stars, due to their respective geometries. We quantify this difference by a numerical procedure in the Schwarzschild black hole and the exponential wormhole backgrounds, and compare the peak fallback rates of tidal debris in these geometries. The tidal disruption rates in these backgrounds are also computed. It is shown that these quantities are a few times higher for wormholes, compared to the black hole cases.
- [30] arXiv:1912.01186 [pdf, ps, other]
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Title: LBT/PEPSI Spectropolarimetry of a Magnetic Morphology Shift in Old Solar-type StarsAuthors: Travis S. Metcalfe, Oleg Kochukhov, Ilya V. Ilyin, Klaus G. Strassmeier, Diego Godoy-Rivera, Marc H. PinsonneaultComments: 7 pages, 3 figures, 2 tables, ApJ Letters (accepted)Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Solar-type stars are born with relatively rapid rotation and strong magnetic fields. Through a process known as magnetic braking, the rotation slows over time as stellar winds gradually remove angular momentum from the system. The rate of angular momentum loss depends sensitively on the magnetic morphology, with the dipole field exerting the largest torque on the star. Recent observations suggest that the efficiency of magnetic braking may decrease dramatically in stars near the middle of their main-sequence lifetimes. One hypothesis to explain this reduction in efficiency is a shift in magnetic morphology from predominantly larger to smaller spatial scales. We aim to test this hypothesis with spectropolarimetric measurements of two stars that sample chromospheric activity levels on opposite sides of the proposed magnetic transition. As predicted, the more active star (HD 100180) exhibits a significant circular polarization signature due to a non-axisymmetric large-scale magnetic field, while the less active star (HD 143761) shows no significant signal. We identify analogs of the two stars among a sample of well-characterized Kepler targets, and we predict that the asteroseismic age of HD 143761 from future TESS observations will substantially exceed the age expected from gyrochronology. We conclude that a shift in magnetic morphology likely contributes to the loss of magnetic braking in middle-aged stars, which appears to coincide with the shutdown of their global dynamos.
- [31] arXiv:1912.01191 [pdf, ps, other]
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Title: Scale-invariance in the repeating fast radio burst 121102Comments: 7 pages, 5 figures, 6 tablesJournal-ref: MNRAS 491, 2156-2161 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The statistical properties of the repeating fast radio burst FRB 121102 are investigated. We find that the cumulative distributions of fluence, flux density, total energy and waiting time can be well fitted by the bent power law. In addition, the probability density functions of fluctuations of fluence, flux density and total energy well follow the Tsallis $q$-Gaussian distribution. The $q$ values keep steady around $q\sim 2$ for different scale intervals, indicating a scale-invariant structure of the bursts. The statistical properties of FRB 121102 are very similar to that of the soft gamma repeater SGR J1550-5418. The underlying physical implications need to be further investigated.
- [32] arXiv:1912.01232 [pdf, other]
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Title: ${\tt PlanetEvidence}$: Planet or Noise?Authors: Jacob Golomb (1), Graça Rocha (2,3), Tiffany Meshkat (4), Michael Bottom (2), Dimitri Mawet (3), Bertrand Mennesson (2), Gautam Vasisht (2), Jason Wang (3,5) ((1) University of Maryland, MD, (2) Jet Propulsion Laboratory, Pasadena, (3) California Institute of Technology, Pasadena, (4) Infrared Processing and Analysis Center, Pasadena, (5) 51 Pegasi b Fellow)Comments: 29 pages, 23 figures and 3 tables, submitted to ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
The work presented here attempts at answering the question: how do we decide when a given adetection is a planet or just residual noise in exoplanet direct imaging data? To this end we present a method implemented within a Bayesian framework: (1) to unify 'source detection', and, 'source characterization' into one single rigorous mathematical framework; (2) to enable an adequate hypothesis testing given the S/N of the data; (3) to enhance the detectability of planets faint signal in the presence of instrumental and background noise and to optimize the characterization of the planet. As a proof of concept we implemented a routine named ${\tt PlanetEvidence}$ that integrates the nested sampling technique (Multinest) with a post-processing technique, the Karhunen-Loeve Image Processing (KLIP), algorithm. This is a first step to recast such post-processing method into a fully Bayesian perspective. We test our approach on real direct imaging data, specifically using GPI data of $\beta$ Pictoris b, and, on synthetic data. We find that for the former the method strongly favors the presence of a planet (as expected) and recovers the true parameter posterior distributions. While for the latter case our approach allows us to detect (true) dim sources invisible to the naked eye as real planets, rather than background noise, and set a new lower threshold for detection at the 2$\sigma$ level approximately. Further it allows us to quantify our confidence that a given detection is a real planet and not just residual noise (for example residual speckles). The next natural step is to extend this approach to construct a Bayesian-based algorithm for blind detection, that is, not requiring an initial guess as to the location of the planet. This is the subject of ongoing work.
- [33] arXiv:1912.01240 [pdf]
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Title: Lunar impact craters identification and age estimation with Chang'E data by deep and transfer learningAuthors: Chen Yang, Haishi Zhao, Lorenzo Bruzzone, Jon Atli Benediktsson, Yanchun Liang, Bin Liu, Xingguo Zeng, Renchu Guan, Chunlai Li, Ziyuan OuyangComments: 6 pages, 3 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Impact craters, as "lunar fossils", are the most dominant lunar surface features and occupy most of the Moon's surface. Their formation and evolution record the history of the Solar System. Sixty years of triumphs in the lunar exploration projects accumulated a large amount of lunar data. Currently, there are 9137 existing recognized craters. However, only 1675 of them have been determined age, which is obviously not satisfactory to reveal the evolution of the Moon. Identifying craters is a challenging task due to their enormous difference in size, large variations in shape and vast presence. Furthermore, estimating the age of craters is extraordinarily difficult due to their complex and different morphologies. Here, in order to effectively identify craters and estimate their age, we convert the crater identification problem into a target detection task and crater age estimation into a taxonomy structure. From an initial small number of available craters, we progressively identify craters and estimate their age from Chang'E data by transfer learning (TL) using deep neural networks. For comprehensive identification of multi-scale craters, a two-stage craters detection approach is developed. Thus 117240 unrecognized lunar craters that range in diameter from 532 km to 1 km are identified. Then, a two-stage classification approach is developed to estimate the age of craters by simultaneously extracting their morphological features and stratigraphic information. The age of 79243 craters larger than 3 km in diameter is estimated. These identified and aged craters throughout the mid and low-latitude regions of the Moon are crucial for reconstructing the dynamic evolution process of the Solar System.
- [34] arXiv:1912.01256 [pdf, other]
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Title: How do WR binary components end their life? Is black hole formation accompanied by a supernova explosion? Evidence from high mass X-ray binariesComments: 6 pages, 6 figures, submitted for publication in A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
Theoretical population number studies of binaries with at least one black hole (BH) component are obviously depending on whether or not BHs receive a (natal) kick during their formation. Several observational facts seem to indicate that indeed BHs receive a kick during their formation. In the present paper we discuss additional evidence. The progenitors of wind fed high mass X-ray binaries (HMXB) with a BH component (BH HMXB) are WR+OB binaries where the WR star will finally collapse and form the BH. Starting from the observed population of WR+OB binaries in the Solar Neighborhood we predict the population of wind fed BH HMXBs as a function of the BH-natal kick. The simulations reveal that when WR stars collapse into a BH with zero or low kick, we would expect 100 or more wind fed BH HMXBs in the Solar Neighborhood whereas only one is observed (Cyg X-1). We consider this as evidence that BHs are formed with significant (natal) kicks.
- [35] arXiv:1912.01258 [pdf, other]
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Title: Multi-messenger hunts for heavy WIMPsAuthors: Geoff BeckComments: 6 pages, 4 figures, submitted to proceedings of SAIP annual conference 2019Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
Heavy neutrinos have a long history of consideration in the literature, in particular related to their role as solutions to the problems of neutrino mass, baryon asymmetry, and possibly dark matter. Interestingly, recent developments in the Madala hypothesis, a standard model extension designed to explain persistent LHC lepton anomalies, may also necessitate a heavy neutrino. This prospect is exciting as a dark matter model consisting of a TeV-scale leptophilic fermionic particle is also invoked to explain the electron-positron excess observed by the DAMPE experiment. The tantalising similarities between these new fermions may allow indirect dark matter detection methods to probe empirically compelling standard model extensions, like the Madala hypothesis. However, the leptophilic nature and large mass mean the expected gamma-ray signatures of annihilation or decay are weaker than those in the traditionally considered heavy quark and tau lepton channels. In this work we explore whether the KM3NeT neutrino detector could take advantage of the leptophilic nature of the added particle to provide an alternative means of exploring such interesting connections between cosmology and collider physics. We demonstrate that dwarf galaxies, in particular highly dense ultra-faint dwarf galaxies like Triangulum II, provide very strong prospects for KM3NeT searches.
- [36] arXiv:1912.01262 [pdf, ps, other]
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Title: Simultaneous photometric and spectral analysis of a new outburst of V1686 CygComments: 8 pages, 4 figures, 3 tablesSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present an analysis of the optical observations of Herbig AeBe star V1686 Cyg, which is associated with a small isolated star-forming region around HAeBe star BD+40$^{\circ}$4124. We observed this star as a part of our project of young eruptive stars investigation. Observations were held on 2.6m telescope of Byurakan Observatory from 2015 to 2017. For this period we obtained V1686 Cyg direct images and 14 medium- and low-resolution spectra. In the course of observations we noticed that this star underwent a not-typical brightness outburst. After data reduction we found that the full rise and decline of V1686 Cyg brightness had almost 3 magnitudes amplitude and lasted about 3 months. We were also able to trace the changes of the stellar spectrum during the outburst, which are correlated with the photometric variations.
- [37] arXiv:1912.01265 [pdf, other]
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Title: Crystallization of the inner crust of a neutron star and the influence of shell effectsComments: 9 pages, 9 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
Context. In the cooling process of a non-accreting neutron star, the composition and properties of the crust are thought to be fixed at the finite temperature where nuclear reactions fall out of equilibrium. A lower estimation for this temperature is given by the crystallization temperature, which can be as high as $\approx 7\times 10^9$ K in the inner crust, potentially leading to sizeable differences with respect to the simplifying cold-catalyzed matter hypothesis. Aims. We extend the recent work by Fantina et al. (2019) on the outer crust, to the study of the crystallization of the inner crust and the associated composition in the one-component plasma approximation. Methods. The finite temperature variational equations for non-uniform matter in both the liquid and the solid phases are solved using a compressible liquid-drop approach with parameters optimized on four different microscopic models which cover the present uncertainties in nuclear modeling. Results. We consider separately the effect of the different nuclear ingredients with their associated uncertainties, namely the nuclear equation of state, the surface properties in the presence of a uniform gas of dripped neutrons, and the proton shell effects arising from the ion single-particle structure. Our results suggest that the highest source of model dependence comes from the smooth part of the nuclear functional. Conclusions. We show that shell effects play an important role at the lowest densities close to the outer crust, but the most important physical ingredient to be settled for a quantitative prediction of the inner crust properties is the surface tension at extreme isospin values.
- [38] arXiv:1912.01271 [pdf, other]
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Title: The dynamo-wind feedback loop: Assessing their non-linear interplayComments: 9 pages, 5 figures, IAUS 354Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Though generated deep inside the convection zone, the solar magnetic field has a direct impact on the Earth space environment via the Parker spiral. It strongly modulates the solar wind in the whole heliosphere, especially its latitudinal and longitudinal speed distribution over the years. However the wind also influences the topology of the coronal magnetic field by opening the magnetic field lines in the coronal holes, which can affect the inner magnetic field of the star by altering the dynamo boundary conditions. This coupling is especially difficult to model because it covers a large variety of spatio-temporal scales. Quasi-static studies have begun to help us unveil how the dynamo-generated magnetic field shapes the wind, but the full interplay between the solar dynamo and the solar wind still eludes our understanding.
We use the compressible magnetohydrodynamical (MHD) code PLUTO to compute simultaneously in 2.5D the generation and evolution of magnetic field inside the star via an alpha-Omega dynamo process and the corresponding evolution of a polytropic coronal wind over several activity cycles for a young Sun. A multi-layered boundary condition at the surface of the star connects the inner and outer stellar layers, allowing both to adapt dynamically. Our continuously coupled dynamo-wind model allows us to characterize how the solar wind conditions change as a function of the cycle phase, and also to quantify the evolution of integrated quantities such as the Alfv\'en radius. We further assess the impact of the solar wind on the dynamo itself by comparing our results with and without wind feedback. - [39] arXiv:1912.01298 [pdf, other]
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Title: Fourier series for eclipses on exoplanet binariesComments: 12 pages, 10 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
A double planet system or planet binary undergoes eclipses that modify the reflective light curve. In the time domain, the eclipse events are fast and weak. This would make their signal difficult to find and recognize in the phase light curve, even for small inclinations when eclipses happen frequently. However, due to the quasiperiodic nature of the phenomenon, the Fourier transform of the direct reflection signal consists of a double sum of sharp peaks. These peaks can be resolved for large close binaries and sufficiently long observation times with a star coronagraph. Eclipses modulate the phase curve, having an orbital period $2\pi/\omega$, with a contribution from the relative motion in the binary plane of a period $2\pi/\Omega$. This leads to a spectral structure with basis frequencies $\omega$ and $\Omega$. We aim to characterize these spectra. We studied the regime of short eclipses that occur when the planet radii are small compared to the planet separation. We derived formulas for the peak amplitudes applicable to homogeneous (Lambertian) planet binaries in circular orbit with small inclination. The effects of an eclipse and of double reflection appear as first- and second-order contributions (in planet radius over separation) in the reflection signal respectively. Small peaks appear as observable side bands in the spectrum. Identical structures around $m\Omega$ are characteristic of short-duration eclipses. Deceasing side bands could indicate double reflection between companions. Fourier analysis of the light curve of non-transiting planets can be used to find planets and their moons. Difficulties in interpreting the structures arise for small planet separation and when there are several moons in mean-motion resonance.
- [40] arXiv:1912.01317 [pdf, ps, other]
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Title: Multimessenger search for evaporating primordial black holesJournal-ref: Proceedings of the International Conference "SN 1987A, Quark Phase Transition in Compact Objects and Multimessenger Astronomy", Russia, Terskol (BNO INR RAS), Nizhnij Arkhyz (SAO RAS), 2-8 July 2017, INR RAS, Moscow, 2018, p. 158Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Primordial black holes (PBHs) are black holes which may form in the early Universe through the gravitational collapse of primordial cosmological density fluctuations. Due to Hawking radiation these PBHs are supposed to evaporate by emitting particles. Recent developments in the experimental searching for evaporating PBHs in the local Universe are reviewed. The multimessenger techniques of searching for signals from evaporating PBHs are discussed.
- [41] arXiv:1912.01325 [pdf, ps, other]
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Title: Observational Aspect of Black Hole Dark MatterAuthors: Leo StodolskyComments: eight pages, no figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
Advances in high angular resolution astronomy make it conceivable that black hole dark matter could be detected via angular deviation effects. Assuming the dark matter in the galaxy is made of solar mass black holes, there is a non-trivial probability that a line-of-sight through the galaxy, leads to micro-arcseconds deviations, a value that has been discussed for various astronomical projects. In cosmology the effects are magnified by an increased density at early times and an opening of angles due to redshift. If the dark matter is made of primordial black holes, present at the CMB, random deflections of the CMB photons lead to a limit on the angular resolution, approximately ${3}\times 10^{-7} \sqrt{M/M_\odot}\, rad$, with $M$ the mass of the black holes. Using the resolutions of $\sim 10^{-3} rad$ demonstrated in observations of the ``acoustic peaks '' then implies the limit $(M/M_\odot)\lesssim 10^{7}$. While this large value seems uninteresting, improved resolutions would lead to significant limits or conceivably the discovery of primordial black holes.
- [42] arXiv:1912.01360 [pdf, ps, other]
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Title: An apparently eccentric orbit of the exoplanet WASP-12 b as a radial velocity signature of planetary-induced tides in the host starComments: Accepted for publication in ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Massive exoplanets on extremely tight orbits, such as WASP-12 b, induce equilibrium tides in their host stars. Following the orbital motion of the planet, the tidal fluid flow in the star can be detected with the radial velocity method. Its signature manifests as the second harmonics of the orbital frequency that mimics a non-zero orbital eccentricity. Using the new radial velocity measurements acquired with the HARPS-N spectrograph at the Telescopio Nazionale Galileo and combining them with the literature data, we show that the apparent eccentricity of WASP-12 b's orbit is non-zero at a 5.8 sigma level, and the longitude of periastron of this apparently eccentric orbit is close to 270 degrees. This orbital configuration is compatible with a model composed of a circular orbit and a signature of tides raised in the host star. The radial velocity amplitude of those tides was found to be consistent with the equilibrium tide approximation. The tidal deformation is predicted to produce a flux modulation with an amplitude of 80 ppm which could be detected using space-born facilities.
- [43] arXiv:1912.01361 [pdf, other]
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Title: An image of the dust sublimation region in the nucleus of NGC 1068Authors: GRAVITY Collaboration, O. Pfuhl, R. Davies, J. Dexter, H. Netzer, S. Hoenig, D. Lutz, M. Schartmann, E. Sturm, A. Amorim, W. Brandner, Y. Clenet, P. T. de Zeeuw, A. Eckart, F. Eisenhauer, N. M. Foerster Schreiber, F. Gao, P. J. V. Garcia, R. Genzel, S. Gillessen, D. Gratadour, M. Kishimoto, S. Lacour, F. Millour, T. Ott, T. Paumard, K. Perraut, G. Perrin, B. M. Peterson, P. O. Petrucci, M. A. Prieto, D. Rouan, J. Shangguan, T. Shimizu, A. Sternberg, O. Straub, C. Straubmeier, L. J. Tacconi, K. R. W. Tristram, P. Vermot, I. Waisberg, F. Widmann, J. WoillezComments: Accepted for publication in Astronomy and Astrophysics. 13 pages with 7 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present near-infrared interferometric data on the Seyfert 2 galaxy NGC 1068, obtained with the GRAVITY instrument on the European Southern Observatory Very Large Telescope Interferometer. The extensive baseline coverage from 5 to 60 M\lambda allowed us to reconstruct a continuum image of the nucleus with an unrivaled 0.2 pc resolution in the K-band. We find a thin ring-like structure of emission with a radius r = 0.24+/-0.03 pc, inclination i = 70+/-5 deg, position angle PA = -50+/-4 deg, and h/r < 0.14, which we associate with the dust sublimation region. The observed morphology is inconsistent with the expected signatures of a geometrically and optically thick torus. Instead, the infrared emission shows a striking resemblance to the 22 GHz maser disc, which suggests they share a common region of origin. The near-infrared spectral energy distribution indicates a bolometric luminosity of (0.4-4.7) x 10^45 erg/s, behind a large A_K ~ 5.5 (A_V ~ 90) screen of extinction that also appears to contribute significantly to obscuring the broad line region.
- [44] arXiv:1912.01415 [pdf, other]
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Title: From Sun to interplanetary space: What is the pathlength of Solar Energetic Particles?Authors: T. Laitinen, S. Dalla (Jeremiah Horrocks Institute, University of Central Lancashire, Preston, UK)Comments: 10 pages, 4 figures; Accepted for publication in Astrophysical JournalSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)
Solar energetic particles (SEPs), accelerated during solar eruptions, propagate in turbulent solar wind before being observed with in situ instruments. In order to interpret their origin through comparison with remote-sensing observations of the solar eruption, we thus must deconvolve the transport effects due to the turbulent magnetic fields from the SEP observations. Recent research suggests that the SEP propagation is guided by the turbulent meandering of the magnetic fieldlines across the mean magnetic field. However, the lengthening of the distance the SEPs travel, due to the fieldline meandering, has so far not been included in SEP event analysis. This omission can cause significant errors in estimation of the release times of SEPs at the Sun. We investigate the distance travelled by the SEPs by considering them to propagate along fieldlines that meander around closed magnetic islands that are inherent in turbulent plasma. We introduce a fieldline randow walk model which takes into account the physical scales associated to the magnetic islands. Our method remedies the problem of the diffusion equation resulting in unrealistically short pathlengths, and the fractal dependence of the pathlength of random walk on the length of the random-walk step. We find that the pathlength from the Sun to 1 au can be below the nominal Parker spiral length for SEP events taking place at solar longitudes 45E to 60W, whereas the western and behind-the-limb particles can experience pathlengths longer than 2 au due to fieldline meandering.
- [45] arXiv:1912.01418 [pdf, other]
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Title: Time variability of low angular momentum accretion flows around black holeComments: 9 pages, 4 figures, contribution to the Proceedings of the High Energy Phenomena in Relativistic Outflows VII - HEPRO VII, Barcelona, Spain (submitted in PoS (Proceedings of Science) )Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We present the relativistic 2D and 3D GRMHD simulation of axisymmetric, inviscid, hydrodynamic accretion flows in a fixed Kerr black hole gravitational field. The flow is having low angular momentum with respect to Keplerian one. A relativistic fluid where its bulk velocity is comparable to the speed of light, flowing in the accretion disk very close to the horizon should be described by adiabtic index: 4=3 < g < 5=3 .The time dependent evolution of shock position and respective effect on mass accretion rate and oscillation frequency with varying adiabatic index has been studied. Here we present some of the results for adiabatic index = 1.4 in a 2D and 3D model.
- [46] arXiv:1912.01472 [pdf, other]
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Title: The Sub-millimeter Rotational Spectrum of Ethylene Glycol up to 890 GHz and Application to ALMA Band 10 Spectral Line Data of NGC 6334IAuthors: Mattia Melosso, Luca Dore, Filippo Tamassia, Crystal L. Brogan, Todd R. Hunter, Brett A. McGuireComments: accepted in the Journal of Physical Chemistry ASubjects: Astrophysics of Galaxies (astro-ph.GA)
The rotational spectrum of the most stable conformer of ethylene glycol (HO(CH$_2$)$_2$OH) has been recorded between 360-890 GHz using a frequency-modulation sub-millimeter spectrometer. The refinement and extension of the spectroscopic parameters over previous efforts provides predicted catalog frequencies for ethylene glycol with sufficient accuracy for comparison to high-frequency astronomical data. The improvement in the cataloged line positions, and the need for improved accuracy enabled by high-frequency laboratory work, is demonstrated by an analysis of ethylene glycol emission at 890 GHz in the high-mass star-forming region NGC 6334I in ALMA Band 10 observations. The need for accurate rotational spectra at sub-millimeter wavelengths/THz frequencies is discussed.
- [47] arXiv:1912.01481 [pdf, ps, other]
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Title: The International Virtual Observatory Alliance in 2019Authors: Mark A. Allen, Patrick Dowler, Janet D. Evans, Chenzhou Cui, Tim Jenness, Bruno Merin, G. Bruce Berriman, J. J. KavelaarsComments: 4 pages, submitted to proceedings of ADASS XXIV to be published in ASP Conf. SeriesSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
The International Virtual Observatory Alliance (IVOA) held its bi-annual Interoperability Meetings in May 2019, and in October 2019 following the ADASS XXIX conference. We provide a brief report on the status of the IVOA and the activities of the Interoperability Meetings.
- [48] arXiv:1912.01518 [pdf, ps, other]
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Title: Effects of the general relativistic spin precessions on the habitability of rogue planets orbiting supermassive black holesAuthors: Lorenzo IorioComments: LaTex2e, 15 pages, 2 figures, no tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); General Relativity and Quantum Cosmology (gr-qc); Popular Physics (physics.pop-ph); Space Physics (physics.space-ph)
Recently, the possibility that many starless telluric planets may form around supermassive black holes (SMBHs) receiving an energy input from the hole's accretion disk which, under certain not implausible circumstances, may make them habitable in a terrestrial sense has gained increasing attention. In particular, an observer on a planet orbiting at distance $r=100$ Schwarzschild radii from a SMBH with mass $M_\bullet = 1\times 10^8\,\mathrm{M}_\odot$ in a plane slightly outside the equator of the latter would see the gravitationally lensed accretion disk with the same size of the Sun as seen from the Earth. Moreover, the accretion rate might be set in such a way that the apparent disk's temperature would be identical to that of the solar surface. We demonstrate that the post-Newtonian (pN) de Sitter and Lense-Thirring precessions of the spin axis of such a world would change, among other things, its tilt $\varepsilon$ to its orbital plane by tens to hundreds of degrees over a time span of, say, just $\Delta t =400\,\mathrm{yr}$, depending on the obliquity $\eta_\bullet$ of the SMBH's spin to the orbital plane. Thus, such relativistic effects would have a relevant impact on the long term habitability of the considered planet. It is plausible arguing that much stronger effects would likely alter the sky as seen from the fictional planets appearing in the movie \textit{Interstellar}, which orbit much closer to the event horizon of the SMBH Gargantua.
- [49] arXiv:1912.01531 [pdf, other]
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Title: Disentangling Cataclysmic Variables in Gaia's HR-DiagramComments: 5 pages, 12 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
Cataclysmic Variables (CVs) are interacting binaries consisting of at least three components that control their colour and magnitude. Using Gaia we here investigate the influence of the physical properties of these binaries on their position in the Hertzsprung-Russell diagram (HR-diagram). The CVs are on average located between the main sequence and the white dwarf regime, the maximum density being at $G_{BP}-G_{RP} \sim 0.56$ and $G_{abs} \sim 10.15$. We find a trend of the orbital period with colour and absolute brightness: with decreasing period, the CVs become bluer and fainter. We also identify the location of the various CV sub-types in the HR-diagram and discuss the possible location of detached CVs, going through the orbital period gap.
- [50] arXiv:1912.01550 [pdf, ps, other]
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Title: Supernovae Ia in 2019 (review): a rising demand for spherical explosionsAuthors: Noam Soker (Technion, Israel)Comments: A review paper. Will be submitted in a two days to allow comments by readersSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
I review new studies of type Ia supernovae (SNe Ia) from 2019, and use these to improve the comparison between the five binary SN Ia scenarios. New low polarisation measurements solidify the claim that most SN Ia explosions are globally spherically symmetric (clumps are possible). Explosions by dynamical processes, like explosions that take place during a merger process of two white dwarfs (WDs) in the double degenerate (DD) scenario, or during an accretion process in the double detonation (DDet) scenario and in the single degenerate (SD) scenario, lead to non-spherical explosions, in contradiction with observations of normal SNe Ia. I argue that these (DD, DDet, SD) scenarios account mainly for peculiar SNe Ia. The explosion of a Chandrasekhar mass Mch WD (deflagration to detonation process) has a global spherical structure that is compatible with observations. To reach spherical explosions, SN Ia scenarios should allow for a time delay between the formation of an Mch-WD and its explosion. As such, I split the DD scenario to a channel without merger to explosion delay (MED) time (that forms mainly peculiar SNe Ia), and a channel with a MED, the DD-MED channel (scenario). I speculate that the main contributors to normal SNe Ia are the core degenerate (CD) scenario, the DD-MED scenario, both have Mch spherical explosions, and the DD scenario that has sub-Mch non-spherical explosions.
- [51] arXiv:1912.01569 [pdf, ps, other]
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Title: Habitability on local, Galactic and cosmological scalesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
The aim of this paper is to underline conditions necessary for the emergence and development of life. They are placed at local planetary scale, at Galactic scale and within the cosmological evolution, as pointed out by the Anthropic Cosmological Principle. We will consider the circumstellar habitable zone (CHZ) for planetary systems and a Galactic Habitable Zone (GHZ) including also a set of strong cosmological constraints to allow life (cosmological habitability (COSH)). Some requirements are specific of a single scale and its related physical phenomena, while others are due to the conspired effects occurring at more than one scale. The scenario emerging from this analysis is that all the habitability conditions here detailed must at least be met. Then life asks something which may appear as "a monstrous sequence of accidents" as Hoyle (1959) thought, or as providential collaborations leading to realize how finely tuned is the architecture within which Life, as precious stone, is embedded.
- [52] arXiv:1912.01572 [pdf, ps, other]
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Title: MAXI/SSC All-sky maps from 0.7 keV to 4 keVAuthors: Satoshi Nakahira, Hiroshi Tsunemi, Hiroshi Tomida, Shinya Nakashima, Ryuho Kataoka, Kazuo MakishimaComments: Submitted to Publications of the Astronomical Society of Japan on August 30 2019, Accepted by PASJ on December 02 2019Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
By accumulating data from the Solid-state Slit Camera (SSC) on board the MAXI mission for 2 years from 2009 to 2011, diffuse X-ray background maps were obtained in energies of 0.7--1.0, 1.0--2.0, and 2.0--4.0 keV. They are the first ones that were derived with a solid-state instrument, and to be compared with the previous ROSAT all sky survey result. While the SSC map in the highest energy band is dominated by point sources and the Galactic Diffuse X-ray emission, that in 0.7--1.0 keV reveals an extended X-ray structure, of which the brightness distribution is very similar to that observed with ROSAT about 20 years before. Like in the ROSAT result, the emission is dominated by a bright arc-like structure, which appears to be a part of a circle of $\sim 50^\circ$ radius centered at about $(l, b) \sim (340^\circ, 15^\circ)$. In addition, the SSC map suggests a fainter and larger ellipse, which is elongated in the north-south direction and roughly centered at the Galactic center. The spectrum of these structures is explained as thin thermal emission from a plasma, with a temperature of $\sim 0.31$ keV and an abundance of $\sim0.3$ Solar. Based on SSC observation conditions including the low Solar activity, the Solar Wind Charge Exchange signals are estimated to be negligible in the present SSC maps, as well as in the $>0.56$ keV ROSAT map. A brief discussion is given to the obtained results.
Cross-lists for Wed, 4 Dec 19
- [53] arXiv:1911.13216 (cross-list from hep-th) [pdf, other]
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Title: Effects of oscillating spacetime metric background on a complex scalar field and formation of topological vorticesComments: 12 pages, 10 figuresSubjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); Quantum Gases (cond-mat.quant-gas); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory (nucl-th)
We study time evolution of complex scalar field in the symmetry broken phase in presence of oscillating spacetime metric background. In our (2+1)-dimensional simulations, we show that the spacetime oscillations excite the initial 'small' fluctuations of the field configuration. This field excitations occur for a wide range of frequencies of spacetime metric. For smaller frequencies mostly the transverse excitations(Goldstone modes) dominate, while for larger frequencies longitudinal excitations(radial modes) of the field also get generated. For a given system size, there is a lower cut-off of the frequency of spacetime oscillations below which we do not see large enhancement in the fluctuations of the field. At a particular stage of field evolution, spacetime oscillation generates a periodic variation of phase of field in the physical space. This periodic spatial variation of phase of field oscillates in some time duration about its initial configuration with the frequency of spacetime oscillation, which shows that these excitations arise due to the phenomena of parametric resonance. We find that these field excitations at later stage lead to the formation of vortex-antivortex pairs. At sufficient large time of field evolution, field configuration achieves a disorder state. For some parameters of the theory, we see the formation of vortex-antivortex lattice structure in the system. This study suggests that spacetime oscillations may play an important role in the time evolution of the superfluid phase inside neutron stars during the binary neutron star (BNS) merger.
- [54] arXiv:1912.00325 (cross-list from gr-qc) [pdf, other]
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Title: Simulating the scattering of low-frequency Gravitational Waves by compact objects using the finite element methodAuthors: Jian-hua He (NJU)Comments: 15 pages, 8 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
We investigate the wave effects of gravitational waves (GWs) using numerical simulations with the finite element method (FEM) based on the publicly available code {\it deal.ii}. We robustly test our code using a point source monochromatic spherical wave. We examine not only the waveform observed by a local observer but also the global energy conservation of the waves. We find that our numerical results agree very well with the analytical predictions. Based on our code, we study the scattering of GWs by compact objects. Using monochromatic waves as the input source, we find that if the wavelength of GWs is much larger than the Schwarzschild radius of the compact object, the amplitude of the total scattered GWs does not change appreciably due to the strong diffraction effect, for an observer far away from the scatterer. This finding is consistent with the results reported in the literature. However, we also find that, near the scatterer, not only the amplitude of the scattered waves is very large, comparable to that of the incident waves, but also the phase of the GWs changes significantly due to the interference between the scattered and incident waves. As the evolution of the phase of GWs plays a crucial role in the matched filtering technique in extracting GW signals from the noisy background, our findings suggest that wave effects should be taken into account in the data analysis in the future low-frequency GW experiments, if GWs are scattered by nearby compact objects in our local environment.
- [55] arXiv:1912.01007 (cross-list from hep-ph) [pdf, other]
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Title: Gravitational wave probes of axion-like particlesComments: 6 pages, 3 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We have recently shown that axions and axion-like particles (ALPs) may emit an observable stochastic gravitational wave (GW) background when they begin to oscillate in the early universe. In this note, we identify the regions of ALP parameter space which may be probed by future GW detectors, including ground- and space-based interferometers and pulsar timing arrays. Interestingly, these experiments have the ability to probe axions from the bottom up, i.e. in the very weakly coupled regime which is otherwise unconstrained. Furthermore, we discuss the effects of finite dark photon mass and kinetic mixing on the mechanism, as well as the (in)sensitivity to couplings of the axion to Standard Model fields. We conclude that realistic axion and ALP scenarios may indeed be probed by GW experiments in the future, and provide signal templates for further studies.
- [56] arXiv:1912.01014 (cross-list from hep-ph) [pdf, other]
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Title: Neutrino and positron constraints on spinning primordial black hole dark matterComments: v1: 8 pages, 6 figures. Comments welcomeSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
Angular momentum is a fundamental property of a black hole and is known to have a strong effect on its evaporation rate. It has recently been postulated that primordial black holes can have substantial spin. We conduct a comprehensive study of the detectability of primordial black holes with non-negligible spin, via the searches for the diffuse supernova neutrino background and observation of the 511 keV gamma-ray line from positrons in the Galactic center, setting competitive constraints. Spinning primordial black holes are probed up to a slightly higher mass range compared to non-spinning ones. Our constraint using neutrinos is slightly weaker than that due to the diffuse gamma-ray background. We find that the positron constraints are typically weaker in the lower mass range and stronger in the higher mass range for the spinning primordial black holes compared to the non-spinning ones. They are generally stronger than those derived from the diffuse gamma-ray measurements for primordial black holes having masses greater than a few $\times \, 10^{16}$g.
- [57] arXiv:1912.01393 (cross-list from hep-th) [pdf, other]
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Title: Galileon scalar electrodynamicsComments: 22 Pages, 1 FigureSubjects: 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)
We construct a consistent model of Galileon scalar electrodynamics. The model satisfies three essential requirements: (1) The action contains higher-order derivative terms, and obey the Galilean symmetry, (2) Equations of motion also satisfy Galilean symmetry and contain only up to second-order derivative terms in the matter fields and, hence do not suffer from instability, and (3) local U(1) gauge invariance is preserved. We show that the non-minimal coupling terms in our model are different from that of the real scalar Galileon models; however, the equations of motion are identical. We show that the model can lead to an accelerated expansion in the early Universe. We discuss the implications of the model for cosmological inflation.
- [58] arXiv:1912.01461 (cross-list from nucl-th) [pdf, other]
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Title: Probing the equation of state of neutron star matter with gravitational waves from binary inspirals in light of GW170817: a brief reviewComments: 24 pages, 6 Figures. Topical Review for Journal of Physics G Special Issue "Hadrons & Gravitational Waves After GW170817"Journal-ref: J.Phys. G46 (2019) no.12, 123002Subjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
Neutron stars are unique testbeds for exploring the physics of strongly interacting matter in extreme regimes of density, temperature, and isospin that are not accessible anywhere else in the universe. The nature of neutron star matter can now be probed with gravitational-waves (GWs) from binary driven by nonlinear gravity, where phenomena such as tidal effects lead to characteristic matter-dependent GW signatures. We focus here on the dominant tidal GW imprints that were most relevant for the event GW170817. We review the role of the tidal deformability parameter, its definition, computation, and relation to the equation of state. We briefly discuss the implications of GW170817, representing the first-ever constraints on tidal deformability from GW data. Finally, we outline opportunities and challenges for probing subatomic physics with GWs, as the measurements will become more precise and will probe a diversity of the binary neutron star population in the coming years.
Replacements for Wed, 4 Dec 19
- [59] arXiv:1706.05664 (replaced) [pdf, ps, other]
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Title: High-mass star formation in Orion possibly triggered by cloud-cloud collision III, NGC2068 and NGC2071Authors: Shinji FUJITA, Daichi TSUTSUMI, Akio OHAMA, Asao HABE, Nirmit SAKRE, Kazuki OKAWA, Mikito KOHNO, Yusuke HATTORI, Atsushi NISHIMURA, Kazufumi TORII, Hidetoshi SANO, Kengo TACHIHARA, Kimihiro KIMURA, Hideo OGAWA, Yasuo FUKUIComments: 20 peges, 7 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [60] arXiv:1802.06039 (replaced) [pdf, other]
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Title: Projected WIMP sensitivity of the LUX-ZEPLIN (LZ) dark matter experimentAuthors: D.S. Akerib, C.W. Akerlof, S.K. Alsum, H.M. Araújo, M. Arthurs, X. Bai, A.J. Bailey, J. Balajthy, S. Balashov, D. Bauer, J. Belle, P. Beltrame, T. Benson, E.P. Bernard, T.P. Biesiadzinski, K.E. Boast, B. Boxer, P. Brás, J.H. Buckley, V.V. Bugaev, S. Burdin, J.K. Busenitz, C. Carels, D.L. Carlsmith, B. Carlson, M.C. Carmona-Benitez, C. Chan, J.J. Cherwinka, A. Cole, A. Cottle, W.W. Craddock, A. Currie, J.E. Cutter, C.E. Dahl, L. de Viveiros, A. Dobi, J.E.Y. Dobson, E. Druszkiewicz, T.K. Edberg, W.R. Edwards, A. Fan, S. Fayer, S. Fiorucci, T. Fruth, R.J. Gaitskell, J. Genovesi, C. Ghag, M.G.D. Gilchriese, M.G.D.van der Grinten, C.R. Hall, S. Hans, K. Hanzel, S.J. Haselschwardt, S.A. Hertel, S. Hillbrand, C. Hjemfelt, M.D. Hoff, J.Y-K. Hor, D.Q. Huang, C.M. Ignarra, W. Ji, A.C. Kaboth, et al. (116 additional authors not shown)Comments: 14 pages, 11 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det)
- [61] arXiv:1810.03443 (replaced) [pdf, other]
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Title: Search for anomalous features in gamma-ray blazar spectra corrected for the absorption on the extragalactic background lightComments: V2: 40 pages, 16 figures (43 panels). Considerable changes in the blazar sample resulted in reduced significance; discussions extended - version accepted by JCAPJournal-ref: JCAP 12(2019)002Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [62] arXiv:1903.05103 (replaced) [pdf, other]
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Title: Strong lensing models of eight CLASH clusters from extensive spectroscopy: accurate total mass reconstructions in the coresAuthors: G. B. Caminha, P. Rosati, C. Grillo, G. Rosani, K. I. Caputi, M. Meneghetti, A. Mercurio, I. Balestra, P. Bergamini, A. Biviano, M. Nonino, K. Umetsu, E. Vanzella, M. Annunziatella, T. Broadhurst, C. Delgado-Correal, R. Demarco, A. M. Koekemoer, M. Lombardi, C. Maier, M. Verdugo, A. ZitrinComments: 27 pages, 9 figures, 7 tables, updated to match the published version. Full redshift catalogue and lensing models are available at this http URLJournal-ref: A&A 632, A36 (2019)Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [63] arXiv:1904.00024 (replaced) [pdf, other]
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Title: BAO Modulation as a Probe of Compensated Isocurvature PerturbationsComments: Fixed mismatch of arxiv abstract vs pdf in previous version. 16 pages, 4 figuresJournal-ref: Phys. Rev. D 100, 063503 (2019)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [64] arXiv:1905.01103 (replaced) [pdf, ps, other]
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Title: Reconstruction of Dynamical Dark Energy Potentials: Quintessence, Tachyon and interacting modelsComments: 9 pages, 5 figures, minor corrections and references updated. Final versionJournal-ref: J Astrophys Astron (2019) 40: 44Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [65] arXiv:1905.04670 (replaced) [pdf]
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Title: A Pulsar Wind Nebula Embedded in the Kilonova AT2017gfo Associated with GW 170817/GRB 170817AAuthors: Jia Ren, Da-Bin Lin, Lu-Lu Zhang, Xiao-Yan Li, Tong Liu, Rui-Jing Lu, Xiang-Gao Wang, En-Wei LiangComments: 9 pages, 7 figures and 1 tableJournal-ref: The Astrophysical Journal, Volume 885, Issue 1, article id. 60, 9 pp. (2019)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [66] arXiv:1905.08696 (replaced) [pdf, other]
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Title: How to add massive neutrinos to your $Λ$CDM simulation -- extending cosmology rescaling algorithmsComments: 15 pages, 11 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [67] arXiv:1905.10388 (replaced) [pdf, other]
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Title: Dedalus: A Flexible Framework for Numerical Simulations with Spectral MethodsComments: 40 pages, 18 figures. Accepted to Physical Review ResearchSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Computational Physics (physics.comp-ph); Fluid Dynamics (physics.flu-dyn)
- [68] arXiv:1906.02832 (replaced) [pdf, other]
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Title: Self-induced Scattering of Strahl Electrons in the Solar WindAuthors: Daniel Verscharen (UCL, UNH), Benjamin D. G. Chandran (UNH), Seong-Yeop Jeong (UCL), Chadi S. Salem (UCB), Marc P. Pulupa (UCB), Stuart D. Bale (UCB, Imperial College)Comments: 11 pages, 11 figuresJournal-ref: Astrophys. J. 886, 2, 2019Subjects: Space Physics (physics.space-ph); Solar and Stellar Astrophysics (astro-ph.SR); Geophysics (physics.geo-ph); Plasma Physics (physics.plasm-ph)
- [69] arXiv:1906.06615 (replaced) [pdf, other]
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Title: Detecting new signals under background mismodellingAuthors: Sara AlgeriSubjects: Data Analysis, Statistics and Probability (physics.data-an); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Phenomenology (hep-ph); Methodology (stat.ME)
- [70] arXiv:1907.04333 (replaced) [pdf, other]
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Title: Baryons in the CosmicWeb of IllustrisTNG -- II: the Connection among Galaxies, Halos, their Formation Time and their Location in the Cosmic WebAuthors: Davide Martizzi, Mark Vogelsberger, Paul Torrey, Annalisa Pillepich, Steen H. Hansen, Federico Marinacci, Lars HernquistComments: Accepted by MNRAS. 12 pages, 6 figures, 3 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [71] arXiv:1907.10623 (replaced) [pdf, other]
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Title: Global Simulations of Galactic Discs: Violent Feedback from Clustered Supernovae during Bursts of Star FormationAuthors: Davide MartizziComments: 17 pages, accepted by MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [72] arXiv:1908.04778 (replaced) [pdf, other]
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Title: Quasi-simultaneous radio and X-ray observations of Aql X-1: probing low luminositiesAuthors: N.V. Gusinskaia, J.W.T. Hessels, N. Degenaar, A.T. Deller, J.C.A. Miller-Jones, A.M. Archibald, C. O. Heinke, J. Moldon, A. Patruno, J. A. Tomsick, R. WijnandsComments: 15 pages, 11 figures, 3 tables, accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [73] arXiv:1908.05337 (replaced) [pdf, other]
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Title: Quantum Cosmology with many fluids and the choice of cosmological timeAuthors: G. A. Monerat, C. G. M. Santos, F. G. Alvarenga, S. V. B. Gonçalves, R. Fracalossi, E. V. Corrêa Silva, G. Oliveira-NetoComments: 26 pages, 25 figures, 2 tablesJournal-ref: Brazilian Journal of Physics, 2019Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [74] arXiv:1908.08876 (replaced) [pdf, other]
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Title: On a possible nonequilibrium imprint in the cosmic background at low frequenciesAuthors: Marco Baiesi, Carlo Burigana, Livia Conti, Gianmaria Falasco, Christian Maes, Lamberto Rondoni, Tiziana TrombettiComments: 31 pages, 3 figures, 1 table; Fig. 1 changed, Fig. 3 added, Sec. IV added, new references added, abstract changedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Statistical Mechanics (cond-mat.stat-mech)
- [75] arXiv:1908.10883 (replaced) [pdf, other]
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Title: Hubble Space Telescope Observations of Mira Variables in the Type Ia Supernova Host NGC 1559: An Alternative Candle to Measure the Hubble ConstantAuthors: Caroline D. Huang, Adam G. Riess, Wenlong Yuan, Lucas M. Macri, Nadia L. Zakamska, Stefano Casertano, Patricia A. Whitelock, Samantha L. Hoffmann, Alexei V. Filippenko, Daniel ScolnicComments: 15 pages, 11 figures, ApJ in pressSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Solar and Stellar Astrophysics (astro-ph.SR)
- [76] arXiv:1909.08484 (replaced) [pdf, other]
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Title: Cosmic-ray acceleration and escape from post-adiabatic Supernova remnantsComments: 12 pages, 13 figures, accepted by A&ASubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [77] arXiv:1910.06074 (replaced) [pdf, ps, other]
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Title: Magnetic helicity dissipation and production in an ideal MHD codeComments: 9 pages, 14 figures, 2 tables, ApJ (in press)Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); Fluid Dynamics (physics.flu-dyn)
- [78] arXiv:1910.06414 (replaced) [pdf, other]
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Title: Exporting Terrestrial Life Out of the Solar System with Gravitational Slingshots of Earthgrazing BodiesComments: 5 pages, 2 figures; accepted for publication in the International Journal of AstrobiologySubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [79] arXiv:1910.07573 (replaced) [pdf, other]
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Title: Resilient habitability of nearby exoplanet systemsComments: 17 pages, 15 figures, accepted for publication in MNRAS, 2019, Dec. 2Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [80] arXiv:1910.08417 (replaced) [pdf, other]
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Title: Predicting fully self-consistent satellite richness, galaxy growth and starformation rates from the STastical sEmi-Empirical modeL STEELComments: 21 PagesJournal-ref: MNRAS, Volume 491, Issue 1, January 2020, Pages 634-654Subjects: Astrophysics of Galaxies (astro-ph.GA)
- [81] arXiv:1910.13594 (replaced) [pdf, other]
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Title: The MOSDEF Survey: [SIII] as a New Probe of Evolving ISM ConditionsAuthors: Ryan L. Sanders, Tucker Jones, Alice E. Shapley, Naveen A. Reddy, Mariska Kriek, Alison L. Coil, Brian Siana, Bahram Mobasher, Irene Shivaei, Sedona H. Price, William R. Freeman, Mojegan Azadi, Gene C. K. Leung, Tara Fetherolf, Tom O. Zick, Laura de Groot, Guillermo Barro, Francesca M. FornasiniComments: 6 pages, 4 figures, accepted for publication in ApJ LettersSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [82] arXiv:1911.05039 (replaced) [pdf, other]
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Title: Helium abundance (and $H_0$) in X-COP galaxy clustersComments: 7 pages. To appear as proceedings article for the XMM-Newton Workshop "Astrophysics of Hot Plasma in Extended X-ray Sources" held at European Space Astronomy Centre, Madrid, Spain, on 12-14 June 2019Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [83] arXiv:1911.06776 (replaced) [pdf, ps, other]
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Title: 36 GHz methanol lines from nearby galaxies: maser or quasi-thermal emission?Authors: P. Humire, C. Henkel, Y. Gong, S. Leurini, R. Mauersberger, S.A. Levshakov, B. Winkel, A. Tarchi, P. Castangia, A. Malawi, H. Asiri, S.P. Ellingsen, T.P. McCarthy, X. Chen, X. TangComments: Accepted by Astronomy & Astrophysics, 8 pages, 1 table, 3 figures, slight changes w.r.t. version 1 due to language editingSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [84] arXiv:1911.09828 (replaced) [pdf, ps, other]
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Title: Spectral Classification and Ionized Gas Outflows in $z\sim2$ WISE-Selected Hot Dust-Obscured GalaxiesAuthors: Hyunsung D. Jun, Roberto J. Assef, Franz E. Bauer, Andrew W. Blain, Tanio Diaz-Santos, Peter R. Eisenhardt, Daniel Stern, Chao-Wei Tsai, Edward L. Wright, Jingwen WuComments: 20 pages, accepted to ApJ, minor corrections (typos and references) in section 4.4Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)
- [85] arXiv:1912.00375 (replaced) [pdf, other]
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Title: Physical Implications of the Sub-threshold GRB GBM-190816 and its Associated Sub-threshold Gravitational Wave EventAuthors: Yi-Si Yang, Shu-Qing Zhong, Bin-Bin Zhang, Shichao Wu, Bing Zhang, Yu-Han Yang, Zhoujian Cao, He Gao, Jin-Hang Zou, Jie-Shuang Wang, Hou-Jun Lü, Ji-Rong Cang, Zi-Gao DaiComments: 22 pages, 11 figures. Submitted to ApJLSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
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