New cataclysmic variable star discovered Using NASA’s Kepler spacecraft, astronomers have detected a new bright transient event. After further analysis, the newly found transient source turned out to be a cataclysmic variable (CV) star. The finding is detailed in a paper published August 10 on the arXiv pre-print server. phys.org Go to SourceRead More →
Robotic telescope finds closest known asteroid to fly by Earth On August 16, the Zwicky Transient Facility (ZTF), a robotic survey camera located at Palomar Observatory near San Diego, spotted an asteroid that had, just hours earlier, traveled only 1,830 miles (2,950 kilometers) above Earth’s surface. Designated 2020 QG, it is the closest known asteroid to fly by Earth without impacting the planet. The previous known record-holder is asteroid 2011 CQ1, discovered by the Catalina Sky Survey in 2011, which passed above Earth about 1,550 miles (2,500 kilometers) higher than 2020 QG. phys.org Go to SourceRead More →
A dusty origin for the correlation between protoplanetary disc accretion rates and dust masses. (arXiv:2008.07530v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Sellek_A/0/1/0/all/0/1">Andrew D. Sellek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Booth_R/0/1/0/all/0/1">Richard A. Booth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clarke_C/0/1/0/all/0/1">Cathie J. Clarke</a> Recent observations have uncovered a correlation between the accretion rates (measured from the UV continuum excess) of protoplanetary discs and their masses inferred from observations of the sub-mm continuum. While viscous evolution models predict such a correlation, the predicted values are in tension with data obtained from the Lupus and Upper Scorpius star forming regions; for example, they underpredict the scatter in accretion rates, particularly in older regions. Here we argue that since the sub-mm observations traceRead More →
Gravitomagnetic tidal resonance in neutron-star binary inspirals. (arXiv:2003.10427v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Poisson_E/0/1/0/all/0/1">Eric Poisson</a> A compact binary system implicating at least one rotating neutron star undergoes gravitomagnetic tidal resonances as it inspirals toward its final merger. These have a dynamical impact on the phasing of the emitted gravitational waves. The resonances are produced by the inertial modes of vibration of the rotating star. Four distinct modes are involved, and the resonances occur within the frequency band of interferometric gravitational-wave detectors when the star spins at a frequency that lies within this band. The resonances are driven by the gravitomagnetic tidal field created by the companion star;Read More →
The gas production of 14 species from comet 67P/Churyumov-Gerasimenko based on DFMS/COPS data from 2014-2016. (arXiv:2006.01750v3 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Laeuter_M/0/1/0/all/0/1">Matthias Laeuter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kramer_T/0/1/0/all/0/1">Tobias Kramer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rubin_M/0/1/0/all/0/1">Martin Rubin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Altwegg_K/0/1/0/all/0/1">Kathrin Altwegg</a> The coma of comet 67P/Churyumov-Gerasimenko has been probed by the Rosetta spacecraft and shows a variety of different molecules. The ROSINA COmet Pressure Sensor and the Double Focusing Mass Spectrometer provide in-situ densities for many volatile compounds including the 14 gas species H2O, CO2, CO, H2S, O2, C2H6, CH3OH, H2CO, CH4, NH3, HCN, C2H5OH, OCS, and CS2. We fit the observed densities during the entire comet mission between August 2014 and September 2016 to anRead More →
Core-Collapse Supernovae in Binaries as the Origin of Galactic Hyper-Runaway Stars. (arXiv:2006.00849v2 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Evans_F/0/1/0/all/0/1">Fraser A. Evans</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Renzo_M/0/1/0/all/0/1">Mathieu Renzo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rossi_E/0/1/0/all/0/1">Elena Maria Rossi</a> Several stars detected moving at velocities near to or exceeding the Galactic escape speed likely originated in the Milky Way disc. We quantitatively explore the `binary supernova scenario’ hypothesis, wherein these `hyper-runaway’ stars are ejected at large peculiar velocities when their close, massive binary companions undergo a core-collapse supernova and the binary is disrupted. We perform an extensive suite of binary population synthesis simulations evolving massive systems to determine the assumptions and parameters which most impact the ejection rate ofRead More →
A hierarchical field-level inference approach to reconstruction from sparse Lyman-$alpha$ forest data. (arXiv:2005.12928v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Porqueres_N/0/1/0/all/0/1">Natalia Porqueres</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hahn_O/0/1/0/all/0/1">Oliver Hahn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jasche_J/0/1/0/all/0/1">Jens Jasche</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lavaux_G/0/1/0/all/0/1">Guilhem Lavaux</a> We address the problem of inferring the three-dimensional matter distribution from a sparse set of one-dimensional quasar absorption spectra of the Lyman-$alpha$ forest. Using a Bayesian forward modelling approach, we focus on extending the dynamical model to a fully self-consistent hierarchical field-level prediction of redshift-space quasar absorption sightlines. Our field-level approach rests on a recently developed semiclassical analogue to Lagrangian perturbation theory (LPT), which improves over noise problems and interpolation requirements of LPT. It furthermore allows for aRead More →
Resolving small-scale cold circumgalactic gas in TNG50. (arXiv:2005.09654v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Nelson_D/0/1/0/all/0/1">Dylan Nelson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sharma_P/0/1/0/all/0/1">Prateek Sharma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pillepich_A/0/1/0/all/0/1">Annalisa Pillepich</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Springel_V/0/1/0/all/0/1">Volker Springel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pakmor_R/0/1/0/all/0/1">Ruediger Pakmor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weinberger_R/0/1/0/all/0/1">Rainer Weinberger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vogelsberger_M/0/1/0/all/0/1">Mark Vogelsberger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marinacci_F/0/1/0/all/0/1">Federico Marinacci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hernquist_L/0/1/0/all/0/1">Lars Hernquist</a> We use the high-resolution TNG50 cosmological magnetohydrodynamical simulation to explore the properties and origin of cold circumgalactic medium (CGM) gas around massive galaxies (M* > 10^11 Msun) at intermediate redshift (z~0.5). We discover a significant abundance of small-scale, cold gas structure in the CGM of ‘red and dead’ elliptical systems, as traced by neutral HI and MgII. Halos can host tens of thousands of discrete absorbing cloudlets, withRead More →
The Predicted Properties of Helium-Enriched Globular Cluster Progenitors at High Redshift. (arXiv:2005.06488v2 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Nataf_D/0/1/0/all/0/1">David M. Nataf</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Horiuchi_S/0/1/0/all/0/1">Shunsaku Horiuchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Costa_G/0/1/0/all/0/1">Guglielmo Costa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wyse_R/0/1/0/all/0/1">Rosemary F. G. Wyse</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ting_Y/0/1/0/all/0/1">Yuan-Sen Ting</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crocker_R/0/1/0/all/0/1">Roland Crocker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Federrath_C/0/1/0/all/0/1">Christoph Federrath</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_Y/0/1/0/all/0/1">Yang Chen</a> Globular cluster progenitors may have been detected by textit{HST}, and are predicted to be observable with textit{JWST} and ground-based extremely-large telescopes with adaptive optics. This has the potential to elucidate the issue of globular cluster formation and the origins of significantly helium-enriched subpopulations, a problem in Galactic astronomy with no satisfactory theoretical solution. Given this context, we use model stellar tracks and isochrones toRead More →
Six pieces of evidence against the corotation enforcement theory to explain the main aurora at Jupiter. (arXiv:2005.05938v2 [physics.space-ph] UPDATED) <a href="http://arxiv.org/find/physics/1/au:+Bonfond_B/0/1/0/all/0/1">Bertrand Bonfond</a>, <a href="http://arxiv.org/find/physics/1/au:+Yao_Z/0/1/0/all/0/1">Zhonghua Yao</a>, <a href="http://arxiv.org/find/physics/1/au:+Grodent_D/0/1/0/all/0/1">Denis Grodent</a> The most remarkable feature of the ultraviolet auroras at Jupiter is the ever present and almost continuous curtain of bright emissions centered on each magnetic pole and called the main emissions. According to the classical theory, it results from an electric current loop transferring momentum from the Jovian ionosphere to the magnetospheric plasma. However, predictions based on these mainstream models have been recently challenged by observations from Juno and the Hubble Space Telescope. Here we review theRead More →
Revisiting supernova constraints on a light CP-even scalar. (arXiv:2005.00490v2 [hep-ph] UPDATED) <a href="http://arxiv.org/find/hep-ph/1/au:+Dev_P/0/1/0/all/0/1">P. S. Bhupal Dev</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Mohapatra_R/0/1/0/all/0/1">Rabindra N. Mohapatra</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Zhang_Y/0/1/0/all/0/1">Yongchao Zhang</a> A light CP-even Standard Model (SM) gauge-singlet scalar $S$ can be produced abundantly in the supernova core, via the nucleon bremsstrahlung process $N N to N N S$, due to its mixing with the SM Higgs boson. Including the effective $S$ coupling to both nucleons and the pion mediators, we evaluate the production amplitude for the $S$ particle and point out a key difference with the well-known light CP-odd scalar (axion) and vector boson (dark photon) cases. Taking the subsequent decay andRead More →
Localizing merging black holes with sub-arcsecond precision using gravitational-wave lensing. (arXiv:2004.13811v3 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Hannuksela_O/0/1/0/all/0/1">Otto A. Hannuksela</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Collett_T/0/1/0/all/0/1">Thomas E. Collett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Caliskan_M/0/1/0/all/0/1">Mesut Çalışkan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_T/0/1/0/all/0/1">Tjonnie G. F. Li</a> The current gravitational-wave localization methods rely mainly on sources with electromagnetic counterparts. Unfortunately, a binary black hole does not emit light. Due to this, it is generally not possible to localize these objects precisely. However, strongly lensed gravitational waves, which are forecasted in this decade, could allow us to localize the binary by locating its lensed host galaxy. Identifying the correct host galaxy is challenging because there are hundreds to thousands of other lensed galaxies withinRead More →
Fitting string inflation to real cosmological data: the Fibre Inflation case. (arXiv:2004.01210v3 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Cicoli_M/0/1/0/all/0/1">Michele Cicoli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Valentino_E/0/1/0/all/0/1">Eleonora Di Valentino</a> In this paper we show how the string landscape can be constrained using observational data. We illustrate this idea by focusing on Fibre Inflation which is a promising class of string inflationary models in type IIB flux compactifications. We determine the values of the microscopic flux-dependent parameters which yield the best fit to the most recent cosmological datasets. In this paper we show how the string landscape can be constrained using observational data. We illustrate this idea by focusing on Fibre Inflation which isRead More →
Constraints on Primordial Black Holes: the Importance of Accretion. (arXiv:2003.12589v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Luca_V/0/1/0/all/0/1">V. De Luca</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Franciolini_G/0/1/0/all/0/1">G. Franciolini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pani_P/0/1/0/all/0/1">P. Pani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Riotto_A/0/1/0/all/0/1">A. Riotto</a> We consider the constraints on the fraction of dark matter in the universe in the form of primordial black holes taking into account the crucial role of accretion which may change both their mass and mass function. We show that accretion may drastically weaken the constraints at the present epoch for primordial black holes with masses larger than a few solar masses. We consider the constraints on the fraction of dark matter in the universe in the form of primordialRead More →
Stress-driven spin-down of a viscous fluid within a spherical shell. (arXiv:2003.10403v2 [physics.flu-dyn] UPDATED) <a href="http://arxiv.org/find/physics/1/au:+Gagnier_D/0/1/0/all/0/1">Damien Gagnier</a>, <a href="http://arxiv.org/find/physics/1/au:+Rieutord_M/0/1/0/all/0/1">Michel Rieutord</a> We investigate the linear properties of the steady and axisymmetric stress-driven spin-down flow of a viscous fluid inside a spherical shell, both within the incompressible and anelastic approximations, and in the asymptotic limit of small viscosities. From boundary layer analysis, we derive an analytical geostrophic solution for the 3D incompressible steady flow, inside and outside the cylinder $mathcal{C}$ that is tangent to the inner shell. The Stewartson layer that lies on $mathcal{C}$ is composed of two nested shear layers of thickness $O(E^{2/7})$ and $O(E^{1/3})$. We deriveRead More →
Alternative high plasma beta regimes of electron heat-flux instabilities in the solar wind. (arXiv:2006.04263v2 [physics.space-ph] UPDATED) <a href="http://arxiv.org/find/physics/1/au:+Lopez_R/0/1/0/all/0/1">R. A. López</a>, <a href="http://arxiv.org/find/physics/1/au:+Lazar_M/0/1/0/all/0/1">M. Lazar</a>, <a href="http://arxiv.org/find/physics/1/au:+Shaaban_S/0/1/0/all/0/1">S. M. Shaaban</a>, <a href="http://arxiv.org/find/physics/1/au:+Poedts_S/0/1/0/all/0/1">S. Poedts</a>, <a href="http://arxiv.org/find/physics/1/au:+Moya_P/0/1/0/all/0/1">P. S. Moya</a> The heat transport in the solar wind is dominated by the suprathermal electron populations, i.e., a tenuous halo and a field-aligned beam/strahl, with high energies and antisunward drifts along the magnetic field. Their evolution may offer plausible explanations for the rapid decrease of the heat flux with the solar wind expansion, typically invoked being the self-generated instabilities, or the so-called heat flux instabilities (HFIs). The present paper provides a unified descriptionRead More →
Prompt Accretion Disk Formation in an X-Ray Faint Tidal Disruption Event. (arXiv:2003.09427v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Hung_T/0/1/0/all/0/1">Tiara Hung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Foley_R/0/1/0/all/0/1">Ryan J. Foley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ramirez_Ruiz_E/0/1/0/all/0/1">Enrico Ramirez-Ruiz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dai_J/0/1/0/all/0/1">Jane L. Dai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Auchettl_K/0/1/0/all/0/1">Katie Auchettl</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kilpatrick_C/0/1/0/all/0/1">Charles D. Kilpatrick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mockler_B/0/1/0/all/0/1">Brenna Mockler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brown_J/0/1/0/all/0/1">Jonathan S. Brown</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coulter_D/0/1/0/all/0/1">David A. Coulter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dimitriadis_G/0/1/0/all/0/1">Georgios Dimitriadis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Holoien_T/0/1/0/all/0/1">Thomas W.-S. Holoien</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Law_Smith_J/0/1/0/all/0/1">Jamie A.P. Law-Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piro_A/0/1/0/all/0/1">Anthony L. Piro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rest_A/0/1/0/all/0/1">Armin Rest</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rojas_Bravo_C/0/1/0/all/0/1">César Rojas-Bravo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Siebert_M/0/1/0/all/0/1">Matthew R. Siebert</a> We present the multi-wavelength analysis of the tidal disruption event (TDE) AT~2018hyz (ASASSN-18zj). From follow-up optical spectroscopy, we detect the first unambiguous case of resolved double-peaked Balmer emission in a TDE. The distinct lineRead More →
Sun-Heliosphere Observation-based Ionization Rates Model. (arXiv:2003.09292v3 [physics.space-ph] UPDATED) <a href="http://arxiv.org/find/physics/1/au:+Soko%5Cl_J/0/1/0/all/0/1">Justyna M. Sokół</a>, <a href="http://arxiv.org/find/physics/1/au:+McComas_D/0/1/0/all/0/1">D. J. McComas</a>, <a href="http://arxiv.org/find/physics/1/au:+Bzowski_M/0/1/0/all/0/1">M. Bzowski</a>, <a href="http://arxiv.org/find/physics/1/au:+Tokumaru_M/0/1/0/all/0/1">M. Tokumaru</a> The solar wind (SW) and the extreme ultraviolet (EUV) radiation modulate fluxes of interstellar and heliospheric particles inside the heliosphere both in time and in space. Understanding this modulation is necessary to correctly interpret measurements of particles of interstellar origin inside the heliosphere. We present a revision of heliospheric ionization rates and provide the Sun-Heliosphere Observation-based Ionization Rates (SHOIR) model based on the currently available data. We calculate the total ionization rates using revised SW and solar EUV data. We study the in-eclipticRead More →
Observed binary populations reflect the Galactic history. Explaining the orbital period-mass ratio relation in wide hot subdwarf binaries. (arXiv:2003.05665v3 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Vos_J/0/1/0/all/0/1">Joris Vos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bobrick_A/0/1/0/all/0/1">Alexey Bobrick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vuckovic_M/0/1/0/all/0/1">Maja Vuckovic</a> Wide hot subdwarf B (sdB) binaries with main-sequence companions are outcomes of stable mass transfer from evolved red giants. The orbits of these binaries show a strong correlation between their orbital periods and mass ratios. The origins of this correlation have, so far, been lacking a conclusive explanation. We aim to find a binary evolution model which can explain the observed correlation. Radii of evolved red giants, and hence the resulting orbital periods, strongly dependRead More →
Enhanced spectrum of primordial perturbations, galaxy formation and small scale structure. (arXiv:2002.06656v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Seleim_K/0/1/0/all/0/1">Karim H. Seleim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+El_Zant_A/0/1/0/all/0/1">Amr A. El-Zant</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Abdel_Moneim_A/0/1/0/all/0/1">A. M. Abdel-Moneim</a> The standard structure formation scenario is successful on linear scales. Several apparent problems affect it however at galactic scales, such as the small scale problems at low redshift and more recent issues involving early massive galaxy and black hole formation. As these problems arise where complex baryonic physics becomes important, the associated unknowns are often assumed to be behind the problems. But the same scales are also those where the primordial spectrum is relatively unconstrained, and there are severalRead More →
