RAS_WEB (Page 2,253)

Survival times of supramassive neutron stars resulting from binary neutron star mergers. (arXiv:2104.01181v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Beniamini_P/0/1/0/all/0/1">Paz Beniamini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lu_W/0/1/0/all/0/1">Wenbin Lu</a> A binary neutron star (BNS) merger can lead to various outcomes, from indefinitely stable neutron stars, through supramassive (SMNS) or hypermassive (HMNS) neutron stars supported only temporarily against gravity, to black holes formed promptly after the merger. Up-to-date constraints on the BNS total mass and the neutron star equation of state suggest that a long-lived SMNS may form in $sim 0.45-0.9$ of BNS mergers. We find that a SMNS typically needs to lose $sim 3-6times 10^{52}$ erg of it’s rotational energy before it collapses, onRead More →

Neutron Stars in Scalar-tensor Gravity with Higgs Scalar Potential. (arXiv:2104.01982v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Odintsov_S/0/1/0/all/0/1">S.D. Odintsov</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Oikonomou_V/0/1/0/all/0/1">V.K. Oikonomou</a> The Higgs scalar which is the only experimentally verified fundamental cosmological scalar, is also known to produce a viable inflationary phenomenology. In this work we investigate the effects of the Higgs model on static neutron stars. Particularly we derive the Einstein frame Tolman-Oppenheimer-Volkoff equations, and by numerically integrating them for both the interior and the exterior of the neutron star, using a double shooting python 3 based numerical code, we extract the masses and radii of the neutron stars, along with the several other related physical quantities ofRead More →

The Clustering of DESI-like Luminous Red Galaxies Using Photometric Redshifts. (arXiv:2001.06018v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_R/0/1/0/all/0/1">Rongpu Zhou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Newman_J/0/1/0/all/0/1">Jeffrey A. Newman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mao_Y/0/1/0/all/0/1">Yao-Yuan Mao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Meisner_A/0/1/0/all/0/1">Aaron Meisner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moustakas_J/0/1/0/all/0/1">John Moustakas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Myers_A/0/1/0/all/0/1">Adam D. Myers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Prakash_A/0/1/0/all/0/1">Abhishek Prakash</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zentner_A/0/1/0/all/0/1">Andrew R. Zentner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brooks_D/0/1/0/all/0/1">David Brooks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Duan_Y/0/1/0/all/0/1">Yutong Duan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Landriau_M/0/1/0/all/0/1">Martin Landriau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Levi_M/0/1/0/all/0/1">Michael E. Levi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Prada_F/0/1/0/all/0/1">Francisco Prada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tarle_G/0/1/0/all/0/1">Gregory Tarle</a> We present measurements of the redshift-dependent clustering of a DESI-like luminous red galaxy (LRG) sample selected from the Legacy Survey imaging dataset, and use the halo occupation distribution (HOD) framework to fit the clustering signal. The photometric LRG sample in this study contains 2.7 million objectsRead More →

The probability distribution of 3-D shapes of galaxy clusters from 2-D X-ray images. (arXiv:1908.04454v3 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Shankar_S/0/1/0/all/0/1">Swapnil Shankar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Khatri_R/0/1/0/all/0/1">Rishi Khatri</a> We present a new method to determine the probability distribution of the 3-D shapes of galaxy clusters from the 2-D images using stereology. In contrast to the conventional approach of combining different data sets (such as X-rays, Sunyaev-Zeldovich effect and lensing) to fit a 3-D model of a galaxy cluster for each cluster, our method requires only a single data set, such as X-ray observations or Sunyaev-Zeldovich effect observations, consisting of sufficiently large number of clusters. Instead of reconstructing the 3-D shape ofRead More →

NANOGrav and PPTA Tension: Gravity Waves, Cosmic Strings, and Inflation. (arXiv:2104.02016v1 [hep-ph]) <a href="http://arxiv.org/find/hep-ph/1/au:+Lazarides_G/0/1/0/all/0/1">George Lazarides</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Maji_R/0/1/0/all/0/1">Rinku Maji</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Shafi_Q/0/1/0/all/0/1">Qaisar Shafi</a> The NANOGrav collaboration has recently presented its pulsar timing array data which seem compatible with the presence of a stochastic gravity wave background emitted by cosmic strings with a dimensionless string tension $Gmusimeq 2times 10^{-11}-3times 10^{-10}$ at $95%$ confidence level ($G$ is Newton’s constant and $mu$ denotes the string tension). However, there is some tension between these results and the previous pulsar timing array bound $Gmulesssim 4times 10^{-11}$ from the PPTA experiment. We propose a relaxation of this tension by invoking primordial inflation whichRead More →

Chromospheric Heating by MHD Waves and Instabilities. (arXiv:2104.02010v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Srivastava_A/0/1/0/all/0/1">A.K. Srivastava</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ballester_J/0/1/0/all/0/1">J.L. Ballester</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cally_P/0/1/0/all/0/1">P.S. Cally</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carlsson_M/0/1/0/all/0/1">M. Carlsson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Goossens_M/0/1/0/all/0/1">M. Goossens</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jess_D/0/1/0/all/0/1">D.B. Jess</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Khomenko_E/0/1/0/all/0/1">E. Khomenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mathioudakis_M/0/1/0/all/0/1">M. Mathioudakis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Murawski_K/0/1/0/all/0/1">K. Murawski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zaqarashvili_T/0/1/0/all/0/1">T.V. Zaqarashvili</a> The importance of the chromosphere in the mass and energy transport within the solar atmosphere is now widely recognised. This review discusses the physics of magnetohydrodynamic (MHD) waves and instabilities in large-scale chromospheric structures as well as in magnetic flux tubes. We highlight a number of key observational aspects that have helped our understanding of the role of the solar chromosphere in various dynamic processes andRead More →

Constraining the origin of the puzzling source HESS J1640-465 and the PeVatron candidate HESS J1641-463 using Fermi-LAT observations. (arXiv:2104.02001v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Mares_A/0/1/0/all/0/1">A. Mares</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lemoine_Goumard_M/0/1/0/all/0/1">M. Lemoine-Goumard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Acero_F/0/1/0/all/0/1">F. Acero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clark_C/0/1/0/all/0/1">C. J. Clark</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Devin_J/0/1/0/all/0/1">J. Devin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gabici_S/0/1/0/all/0/1">S. Gabici</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gelfand_J/0/1/0/all/0/1">J. D. Gelfand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Green_D/0/1/0/all/0/1">D. A. Green</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grondin_M/0/1/0/all/0/1">M.-H. Grondin</a> There are only few very-high-energy sources in our Galaxy which might accelerate particles up to the knee of the cosmic-ray spectrum. To understand the mechanisms of particle acceleration in these PeVatron candidates, textit{Fermi}-LAT and H.E.S.S. observations are essential to characterize their $gamma$-ray emission. HESS J1640$-$465 and the PeVatron candidate HESS J1641$-$463 are two neighboring (ang[astroang]{0.25})Read More →

The HI and stellar mass bivariate distribution of centrals and satellites for all, late- and early-type local galaxies. (arXiv:2104.01983v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Calette_A/0/1/0/all/0/1">A. R. Calette</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Avila_Reese_V/0/1/0/all/0/1">Vladimir Avila-Reese</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Rodriguez_Puebla_A/0/1/0/all/0/1">Aldo Rodr&#xed;guez-Puebla</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Lagos_C/0/1/0/all/0/1">Claudia del P. Lagos</a> (2 and 3), <a href="http://arxiv.org/find/astro-ph/1/au:+Catinella_B/0/1/0/all/0/1">Barbara Catinella</a> (2 and 3) ((1) Instituto de Astronom&#xed;a, Universidad Nacional Aut&#xf3;noma de M&#xe9;xico, (2) International Centre for Radio Astronomy Research (ICRAR), University of Western Australia (3) ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)) We characterise the conditional distributions of the HI gas-to-stellar mass ratio, $R_{HI}equiv M_{HI}/M_{ast}$, given the stellar mass, $M_{ast}$, of local galaxies from $M_{ast}simRead More →

Warm Jupiters in TESS Full-Frame Images: A Catalog and Observed Eccentricity Distribution for Year 1. (arXiv:2104.01970v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Dong_J/0/1/0/all/0/1">Jiayin Dong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Huang_C/0/1/0/all/0/1">Chelsea X. Huang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dawson_R/0/1/0/all/0/1">Rebekah I. Dawson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Foreman_Mackey_D/0/1/0/all/0/1">Daniel Foreman-Mackey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Collins_K/0/1/0/all/0/1">Karen A. Collins</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Quinn_S/0/1/0/all/0/1">Samuel N. Quinn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lissauer_J/0/1/0/all/0/1">Jack J. Lissauer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beatty_T/0/1/0/all/0/1">Thomas G. Beatty</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Quarles_B/0/1/0/all/0/1">Billy Quarles</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sha_L/0/1/0/all/0/1">Lizhou Sha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shporer_A/0/1/0/all/0/1">Avi Shporer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guo_Z/0/1/0/all/0/1">Zhao Guo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kane_S/0/1/0/all/0/1">Stephen R. Kane</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Abe_L/0/1/0/all/0/1">Lyu Abe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barkaoui_K/0/1/0/all/0/1">Khalid Barkaoui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Benkhaldoun_Z/0/1/0/all/0/1">Zouhair Benkhaldoun</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brahm_R/0/1/0/all/0/1">Rafael A. Brahm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bouchy_F/0/1/0/all/0/1">Francois Bouchy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carmichael_T/0/1/0/all/0/1">Theron W. Carmichael</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Collins_K/0/1/0/all/0/1">Kevin I. Collins</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Conti_D/0/1/0/all/0/1">Dennis M. Conti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crouzet_N/0/1/0/all/0/1">Nicolas Crouzet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dransfield_G/0/1/0/all/0/1">Georgina Dransfield</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Evans_P/0/1/0/all/0/1">Phil Evans</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gan_T/0/1/0/all/0/1">Tianjun Gan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ghachoui_M/0/1/0/all/0/1">MouradRead More →

Simulation study on the effects of diffractive collisions on the prediction of the observables in ultra-high-energy cosmic ray experiments. (arXiv:2005.12594v3 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Ohashi_K/0/1/0/all/0/1">Ken Ohashi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Menjo_H/0/1/0/all/0/1">Hiroaki Menjo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Itow_Y/0/1/0/all/0/1">Yoshitaka Itow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sako_T/0/1/0/all/0/1">Takashi Sako</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kasahara_K/0/1/0/all/0/1">Katsuaki Kasahara</a> The mass composition of ultra-high-energy cosmic rays is important for understanding their origin. Owing to our limited knowledge of the hadronic interaction, the interpretations of the mass composition from observations include several open problems, such as the inconsistent interpretations of $langle X_{mathrm{max}}rangle $ and $langle X_{mathrm{max}}^{mu}rangle $. Futhermore, the large difference between the predictions exists by the hadronic interaction models. Diffractive collision is one of the proposed sourcesRead More →

Why Primordial Non-Gaussianity is Very Small?. (arXiv:2104.01953v1 [hep-th]) <a href="http://arxiv.org/find/hep-th/1/au:+Kristiano_J/0/1/0/all/0/1">J. Kristiano</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Yokoyama_J/0/1/0/all/0/1">Jun&#x27;ichi Yokoyama</a> One-loop correction to the power spectrum in generic single-field inflation is calculated extracting the most important operator, which also generates primordial non-Gaussianity, using soft effective field theory. Due to the enhancement inversely proportional to the observed red-tilt of the spectral index of curvature perturbation, the correction turns out to be much larger than previously anticipated. As a result, the primordial non-Gaussianity must be much smaller than the current observational bound in order to warrant the validity of cosmological perturbation theory. One-loop correction to the power spectrum in generic single-field inflation isRead More →

Improved cosmological fits with quantized primordial power spectra. (arXiv:2104.01938v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Bartlett_D/0/1/0/all/0/1">D. J. Bartlett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Handley_W/0/1/0/all/0/1">W. J. Handley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lasenby_A/0/1/0/all/0/1">A. N. Lasenby</a> We observationally examine cosmological models based on primordial power spectra with quantized wavevectors. Introducing a linearly quantized power spectrum with $k_0=3.225times10^{-4}mathrm{Mpc}^{-1}$ and spacing $Delta k = 2.257 times 10^{-4} mathrm{Mpc}^{-1}$ provides a better fit to the Planck 2018 observations than the concordance baseline, with $Delta chi^2 = -8.55$. Extending the results of Lasenby et al [1], we show that the requirement for perturbations to remain finite beyond the future conformal boundary in a universe containing dark matter and a cosmological constant results inRead More →

Power coupling losses for misaligned and mode-mismatched higher-order Hermite-Gauss modes. (arXiv:2104.01934v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Tao_L/0/1/0/all/0/1">Liu Tao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kelley_Derzon_J/0/1/0/all/0/1">Jessica Kelley-Derzon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Green_A/0/1/0/all/0/1">Anna C. Green</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fulda_P/0/1/0/all/0/1">Paul Fulda</a> This paper analytically and numerically investigates misalignment and mode-mismatch induced power coupling coefficients and losses as a function of Hermite Gauss (HG) mode order. We show that higher-order HG modes are more susceptible to beam perturbations: the misalignment and mode-mismatch induced power coupling losses scale linearly and quadratically with respect to the mode indices respectively. As a result, the mode-mismatch-limited tolerance for $mathrm{HG}_{3,3}$ mode for example is reduced to a factor of 0.28 compared against the currently-used fundamental Gaussian laserRead More →

The Phosphene Controversy: Is it Phosphene? Is there life on Venus?. (arXiv:2104.01932v1 [physics.pop-ph]) <a href="http://arxiv.org/find/physics/1/au:+Hasan_P/0/1/0/all/0/1">Priya Hasan</a> On 14th September 2020, the Royal Astronomical Society made an official statement coupled with a webminar on the discovery of phosphine on Venus. Single-line millimetre-waveband spectral detections of phosphine (with a signal-to-noise ratio of $approx$ 15$sigma$) from the JCMT and ALMA telescopes indicated a phosphine abundance of 20 ppb (parts per billion), 1000 times more than that on the Earth. Phosphine is an important biomarker and immediate speculation in the media about indicators of life being found on Venus followed. This article presents an analysis of the study andRead More →

Can dark energy be dynamical?. (arXiv:2104.01930v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Colgain_E/0/1/0/all/0/1">Eoin &#xd3; Colg&#xe1;in</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sheikh_Jabbari_M/0/1/0/all/0/1">M. M. Sheikh-Jabbari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yin_L/0/1/0/all/0/1">Lu Yin</a> We highlight shortcomings of the dynamical dark energy (DDE) paradigm. For parametric models with equation of state (EOS), $w(z) = w_0 + w_a f(z)$ for a given function of redshift $f(z)$, we show that the errors in $w_a$ are sensitive to $f(z)$: if $f(z)$ increases quickly with redshift $z$, then errors in $w_a$ are smaller, and vice versa. As a result, parametric DDE models suffer from a degree of arbitrariness and focusing too much on one model runs that risk that DDE may be overlooked. In particular,Read More →

Fast radio bursts and their high-energy counterpart from magnetar magnetospheres. (arXiv:2104.01925v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_Y/0/1/0/all/0/1">Yuan-Pei Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_B/0/1/0/all/0/1">Bing Zhang</a> The recent discovery of a Galactic fast radio burst (FRB) occurring simultaneously with an X-ray burst (XRB) from the Galactic magnetar SGR J1935+2154 implies that at least some FRBs arise from magnetar activities. We propose that FRBs are triggered by crust fracturing of magnetars, with the burst event rate depending on the magnetic field strength in the crust. Crust fracturing produces Alfv’en waves, forming a charge starved region in the magnetosphere and leading to non-stationary pair plasma discharges. An FRB is produced by coherent plasma emission dueRead More →

From Lacaille to Lalande. French works on lunar distances, nautical ephemerides and lunar tables, 1742-1785. (arXiv:2104.01916v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Boistel_G/0/1/0/all/0/1">Guy Boistel</a> The papers studies the highly misknown works of french astronomers on ephemerides and lunar distances on the period 1742-1785. These works will have a strong influence on the development of the Nautical Almanac by Nevil Maskelyne in 1766-1767. The papers studies the highly misknown works of french astronomers on ephemerides and lunar distances on the period 1742-1785. These works will have a strong influence on the development of the Nautical Almanac by Nevil Maskelyne in 1766-1767. http://arxiv.org/icons/sfx.gifRead More →

Non-minimally coupled curvaton. (arXiv:2005.11069v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_L/0/1/0/all/0/1">Lei-Hua Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Prokopec_T/0/1/0/all/0/1">Tomislav Prokopec</a> We investigate two-field inflationary models in which scalar cosmological pertubations are generated via a spectator field nonminimally coupled to gravity, with the particular emphasis on curvaton scenarios. The principal advantage of these models is in the possibility to tune the spectator spectral index via the nonminimal coupling. Our models naturally yield red spectrum of the adiabatic perturbation demanded by observations. We study how the nonminimal coupling affects the spectrum of the curvature perturbation generated in the curvaton scenarios. In particular we find that for small, negative nonminimal couplings the spectral index gets aRead More →