RAS_WEB (Page 2,676)

Evaluating Low-Frequency Pulsar Observations to Monitor Dispersion with the Giant Metrewave Radio Telescope. (arXiv:2009.08409v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Jones_M/0/1/0/all/0/1">Megan L. Jones</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McLaughlin_M/0/1/0/all/0/1">Maura A. McLaughlin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Roy_J/0/1/0/all/0/1">Jayanta Roy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lam_M/0/1/0/all/0/1">Michael T. Lam</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cordes_J/0/1/0/all/0/1">James M. Cordes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kaplan_D/0/1/0/all/0/1">David L. Kaplan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bhattacharyya_B/0/1/0/all/0/1">Bhaswati Bhattacharyya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Levin_L/0/1/0/all/0/1">Lina Levin</a> The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project has the primary goal of detecting and characterizing low-frequency gravitational waves through high-precision pulsar timing. The mitigation of interstellar effects is crucial to achieve the necessary precision for gravitational wave detection. Effects like dispersion and scattering are more influential at lower observing frequencies, with the variation of these quantities over week-monthRead More →

Solar Flare Energy Partitioning and Transport — the Gradual Phase (a Heliophysics 2050 White Paper). (arXiv:2009.08407v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Kerr_G/0/1/0/all/0/1">Graham S. Kerr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alaoui_M/0/1/0/all/0/1">Meriem Alaoui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Allred_J/0/1/0/all/0/1">Joel C. Allred</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bian_N/0/1/0/all/0/1">Nicholas H. Bian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dennis_B/0/1/0/all/0/1">Brian R. Dennis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Emslie_A/0/1/0/all/0/1">A. Gordon Emslie</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fletcher_L/0/1/0/all/0/1">Lyndsay Fletcher</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guidoni_S/0/1/0/all/0/1">Silvina Guidoni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hayes_L/0/1/0/all/0/1">Laura A. Hayes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Holman_G/0/1/0/all/0/1">Gordon D. Holman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hudson_H/0/1/0/all/0/1">Hugh S. Hudson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Karpen_J/0/1/0/all/0/1">Judith T. Karpen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kowalski_A/0/1/0/all/0/1">Adam F. Kowalski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Milligan_R/0/1/0/all/0/1">Ryan O. Milligan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Polito_V/0/1/0/all/0/1">Vanessa Polito</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Qiu_J/0/1/0/all/0/1">Jiong Qiu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ryan_D/0/1/0/all/0/1">Daniel F. Ryan</a> Solar flares are a fundamental component of solar eruptive events (SEEs; along with solar energetic particles, SEPs, and coronal mass ejections, CMEs). Flares are theRead More →

On the Absorption Properties of Metallic Needles. (arXiv:2009.08406v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Xiao_C/0/1/0/all/0/1">C.Y. Xiao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_Q/0/1/0/all/0/1">Qi Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_A/0/1/0/all/0/1">Aigen Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_J/0/1/0/all/0/1">J.H. Chen</a> Needle-like metallic particles have been suggested to explain a wide variety of astrophysical phenomena, ranging from the mid-infrared interstellar extinction to the thermalization of starlight to generate the cosmic microwave background. These suggestions rely on the amplitude and the wavelength dependence of the absorption cross sections of metallic needles. On the absence of an exact solution to the absorption properties of metallic needles, their absorption cross sections are often derived from the antenna approximation. However, it is shown here that the antenna approximation isRead More →

Deuterated Polycyclic Aromatic Hydrocarbons in the Interstellar Medium: The C–D Band Strengths of Mono-Deuterated Species. (arXiv:2009.08402v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_X/0/1/0/all/0/1">X.J. Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_A/0/1/0/all/0/1">Aigen Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Glaser_R/0/1/0/all/0/1">R. Glaser</a> Deuterium (D) is one of the light elements created in the big bang. As the Galaxy evolves, the D/H abundance in the interstellar medium (ISM) decreases from its primordial value due to “astration”. However, the observed gas-phase D/H abundances of some interstellar sightlines are substantially lower than the expected reduction by astration alone. The missing D could have been depleted onto polycyclic aromatic hydrocarbon (PAH) molecules which are ubiquitous and abundant in interstellar regions. To quantitatively explore the hypothesisRead More →

Solar Flare Energy Partitioning and Transport — the Impulsive Phase (a Heliophysics 2050 White Paper). (arXiv:2009.08400v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Kerr_G/0/1/0/all/0/1">Graham S. Kerr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alaoui_M/0/1/0/all/0/1">Meriem Alaoui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Allred_J/0/1/0/all/0/1">Joel C. Allred</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bian_N/0/1/0/all/0/1">Nicholas H. Bian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dennis_B/0/1/0/all/0/1">Brian R. Dennis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Emslie_A/0/1/0/all/0/1">A. Gordon Emslie</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fletcher_L/0/1/0/all/0/1">Lyndsay Fletcher</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guidoni_S/0/1/0/all/0/1">Silvina Guidoni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hayes_L/0/1/0/all/0/1">Laura A. Hayes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Holman_G/0/1/0/all/0/1">Gordon D. Holman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hudson_H/0/1/0/all/0/1">Hugh S. Hudson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Karpen_J/0/1/0/all/0/1">Judith T. Karpen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kowalski_A/0/1/0/all/0/1">Adam F. Kowalski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Milligan_R/0/1/0/all/0/1">Ryan O. Milligan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Polito_V/0/1/0/all/0/1">Vanessa Polito</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Qiu_J/0/1/0/all/0/1">Jiong Qiu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ryan_D/0/1/0/all/0/1">Daniel F. Ryan</a> Solar flares are a fundamental component of solar eruptive events (SEEs; along with solar energetic particles, SEPs, and coronal mass ejections, CMEs). Flares are theRead More →

High-energy gamma-ray study of the dynamically young SNR G150.3+4.5. (arXiv:2009.08397v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Devin_J/0/1/0/all/0/1">Justine Devin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lemoine_Goumard_M/0/1/0/all/0/1">Marianne Lemoine-Goumard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grondin_M/0/1/0/all/0/1">Marie-H&#xe9;l&#xe8;ne Grondin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Castro_D/0/1/0/all/0/1">Daniel Castro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ballet_J/0/1/0/all/0/1">Jean Ballet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cohen_J/0/1/0/all/0/1">Jamie Cohen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hewitt_J/0/1/0/all/0/1">John W. Hewitt</a> The supernova remnant (SNR) G150.3+4.5 was recently discovered in the radio band; it exhibits a shell-like morphology with an angular size of $sim 3^{circ}$, suggesting either an old or a nearby SNR. Extended $gamma$-ray emission spatially coincident with the SNR was reported in the Fermi Galactic Extended Source Catalog, with a power-law spectral index of $Gamma$ = 1.91 $pm$ 0.09. Studying particle acceleration in SNRs through their $gamma$-ray emission is of primaryRead More →

Feasibility Analysis and Preliminary Design of ChipSat Entry for In-situ Investigation of the Atmosphere of Venus. (arXiv:2009.08396v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Vivenzio_S/0/1/0/all/0/1">Salvatore Vivenzio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fries_D/0/1/0/all/0/1">Dan Fries</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Welch_C/0/1/0/all/0/1">Chris Welch</a> Recent miniaturization of electronics in very small, low-cost and low-power configurations suitable for use in spacecraft have inspired innovative small-scale satellite concepts, such as ChipSats, centimeter-scale satellites with a mass of a few grams. These extremely small spacecraft have the potential to usher in a new age of space science accessibility. Due to their low ballistic coefficient, ChipSats can potentially be used in a swarm constellation for extended surveys of planetary atmospheres, providing large amounts of data withRead More →

The EDGE-CALIFA survey: exploring the role of the molecular gas on the galaxy star formation quenching. (arXiv:2009.08383v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Colombo_D/0/1/0/all/0/1">D. Colombo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sanchez_S/0/1/0/all/0/1">S.F. Sanchez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bolatto_A/0/1/0/all/0/1">A. D. Bolatto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kalinova_V/0/1/0/all/0/1">V. Kalinova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weiss_A/0/1/0/all/0/1">A. Weiss</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wong_T/0/1/0/all/0/1">T. Wong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rosolowsky_E/0/1/0/all/0/1">E. Rosolowsky</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vogel_S/0/1/0/all/0/1">S. N. Vogel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barrera_Ballesteros_J/0/1/0/all/0/1">J. Barrera-Ballesteros</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dannerbauer_H/0/1/0/all/0/1">H. Dannerbauer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cao_Y/0/1/0/all/0/1">Y. Cao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Levy_R/0/1/0/all/0/1">R. C. Levy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Utomo_D/0/1/0/all/0/1">D. Utomo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blitz_L/0/1/0/all/0/1">L. Blitz</a> Understanding how galaxies cease to form stars represents an outstanding challenge for galaxy evolution theories. This process of “star formation quenching” has been related to various causes, including Active Galactic Nuclei (AGN) activity, the influence of large-scale dynamics, and the environment inRead More →

The Enigmatic Galactic Center Excess: Spurious Point Sources and Signal Mismodeling. (arXiv:2002.12371v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Leane_R/0/1/0/all/0/1">Rebecca K. Leane</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Slatyer_T/0/1/0/all/0/1">Tracy R. Slatyer</a> The Galactic Center GeV excess (GCE) has garnered great interest as a possible signal of either dark matter annihilation or some novel astrophysical phenomenon, such as a new population of gamma-ray emitting pulsars. In a companion paper, we showed that in a $10^circ$ radius region of interest (ROI) surrounding the Galactic Center, apparent evidence for GCE point sources (PSs) from non-Poissonian template fitting (NPTF) is actually an artifact of unmodeled north-south asymmetry of the GCE. In this work, we develop a simplified analyticRead More →

Bulk viscosity in relativistic fluids: from thermodynamics to hydrodynamics. (arXiv:2003.04609v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Gavassino_L/0/1/0/all/0/1">Lorenzo Gavassino</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Antonelli_M/0/1/0/all/0/1">Marco Antonelli</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Haskell_B/0/1/0/all/0/1">Brynmor Haskell</a> The approach of extended irreversible thermodynamics consists of promoting the dissipative fluxes to non-equilibrium thermodynamic variables. In a relativistic context, this naturally leads to the formulation of the theory of Israel and Stewart (1979), which is, to date, one of the most successful theories for relativistic dissipation. Although the generality of the principle makes it applicable to any dissipative fluid, a connection of the Israel-Stewart theory with microphysics has been established, through kinetic theory, only for the case of ideal quantum gases. By performingRead More →

A planetary system with two transiting mini-Neptunes near the radius valley transition around the bright M dwarf TOI-776. (arXiv:2009.08338v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Luque_R/0/1/0/all/0/1">R. Luque</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Serrano_L/0/1/0/all/0/1">L. M. Serrano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Molaverdikhani_K/0/1/0/all/0/1">K. Molaverdikhani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nixon_M/0/1/0/all/0/1">M. C. Nixon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Livingston_J/0/1/0/all/0/1">J. H. Livingston</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guenther_E/0/1/0/all/0/1">E. W. Guenther</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Palle_E/0/1/0/all/0/1">E. Pall&#xe9;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Madhusudhan_N/0/1/0/all/0/1">N. Madhusudhan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nowak_G/0/1/0/all/0/1">G. Nowak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Korth_J/0/1/0/all/0/1">J. Korth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cochran_W/0/1/0/all/0/1">W. D. Cochran</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hirano_T/0/1/0/all/0/1">T. Hirano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chaturvedi_P/0/1/0/all/0/1">P. Chaturvedi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Goffo_E/0/1/0/all/0/1">E. Goffo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Albrecht_S/0/1/0/all/0/1">S. Albrecht</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barragan_O/0/1/0/all/0/1">O. Barrag&#xe1;n</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Briceno_C/0/1/0/all/0/1">C Brice&#xf1;o</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cabrera_J/0/1/0/all/0/1">J. Cabrera</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Charbonneau_D/0/1/0/all/0/1">D. Charbonneau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cloutier_R/0/1/0/all/0/1">R. Cloutier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Collins_K/0/1/0/all/0/1">K. A. Collins</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Collins_K/0/1/0/all/0/1">K. I. Collins</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Colon_K/0/1/0/all/0/1">K. D. Col&#xf3;n</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crossfield_I/0/1/0/all/0/1">I. J. M. Crossfield</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Csizmadia_S/0/1/0/all/0/1">Sz. Csizmadia</a>,Read More →

The Saturn Ring Skimmer Mission Concept: The next step to explore Saturn’s rings, atmosphere, interior, and inner magnetosphere. (arXiv:2007.15767v2 [astro-ph.IM] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Tiscareno_M/0/1/0/all/0/1">Matthew S. Tiscareno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vaquero_M/0/1/0/all/0/1">Mar Vaquero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hedman_M/0/1/0/all/0/1">Matthew M. Hedman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cao_H/0/1/0/all/0/1">Hao Cao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Estrada_P/0/1/0/all/0/1">Paul R. Estrada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ingersoll_A/0/1/0/all/0/1">Andrew P. Ingersoll</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miller_K/0/1/0/all/0/1">Kelly E. Miller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parisi_M/0/1/0/all/0/1">Marzia Parisi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Atkinson_D/0/1/0/all/0/1">David. H. Atkinson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brooks_S/0/1/0/all/0/1">Shawn M. Brooks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cuzzi_J/0/1/0/all/0/1">Jeffrey N. Cuzzi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fuller_J/0/1/0/all/0/1">James Fuller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hendrix_A/0/1/0/all/0/1">Amanda R. Hendrix</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnson_R/0/1/0/all/0/1">Robert E. Johnson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koskinen_T/0/1/0/all/0/1">Tommi Koskinen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kurth_W/0/1/0/all/0/1">William S. Kurth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lunine_J/0/1/0/all/0/1">Jonathan I. Lunine</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nicholson_P/0/1/0/all/0/1">Philip D. Nicholson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paty_C/0/1/0/all/0/1">Carol S. Paty</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schindhelm_R/0/1/0/all/0/1">Rebecca Schindhelm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Showalter_M/0/1/0/all/0/1">Mark R. Showalter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Spilker_L/0/1/0/all/0/1">Linda J. Spilker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Strange_N/0/1/0/all/0/1">NathanRead More →

Revisiting the Architecture of the KOI-89 System. (arXiv:2009.06850v2 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Masuda_K/0/1/0/all/0/1">Kento Masuda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tamayo_D/0/1/0/all/0/1">Daniel Tamayo</a> While high stellar obliquities observed in exoplanetary systems may be attributed to processes that tilt the planetary orbits, it is also possible that they reflect misalignments between protoplanetary disks and stellar spins. This latter hypothesis predicts the presence of co-planar multi-planetary systems misaligned with their central stars. Here we re-evaluate the evidence of such an architecture that has been claimed for the KOI-89 system. KOI-89 is an early-type star with one validated transiting planet KOI-89.01/Kepler-462b (period 84.7 days, radius $3.0,R_oplus$) and one transiting planet candidate KOI-89.02 (period 207.6 days,Read More →

On the investigation of the closure relations for Gamma-Ray Bursts observed by Swift in the post-plateau phase and the GRB fundamental plane. (arXiv:2009.06740v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Srinivasaragavan_G/0/1/0/all/0/1">Gokul Prem Srinivasaragavan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dainotti_M/0/1/0/all/0/1">Maria Giovanna Dainotti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fraija_N/0/1/0/all/0/1">Nissim Fraija</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hernandez_X/0/1/0/all/0/1">Xavier Hernandez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nagataki_S/0/1/0/all/0/1">Shigehiro Nagataki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lenart_A/0/1/0/all/0/1">Aleksander Lenart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bowden_L/0/1/0/all/0/1">Luke Bowden</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wagner_R/0/1/0/all/0/1">Robert Wagner</a> Gamma-Ray Bursts (GRBs) are the most explosive phenomena in the Universe after the Big Bang. A large fraction of GRB lightcurves (LCs) shows X-ray plateaus. We perform the most comprehensive analysis of all GRBs (with known and unknown redshifts) with plateau emission observed by The Neil Gehrels Swift Observatory from its launch until AugustRead More →

Has NANOGrav found first evidence for cosmic strings?. (arXiv:2009.06607v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Blasi_S/0/1/0/all/0/1">Simone Blasi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brdar_V/0/1/0/all/0/1">Vedran Brdar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schmitz_K/0/1/0/all/0/1">Kai Schmitz</a> The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has recently reported strong evidence for a stochastic common-spectrum process affecting the pulsar timing residuals in its 12.5-year data set. We demonstrate that this process admits an interpretation in terms of a stochastic gravitational-wave background emitted by a cosmic-string network in the early Universe. We study local Nambu-Goto strings in dependence of their tension $Gmu$ and loop size $alpha$ and show that the entire viable parameter space will be probed by an array of future experiments.Read More →

The depth and the vertical extent of the energy deposition layer in a medium-class solar flare. (arXiv:2009.06064v2 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Radziszewski_K/0/1/0/all/0/1">Krzysztof Radziszewski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Falewicz_R/0/1/0/all/0/1">Robert Falewicz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rudawy_P/0/1/0/all/0/1">Pawel Rudawy</a> We analyze here variations of the position and the vertical extent of the energy deposition layer (EDL) inthe C1.6 GOES-class solar flare observed at 10:20 UT on 2012 September 10. The variations of the EDL arecontrasted with the variations of the spectra and emission intensities recorded in the H-alpha line with the very high time resolution using the MSDP spectrograph at Bialkow Observatory. The flare radiated hard X-rays (HXR) detectable up to a energy of 70 keV.Read More →

Young Faithful: The Eruptions of EC 53 as It Cycles through Filling and Draining the Inner Disk. (arXiv:2009.05268v2 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_Y/0/1/0/all/0/1">Yong-Hee Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnstone_D/0/1/0/all/0/1">Doug Johnstone</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_J/0/1/0/all/0/1">Jeong-Eun Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Herczeg_G/0/1/0/all/0/1">Gregory Herczeg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mairs_S/0/1/0/all/0/1">Steve Mairs</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Varricatt_W/0/1/0/all/0/1">Watson Varricatt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hodapp_K/0/1/0/all/0/1">Klaus W. Hodapp</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Naylor_T/0/1/0/all/0/1">Tim Naylor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pena_C/0/1/0/all/0/1">Carlos Contreras Pe&#xf1;a</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baek_G/0/1/0/all/0/1">Giseon Baek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Haas_M/0/1/0/all/0/1">Martin Haas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chini_R/0/1/0/all/0/1">Rolf Chini</a>, The <a href="http://arxiv.org/find/astro-ph/1/au:+Team_JCMT_Transient/0/1/0/all/0/1">JCMT Transient Team</a> While young stellar objects sometimes undergo bursts of accretion, these bursts usually occur sporadically, making them challenging to study observationally and to explain theoretically. We build a schematic description of cyclical bursts of the young stellar object EC 53 using near-IR andRead More →

Astrophysical hints for magnetic black holes. (arXiv:2009.03363v2 [hep-ph] UPDATED) <a href="http://arxiv.org/find/hep-ph/1/au:+Ghosh_D/0/1/0/all/0/1">Diptimoy Ghosh</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Thalapillil_A/0/1/0/all/0/1">Arun Thalapillil</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Ullah_F/0/1/0/all/0/1">Farman Ullah</a> We discuss a cornucopia of potential astrophysical signatures and constraints on magnetically charged black holes of various masses. As recently highlighted, being potentially viable astrophysical candidates with immense electromagnetic fields, they may be ideal windows to fundamental physics, electroweak symmetry restoration and non-perturbative quantum field theoretic phenomena. We investigate various potential astrophysical pointers and bounds—including limits on charges, location of stable orbits and horizons in asymptotically flat and asymptotically de Sitter backgrounds, bounds from galactic magnetic fields and dark matter measurements, characteristic electromagnetic fluxes and tell-tale gravitationalRead More →

Multi-field dark energy: cosmic acceleration on a steep potential. (arXiv:2008.13660v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Akrami_Y/0/1/0/all/0/1">Yashar Akrami</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sasaki_M/0/1/0/all/0/1">Misao Sasaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Solomon_A/0/1/0/all/0/1">Adam R. Solomon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vardanyan_V/0/1/0/all/0/1">Valeri Vardanyan</a> We argue that dark energy with multiple fields is theoretically well-motivated and predicts distinct observational signatures, in particular when cosmic acceleration takes place along a trajectory that is highly non-geodesic in field space. Such models provide novel physics compared to $Lambda$CDM and quintessence by allowing cosmic acceleration on steep potentials. From the theoretical point of view, these theories can easily satisfy the conjectured swampland constraints and may in certain cases be technically natural, potential problems which are endemic to standardRead More →

GRB Spectrum from Gradual Dissipation in a Magnetized Outflow. (arXiv:2008.10729v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Gill_R/0/1/0/all/0/1">Ramandeep Gill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Granot_J/0/1/0/all/0/1">Jonathan Granot</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beniamini_P/0/1/0/all/0/1">Paz Beniamini</a> Modeling of gamma-ray burst (GRB) prompt emission spectra sometimes requires a (quasi-) thermal spectral component in addition to the Band function. In photospheric emission models, a prominent thermal component broadened by sub-photospheric dissipation is expected to be released at the photospheric radius, $r_{rm ph}sim10^{12},$cm. We consider an ultra-relativistic strongly magnetized outflow with a striped-wind magnetic-field structure undergoing gradual and continuous magnetic energy dissipation at $r<r_s$ that heats and accelerates the flow, leading to a bulk Lorentz factor $Gamma(r)=Gamma_inftymin[1,(r/r_s)^{1/3}]$, where typically $r_{rm ph}<r_s$. Similar dynamicsRead More →