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Directional association of TeV to PeV astrophysical neutrinos with radio blazars: Recently we have shown that high-energy neutrinos above 200 TeV detected by IceCube are produced within several parsecs in the central regions of radio-bright blazars, that is active galactic nuclei with jets pointing towards us. To ind...
astro-ph_HE
Lunar gamma ray emission seen during the first year by Fermi: We report the detection of the lunar gamma-ray emission during the first year of Fermi-LAT observations. Such emission is produced by cosmic ray nuclei interacting with the lunar surface. Thanks to the solar minimum conditions and the reduced effects of heli...
astro-ph_HE
XMM-Newton Observes the Intrabinary Shock of PSR J1959+2048: In a multi-orbit (100 ks) $\mathrm{\it XMM-Newton}$ exposure of the original black widow pulsar, PSR J1959+2048, we measure the strong orbital modulation caused by intrabinary shock (IBS) emission. The IBS light curve peak appears asymmetric, which we attribu...
astro-ph_HE
Optical quasi-periodic oscillation and color behavior of blazar PKS 2155-304: PKS 2155-304 is a well studied BL Lac object in the southern sky. The historical optical data during different period have been collected and compiled. Light curves with a time span of 35 years have been constructed. The R-band light curve ...
astro-ph_HE
No X-Ray Excess from the HESS J1741-302 Region except a New Intermediate Polar Candidate: With the Suzaku satellite, we observed an unidentified TeV gamma-ray source HESS J1741$-$302 and its surroundings. No diffuse or point-like X-ray sources are detected from the bright southern emission peak of HESS J1741$-$302. F...
astro-ph_HE
MC Simulations of the Broadband Spectra of Sagittarius A* through the use of GRMHD: We present results of simulations of the spectrum of the accretion flow onto the supermassive black hole in our Galactic Centre, Sagittarius A*, generated with a coupling of Monte-Carlo (MC) radiation and general relativistic magnetoh...
astro-ph_HE
Radio Constraints on $r$-process Nucleosynthesis by Collapsars: The heaviest elements in the Universe are synthesized through rapid neutron capture ($r$-process) in extremely neutron rich outflows. Neutron star mergers were established as an important $r$-process source through the multi-messenger observation of GW1708...
astro-ph_HE
TeV gamma-ray survey of the northern sky using the ARGO-YBJ experiment: The ARGO-YBJ experiment is an extensive air shower array with full coverage RPC detectors located at Yangbajing (4300 m asl, Tibet, China). It is operated with high duty cycle (>86%) and a large field of view ($\sim$ 2sr). It continuously monitors ...
astro-ph_HE
Constraining properties of neutron star merger outflows with radio observations: The jet opening angle and inclination of GW170817 -- the first detected binary neutron star merger -- were vital to understand its energetics, relation to short gamma-ray bursts, and refinement of the standard siren-based determination o...
astro-ph_HE
An accurate and efficient numerical calculation of detonation waves in multidimensional supernova simulations using a burning limiter and adaptive quasi-statistical equilibrium: Resolving the small length-scale of thermonuclear detonation waves (TNDWs) in supernovae is currently not possible in multidimensional ful...
astro-ph_HE
Hydrodynamics of Young Supernova Remnants and the Implications for their Gamma-ray emission: Supernovae (SNe) are generally classified into Type I and Type II. Most SNe (~ 80%), including all the subtypes of Type II, and Type Ib/c, arise from the core-collapse of massive stars. During their lifetime, mass-loss from t...
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Echo-Mapping of Swift J1753.5-0127: We present two epochs of coordinated X-ray-optical timing observations of the black hole candidate Swift J1753.5-0127 during its 2005 outburst. The first epoch in July occurred at outburst peak. Two consecutive nights of observations using the McDonald Observatory Argos camera with t...
astro-ph_HE
Rates of Stellar Tidal Disruption as Probes of the Supermassive Black Hole Mass Function: Rates of stellar tidal disruption events (TDEs) by supermassive black holes (SMBHs) due to two-body relaxation are calculated using a large galaxy sample (N=146) in order to explore the sensitivity of the TDE rates to observatio...
astro-ph_HE
Mergers of binary neutron star systems: a multi-messenger revolution: On 17 August 2017, less than two years after the direct detection of gravitational radiation from the merger of two ~30 Msun black holes, a binary neutron star merger was identified as the source of a gravitational wave signal of ~100 s duration that...
astro-ph_HE
Late-time radio observations of the short GRB200522A: constraints on the magnetar model: GRB200522A is a short duration gamma-ray burst (GRB) at redshift $z$=0.554 characterized by a bright infrared counterpart. A possible, although not unambiguous, interpretation of the observed emission is the onset of a luminous k...
astro-ph_HE
Associating Fast Radio Bursts with Extragalactic Radio Sources: General Methodology and a Search for a Counterpart to FRB 170107: The discovery of a repeating fast radio burst has led to the first precise localization, an association with a dwarf galaxy, and the identification of a coincident persistent radio source....
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The TANAMI Multiwavelength Program: Dynamic SEDs of Southern Blazars: Simultaneous broadband spectral and temporal studies of blazars are an important tool for investigating active galactic nuclei (AGN) jet physics. We study the spectral evolution between quiescent and flaring periods of 22 radio-loud AGN through multi...
astro-ph_HE
From Supernova to Remnant: Tracking the Evolution of the Oldest Known X-ray Supernovae: Core-collapse supernovae (SNe) expand into a medium created by winds from the pre-SN progenitor. The SN explosion and resulting shock wave(s) heat up the surrounding plasma, giving rise to thermal X-ray emission, which depends on ...
astro-ph_HE
An Exploration of X-ray Supernova Remnants in the Milky Way and Nearby Galaxies: We probe the environmental properties of X-ray supernova remnants (SNRs) at various points along their evolutionary journey, especially the S-T phase, and their conformance with theoretically derived models of SNR evolution. The remnant ...
astro-ph_HE
Unusual Emission Variations Near the Eclipse of A Black Widow PSR J1720$-$0533: We report on an {unusually} bright observation of PSR J1720$-$0533 using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The pulsar is in a black widow system that {was discovered by the Commensal Radio Astronomy FAST Su...
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A Survey of Fermi Catalog Sources using data from the Milagro Gamma-Ray Observatory: The Fermi LAT has released a list of the most significant 205 sources with three months of Fermi data (Bright Source List). The Milagro Gamma-Ray Observatory is sensitive to gamma rays above 100 GeV with a peak sensitivity between 10...
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The first 48: Discovery and progenitor constraints on the Type Ia supernova 2013gy: We present an early-phase $g$-band light curve and visual-wavelength spectra of the normal Type Ia supernova (SN) 2013gy. The light curve is constructed by determining the appropriate S-corrections to transform KAIT natural-system $B$...
astro-ph_HE
X-ray Emission from SN 2012ca: A Type Ia-CSM Supernova Explosion in a Dense Surrounding Medium: X-ray emission is one of the signposts of circumstellar interaction in supernovae (SNe), but until now, it has been observed only in core-collapse SNe. The level of thermal X-ray emission is a direct measure of the density...
astro-ph_HE
Semi-implicit scheme for treating radiation under M1 closure in general relativistic conservative fluid dynamics codes: A numerical scheme is described for including radiation in multi-dimensional general-relativistic conservative fluid dynamics codes. In this method, a covariant form of the M1 closure scheme is used...
astro-ph_HE
Gas perturbations in cool cores of galaxy clusters: effective equation of state, velocity power spectra and turbulent heating: We present the statistical analysis of X-ray surface brightness and gas density fluctuations in cool cores of ten, nearby and bright galaxy clusters that have deep Chandra observations and sh...
astro-ph_HE
Variability of the X-ray Broad Iron Spectral Features in Active Galactic Nuclei and Black-hole Binaries: The "broad iron spectral features" are often seen in X-ray spectra of Active Galactic Nuclei (AGN) and black-hole binaries (BHB). These features may be explained either by the "relativistic disc reflection" scenar...
astro-ph_HE
Upper Limit on Correlated Current Variations in the Crab Pulsar: The high energy emission of rotation powered pulsars is supposed to be produced in "gaps" in the pulsar magnetosphere where charges are accelerated and currents are produced. The rest of the magnetosphere is supposed to be mostly a "force-free" plasma wit...
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A multi-wavelength study of the hard and soft states of MAXI J1820+070 during its 2018 outburst: We present a comprehensive multi-wavelength spectral analysis of the black hole X-ray binary MAXI J1820+070 during its 2018 outburst, utilizing AstroSat far UV, soft and hard X-ray data, along with (quasi-)simultaneous op...
astro-ph_HE
The Effect of a Cosmic Ray Precursor in SN 1006?: Like many young supernova remnants, SN 1006 exhibits what appear to be clumps of ejecta close to or protruding beyond the main blast wave. In this paper we examine 3 such protrusions along the east rim. They are semi-aligned with ejecta fingers behind the shock-front, a...
astro-ph_HE
Bose-Einstein condensate stars in combined Rastall-Rainbow gravity: We study zero and finite temperature static Bose-Einstein condensate (BEC) stars in the combined Rastall-Rainbow (RR) theory of gravity by considering different BEC equation of states (EoSs). We obtain the global properties of BEC stars by solving the ...
astro-ph_HE
Spectral and polarimetric signatures of X-ray eclipses in AGN: X-ray observations of active galactic nuclei (AGN) show variability on timescales ranging from a few hours up to a few days. Some of this variability may be associated with occultation events by clouds in the broad line region. In this work, we aim to model...
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Too small to fail: characterizing sub-solar mass black hole mergers with gravitational waves: The detection of a sub-solar mass black hole could yield dramatic new insights into the nature of dark matter and early-Universe physics, as such objects lack a traditional astrophysical formation mechanism. Gravitational wa...
astro-ph_HE
A Model of White Dwarf Pulsar AR Scorpii: A 3.56-hour white dwarf (WD) - M dwarf (MD) close binary system, AR Scorpii, was recently reported to show pulsating emission in radio, IR, optical, and UV, with a 1.97-minute period, which suggests the existence of a WD with a rotation period of 1.95 minutes. We propose a mode...
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Detailed Analysis of Filamentary Structure in the Weibel Instability: We present results of a 2D3V kinetic Vlasov simulation of the Weibel instability. The kinetic Vlasov simulation allows us to investigate the velocity distribution of dilute plasmas, in which the effect of collisions between particles is negligible, a...
astro-ph_HE
On The Evolution of The Radio Pulsar PSR J1734-3333: Recent measurements showed that the period derivative of the 'high-B' radio pulsar PSR J1734-3333 is increasing with time. For neutron stars evolving with fallback disks, this rotational behavior is expected in certain phases of the long-term evolution. Using the sam...
astro-ph_HE
Stellar oscillations in Eddington-inspired Born-Infeld gravity: We consider the stellar oscillations of relativistic stars in the Eddington-inspired Born-Infeld gravity (EiBI). In order to examine the specific frequencies, we derive the perturbation equations governing the stellar oscillations in EiBI by linearizing th...
astro-ph_HE
Detections of simultaneous brightening of gamma-ray and optical emissions of a distant blazar GB 1508+5714 at redshift 4.3: GB 1508+5714 is a high-redshift blazar ($z$ = 4.3) and a spectrally soft $\gamma$-ray source has been detected in its direction. By analyzing 11.4-yr {\it Fermi}-LAT data, significant long-term ...
astro-ph_HE
Tests of Lorentz Invariance Violation with Gamma Rays to probe Quantum Gravity: We discuss the prospects of doing tests of Lorentz invariance with gamma-rays observed with present and future ground based gamma-ray observatories.
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Probing the origin of cosmic rays in Cygnus Cocoon using ultrahigh-energy gamma-ray and neutrino observations: Recent ultrahigh energy gamma-ray observations by the HAWC up to 100 TeV and LHAASO observatories up to 1.4 PeV energies from the direction of Fermi-LAT 4FGL source 4FGL J2028.6+4110e (Cygnus Cocoon), are in...
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Understanding the cosmic ray positron flux: Recent precision measurements of the flux of cosmic ray positrons by the Alpha Magnetic Spectrometer show that the spectrum has a marked softening feature for energies close to one TeV. A possible interpretation of this result is that the observed feature measures the maximum...
astro-ph_HE
X-ray and Optical Study of Low Core Density Globular Clusters NGC6144 and E3: We report on the Chandra X-ray Observatory and Hubble Space Telescope observation of two low core density globular clusters, NGC6144 and E3. By comparing the number of X-ray sources inside the half-mass radius to those outside, we found 6 X...
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SN 2010jl: Optical to hard X-ray observations reveal an explosion embedded in a ten solar mass cocoon: (Abridged) Some supernovae (SNe) may be powered by the interaction of the SN ejecta with a large amount of circumstellar matter (CSM). Here we outline a method to measure the mass of the optically thick CSM around s...
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Hadronic vs leptonic models for $γ$-ray emission from VER J2227+608: Recent observations of VER J2227+608 reveal a broken power $\gamma$-ray spectrum with the spectral index increasing from $\sim 1.8$ in the GeV energy range to $\sim 2.3$ in the TeV range. Such a spectral break can be attributed to radiative energy los...
astro-ph_HE
Glitches detected in southern radio pulsars: Parkes pulse arrival-time data for 165 radio pulsars spanning from 1990 to 2011 have been searched for period glitches. Forty-six events out of the detected 107 glitches were found to be new contributions to the entire glitch population which currently contains approximately...
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Unwrapping the X-ray Spectra of Active Galactic Nuclei: Active galactic nuclei (AGN) are complex phenomena. At the heart of an AGN is a relativistic accretion disk around a spinning supermassive black hole (SMBH) with an X-ray emitting corona and, sometimes, a relativistic jet. On larger scales, the outer accretion dis...
astro-ph_HE
Theoretically motivated search and detection of non-thermal pulsations from PSRs J1747-2958, J2021+3651, and J1826-1256: Based on a theoretical selection of pulsars as candidates for detection at X-ray energies, we present an analysis of archival X-ray observations done with Chandra and XMM-Newton of PSR J1747-2958 (...
astro-ph_HE
Diffuse PeV neutrinos from EeV cosmic ray sources: semi-relativistic hypernova remnants in star-forming galaxies: We argue that the excess of sub-PeV/PeV neutrinos recently reported by IceCube could plausibly originate through pion-production processes in the same sources responsible for cosmic rays (CRs) with energy...
astro-ph_HE
Signatures of Hierarchical Mergers in Black Hole Spin and Mass distribution: Recent gravitational wave (GW) observations by LIGO/Virgo show evidence for hierarchical mergers, where the merging BHs are the remnants of previous BH merger events. These events may carry important clues about the astrophysical host enviro...
astro-ph_HE
Accelerated binary black holes in globular clusters: forecasts and detectability in the era of space-based gravitational-wave detectors: The motion of the center of mass of a coalescing binary black hole (BBH) in a gravitational potential imprints a line-of-sight acceleration (LOSA) onto the emitted gravitational wav...
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Interpreting the large amplitude X-ray variation of GRS 1915+105 and IGR J17091-3624 as modulations of an accretion disc: Using the flux resolved spectroscopy for the first time, we analyse the RXTE/PCA data of the black hole X-ray binaries GRS 1915+105 and IGR J17091-3624, when both sources show large amplitude, qua...
astro-ph_HE
Neutron star dynamics under time dependent external torques: The two component model describes neutron star dynamics incorporating the response of the superfluid interior. Conventional solutions and applications involve constant external torques, as appropriate for radio pulsars on dynamical timescales. We present the ...
astro-ph_HE
Supermassive Black Hole Winds in X-rays -- SUBWAYS. I. Ultra-fast outflows in QSOs beyond the local Universe: We present a new X-ray spectroscopic study of $22$ luminous ($2\times10^{45}\lesssim L_{\rm bol}\rm /erg\,s^{-1} \lesssim 2\times10^{46}$) active galactic nuclei (AGNs) at intermediate-redshift ($0.1 \lesssim...
astro-ph_HE
Effects of a non-universal IMF and binary parameter correlations on compact binary mergers: Binary population synthesis provides a direct way of studying the effects of different choices of binary evolution models and initial parameter distributions on present-day binary compact merger populations, which can then be ...
astro-ph_HE
The link between broad emission line fluctuations and non-thermal emission from the inner AGN jet: AGN reverberate when the broad emission lines respond to changes of the ionizing thermal continuum emission. Reverberation measurements have been commonly used to estimate the size of the broad-line region (BLR) and the...
astro-ph_HE
Dark matter annihilation and jet quenching phenomena in the early universe: Dark-matter particles like neutralinos should decouple from the hot cosmic plasma at temperatures of about 40 GeV. Later they can annihilate each other into standard-model particles, which are injected into the dense primordial plasma and qui...
astro-ph_HE
Radiation Pressure and Mass Ejection in Rho-like States of GRS 1915+105: We present a unifying scenario to address the physical origin of the diversity of X-ray lightcurves within the rho variability class of the microquasar GRS 1915+105. This 'heartbeat' state is characterized by a bright flare that recurs every ~50-1...
astro-ph_HE
Radioactive heating rate of r-process elements and macronova light curve: We study the heating rate of r-process nuclei and thermalization of decay products in neutron star merger ejecta and macronova (kilonova) light curves. Thermalization of charged decay products, i.e., electrons, $\alpha$-particles, and fission fra...
astro-ph_HE
Search for Individual Ultrahigh Energy Cosmic Ray Sources in the Future Data: We propose a new way to detect individual bright Ultra-High Energy Cosmic Ray (UHECR) sources above background if the Galactic Magnetic Field (GMF) gives the main contribution to UHECR deflections. This method can be directly applied to map...
astro-ph_HE
On the equivalent width of the Fe K$α$ line produced by a dusty absorber in active galactic nuclei: Obscured AGNs provide an opportunity to study the material surrounding the central engine. Geometric and physical constraints on the absorber can be deduced from the reprocessed AGN emission. In particular, the obscuri...
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ALMA CO Observations of the Gamma-Ray Supernova Remnant RX J1713.7-3946: Discovery of Shocked Molecular Cloudlets and Filaments at 0.01 pc scales: RX J1713.7-3946 is a unique core-collapse SNR that emits bright TeV gamma-rays and synchrotron X-rays caused by cosmic rays, in addition to interactions with interstellar ...
astro-ph_HE
Correlated variability of the reflection fraction with the X-ray flux and spectral index for Mkn 478: The X-ray spectrum of Mkn 478 is known to be dominated by a strong soft excess which can be described using relativistic blurred reflection. Using observations from {\it XMM-Newton}, {\it AstroSat} and {\it Swift}, w...
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Fermi LAT Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes: The diffuse Galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compto...
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Effects of shock and turbulence properties on electron acceleration: Using test particle simulations we study electron acceleration at collisionless shocks with a two-component model turbulent magnetic field with slab component including dissipation range. We investigate the importance of shock normal angle $\theta_{Bn...
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TESS Shines Light on the Origin of the Ambiguous Nuclear Transient ASASSN-18el: We analyze high-cadence data from the Transiting Exoplanet Survey Satellite (TESS) of the ambiguous nuclear transient (ANT) ASASSN-18el. The optical changing-look phenomenon in ASASSN-18el has been argued to be due to either a drastic cha...
astro-ph_HE
Log-normal flux distribution of bright Fermi blazars: We present the results of the $\gamma$-ray flux distribution study on the brightest blazars which are observed by the \emph{Fermi}-LAT. We selected 50 brightest blazars based on the maximum number of detection reported in the LAT third AGN catalog. We performed stan...
astro-ph_HE
The Role of Superluminal Electromagnetic Waves in Pulsar Wind Termination Shocks: The dynamics of a standing shock front in a Poynting-flux dominated relativistic flow is investigated by using a one-dimensional, relativistic, two-fluid simulation. An upstream flow containing a circularly polarized, sinusoidal magneti...
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The NANOGrav 11-year Data Set: High-precision timing of 45 Millisecond Pulsars: We present high-precision timing data over time spans of up to 11 years for 45 millisecond pulsars observed as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project, aimed at detecting and characteriz...
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Exploding neutron stars in close binaries: The discovery of GW signal from merging neutron stars by LIGO on 17th August 2017 was followed by a short GRB170817A discovered by FERMI and INTEGRAL 1.7 seconds after the loss of the GW signal when it just reached its maximum. Here we present a reproduction of the first paper...
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Characterising the rotational irregularities of the Vela pulsar from 21 yr of phase-coherent timing: Pulsars show two classes of rotational irregularities that can be used to understand neutron-star interiors and magnetospheres: glitches and timing noise. Here we present an analysis of the Vela pulsar spanning nearly...
astro-ph_HE
Stability of interlinked neutron vortex and proton flux-tube arrays in a neutron star -- III. Proton feedback: The coupled, time-dependent Gross-Pitaevskii and Ginzburg-Landau equations are solved simultaneously in three dimensions to investigate the equilibrium state and far-from-equilibrium, spin-down dynamics of a...
astro-ph_HE
The drifting subpulses of PSR B0031-07 and its synchronously modulated radio polarization: We establish that for PSR B0031-07 the orthogonal polarization modes switch at a single pulse level synchronously with the periodic drifting subpulses seen in total intensity. There are only four other pulsars known for which t...
astro-ph_HE
Indirect evidence of GeV Dark Matter: Recently, an excess of GeV gamma ray near the Galactic Centre has beenvreported. The spectrum obtained can be best fitted with the annihilationvof $30-40$ GeV dark matter particles through $b \bar{b}$ channel. In this letter, I show that this annihilation model can also solve the m...
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Relativistic Viscous Radiation Hydrodynamic Simulations of Geometrically Thin Disks: I. Thermal and Other Instabilities: We present results from two-dimensional, general relativistic, viscous, radiation hydrodynamic numerical simulations of Shakura-Sunyaev thin disks accreting onto stellar mass Schwarzschild black ho...
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Properties of strongly magnetized ultradense matter and their imprints on magnetar pulsations: We investigate the effect of strong magnetic fields on the adiabatic radial oscillations of hadronic stars. We describe magnetized hadronic matter within the framework of the relativistic nonlinear Walecka model and integra...
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A simplified view of blazars: why BL Lacertae is actually a quasar in disguise: We put forward a scenario where blazars are classified as flat-spectrum radio quasars, BL Lacs, low synchrotron, or high synchrotron peaked objects according to a varying combination of Doppler boosted radiation from the jet, emission fro...
astro-ph_HE
From Supernova to Remnant: Tracking the Evolution of the Oldest Known X-ray Supernovae: Core-collapse supernovae (SNe) expand into a medium created by winds from the pre-SN progenitor. The SN explosion and resulting shock wave(s) heat up the surrounding plasma, giving rise to thermal X-ray emission, which depends on ...
astro-ph_HE
3 to 12 millimetre studies of dense gas towards the western rim of supernova remnant RX J1713.7-3946: The young X-ray and gamma-ray-bright supernova remnant RXJ1713.7-3946 (SNR G347.3-0.5) is believed to be associated with molecular cores that lie within regions of the most intense TeV emission. Using the Mopra teles...
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On the Origin of Diffuse Radio Emission in Abell 85 -- Insights from new GMRT Observations: Extended, steep, and ultra-steep spectrum radio emission in a galaxy cluster is usually associated with recent mergers. Simulations show that radio phoenixes are aged radio galaxy lobes whose emission reactivates when a low Ma...
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Supernova Explosions inside Carbon-Oxygen Circumstellar Shells: Motivated by a recent discovery of Supernova 2010gx and numerical results of Fryer et al.(2010), we simulate light curves for several type I supernova models, enshrouded by dense circumstellar shells, or "super-wind", rich in carbon and oxygen and having n...
astro-ph_HE
The time-dependent one-zone hadronic model - First principles: We present a time-dependent approach to the one-zone hadronic model in the case where the photon spectrum is produced by ultrarelativistic protons interacting with soft photons that are produced from protons and low magnetic fields. Assuming that protons ar...
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A generic method to constrain the dark matter model parameters from Fermi observations of dwarf spheroids: Observation of gamma-rays from dwarf galaxies is an effective way to search for particle dark matter. Using 4-year data of Fermi-LAT observations on a series of Milky Way satellites, we develop a general way to ...
astro-ph_HE
The spin and orbit of the newly discovered pulsar IGR J17480-2446: We present an analysis of the spin and orbital properties of the newly discovered accreting pulsar IGR J17480-2446, located in the globular cluster Terzan 5. Considering the pulses detected by the Rossi X-ray Timing Explorer at a period of 90.539645(2) ...
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TeV gamma-ray survey of the Northern sky using the ARGO-YBJ detector: The ARGO-YBJ detector is an extensive air shower array that has been used to monitor the northern $\gamma$-ray sky at energies above 0.3 TeV from 2007 November to 2013 January. In this paper, we present the results of a sky survey in the declination ...
astro-ph_HE
Suzaku Discovery of a Slowly Varying Hard X-ray Continuum from the Type I Seyfert Galaxy NGC 3516: The bright type I Seyfert galaxy NGC 3516 was observed by {\it Suzaku} twice, in 2005 October 12--15 and 2009 October 28--November 2, for a gross time coverage of 242 and 544 ksec and a net exposure of 134 and 255 ksec,...
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Full Monte-Carlo description of the Moscow State University Extensive Air Shower experiment: The Moscow State University Extensive Air Shower (EAS-MSU) array studied high-energy cosmic rays with primary energies ~(1-500) PeV in the Northern hemisphere. The EAS-MSU data are being revisited following recently found ind...
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Cosmic-ray acceleration and escape from post-adiabatic Supernova remnants: Supernova remnants are known to accelerate cosmic rays on account of their non-thermal emission of radio waves, X-rays, and gamma rays. Although there are many models for the acceleration of cosmic rays in Supernova remnants, the escape of cos...
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Cosmic ray driven Galactic winds: The escape of cosmic rays from the Galaxy leads to a gradient in the cosmic ray pressure that acts as a force on the background plasma, in the direction opposite to the gravitational pull. If this force is large enough to win against gravity, a wind can be launched that removes gas fro...
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Environmental dependence of Type IIn supernova properties: Type IIn supernovae occur when stellar explosions are surrounded by dense hydrogen-rich circumstellar matter. The dense circumstellar matter is likely formed by extreme mass loss from their progenitors shortly before they explode. The nature of Type IIn superno...
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X-Ray Emission from the Galactic Supernova Remnant G12.0-0.1: We present results of the Suzaku/XIS observation around the radio supernova remnant (SNR) G12.0-0.1. No significant diffuse emission extending in or along the radio shell was observed. Instead two compact X-ray sources, Suzaku J181205-1835 and Suzaku J181210...
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GRBs on probation: testing the UHE CR paradigm with IceCube: Gamma ray burst (GRB) fireballs provide one of very few astrophysical environments where one can contemplate the acceleration of cosmic rays to energies that exceed 10^20 eV. The assumption that GRBs are the sources of the observed cosmic rays generates a cal...
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An up-scattered cocoon emission model of Gamma-Ray Burst high-energy lags: The Fermi Gamma-ray Space Telescope recently detected the most energetic gamma-ray burst so far, GRB 080916C, and reported its detailed temporal properties in an extremely broad spectral range: (i) the time-resolved spectra are well described ...
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Extragalactic cosmic ray sources with very small contribution in the particle flux on the Earth and their study: Possible existence of extragalactic ultra-high energy cosmic ray sources giving a very small particle flux on the Earth is considered. Accretion discs around supermassive black holes where particles are ac...
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Strong late-time circumstellar interaction in the peculiar supernova iPTF14hls: We present a moderate-resolution spectrum of the peculiar Type II supernova iPTF14hls taken on day 1153 after discovery. This spectrum reveals the clear signature of shock interaction with dense circumstellar material (CSM). We suggest th...
astro-ph_HE
The origin of the first neutron star -- neutron star merger: The first neutron star-neutron star (NS-NS) merger was discovered on August 17, 2017 through gravitational waves (GW170817) and followed with electromagnetic observations. This merger was detected in an old elliptical galaxy with no recent star formation. We ...
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Characteristics of the diffuse astrophysical electron and tau neutrino flux with six years of IceCube high energy cascade data: We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010 -- 2015. Assuming standard oscillations, the astrophysical n...
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Modeling Magnetic Disk-Wind State Transitions in Black Hole X-ray Binaries: We analyze three prototypical black hole (BH) X-ray binaries (XRBs), \4u1630, \gro1655\ and \h1743, in an effort to systematically understand the intrinsic state transition of the observed accretion-disk winds between \windon\ and \windoff\ s...
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Calculating transient rates from surveys: We have developed a method to determine the transient surface density and transient rate for any given survey, using Monte-Carlo simulations. This method allows us to determine the transient rate as a function of both the flux and the duration of the transients in the whole flu...
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A search for lines in the bright X-ray afterglow of GRB120711A: GRB120711A, discovered and rapidly localized by the INTEGRAL satellite, attracted particular interest due to its high gamma-ray fluence, very bright X-ray afterglow, and the detection of a prompt optical transient and of long-lasting emission at GeV energi...
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Long duration radio transients lacking optical counterparts are possibly Galactic Neutron Stars: (abridged) Recently, a new class of radio transients in the 5-GHz band was detected by Bower et al. We present new deep near-Infrared (IR) observations of the field containing these transients, and find no counterparts do...
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A pulsar in a binary with a compact object in the mass gap between neutron stars and black holes: Among the compact objects observed in gravitational wave merger events a few have masses in the gap between the most massive neutron stars (NSs) and least massive black holes (BHs) known. Their nature and the formation o...
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