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A Search for Fast Optical Transients in the Pan-STARRS1 Medium-Deep Survey: M Dwarf Flares, Asteroids, Limits on Extragalactic Rates, and Implications for LSST: [Abridged] We present a search for fast optical transients (~0.5 hr-1 day) using repeated observations of the Pan-STARRS1 Medium-Deep Survey (PS1/MDS) fiel...
astro-ph_HE
The Swift/BAT Hard X-ray Transient Monitor: The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolut...
astro-ph_HE
The High Time Resolution Universe Pulsar Survey - VII: discovery of five millisecond pulsars and the different luminosity properties of binary and isolated recycled pulsars: This paper presents the discovery and timing parameters for five millisecond pulsars (MSPs), four in binary systems with probable white dwarf ...
astro-ph_HE
Constraints on Proton Synchrotron Origin of Very High Energy Gamma Rays from the Extended Jet of AP Librae: The multi-wavelength photon spectrum from the BL Lac object AP Librae extends from radio to TeV gamma rays. The X-ray to very high energy gamma ray emission from the extended jet of this source has been modeled...
astro-ph_HE
A falling Corona model for the anomalous behavior of the broad emission lines in NGC 5548: NGC 5548 has been intensively monitored by the AGN Space Telescope and Optical Reverberation Mapping collaboration. Approximately after half of the light curves, the correlation between the broad emission lines and the lag-corr...
astro-ph_HE
Swift X-ray and ultraviolet observations of the shortest orbital period double-degenerate system RX J0806.3+1527 (HM Cnc): The system RX J0806.3+1527 (HM Cnc) is a pulsating X-ray source with 100 per cent modulation on a period of 321.5 s (5.4 min). This period reflects the orbital motion of a close binary consisting...
astro-ph_HE
X-ray Spectroscopy of the gamma-ray Brightest Nova V906 Car (ASASSN-18fv): Shocks in gamma-ray emitting classical novae are expected to produce bright thermal and non-thermal X-rays. We test this prediction with simultaneous NuSTAR and Fermi/LAT observations of nova V906 Car, which exhibited the brightest GeV gamma-r...
astro-ph_HE
Accretion disc by Roche lobe overflow in the supergiant fast X-ray transient IGR J08408-4503: Supergiant fast X-ray transients (SFXTs) are X-ray binary systems with a supergiant companion and likely a neutron star, which show a fast ($\sim 10^3$ s) and high variability with a dynamic range up to $10^{5-6}$. Given the...
astro-ph_HE
What Powered the Kilonova-Like Emission After GRB 230307A in the Framework of a Neutron Star-White Dwarf Merger?: The second brightest gamma-ray burst, GRB 230307A (with a duration $T_{90}$ ~ 40 s), exhibited characteristics indicative of a magnetar engine during the prompt emission phase. Notably, a suspected kilono...
astro-ph_HE
The Knee and the Second Knee of the Cosmic-Ray Energy Spectrum: The cosmic ray flux measured by the Telescope Array Low Energy Extension (TALE) exhibits three spectral features: the knee, the dip in the $10^{16}$ eV decade, and the second knee. Here the spectrum has been measured for the first time using fluorescence t...
astro-ph_HE
Revisit of Local X-ray Luminosity Function of Active Galactic Nuclei with the MAXI Extragalactic Survey: We construct a new X-ray (2--10 keV) luminosity function of Compton-thin active galactic nuclei (AGNs) in the local universe, using the first MAXI/GSC source catalog surveyed in the 4--10 keV band. The sample cons...
astro-ph_HE
The influence of outflows on the 1/f-like luminosity fluctuations: In accretion systems, outflows may have significant influence on the luminosity fluctuations. In this paper, following the Lyubarskii's general scheme, we revisit the power spectral density of luminosity fluctuations by taking into account the role of o...
astro-ph_HE
Evolution of the X-ray Properties of the Transient Magnetar XTE J1810-197: We report on X-ray observations of the 5.54 s transient magnetar XTE J1810-197 using the XMM-Newton and Chandra observatories, analyzing new data from 2008 through 2014, and re-analyzing data from 2003 through 2007 with the benefit of these si...
astro-ph_HE
Resonant scattering in the Perseus Cluster: spectral model for constraining gas motions with Astro-H: X-ray spectra from cores of galaxy clusters can be strongly distorted by resonant scattering of line photons, affecting metal abundance and gas velocity measurements. We introduce simulated spectral models that take ...
astro-ph_HE
Constraints on MeV dark matter and primordial black holes: Inverse Compton signals at the SKA: We investigate the possibilities for probing MeV dark matter (DM) particles and primordial black holes (PBHs) (for masses $\sim 10^{15}$--$10^{17}$ g) at the upcoming radio telescope SKA, using photon signals from the Inver...
astro-ph_HE
Three-flavor collective neutrino conversions with multi-azimuthal-angle instability in an electron-capture supernova model: We investigate the multi-azimuthal angle (MAA) effect on collective neutrino oscillation by considering the three-dimensional neutrino momentum distribution in a realistic electron-capture super...
astro-ph_HE
Possible role of magnetic reconnection in the electromagnetic counterpart of binary black hole merger: We propose a qualitative scenario to interpret the argued association between the direct measurement of the gravitational wave event GW150914 by Laser Interferometer Gravitational Wave Observatory (LIGO)-Virgo colla...
astro-ph_HE
The Ultra-Fast Outflow of the Quasar PG 1211+143 as Viewed by Time-Averaged Chandra Grating Spectroscopy: We present a detailed X-ray spectral study of the quasar PG 1211+143 based on Chandra High Energy Transmission Grating Spectrometer (HETGS) observations collected in a multi-wavelength campaign with UV data using...
astro-ph_HE
AKARI Near-infrared Spectral Observations of Shocked H2 Gas of the Supernova Remnant IC 443: We present near-infrared (2.5 - 5.0 um) spectra of shocked H2 gas in the supernova remnant IC 443, obtained with the satellite AKARI. Three shocked clumps-known as B, C, and G-and one background region were observed, and only...
astro-ph_HE
Magnetic-Field Amplification in the Thin X-ray Rims of SN1006: Several young supernova remnants (SNRs), including SN1006, emit synchrotron X-rays in narrow filaments, hereafter thin rims, along their periphery. The widths of these rims imply 50 to 100 $\mu$G fields in the region immediately behind the shock, far larger...
astro-ph_HE
Supernova Shock Breakout Through a Wind: The breakout of a supernova shock wave through the progenitor star's outer envelope is expected to appear as an X-ray flash. However, if the supernova explodes inside an optically-thick wind, the breakout flash is delayed. We present a simple model for estimating the conditions ...
astro-ph_HE
Observations of High-Energy Gamma-Ray Emission Toward the Galactic Centre with the Fermi Large Area Telescope: The inner region of the Milky Way is one of the most interesting and complex regions of the gamma-ray sky. The intense interstellar emission and resolved point sources, as well as potential contributions by ...
astro-ph_HE
Constraining black hole spins with low-frequency quasi-periodic oscillations in soft states: Black hole X-ray transients show a variety of state transitions during their outburst phases, characterized by changes in their spectral and timing properties. In particular, power density spectra (PDS) show quasi periodic os...
astro-ph_HE
Why not any tau double bang in Icecube, yet?: High Energy Neutrino Astronomy has been revealed by a sudden change in the flavor composition around maximal energies since three years of recording in ice km detector. However these discover didn' t led to any clear promised Neutrino Astronomy land yet. No correlation with...
astro-ph_HE
Vertical Structure of Neutrino Dominated Accretion Disks and Neutrino Transport in the disks: We investigate the vertical structure of neutrino dominated accretion disks by self-consistently considering the detailed microphysics, such as the neutrino transport, vertical hydrostatic equilibrium, the conservation of le...
astro-ph_HE
Optical Afterglows and IGM Attenuation: Because of their cosmological origin, gamma-ray burst (GRB) optical afterglows are attenuated when they pass intergalactic absorbers in the GRB line-of-sight. Without the knowledge of the number of absorbers and their physical properties, the effect of absorption on the observed ...
astro-ph_HE
First combined studies on Lorentz Invariance Violation from observations of astrophysical sources: Imaging Atmospheric Cherenkov Telescopes study the highest energy (up to tens of TeV) photon emission coming from nearby and distant astrophysical sources, thus providing valuable results from searches for Lorentz Invar...
astro-ph_HE
Interpreting the relation between the gamma-ray and infrared luminosities of star-forming galaxies: It has been found that there is a quasi-linear scaling relationship between the gamma-ray luminosity in GeV energies and the total infrared luminosity of star-forming galaxies, i.e. $L_{\gamma}\propto L_{\rm IR}^{\alph...
astro-ph_HE
A search for fast radio burst-like emission from Fermi gamma-ray bursts: We report the results of the rapid follow-up observations of gamma-ray bursts (GRBs) detected by the Fermi satellite to search for associated fast radio bursts. The observations were conducted with the Australian Square Kilometre Array Pathfinder ...
astro-ph_HE
Observational signatures of stellar explosions driven by relativistic jets: The role of relativistic jets in unbinding the stellar envelope during a supernova (SN) associated with a gamma-ray burst (GRB) is unclear. To study that, we explore observational signatures of stellar explosions that are driven by jets. We f...
astro-ph_HE
The luminosity function and the rate of Swift's Gamma Ray Bursts: We invert directly the redshift - luminosity distribution of observed long Swift GRBs to obtain their rate and luminosity function. Our best fit rate is described by a broken power law that rises like (1+z)^2.1{+0.5-0.6} for 0<z<3 and decrease like (1+z)...
astro-ph_HE
The optical noise monitoring systems of Lake Baikal environment for the Baikal-GVD telescope: We present data on the luminescence of the Baikal water medium collected with the Baikal-GVD neutrino telescope. This three-dimensional array of light sensors allows the observation of time and spatial variations of the ambi...
astro-ph_HE
Deexcitation nuclear gamma-ray line emission from low-energy cosmic rays in the inner Galaxy: Recent observations of high ionization rates of molecular hydrogen in diffuse interstellar clouds point to a distinct low-energy cosmic-ray component. Supposing that this component is made of nuclei, two models for the origi...
astro-ph_HE
Revealing Double White Dwarf Mergers with Multi-messenger Signals: A significant number of double white dwarfs (DWDs) are believed to merge within the Hubble time due to the gravitational wave (GW) emission during their inspiraling phase. The outcome of a DWD system is either a type Ia Supernova as the double-degenerat...
astro-ph_HE
Swift Observations of Hard X-ray Emitting White Dwarfs in Symbiotic Stars: The X-ray emission from most accreting white dwarfs (WDs) in symbiotic binary stars is quite soft. Several symbiotic WDs, however, produce strong X-ray emission at energies greater than ~20 keV. The Swift BAT instrument has detected hard X-ray...
astro-ph_HE
Supernova 2013by: A Type IIL Supernova with a IIP-like light curve drop: We present multi-band ultraviolet and optical light curves, as well as visual-wavelength and near-infrared spectroscopy of the Type II linear (IIL) supernova (SN) 2013by. We show that SN 2013by and other SNe IIL in the literature, after their line...
astro-ph_HE
Signatures of the disk-jet coupling in the Broad-line Radio Quasar 4C+74.26: Here we explore the disk-jet connection in the broad-line radio quasar 4C+74.26, utilizing the results of the multiwavelength monitoring of the source. The target is unique in that its radiative output at radio wavelengths is dominated by a ...
astro-ph_HE
Status of the Lunar Detection Mode for Cosmic Particles of LOFAR: Cosmic particles hitting Earth's moon produce radio emission via the Askaryan effect. If the resulting radio ns-pulse can be detected by radio telescopes, this technique potentially increases the available collective area for ZeV scale particles by sever...
astro-ph_HE
On the Polarized Absorption Lines in Gamma-ray Burst Optical Afterglows: Spectropolarimetric measurements of gamma-ray burst (GRB) optical afterglows contain polarization information for both continuum and absorption lines. Based on the Zeeman effect, an absorption line in a strong magnetic field is polarized and split...
astro-ph_HE
Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory: The Crab Nebula is the brightest TeV gamma-ray source in the sky and has been used for the past 25 years as a reference source in TeV astronomy, for calibration and verification of new TeV instruments. The High Altitude Water Cherenkov Observatory (HAW...
astro-ph_HE
The Intrinsic Properties of Multiwavelength Energy Spectra for Fermi Teraelectronvolt Blazars: In this paper, we have selected a sample of 64 teraelectronvolt blazars, with redshift, from those classified in the fourth Fermi Large Area Telescope source catalog\footnote{\url{https://fermi.gsfc.nasa.gov/ssc/data/access...
astro-ph_HE
Bayesian Analysis of Hybrid EoS based on Astrophysical Observational Data: We perform a Bayesian analysis of probability measures for compact star equations of state using new, disjunct constraints for mass and radius. The analysis uses a simple parametrization for hybrid equations of state to investigate the possibi...
astro-ph_HE
A multi-wavelength study of the gamma-ray binary candidate HESS J1832-093: We investigate the nature of the unidentified very-high-energy (VHE) gamma-ray object, HESS J1832-093, in a multi-wavelength context. Based on X-ray variability and spectral index ($\Gamma_X\sim\,1.5$), and its broad-band spectrum (which was r...
astro-ph_HE
X-ray nova MAXI J1828-249. Evolution of the broadband spectrum during its 2013-2014 outburst: Based on data from the SWIFT, INTEGRAL, MAXI/ISS orbital observatories, and the ground-based RTT-150 telescope, we have investigated the broadband (from the optical to the hard X-ray bands) spectrum of the X-ray nova MAXI J1...
astro-ph_HE
X-rays from the episodic dust maker WR 137: We present an analysis of the XMM-Newton observation of the episodic dust maker WR 137. Global spectral fits show that its X-ray spectrum is well matched by a two-temperature optically-thin plasma emission (kT_1 ~ 0.4 keV and kT_2 ~ 2.2 keV). If we adopt the colliding stellar...
astro-ph_HE
The evaporating primordial black hole fraction in cool-core galaxy clusters: Recent studies of gamma-ray, cosmic-ray and radio data put stringent constraints on the fraction of primordial black holes (PBHs) in our universe. In this article, we propose a new indirect method in using the X-ray luminosity data of cool-c...
astro-ph_HE
The GMRT High Resolution Southern Sky Survey for pulsars and transients -- VI: Discovery of nulling, localisation and timing of PSR J1244-4708: Many pulsars in the known population exhibit nulling, which is characterised by a sudden cessation and subsequent restoration of radio emission. In this work, we present the ...
astro-ph_HE
Constraints on UHECR sources and extragalactic magnetic fields from directional anisotropies: A dipole anisotropy in ultra-high-energy cosmic ray (UHECR) arrival directions, of extragalactic origin, is now firmly established at energies E > 8 EeV. Furthermore, the UHECR angular power spectrum shows no power at smalle...
astro-ph_HE
Data-driven extrapolation schemes of Fermi-LAT spectra to the VHE: After 10 years of operations of the Large Area Telescope (LAT), a high-energy pair-creation telescope onboard the Fermi satellite, the Fermi Collaboration has produced two major catalogs: the 4FGL and the 3FHL. These catalogs represent the best sample o...
astro-ph_HE
Evidence of a Hadronic Origin for the TeV Source J1834-087: We report on the discovery of compact, narrow OH line emission from the hydroxl molecule at 1720 MHz toward the extended TeV source J1834-087. The origin of this high energy emission is unknown; it could be powered by one or more candidate neutron stars (lepto...
astro-ph_HE
An XMM-Newton view of the dipping low-mass X-ray binary XTE J1710-281: (abridged) We analyzed the archived XMM-Newton observation of the poorly studied low-mass X-ray binary XTE J1710-281 performed in 2004 that covered one orbital period of the system (3.8 hr). The source shows dips as well as eclipses, hence it is vie...
astro-ph_HE
The Morphology and Dynamics of Relativistic Jets with Relativistic Equation of State: We study the effect of plasma composition on the dynamics and morphology of the relativistic astrophysical jets. Our work is based on a relativistic total variation diminishing (TVD) simulation code. We use a relativistic equation o...
astro-ph_HE
Sensitivity of the correlation between the depth of shower maximum and the muon shower size to the cosmic ray composition: The composition of ultra-high energy cosmic rays is an important issue in astroparticle physics research, and additional experimental results are required for further progress. Here we investigat...
astro-ph_HE
Kinematics of Parsec-Scale Jets of Gamma-Ray Bright Blazars at 43 GHz during Ten Years of the VLBA-BU-BLAZAR Program: We analyze the parsec-scale jet kinematics from 2007 June to 2018 December of a sample of $\gamma$-ray bright blazars monitored roughly monthly with the Very Long Baseline Array at 43 GHz under the VL...
astro-ph_HE
Late Afterglow Bump/Plateau around the Jet Break: Signature of a free-to-shocked wind Environment in Gamma-ray Burst: A number of gamma-ray bursts (GRBs) exhibit the late simultaneous bumps in their optical and Xray afterglows around the jet break. Its origin is unclear. Based on the following two facts, we suggest t...
astro-ph_HE
An Occultation Event in Centaurus A and the Clumpy Torus Model: We have analyzed 16 months of sustained monitoring observations of Cen A from the Rossi X-ray Timing Explorer to search for changes in the absorbing column in the line of sight to the central nucleus. We present time-resolved spectroscopy which indicates t...
astro-ph_HE
Cosmic Evolution of Stellar-mass Black Hole Merger Rate in Active Galactic Nuclei: Binary black hole mergers encode information about their environment and the astrophysical processes that led to their formation. Measuring the redshift dependence of their merger rate will help probe the formation and evolution of gal...
astro-ph_HE
Reapproaching the Spin Estimate of GX 339-4: We systematically reanalyze two previous observations of the black hole (BH) GX 339-4 in the very high and intermediate state taken with $\emph{XMM-Newton}$ and $\emph{Suzaku}$. We utilize up-to-date data reduction procedures and implement the recently developed, self-consis...
astro-ph_HE
Unraveling the Geometry of the Crab Nebula's "Inner Ring": Chandra images of the Crab Nebula resolve the detailed structure of its "inner ring", possibly a termination shock where pulsar-accelerated relativistic particles begin to emit X radiation. Analysis of these images finds that the center of the ellipse-presumabl...
astro-ph_HE
Low metallicity natal environments and black hole masses in Ultraluminous X-ray Sources: We review the available estimates of the masses of the compact object in Ultraluminous X-ray Sources (ULXs) and critically reconsider the stellar-mass versus intermediate-mass black hole interpretations. Black holes of several hu...
astro-ph_HE
Overview of MHz air shower radio experiments and results: In this paper, I present a review of the main results obtained in the last 10 years in the field of radio-detection of cosmic-ray air showers in the MHz range. All results from all experiments cannot be reported here so that I will focus on the results more than...
astro-ph_HE
Neutron Stars with realistic EoS in f(R) theories of gravity: In this paper, we examine neutron star structure in perturbative $f(R)$ gravity models with realistic equation of state. We obtain mass-radius relations in two gravity models of the form $f_{1}(R)=R+ \alpha R(e^{-R/R_0}-1)$ and $f_{2}(R)=R+\alpha R^2$. For t...
astro-ph_HE
Light Curve Modeling of Superluminous Supernova 2006gy: Collision between Supernova Ejecta and Dense Circumstellar Medium: We show model light curves of superluminous supernova 2006gy on the assumption that the supernova is powered by the collision of supernova ejecta and its dense circumstellar medium. The initial c...
astro-ph_HE
diffSph: a Python tool to compute diffuse signals from dwarf spheroidal galaxies: So far no diffuse emissions in dwarf spheroidal satellites of the Milky Way have ever been observed. Given that dwarf galaxies are predominantly composed of Dark Matter, the discovery of these signals could offer valuable insights into ...
astro-ph_HE
A Comparative Study of Long and Short GRBs. I. Overlapping Properties: Gamma ray bursts (GRBs) are classified into long and short categories based on their durations. Broad band studies suggest that these two categories of objects roughly correspond to two different classes of progenitor systems, i.e. compact star merg...
astro-ph_HE
A Bayesian test for periodic signals in red noise: Many astrophysical sources, especially compact accreting sources, show strong, random brightness fluctuations with broad power spectra in addition to periodic or quasi-periodic oscillations (QPOs) that have narrower spectra. The random nature of the dominant source of ...
astro-ph_HE
The puzzling symbiotic X-ray system 4U1700+24: Symbiotic X-ray binaries form a subclass of low-mass X-ray binary systems consisting of a neutron star accreting material from a red giant donor star via stellar wind or Roche lobe overflow. Only a few confirmed members are currently known; 4U 1700+24 is a good candidate a...
astro-ph_HE
The Swift Serendipitous Survey in deep XRT GRB fields (SwiftFT) I. The X-ray catalog and number counts: We searched for X-ray serendipitous sources in over 370 Swift-XRT fields centered on gamma ray bursts detected between 2004 and 2008 and observed with total exposures ranging from 10 ks to over 1 Ms. This defines t...
astro-ph_HE
Solar Wind Charge Exchange contribution to the ROSAT All Sky Survey Maps: DXL (Diffuse X-ray emission from the Local Galaxy) is a sounding rocket mission designed to estimate the contribution of Solar Wind Charge eXchange (SWCX) to the Diffuse X-ray Background (DXB) and to help determine the properties of the Local Hot...
astro-ph_HE
Modeling the oxygen K absorption in the interstellar medium: an {\it XMM}-Newton view of Sco X-1: We investigate the absorption structure of the oxygen in the interstellar medium by analyzing {\it XMM}-Newton observations of the low mass X-ray binary Sco X-1. We use simple models based on the O {\sc i} atomic cross s...
astro-ph_HE
VERITAS Observations of the Unidentified Point Source HESS J1943+213: The H.E.S.S. Galactic plane scan has revealed a large population of Galactic very high energy (VHE; E > 100 GeV) emitters. The majority of the galactic sources are extended and can typically be associated with pulsar wind nebulae (35%) and supernova ...
astro-ph_HE
Gravitational waves from the Papaloizou-Pringle instability in black hole-torus systems: Black hole (BH)--torus systems are promising candidates for the central engine of gamma-ray bursts (GRBs), and also possible outcomes of the collapse of supermassive stars to supermassive black holes (SMBHs). By three-dimensional...
astro-ph_HE
2D radiation-hydrodynamic simulations of supernova ejecta with a central power source: We present the results of two-dimensional radiation-hydrodynamic simulations of expanding supernova ejecta with a central energy source. As suggested in previous multi-dimensional hydrodynamic simulations, a sufficiently powerful c...
astro-ph_HE
Neutrino and cosmic-ray emission from multiple internal shocks in gamma-ray bursts: Gamma-ray bursts are short-lived, luminous explosions at cosmological distances, thought to originate from relativistic jets launched at the deaths of massive stars. They are among the prime candidates to produce the observed cosmic r...
astro-ph_HE
Uncloaking hidden repeating fast radio bursts with unsupervised machine learning: The origins of fast radio bursts (FRBs), astronomical transients with millisecond timescales, remain unknown. One of the difficulties stems from the possibility that observed FRBs could be heterogeneous in origin; as some of them have b...
astro-ph_HE
A statistical analysis of the "heartbeat" behaviour of GRS 1915+105: GRS 1915+105 has been active for more than 26 years since it was discovered in 1992. There are hundreds of RXTE pointed observations on this source, and the quasi-regular flares with a slow rise and a sharp decrease (i.e. the "heartbeat" state) were r...
astro-ph_HE
Subphotospheric emission from short gamma-ray bursts: Protons mold the multi-messenger signals: The origin of the observed Band-like photon spectrum in short gamma-ray bursts (sGRBs) is a long-standing mystery. We carry out the first general relativistic magnetohydrodynamic simulation of a sGRB jet with initial magne...
astro-ph_HE
TRAPUM discovery of thirteen new pulsars in NGC 1851 using MeerKAT: We report the discovery of 13 new pulsars in the globular cluster NGC 1851 by the TRAPUM Large Survey Project using the MeerKAT radio telescope. The discoveries consist of six isolated millisecond pulsars (MSPs) and seven binary pulsars, of which six a...
astro-ph_HE
Disc-corona interaction in the heartbeat state of GRS 1915+105: Timing analysis provides information about the dynamics of matter accreting on to neutron stars and black holes, and hence is crucial for studying the physics of the accretion flow around these objects. It is difficult, however, to associate the different ...
astro-ph_HE
Evidence for gravitational lensing of GRB 200716C: Observationally, there is a small fraction of Gamma-ray bursts (GRBs) with prompt emission observed by Fermi/GBM that are composed of two pulses. Occasionally, the distance to a GRB may be lensed when a high mass astrophysical object resides in the path between the GRB...
astro-ph_HE
An outflow powers the optical rise of the nearby, fast-evolving tidal disruption event AT2019qiz: At 66 Mpc, AT2019qiz is the closest optical tidal disruption event (TDE) to date, with a luminosity intermediate between the bulk of the population and iPTF16fnl. Its proximity allowed a very early detection and triggeri...
astro-ph_HE
Light curves and spectra from off-axis gamma-ray bursts: If gamma-ray burst prompt emission originates at a typical radius, and if material producing the emission moves at relativistic speed, then the variability of the resulting light curve depends on the viewing angle. This is due to the fact that the pulse evolution...
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Seven Years with the Swift Supergiant Fast X-ray Transients Project: Supergiant Fast X-ray Transients (SFXTs) are HMXBs with OB supergiant companions. I review the results of the Swift SFXT Project, which since 2007 has been exploiting Swift's capabilities in a systematic study of SFXTs and supergiant X-ray binaries (S...
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A Genetic Algorithm for Astroparticle Physics Studies: Precision measurements of charged cosmic rays have recently been carried out by space-born (e.g. AMS-02), or ground experiments (e.g. HESS). These measured data are important for the studies of astro-physical phenomena, including supernova remnants, cosmic ray prop...
astro-ph_HE
Optical Counterparts of ULXs and Their Host Environments in NGC 4490/4485: We report the identification of the possible optical counterparts of five out of seven Ultraluminous X-ray Sources (ULXs) in NGC 4490/4485 galaxy pair. Using archival Hubble Space Telescope ({\it HST}) imaging data, we identified a single opti...
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Radio WISSH: tuning on the most luminous quasars in the Universe: In the past years, the results obtained by the WISSH quasar project provided a novel general picture on the distinctive multi-band properties of hyper-luminous ($L_{bol}>10^{47}$ erg/s) quasars at high redshift (z$\sim$2-4), unveiling interesting relatio...
astro-ph_HE
Contribution to the Extragalactic Gamma-ray Background from the Cascades of Very-high Energy Gamma Rays: As very-high--energy photons propagate through the extragalactic background light (EBL), they interact with the soft photons and initiate electromagnetic cascades of lower energy photons and electrons. The collect...
astro-ph_HE
A young SNR illuminating nearby Molecular Clouds with cosmic rays: The Supernova Remnant (SNR) HESS J1731-347 displays strong non-thermal TeV gamma-ray and X-ray emission, thus the object is at present time accelerating particles to very high energies. A distinctive feature of this young SNR is the nearby (~30 pc in pr...
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SN 2015an: a normal luminosity type II supernova with low expansion velocity at early phases: We present the photometry and spectroscopy of SN 2015an, a Type II Supernova (SN) in IC 2367. The recombination phase of the SN lasts up to $\sim$120 d, with a decline rate of 1.24 mag/100d, higher than the typical SNe IIP. ...
astro-ph_HE
Early-time VLA observations and broad-band afterglow analysis of the Fermi-LAT detected GRB 130907A: We present multi-wavelength observations of the hyper-energetic gamma-ray burst (GRB) 130907A, a Swift-discovered burst with early radio observations starting at $\approx 4$ hr after the $\gamma$-ray trigger. GRB 1309...
astro-ph_HE
Fornax A, Centaurus A and other radio galaxies as sources of ultra-high energy cosmic rays: The origin of ultra-high energy cosmic rays (UHECRs) is still unknown. It has recently been proposed that UHECR anisotropies can be attributed to starburst galaxies or active galactic nuclei. We suggest that the latter is more...
astro-ph_HE
Gamma Ray Signal from the Pulsar Wind in the Binary Pulsar system PSR B1259-63/LS2883: Binary pulsar systems emit potentially detectable components of gamma ray emission due to Comptonization of the optical radiation of the companion star by relativistic electrons of the pulsar wind, both before and after termination...
astro-ph_HE
First observation of PeV-energy neutrinos with IceCube: We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04 $\pm$ 0.16 and 1.14 $\pm$ 0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with f...
astro-ph_HE
Properties of neutrino transfer in a deformed remnant of neutron star merger: We study properties of neutrino transfer in a remnant of neutron star merger, consisting of a massive neutron star and a surrounding torus. We perform numerical simulations of the neutrino transfer by solving the Boltzmann equation with mom...
astro-ph_HE
Investigation of the particle-particle interaction effects in the cosmic Zevatron based on cyclotron auto-resonance by particle-in-cell simulations: Cyclotron autoresonance acceleration has been recently advanced as a potential mechanism for accelerating nuclei to ZeV energies (1 ZeV = $10^{21}$ eV). All results have...
astro-ph_HE
Search for Tens of MeV Neutrinos associated with Gamma-Ray Bursts in Super-Kamiokande: A search for neutrinos produced in coincidence with Gamma-Ray Bursts(GRB) was conducted with the Super-Kamiokande (SK) detector. Between December 2008 and March 2017, the Gamma-ray Coordinates Network recorded 2208 GRBs that occurr...
astro-ph_HE
On the Particle Acceleration Mechanisms in a Double Radio Relic Galaxy Cluster, Abell 1240: We present a 368 ks deep Chandra observation of Abell~1240, a binary merging galaxy cluster at a redshift of 0.195 with two Brightest Cluster Galaxies (BCGs) may have passed each other 0.3 Gyr ago. Building upon previous inves...
astro-ph_HE
Different behaviors of wavelet results for type-B and type-C QPOs of MAXI J1535-571 based on NICER data: Wavelet analysis, in addition to power density spectra, is another method to study the quasi-periodic signals in the light curves, but has been rarely used in black hole X-ray transients. We performed wavelet anal...
astro-ph_HE
Non-Maxwellian electron distributions in clusters of galaxies: Thermal X-ray spectra of clusters of galaxies and other sources are commonly calculated assuming Maxwellian electron distributions. There are situations where this approximation is not valid, for instance near interfaces of hot and cold gas and near shocks....
astro-ph_HE
A Compton-thin Solution for the Suzaku X-ray Spectrum of the Seyfert 2 Galaxy Mkn 3: Mkn 3 is a Seyfert 2 galaxy that is widely regarded as an exemplary Compton-thick AGN. We study the Suzaku X-ray spectrum using models of the X-ray reprocessor that self-consistently account for the Fe K$\alpha$ fluorescent emission ...
astro-ph_HE