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An imperfect double: probing the physical origin of the low-frequency
QPO and its harmonic in black hole binaries: We extract the spectra of the strong low-frequency quasi-periodic oscillation
(QPO) and its harmonic during the rising phase of an outburst in the black-hole
binary XTE J1550-564. We compare these freque... | astro-ph_HE |
Multi-messenger Observations of Tidal Disruption Events: Using the Zwicky Transient Facility (ZTF) and other observatories, we have
identified three candidate Tidal Disruption Events (TDEs) in spatial and
temporal coincidence with high-energy neutrinos detected by IceCube: AT2019dsg,
AT2019fdr and AT2019aalc. All three... | astro-ph_HE |
Binary Neutron Star Mergers and Short Gamma-Ray Bursts: Effects of
Magnetic Field Orientation, Equation of State, and Mass Ratio: We present fully GRMHD simulations of the merger of binary neutron star (BNS)
systems. We consider BNSs producing a hypermassive neutron star (HMNS) that
collapses to a spinning black hole... | astro-ph_HE |
An independent determination of the distance to supernova SN 1987A by
means of the light echo AT 2019xis: Accurate distance determination to astrophysical objects is essential for the
understanding of their intrinsic brightness and size. The distance to SN 1987A
has been previously measured by the expanding photosphe... | astro-ph_HE |
Anomalous Anisotropies of Cosmic Rays from Turbulent Magnetic Fields: The propagation of cosmic rays (CRs) in turbulent interstellar magnetic
fields is typically described as a spatial diffusion process. This formalism
predicts only a small deviation from an isotropic CR distribution in the form
of a dipole in the dire... | astro-ph_HE |
Formation scenarios and mass-radius relation for neutron stars: Neutron star crust, formed via accretion of matter from a companion in a
low-mass X-ray binary (LMXB), has an equation of state (EOS) stiffer than that
of catalyzed matter. At a given neutron star mass, M, the radius of a star with
an accreted crust is the... | astro-ph_HE |
Telescope Array 10 Year Composition: Estimates of the composition of ultra high energy cosmic rays (UHECRs) can be
inferred by recording the depth of air shower maximum, $X_{\mathrm{max}}$, for
many showers and comparing the distributions to those predicted by Monte Carlo
simulations. Traditionally, UHECR composition h... | astro-ph_HE |
Search for Coincident Gravitational Wave and Long Gamma-Ray Bursts from
4-OGC and the Fermi-GBM/Swift-BAT Catalog: The recent discovery of a kilonova associated with an apparent long-duration
gamma-ray burst has challenged the typical classification that long gamma-ray
bursts originate from the core collapse of massi... | astro-ph_HE |
Resolving the X-ray obscuration in a low flux observation of the quasar
PDS 456: Simultaneous XMM-Newton, NuSTAR and HST observations, performed in March
2017, of the nearby ($z=0.184$) luminous quasar PDS 456 are presented. PDS 456
had a low X-ray flux compared to past observations, where the first of the two
new XM... | astro-ph_HE |
Proton synchrotron, plausible explanation for delayed VHE activity of 3C
279 in 2018: A nearly 11-day delayed very-high-energy(VHE) activity compared to the
Fermi-LAT flare from quasar 3C 279 was reported by H.E.S.S. on 28 January 2018.
3C 279 has long been considered a candidate site for particle acceleration;
hence... | astro-ph_HE |
Properties of unique hard X-ray dips observed from GRS 1915+105 and IGR
J17091-3624 and their implications: We report a comprehensive study on spectral and timing properties of hard
X-ray dips uniquely observed in some so-called variability classes of the
micro-quasars GRS 1915+105 and IGR J17091-3624. These dips are... | astro-ph_HE |
Gamma-Ray Burst observations with Fermi: After seven years of science operation, the Fermi mission has brought great
advances in the study of Gamma-ray Bursts (GRBs). Over 1600 GRBs have been
detected by the Gamma-ray Burst Monitor, and more than 100 of these are also
detected by the Large Area Telescope above 30 MeV. ... | astro-ph_HE |
Strongly Lensed Supermassive Black Hole Binaries as Nanohertz
Gravitational-Wave Sources: Supermassive black hole binary systems (SMBHBs) should be the most powerful
sources of gravitational waves (GWs) in the Universe. Once Pulsar Timing Arrays
(PTAs) detect the stochastic GW background from their cosmic merger hist... | astro-ph_HE |
Properties of Low Luminosity Afterglow Gamma-ray Bursts: Aims: We characterize a sample of Gamma-Ray Bursts with low luminosity X-ray
afterglows (LLA GRBs), and study their properties. Method: We select a sample
consisting of the 12\% faintest X-ray afterglows from the total population of
long GRBs (lGRBs) with known r... | astro-ph_HE |
Neutrino analysis of the September 2010 Crab Nebula flare and
time-integrated constraints on neutrino emission from the Crab using IceCube: We present the results for a search of high-energy muon neutrinos with the
IceCube detector in coincidence with the Crab nebula flare reported on
September 2010 by various experi... | astro-ph_HE |
Properties of intra-cluster low-mass X-ray binaries in Fornax globular
clusters: We present a study of the intra-cluster population of low-mass X-ray binaries
(LMXB) residing in globular clusters (GC) in the central 1 $deg^2$ of the
Fornax galaxy cluster. Differently from previous studies, which were restricted
to th... | astro-ph_HE |
Rapid Infrared Variability of Three Radio-loud Narrow-line Seyfert 1
Galaxies: A View from the Wide-field Infrared Survey Explorer: Using newly released data from the Wide-field Infrared Survey Explorer, we
report the discovery of rapid infrared variability in three radio-loud
narrow-line Seyfert 1 galaxies (NLS1s) s... | astro-ph_HE |
Assessing equation of state-independent relations for neutron stars with
nonparametric models: Relations between neutron star properties that do not depend on the nuclear
equation of state offer insights on neutron star physics and have practical
applications in data analysis. Such relations are obtained by fitting t... | astro-ph_HE |
Very High-Energy ($>$50 GeV) Gamma-ray Flux Variability of Bright Fermi
Blazars: Understanding the high-energy emission processes and variability patterns are
two of the most challenging research problems associated with relativistic
jets. In particular, the long-term (months-to-years) flux variability at very
high e... | astro-ph_HE |
Very Rapid High-Amplitude Gamma-ray Variability in Luminous Blazar PKS
1510-089 Studied with Fermi-LAT: Here we report on the detailed analysis of the gamma-ray light curve of a
luminous blazar PKS1510-089 observed in the GeV range with the Large Area
Telescope (LAT) onboard the Fermi satellite during the period 2011... | astro-ph_HE |
Application of the space-based optical interferometer towards measuring
cosmological distances of quasars: Measuring the quasar distance through joint analysis of spectroastrometry
(SA) and reverberation mapping (RM) observations is a new method for driving
the development of cosmology. In this paper, we carry out de... | astro-ph_HE |
Unexpected late-time temperature increase observed in two neutron star
crust cooling sources -- XTE~J1701-462 and EXO~0748-676: Transient LMXBs that host neutron stars (NSs) provide excellent laboratories
for probing the dense matter physics present in NS crusts. During accretion
outbursts in LMXBs, exothermic reacti... | astro-ph_HE |
Towards a dynamical mass of the ultraluminous X-ray source NGC 5408 X-1: We obtained multi-epoch Very Large Telescope (VLT) optical spectroscopic data
in 2011 and 2012 on the ultraluminous X-ray source (ULX) NGC 5408 X-1. We
confirm that the HeII\lambda4686 line has a broad component with an average
FWHM of v=780\pm64 ... | astro-ph_HE |
On the Diversity of Fallback Rates from Tidal Disruption Events with
Accurate Stellar Structure: The tidal disruption of stars by supermassive black holes (SMBHs) can be used
to probe the SMBH mass function, the properties of individual stars, and
stellar dynamics in galactic nuclei. Upcoming missions will detect tho... | astro-ph_HE |
Spherical configuration of a super-dense hot compact object with
particular EoS: The equation of state (EoS) $P = P (\rho, ...)$ -- pressure as a function of
density and other thermodynamical quantities -- is what generates
particularities of mass--radius distribution $M (R)$ for super--dense compact
stellar bodies, ... | astro-ph_HE |
X-ray/UV/optical variability of NGC 4593 with Swift: Reprocessing of
X-rays by an extended reprocessor: We report the results of intensive X-ray, UV and optical monitoring of the
Seyfert 1 galaxy NGC 4593 with Swift. There is no intrinsic flux-related
spectral change in the the variable components in any band with sm... | astro-ph_HE |
Evidence for powerful winds and the associated reverse shock as the
origin of the Fermi bubbles: The Fermi bubbles are large gamma-ray-emitting structures. They are symmetric
about the Galactic Centre (GC), and their creation is therefore attributed to
intensive energy injection at the GC. In this study, we focus on ... | astro-ph_HE |
Black hole lightning due to particle acceleration at subhorizon scales: Supermassive black holes with masses of millions to billions of solar masses
are commonly found in the centers of galaxies. Astronomers seek to image jet
formation using radio interferometry, but still suffer from insufficient
angular resolution. A... | astro-ph_HE |
Optical and Infrared Photometry of the Nearby SN 2017cbv: On 2017 March 11, the DLT40 Transient Discovery Survey discovered SN 2017cbv
in NGC5643, a Type 2 Seyfert Galaxy in the Lupus Constellation. SN 2017cbv went
on to become a bright Type Ia supernova, with a $V_{max}$ of 11.51 $\pm$ 0.05
mag. We present early time ... | astro-ph_HE |
Rapid spectral transition of the black hole binary V404 Cyg: During the June 2015 outburst of the black hole binary V404 Cyg, rapid
changes in the X-ray brightness and spectra were common. The INTEGRAL
monitoring campaign detected spectacular Eddington-limited X-ray flares, but
also rapid variations at much lower flux ... | astro-ph_HE |
Astro 2020 Science White Paper: Cosmic-ray Antinuclei as Messengers for
Dark Matter: The origin of dark matter is a driving question of modern physics. Low-energy
antideuterons provide a "smoking gun" signature of dark matter annihilation or
decay, essentially free of astrophysical background. Low-energy antiprotons ... | astro-ph_HE |
Binary evolution with LOFT: This is a White Paper in support of the mission concept of the Large
Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We
discuss the potential of LOFT for the study of very faint X-ray binaries,
orbital period distribution of black hole X-ray binaries and neutron ... | astro-ph_HE |
Old Data, New Forensics: The First Second of SN 1987A Neutrino Emission: The next Milky Way supernova will be an epochal event in multi-messenger
astronomy, critical to tests of supernovae, neutrinos, and new physics.
Realizing this potential depends on having realistic simulations of core
collapse. We investigate the ... | astro-ph_HE |
Strong Calcium Emission Indicates that the Ultraviolet-Flashing Type Ia
SN 2019yvq was the Result of a Sub-Chandrasekhar Mass Double-Detonation
Explosion: We present nebular spectra of the Type Ia supernova (SN Ia) SN 2019yvq, which
had a bright flash of blue and ultraviolet light after exploding, followed by a
ris... | astro-ph_HE |
Extreme Gravity and Fundamental Physics: Future gravitational-wave observations will enable unprecedented and unique
science in extreme gravity and fundamental physics answering questions about
the nature of dynamical spacetimes, the nature of dark matter and the nature of
compact objects. | astro-ph_HE |
X-ray Polarization of Gamma-Ray Bursts: The degree and the temporal evolution of linear polarization in the prompt
and afterglow emission of gamma-ray bursts is a very robust diagnostic of some
key features of gamma-ray bursts jets and their micro and macro physics. In
this contribution, I review the current status of ... | astro-ph_HE |
Impact of the Cherenkov Telescope Array (CTA) altitude on Dark Matter
searches in the Milky Way Halo: Observations of dwarf galaxies and of the Milky Way halo with current
ground-based Cherenkov telescopes have resulted in interesting limits on the
cross-section for dark matter (DM) self- annihilation for WIMP masses... | astro-ph_HE |
Spectroscopic r-Process Abundance Retrieval for Kilonovae II:
Lanthanides in the Inferred Abundance Patterns of Multi-Component Ejecta from
the GW170817 Kilonova: In kilonovae, freshly-synthesized $r$-process elements imprint features on
optical spectra, as observed in AT2017gfo, the counterpart to the GW170817
bin... | astro-ph_HE |
Multimessenger signal from phase transition of neutron star to quark
star: Aim: To study the multimessenger nature of the signal that can result from
the phase transition of a neutron star to a quark star and their corresponding
astrophysical observations. Methods: The phase transition process is initiated
by the abr... | astro-ph_HE |
Constraining Progenitors of Observed LMXBs Using CARB Magnetic Braking: We present a new method for constraining the mass transfer evolution of low
mass X-ray binaries (LMXBs) - a reverse population synthesis technique. This is
done using the detailed 1D stellar evolution code MESA (Modules for Experiments
in Stellar A... | astro-ph_HE |
Novel dark matter constraints from antiprotons in the light of AMS-02: We evaluate dark matter (DM) limits from cosmic-ray antiproton observations
using the recent precise AMS-02 measurements. We properly take into account
cosmic-ray propagation uncertainties fitting at the same time DM and
propagation parameters, and ... | astro-ph_HE |
Cosmic-ray Antinuclei as Messengers of New Physics: Status and Outlook
for the New Decade: The precise measurement of cosmic-ray antinuclei serves as an important means
for identifying the nature of dark matter and other new astrophysical
phenomena, and could be used with other cosmic-ray species to understand
cosmic... | astro-ph_HE |
A Numerical Model for the Multi-wavelength Lightcurves of PSR J0030+0451: Recent modeling of Neutron Star Interior Composition Explorer(NICER)
observations of the millisecond pulsar PSR J0030+0451 suggests that the
magnetic field of the pulsar is non-dipolar. We construct a magnetic field
configuration where foot point... | astro-ph_HE |
Spheroidal force-free neutron star magnetospheres: Abridged. Fast rotating and self-gravitating astrophysical objects suffer
strong deformations from centrifugal forces. If moreover they are magnetized,
they generate an electromagnetic wave that is perturbed accordingly. When
stellar objects are also surrounded by an i... | astro-ph_HE |
A study of the accretion mechanisms of the High Mass X-ray Binary IGR
J00370+6122: IGR J00370+6122 is a high-mass X-ray binary, of which the primary is a B1 Ib
star, whereas the companion is suggested to be a neutron star by the detection
of 346-s pulsation in one-off 4-ks observation. To better understand the nature... | astro-ph_HE |
A Ray-Tracing Algorithm for Spinning Compact Object Spacetimes with
Arbitrary Quadrupole Moments. II. Neutron Stars: A moderately spinning neutron star acquires an oblate shape and a spacetime
with a significant quadrupole moment. These two properties affect its apparent
surface area for an observer at infinity, as w... | astro-ph_HE |
Possible changes of state and relevant timescales for a neutron star in
LS I +61°303: The properties of the short, energetic bursts recently observed from the
gamma-ray binary LS I +61{\deg}303, are typical of those showed by high
magnetic field neutron stars, and thus provide a strong indication in favor of
a neutro... | astro-ph_HE |
Measurement of Anisotropy and Search for UHECR Sources: Ultra-high energy cosmic rays (UHECRs) are particles, likely protons and/or
nuclei, with energies up to $10^{20}$ eV that are observed through the giant
air showers they produce in the atmosphere. These particles carry the
information on the most extreme phenomena... | astro-ph_HE |
Antiproton Flux in Cosmic Ray Propagation Models with Anisotropic
Diffusion: Recently a cosmic ray propagation model has been introduced, where
anisotropic diffusion is used as a mechanism to allow for $\mathcal{O}(100)$
km/s galactic winds. This model predicts a reduced antiproton background flux,
suggesting an exce... | astro-ph_HE |
On the GeV excess in the diffuse γ-ray emission towards the
Galactic Center: The Fermi-LAT \gamma-ray data have been used to study the morphological and
spectral features of the so-called GeV excess - a diffuse radiation component
recently discovered towards the Galactic centre. We used the likelihood method
to analy... | astro-ph_HE |
Discovery of a jet-like structure with overionized plasma in the SNR
IC443: IC443 is a supernova remnant located in a quite complex environment since it
interacts with nearby clouds. Indications for the presence of overionized
plasma have been found though the possible physical causes of overionization
are still deba... | astro-ph_HE |
Growth of magnetic fields in accreting millisecond pulsars: R-modes can generate strong magnetic fields in the core of accreting
millisecond neutron stars (NSs). The diffusion of these fields outside the core
causes the growth of the external magnetic field and thus it affects the
evolution of the spin down rates $\dot... | astro-ph_HE |
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... | astro-ph_HE |
Joint constraints on the field-cluster mixing fraction, common envelope
efficiency, and globular cluster radii from a population of binary hole
mergers via deep learning: The recent release of the second Gravitational-Wave Transient Catalog
(GWTC-2) has increased significantly the number of known GW events, enablin... | astro-ph_HE |
Multi-wavelength temporal and spectral study of PKS 0402-362: We study the long-term behavior of the bright gamma-ray blazar PKS 0402-362.
Over a span of approximately 12.5 years, from August 2008 to January 2021, we
gathered Fermi-LAT temporal data and identified three distinct periods of
intense $\gamma$-ray activity... | astro-ph_HE |
New limits on the local Lorentz invariance violation of gravity in the
Standard-Model Extension with pulsars: Lorentz Violation (LV) is posited as a possible relic effect of quantum
gravity at low energy scales. The Standard-Model Extension provides an
effective field-theoretic framework for examining possible deviat... | astro-ph_HE |
First 100 ms of a long-lived magnetized neutron star formed in a binary
neutron star merger: The recent multimessenger observation of the short gamma-ray burst (SGRB) GRB
170817A together with the gravitational wave (GW) event GW170817 provides
evidence for the long-standing hypothesis associating SGRBs with binary n... | astro-ph_HE |
Electron capture of strongly screening nuclides $^{56}$Fe, $^{56}$Co,
$^{56}$Ni , $^{56}$Mn ,$^{56}$Cr and $^{56}$V in presupernova: According to the Shell-Model Monte Carlo method, basing on the Random Phase
Approximation and the linear response theory, we carried out an estimation on
electron capture of strongly sc... | astro-ph_HE |
Disentangling the Air Shower Components Using Scintillation and Water
Cherenkov Detectors: We consider a ground array of scintillation and water Cherenkov detectors
with the purpose of determining the muon content of air showers. The different
response characteristics of these two types of detectors to the components... | astro-ph_HE |
Mass Distribution and Maximum Mass of Neutron Stars: Effects of Orbital
Inclination Angle: Matter at ultra-high densities finds a physical realization inside neutron
stars. One key property is their maximum mass, which has far-reaching
implications for astrophysics and the equation of state of ultra dense matter.
In ... | astro-ph_HE |
Interacting Kilonovae: Long-lasting Electromagnetic Counterparts to
Binary Mergers in the Accretion Disks of Active Galactic Nuclei: We investigate the dynamics and electromagnetic (EM) signatures of neutron
star-neutron star (NS-NS) or neutron star-black hole (NS-BH) merger ejecta that
occurs in the accretion disk o... | astro-ph_HE |
The temperature of hot gas halos of early-type galaxies: Recently, the temperature T and luminosity L_X of the hot gas halos of early
type galaxies have been derived with unprecedented accuracy from Chandra data,
for 30 galaxies covering a wider range of galactic luminosity (and central
velocity dispersion sigma_c) tha... | astro-ph_HE |
Probing the dipole of the diffuse gamma-ray background: We measured the dipole of the diffuse $\gamma$-ray background (DGB)
identifying a highly significant time-independent signal coincidental with that
of the Pierre Auger UHECR. The DGB dipole is determined from flux maps in
narrow energy bands constructed from 13 ye... | astro-ph_HE |
About the measurements of the hard X-ray background: We analyze uncertainties in the cosmic X-ray background measurements
performed by the INTEGRAL observatory. We find that the most important effect
limiting the accuracy of the measurements is related to the intrinsic
background variation in detectors. Taking into acc... | astro-ph_HE |
Compact Symmetric Objects -- III Evolution of the High-Luminosity Branch
and a Possible Connection with Tidal Disruption Events: We use a sample of 54 Compact Symmetric Objects (CSOs) to confirm that there
are two unrelated CSO classes: an edge-dimmed, low-luminosity class (CSO~1),
and an edge-brightened, high-lumino... | astro-ph_HE |
Resonance suppression of the r-mode instability in superfluid neutron
stars: Accounting for muons and entrainment: We calculate the finite-temperature r-mode spectrum of a superfluid neutron
star accounting for both muons in the core and the entrainment between neutrons
and protons. We show that the standard perturba... | astro-ph_HE |
Statistical studies of supernova environments: Investigations of the environments of SNe allow statistical constraints to be
made on progenitor properties. We review progress that has been made in this
field. Pixel statistics using tracers of e.g. star formation within galaxies
show differences in the explosion sites o... | astro-ph_HE |
The optical and near-infrared spectrum of the Crab pulsar with X-shooter: Pulsars are well studied all over the electromagnetic spectrum, and the Crab
pulsar may be the most studied object in the sky. Nevertheless, a high-quality
optical to near-infrared spectrum of the Crab or any other pulsar has not been
published t... | astro-ph_HE |
Multiwavelength temporal and spectral study of TeV blazar 1ES 1727+502
during 2014 to 2021: One of the most important questions in blazar physics is the origin of
broadband emission and fast-flux variation. In this work, we studied the
broadband temporal and spectral properties of a TeV blazar 1ES 1727+502 and
explor... | astro-ph_HE |
Search for extended gamma ray emission in Markarian 421 using VERITAS
observations: Very high energy (VHE: >100 GeV) gamma rays coming from AGN can pair-produce
on the intergalactic background light generating an electromagnetic cascade. If
the Intergalactic Magnetic Field (IGMF) is sufficiently strong, this cascade
... | astro-ph_HE |
Enforcing causality in nonrelativistic equations of state at finite
temperature: We present a thermodynamically consistent method by which equations of state
based on nonrelativistic potential models can be modified so that they respect
causality at high densities, both at zero and finite temperature (entropy). We
il... | astro-ph_HE |
Low-Mass X-ray Binaries in Globular Clusters: Puzzles and Solutions: In dense stellar systems, dynamical interactions between objects lead to
frequent formation of exotic stellar objects, unusual binaries, and systems of
higher multiplicity. They are especially important for the formation of low
mass X-ray binaries (LM... | astro-ph_HE |
Mode switching and oscillations in PSR B1828-11: The young pulsar PSR B1828-11 has long been known to show correlated shape
and spin-down changes with timescales of roughly 500 and 250 days, perhaps
associated with large-scale magnetospheric switching. Here we present
multi-hour observations with the Parkes and Green B... | astro-ph_HE |
Multi-frequency VLBI Observations of the M 84 Inner Jet/Counterjet: Observational studies of inner-most regions of the edge-on jets in nearby
active galactic nuclei (AGN) are crucial to understand their kinematics and
morphology. For the inner jet of the nearby low luminosity AGN in M 84, we
present new high-sensitivit... | astro-ph_HE |
Fermi-LAT detection of G118.4+37.0: a supernova remnant in the Galactic
halo seen around the Calvera pulsar: The discovery of a non-thermal radio ring of low surface brightness about one
degree in diameter has been recently reported around the location in the sky of
the Calvera pulsar, at a high Galactic latitude. Th... | astro-ph_HE |
Hydrodynamics of Core-Collapse Supernovae at the Transition to
Explosion. I. Spherical Symmetry: We study the transition to runaway expansion of an initially stalled
core-collapse supernova shock. The neutrino luminosity, mass accretion rate,
and neutrinospheric radius are all treated as free parameters. In spherical... | astro-ph_HE |
A NICER look at the state transitions of the black hole candidate MAXI
J1535-571 during its reflares: The black hole candidate and X-ray binary MAXI J1535-571 was discovered in
September 2017. During the decay of its discovery outburst, and before
returning to quiescence, the source underwent at least four reflaring ... | astro-ph_HE |
Inclination Dependence of The Time-Lag -- Photon-Index Correlation in
BHXRBs and its Explanation with a Simple Jet Model: Recently, we reported an observational correlation between a) the time-lag of
the hard (9 - 15 keV) with respect to the soft (2 - 5 keV) X-ray photons in
black-hole X-ray binaries (BHXRBs) and b) ... | astro-ph_HE |
Superluminal Waves and the Structure of Pulsar Wind Termination Shocks: The termination shock of a pulsar wind is located roughly where the ram
pressure matches that of the surrounding medium. Downstream of the shock, MHD
models of the diffuse nebular emission suggest the plasma is weakly magnetized.
However, the trans... | astro-ph_HE |
Impact of Rastall gravity on mass, radius and sound speed of the pulsar
PSR J0740+6620: Millisecond pulsars are perfect laboratories to test possible matter-geometry
coupling and its physical implications in light of recent Neutron Star Interior
Composition Explorer (NICER) observations. We apply Rastall field equati... | astro-ph_HE |
Identification of an X-ray Pulsar in the BeXRB system IGR J18219$-$1347: We report on observations of the candidate Be/X-ray binary IGR J18219$-$1347
with \textit{Swift}/XRT, \textit{NuSTAR}, and \textit{NICER} during Type-I
outbursts in March and June 2020. Our timing analysis revealed the spin period
of a neutron sta... | astro-ph_HE |
A real-time transient detector and the Living Swift-XRT Point Source
catalogue: We present the Living Swift-XRT Point Source catalogue (LSXPS) and real-time
transient detector. This system allows us for the first time to carry out
low-latency searches for new transient X-ray events fainter than those
available to the... | astro-ph_HE |
SN 2020udy: a SN Iax with strict limits on interaction consistent with a
helium-star companion: Early observations of transient explosions can provide vital clues to their
progenitor origins. In this paper we present the nearby Type Iax (02cx-like)
supernova (SN), SN 2020udy that was discovered within hours ($\sim$7 ... | astro-ph_HE |
On the morphology of outbursts of accreting millisecond X-ray pulsar
Aquila X-1: We present the X-ray light curves of the last two outbursts --2014 & 2016--
of the well known accreting millisecond X-ray pulsar (AMXP) Aquila X-1 using
the monitor of all sky X-ray image (MAXI) observations in the $2-20$ keV band.
After... | astro-ph_HE |
The 450 days X-ray monitoring of the changing-look AGN 1ES 1927+654: 1ES 1927+654 is a nearby active galactic nucleus (AGN) which underwent a
changing-look event in early 2018, developing prominent broad Balmer lines
which were absent in previous observations. We have followed up this object in
the X-rays with an ongoi... | astro-ph_HE |
Modelling the Type Ic SN 2004aw: a Moderately Energetic Explosion of a
Massive C+O Star without a GRB: An analysis of the Type Ic supernova (SN) 2004aw is performed by means of
models of the photospheric and nebular spectra and of the bolometric light
curve. SN2004aw is shown not to be ``broad-lined'', contrary to pr... | astro-ph_HE |
A ring-like accretion structure in M87 connecting its black hole and jet: The nearby radio galaxy M87 is a prime target for studying black hole
accretion and jet formation^{1,2}. Event Horizon Telescope observations of M87
in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was
interpreted as grav... | astro-ph_HE |
Predicting the X-ray polarization of type-2 Seyfert galaxies: Infrared, optical and ultraviolet spectropolarimetric observations have
proven to be ideal tools for the study of the hidden nuclei of type-2 active
galactic nuclei (AGN) and for constraining the composition and morphology of
the sub-parsec scale emission co... | astro-ph_HE |
Oscillation of high-energy neutrinos from choked jets in stellar and
merger ejecta: We present a comprehensive study on oscillation of high-energy neutrinos from
two different environments: blue supergiant progenitors that may harbor
low-power gamma-ray burst (GRB) jets and neutron star merger ejecta that would
be as... | astro-ph_HE |
X-ray line formation in the spectrum of SS 433: The mechanisms for the formation of X-ray lines in the spectrum of SS 433 are
investigated by taking into account the radiative transfer inside the jets. The
results of Monte Carlo numerical simulations are presented. The effect of a
decrease in line intensity due to scat... | astro-ph_HE |
A radio structure resolved at the deca-parsec scale in radio-quiet
quasar PDS 456 with an extremely powerful X-ray outflow: Active galactic nuclei (AGN) accreting at rates close to the Eddington limit
can host radiatively driven mildly relativistic outflows. Some of these X-ray
absorbing but powerful outflows may pro... | astro-ph_HE |
Observations of diffuse fluxes of cosmic neutrinos: In this contribution the current observational results for the diffuse flux
of high-energy astrophysical neutrinos are reviewed. In order to understand the
science implications, the measurements in different detection channels are
discussed and results are compared. T... | astro-ph_HE |
The Compton Spectrometer and Imager: The Compton Spectrometer and Imager (COSI) is a NASA Small Explorer (SMEX)
satellite mission in development with a planned launch in 2027. COSI is a
wide-field gamma-ray telescope designed to survey the entire sky at 0.2-5 MeV.
It provides imaging, spectroscopy, and polarimetry of a... | astro-ph_HE |
Comments on "Imaging Reanalyses of EHT Data": On June 14, 2022, the EHT collaboration (hereafter EHTC) made the web page
(https://eventhorizontelescope.org/blog/imaging-reanalyses-eht-data) with the
title "Imaging Reanalyses of EHT Data," in which they made comments on our
recent Miyoshi et al .2022 published in the As... | astro-ph_HE |
Gamma Ray Lines from a Universal Extra Dimension: Indirect Dark Matter searches are based on the observation of secondary
particles produced by the annihilation or decay of Dark Matter. Among them,
gamma-rays are perhaps the most promising messengers, as they do not suffer
deflection or absorption on Galactic scales, s... | astro-ph_HE |
Estimation of Plasma Parameters in an Accretion Column near the Surface
of Accreting White Dwarfs from Their Flux Variability: We consider the behavior of matter in the accretion column that emerges under
accretion in binary systems near the surface of a white dwarf. The plasma
heated in a standing shock wave near th... | astro-ph_HE |
Application of the MST clustering to the high energy gamma-ray sky. IV -
Blazar candidates found as possible counterparts of photon clusters: We present the results of a cluster search in the Fermi-LAT Pass 8 gamma-ray
sky by means of the Minimum Spanning Tree algorithm, at energies higher than 10
GeV and at Galactic... | astro-ph_HE |
IceCube as a Multi-messenger Follow-up Observatory for Astrophysical
Transients: The recent association between IC-170922A and the blazar TXS0506+056
highlights the importance of real-time observations for identifying possible
astrophysical neutrino sources. Thanks to its near-100\% duty cycle, 4$\pi$
steradian field... | astro-ph_HE |
Cosmic Gamma Ray Bursts: Gamma ray bursts (GRBs) are astronomical phenomena detected at highest
energies. The gamma ray photons carry energies on the order of
mega-electronovolts and arrive to us from the point-like sources that are
uniformly distributed on the sky. A typical burst has a form of a pulse that
lasts for ... | astro-ph_HE |
Multimessenger observations of counterparts to IceCube-190331A: High-energy neutrinos are a promising tool for identifying astrophysical
sources of high and ultra-high energy cosmic rays (UHECR). Prospects of
detecting neutrinos at high energies ($\gtrsim$TeV) from blazars have been
boosted after the recent association... | astro-ph_HE |
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