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Indications of an unexpected signal associated with the GW170817 binary
neutron star inspiral: We report experimental evidence at the 2.5$\sigma$ level for an unexpected
signal associated with the GW170817 binary neutron star inspiral. This evidence
derives from a laboratory experiment simultaneously measuring the $\... | astro-ph_HE |
X-ray Characteristics of NGC 3516: A View through the Complex Absorber: We consider new Suzaku data for NGC 3516 taken during 2009, along with other
recent X-ray observations of the source. The cumulative characteristics of NGC
3516 cannot be explained without invoking changes in the line-of-sight
absorption. Contrary ... | astro-ph_HE |
Analysis of Reaction-Diffusion Systems for Flame Capturing in Type Ia
Supernova Simulations: We present a study of numerical behavior of a thickened flame used in Flame
Capturing (FC, Khokhlov (1995)) for tracking thin unresolved physical flames in
deflagration simulations. We develop a steady-state procedure for cal... | 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 |
A novel scenario for the possible X-ray line feature at ~3.5 keV: Charge
exchange with bare sulfur ions: Motivated by recent claims of a compelling ~3.5 keV emission line from nearby
galaxies and galaxy clusters, we investigate a novel plasma model incorporating
a charge exchange component obtained from theoretical s... | astro-ph_HE |
The Peculiar Bursting Nature of CP Pup: The classical nova CP Puppis has been observed to have particularly puzzling
and peculiar properties. In particular, this classical nova displays occasional
bursts in its long-term ASAS-SN light curve. Here we report on 5 sectors of
TESS data displaying 2 of these rapid bursts, l... | astro-ph_HE |
Redback: A Bayesian inference software package for electromagnetic
transients: Fulfilling the rich promise of rapid advances in time-domain astronomy is
only possible through confronting our observations with physical models and
extracting the parameters that best describe what we see. Here, we introduce
{\sc Redback... | astro-ph_HE |
A theoretical color-velocity correlation for supernovae associated with
gamma-ray bursts: We carry out the first multi-dimensional radiative transfer calculations to
simultaneously compute synthetic spectra and light curves for models of
supernovae driven by fast bipolar outflows. These allow us to make
self-consiste... | astro-ph_HE |
Evidence of jet induced optical microvariability in radio-loud Narrow
Line Seyfert 1 Galaxies: To quantify the role of radio jets for Intra-Night Optical Variability (INOV)
in Radio-Loud Narrow-Line Seyfert 1 (RLNLSy1) galaxies, we report the first
systematic comparative INOV study of 23 RLNLSy1 galaxies, with 15 RLN... | astro-ph_HE |
On the paucity of Fast Radio Bursts at low Galactic latitudes: We examine the effect of Galactic diffractive interstellar scintillation as a
means of explaining the reported deficit of Fast Radio Burst (FRB) detections
at low Galactic latitude. We model the unknown underlying FRB flux density
distribution as a power la... | astro-ph_HE |
The smooth cyclotron line in Her X-1 as seen with NuSTAR: Her X-1, one of the brightest and best studied X-ray binaries, shows a
cyclotron resonant scattering feature (CRSF) near 37 keV. This makes it an
ideal target for detailed study with the Nuclear Spectroscopic Telescope Array
(NuSTAR), taking advantage of its exc... | astro-ph_HE |
Constraints on Axion-like Particles from a Hard $X$-ray Observation of
Betelgeuse: We use the first observation of Betelgeuse in hard $X$-rays to perform a
novel search for axion-like particles (ALPs). Betelgeuse is not expected to be
a standard source of $X$-rays, but light ALPs produced in the stellar core
could be... | astro-ph_HE |
Using radial velocities to reveal black holes in binaries: a test case: Aims. Large radial velocity variations in the LAMOST spectra of giant stars
have been used to infer the presence of unseen companions. Some of them have
been proposed as possible black hole candidates. We test this selection by
investigating the cl... | astro-ph_HE |
X-ray counterpart candidates for six new $γ$-ray pulsars: Using archival X-ray data we have found point-like X-ray counterpart
candidates positionally coincident with six $\gamma$-ray pulsars discovered
recently in the Fermi Gamma-ray Space Telescope data by the Einstein@Home
project. The candidates for PSRs J0002$+$62... | astro-ph_HE |
AMS02 results support the secondary origin of cosmic ray positrons: We show that the recent AMS02 positron fraction measurement is consistent
with a secondary origin for positrons, and does not require additional primary
sources such as pulsars or dark matter. The measured positron fraction at high
energy saturates the... | astro-ph_HE |
An in-depth investigation of 11 pulsars discovered by FAST: We present timing solutions and analyses of 11 pulsars discovered by the
Five-hundred-meter Aperture Spherical radio Telescope (FAST). These pulsars
were discovered using an ultra-wide bandwidth receiver in drift-scan
observations made during the commissioning... | astro-ph_HE |
Disentangling Instrumental Features of the 130 GeV Fermi Line: We study the instrumental features of photons from the peak observed at
$E_\gamma=130$ GeV in the spectrum of Fermi-LAT data. We use the {\sc sPlots}
algorithm to reconstruct -- seperately for the photons in the peak and for
background photons -- the distri... | astro-ph_HE |
Self-consistent neutrino and UHE cosmic ray spectra from Mrk 421: We examine the neutrino and cosmic ray spectra resulting from two models of
fitting the spectral energy distribution (SED) of the blazar Mrk~421 using a
self-consistent leptohadronic code. The $\gamma$-ray emission is attributed to
either synchrotron rad... | astro-ph_HE |
Neutrino-driven massive stellar explosions in 3D fostered by magnetic
fields via turbulent $α$-effect: We investigate the influence of magnetic field amplification on the
core-collapse supernovae in highly magnetized progenitors through
three-dimensional simulations. By considering rotating models, we observe a
stron... | astro-ph_HE |
A systematic study of magnetar-powered hydrogen-rich supernovae: Context: It has been suggested that some supernovae (SNe) may be powered by a
magnetar formed at the moment of the explosion. While this scenario has mostly
been applied to hydrogen-free events, it may be possible also for hydrogen-rich
objects. Aims: We ... | astro-ph_HE |
Self-similar structure of a hot magnetized flow with thermal conduction: We have explored the structure of hot magnetized accretion flow with thermal
conduction. The importance of thermal conduction in hot accretion flows has
been confirmed by observations of the hot gas surrounding Sgr $A^*$ and a few
other nearby gal... | astro-ph_HE |
A combined timing/spectral study of IRAS 13224-3809 using XMM-Newton
data: We present the results from an X-ray variability study of IRAS 13224-3809.
This is probably the best source for X-ray reverberation studies since it is
X-ray bright, extremely variable, and it has been extensively observed with
XMM-Newton. We ... | astro-ph_HE |
Time-dependent Modeling of Pulsar Wind Nebulae: A spatially independent model that calculates the time evolution of the
electron spectrum in a spherically expanding pulsar wind nebula (PWN) is
presented, allowing one to make broadband predictions for the PWN's non-thermal
radiation. The source spectrum of electrons inj... | astro-ph_HE |
A search for ultra high energy neutrinos from TXS 0506+056 using the
Pierre Auger Observatory: Results of a search for ultra-high-energy neutrinos with the Pierre Auger
Observatory from the direction of the blazar TXS 0506+056 are presented. They
were obtained as part of the follow-up that stemmed from the detection ... | astro-ph_HE |
Observable signatures of stellar-mass black holes in active galactic
nuclei: Stellar-mass black holes (BHs) are predicted to be embedded in the disks of
active galactic nuclei (AGN) due to gravitational drag and in-situ star
formation. However, clear evidence for AGN disk-embedded BHs is currently
lacking. Here, as p... | astro-ph_HE |
HAFFET: Hybrid Analytic Flux FittEr for Transients: The progenitors for many types of supernovae (SNe) are still unknown, and an
approach to diagnose their physical origins is to investigate the light curve
brightness and shape of a large set of SNe. However, it is often difficult to
compare and contrast the existing s... | astro-ph_HE |
A millisecond pulsar discovery in a survey of unidentified Fermi
$γ$-ray sources with LOFAR: Using LOFAR, we have performed a very-low-frequency (115-155 MHz) radio
survey for millisecond pulsars (MSPs). The survey targeted 52 unidentified
Fermi $\gamma$-ray sources. Employing a combination of coherent and incoherent... | astro-ph_HE |
An XMM-Newton Study of the Mixed-Morphology Supernova Remnant G346.6-0.2: We present an X-ray imaging and spectroscopic study of the molecular cloud
interacting mixed-morphology (MM) supernova remnant (SNR) G346.6-0.2 using
XMM-Newton. The X-ray spectrum of the remnant is well described by a
recombining plasma that mos... | astro-ph_HE |
A search for VHE counterparts of Galactic Fermi bright sources and MeV
to TeV spectral characterization: Very high-energy (VHE; E>100 GeV) gamma-rays have been detected from a wide
range of astronomical objects, such as pulsar wind nebulae (PWNe), supernova
remnants (SNRs), giant molecular clouds, gamma-ray binaries,... | astro-ph_HE |
Hard X-ray selected giant radio galaxies -- III. The LOFAR view: Giant radio galaxies (GRGs), with extended structures reaching hundreds of
kpc, are among the most spectacular examples of ejection of relativistic plasma
from super-massive black holes. In this work, third of a series, we present LOw
Frequency ARray (LOF... | astro-ph_HE |
Structures in the cosmic ray energy spectra: All the components of cosmic rays have 'structure' in their energy spectra at
some level, ie deviations from a simple power law, and their examination is
relevant to the origin of the particles. Emphasis, here, is placed on the
large-scale structures in the spectra of nuclei... | astro-ph_HE |
Pair-Instability Supernovae in the Local Universe: The discovery of 150 - 300 M$_{\odot}$ stars in the Local Group and
pair-instability supernova candidates at low redshifts has excited interest in
this exotic explosion mechanism. Realistic light curves for pair-instability
supernovae at near-solar metallicities are ke... | astro-ph_HE |
Ultraviolet Diversity of Type Ia Supernovae: Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) probe the
outermost layers of the explosion, and UV spectra of SNe Ia are expected to be
extremely sensitive to differences in progenitor composition and the details of
the explosion. Here we present the first stud... | astro-ph_HE |
Combined Rastall and Rainbow theories of gravity with applications to
neutron stars: The possibility of modifications on general relativity is investigated. We
propose an alternative theory of gravity constructed with the combination of
Rastall and Rainbow theories. The hydrostatic equilibrium equations are
obtained ... | astro-ph_HE |
The broad band spectral variability of MCG-6-30-15 observed by NuSTAR
and XMM-Newton: MCG-6-30-15, at a distance of 37 Mpc (z=0.008), is the archetypical Seyfert 1
galaxy showing very broad Fe K$\alpha$ emission. We present results from a
joint NuSTAR and XMM-Newton observational campaign that, for the first time,
al... | astro-ph_HE |
Gamma-ray emission from PSR J0007+7303 using 7 years of Fermi Large Area
Telescope observations: Based on more than seven years of Fermi Large Area Telescope (LAT) Pass 8
data, we report on a detailed analysis of the bright gamma-ray pulsar (PSR)
J0007+7303. We confirm that PSR J0007+7303 is significantly detected as... | astro-ph_HE |
Formation of the First Two Black Hole-Neutron Star Mergers (GW200115 and
GW200105) from Isolated Binary Evolution: In this work we study the formation of the first two black hole-neutron star
(BHNS) mergers detected in gravitational waves (GW200115 and GW200105) from
massive stars in wide isolated binary systems - th... | astro-ph_HE |
Evidence for Declination Dependence of the Ultrahigh Energy Cosmic Ray
Spectrum in the Northern Hemisphere: Telescope Array (TA) is the largest experiment in the Northern Hemisphere
studying ultrahigh energy cosmic rays. TA measurements of the cosmic ray
spectrum using the surface detector have the best statistical p... | astro-ph_HE |
High Metallicity LGRB Hosts: We present our imaging and spectroscopic observations of the host galaxies of
two dark long bursts with anomalously high metallicities, LGRB 051022 and LGRB
020819B, which in conjunction with another LGRB event with an optical afterglow
comprise the three LGRBs with high metallicity host ga... | astro-ph_HE |
Unexpected emission pattern adds to the enigma of fast radio bursts: Observations of millisecond-long radio bursts from beyond the Milky Way have
revealed a repeat pattern with a roughly 16-day period -- a finding that adds
to the enigma of the origin of these bursts. | astro-ph_HE |
A variable ionized disk wind in MAXI J1803-298 revealed by NICER: We present the results from the NICER observation data of MAXI J1803-298
across the entire 2021 outburst. In the intermediate and soft state, we detect
significant absorption lines at $\sim 7.0$ keV and $\sim 6.7$ keV, arising from
the X-ray disk wind ou... | astro-ph_HE |
Afterglow Observations of Fermi-LAT Gamma-Ray Bursts and the Emerging
Class of Hyper-Energetic Events: We present broadband (radio, optical, and X-ray) light curves and spectra of
the afterglows of four long-duration gamma-ray bursts (GRBs 090323, 090328,
090902B, and 090926A) detected by the Gamma-Ray Burst Monitor ... | astro-ph_HE |
Discovery of the source HESS J1356-645 associated with the young and
energetic PSR J1357-6429: Several newly discovered very-high-energy (VHE; E > 100 GeV) gamma-ray
sources in the Galaxy are thought to be associated with energetic pulsars.
Among them, middle-aged (> 1E+4 yr) systems exhibit large centre-filled VHE
n... | astro-ph_HE |
General relativistic treatment of $f$-mode oscillations of hyperonic
stars: We present a systematic study of $f$-mode oscillations in neutron stars
containing hyperons, extending recent results obtained within the Cowling
approximation to linearized General Relativity. Employing a relativistic mean
field model, we fi... | astro-ph_HE |
Timing and spectral variability of high mass X-ray pulsar GX 301--2 over
orbital phases observed by Insight-HXMT: We report the orbital X-ray variability of high mass X-ray binary (HMXB)
GX301--2. GX301--2 undergone a spin up process in 2018--2020 with the period
evolving from $\sim$ 685 s to 670 s. The energy resolv... | astro-ph_HE |
Exploring the role of X-ray reprocessing and irradiation in the
anomalous bright optical outbursts of A0538-66: In 1981, the Be/X-ray binary (Be/XRB) A0538-66 showed outbursts characterized
by high peak luminosities in the X-ray and optical bands. The optical outbursts
were qualitatively explained as X-ray reprocessi... | astro-ph_HE |
Type Ia supernovae from violent mergers of carbon-oxygen white dwarfs:
polarisation signatures: The violent merger of two carbon-oxygen white dwarfs has been proposed as a
viable progenitor for some Type Ia supernovae. However, it has been argued that
the strong ejecta asymmetries produced by this model might be inco... | astro-ph_HE |
Optical polarization variations in the blazar PKS 1749+096: We report on the variation in the optical polarization of the blazar PKS
1749+096 observed in 2008--2015. The degree of polarization (PD) tends to
increase in short flares having a time-scale of a few days. The object favors a
polarization angle (PA) of $40^\c... | astro-ph_HE |
A new universal cosmic-ray knee near the magnetic rigidity 10 TV with
the NUCLEON space observatory: Data from the NUCLEON space observatory give a strong indication of the
existence of a new universal cosmic ray "knee", which is observed in all groups
of nuclei, including heavy nuclei, near a magnetic rigidity of ab... | astro-ph_HE |
How, where and when do cosmic rays reach ultrahigh energies?: Understanding the origins of ultrahigh energy cosmic rays (UHECRs) - which
reach energies in excess of $10^{20}~{\rm eV}$ - stretches particle
acceleration physics to its very limits. In this review, we discuss how such
energies can be reached, using general... | astro-ph_HE |
eROSITA Science Book: Mapping the Structure of the Energetic Universe: eROSITA is the primary instrument on the Russian SRG mission. In the first
four years of scientific operation after its launch, foreseen for 2014, it will
perform a deep survey of the entire X-ray sky. In the soft X-ray band (0.5-2
keV), this will b... | astro-ph_HE |
Investigation of Dense Gas Towards Relativistic Outflow Sources: We probe the interstellar medium towards the objects Circinus X-1, a low-mass
X-ray binary with relativistic jets; and the highly energetic Westerlund 2
stellar cluster, which is located towards TeV gamma-ray emission and
interesting arc- and jet-like fea... | astro-ph_HE |
Dark matter in the solar system I: The distribution function of WIMPs at
the Earth from solar capture: The next generation of dark matter (DM) direct detection experiments and
neutrino telescopes will probe large swaths of dark matter parameter space. In
order to interpret the signals in these experiments, it is nece... | astro-ph_HE |
Predictions for the Rates of Compact Binary Coalescences Observable by
Ground-based Gravitational-wave Detectors: We present an up-to-date, comprehensive summary of the rates for all types of
compact binary coalescence sources detectable by the Initial and Advanced
versions of the ground-based gravitational-wave dete... | astro-ph_HE |
Tilted black hole accretion disc models of Sagittarius A*: time-variable
millimetre to near-infrared emission: High-resolution, multi-wavelength, and time-domain observations of the
Galactic centre black hole candidate, Sgr A*, allow for a direct test of
contemporary accretion theory. To date, all models have assumed... | astro-ph_HE |
Relations Between Neutron-Star Parameters in the Hartle-Thorne
Approximation: Using stellar structure calculations in the Hartle-Thorne approximation, we
derive analytic expressions connecting the ellipticity of the stellar surface
to the compactness, the spin angular momentum, and the quadrupole moment of the
spacet... | astro-ph_HE |
Free motion around black holes with discs or rings: between
integrability and chaos -- V: Complete integrability of geodesic motion, the well known feature of the
fields of isolated stationary black holes, can easily be "spoilt" by the
presence of some additional source (even if highly symmetric). In previous
papers,... | astro-ph_HE |
Kinematics of the jet in M87 on scales of 100 -- 1000 Schwarzschild
radii: Very long baseline interferometry (VLBI) imaging of radio emission from
extragalactic jets provides a unique probe of physical mechanisms governing the
launching, acceleration, and collimation of relativistic outflows. The
two-dimensional stru... | astro-ph_HE |
Radial diffusion in corotating magnetosphere of Pulsar PSR J0737-3039B: Rich observational phenomenology associated with Pulsar B in PSR
J0737$-$3039A/B system resembles in many respects phenomena observed in the
Earth and Jupiter magnetospheres, originating due to the wind-magnetosphere
interaction. We consider partic... | astro-ph_HE |
News from the very-high-energy sky seen with H.E.S.S: The H.E.S.S. experiment, the largest Cherenkov telescope array to date, has
been observing the sky at TeV energies for the past 16 years. Its location in
the Southern hemisphere provides H.E.S.S. with equally good access to Galactic
and extra-galactic sources. The f... | astro-ph_HE |
Detecting Gravitational-waves from Extreme Mass Ratio Inspirals using
Convolutional Neural Networks: Extreme mass ratio inspirals (EMRIs) are among the most interesting
gravitational wave (GW) sources for space-borne GW detectors. However,
successful GW data analysis remains challenging due to many issues, ranging
fr... | astro-ph_HE |
A numerical approach to the non-uniqueness problem of cosmic ray
two-fluid equations at shocks: Cosmic rays (CRs) are frequently modeled as an additional fluid in
hydrodynamic (HD) and magnetohydrodynamic (MHD) simulations of astrophysical
flows. The standard CR two-fluid model is described in terms of three
conserva... | astro-ph_HE |
A Luminous Be+White Dwarf Supersoft Source in the Wing of the SMC: MAXI
J0158-744: We present a multi-wavelength analysis of the very fast X-ray transient MAXI
J0158-744, which was detected by MAXI/GSC on 2011 November 11. The subsequent
exponential decline of the X-ray flux was followed with Swift observations, all
... | astro-ph_HE |
Collective baryon decay and gravitational collapse: While it is widely believed that the gravitational collapse of a sufficiently
large mass will lead to a density singularity and an event horizon, we propose
that this never happens when quantum effects are taken into account. In
particular, we propose that when the co... | astro-ph_HE |
Updating the orbital ephemeris of the dipping source XB 1254-690 and the
distance to the source: XB 1254-690 is a dipping low mass X-ray binary system hosting a neutron star
and showing type I X-ray bursts. We aim at obtaining more accurate orbital
ephemeris and at constraining the orbital period derivative of the sy... | astro-ph_HE |
Hidden Hearts of Neutrino Active Galaxies: Recent multimessenger studies have provided evidence for high-energy neutrino
sources that are opaque to GeV-TeV gamma rays. We present model-independent
studies on the connection between neutrinos and gamma rays in the active galaxy
NGC 1068, and find that the neutrinos most ... | astro-ph_HE |
Accreting Millisecond X-Ray Pulsars: Accreting Millisecond X-Ray Pulsars (AMXPs) are astrophysical laboratories
without parallel in the study of extreme physics. In this chapter we review the
past fifteen years of discoveries in the field. We summarize the observations
of the fifteen known AMXPs, with a particular emph... | astro-ph_HE |
The progenitor of binary millisecond radio pulsar PSR J1713+0747
(Research Note): PSR J1713+0747 is a binary system comprising millisecond radio pulsar with a
spin period of 4.57 ms, and a low-mass white dwarf (WD) companion orbiting the
pulsar with a period of 67.8 days. Using the general relativistic Shapiro
delay,... | astro-ph_HE |
Deriving fundamental parameters of millisecond pulsars via AIC in white
dwarfs: We present a study of the observational properties of Millisecond Pulsars
(MSPs) by way of their magnetic fields, spin periods and masses. These
measurements are derived through the scenario of Accretion Induced Collapse
(AIC) of white dw... | astro-ph_HE |
PS1-14bj: A Hydrogen-Poor Superluminous Supernova With a Long Rise and
Slow Decay: We present photometry and spectroscopy of PS1-14bj, a hydrogen-poor
superluminous supernova (SLSN) at redshift $z=0.5215$ discovered in the last
months of the Pan-STARRS1 Medium Deep Survey. PS1-14bj stands out by its
extremely slow ev... | astro-ph_HE |
Particle acceleration in relativistic turbulence: A theoretical
appraisal: We discuss the physics of stochastic particle acceleration in relativistic
magnetohydrodynamic (MHD) turbulence, combining numerical simulations of
test-particle acceleration in synthetic wave turbulence spectra with detailed
analytical estima... | astro-ph_HE |
About the physical nature of some peculiarities of the primary cosmic
radiation nuclei and gamma quanta spectra: About 20 years ago we published the data concerning some peculiarities of the
behavior of cosmic radiation EAS hadron component spectra. The results pointed
to the possible existence in the interstellar sp... | astro-ph_HE |
Intra-Night Optical Variability Monitoring of Fermi Blazars: First
Results from 1.3 m J C Bhattacharya Telescope: We report the first results obtained from our campaign to characterize the
intranight-optical variability (INOV) properties of {\it Fermi}~detected
blazars, using the observations from the recently commis... | astro-ph_HE |
First Multi-wavelength Campaign on the Gamma-ray-loud Active Galaxy IC
310: The extragalactic VHE gamma-ray sky is rich in blazars. These are jetted
active galactic nuclei viewed at a small angle to the line-of-sight. Only a
handful of objects viewed at a larger angle are known so far to emit above 100
GeV. Multi-wav... | astro-ph_HE |
Pevatron at the Galactic Center: Multi-Wavelength Signatures from
Millisecond Pulsars: Diffuse TeV emission has been observed by H.E.S.S. in the Galactic Center
region, in addition to the GeV gamma rays observed by Fermi. We propose that a
population of unresolved millisecond pulsars located around the Galactic
Cente... | astro-ph_HE |
Ne X X-ray Emission due to Charge Exchange in M82: Recent X-ray observations of star-forming galaxies such as M82 have shown the
Ly beta/Ly alpha line ratio of Ne X to be in excess of predictions for thermal
electron impact excitation. Here we demonstrate that the observed line ratio
may be due to charge exchange and c... | astro-ph_HE |
Neutrinos from Choked Jets Accompanied by Type-II Supernovae: The origin of the IceCube neutrinos is still an open question. Upper limits
from diffuse gamma-ray observations suggest that the neutrino sources are
either distant or hidden from gamma-ray observations. It is possible that the
neutrinos are produced in jets... | astro-ph_HE |
Recent multi-wavelength campaigns in the Fermi-GST era: Since 2008 the Fermi/LAT instrument has delivered highly time-resolved
gamma-ray spectra and detailed variability curves for a steadily increasing
number of AGN. For detailed AGN studies the Fermi/LAT data have to be combined
with, and accompanied by, dedicated gr... | astro-ph_HE |
Pair Production in Low Luminosity Galactic Nuclei: Electron-positron pairs may be produced near accreting black holes by a
variety of physical processes, and the resulting pair plasma may be accelerated
and collimated into a relativistic jet. Here we use a self-consistent dynamical
and radiative model to investigate pa... | astro-ph_HE |
The blazar sequence 2.0: I discuss the spectral energy distribution (SED) of all blazars with redshift
detected by the {\it Fermi} satellite and listed in the 3LAC catalog. I will
update the so called "blazar sequence" from the phenomenological point of view,
with no theory or modelling. I will show that: i) pure data ... | astro-ph_HE |
Measuring the Spins of Accreting Black Holes: A typical galaxy is thought to contain tens of millions of stellar-mass black
holes, the collapsed remnants of once massive stars, and a single nuclear
supermassive black hole. Both classes of black holes accrete gas from their
environments. The accreting gas forms a flatte... | astro-ph_HE |
Inferring the core-collapse supernova explosion mechanism with
three-dimensional gravitational-wave simulations: A detection of a core-collapse supernova signal with an Advanced LIGO and
Virgo gravitational-wave detector network will allow us to measure
astrophysical parameters of the source. In real advanced gravita... | astro-ph_HE |
A New Transient Ultraluminous X-ray Source in NGC 7090: We report on the discovery of a new, transient ultraluminous X-ray source
(ULX) in the galaxy NGC 7090. This new ULX, which we refer to as NGC 7090 ULX3,
was discovered via monitoring with $Swift$ during 2019-20, and to date has
exhibited a peak luminosity of $L_{... | astro-ph_HE |
Jet Launching from Merging Magnetized Binary Neutron Stars with
Realistic Equations of State: We perform general relativistic, magnetohydrodynamic (GRMHD) simulations of
binary neutron stars in quasi-circular orbit that merge and undergo delayed or
prompt collapse to a black hole (BH). The stars are irrotational and ... | astro-ph_HE |
Black hole spin of Cyg X-1 determined from the softest state ever
observed: We show the softest ever spectrum from Cyg~X-1, detected in 2013 with Suzaku.
This has the weakest high energy Compton tail ever seen from this object, so
should give the cleanest view of the underlying disk spectrum, and hence the
best deter... | astro-ph_HE |
A general relativistic model of accretion disks with coronae surrounding
Kerr black holes: We calculate the structure of a standard accretion disk with corona
surrounding a massive Kerr black hole in general relativistic frame, in which
the corona is assumed to be heated by the reconnection of the strongly buoyant
ma... | astro-ph_HE |
Multifrequency Variability and Correlations from Extensive Observing
Campaigns of Mkn 421 and Mkn 501 in 2009: We are performing an unprecedentedly long and dense monitoring of the
multi-frequency (radio to TeV) emission from the classical TeV blazars Mkn 421
and Mkn 501. These objects are among the brightest X-ray/T... | astro-ph_HE |
Magnetically Advected Winds: Observations of X-ray absorption lines in magnetically driven disk winds
around black hole binaries and active galactic nuclei yield a universal radial
density profile rho proportional to r^{-1.2} in the wind. This is in
disagreement with the standard Blandford & Payne profile rho_BP propor... | astro-ph_HE |
5.5 years multi-wavelength variability of Mrk 421: evidences of leptonic
emission from the radio to TeV: Mrk 421 is a high-synchrotron-peaked blazar featuring bright and persistent
GeV and TeV emission. We use the longest and densest ongoing unbiased observing
campaign obtained at TeV and GeV energies during 5.5 year... | astro-ph_HE |
Investigating High Mass X-ray Binaries at hard X-rays with INTEGRAL: The INTEGRAL archive developed at INAF-IASF Milano with the available public
observations from late 2002 to 2016 is investigated to extract the X-ray
properties of 58 High Mass X-ray Binaries (HMXBs). This sample consists of
sources hosting either a B... | astro-ph_HE |
PHEMTO : Polarimetric High Energy Modular Telescope Observatory: With the opening of the X and gamma--ray windows in the sixties, thanks to to
sounding rockets and satellite-borne instruments, extremely energetic and
violent phenomena were discovered and subsequently found to be ubiquitous in
the Universe. Observations... | astro-ph_HE |
Variable jet properties in GRB110721A: Time resolved observations of the
jet photosphere: {\it Fermi Gamma-ray Space Telescope} observations of GRB110721A have
revealed two emission components from the relativistic jet: emission from the
photosphere, peaking at $\sim 100$ keV and a non-thermal component, which peaks
... | astro-ph_HE |
LOFAR Detection of 110-188 MHz Emission and Frequency-Dependent Activity
from FRB 20180916B: FRB 20180916B is a well-studied repeating fast radio burst source. Its
proximity (~150 Mpc), along with detailed studies of the bursts, have revealed
many clues about its nature -- including a 16.3-day periodicity in its
acti... | astro-ph_HE |
Dense matter equation of state for neutron star mergers: In simulations of binary neutron star mergers, the dense matter equation of
state (EOS) is required over wide ranges of density and temperature as well as
under conditions in which neutrinos are trapped, and the effects of magnetic
fields and rotation prevail. He... | astro-ph_HE |
Hall cascades versus instabilities in neutron star magnetic fields: The Hall effect is an important nonlinear mechanism affecting the evolution
of magnetic fields in neutron stars. Studies of the governing equation, both
theoretical and numerical, have shown that the Hall effect proceeds in a
turbulent cascade of energ... | astro-ph_HE |
Suzaku Observation of X-ray Variability in Soft State LMC X-1: This paper reports the results of Suzaku observation of the spectral
variation of the black hole binary LMCX-1 in the soft state. The observationwas
carried out in 2009 from July 21 to 24. the obtained net count rate was
$\sim$30 counts s$^{-1}$ in the 0.5-... | astro-ph_HE |
Observation of TeV Gamma Rays from the Fermi Bright Galactic Sources
with the Tibet Air Shower Array: Using the Tibet-III air shower array, we search for TeV gamma-rays from 27
potential Galactic sources in the early list of bright sources obtained by the
Fermi Large Area Telescope at energies above 100 MeV. Among th... | astro-ph_HE |
Is the 130 GeV Line Real? A Search for Systematics in the Fermi-LAT Data: Our recent claims of a Galactic center feature in Fermi-LAT data at
approximately 130 GeV have prompted an avalanche of papers proposing
explanations ranging from dark matter annihilation to exotic pulsar winds.
Because of the importance of such ... | astro-ph_HE |
Cooling and Instabilities in Colliding Flows: Collisional self-interactions occurring in protostellar jets give rise to
strong shocks, the structure of which can be affected by radiative cooling
within the flow. To study such colliding flows, we use the AstroBEAR AMR code
to conduct hydrodynamic simulations in both one... | astro-ph_HE |
Multiwavelength Study of an X-ray Tidal Disruption Event Candidate in
NGC 5092: We present multiwavelength studies of a transient X-ray source, XMMSL1
J131952.3+225958, associated with the galaxy NGC 5092 at $z=0.023$ detected in
the XMM-Newton SLew survey (XMMSL). The source brightened in the 0.2--2 keV
band by a fa... | astro-ph_HE |
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