Astro arXiv | astro-ph.HE Astro arXiv

A Bayesian approach for torque modelling of BeXRB pulsars with application to super-Eddington accretors by A. S. Karaferias et al. on Wednesday 30 November
In this study we present a method to estimate posterior distributions for
standard accretion torque model parameters and binary orbital parameters for
X-ray binaries using a nested sampling algorithm for Bayesian Parameter
Estimation. We study the spin evolution of two Be X-ray binary systems in the
Magellanic Clouds, RX J0520.5-6932 and RX J0209-7427, during major outbursts,
in which they surpassed the Eddington-limit. Moreover, we apply our method to
the recently discovered Swift J0243.6+6124; the only known Galactic pulsating
ultra-luminous X-ray source. This is an excellent candidate for studying the
disc evolution at super-Eddington accretion rates, for its luminosity span
several orders of magnitude during its outburst, with a maximum $L_{\rm X}$
that exceeded the Eddington limit by a factor of $\sim 10$. Our method, when
applied to RX J0520.5-6932 and RX J0209-7427, is able to identify the more
favourable torque model for each system, while yielding meaningful ranges for
the NS and orbital parameters. Our analysis for Swift J0243.6+6124 illustrates
that, contrary to the standard torque model predictions, the magnetospheric
radius and the Alfv\'en radius are not proportional to each other when
surpassing the Eddington limit. Reported distance estimates of this source
range between 5 and 7 kpc. Smaller distances require non-typical neutron star
properties (i.e. mass and radius) and possibly lower radiative efficiency of
the accretion column.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16079v1

A Catalog of the Highest-Energy Cosmic Rays Recorded During Phase I of Operation of the Pierre Auger Observatory by The Pierre Auger Collaboration et al. on Wednesday 30 November
A catalog containing details of the highest-energy cosmic rays recorded
through the detection of extensive air-showers at the Pierre Auger Observatory
is presented with the aim of opening the data to detailed examination.
Descriptions of the 100 showers created by the highest-energy particles
recorded between 1 January 2004 and 31 December 2020 are given for cosmic rays
that have energies in the range 78 EeV to 166 EeV. Details are also given of a
further nine very-energetic events that have been used in the calibration
procedure adopted to determine the energy of each primary. A sky plot of the
arrival directions of the most energetic particles is shown. No interpretations
of the data are offered.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16020v1

A non-repeating fast radio burst in a dwarf host galaxy by Shivani Bhandari et al. on Wednesday 30 November
We present the discovery of as-of-yet non-repeating Fast Radio Burst (FRB)
with the Australian Square Kilometer Array Pathfinder (ASKAP) as a part of the
Commensal Real-time ASKAP Fast Transients (CRAFT) Survey. FRB 20210117A was
detected at the center frequency of 1271.5 MHz with a dispersion measure (DM)
of $728.95\pm 0.01$ pc cm$^{-3}$. The sub-arcsecond localization of the burst
led to the identification of its host galaxy at a $z=0.214(1)$. Optical
observations reveal the host to be a dwarf galaxy with little on-going star
formation, very different to the dwarf host galaxies of known repeating FRBs
20121102A, and 20190520B. We find an excess DM contribution from the host and
attribute it to the FRB's local environment. We do not find any radio emission
from the FRB site or host galaxy. The low magnetized environment and lack of a
persistent radio source (PRS) indicate that the FRB source is older than those
found in other dwarf host galaxies and establish the diversity of FRB sources
in dwarf galaxy environments. We find our observations to be best described by
the hypernebula model, where FRB is powered by accretion-jet from a
hyper-accreting black hole. Finally, our high-time resolution analysis reveal
burst characteristics similar to those seen in repeating FRBs. We encourage
follow-up observations of FRB 20210117A to establish any repeating nature.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16790v1

A non-repeating fast radio burst in a dwarf host galaxy by Shivani Bhandari et al. on Wednesday 30 November
We present the discovery of as-of-yet non-repeating Fast Radio Burst (FRB)
with the Australian Square Kilometer Array Pathfinder (ASKAP) as a part of the
Commensal Real-time ASKAP Fast Transients (CRAFT) Survey. FRB 20210117A was
detected at the center frequency of 1271.5 MHz with a dispersion measure (DM)
of $728.95\pm 0.01$ pc cm$^{-3}$. The sub-arcsecond localization of the burst
led to the identification of its host galaxy at a $z=0.214(1)$. Optical
observations reveal the host to be a dwarf galaxy with little on-going star
formation, very different to the dwarf host galaxies of known repeating FRBs
20121102A, and 20190520B. We find an excess DM contribution from the host and
attribute it to the FRB's local environment. We do not find any radio emission
from the FRB site or host galaxy. The low magnetized environment and lack of a
persistent radio source (PRS) indicate that the FRB source is older than those
found in other dwarf host galaxies and establish the diversity of FRB sources
in dwarf galaxy environments. We find our observations to be best described by
the hypernebula model, where FRB is powered by accretion-jet from a
hyper-accreting black hole. Finally, our high-time resolution analysis reveal
burst characteristics similar to those seen in repeating FRBs. We encourage
follow-up observations of FRB 20210117A to establish any repeating nature.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16790v1

A very luminous jet from the disruption of a star by a massive black hole by Igor Andreoni et al. on Wednesday 30 November
Tidal disruption events (TDEs) are bursts of electromagnetic energy released
when supermassive black holes (SMBHs) at the centers of galaxies violently
disrupt a star that passes too close. TDEs provide a new window to study
accretion onto SMBHs; in some rare cases, this accretion leads to launching of
a relativistic jet, but the necessary conditions are not fully understood. The
best studied jetted TDE to date is Swift J1644+57, which was discovered in
gamma-rays, but was too obscured by dust to be seen at optical wavelengths.
Here we report the optical discovery of AT2022cmc, a rapidly fading source at
cosmological distance (redshift z=1.19325) whose unique lightcurve transitioned
into a luminous plateau within days. Observations of a bright counterpart at
other wavelengths, including X-rays, sub-millimeter, and radio, supports the
interpretation of AT2022cmc as a jetted TDE containing a synchrotron
"afterglow", likely launched by a SMBH with spin $a \gtrsim 0.3$. Using 4 years
of Zwicky Transient Facility (ZTF) survey data, we calculate a rate of $0.02
^{+ 0.04 }_{- 0.01 }$ Gpc$^{-3}$ yr$^{-1}$ for on-axis jetted TDEs based on the
luminous, fast-fading red component, thus providing a measurement complementary
to the rates derived from X-ray and radio observations. Correcting for the
beaming angle effects, this rate confirms that about 1% of TDEs have
relativistic jets. Optical surveys can use AT2022cmc as a prototype to unveil a
population of jetted TDEs.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16530v1

Anisotropic Photon and Electron Scattering without Ultrarelativistic Approximation by Anderson C. M. Lai et al. on Wednesday 30 November
Interactions between photons and electrons are ubiquitous in astrophysics.
Photons can be down scattered (Compton scattering) or up scattered (inverse
Compton scattering) by moving electrons. Inverse Compton scattering, in
particular, is an essential process for the production of astrophysical gamma
rays. Computations of inverse Compton emission typically adopts an isotropic or
an ultrarelativistic assumption to simplify the calculation, which makes them
unable to broadcast the formula to the whole phase space of source particles.
In view of this, we develop a numerical scheme to compute the interactions
between anisotropic photons and electrons without taking ultrarelativistic
approximations. Compared to the ultrarelativistic limit, our exact results show
major deviations when target photons are down scattered or when they possess
energy comparable to source electrons. We also consider two test cases of
high-energy inverse Compton emission to validate our results in the
ultrarelativistic limit. In general, our formalism can be applied to cases of
anisotropic electron-photon scattering in various energy regimes, and for
computing the polarizations of the scattered photons.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.15691v1