23 research outputs found
Broadband X-ray properties of black holes GRS 1758-258 and 1E 1740.7-2942: AstroSat and NuSTAR results
We present the results on broadband X-ray properties of persistent black hole
binaries GRS 1758258 and 1E 1740.72942 using AstroSat, NuSTAR and
Swift-XRT observations carried out during 20162022. We perform spectral
modeling of both sources after eliminating the contamination in their
\textit{LAXPC} spectra from nearby X-ray sources. Preliminary spectral
modelling using Comptonization and line emission ( 6.4 keV) models
suggest that GRS 1758258 occupies both dim-soft state (
keV, , of Eddington luminosity L) and hard
state (, =445 keV, =15 % L)
that requires a multi-colour disc blackbody model ( keV)
occasionally. 1E 1740.72942 instead is found only in hard state
(=1.672.32, =516 keV, =12 % L).
Reflection properties of both sources are studied by applying relativistic
reflection model RELXILL to the broadband spectra. Our results from
\textit{AstroSat} and \textit{NuSTAR} consistently unveiled the presence of a
Comptonizing region along with an ionized reflection region (ionization
parameter =2.73.8 and 2.74.7 erg cm s in GRS 1758258
and 1E 1740.72942 respectively) in both sources. Reflection modeling
revealed GRS 1758258 to have a high metal abundance
( times solar metal abundance) and inclination angle
() of . In case of 1E 1740.72942, is constrained to
be . Finally, we discuss the implication of our findings in the
context of accretion dynamics by comparing our results with the previous
studies.Comment: Accepted for publication in MNRA
Large Area X-ray Proportional Counter (LAXPC) in Orbit Performance : Calibration, background, analysis software
The Large Area X-ray Proportional Counter (LAXPC) instrument on-board
AstroSat has three nominally identical detectors for timing and spectral
studies in the energy range of 3--80 keV. The performance of these detectors
during the five years after the launch of AstroSat is described. Currently,
only one of the detector is working nominally. The variation in pressure,
energy resolution, gain and background with time are discussed. The
capabilities and limitations of the instrument are described. A brief account
of available analysis software is also provided.Comment: Accepted for publication in JA