Time resolved spectroscopy of a GRS 1915+105 flare during its unusual low state using AstroSat

Fuente: arXiv
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Main Authors: Boked, Sajad, Maqbool, Bari, Jithesh, V., Misra, Ranjeev, Iqbal, Naseer, Bhulla, Yashpal
Format: Preprint
Published: 2024
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_version_ 1866913229761937408
author Boked, Sajad
Maqbool, Bari
Jithesh, V.
Misra, Ranjeev
Iqbal, Naseer
Bhulla, Yashpal
author_facet Boked, Sajad
Maqbool, Bari
Jithesh, V.
Misra, Ranjeev
Iqbal, Naseer
Bhulla, Yashpal
contents Since its discovery in 1992, GRS 1915+105 has been among the brightest sources in the X-ray sky. However, in early 2018, it dimmed significantly and has stayed in this faint state ever since. We report on AstroSat and NuSTAR observation of GRS 1915+105 in its unusual low/hard state during 2019 May. We performed time-resolved spectroscopy of the X-ray flares observed in this state and found that the spectra can be fitted well using highly ionised absorption models. We further show that the spectra can also be fitted using a highly relativistic reflection dominated model, where for the lamp post geometry, the X-ray emitting source is always very close to the central black hole. For both interpretations, the flare can be attributed to a change in the intrinsic flux, rather than dramatic variation in the absorption or geometry. These reflection dominated spectra are very similar to the reflection dominated spectra reported for Active Galactic Nuclei in their low flux states.
format Preprint
id arxiv_https___arxiv_org_abs_2402_06569
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Time resolved spectroscopy of a GRS 1915+105 flare during its unusual low state using AstroSat
Boked, Sajad
Maqbool, Bari
Jithesh, V.
Misra, Ranjeev
Iqbal, Naseer
Bhulla, Yashpal
High Energy Astrophysical Phenomena
Since its discovery in 1992, GRS 1915+105 has been among the brightest sources in the X-ray sky. However, in early 2018, it dimmed significantly and has stayed in this faint state ever since. We report on AstroSat and NuSTAR observation of GRS 1915+105 in its unusual low/hard state during 2019 May. We performed time-resolved spectroscopy of the X-ray flares observed in this state and found that the spectra can be fitted well using highly ionised absorption models. We further show that the spectra can also be fitted using a highly relativistic reflection dominated model, where for the lamp post geometry, the X-ray emitting source is always very close to the central black hole. For both interpretations, the flare can be attributed to a change in the intrinsic flux, rather than dramatic variation in the absorption or geometry. These reflection dominated spectra are very similar to the reflection dominated spectra reported for Active Galactic Nuclei in their low flux states.
title Time resolved spectroscopy of a GRS 1915+105 flare during its unusual low state using AstroSat
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2402.06569