Record Details

Spectral Class Transition of GRO J1655-40 during 2005 outburst in the Light of TCAF Model

NOPR - NISCAIR Online Periodicals Repository

View Archive Info
 
 
Field Value
 
Title Spectral Class Transition of GRO J1655-40 during 2005 outburst in the Light of TCAF Model
 
Creator Bari, Md Washimul
Chatterjee, Achintya Kumar
 
Subject X-Rays
Binaries–stars individual
(GRO J1655-40)–stars
Black holes–accretion
Accretion disks – spectrum – radiation
Dynamics
 
Description 689-699
Galactic transient black hole candidates often show notable changes in their X-ray properties during outbursts. In this
paper we study the timing and spectral properties of the transient X-ray binary GRO J1655-40 during its 2005 outburst using
the Two Component Advective Flow (TCAF) model as a local model in XSPEC. We analyze the data of PCA onboard the
Rossi X-ray Timing Explorer (RXTE) satellite from February to October 2005. Here we present a detailed insight in to the
mass accretion mechanism and the characteristics of the accretion disk around the black hole candidate throughout the
period of outburst. Based on the TCAF model fitting, parameters of the accretion flow e.g., the Keplerian rate or disk rate,
sub-Keplerian rate or halo rate, shock location and the compression ratio or the shock strength are derived. On the basis of
the evolution of the accretion rate ratio (ARR) or the ratio of the halo rate to the disk rate and considering the presence or
absence of the Quasi-Periodic Oscillations (QPOs), we have categorized the entire outburst into four distinct spectral states:
hard, hard-intermediate, soft-intermediate, and soft. It reveals that these distinct spectral states form a characteristic q-like
pattern or hysteresis loop following the sequence: hard – hard-intermediate – soft-intermediate – soft – soft-intermediate –
hard-intermediate – hard. We find that during the rising or declining phases, where the QPO frequencies are increasing or
decreasing respectively, there is an associated rise in the value of the halo rate compared to the disk rate. We have also
observed that the ARR reaches its maximum on the day of transition from the hard state to the hard-intermediate state during
the rising phase, and on the day of transition from the hard-intermediate state to the hard state during the declining phase.
 
Date 2024-08-05T10:16:37Z
2024-08-05T10:16:37Z
2024-08
 
Type Article
 
Identifier 0975-0959 (Online); 0301-1208 (Print)
http://nopr.niscpr.res.in/handle/123456789/64324
https://doi.org/10.56042/ijpap.v62i8.8432
 
Language en
 
Publisher NIScPR-CSIR,India
 
Source IJPAP Vol.62(08) [August 2024]