Accretion Flow Dynamics of MAXI J1659-152 from the Spectral Evolution Study of its 2010 Outburst using the TCAF Solution

TL;DR

This study analyzes the spectral evolution of the 2010 outburst of the transient black hole candidate MAXI J1659-152 using the TCAF model, revealing detailed accretion flow dynamics and their relation to spectral states.

Contribution

It applies the TCAF spectral model to RXTE data to extract accretion flow parameters during the outburst, providing new insights into the flow dynamics and spectral state transitions.

Findings

Accretion flow parameters vary systematically during the outburst.

The source did not exhibit a soft spectral state.

TCAF parameters correlate well with traditional spectral fluxes.

Abstract

Transient black hole candidates are interesting objects to study in X-rays as these sources show rapid evolutions in their spectral and temporal properties. In this paper, we study the spectral properties of the Galactic transient X-ray binary MAXI~J1659-152 during its very first outburst after discovery with the archival data of RXTE Proportional Counter Array instruments. We make a detailed study of the evolution of accretion flow dynamics during its 2010 outburst through spectral analysis using the Chakrabarti-Titarchuk two-component advective flow (TCAF) model as an additive table model in XSPEC. Accretion flow parameters (Keplerian disk and sub-Keplerian halo rates, shock location and shock strength) are extracted from our spectral fits with TCAF. We studied variations of these fit parameters during the entire outburst as it passed through three spectral classes: hard, hard-intermediate, and soft-intermediate. We compared our TCAF fitted results with standard combined disk black body (DBB) and power-law (PL) model fitted results and found that variations of disk rate with DBB flux and halo rate with PL flux are generally similar in nature. There appears to be an absence of the soft state unlike what is seen in other similar sources.