Spectro-temporal evolution during the onset-phase of the 2011 outburst of IGR J17091-3624. Implications on accretion disk dynamics

TL;DR

This study analyzes the spectral and temporal evolution during the 2011 outburst of IGR J17091-3624, revealing state transitions and accretion disk dynamics through archival data from multiple satellites.

Contribution

It provides a detailed re-analysis of multi-satellite data to understand state transitions and accretion flow behavior during the outburst onset.

Findings

Identification of clear state transitions from hard to soft states

Insights into the evolution of X-ray features during outburst

Implications for accretion disk dynamics and flow types

Abstract

We re-analysed the archival data of RXTE / INTEGRAL / Swift satellites at the onset phase of the 2011 outburst of the X-ray source IGR J17091-3624. The evolution of the spectral and temporal properties of the source in this phase clearly exhibits state transition as Hard (HS) to Hard-Intermediate (HIMS) to Soft-Intermediate (SIMS) to Soft (SS) state, before entering the variability phase (VP).We attempt to understand the evolution of X-ray features and the state transitions based on two different types of accreting material (i.e, the Keplerian and sub-Keplerian flow).