RXTE observations and state transition in MAXI J1836-194

TL;DR

This paper analyzes RXTE observations of MAXI J1836-194 during its 2011 outburst, revealing state transitions, QPOs, and spectral evolution, contributing to understanding black hole transient behaviors.

Contribution

It provides detailed temporal and spectral analysis of MAXI J1836-194's outburst, highlighting a unique transition to HIMS without reaching a soft state.

Findings

Source exhibits state transition to HIMS and back to Low/Hard state.

QPOs are detected during the HIMS.

Correlation between break frequency and spectral properties observed.

Abstract

We present the results of analysis of the X-ray transient source MAXI J1836-194 during its outburst in August 2011. MAXI GSC detected the source on 30th August 2011, when it started rising from the quiescence. We have studied the source using the observations of RXTE. In this paper, we study the temporal and spectral evolution of the source during the outburst. Spectral analysis shows that the source exhibits state transition to Hard Intermediate state(HIMS) and decays back to a Low/Hard state. The temporal analysis indicates the presence of QPOs during the hard intermediate state. We also observe correlation between the evolution of break frequency with respect to the spectral characteristics. We conclude that this is probably the second source after H 1743-322 which exhibits transition to HIMS but does not reach soft spectral state.