Black hole transients

TL;DR

This paper reviews 16 years of multi-wavelength observations of black hole transients, highlighting spectral/timing states, their transitions, and the connection to jet ejections, providing a framework for future theoretical and observational studies.

Contribution

It offers a comprehensive overview of observational phenomenology and state classifications of black hole transients, integrating data across multiple wavelengths and discussing future mission prospects.

Findings

Identification of distinct spectral/timing states and their transitions.

Correlation between state changes and radio jet ejections.

Framework for understanding accretion-ejection connection.

Abstract

Sixteen years of observations of black hole transients with the Rossi X-ray Timing Explorer, complemented by other X-ray observatories and ground-based optical/infrared/radio telescopes have given us a clear view of the complex phenomenology associated with their bright outbursts. This has led to the definition of a small number of spectral/timing states which are separated by marked transitions in observables. The association of these states and their transitions to changes in the radio emission from relativistic radio jets completes the picture and have led to the study of the connection between accretion and ejection. A good number of fundamental questions are still unanswered, but the existing picture provides a good framework on which to base theoretical studies. We discuss the current observational standpoint, with emphasis onto the spectral and timing evolution during outbursts, as well as the prospects for future missions such as ASTROSAT (2012) and LOFT (>2020 if selected).