Broad-Band Spectrum of The Black Hole Candidate IGR J17497-2821 Studied with Suzaku

TL;DR

This study presents a detailed broad-band X-ray spectrum of the black hole candidate IGR J17497-2821 using Suzaku, revealing key spectral features and constraining physical models of accretion in the low-hard state.

Contribution

First broad-band 1-300 keV Suzaku spectrum of IGR J17497-2821 with high signal-to-noise, analyzing spectral components and physical implications for black hole accretion.

Findings

Detection of a cut-off energy at about 150 keV

Spectral fit with multi-color disc and thermal Comptonization components

Constraints on accretion disc properties and reflection features

Abstract

The broad-band 1-300 keV Suzaku spectrum of IGR J17497-2821, the X-ray transient discovered by INTEGRAL in September 2006, is presented. Suzaku observed IGR J17497-2821 on September 25, eight days after its discovery, for a net exposure of about 53 ksec. During the Suzaku observation, IGR J17497-2821 is very bright, 2 x 10^37 erg/s at 8 kpc in the 1-300 keV range, and shows a hard spectrum, typical of black hole candidates in the low-hard state. Despite the multi-mission X-ray monitoring of the source, only with Suzaku is it possible to obtain a broad-band spectrum in the 1-300 keV range with a very high signal to noise ratio. A sum of a multi-color disc (DISKBB) and a thermal Comptonization component (COMPPS) with mild reflection is a good representation of our IGR J17497-2821 Suzaku spectrum. The spectral properties of the accretion disc as well as the cut-off energy in the spectrum at about 150 keV are clearly detected and constrained. We discuss the implications on the physical model used to interpret the data and the comparison with previous results.