Suzaku observations of the black hole candidate IGR J1709.1-3624 in the low/hard state
Abstract
IGR J1709.1-3624 is a unique Galactic black hole candidate (BHC) that shows limit-cycle variation on a time scale of seconds to minutes besides the other peculiar BHC GRS 1915+105. It is an important object to study black hole accretion flows under very high mass accretion rates in comparison with GRS 1915+105. We observed IGR J1709.1-3624 with Suzaku twice, on October 2012 and Feburuary 2013. The observed flux in the 0.7-300 keV band was 1.4e-9 and 6.3e-10 erg/s/cm2, respectively. The XIS and HXD broad-band energy spectra in both epochs can be well explained by a thermal Comptonization model with an electron temperature of about 90-110 keV and an optical depth of about 1.3-1.6. The spectra are typical for BHCs in the low/hard state, whereas GRS 1915+105 has never experienced this state since its discovery. This suggests that IGR J1709.1-3624 had a wider range of the mass accretion rate than that of GRS 1915+105. In this paper, we present the Suzaku results together with other multiwavelength data and the comparison with other BHCs.
- Publication:
-
40th COSPAR Scientific Assembly
- Pub Date:
- 2014
- Bibcode:
- 2014cosp...40E3689Y