Spectral and Timing Properties of the Black Hole X-Ray Binary H1743-322 in the Low/Hard State Studied with Suzaku

Shidatsu, M.; Ueda, Y.; Yamada, S.; Done, C.; Hori, T.; Yamaoka, K.; Kubota, A.; Nagayama, T.; Moritani, Y.

Abstract

We report on the results from Suzaku observations of the Galactic black hole X-ray binary H1743–322 in the low/hard state during its outburst in 2012 October. We appropriately take into account the effects of dust scattering to accurately analyze the X-ray spectra. The time-averaged spectra in the 1-200 keV band are dominated by a hard power-law component of a photon index of ≈1.6 with a high-energy cutoff at ≈60 keV, which is well described with the Comptonization of the disk emission by the hot corona. We estimate the inner disk radius from the multi-color disk component, and find that it is 1.3-2.3 times larger than the radius in the high/soft state. This suggests that the standard disk was not extended to the innermost stable circular orbit. A reflection component from the disk is detected with R = Ω/2π ≈ 0.6 (Ω is the solid angle). We also successfully estimate the stable disk component independent of the time-averaged spectral modeling by analyzing short-term spectral variability on a ~1 s timescale. A weak low-frequency quasi-periodic oscillation at 0.1-0.2 Hz is detected, whose frequency is found to correlate with the X-ray luminosity and photon index. This result may be explained by the evolution of the disk truncation radius.

Citation

Shidatsu, M., Ueda, Y., Yamada, S., Done, C., Hori, T., Yamaoka, K., …Moritani, Y. (2014). Spectral and Timing Properties of the Black Hole X-Ray Binary H1743-322 in the Low/Hard State Studied with Suzaku. Astrophysical Journal, 789(2), Article 100. https://doi.org/10.1088/0004-637x/789/2/100

• Journal Article Type: Article
• Publication Date: Jul 10, 2014
• Deposit Date: Mar 16, 2016
• Publicly Available Date: Jun 22, 2016
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 789
• Issue: 2
• Article Number: 100
• DOI: https://doi.org/10.1088/0004-637x/789/2/100
• Public URL: https://durham-repository.worktribe.com/output/1388959