[ Previous | Next | ADS ]

Swift XRT observation of the black hole candidate H 1743-322

ATel #2781; K. Yamaoka, S. Nakahira, A. Yoshida (Aoyama Gakuin Univ.), H. Negoro, M. Nakajima, H. Ozawa, F. Suwa (Nihon U.), T. Mihara, M. Sugizaki, M. Suzuki, Y. E. Nakagawa, T. Yamamoto, T. Sootome, M. Matsuoka (RIKEN), N. Kawai, M. Morii, K. Sugimori, R. Usui (Tokyo Tech), K. Kawasaki, S. Ueno, H. Tomida, M. Kohama, M. Ishikawa (JAXA), H. Tsunemi, M. Kimura (Osaka U.), Y. Ueda, N. Isobe, S. Eguchi, K. Hiroi (Kyoto U.), A. Daikyuji (Miyazaki U.), A. Uzawa, T. Matsumura, K. Yamazaki (Chuo U.), on behalf of the MAXI team
on 8 Aug 2010; 14:39 UT
Credential Certification: Kazutaka Yamaoka (yamaoka@phys.aoyama.ac.jp)

Subjects: X-ray, Binary, Black Hole, Transient

Referred to by ATel #: 2788, 3263

Following the MAXI/GSC, RXTE/PCA and Swift/BAT detection of a re-brightening of the black hole candidate H 1743-322 (ATel #2774), we carried out a Swift ToO observation on 7 August 2010 with a net exposure of 1.2 ksec. The Swift XRT was operated in the windowed timing mode. The XRT spectrum can be fitted with a power law of 1.65+/-0.08 modified with the Galactic absorption of N_H = (2.05+/-0.13)x10^22 cm^-2 (chi^2/d.o.f. = 416.9/363). The absorbed flux was 6.8x10^-10 erg/cm^2/s in the 2-10 keV range, corresponding to about 31 mCrab. This result confirms that the source is currently in the initial low/hard state, and is probably moving to the state transition. Further Swift XRT observations are planned.