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MAXI/GSC detection of a renewed activity from IGR J17191-2821

ATel #4170; J. Sugimoto (RIKEN), H. Negoro (Nihon U.), M. Serino, T. Mihara, M. Sugizaki, T. Yamamoto, M. Matsuoka (RIKEN), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa (JAXA), N. Kawai, M. Morii, R. Usui, K. Ishikawa (Tokyo Tech), A. Yoshida (AGU), H. Tsunemi, M. Kimura (Osaka U.), M. Nakajima, M. Asada, H. Sakakibara, N. Serita (Nihon U.), Y. Ueda, K. Hiroi, M. Shidatsu, R. Sato (Kyoto U.), Y. Tsuboi, M. Higa (Chuo U.) M. Yamauchi, Y. Nishimura, T. Hanayama, K. Yoshidome (Miyazaki U.), K. Yamaoka (Waseda U.) report on behalf of the MAXI team
on 13 Jun 2012; 05:25 UT
Credential Certification: Tatehiro Mihara (mihara@crab.riken.jp)

Subjects: X-ray, Binary, Neutron Star, Transient

At 2012/06/12 17:17:52 UT, the MAXI/GSC nova alert system triggered on enhanced X-ray emission from the position (259.66,-28.30) with a statistical uncertainty of 10 arcmin at the 90% confidence limit and an additional systematic uncertainty of 0.1 deg (90% containment radius). The position is consistent with IGR J17191-2821.

The one-day average X-ray flux from 2012/06/11 18:00 to 6/12 18:00 UT is about 43 +- 17 mCrab in 4-10 keV band. The source had been in invisible area for MAXI/GSC near the ISS rotation pole during June 6 - 10, 2012. The MAXI/GSC, however, detected the beginning of the outburst at June 4 00:00 (UT). The brightening of the source can also be seen in the Swift/BAT light curve ( http://heasarc.gsfc.nasa.gov/docs/swift/results/transients/weak/IGRJ17191-2821/ ).

IGR J17191-2821 was discovered with INTEGRAL in March 2007 (ATel #1021, #1022, #1025, #1065, #1068, #1070, #1075, #1096). No outburst was reported since then. The source was found to be a neutron star system showing a kH-QPO (ATel #1075) and an X-ray burst (ATel #1065).

The latest light curves and images of IGR J17191-2821 by MAXI/GSC are placed at the following URL: