MAXI/GSC detection of renewed activity of the black hole candidate V4641 Sgr
ATel #7858; T. Yoshii (Tokyo Tech), H. Negoro, (Nihon U.), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, T. Masumitsu, K. Tanaka (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, S. Kanetou (Chuo U.), M. Yamauchi, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Morii (ISM) report on behalf of the MAXI team:
on 30 Jul 2015; 15:04 UT
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)
Subjects: X-ray, Binary, Black Hole, Transient
We report on an enhancement of X-ray flux from the black hole candidate V4641 Sgr detected with MAXI/GSC. The MAXI/GSC nova alert system triggered the event at 19:16 on 2015 July 29 (UT) (MJD 57232) (for the trigger event, see http://maxi.riken.jp/pipermail/x-ray-star/2015-July/000387.html ). MAXI daily light curves of this source show that this new outburst has started around 2015 July 20, and the 2-4 keV and 4-10 keV fluxes have gradually increased, reaching 17.3 +/- 8.8 and 26.9 +/- 8.2 mCrab on MJD57232.0-57233.0, respectively.
The long-term 2-10 keV light curve of MAXI/GSC shows at least three outbursts with peak fluxes of beyond about 5 mCrab around MJD 55420 (ATel #2785, #2832, #2892) ,MJD 56090 and MJD 56660 (ATel #5803, #5836), and the interval is about 600 days.
The latest light curves and image of this source are available at the following URL: http://maxi.riken.jp/top/index.php?cid=1&jname=J1819-254. Multi-wavelength observations are encouraged.
