MAXI/GSC detection of the tail of a long thermonuclear X-ray burst from 4U 1850-08
ATel #5978; M. Serino, M. Matsuoka (RIKEN), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa (RIKEN), N. Kawai, R. Usui, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Nakano, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, M. Sasaki, D. Uchida (Osaka U.), H. Negoro, M. Nakajima, H. Sakakibara, K. Fukushima, T. Onodera, K. Suzuki (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, M. Higa (Chuo U.), M. Yamauchi, K. Yoshidome, Y. Ogawa, H. Yamada, Y. Morooka (Miyazaki U.), K. Yamaoka (Nagoya U.) on behalf of the MAXI team
on 14 Mar 2014; 13:11 UT
Credential Certification: Motoko Suzuki (motoko@crab.riken.jp)
MAXI/GSC observed the position of 4U 1850-08 about 74 min after the
Swift BAT trigger (in 't Zand et al. ATel #5972).
The epoch of the transit center was 22:18:54 on March 10, 2014 (UT),
and the duration of the transit was 62 s.
The flux at that time was 75 +- 22 mCrab (4-10 keV, 1 sigma error)
and the blackbody temperature estimated from the 4-10 keV to 2-4 keV
hardness ratio was 1.4 +- 0.4 keV.
This flux level is consistent with the e-folding time of 103 s
estimated by in 't Zand et al..
The central epochs of the next two transits were
23:55 and 1:24 (on March 11). The flux averaged over these two
transits was 22 +- 9 mCrab (4-10 keV, 1 sigma error).
It suggests that the duration of the X-ray burst is longer than
4.3 hours, although the emission is not separable from the persistent
emission.
A similar long burst from this source was reported in Cominsky et al.
(1977, ApJ 211, L9), which might have lasted ~ 78 min.