MAXI detection of a super-burst from EXO 1745-248 in Terzan 5
ATel #3729; T. Mihara, M. Matsuoka, M. Sugizaki, M. Serino, S. Nakahira, T. Yamamoto, T. Sootome (RIKEN),S. Ueno, H. Tomida, M. Kohama, M. Ishikawa (JAXA),N. Kawai, M. Morii, K. Sugimori, R. Usui, T. Toizumi (Tokyo Tech),A. Yoshida, K. Yamaoka (AGU),H. Tsunemi, M. Kimura, H. Kitayama (Osaka U.), H. Negoro, M. Nakajima, F. Suwa (Nihon U.), Y. Ueda, K. Hiroi, M. Shidatsu (Kyoto U.), Y. Tsuboi, T. Matsumura, K. Yamazaki (Chuo U.)report on behalf of the MAXI team
on 1 Nov 2011; 10:03 UT
Credential Certification: Tatehiro Mihara (mihara@crab.riken.jp)
Subjects: X-ray, Binary, Globular Cluster, Neutron Star, Transient
Referred to by ATel #: 3743
MAXI detected the initial burst component from EXO 1745-248 in Terzan 5 (ATel #3714, #3718, #3720).
The light curve obtained by MAXI shows an exponential decay with an e-folding time of 10 hour.
If the emission is originated by the blackbody radiation, the temperature can be estimated from the
hardness of the two energy bands.
MJD 4-10/2-4 keV kT [keV] 10-20/4-10 keV kT [keV]
55858.53 2.9 2.9 ± 0.8 0.32 2.4 ± 0.6
55858.59 1.5 1.7 ± 0.4 0.19 2.0 ± 0.8
55858.78 1.05 1.4 ± 0.4 0.50 2.8 ± 1.0
55858.84 1.24 1.58 ± 0.5 0.37 1.85 ± 0.8
55858.91 1.06 1.43 ± 0.5 0.19 1.83 ± 1.5
55858.97 1.03 1.40 ± 0.5 0.06 1.80 ± 3.9
(Errors are 1-sigma.)
The temperatures estimated from 4-10/2-4 keV and 10-20/4-10 keV
are consistent with each other.
It showed a softening from 2.9 keV in the beginning to 1.5 keV in the end.
The fluence is 2.4 × 10
42 erg in 2-10 keV assuming 8.7 kpc distance (Cohn et al. ApJ 571 818 (2002)).
The sphere radius of the blackbody is 6.3 km with using 2 keV and 6.8 × 10
37 erg/s at the peak.
Those (e-folding time, temperature, softening, fluence, and radius) are
typical as a super-burst from low-mass X-ray binaries.
The light curve and temperature plot are available at
http://maxi.riken.jp/top/index.php?cid=34
and
http://maxi.riken.jp/top/index.php?cid=1&jname=J1748-248
