MAXI/GSC detection of a soft X-ray transient MAXI J1135-606
ATel #8322; H. Negoro (Nihon U.), S. Nakahira, S. Ueno, H. Tomida, 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, M. Arimoto, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori, A. Tanimoto (Kyoto U.), M. Yamauchi, D. Itoh (Miyazaki U.), Y. Tsuboi, S. Kanetou, Y. Nakamura, R. Sasaki (Chuo U.), K. Yamaoka (Nagoya U.), M. Morii (ISM)
on 23 Nov 2015; 06:33 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)
Subjects: X-ray, Transient
The MAXI/GSC detected a soft X-ray transient near a bright X-ray pulsar Cen X-3 on 2015 November 22. Preliminary analysis shows the source position at (R.A., Dec) = (173.76 deg, -60.6 deg) with an error of 0.3 deg or more. A large amount of contamination of X-rays from Cen X-3 and the soft energy spectrum of the new source make it difficult to obtain the source position statistically. A more precise position may be given through the MAXI mailing list.
The source has a very soft X-ray energy spectrum characterized by the blackbody temperature of 0.67 +- 0.09 keV, and no interstellar absorption is necessary for the blackbody fit.
The source flux has been detected since the scan transit at 09:29 UT on 2015 November 22, and tends to decrease. The 2-4 keV and 4-10 keV photon fluxes were 0.27 +/- 0.09 c/cm^2/s and 0.02 +/- 0.04 c/cm^2/s at 09:29, 0.20 +/- 0.05 c/cm^2/s and 0.03 +/- 0.02 c/cm^2/s averaged over 3 scan transits from 18:44 to 23:22 on November 22, and 0.13 +/- 0.04 c/cm^2/s and 0.02 +/- 0.02 c/cm^2/s averaged over 3 scan transits from 00:55 on November 23 to 04:00, respectively. The average 2-10 keV flux in the above 7 scan transits was (1.04 +- 0.20)x 10^-9 erg/cm^2/s.
Since there are no known bright X-ray sources near the source position, we tentatively name the source MAXI J1135-606 (the same as J1130-608 in the MAXI mailing list "New-transient:189, X-ray-star:189", we apologize for the confusion). We encourage followup observations.
