TITLE: GCN CIRCULAR NUMBER: 18596 SUBJECT: GRB 151112A: MAXI/GSC detection DATE: 15/11/13 01:34:09 GMT FROM: Satoshi Nakahira at JAXA/MAXI K. Yamaoka (Nagoya U.), H. Negoro, T. Masumitsu (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, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, 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: The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 13:45:24 UT. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (1.543 deg, -61.934 deg) = (00 06 10, -61 56 03) (J2000) with a 90% C.L. statistical error of 0.25 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). This position is consistent with Swift GRB 151112A (Malesani et al., GCN Circ. 18588). The X-ray flux averaged over the scan was 217 +- 31 mCrab (4-10keV, 1 sigma error). There was no significant excess flux in the previous transit at 12:12 UT and in the next transit at 2015-11-12 15:17 UT with an upper limit of 20 mCrab for each.