TITLE: GCN CIRCULAR NUMBER: 17293 SUBJECT: GRB 150110C: MAXI/GSC detection DATE: 15/01/11 01:59:19 GMT FROM: H. Negoro at Nihon U. GRB 150110C: MAXI/GSC detection S. Nakahira (JAXA), H. Negoro (Nihon U.), S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), N. Kawai, Y. Tachibana, T. Yoshii (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, D. Uchida (Osaka U.), M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki, M. Fujita, F. Honda, T. Namba (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, A. Kawagoe (Chuo U.), M. Yamauchi, Y. Morooka, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered a bright uncatalogued hard X-ray transient source at UT2015-01-10T23:41:01. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (68.576 deg, -16.869 deg) = (04 34 18, -16 52 08) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.19 deg and 0.17 deg respectively. The roll angle of long axis from the north direction is 165.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 281 +- 32 mCrab (4-10keV, 1 sigma error). There was no significant excess flux in the previous transit at UT 22:08 with an upper limit of 20 mCrab.