TITLE: GCN CIRCULAR NUMBER: 17077 SUBJECT: GRB 141121A: MAXI/GSC detection DATE: 14/11/21 06:31:44 GMT FROM: H. Negoro at Nihon U. F. Honda, K. Fukushima, H. Negoro (Nihon U.), N. Kawai (Tokyo Tech), S. Nakahira (JAXA), M. Serino (RIKEN), S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), Y. Tachibana, T. Yoshii (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, D. Uchida (Osaka U.), M. Nakajima, T. Onodera, K. Suzuki, T. Namba, M. Fujita (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.) We report the MAXI/GSC detection of GRB 141121A (Li et al. GCN 17075). The MAXI/GSC detected the source in the scan transit at 2014-11-21T03:44:47 (UT), earlier than about 6 min before the BAT trigger. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (122.928 deg, 22.053 deg) = (08 11 42, +22 03 10) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.44 deg and 0.4 deg respectively. The roll angle of long axis from the north direction is 174.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). This position is consistent with that reported as GRB 141121A. The X-ray flux averaged over the scan was 57 +- 17 mCrab (4-10keV, 1 sigma error). There was no significant excess flux in the previous transit at UT 00:39. and in the next transit at 05:17 UT with an upper limit of 20 mCrab for each. A simple power-law fit to the GSC spectrum gives a power-law index of 2.3 +/- 1.0. These nature implies that the source is a long-GRB, or a new X-ray transient. The followup observations are strongly encouraged to reveal the nature of the source.