//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12901 SUBJECT: GRB 120127A: MAXI/GSC detection of a probable GRB DATE: 12/01/27 11:53:36 GMT FROM: Mikio Morii at Tokyo Inst Tech S. Song, M. Morii (Tokyo Tech), H. Negoro, F. Suwa (Nihon U.), M. Serino, S. Nakahira (RIKEN), S. Ueno, H. Tomida, M. Kohama, M. Ishikawa (JAXA), T. Mihara, M. Sugizaki, T. Yamamoto, T. Sootome, M. Matsuoka (RIKEN), N. Kawai, K. Sugimori, R. Usui, T. Toizumi, Y. Aoki (Tokyo Tech), A. Yoshida, K. Yamaoka (AGU), H. Tsunemi, M. Kimura, H. Kitayama (Osaka U.), M. Nakajima, M. Asada, H. Sakakibara (Nihon U.), Y. Ueda, K. Hiroi, M. Shidatsu (Kyoto U.), Y. Tsuboi, T. Matsumura, K. Yamazaki (Chuo U.) M. Yamauchi, Y. Nishimura, T. Hanayama (Miyazaki U.) report on behalf of the MAXI team: MAXI/GSC triggered at 2012-01-27 04:21:52 UT on an uncatalogued X-ray transient source. The transient emission lasted for about 10 seconds within the 50 second long triangular transit response of MAXI/GSC. We identify this event as GRB 120127A. Assuming that the source flux was constant over the transit, we obtain a statistical 90% C.L. elliptical error region centered on (R.A., Dec) = (139.14 deg, 15.88 deg) = (09 16 34, +15 52 51)(J2000) with long and short radii of 0.74 deg and 0.52 deg, respectively. The position angle of long axis is 53.7 deg. There is additional systematic uncertainty of 0.1 deg (90% containment radius). Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners: (R.A., Dec) = (138.12 deg, 15.61 deg) = (09 12 29, +15 36 32)(J2000) (R.A., Dec) = (138.95 deg, 14.87 deg) = (09 15 47, +14 52 29)(J2000) (R.A., Dec) = (140.82 deg, 16.80 deg) = (09 23 16, +16 48 02)(J2000) (R.A., Dec) = (140.00 deg, 17.54 deg) = (09 20 01, +17 32 09)(J2000) The X-ray flux averaged over the scan was 48 +- 21 mCrab (4-10 keV, 1 sigma error). Follow-up observations are encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12902 SUBJECT: GRB 120127A: MASTER optical observations DATE: 12/01/27 15:38:06 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, V.V.Chazov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Sankovich, S. Shurpakov Moscow State University, Sternberg Astronomical Institute O.Gres, O.Chuvalaev,K.Ivanov, V.A.Poleshchuk, S.Yazev, N.M.Budnev Irkutsk State University V.Krushinski, I.Zalozhnich, A. Popov Ural State University, Kourovka E. Sinykov, V.Yurkov, Yu.Sergienko, D.Varda, Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory MASTER II robotic double telescope (FOW=2x4 square degrees, http://observ.pereplet.ru) located in Tunka was pointed to the GRB120127A (MAXI/GSC, Song et al., GCN Circ 12901) 9h 30 min after GRB time at 2012-01-27 04:21:52 UT in two polarizations. On our images we haven`t found optical transient within error-box (Song et al., GCN Circ 12901). The delay is due to the MAXI/GSC ground reduction. Date UT UT Exp Coadd Limit Start Mean Time 2012-01-27 13:51:59 13:53:29 180s no 18.9 2012-01-27 13:51:59 13:58:40 900s yes 19.9 This circular was generated automatically. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12903 SUBJECT: GRB 120127A / P48 Imaging DATE: 12/01/28 23:41:44 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (UC Berkeley), E. O. Ofek (Weizmann Institute), and P. E. Nugent (LBNL/UC Berkeley) report on behalf of a larger collaboration: We have imaged the location of the MAXI GRB120127A (Song et al., GCN 12901) with the Palomar 48 inch Oschin Schmidt telescope as part of the Palomar Transient Factory. Observations began at 3:41 UT on 28 January 2012 (~ 23.3 hours after the MAXI trigger) and cover ~ 90% of the MAXI error localization. By comparing sources detected in our images with the USNO-B1 catalog, 2MASS point source catalog, and the Digital Palomar Optical Sky Survey archival images, we find no new sources within the MAXI error localization (aside from a number of known minor planets). The limiting magnitude of our imaging is R >~ 19.5 mag (calculated with respect to field stars from the USNO-B catalog).