//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18102 SUBJECT: GRB 150801A: MAXI/GSC detection DATE: 15/08/01 13:23:23 GMT FROM: H. Negoro at Nihon U. M. Ishikawa, S. Nakahira (JAXA), H. Negoro, (Nihon U.), S. Ueno, H. Tomida, M. Kimura, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, Y. Tachibana, T. Yoshii (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, T. Masumitsu, 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 01:18:55 UT. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (256.013 deg, -9.523 deg) = (17 04 03, -09 31 22) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.26 deg and 0.25 deg, respectively. The roll angle of long axis from the north direction is 50.0 deg counterclockwise. There is an 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) = (255.708 deg, -10.291 deg) = (17 02 49, -10 17 28) (J2000) (R.A., Dec) = (255.273 deg, -9.991 deg) = (17 01 05, -09 59 28) (J2000) (R.A., Dec) = (256.932 deg, -8.065 deg) = (17 07 43, -08 03 53) (J2000) (R.A., Dec) = (257.356 deg, -8.376 deg) = (17 09 25, -08 22 32) (J2000) The X-ray flux averaged over the scan was 103 +- 21 mCrab (4-10keV, 1 sigma error). There was no significant excess flux in the previous transit at 23:46 UT on 31 July and in the next transit at 02:51 UT with an upper limit of 20 mCrab for each. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18103 SUBJECT: GRB 150801A: Tiled Swift observations DATE: 15/08/01 15:37:17 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the MAXI GRB 150801A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00047 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the MAXI event is high: any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18112 SUBJECT: GRB 150801A: Swift-XRT observations DATE: 15/08/03 17:53:41 GMT FROM: Boris Sbarufatti at INAF-OAB/IASFPA A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), A.P. Beardmore (U. Leicester), B.P. Gompertz (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 150801A (Ishikawa et al. GCN Circ. 18102) in a series of observations tiled on the sky. The total exposure time is 3.8 ks, distributed over 4 tiles; the maximum exposure at a single sky location was 1.6 ks. The data were collected between T0+50.8 ks and T0+62.9 ks, and are entirely in Photon Counting (PC) mode. No X-ray sources have been detected. The 3-sigma upper limit in the field (not including the regions where the tiles overlap) ranges from ~0.006 to ~0.009 ct s^-1, corresponding to a 0.3-10 keV observed flux of 2.4e-13 to 3.8e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at http://www.swift.ac.uk/xrt_products/TILED_GRB00047. This circular is an official product of the Swift-XRT team.