//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23937 SUBJECT: GRB 190306A: MAXI/GSC detection DATE: 19/03/07 02:09:26 GMT FROM: H. Negoro at Nihon U. M. Shidatsu (Ehime U.), H. Negoro (Nihon U.), M. Serino (AGU), M. Nakajima, A. Sakamaki, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), T. Mihara, S. Nakahira, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, T. Hashimoto, A. Yoshida (AGU), N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai, T. Midooka (JAXA), Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, S. Ogawa (Kyoto U.), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, K. Hidaka, S. Iwahori (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray transient source at 2019 March 06 UT 20:51:59. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (222.563 deg, 30.944 deg) = (14 50 15, +30 56 38) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.34 deg and 0.33 deg, respectively. The roll angle of long axis from the north direction is 142.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 81 +- 16 mCrab (4.0-10.0keV, 1 sigma error). There was no significant excess flux in the previous transit at UT 19:19 and in the next transit at UT 22:24 with an upper limit of 20 mCrab for each. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23938 SUBJECT: GRB 190306A: Tiled Swift observations DATE: 19/03/07 03:43:22 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 190306A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00078 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: 23941 SUBJECT: GRB 190306A: Swift-XRT observations DATE: 19/03/07 17:38:55 GMT FROM: Valerio D'Elia at ASDC D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA) 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 190306A (Shidatsu et al. GCN Circ. 23937) in a series of observations tiled on the sky. The total exposure time is 1.2 ks, distributed over 7 tiles; the maximum exposure at a single sky location was 379 s. The data were collected between T0+24.2 ks and T0+25.6 ks, and are entirely in Photon Counting (PC) mode. No uncatalogued X-ray sources have been detected. The 3-sigma upper limit in the field (not including the regions where the tiles overlap) ranges from ~0.05 to ~0.15 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.8e-12 to 6.1e-12 erg cm^-2 s^-1 (assuming a typical GRB spectrum). A previously-catalogued X-ray source has been detected, however because it is a catalogued object it is unlikely to be the afterglow. 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_GRB00078. This circular is an official product of the Swift-XRT team.