Gamma-ray Burst 190306A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Notice
  

  TITLE:           GCN/MAXI NOTICE
  NOTICE_DATE:     Wed 06 Mar 19 22:57:05 UT
  NOTICE_TYPE:     MAXI Unknown Source Position
  EVENT_ID_NUM:    548652539
  EVENT_RA:        223.00d {+14h 52m 01s} (J2000),
                   223.21d {+14h 52m 49s} (current),
                   222.47d {+14h 49m 54s} (1950)
  EVENT_DEC:       +30.55d {+30d 32' 42"} (J2000),
                   +30.47d {+30d 28' 01"} (current),
                   +30.75d {+30d 44' 58"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      175.0 +- 0.0 [mCrab] 
  EVENT_DATE:      18548 TJD;    65 DOY;   19/03/06
  EVENT_TIME:      75130.00 SOD {20:52:10.00} UT
  EVENT_TSCALE:    1s
  EVENT_EBAND:     Medium, 4-10 keV
  SUN_POSTN:       347.19d {+23h 08m 45s}   -5.49d {-05d 29' 27"} 
  SUN_DIST:        121.87 [deg]
  MOON_POSTN:      351.71d {+23h 26m 50s}   -8.02d {-08d 01' 01"}
  MOON_DIST:       127.02 [deg]
  MOON_ILLUM:      0 [%]
  GAL_COORDS:       47.54, 63.45 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      208.13, 44.42 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.
  

• GCN Notice
  

  TITLE:           GCN/MAXI NOTICE
  NOTICE_DATE:     Thu 07 Mar 19 00:25:51 UT
  NOTICE_TYPE:     MAXI Unknown Source Position
  EVENT_ID_NUM:    548652539     
  EVENT_RA:        222.56d {+14h 50m 15s} (J2000),
                   222.77d {+14h 51m 04s} (current),
                   222.04d {+14h 48m 08s} (1950)
  EVENT_DEC:       +30.94d {+30d 56' 38"} (J2000),
                   +30.87d {+30d 51' 55"} (current),
                   +31.15d {+31d 08' 59"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      81.0 +- 0.0 [mCrab]
  EVENT_DATE:      18548 TJD;    65 DOY;   19/03/06
  EVENT_TIME:      75130.00 SOD {20:52:10.00} UT
  EVENT_TSCALE:    1s
  EVENT_EBAND:     Medium, 4-10 keV
  SUN_POSTN:       347.24d {+23h 08m 58s}   -5.47d {-05d 28' 01"}
  SUN_DIST:        122.18 [deg]
  MOON_POSTN:      352.41d {+23h 29m 38s}   -7.76d {-07d 45' 42"}
  MOON_DIST:       127.73 [deg]  
  MOON_ILLUM:      0 [%] 
  GAL_COORDS:       48.44, 63.83 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      207.42, 44.63 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.
  

• GCN Circular #23937
  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.
• GCN Circular #23938
  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.
• GCN Circular #23941
  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.