Gamma-ray Burst 190828A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN NOTICE
  

  TITLE:           GCN/MAXI NOTICE
  NOTICE_DATE:     Wed 28 Aug 19 08:09:04 UT
  NOTICE_TYPE:     MAXI Unknown Source Position
  EVENT_ID_NUM:    723277116
  EVENT_RA:         58.07d {+03h 52m 17s} (J2000),
                    58.42d {+03h 53m 41s} (current),
                    57.18d {+03h 48m 43s} (1950)
  EVENT_DEC:       +46.55d {+46d 33' 04"} (J2000),
                   +46.61d {+46d 36' 31"} (current),
                   +46.40d {+46d 24' 07"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      521.0 +- 0.0 [mCrab]
  EVENT_DATE:      18723 TJD;   240 DOY;   19/08/28
  EVENT_TIME:      28688.00 SOD {07:58:08.00} UT
  EVENT_TSCALE:    30s
  EVENT_EBAND:     Low, 2-4 keV
  SUN_POSTN:       156.60d {+10h 26m 25s}   +9.77d {+09d 45' 59"}
  SUN_DIST:         88.46 [deg] 
  MOON_POSTN:      127.78d {+08h 31m 06s}  +20.66d {+20d 39' 52"}
  MOON_DIST:        61.12 [deg]
  MOON_ILLUM:      7 [%]
  GAL_COORDS:      152.31, -5.75 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:       66.19, 25.72 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.
  

• GCN Circular #25502
  S. Sugita, H. Nishida, M. Serino (AGU), H. Negoro (Nihon U.), K. Asakura (Osaka U.), M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, A. Yoshida (AGU), W. Iwakiri, Y. Tsuboi, R. Sasaki, H. Kawai, T. Sato (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, M. Sugizaki, M. Oeda, K. Shiraishi (Tokyo Tech), S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, N.Isobe, R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi, T. Yoneyama, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara, K. Kurogi, K. Miike (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 a bright uncatalogued X-ray transient source at 07:58:01 UT on 2019 August 28. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (58.011 deg, 46.448 deg) = (03 52 02, +46 26 52) (J2000) with a 90% C.L. statistical error of 0.25 deg and 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:

  (56.303, 46.041) deg = (03 45 12, +46 02 27) (J2000)
  (56.644, 45.605) deg = (03 46 34, +45 36 17) (J2000)
  (60.044, 46.816) deg = (04 00 10, +46 48 57) (J2000)
  (59.724, 47.262) deg = (03 58 53, +47 15 43) (J2000)
  

  The X-ray flux averaged over the scan was 193 +- 27 mCrab (4.0-10.0keV, 1 sigma error).
• GCN Circular #25529
  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 190828A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00086
  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 #25542
  J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), B. Sbarufatti (PSU), D.N. Burrows (PSU) 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 190828A (Sugita et al. GCN Circ. 25502) in a series of observations tiled on the sky. The total exposure time is 1.3 ks, distributed over 7 tiles; the maximum exposure at a single sky location was 393 s. The data were collected between T0+48.4 ks and T0+49.8 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 ~0.02 to ~0.15 ct s^-1, corresponding to a 0.3-10 keV observed flux of 9.9e-13 to 5.8e-12 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 https://www.swift.ac.uk/xrt_products/TILED_GRB00086.
  This circular is an official product of the Swift-XRT team.