Gamma-ray Burst 190404A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Notice
  

  TITLE:           GCN/MAXI NOTICE
  NOTICE_DATE:     Thu 04 Apr 19 13:23:26 UT
  NOTICE_TYPE:     MAXI Unknown Source Position 
  EVENT_ID_NUM:    577438870
  EVENT_RA:         12.09d {+00h 48m 21s} (J2000),
                    12.35d {+00h 49m 23s} (current),
                    11.42d {+00h 45m 40s} (1950)
  EVENT_DEC:       +27.49d {+27d 29' 10"} (J2000),
                   +27.59d {+27d 35' 27"} (current),
                   +27.21d {+27d 12' 48"} (1950)
  EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
  EVENT_FLUX:      399.0 +- 0.0 [mCrab] 
  EVENT_DATE:      18577 TJD;    94 DOY;   19/04/04
  EVENT_TIME:      44663.00 SOD {12:24:23.00} UT
  EVENT_TSCALE:    30s
  EVENT_EBAND:     Low, 2-4 keV  
  SUN_POSTN:        13.34d {+00h 53m 22s}   +5.71d {+05d 42' 41"}
  SUN_DIST:         21.90 [deg]  
  MOON_POSTN:        6.77d {+00h 27m 04s}   -2.21d {-02d 12' 50"}
  MOON_DIST:        30.28 [deg]  
  MOON_ILLUM:      1 [%]
  GAL_COORDS:      122.09,-35.38 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:       22.20, 20.46 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.
  

• GCN Circular #24048
  M. Nakajima, H. Negoro (Nihon U.), W. Iwakiri (Chuo U.), W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), S. Nakahira, T. Mihara, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, T. Hashimoto, A. Yoshida (AGU), Y. Tsuboi, R. Sasaki, H. Kawai, T. Sato (Chuo U.), N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita, M. Oeda, K. Shiraishi (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, S. Ogawa (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime 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 12:24:20 UT on 2019 April 4. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (12.088 deg, 27.486 deg) = (00 48 21, +27 29 09) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.13 deg and 0.12 deg, respectively. The roll angle of the long axis from the north direction is 136.0 deg counterclockwise.
  Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners:

  (12.621, 28.061) deg = (00 50 29, +28 03 39) (J2000)
  (12.378, 28.204) deg = (00 49 30, +28 12 14) (J2000)
  (11.610, 27.173) deg = (00 46 26, +27 10 22) (J2000)
  (11.851, 27.032) deg = (00 47 24, +27 01 55) (J2000)
  

  There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
  The X-ray flux averaged over the scan was 399 +- 41 mCrab (4.0-10.0keV, 1 sigma error). There was no significant excess flux in the previous transit at 10:51 UT on 2019 April 4 with an upper limit of 20 mCrab.
  Note that we noticed that Fermi had detected a GRB at 07:01 on April 4. Then, we rename this burst, referred to as GRB 190304A in the MAXI new-transient ML, GRB 190404B. We apologize for a series of mistakes.
• GCN Circular #24050
  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 190404B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00079
  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 #24055
  S. Nakahira (RIKEN), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena), and the CALET collaboration:
  The long GRB 190404B (MAXI/GSC detection: Nakajima et al., GCN Circ. 24048) was detected in ground analysis of the CALET Gamma-ray Burst Monitor (CGBM) data near the MAXI trigger time at T0=12:24:20 UTC on 4 April 2019. The burst signal was seen by all CGBM detectors.
  The burst light curve shows a single multi-peaked emission episode which starts at T-15.1 sec and ends at T+80.4 sec. The T90 and the T50 durations measured by the SGM data are 87.5 +- 18.8 sec and 47.6 +- 17.5 sec (40-1000 keV), respectively.
  The ground processed light curve is available at
  http://cgbm.calet.jp/cgbm_trigger/ground/1238415870/
  The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
• GCN Circular #24083
  A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline on behalf of the Konus-Wind team, report:
  The long GRB 190404B which triggered MAXI/GSC at 12:24:20 UT (MAXI/GSC detection: Nakajima et al., GCN 24048; CALET Gamma-Ray Burst Monitor detection: Nakahira et al., GCN 24055) was detected by Konus-Wind in the waiting mode.
  The burst light curve shows a single multi-peaked emission episode started at ~T0(MAXI)-7.4 s with a total� duration of ~85.4 s.
  As observed by Konus-Wind, the burst had a fluence of 5.57(-1.00,+1.34)x10^-6 erg/cm2 and a 2.944-s peak flux, measured from ~T0(MAXI)+51.5 s, of 1.09(-0.20,+0.26)x10^-7 erg/cm2/s (both in the 20 - 1200 keV energy range).
  Fitting the K-W 3-channel time-integrated spectrum (from ~T0(MAXI)-7.4 s to ~T0(MAXI)+78.0 s) in the 20 keV - 1.2 MeV range by a power law with exponential cutoff model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.64(-0.36,+3.80), and Ep =80(-39,+33) keV.
  All the quoted errors are estimated at the 1 sigma confidence level. All the presented results are preliminary.
  The K-W light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB190404B/
• GCN Circular #24120
  H. Negoro (Nihon U.) report on behalf of the MAXI team:
  The GRB names of 140404B/190404B (Nakajima et al. GCN Circ. 24048) and 140404C/190404C (Yamada et al. GCN Circ. 24049) should be 190404A and 190404B, respectively. I sincerely apologize for the late correction and for any confusion caused.