Gamma-ray Burst 220404A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Mon 04 Apr 22 11:55:23 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     1101133,   Seg_Num: 0
  GRB_RA:           50.448d {+03h 21m 47s} (J2000),
                    50.750d {+03h 23m 00s} (current),
                    49.770d {+03h 19m 05s} (1950)
  GRB_DEC:         +10.005d {+10d 00' 16"} (J2000),
                   +10.083d {+10d 04' 59"} (current),
                    +9.826d {+09d 49' 33"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       12995 [cnts]    Image_Peak=277 [image_cnts]
  TRIGGER_DUR:     4.096 [sec] 
  TRIGGER_INDEX:   450     E_range: 15-50 keV
  BKG_INTEN:       118212 [cnts]
  BKG_TIME:        42811.09 SOD {11:53:31.09} UT
  BKG_DUR:         40 [sec]
  GRB_DATE:        19673 TJD;    94 DOY;   22/04/04
  GRB_TIME:        42870.42 SOD {11:54:30.42} UT
  GRB_PHI:         -44.79 [deg]
  GRB_THETA:        36.00 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     10.58 [sigma]
  IMAGE_SIGNIF:    7.50 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +2  +1  -2 -105  +0 -79  +0 
  SUN_POSTN:        13.54d {+00h 54m 08s}   +5.79d {+05d 47' 32"}
  SUN_DIST:         37.09 [deg]   Sun_angle= -2.5 [hr] (East of Sun)
  MOON_POSTN:       49.89d {+03h 19m 34s}  +18.39d {+18d 23' 34"}
  MOON_DIST:         8.35 [deg]
  MOON_ILLUM:      10 [%]
  GAL_COORDS:      172.58,-37.97 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:       50.69, -8.20 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Coordinates.  
  COMMENTS:        This is a rate trigger.  
  COMMENTS:        A point_source was found.  
  COMMENTS:        This does not match any source in the on-board catalog.  
  COMMENTS:        This does not match any source in the ground catalog.  
  COMMENTS:        This is a GRB.  
  COMMENTS:        This trigger occurred at longitude,latitude = 38.05,-17.96 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Mon 04 Apr 22 11:58:07 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     1101133,   Seg_Num: 0
  GRB_RA:           50.448d {+03h 21m 47s} (J2000),
                    50.750d {+03h 23m 00s} (current),
                    49.770d {+03h 19m 05s} (1950)
  GRB_DEC:         +10.005d {+10d 00' 16"} (J2000),
                   +10.083d {+10d 04' 59"} (current),
                    +9.826d {+09d 49' 33"} (1950)
  GRB_DATE:        19673 TJD;    94 DOY;   22/04/04
  GRB_TIME:        42870.42 SOD {11:54:30.42} UT
  TRIGGER_INDEX:   450
  GRB_PHI:         -44.79 [deg]
  GRB_THETA:        36.00 [deg]
  DELTA_TIME:      -11.00 [sec]
  TRIGGER_DUR:     4.096 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     10.58 [sigma]
  IMAGE_SIGNIF:    7.50 [sigma]
  LC_URL:          sw01101133000msb.lc
  SUN_POSTN:        13.54d {+00h 54m 09s}   +5.79d {+05d 47' 35"}
  SUN_DIST:         37.08 [deg]   Sun_angle= -2.5 [hr] (East of Sun)
  MOON_POSTN:       49.92d {+03h 19m 40s}  +18.40d {+18d 24' 02"}
  MOON_DIST:         8.36 [deg]
  MOON_ILLUM:      10 [%]
  GAL_COORDS:      172.58,-37.97 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:       50.69, -8.20 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Lightcurve.  
  COMMENTS:           
  COMMENTS:        The next comments were copied from the BAT_POS Notice:  
  COMMENTS:        This is a rate trigger.  
  COMMENTS:        A point_source was found.  
  COMMENTS:        This does not match any source in the on-board catalog.  
  COMMENTS:        This does not match any source in the ground catalog.  
  COMMENTS:        This is a GRB.  
  COMMENTS:        This trigger occurred at longitude,latitude = 38.05,-17.96 [deg].  
  

  
• GCN Circular #31828
  S. B. Cenko (GSFC), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), J.D. Gropp (PSU), K. L. Page (U Leicester) and T. M. Parsotan (GSFC/UMBC/CRESSTII) report on behalf of the Neil Gehrels Swift Observatory Team:
  At 11:54:30 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 220404A (trigger=1101133). The BAT on-board calculated location is RA, Dec 50.448, +10.005 which is

     RA(J2000) = 03h 21m 47s
     Dec(J2000) = +10d 00' 16"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 10 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~2 sec after the trigger.
  Due to a Sun observing constraint, Swift cannot slew to the BAT position until 20:40 UT on 2022 June 28. There will thus be no XRT or UVOT data for this trigger before this time.
  Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
• GCN Circular #31838
  C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team):
  Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 220404A (trigger #1101133) (Cenko, et al., GCN Circ. 31828). The BAT ground-calculated position is RA, Dec = 50.413, 10.001 deg which is

     RA(J2000)  =  03h 21m 39.0s
     Dec(J2000) = +10d 00' 03.4"
  

  with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 47%.
  The mask-weighted light curve shows a weak peak starts at T0 and ends at T+3 s. There is a hint of a emission around T+5 s. T90 (15-350 keV) is 2.54 +- 0.66 sec (estimated error including systematics).
  The time-averaged spectrum from T+0.26 to T+2.98 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.90 +- 0.36. The fluence in the 15-150 keV band is 1.4 +- 0.3 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.15 sec in the 15-150 keV band is 1.1 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
  The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1101133/BA/