Gamma-ray Burst 040423

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:          GCN/HETE BURST POSITION NOTICE
  NOTICE_DATE:    Fri 23 Apr 04 09:56:25 UT
  NOTICE_TYPE:    HETE S/C_Alert
  TRIGGER_NUM:    3175,   Seq_Num: 1
  GRB_DATE:       13118 TJD;   114 DOY;   04/04/23
  GRB_TIME:       35675.69 SOD {09:54:35.69} UT
  TRIGGER_SOURCE: Trigger on the 25-400 keV band.
  GAMMA_RATE:     153  [cnts/s]  on a 1.300 [sec] timescale
  SC_-Z_RA:       194 [deg]
  SC_-Z_DEC:      -14 [deg]
  SC_LONG:        146 [deg East]
  SUN_POSTN:       31.35d {+02h 05m 24s}  +12.71d {+12d 42' 38"}
  MOON_POSTN:      74.58d {+04h 58m 19s}  +25.81d {+25d 48' 30"}
  MOON_ILLUM:     13 [%]
  COMMENTS:       Probable GRB.
  

• GCN/BACODINE POSITION NOTICE
  

   
  TITLE:          GCN/HETE BURST POSITION NOTICE
  NOTICE_DATE:    Fri 23 Apr 04 10:07:57 UT
  NOTICE_TYPE:    HETE S/C_Last
  TRIGGER_NUM:    3175,   Seq_Num: 2
  GRB_DATE:       13118 TJD;   114 DOY;   04/04/23
  GRB_TIME:       35675.69 SOD {09:54:35.69} UT
  TRIGGER_SOURCE: Trigger on the 25-400 keV band.
  GAMMA_RATE:     153  [cnts/s]  on a 1.300 [sec] timescale
  SC_-Z_RA:       194 [deg]
  SC_-Z_DEC:      -14 [deg]
  SC_LONG:        146 [deg East]
  SUN_POSTN:       31.35d {+02h 05m 24s}  +12.71d {+12d 42' 38"}
  MOON_POSTN:      74.58d {+04h 58m 19s}  +25.81d {+25d 48' 30"}
  MOON_ILLUM:     13 [%]
  COMMENTS:       Probable GRB.
  COMMENTS:       There is no position known for this trigger at this time. 
  

• GCN/BACODINE POSITION NOTICE
  

  TITLE:          GCN/HETE BURST POSITION NOTICE
  NOTICE_DATE:    Sat 24 Apr 04 13:15:34 UT
  NOTICE_TYPE:    HETE Ground Analysis
  TRIGGER_NUM:    3175,   Seq_Num: 3
  GRB_DATE:       13118 TJD;   114 DOY;   04/04/23
  GRB_TIME:       35675.69 SOD {09:54:35.69} UT
  TRIGGER_SOURCE: Trigger on the 25-400 keV band.
  GAMMA_RATE:     153  [cnts/s]  on a 1.300 [sec] timescale
  SC_-Z_RA:       193 [deg]
  SC_-Z_DEC:      -14 [deg]
  SC_LONG:        146 [deg East] 
  SXC_CNTR_RA:    226.684d {+15h 06m 44s} (J2000),
                  226.747d {+15h 06m 59s} (current),
                  225.951d {+15h 03m 48s} (1950) 
  SXC_CNTR_DEC:   -24.794d {-24d 47' 36"} (J2000),
                  -24.810d {-24d 48' 36"} (current),
                  -24.601d {-24d 36' 04"} (1950)
  SXC_CORNER1:    227.4440 -30.3110 [deg]
  SXC_CORNER2:    225.9770 -19.2650 [deg]
  SXC_CORNER3:    225.9250 -19.2740 [deg]
  SXC_CORNER4:    227.3890 -30.3250 [deg] 
  SXC_MAX_SIZE:   666.97 [arcmin] diameter 
  SXC_LOC_SN:     4 sig/noise (pt src in image)
  SUN_POSTN:       31.35d {+02h 05m 24s}  +12.71d {+12d 42' 38"}
  SUN_DIST:       161.09 [deg] 
  MOON_POSTN:      74.58d {+04h 58m 19s}  +25.81d {+25d 48' 30"}
  MOON_DIST:      154.87 [deg]
  MOON_ILLUM:     13 [%]
  GAL_COORDS:     338.10,28.68 [deg] galactic lon,lat of the burst
  ECL_COORDS:     231.14,-7.01 [deg] ecliptic lon,lat of the burst
  COMMENTS:       Definite GRB.  
  COMMENTS:       Burst_Validity flag is true.    
  COMMENTS:       SXC data refined since S/C_Last Notice.
  

• GCN notice #2579
  GRB 040423 (=H3175): A Long GRB Localized by HETE
  M. Boer, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on behalf of the HETE Science Team;
  T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, M. Matsuoka, Y. Nakagawa, T. Sakamoto, R. Sato, Y. Shirasaki, M. Suzuki, T. Tamagawa, K. Torii, Y. Urata, T. Yamazaki, Y. Yamamoto, and A. Yoshida, on behalf of the HETE WXM Team;
  N. Butler, G. Crew, J. Doty, A. Dullighan, G. Prigozhin, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams;
  J-F Olive, J-P Dezalay, C. Barraud, and K. Hurley, on behalf of the HETE FREGATE Team;
  report:
  At 09:54:35.69 UTC (35675.69s UT) on 2004 April 23, the FREGATE, WXM, and SXC instruments on HETE detected trigger H3175, a long GRB.
  The burst triggered in the FREGATE 30-400 keV band. The flight localization by WXM was not distributed automatically, due to the low image S/N in the WXM Y-camera.
  Ground analysis confirmed that the burst was detected and localizable with the WXM X camera, but was out of the field-of-view of the WXM Y-camera. The burst was also in the SXC field-of-view. Since the trigger time occurred in orbit twilight, scattered sunlight still contaminated a major portion of SXC CCD area. Nonetheless, an SXC X-location, but not a Y-location, was derived from the uncontaminated CCD area. Consequently it has been possible to derive an 11-degree by 3-arcminute 1-dimensional error box, whose long dimension is constrained by the relative count rates observed on the wires of the WXM X detector.
  The localization can be expressed as a 90% confidence rectangle whose corners lie at J2000 coordinates:

  R.A. = +15h 09m 46.6s, Dec. = -30d 18' 36"
  R.A. = +15h 03m 54.6s, Dec. = -19d 15' 54"
  R.A. = +15h 03m 42.0s, Dec. = -19d 16' 27"
  R.A. = +15h 09m 33.4s, Dec. = -30d 19' 30"
  

  The T90 duration of the burst was 30s in the FREGATE 30-400 keV energy band. The fluence of the burst was 6E-06 erg cm^-2 in the 25-100 keV band, and the peak flux was 6E-8 erg cm^-2 s^-1 in the 8-30 keV band.
  A light curve, automated spectral fits, and a skymap for GRB040423 are provided at the following URL: http://space.mit.edu/HETE/Bursts/GRB040423
  This message may be cited.