Gamma-ray Burst 250703A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 03 Jul 25 09:07:43 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      59
TRIGGER_NUM:     773226456
GRB_RA:          338.233d {+22h 32m 56s} (J2000),
                 338.535d {+22h 34m 08s} (current),
                 337.642d {+22h 30m 34s} (1950)
GRB_DEC:         +25.200d {+25d 11' 60"} (J2000),
                 +25.332d {+25d 19' 55"} (current),
                 +24.942d {+24d 56' 31"} (1950)
GRB_ERROR:       5.60 [deg radius, statistical plus systematic]
GRB_INTEN:       544 [cnts/sec]
DATA_SIGNIF:     30.60 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        20859 TJD;   184 DOY;   25/07/03
GRB_TIME:        32851.43 SOD {09:07:31.43} UT
GRB_PHI:         105.00 [deg]
GRB_THETA:       130.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.55
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      82%  GRB
2nd_MOST_LIKELY:  11%  Distant Particles
DETECTORS:       0,0,1, 0,0,0, 0,0,0, 0,1,0, 0,0,
SUN_POSTN:       102.72d {+06h 50m 53s}  +22.92d {+22d 55' 12"}
SUN_DIST:        107.53 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      195.73d {+13h 02m 56s}   -9.19d {-09d 11' 07"}
MOON_DIST:       141.17 [deg]
MOON_ILLUM:      56 [%]
GAL_COORDS:       87.34,-27.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      350.64, 31.61 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_lc_medres34_bn250703380.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 12.38,-13.62 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 03 Jul 25 09:07:34 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      46
TRIGGER_NUM:     773226456
GRB_RA:          338.200d {+22h 32m 48s} (J2000),
                 338.502d {+22h 34m 00s} (current),
                 337.609d {+22h 30m 26s} (1950)
GRB_DEC:         +25.317d {+25d 19' 00"} (J2000),
                 +25.449d {+25d 26' 55"} (current),
                 +25.059d {+25d 03' 31"} (1950)
GRB_ERROR:       5.22 [deg radius, statistical plus systematic]
GRB_INTEN:       472 [cnts/sec]
DATA_SIGNIF:     18.90 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        20859 TJD;   184 DOY;   25/07/03
GRB_TIME:        32851.43 SOD {09:07:31.43} UT
GRB_PHI:         105.00 [deg]
GRB_THETA:       130.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.64
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      84%  GRB
2nd_MOST_LIKELY:  10%  Distant Particles
DETECTORS:       0,0,1, 0,0,0, 0,0,0, 0,1,0, 0,0,
SUN_POSTN:       102.72d {+06h 50m 53s}  +22.92d {+22d 55' 12"}
SUN_DIST:        107.48 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      195.73d {+13h 02m 56s}   -9.18d {-09d 11' 05"}
MOON_DIST:       141.11 [deg]
MOON_ILLUM:      56 [%]
GAL_COORDS:       87.39,-27.82 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      350.67, 31.73 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_lc_medres34_bn250703380.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 12.38,-13.62 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 03 Jul 25 09:07:49 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     773226456
GRB_RA:          337.550d {+22h 30m 12s} (J2000),
                 337.852d {+22h 31m 24s} (current),
                 336.959d {+22h 27m 50s} (1950)
GRB_DEC:         +24.760d {+24d 45' 36"} (J2000),
                 +24.891d {+24d 53' 29"} (current),
                 +24.503d {+24d 30' 12"} (1950)
GRB_ERROR:       1.45 [deg radius, statistical only]
DATA_SIGNIF:     35.30 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        20859 TJD;   184 DOY;   25/07/03
GRB_TIME:        32851.43 SOD {09:07:31.43} UT
GRB_PHI:         106.00 [deg]
GRB_THETA:       130.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       102.72d {+06h 50m 53s}  +22.92d {+22d 55' 12"}
SUN_DIST:        108.29 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      195.74d {+13h 02m 57s}   -9.19d {-09d 11' 08"}
MOON_DIST:       140.71 [deg]
MOON_ILLUM:      56 [%]
GAL_COORDS:       86.48,-27.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      349.76, 31.48 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_lc_medres34_bn250703380.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_773226456.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 03 Jul 25 09:08:20 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      0
TRIGGER_NUM:     773226456
GRB_RA:          337.520d {+22h 30m 05s} (J2000),
                 337.822d {+22h 31m 17s} (current),
                 336.929d {+22h 27m 43s} (1950)
GRB_DEC:         +24.890d {+24d 53' 24"} (J2000),
                 +25.021d {+25d 01' 17"} (current),
                 +24.633d {+24d 37' 60"} (1950)
GRB_ERROR:       1.01 [deg radius, statistical only]
DATA_SIGNIF:     29.30 [sigma]
DATA_INTERVAL:   3.072 [sec]
GRB_DATE:        20859 TJD;   184 DOY;   25/07/03
GRB_TIME:        32851.43 SOD {09:07:31.43} UT
GRB_PHI:         106.00 [deg]
GRB_THETA:       130.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       102.72d {+06h 50m 53s}  +22.92d {+22d 55' 12"}
SUN_DIST:        108.23 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      195.74d {+13h 02m 57s}   -9.19d {-09d 11' 15"}
MOON_DIST:       140.64 [deg]
MOON_ILLUM:      56 [%]
GAL_COORDS:       86.54,-27.82 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      349.80, 31.61 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_lc_medres34_bn250703380.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_773226456.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 03 Jul 25 09:08:30 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      1
TRIGGER_NUM:     773226456
GRB_RA:          337.530d {+22h 30m 07s} (J2000),
                 337.832d {+22h 31m 20s} (current),
                 336.939d {+22h 27m 45s} (1950)
GRB_DEC:         +24.850d {+24d 51' 00"} (J2000),
                 +24.981d {+24d 58' 53"} (current),
                 +24.593d {+24d 35' 36"} (1950)
GRB_ERROR:       1.00 [deg radius, statistical only]
DATA_SIGNIF:     36.10 [sigma]
DATA_INTERVAL:   5.120 [sec]
GRB_DATE:        20859 TJD;   184 DOY;   25/07/03
GRB_TIME:        32851.43 SOD {09:07:31.43} UT
GRB_PHI:         106.00 [deg]
GRB_THETA:       130.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       102.72d {+06h 50m 53s}  +22.92d {+22d 55' 12"}
SUN_DIST:        108.25 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      195.74d {+13h 02m 58s}   -9.19d {-09d 11' 18"}
MOON_DIST:       140.66 [deg]
MOON_ILLUM:      56 [%]
GAL_COORDS:       86.53,-27.86 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      349.79, 31.57 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_lc_medres34_bn250703380.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_773226456.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 03 Jul 25 09:17:01 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     773226456
GRB_RA:          337.570d {+22h 30m 17s} (J2000),
                 337.870d {+22h 31m 29s} (current),
                 336.982d {+22h 27m 56s} (1950)
GRB_DEC:         +26.140d {+26d 08' 24"} (J2000),
                 +26.271d {+26d 16' 17"} (current),
                 +25.883d {+25d 52' 60"} (1950)
GRB_ERROR:       1.18 [deg radius, statistical only]
GRB_DATE:        20859 TJD;   184 DOY;   25/07/03
GRB_TIME:        32851.43 SOD {09:07:31.43} UT
GRB_PHI:         105.00 [deg]
GRB_THETA:       131.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       102.73d {+06h 50m 55s}  +22.92d {+22d 55' 10"}
SUN_DIST:        107.44 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      195.80d {+13h 03m 13s}   -9.22d {-09d 13' 12"}
MOON_DIST:       140.27 [deg]
MOON_ILLUM:      56 [%]
GAL_COORDS:       87.40,-26.82 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      350.49, 32.72 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_lc_medres34_bn250703380.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_locplot_all_bn250703380.png
COMMENTS:        Fermi-GBM Final Position.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.  
COMMENTS:        This notice was generated completely by automated pipeline processing.  
COMMENTS:        This is likely a Long GRB.

GCN Circular #40909
The Fermi GBM team reports the detection of a likely LONG GRB
At 09:07:31 UT on 3 Jul 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250703A (trigger 773226456.426922 / 250703380).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 337.6, Dec = 26.1 (J2000 degrees, equivalent to J2000 22h 30m, 26d 06'), with a statistical uncertainty of 1.2 degrees.
The angle from the Fermi LAT boresight is 131.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_skymap_all_bn250703380.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_healpix_all_bn250703380.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_lc_medres34_bn250703380.gif
GCN Circular #40915
Sahil Atri (U Roma), Rosa L. Becerra (U Roma), Alan M. Watson (UNAM), Camila Angulo Valdez (UNAM), Nat Butler (ASU), Simone Dichiara (Penn State University), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl López (UNAM), Margarita Pereyra (UNAM) and Eleonora Troja (U Roma) report:
We observed the field of GRB 250703A detected by Fermi/GBM (Fermi GBM Team, GCN Circ. 40909) with the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir (http://ddoti.astroscu.unam.mx) on the night of 2025-07-03 UTC.
DDOTI observed the Fermi/GBM error region, covering about 92% of the statistical error region (Fermi GBM Team, GCN Circ. 40909). DDOTI observed the field of GRB 250703A from 09:19 UTC to 11:22 UTC (from T+ 0.2 h to T+ 2.2 h after the trigger) and obtained a total exposure of 56 minutes, alternating with other scientific programs.
Comparing our observations to the USNO-B1 and Pan-STARRS PS1 DR2 catalogues, we detect no uncatalogued fading sources within the observed field down to a 10-sigma limiting AB magnitude of:
w > 20.8
This value is not corrected for the Galactic extinction.

GCN Circular #40930
V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 250703A ( Fermi GBM team, GCN 40909) errorbox 54105 sec after notice time and 54115 sec after trigger time at 2025-07-04 00:09:27 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 65 deg. The sun altitude is -68.8 deg.
The galactic latitude b = -27 deg., longitude l = 88 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2924032
We obtain a following upper limits.

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   54146 | 2025-07-04 00:09:27 |         MASTER-SAAO | (22h 26m 03.93s , +25d 31m 00.0s) |   C |    60 | 18.5 |        
   54146 | 2025-07-04 00:09:27 |         MASTER-SAAO | (22h 24m 08.95s , +25d 46m 54.4s) |   C |    60 | 18.4 |        
   54360 | 2025-07-04 00:13:01 |         MASTER-SAAO | (22h 34m 58.48s , +25d 30m 12.9s) |   C |    60 | 19.1 |        
   54360 | 2025-07-04 00:13:01 |         MASTER-SAAO | (22h 33m 03.49s , +25d 46m 08.2s) |   C |    60 | 19.0 |        
   54650 | 2025-07-04 00:17:51 |         MASTER-SAAO | (22h 22m 02.32s , +23d 35m 41.4s) |   C |    60 | 19.0 |        
   54744 | 2025-07-04 00:19:25 |         MASTER-SAAO | (22h 30m 48.83s , +23d 37m 23.1s) |   C |    60 | 18.4 |        
   54744 | 2025-07-04 00:19:25 |         MASTER-SAAO | (22h 28m 54.92s , +23d 53m 18.7s) |   C |    60 | 18.4 |        
   54838 | 2025-07-04 00:20:59 |         MASTER-SAAO | (22h 26m 00.65s , +25d 30m 36.9s) |   C |    60 | 17.6 |        
   54838 | 2025-07-04 00:20:59 |         MASTER-SAAO | (22h 24m 05.05s , +25d 46m 32.8s) |   C |    60 | 17.5 |        
   55038 | 2025-07-04 00:24:19 |         MASTER-SAAO | (22h 34m 59.98s , +25d 30m 21.6s) |   C |    60 | 18.7 |        
   55038 | 2025-07-04 00:24:19 |         MASTER-SAAO | (22h 33m 04.25s , +25d 46m 18.0s) |   C |    60 | 18.6 |        
   55530 | 2025-07-04 00:32:31 |         MASTER-SAAO | (22h 22m 03.38s , +23d 35m 59.0s) |   C |    60 | 16.4 |        
   55624 | 2025-07-04 00:34:05 |         MASTER-SAAO | (22h 30m 50.57s , +23d 37m 31.6s) |   C |    60 | 18.2 |        
   55624 | 2025-07-04 00:34:05 |         MASTER-SAAO | (22h 28m 55.96s , +23d 53m 28.4s) |   C |    60 | 18.1 |        
   55717 | 2025-07-04 00:35:38 |         MASTER-SAAO | (22h 26m 03.12s , +25d 30m 45.9s) |   C |    60 | 16.1 |        
   55717 | 2025-07-04 00:35:38 |         MASTER-SAAO | (22h 24m 06.74s , +25d 46m 43.2s) |   C |    60 | 16.1 |        
   58382 | 2025-07-04 01:20:03 |         MASTER-SAAO | (22h 34m 57.08s , +25d 32m 08.2s) |   C |    60 | 17.9 |        
   58382 | 2025-07-04 01:20:03 |         MASTER-SAAO | (22h 33m 00.18s , +25d 47m 59.5s) |   C |    60 | 17.7 |        
   59961 | 2025-07-04 01:46:22 |         MASTER-SAAO | (22h 22m 20.57s , +23d 37m 14.0s) |   C |    60 | 18.6 |        
   59961 | 2025-07-04 01:46:22 |         MASTER-SAAO | (22h 20m 26.03s , +23d 53m 02.5s) |   C |    60 | 18.4 |        
   60055 | 2025-07-04 01:47:56 |         MASTER-SAAO | (22h 31m 09.34s , +23d 37m 00.4s) |   C |    60 | 17.5 |        
   60055 | 2025-07-04 01:47:56 |         MASTER-SAAO | (22h 29m 14.85s , +23d 52m 49.9s) |   C |    60 | 17.3 |        
   60151 | 2025-07-04 01:49:32 |         MASTER-SAAO | (22h 26m 26.43s , +25d 32m 54.5s) |   C |    60 | 16.6 |        
   60151 | 2025-07-04 01:49:32 |         MASTER-SAAO | (22h 24m 30.30s , +25d 48m 45.4s) |   C |    60 | 16.3 |        
   60345 | 2025-07-04 01:52:46 |         MASTER-SAAO | (22h 35m 20.05s , +25d 32m 35.8s) |   C |    60 | 15.5 |        
   60345 | 2025-07-04 01:52:46 |         MASTER-SAAO | (22h 33m 23.77s , +25d 48m 27.9s) |   C |    60 | 15.3 |

Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.

GCN Circular #40976
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team,
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge, and E. Burns on behalf of the Fermi GBM team,
and
W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report:
The long-duration GRB 20250703A (Fermi-GBM detection: Fermi GBM team, GCN Circ. 40909) was detected by Fermi (GBM trigger 773226456), Konus-Wind, and Mars-Odyssey (HEND) at about 32851 s UT (09:07:31).
We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:
```
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  351.240 (23h 24m 58s) +28.375 (+28d 22' 31")
 Corners:
  352.362 (23h 29m 27s) +28.111 (+28d 06' 39")
  350.071 (23h 20m 17s) +28.695 (+28d 41' 42")
  350.131 (23h 20m 32s) +28.603 (+28d 36' 11")
  352.423 (23h 29m 41s) +28.013 (+28d 00' 47")
 ---------------------------------------------
```
The error box area is 0.16 sq. deg, and its maximum dimension is 2.2 deg (the minimum one is 5 arcmin). The Sun distance was 96 deg.
The IPN localization is consistent with, but reduces the area of, the Fermi-GBM localization.
A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB250703_T32851/IPN The HEALPix triangulation map is the multi-order HEALPix in units of probability density.
The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
GCN Circular #40977
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
The long-duration GRB 250703A (Fermi-GBM detection: The Fermi GBM team, GCN 40909; IPN localization Kozyrev et al., GCN 40976) triggered Konus-Wind (KW) at T0=32851.983 s UT (09:07:31.983).
The burst light curve shows a single multi-peaked emission pulse with a total duration of ~4.5 s. The emission is seen up to ~5 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250703_T32851/
As observed by Konus-Wind, the burst had a fluence of (5.86 ± 0.66)x10^-6 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 0.960 s, of (3.81 ± 0.43)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.36 (-0.22,+0.28), the high energy photon index beta = -2.76 (-0.49,+0.27), the peak energy Ep = 147(-15,+15) keV, chi2 = 84/94 dof.
All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.
GCN Circular #40984
L. Cotter,C. McKenna, D. Murphy, C. de Barra, A. Ulyanov, P. McDermott, G. Finneran, M. Doyle, R. Dunwoody, J. Mangan, G. Corcoran, A. Empey, J. Fisher, F. Gibson Kiely, J. Thompson, D. McKeown, A. Martin-Carrillo, L. Hanlon, S. McBreen, on behalf of the EIRSAT-1 team:
EIRSAT-1 reports the detection of the long gamma-ray burst GRB250703A (Fermi-GBM detection GCN 40909; IPN localization GCN 40976; Kounus Wind GCN 40977) by the Gamma-ray Module (GMOD) instrument. The GMOD detection was made, starting at 2025-07-03 09:07:31.6 UTC.
The GMOD light-curve for GRB250703A with 1.2s binning shows a single bright pulse starting at 09:07:31.6 UTC, also visible on the Fermi light-curve.
The spacecraft location at the time of detection was 47.364º N, 32.160º E, at an altitude of 361.2 km. The GMOD light curve for this event can be found here:
https://grb.eirsat1.ie/250703A/250703A_LC_onboard_preliminary.png
EIRSAT-1 is Ireland’s first satellite (Doyle et al. Proceedings of the 4th SSEA, 2022). It is a 2U CubeSat and carries onboard a number of experiments, including the Gamma-Ray Module (GMOD), a novel, compact, gamma-ray detector (Murphy et al, Experimental Astronomy, 53, 961–990, 2022). GMOD consists of a 25 mm × 25 mm × 40 mm Cerium Bromide scintillator coupled to SiPMs and is designed to detect gamma-ray bursts in the ~ 60 keV - 1.5 MeV range. EIRSAT-1 was developed at University College Dublin with support from ESA’s Fly Your Satellite! programme and was launched on 1st December 2023.

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Jochen Greiner, last update: 06-Jul-2025 [Disclaimer]