Gamma-ray Burst 240504A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 May 24 05:13:22 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      48
TRIGGER_NUM:     736492377
GRB_RA:           66.767d {+04h 27m 04s} (J2000),
                  67.070d {+04h 28m 17s} (current),
                  66.145d {+04h 24m 35s} (1950)
GRB_DEC:          -4.117d {-04d 07' 00"} (J2000),
                  -4.064d {-04d 03' 48"} (current),
                  -4.228d {-04d 13' 39"} (1950)
GRB_ERROR:       10.10 [deg radius, statistical plus systematic]
GRB_INTEN:       349 [cnts/sec]
DATA_SIGNIF:     12.50 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        20434 TJD;   125 DOY;   24/05/04
GRB_TIME:        18772.64 SOD {05:12:52.64} UT
GRB_PHI:          28.98 [deg]
GRB_THETA:        60.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      0.54
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      91%  GRB
2nd_MOST_LIKELY:   4%  GRO_J0422_32
DETECTORS:       1,1,0, 0,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        41.78d {+02h 47m 07s}  +16.11d {+16d 06' 35"}
SUN_DIST:         32.13 [deg]   Sun_angle= -1.7 [hr] (East of Sun)
MOON_POSTN:      352.22d {+23h 28m 53s}   -5.60d {-05d 35' 43"}
MOON_DIST:        74.55 [deg]
MOON_ILLUM:      20 [%]
GAL_COORDS:      198.73,-33.76 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       64.16,-25.50 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 193.98,-7.45 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 May 24 05:13:31 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      60
TRIGGER_NUM:     736492377
GRB_RA:           71.650d {+04h 46m 36s} (J2000),
                  71.933d {+04h 47m 44s} (current),
                  71.070d {+04h 44m 17s} (1950)
GRB_DEC:         -12.833d {-12d 49' 59"} (J2000),
                 -12.791d {-12d 47' 26"} (current),
                 -12.922d {-12d 55' 19"} (1950)
GRB_ERROR:       4.98 [deg radius, statistical plus systematic]
GRB_INTEN:       551 [cnts/sec]
DATA_SIGNIF:     57.70 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        20434 TJD;   125 DOY;   24/05/04
GRB_TIME:        18772.64 SOD {05:12:52.64} UT
GRB_PHI:          41.00 [deg]
GRB_THETA:        60.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.64
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       1,1,0, 0,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        41.78d {+02h 47m 07s}  +16.11d {+16d 06' 35"}
SUN_DIST:         41.52 [deg]   Sun_angle= -2.0 [hr] (East of Sun)
MOON_POSTN:      352.22d {+23h 28m 54s}   -5.59d {-05d 35' 40"}
MOON_DIST:        78.76 [deg]
MOON_ILLUM:      20 [%]
GAL_COORDS:      210.69,-33.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       68.03,-34.88 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 193.98,-7.45 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 May 24 05:13:40 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      59
TRIGGER_NUM:     736492377
GRB_RA:           66.570d {+04h 26m 17s} (J2000),
                  66.869d {+04h 27m 29s} (current),
                  65.956d {+04h 23m 50s} (1950)
GRB_DEC:          -5.970d {-05d 58' 11"} (J2000),
                  -5.916d {-05d 54' 58"} (current),
                  -6.082d {-06d 04' 54"} (1950)
GRB_ERROR:       3.05 [deg radius, statistical only]
DATA_SIGNIF:     29.20 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        20434 TJD;   125 DOY;   24/05/04
GRB_TIME:        18772.64 SOD {05:12:52.64} UT
GRB_PHI:          31.00 [deg]
GRB_THETA:        61.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:        41.78d {+02h 47m 07s}  +16.11d {+16d 06' 35"}
SUN_DIST:         33.19 [deg]   Sun_angle= -1.7 [hr] (East of Sun)
MOON_POSTN:      352.22d {+23h 28m 54s}   -5.59d {-05d 35' 38"}
MOON_DIST:        74.21 [deg]
MOON_ILLUM:      20 [%]
GAL_COORDS:      200.56,-34.84 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       63.58,-27.29 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_736492377.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:     Sat 04 May 24 05:14:23 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      1
TRIGGER_NUM:     736492377
GRB_RA:           64.370d {+04h 17m 29s} (J2000),
                  64.669d {+04h 18m 41s} (current),
                  63.756d {+04h 15m 02s} (1950)
GRB_DEC:          -6.060d {-06d 03' 35"} (J2000),
                  -6.002d {-06d 00' 05"} (current),
                  -6.182d {-06d 10' 53"} (1950)
GRB_ERROR:       2.50 [deg radius, statistical only]
DATA_SIGNIF:     30.20 [sigma]
DATA_INTERVAL:   5.120 [sec]
GRB_DATE:        20434 TJD;   125 DOY;   24/05/04
GRB_TIME:        18772.64 SOD {05:12:52.64} UT
GRB_PHI:          30.00 [deg]
GRB_THETA:        63.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        41.78d {+02h 47m 07s}  +16.11d {+16d 06' 36"}
SUN_DIST:         31.66 [deg]   Sun_angle= -1.5 [hr] (East of Sun)
MOON_POSTN:      352.23d {+23h 28m 55s}   -5.59d {-05d 35' 25"}
MOON_DIST:        72.01 [deg]
MOON_ILLUM:      20 [%]
GAL_COORDS:      199.34,-36.79 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       61.14,-26.97 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_736492377.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:     Sat 04 May 24 05:14:45 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      2
TRIGGER_NUM:     736492377
GRB_RA:           65.120d {+04h 20m 29s} (J2000),
                  65.415d {+04h 21m 40s} (current),
                  64.513d {+04h 18m 03s} (1950)
GRB_DEC:          -7.610d {-07d 36' 35"} (J2000),
                  -7.553d {-07d 33' 11"} (current),
                  -7.728d {-07d 43' 41"} (1950)
GRB_ERROR:       1.92 [deg radius, statistical only]
DATA_SIGNIF:     52.30 [sigma]
DATA_INTERVAL:   7.168 [sec]
GRB_DATE:        20434 TJD;   125 DOY;   24/05/04
GRB_TIME:        18772.64 SOD {05:12:52.64} UT
GRB_PHI:          32.00 [deg]
GRB_THETA:        63.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        41.78d {+02h 47m 07s}  +16.11d {+16d 06' 36"}
SUN_DIST:         33.28 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:      352.23d {+23h 28m 56s}   -5.59d {-05d 35' 19"}
MOON_DIST:        72.65 [deg]
MOON_ILLUM:      20 [%]
GAL_COORDS:      201.48,-36.89 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       61.63,-28.63 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_736492377.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:     Sat 04 May 24 05:14:35 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      3
TRIGGER_NUM:     736492377
GRB_RA:           65.510d {+04h 22m 02s} (J2000),
                  65.804d {+04h 23m 13s} (current),
                  64.907d {+04h 19m 38s} (1950)
GRB_DEC:          -8.350d {-08d 20' 59"} (J2000),
                  -8.294d {-08d 17' 38"} (current),
                  -8.467d {-08d 28' 00"} (1950)
GRB_ERROR:       2.16 [deg radius, statistical only]
DATA_SIGNIF:     69.90 [sigma]
DATA_INTERVAL:   9.216 [sec]
GRB_DATE:        20434 TJD;   125 DOY;   24/05/04
GRB_TIME:        18772.64 SOD {05:12:52.64} UT
GRB_PHI:          33.00 [deg]
GRB_THETA:        63.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        41.78d {+02h 47m 07s}  +16.11d {+16d 06' 36"}
SUN_DIST:         34.07 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:      352.23d {+23h 28m 56s}   -5.59d {-05d 35' 22"}
MOON_DIST:        72.99 [deg]
MOON_ILLUM:      20 [%]
GAL_COORDS:      202.52,-36.90 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       61.91,-29.43 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_736492377.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:     Sat 04 May 24 05:14:54 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      4
TRIGGER_NUM:     736492377
GRB_RA:           64.230d {+04h 16m 55s} (J2000),
                  64.525d {+04h 18m 06s} (current),
                  63.624d {+04h 14m 30s} (1950)
GRB_DEC:          -7.690d {-07d 41' 23"} (J2000),
                  -7.631d {-07d 37' 52"} (current),
                  -7.812d {-07d 48' 44"} (1950)
GRB_ERROR:       1.12 [deg radius, statistical only]
DATA_SIGNIF:     73.70 [sigma]
DATA_INTERVAL:   18.432 [sec]
GRB_DATE:        20434 TJD;   125 DOY;   24/05/04
GRB_TIME:        18772.64 SOD {05:12:52.64} UT
GRB_PHI:          32.00 [deg]
GRB_THETA:        64.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        41.78d {+02h 47m 07s}  +16.11d {+16d 06' 36"}
SUN_DIST:         32.72 [deg]   Sun_angle= -1.5 [hr] (East of Sun)
MOON_POSTN:      352.24d {+23h 28m 57s}   -5.59d {-05d 35' 16"}
MOON_DIST:        71.76 [deg]
MOON_ILLUM:      20 [%]
GAL_COORDS:      201.04,-37.71 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       60.63,-28.54 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_736492377.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:     Sat 04 May 24 05:22:12 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     736492377
GRB_RA:           64.620d {+04h 18m 29s} (J2000),
                  64.913d {+04h 19m 39s} (current),
                  64.018d {+04h 16m 04s} (1950)
GRB_DEC:          -8.660d {-08d 39' 35"} (J2000),
                  -8.602d {-08d 36' 07"} (current),
                  -8.781d {-08d 46' 49"} (1950)
GRB_ERROR:       2.37 [deg radius, statistical only]
GRB_DATE:        20434 TJD;   125 DOY;   24/05/04
GRB_TIME:        18772.64 SOD {05:12:52.64} UT
GRB_PHI:          33.00 [deg]
GRB_THETA:        64.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        41.79d {+02h 47m 09s}  +16.11d {+16d 06' 41"}
SUN_DIST:         33.69 [deg]   Sun_angle= -1.5 [hr] (East of Sun)
MOON_POSTN:      352.30d {+23h 29m 12s}   -5.55d {-05d 33' 11"}
MOON_DIST:        72.03 [deg]
MOON_ILLUM:      20 [%]
GAL_COORDS:      202.35,-37.82 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       60.85,-29.57 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_locplot_all_bn240504217.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 NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 May 24 06:40:05 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     736492377
GRB_RA:           65.880d {+04h 23m 31s} (J2000),
                  66.179d {+04h 24m 43s} (current),
                  65.266d {+04h 21m 04s} (1950)
GRB_DEC:          -5.950d {-05d 56' 59"} (J2000),
                  -5.895d {-05d 53' 40"} (current),
                  -6.065d {-06d 03' 53"} (1950)
GRB_ERROR:       3.34 [deg radius, statistical only]
GRB_DATE:        20434 TJD;   125 DOY;   24/05/04
GRB_TIME:        18772.64 SOD {05:12:52.64} UT
GRB_PHI:          30.36 [deg]
GRB_THETA:        61.51 [deg]
E_RANGE:         50.000 - 300.000 [keV]
LOC_ALGORITHM:   415 (Gnd S/W Version number)
SUN_POSTN:        41.84d {+02h 47m 21s}  +16.13d {+16d 07' 37"}
SUN_DIST:         32.64 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:      353.00d {+23h 32m 01s}   -5.18d {-05d 10' 50"}
MOON_DIST:        72.78 [deg]
MOON_ILLUM:      20 [%]
GAL_COORDS:      200.13,-35.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       62.82,-27.14 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_locplot_all_bn240504217.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 has human-in-the-loop processing.

GCN Circular #36387
The Fermi GBM team reports the detection of a likely LONG GRB
At 05:12:52 UT on 4 May 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240504A (trigger 736492377.637702 / 240504217).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 64.6, Dec = -8.7 (J2000 degrees, equivalent to J2000 04h 18m, -8d 41'), with a statistical uncertainty of 2.4 degrees.
The angle from the Fermi LAT boresight is 64.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_skymap_all_bn240504217.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_healpix_all_bn240504217.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240504217/quicklook/glg_lc_medres34_bn240504217.gif
GCN Circular #36388
T. Preis, B. Biltzinger, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 736492377 at 05:12:52 on 04 May 2024 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60).
The best-fit position is:
```
RA(2000.0) = 65.9 deg
Decl.(2000.0) = -9.1 deg
```
The 1 sigma statistical error radius is 1.9 deg. We estimate an additional systematic error of 1 deg.
Further details are available at: https://grb.mpe.mpg.de/grb/GRB240504217/
The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB240504217/healpix
The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB240504217/json
GCN Circular #36392
V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gress, N.M. Budnev, O.Ershova (Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich (Blagoveschensk Educational State University)
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 240504A ( Fermi GBM team, GCN 36387) errorbox 42875 sec after notice time and 42910 sec after trigger time at 2024-05-04 17:08:02 UT, with upper limit up to 17.4 mag. Observations started at twilight. The observations began at zenith distance = 74 deg. The sun altitude is -15.3 deg.
The galactic latitude b = -35 deg., longitude l = 200 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2442874
We obtain a following upper limits.
```
Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   42940 | 2024-05-04 17:08:02 |         MASTER-SAAO | (04h 16m 43.98s , -08d 23m 19.2s) |   C |    60 | 17.3 |        
   43659 | 2024-05-04 17:20:01 |         MASTER-SAAO | (04h 24m 57.17s , -08d 24m 29.7s) |   C |    60 | 17.4 |        
   43979 | 2024-05-04 17:25:21 |         MASTER-SAAO | (04h 17m 03.18s , -08d 23m 43.8s) |   C |    60 | 16.9 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #36401
Samuele Ronchini (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 240504A onboard (T0: 2024-05-04T05:12:52.64 UTC, Fermi trig 736492377)
The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 74.5 in a 16.384 s analysis time bin, starting at T0.
NITRATES results are consistent with a burst coming from outside the FOV, with DeltaLLHOut of -208.
See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.
GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
GCN Circular #36407
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team,
D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko, 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,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT 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 240504A (Fermi-GBM detection: The Fermi GBM team, GCN 36387; BALROG localization: Preis et al., GCN 36388; Swift-BAT/GUANO detection: Ronchini et al., GCN 36401) was detected by Fermi (GBM trigger 736492377), Konus-Wind, INTEGRAL (SPI-ACS), Swift (BAT), and Mars-Odyssey (HEND) at about 18773 s UT (05:12:53). The burst was outside the coded field of view of the BAT.
We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:
```
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
   64.767 (04h 19m 04s) -10.087 (-10d 05' 13")
 Corners:
   64.587 (04h 18m 21s) -11.558 (-11d 33' 29")
   64.659 (04h 18m 38s) -11.560 (-11d 33' 36")
   64.926 (04h 19m 42s)  -8.615 ( -8d 36' 53")
   64.854 (04h 19m 25s)  -8.613 ( -8d 36' 47")
 ---------------------------------------------
```
The error box area is 756 sq. arcmin, and its maximum dimension is 2.96 deg (the minimum one is 4.3 arcmin). The Sun distance was 35 deg.
The IPN localization is consistent with, but reduces the area of, the Fermi-GBM final and BALROG localizations.
This localization may be improved.
A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB240504_T18769/IPN/
The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
GCN Circular #36416
B. Mailyan (Florida tech) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 05:12:52.64 UT on 04 May 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240504A (trigger 736492377/240504217). which was also detected by Swift/BAT-GUANO (S. Ronchini et al. 2024, GCN 36401). The Fermi GBM on-ground location is consistent with the Fermi GBM final position notice (GCN 36387).
The angle from the Fermi LAT boresight is 64 degrees.
The GBM light curve consists of a single emission episode with a duration (T90) of about 19 s (50-300 keV). The time-averaged spectrum from T0+0.003 to T0+20.096 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.12 +/- 0.02 and the cutoff energy, parameterized as Epeak, is 682.50 +/- 52.10. A Band function with Epeak 665.80 +/- 55.40, Alpha -1.11 +/- 0.02, Beta -3.01 +/- 0.77 fits the spectrum equally well.
The event fluence (10-1000 keV) in this time interval is (2.26 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+6.7 s in the 10-1000 keV band is 11.5 +/- 0.3 ph/s/cm^2.
We note that there is a second FRED-like peak about 100s after the reported event here that seems to be related. However, due to a contemporaneous solar flare, we are unable to disentangle the two events and thus we omit this portion of the burst due to contamination. We note that the burst could have a T90 of 250s, but other instruments are required to confirm this.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular #36520
A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration.
The long-duration GRB 240504A (Fermi/GBM detection: GCN 36416; Swift/BAT-GUANO detection: GCN 36401; Konus/Wind detection trigger at 2024-05-04 05:12:49.901 UT; INTEGRAL/SPI-ACS peak detection at 2024-05-04 ~04:03:45 UT) was detected by the GRB detectors on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).
The data acquisition was performed by the GRB detector units no. 0 and no. 1. The detection was confirmed at the peak time 2024-05-04 05:12:51 (05:12:52) UTC. The T90 duration is 15 s (13 s) and the significance during T90 reaches 24 sigma (14 sigma) for detector unit no. 0 (no. 1).
The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB240504A_GCN_VZLUSAT2.pdf
We note that the light curve measured by VZLUSAT-2 is shifted by approximately 8 s with respect to light curves obtained by other missions. The cause of the on-board clock slip is being fixed.
All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/. The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral.

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Jochen Greiner, last update: 20-May-2024 [Disclaimer]