Gamma-ray Burst 230426A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 26 Apr 23 20:29:29 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     704233744
GRB_RA:           46.683d {+03h 06m 44s} (J2000),
                  46.623d {+03h 06m 30s} (current),
                  46.821d {+03h 07m 17s} (1950)
GRB_DEC:         -75.300d {-75d 17' 59"} (J2000),
                 -75.211d {-75d 12' 38"} (current),
                 -75.491d {-75d 29' 26"} (1950)
GRB_ERROR:       29.35 [deg radius, statistical plus systematic]
GRB_INTEN:       56 [cnts/sec]
DATA_SIGNIF:     4.60 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        20060 TJD;   116 DOY;   23/04/26
GRB_TIME:        73739.97 SOD {20:28:59.97} UT
GRB_PHI:         262.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      3.87
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      49%  GRB
2nd_MOST_LIKELY:  34%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,1,1, 0,0,0, 0,0,
SUN_POSTN:        34.03d {+02h 16m 07s}  +13.64d {+13d 38' 09"}
SUN_DIST:         89.19 [deg]   Sun_angle= -0.8 [hr] (East of Sun)
MOON_POSTN:      118.04d {+07h 52m 11s}  +26.27d {+26d 16' 25"}
MOON_DIST:       110.80 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      292.47,-38.95 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      308.95,-73.92 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_lc_medres34_bn230426853.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 191.62,6.65 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 26 Apr 23 20:29:49 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      70
TRIGGER_NUM:     704233744
GRB_RA:           47.067d {+03h 08m 16s} (J2000),
                  46.807d {+03h 07m 14s} (current),
                  47.649d {+03h 10m 36s} (1950)
GRB_DEC:         -80.400d {-80d 24' 00"} (J2000),
                 -80.311d {-80d 18' 40"} (current),
                 -80.589d {-80d 35' 18"} (1950)
GRB_ERROR:       4.92 [deg radius, statistical plus systematic]
GRB_INTEN:       576 [cnts/sec]
DATA_SIGNIF:     57.80 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        20060 TJD;   116 DOY;   23/04/26
GRB_TIME:        73739.97 SOD {20:28:59.97} UT
GRB_PHI:         255.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      2.04
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      76%  GRB
2nd_MOST_LIKELY:  23%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,1,1, 0,0,0, 0,0,
SUN_POSTN:        34.03d {+02h 16m 07s}  +13.64d {+13d 38' 10"}
SUN_DIST:         94.18 [deg]   Sun_angle= -0.9 [hr] (East of Sun)
MOON_POSTN:      118.05d {+07h 52m 11s}  +26.27d {+26d 16' 23"}
MOON_DIST:       112.82 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      296.37,-34.91 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      292.07,-72.40 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_lc_medres34_bn230426853.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 191.62,6.65 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 26 Apr 23 20:29:38 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     704233744
GRB_RA:           46.517d {+03h 06m 04s} (J2000),
                  46.259d {+03h 05m 02s} (current),
                  47.097d {+03h 08m 23s} (1950)
GRB_DEC:         -80.467d {-80d 28' 00"} (J2000),
                 -80.377d {-80d 22' 37"} (current),
                 -80.657d {-80d 39' 25"} (1950)
GRB_ERROR:       5.83 [deg radius, statistical plus systematic]
GRB_INTEN:       461 [cnts/sec]
DATA_SIGNIF:     23.20 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        20060 TJD;   116 DOY;   23/04/26
GRB_TIME:        73739.97 SOD {20:28:59.97} UT
GRB_PHI:         255.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      2.38
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      76%  GRB
2nd_MOST_LIKELY:  23%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,1,1, 0,0,0, 0,0,
SUN_POSTN:        34.03d {+02h 16m 07s}  +13.64d {+13d 38' 09"}
SUN_DIST:         94.22 [deg]   Sun_angle= -0.8 [hr] (East of Sun)
MOON_POSTN:      118.05d {+07h 52m 11s}  +26.27d {+26d 16' 24"}
MOON_DIST:       112.93 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      296.50,-34.92 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      292.00,-72.29 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_lc_medres34_bn230426853.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 191.62,6.65 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 26 Apr 23 20:30:00 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      93
TRIGGER_NUM:     704233744
GRB_RA:           49.267d {+03h 17m 04s} (J2000),
                  49.004d {+03h 16m 01s} (current),
                  49.856d {+03h 19m 25s} (1950)
GRB_DEC:         -80.133d {-80d 07' 59"} (J2000),
                 -80.048d {-80d 02' 53"} (current),
                 -80.314d {-80d 18' 49"} (1950)
GRB_ERROR:       3.82 [deg radius, statistical plus systematic]
GRB_INTEN:       1860 [cnts/sec]
DATA_SIGNIF:     180.90 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        20060 TJD;   116 DOY;   23/04/26
GRB_TIME:        73739.97 SOD {20:28:59.97} UT
GRB_PHI:         255.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.78
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      85%  GRB
2nd_MOST_LIKELY:  14%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,1,1, 0,0,0, 0,0,
SUN_POSTN:        34.03d {+02h 16m 07s}  +13.64d {+13d 38' 10"}
SUN_DIST:         94.01 [deg]   Sun_angle= -1.0 [hr] (East of Sun)
MOON_POSTN:      118.05d {+07h 52m 12s}  +26.27d {+26d 16' 22"}
MOON_DIST:       112.37 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      295.81,-34.89 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      292.29,-72.85 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_lc_medres34_bn230426853.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 191.62,6.65 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 26 Apr 23 20:29:47 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     704233744
GRB_RA:           19.260d {+01h 17m 02s} (J2000),
                  19.302d {+01h 17m 13s} (current),
                  19.180d {+01h 16m 43s} (1950)
GRB_DEC:         -80.580d {-80d 34' 47"} (J2000),
                 -80.457d {-80d 27' 26"} (current),
                 -80.843d {-80d 50' 33"} (1950)
GRB_ERROR:       6.81 [deg radius, statistical only]
DATA_SIGNIF:     8.50 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        20060 TJD;   116 DOY;   23/04/26
GRB_TIME:        73739.97 SOD {20:28:59.97} UT
GRB_PHI:         253.00 [deg]
GRB_THETA:        46.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:        34.03d {+02h 16m 07s}  +13.64d {+13d 38' 10"}
SUN_DIST:         94.40 [deg]   Sun_angle= 1.0 [hr] (West of Sun)
MOON_POSTN:      118.05d {+07h 52m 11s}  +26.27d {+26d 16' 24"}
MOON_DIST:       117.33 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      301.63,-36.48 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      294.26,-67.91 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_lc_medres34_bn230426853.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_704233744.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
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:     Wed 26 Apr 23 20:29:53 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      73
TRIGGER_NUM:     704233744
GRB_RA:           48.900d {+03h 15m 36s} (J2000),
                  48.637d {+03h 14m 33s} (current),
                  49.489d {+03h 17m 57s} (1950)
GRB_DEC:         -80.183d {-80d 10' 59"} (J2000),
                 -80.098d {-80d 05' 51"} (current),
                 -80.365d {-80d 21' 54"} (1950)
GRB_ERROR:       3.83 [deg radius, statistical plus systematic]
GRB_INTEN:       1797 [cnts/sec]
DATA_SIGNIF:     122.00 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        20060 TJD;   116 DOY;   23/04/26
GRB_TIME:        73739.97 SOD {20:28:59.97} UT
GRB_PHI:         255.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      1.70
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      85%  GRB
2nd_MOST_LIKELY:  14%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,1,1, 0,0,0, 0,0,
SUN_POSTN:        34.03d {+02h 16m 07s}  +13.64d {+13d 38' 10"}
SUN_DIST:         94.04 [deg]   Sun_angle= -1.0 [hr] (East of Sun)
MOON_POSTN:      118.05d {+07h 52m 12s}  +26.27d {+26d 16' 23"}
MOON_DIST:       112.45 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      295.91,-34.89 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      292.24,-72.78 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_lc_medres34_bn230426853.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 191.62,6.65 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 26 Apr 23 20:38:08 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     704233744
GRB_RA:           38.530d {+02h 34m 07s} (J2000),
                  38.229d {+02h 32m 55s} (current),
                  39.218d {+02h 36m 52s} (1950)
GRB_DEC:         -82.400d {-82d 24' 00"} (J2000),
                 -82.298d {-82d 17' 53"} (current),
                 -82.617d {-82d 37' 00"} (1950)
GRB_ERROR:       1.00 [deg radius, statistical only]
GRB_DATE:        20060 TJD;   116 DOY;   23/04/26
GRB_TIME:        73739.97 SOD {20:28:59.97} UT
GRB_PHI:         252.00 [deg]
GRB_THETA:        49.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        34.04d {+02h 16m 09s}  +13.64d {+13d 38' 16"}
SUN_DIST:         95.96 [deg]   Sun_angle= -0.3 [hr] (East of Sun)
MOON_POSTN:      118.12d {+07h 52m 29s}  +26.26d {+26d 15' 40"}
MOON_DIST:       114.67 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      298.97,-33.92 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      287.99,-70.42 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_lc_medres34_bn230426853.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_locplot_all_bn230426853.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:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.

GCN Circular #33684
The Fermi GBM team reports the detection of a likely LONG GRB
At 20:28:59 UT on 26 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230426A (trigger 704233744.96626 / 230426853).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 38.5, Dec = -82.4 (J2000 degrees, equivalent to J2000 02h 34m, -82d 24'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 49.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_skymap_all_bn230426853.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_healpix_all_bn230426853.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230426853/quicklook/glg_lc_medres34_bn230426853.gif
GCN Circular #33686
P K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the ML pipeline (Abraham et al., 2021, MNRAS, 504, 3084) and the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a bright long GRB 230426A which was also detected by Fermi (Fermi GBM Team, GCN Circ. 33684).
The source was clearly detected in the 20-200 keV energy range. The light curve peaks at 2023-04-26 20:29:23.50 UTC. The measured peak count rate associated with the burst is 1773 (+77, -81) counts/s above the background in the combined data of all quadrants, with a total of 14876 (+653, -615) counts. The local mean background count rate was 454 (+2, -3) counts/s. Using cumulative rates, we measure a T90 of 23 (+3, -2) s. In the preliminary analysis, we find 1069 Compton events associated with this event.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-04-26 20:29:23.50 UTC. The measured peak count rate associated with the burst is 1179 (+82, -77) counts/s above the background in the combined data of all quadrants, with a total of 8609 (+655, -665) counts. The local mean background count rate was 1491 (+4, -5) counts/s. We measure a T90 of 18 (+5, -2) s from the cumulative Veto light curve.
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb
GCN Circular #33689
J. Wood (NASA/MSFC) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 20:28:59.97 UT on 26 April 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230426A (trigger 704233744/230426853) which was also detected by AstroSat CZTI (P K. Navaneeth et al. 2023, GCN 33686).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 38.53, Dec = -82.40 (J2000 degrees, equivalent to J2000 2h 34m, -82d 24'), with a statistical uncertainty of 1.00 degrees. (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a mixture of two Gaussians, one with a radius of 1.8 degrees (52% contribution) and one with a radius of 4.1 degrees (47% contribution) [A. Goldstein et al. 2020, ApJ, 895, 1]).
The angle from the Fermi LAT boresight is 49 degrees.
The GBM light curve consists of multiple pulses with a duration (T90) of about 25.9 s (50-300 keV). The time-averaged spectrum from T0+8.2 to T0+35.8 s is best fit by a Band function with Epeak = 77 +/- 2 keV, alpha = -1.34 +/- 0.02, and beta = -2.38 +/- 0.03.
The event fluence (10-1000 keV) in this time interval is (5.21 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+23 s in the 10-1000 keV band is 66.6 +/- 0.7 ph/s/cm^2.
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 #33691
FROM: Vladimir Lipunov at Moscow State U/Krylov Obs
V.Lipunov (Lomonosov MSU), D.A.H.Buckley (SAAO), Ya.Kechin, A.Chasovnikov, A.Kuznetsov, N.Tiurina, P.Balanutsa, O.Gress, E.Gorbovskoy, G.Antipov, K.Zhirkov, D.Vlasenko, V.Senik, V.Topolev, Yu.Tselik, Siyu Wu (Lomonosov Moscow State University, SAI, Physics Department), C.Francile, F. Podesta, C.Lopez, R. Podesta (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), N.M.Budnev, O.Ershova (ISU,API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University), K.Vetrov, V.Shumkov, T.Pogrosheva
MASTER-SAAO robotic telescope (Global MASTER Net http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, v.2010, 30L) located in South African Astronomical Observatory started (Lipunov et al. GCN 33685) inspect of the FERMI GRB230426.85 (trigger 704233744, Wood et al. GCN 33689, Ttrigger 20:28:59.97UT) errorbox 4359 sec after notice time (4391 sec after trigger time) at 2023-04-26 21:42:11UT with upper limit up to 19.5m, see our cover map https://master.sai.msu.ru/site/master2/observ.php?id=3D2212931
MASTER OT J023135.16-792104.8 - optical counterpart of GRB 230426A discovery 2023gwu
MASTER-SAAO auto-detection system found optical counterpart of GRB 230426.85 at R.A.,Dec(2000) =3D 02h 31m 35.16s , -79d 21m 04s.8 with unfiltered m_OT=3D17.4 at 2023-04-26 21:56:50UT and with optical decay at 10 images https://www.wis-tns.org/object/2023gwu .
There is no any sources in VIZIER database, no any objects in MPC at this time and no OT in MASTER database since Dec.2014. We used reference image on 2018-08-18.99148 UT with =C2=A0unfiltered mlim=3D20.6m.
Analysis will be continued.
Deep photometry and spectral observations are required.
The message may be cited.
GCN Circular #33702
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werne= r (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Obs= ervatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. = Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rez= enov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Researc= h 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. Gro= mes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration= .
The long duration GRB 230426A (Fermi/GBM detection: GCN 33684; Astrosat/CZT= I detection: GCN 33686; INTGERAL/SPI-ACS detection at 2023-04-26 20:29:23 U= T) 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 2023-04-26 20:29:21 UTC. Th= e T90 duration measured by VZLUSAT-2 is 35 s (25 s) and the significance du= ring T90 reaches 18 sigma (68 sigma) for detector unit no. 0 (no. 1).
The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB230426A_GCN_VZLUSAT2.pdf
All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/h= ea/VZLUSAT-2/ The GRB detectors on VZLUSAT-2 are a demonstration payload for a future Cub= eSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLU= SAT-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: 28-Apr-2023 [Disclaimer]