Gamma-ray Burst 231205A

(All information courtesy of the instrument teams.)

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Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 05 Dec 23 02:25:40 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      48
TRIGGER_NUM:     723435916
GRB_RA:          206.317d {+13h 45m 16s} (J2000),
                 206.591d {+13h 46m 22s} (current),
                 205.742d {+13h 42m 58s} (1950)
GRB_DEC:         +28.317d {+28d 19' 00"} (J2000),
                 +28.197d {+28d 11' 51"} (current),
                 +28.567d {+28d 34' 01"} (1950)
GRB_ERROR:       4.70 [deg radius, statistical plus systematic]
GRB_INTEN:       1431 [cnts/sec]
DATA_SIGNIF:     33.50 [sigma]
INTEG_TIME:      0.256 [sec]
GRB_DATE:        20283 TJD;   339 DOY;   23/12/05
GRB_TIME:        8711.41 SOD {02:25:11.41} UT
GRB_PHI:         292.00 [deg]
GRB_THETA:        75.00 [deg]
DATA_TIME_SCALE: 0.2560 [sec]
HARD_RATIO:      0.39
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       0,0,0, 1,1,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       251.22d {+16h 44m 53s}  -22.31d {-22d 18' 47"}
SUN_DIST:         66.37 [deg]   Sun_angle= 3.0 [hr] (West of Sun)
MOON_POSTN:      163.97d {+10h 55m 54s}  +10.59d {+10d 35' 34"}
MOON_DIST:        43.58 [deg]
MOON_ILLUM:      52 [%]
GAL_COORDS:       41.74, 78.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      192.12, 36.19 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231205101/quicklook/glg_lc_medres34_bn231205101.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 167.30,4.65 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 05 Dec 23 02:25:58 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      59
TRIGGER_NUM:     723435916
GRB_RA:          206.760d {+13h 47m 02s} (J2000),
                 207.044d {+13h 48m 11s} (current),
                 206.167d {+13h 44m 40s} (1950)
GRB_DEC:         +20.640d {+20d 38' 24"} (J2000),
                 +20.521d {+20d 31' 16"} (current),
                 +20.889d {+20d 53' 21"} (1950)
GRB_ERROR:       3.00 [deg radius, statistical only]
DATA_SIGNIF:     35.30 [sigma]
DATA_INTERVAL:   0.256 [sec]
GRB_DATE:        20283 TJD;   339 DOY;   23/12/05
GRB_TIME:        8711.41 SOD {02:25:11.41} UT
GRB_PHI:         298.00 [deg]
GRB_THETA:        80.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       251.22d {+16h 44m 53s}  -22.31d {-22d 18' 47"}
SUN_DIST:         60.77 [deg]   Sun_angle= 2.9 [hr] (West of Sun)
MOON_POSTN:      163.98d {+10h 55m 54s}  +10.59d {+10d 35' 30"}
MOON_DIST:        42.53 [deg]
MOON_ILLUM:      52 [%]
GAL_COORDS:        8.85, 75.74 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      196.43, 29.41 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231205101/quicklook/glg_lc_medres34_bn231205101.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_723435916.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        Bright hard burst in the GBM.  
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:     Tue 05 Dec 23 02:34:30 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     723435916
GRB_RA:          206.060d {+13h 44m 14s} (J2000),
                 206.342d {+13h 45m 22s} (current),
                 205.471d {+13h 41m 53s} (1950)
GRB_DEC:         +22.750d {+22d 45' 00"} (J2000),
                 +22.630d {+22d 37' 50"} (current),
                 +23.001d {+23d 00' 03"} (1950)
GRB_ERROR:       3.07 [deg radius, statistical only]
GRB_DATE:        20283 TJD;   339 DOY;   23/12/05
GRB_TIME:        8711.41 SOD {02:25:11.41} UT
GRB_PHI:         296.00 [deg]
GRB_THETA:        79.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       251.23d {+16h 44m 55s}  -22.31d {-22d 18' 49"}
SUN_DIST:         62.69 [deg]   Sun_angle= 3.0 [hr] (West of Sun)
MOON_POSTN:      164.04d {+10h 56m 09s}  +10.56d {+10d 33' 38"}
MOON_DIST:        42.13 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:       15.72, 77.26 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      194.73, 31.06 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231205101/quicklook/glg_lc_medres34_bn231205101.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231205101/quicklook/glg_locplot_all_bn231205101.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:        Bright hard burst in the GBM.  
COMMENTS:        This is likely a Short GRB.

GCN Circular #35263
The Fermi GBM team reports the detection of a likely SHORT GRB
At 02:25:11 UT on 5 Dec 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231205A (trigger 723435916.407408 / 231205101).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 206.1, Dec = 22.8 (J2000 degrees, equivalent to J2000 13h 44m, 22d 48'), with a statistical uncertainty of 3.1 degrees.
The angle from the Fermi LAT boresight is 79.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231205101/quicklook/glg_skymap_all_bn231205101.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/bn231205101/quicklook/glg_healpix_all_bn231205101.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231205101/quicklook/glg_lc_medres34_bn231205101.gif

GCN Circular #35265
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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB231205.10 (trigger No 723435916,13h 44m 14.40s , +22d 45m 00.0s, R=3.07) errorbox 35 sec after notice time and 81 sec after trigger time at 2023-12-05 02:26:33 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 56 deg. The sun altitude is -27.0 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB231205.10 errorbox 94 sec after notice time and 140 sec after trigger time at 2023-12-05 02:27:32 UT, with upper limit up to 19.4 mag. The observations began at zenith distance = 50 deg. The sun altitude is -20.9 deg.
The galactic latitude b = 77 deg., longitude l = 16 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2324126
We obtain a following upper limits.

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

      92 | 2023-12-05 02:26:33 |      MASTER-Tavrida | (13h 44m 11.74s , +20d 55m 58.7s) |   C |    20 | 17.5 |        
     118 | 2023-12-05 02:26:59 |      MASTER-Tavrida | (13h 44m 08.48s , +20d 57m 46.7s) |   C |    20 | 17.8 |        
     150 | 2023-12-05 02:27:26 |      MASTER-Tavrida | (13h 44m 08.48s , +20d 56m 05.9s) |   C |    30 | 18.0 |        
     156 | 2023-12-05 02:27:32 |   MASTER-Kislovodsk | (13h 46m 05.07s , +20d 45m 36.4s) |   C |    30 | 17.3 |        
     201 | 2023-12-05 02:27:32 |   MASTER-Kislovodsk | (13h 46m 05.07s , +20d 45m 36.4s) |   C |   120 | 18.3 |  Coadd 
     156 | 2023-12-05 02:27:32 |   MASTER-Kislovodsk | (13h 50m 29.92s , +20d 22m 37.7s) |   C |    30 | 17.9 |        
     201 | 2023-12-05 02:27:32 |   MASTER-Kislovodsk | (13h 50m 29.91s , +20d 22m 37.7s) |   C |   120 | 18.9 |  Coadd 
     187 | 2023-12-05 02:28:02 |      MASTER-Tavrida | (13h 44m 11.33s , +20d 57m 34.1s) |   C |    30 | 18.0 |        
     211 | 2023-12-05 02:28:22 |   MASTER-Kislovodsk | (13h 46m 09.73s , +20d 45m 58.2s) |   C |    40 | 17.4 |        
     211 | 2023-12-05 02:28:22 |   MASTER-Kislovodsk | (13h 50m 34.68s , +20d 22m 57.9s) |   C |    40 | 18.0 |        
     229 | 2023-12-05 02:28:40 |      MASTER-Tavrida | (13h 44m 05.57s , +20d 56m 54.6s) |   C |    40 | 18.3 |        
     276 | 2023-12-05 02:29:22 |   MASTER-Kislovodsk | (13h 46m 07.89s , +20d 47m 15.7s) |   C |    50 | 17.7 |        
     276 | 2023-12-05 02:29:22 |   MASTER-Kislovodsk | (13h 50m 33.01s , +20d 24m 14.6s) |   C |    50 | 18.1 |        
     281 | 2023-12-05 02:29:27 |      MASTER-Tavrida | (13h 44m 05.18s , +20d 57m 54.1s) |   C |    50 | 18.1 |        
     346 | 2023-12-05 02:30:27 |      MASTER-Tavrida | (13h 44m 10.23s , +20d 56m 52.7s) |   C |    60 | 18.3 |        
     351 | 2023-12-05 02:30:32 |   MASTER-Kislovodsk | (13h 46m 07.82s , +20d 45m 43.5s) |   C |    60 | 18.0 |        
     351 | 2023-12-05 02:30:32 |   MASTER-Kislovodsk | (13h 50m 33.08s , +20d 22m 42.4s) |   C |    60 | 18.3 |        
     566 | 2023-12-05 02:34:06 |      MASTER-Tavrida | (13h 40m 30.06s , +26d 12m 33.8s) |   C |    60 | 18.5 |        
     639 | 2023-12-05 02:34:50 |   MASTER-Kislovodsk | (13h 47m 54.37s , +22d 30m 13.6s) |   C |   120 | 19.1 |        
     639 | 2023-12-05 02:34:50 |   MASTER-Kislovodsk | (13h 43m 23.72s , +22d 53m 26.5s) |   C |   120 | 18.6 |        
     668 | 2023-12-05 02:35:19 |      MASTER-Tavrida | (13h 41m 15.13s , +23d 04m 31.8s) |   C |   120 | 18.7 |        
     789 | 2023-12-05 02:37:10 |   MASTER-Kislovodsk | (13h 43m 17.58s , +22d 52m 29.1s) |   C |   140 | 18.5 |        
     789 | 2023-12-05 02:37:10 |   MASTER-Kislovodsk | (13h 47m 48.38s , +22d 29m 16.7s) |   C |   140 | 18.9 |        
     812 | 2023-12-05 02:37:28 |      MASTER-Tavrida | (13h 41m 22.64s , +23d 03m 32.4s) |   C |   150 | 18.7 |        
     985 | 2023-12-05 02:40:06 |      MASTER-Tavrida | (13h 41m 14.64s , +23d 02m 33.6s) |   C |   180 | 18.9 |        
    1174 | 2023-12-05 02:43:15 |      MASTER-Tavrida | (13h 41m 21.41s , +23d 02m 39.5s) |   C |   180 | 18.9 |        
    1924 | 2023-12-05 02:55:45 |   MASTER-Kislovodsk | (13h 35m 12.26s , +26d 33m 16.6s) |   C |   180 | 19.4 |        
    2065 | 2023-12-05 02:59:05 |   MASTER-Kislovodsk | (13h 39m 21.80s , +22d 14m 27.0s) |   C |    60 | 18.2 |        
    2065 | 2023-12-05 02:59:05 |   MASTER-Kislovodsk | (13h 43m 55.57s , +21d 51m 18.1s) |   C |    60 | 18.9 |        
    2145 | 2023-12-05 03:00:26 |   MASTER-Kislovodsk | (13h 40m 03.37s , +22d 14m 25.8s) |   C |    60 | 12.3 |        
    2256 | 2023-12-05 03:02:17 |      MASTER-Tavrida | (13h 40m 29.46s , +26d 13m 03.5s) |   C |    60 | 18.5 |        
    2305 | 2023-12-05 03:03:06 |   MASTER-Kislovodsk | (13h 45m 04.66s , +20d 21m 40.4s) |   C |    60 | 18.3 |        
    2305 | 2023-12-05 03:03:06 |   MASTER-Kislovodsk | (13h 49m 34.53s , +19d 58m 27.8s) |   C |    60 | 18.7 |        
    2328 | 2023-12-05 03:03:29 |      MASTER-Tavrida | (13h 49m 23.21s , +26d 13m 51.0s) |   C |    60 | 18.4 |        
    2386 | 2023-12-05 03:04:27 |   MASTER-Kislovodsk | (13h 55m 39.83s , +22d 14m 52.7s) |   C |    60 | 17.9 |        
    2386 | 2023-12-05 03:04:27 |   MASTER-Kislovodsk | (14h 00m 12.79s , +21d 51m 38.8s) |   C |    60 | 18.5 |        
    2466 | 2023-12-05 03:05:47 |   MASTER-Kislovodsk | (13h 30m 05.97s , +26d 04m 28.1s) |   C |    60 | 18.2 |        
    2466 | 2023-12-05 03:05:47 |   MASTER-Kislovodsk | (13h 34m 49.41s , +25d 41m 30.3s) |   C |    60 | 18.9 |        
    2546 | 2023-12-05 03:07:07 |   MASTER-Kislovodsk | (13h 28m 51.97s , +20d 21m 34.3s) |   C |    60 | 17.9 |        
    2546 | 2023-12-05 03:07:07 |   MASTER-Kislovodsk | (13h 33m 23.18s , +19d 58m 27.7s) |   C |    60 | 18.8 |        
    2558 | 2023-12-05 03:07:19 |      MASTER-Tavrida | (13h 45m 24.11s , +18d 37m 21.3s) |   C |    60 | 18.4 |        
    2808 | 2023-12-05 03:11:29 |   MASTER-Kislovodsk | (13h 35m 30.39s , +18d 28m 30.9s) |   C |    60 | 17.6 |        
    2808 | 2023-12-05 03:11:29 |   MASTER-Kislovodsk | (13h 39m 57.89s , +18d 05m 20.6s) |   C |    60 | 18.2 |        
    2888 | 2023-12-05 03:12:49 |   MASTER-Kislovodsk | (13h 22m 53.75s , +22d 14m 43.3s) |   C |    60 | 17.8 |        
    2888 | 2023-12-05 03:12:49 |   MASTER-Kislovodsk | (13h 27m 28.81s , +21d 51m 42.7s) |   C |    60 | 18.3 |        
    3029 | 2023-12-05 03:14:10 |   MASTER-Kislovodsk | (13h 35m 16.88s , +26d 35m 10.2s) |   C |   180 | 18.9 |        
    3216 | 2023-12-05 03:18:17 |      MASTER-Tavrida | (13h 40m 31.87s , +26d 12m 15.3s) |   C |    60 | 18.7 |        
    3250 | 2023-12-05 03:18:51 |   MASTER-Kislovodsk | (13h 50m 56.33s , +24d 10m 13.1s) |   C |    60 | 17.7 |        
    3250 | 2023-12-05 03:18:51 |   MASTER-Kislovodsk | (13h 55m 33.54s , +23d 47m 08.4s) |   C |    60 | 18.2 |        
    3288 | 2023-12-05 03:19:29 |      MASTER-Tavrida | (13h 49m 29.84s , +26d 13m 32.0s) |   C |    60 | 18.6 |        
    3330 | 2023-12-05 03:20:11 |   MASTER-Kislovodsk | (13h 34m 24.34s , +24d 09m 36.2s) |   C |    60 | 17.9 |        
    3330 | 2023-12-05 03:20:11 |   MASTER-Kislovodsk | (13h 39m 02.60s , +23d 46m 37.1s) |   C |    60 | 18.3 |        
    3360 | 2023-12-05 03:20:40 |      MASTER-Tavrida | (13h 57m 24.39s , +26d 13m 48.1s) |   C |    60 | 18.5 |        
    3410 | 2023-12-05 03:21:31 |   MASTER-Kislovodsk | (13h 44m 59.67s , +20d 20m 28.1s) |   C |    60 | 17.6 |        
    3410 | 2023-12-05 03:21:31 |   MASTER-Kislovodsk | (13h 49m 29.50s , +19d 57m 19.7s) |   C |    60 | 17.7 |        
    3490 | 2023-12-05 03:22:51 |   MASTER-Kislovodsk | (13h 55m 46.27s , +22d 14m 28.3s) |   C |    60 | 17.2 |        
    3490 | 2023-12-05 03:22:51 |   MASTER-Kislovodsk | (14h 00m 19.16s , +21d 51m 18.4s) |   C |    60 | 17.6 |        
    3517 | 2023-12-05 03:23:18 |      MASTER-Tavrida | (13h 45m 20.59s , +18d 35m 49.4s) |   C |    60 | 18.5 |        
    3590 | 2023-12-05 03:24:31 |      MASTER-Tavrida | (13h 53m 53.04s , +18d 36m 05.3s) |   C |    60 | 18.0 |        
    3731 | 2023-12-05 03:26:52 |   MASTER-Kislovodsk | (14h 01m 18.20s , +20d 21m 47.0s) |   C |    60 | 16.8 |        
    3747 | 2023-12-05 03:27:08 |      MASTER-Tavrida | (14h 01m 17.13s , +24d 19m 11.7s) |   C |    60 | 18.5 |        
    3811 | 2023-12-05 03:28:12 |   MASTER-Kislovodsk | (13h 35m 26.87s , +18d 27m 52.6s) |   C |    60 | 17.1 |        
    3811 | 2023-12-05 03:28:12 |   MASTER-Kislovodsk | (13h 39m 54.52s , +18d 04m 44.0s) |   C |    60 | 17.7 |        
    3891 | 2023-12-05 03:29:32 |   MASTER-Kislovodsk | (13h 22m 50.41s , +22d 17m 03.3s) |   C |    60 | 17.2 |        
    3891 | 2023-12-05 03:29:32 |   MASTER-Kislovodsk | (13h 27m 26.03s , +21d 54m 06.4s) |   C |    60 | 17.6 |        
    4200 | 2023-12-05 03:34:41 |      MASTER-Tavrida | (13h 49m 29.04s , +26d 13m 37.3s) |   C |    60 | 18.5 |        
    4272 | 2023-12-05 03:35:53 |      MASTER-Tavrida | (13h 57m 23.60s , +26d 12m 33.5s) |   C |    60 | 18.4 |        
    4419 | 2023-12-05 03:38:20 |      MASTER-Tavrida | (13h 45m 26.74s , +18d 36m 49.4s) |   C |    60 | 18.7 |        
    4491 | 2023-12-05 03:39:32 |      MASTER-Tavrida | (13h 53m 46.25s , +18d 35m 39.3s) |   C |    60 | 18.2 |        
    4565 | 2023-12-05 03:40:46 |      MASTER-Tavrida | (14h 05m 50.91s , +22d 25m 22.0s) |   C |    60 | 18.2 |        
    4711 | 2023-12-05 03:43:12 |      MASTER-Tavrida | (14h 01m 11.89s , +24d 18m 29.4s) |   C |    60 | 18.3 |

Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
View this GCN Circular online at https://gcn.nasa.gov/circulars/35265.

GCN Circular #35266
GRB 231205A: GECAM-B detection of a short burst
Wenjun Tan, Shaolin Xiong, report on behalf of the GECAM team:
GECAM-B was triggered in-flight by a short burst, GRB 231205A at 2023-12-05T02:25:11.450 UTC(T0), which was also observed by Fermi/GBM (Fermi/GBM team, GCN 35263).
According to the realtime alert data of GECAM-B, this burst consists of one bright short pulse followed by weaker emission with a total duration (T90) of about ~0.3 sec (30-1020 keV).
Using the automatic on-ground localization pipeline with the realtime alert data, GECAM-B localized this burst to the following position (J2000):
```
Ra: 202.8 deg 
Dec: 26.8 deg
Err: 6.1 deg (1-sigma, statistical only)
```
GECAM location is consistent with that of Fermi/GBM within the error.
The time-averaged spectrum of GECAM-B realtime data from about T0-0.05 s to T0 could be adequately fit by a cut-off power-law with a fluence about 1.10E-6 erg/cm^2 in 20-1000 keV.
We note that these results are based on realtime alert data and thus very preliminary.
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).
GCN Circular #35268
Yanting Zhang, Shaolin Xiong, Yue Huang, Shuo Xiao, Xiaoyun Zhao, Ping Wang, report on behalf of the GECAM team:
The short burst, GRB 231205A, has been detected by GECAM-B (Tan et al., GCN 35266), Fermi/GBM (Fermi/GBM team, GCN 35263) and INTEGRAL/SPI-ACS. With the ETJASMIN pipeline (Energetic Transients joint analysis system for Multi-INstrument, Xiao et al., MNRAS, 514, 2397, 2022) and the realtime data of GECAM-B, INTEGRAL/SPI-ACS and Fermi/GBM, we did a low-latency joint location for this burst.
Firstly, we applied the Li-CCF method (Xiao et al., ApJ, 920, 43, 2021) to the realtime high temporal resolution (~1 ms) light curve of GECAM-B and the low-latency public 50 ms light curve of INTEGRAL/SPI-ACS, and derived the triangulation location as the following annuli:
```
--------------------------------------------------------------------------------------------------
Annulus                 Ra (deg)      Dec (deg)     Radius (deg)      Radius-Error (deg, 3sigma)
GECAM-B + SPI-ACS       209.519       59.889        40.961            1.272
--------------------------------------------------------------------------------------------------
```
Then, we combined this annulus location, the stand-alone locations provided by GECAM-B (Tan et al., GCN 35266) and Fermi/GBM (Fermi/GBM team, GCN 35263), as well as the Earth occultation of these instruments, and derived a refined location, which is much smaller than stand-alone ones.
This refined location (~3 sigma region) could be approximately described by a polygon region, whose center and corners are:
```
--------------------------------------
            Ra (deg)      Dec (deg)
Center      205.313	  19.155   
Corner1     215.859       19.155
Corner2     209.883       18.724
Corner3     202.148       18.871
Corner4     194.766       20.427
Corner5     205.313       19.524
--------------------------------------
```
For this refined location, the sky map and probability data could be found at: Sky map: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/GRB231205A-jointLoc-skymap-v01.png Data file: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/GRB231205A-jointLoc-healpix-v01.fits
ETJASMIN is developed for joint observation of high energy transients by the GECAM team. We acknowledge the public data of Fermi/GBM and INTEGRAL/SPI-ACS.
GCN Circular #35277
Oc=C3=A9lotl Lopez (UNAM), Alan M. Watson (UNAM), Rosa L. Becerra (UNAM), Margarita Pereyra (UNAM), Nat Butler (ASU), Simone Dichiara (Penn state university), Diego Gonzalez (UNAM), William H. Lee (UNAM), Alexander Kutyrev (GSFC/UMD), Srihari Ravi (ASU) and Eleonora Troja (Tor Vergara Roma) report:
We observed the field of the Fermi GBM GRB 231205A (Fermi GBM Team, GCN Circ. 35263) with the DDOTI wide-field imager at the Observatorio Astron=C3=B3mico Nacional on Sierra San Pedro M=C3=A1rtir ( http://ddoti.astroscu.unam.mx) from 2023-12-05 12:55:13 to 13:10:57 UTC (10.50 to 11.75 hours after the trigger).
We observed a region of 7 degrees in RA by 7 degrees in declination centered on the Fermi GBM Final Position of RA =3D 206.1 and Dec =3D 22.8 (J2000 degrees). This region contains 1 instrumental field or about 49 square degrees. We obtained 13.6 minutes of exposure per instrumental field in the w filter. We obtained AB photometry by calibration against the APASS catalog.
We detect no likely candidates for the afterglow to our 10-sigma upper limits of w =3D 18.89-19.41 (inter-quartile).
We thank the staff of the Observatorio Astron=C3=B3mico Nacional on San Pedro M=C3=A1rtir.
GCN Circular #35304
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.-L. Xiong, Y. Huang, X.-Y. Zhao, and P. Wang on behalf of the GECAM 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 bright, short-duration GRB 231205A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 35263; GECAM-B detection: Tan et al., GCN Circ. 35266; ETJASMIN localization: Zhang et al., GCN Circ. 35268) has been detected by Fermi-GBM (trigger 723435916), Konus-Wind, INTEGRAL (SPI-ACS), GECAM-B (GRD), and Mars-Odyssey (HEND) so far, at about 8711 s UT (02:25:11).
We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:
```
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  202.936 (13h 31m 45s) +17.932 (+17d 55' 55")
 Corners:
  203.258 (13h 33m 02s) +18.299 (+18d 17' 58")
  202.683 (13h 30m 44s) +17.694 (+17d 41' 38")
  202.612 (13h 30m 27s) +17.557 (+17d 33' 25")
  203.188 (13h 32m 45s) +18.166 (+18d 09' 57")
 ---------------------------------------------
```
The error box area is 119 sq. arcmin, and its maximum dimension is 58 arcmin (the minimum one is 2.4 arcmin). The Sun distance was 62 deg.
This localization may be improved.
The IPN localization is consistent with, but reduces the area of, the Fermi-GBM final localization and ETJASMIN localization.
A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB231205_T08710/IPN
The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
GCN Circular #35402
Chenyu Wang, Zirui Yang, Longhao Li and Songyu Shen report on behalf of the GRID Collaboration:
GRID-07 reports the detection of the short-duration GRB 231205A, which was also detected by Fermi/GBM and GECAM-B(GCN Circular 35263, 35266).
The event was triggered with GRID on 2023-12-05 at 02:25:11.2 UTC. The meas= ured burst duration (T90) in the 30-2000 keV range is approximately 0.4 =C2= =B1 0.1 seconds.
The GRID light curve of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB231205A/GRID_231205A_ltcv.pdf.
GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to the following references: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4.

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Jochen Greiner, last update: 19-Dec-2023 [Disclaimer]