Gamma-ray Burst 211204C

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 Dec 21 21:37:27 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     660346625
GRB_RA:          353.083d {+23h 32m 20s} (J2000),
                 353.342d {+23h 33m 22s} (current),
                 352.497d {+23h 29m 59s} (1950)
GRB_DEC:         +57.267d {+57d 16' 00"} (J2000),
                 +57.388d {+57d 23' 16"} (current),
                 +56.990d {+56d 59' 26"} (1950)
GRB_ERROR:       15.57 [deg radius, statistical plus systematic]
GRB_INTEN:       80 [cnts/sec]
DATA_SIGNIF:     7.00 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        19552 TJD;   338 DOY;   21/12/04
GRB_TIME:        77820.55 SOD {21:37:00.55} UT
GRB_PHI:         330.00 [deg]
GRB_THETA:       150.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.34
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      88%  GRB
2nd_MOST_LIKELY:   7%  Cyg X-1
DETECTORS:       0,1,0, 0,1,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       251.53d {+16h 46m 08s}  -22.35d {-22d 21' 00"}
SUN_DIST:        114.98 [deg]   Sun_angle= -6.8 [hr] (East of Sun)
MOON_POSTN:      260.15d {+17h 20m 37s}  -24.85d {-24d 50' 58"}
MOON_DIST:       112.41 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      112.36, -3.97 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       27.11, 52.91 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_lc_medres34_bn211204901.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 222.97,-12.73 [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 Dec 21 21:37:34 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     660346625
GRB_RA:          352.983d {+23h 31m 56s} (J2000),
                 353.241d {+23h 32m 58s} (current),
                 352.398d {+23h 29m 36s} (1950)
GRB_DEC:         +57.617d {+57d 37' 00"} (J2000),
                 +57.738d {+57d 44' 16"} (current),
                 +57.341d {+57d 20' 26"} (1950)
GRB_ERROR:       5.62 [deg radius, statistical plus systematic]
GRB_INTEN:       378 [cnts/sec]
DATA_SIGNIF:     26.30 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        19552 TJD;   338 DOY;   21/12/04
GRB_TIME:        77820.55 SOD {21:37:00.55} UT
GRB_PHI:         330.00 [deg]
GRB_THETA:       150.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.24
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   2%  Cyg X-1
DETECTORS:       0,1,0, 0,1,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       251.53d {+16h 46m 08s}  -22.35d {-22d 21' 00"}
SUN_DIST:        114.94 [deg]   Sun_angle= -6.8 [hr] (East of Sun)
MOON_POSTN:      260.15d {+17h 20m 37s}  -24.85d {-24d 50' 59"}
MOON_DIST:       112.42 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      112.42, -3.62 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       27.43, 53.21 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_lc_medres34_bn211204901.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 222.97,-12.73 [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 Dec 21 21:37:41 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     660346625
GRB_RA:          344.700d {+22h 58m 48s} (J2000),
                 344.940d {+22h 59m 46s} (current),
                 344.154d {+22h 56m 37s} (1950)
GRB_DEC:         +51.680d {+51d 40' 48"} (J2000),
                 +51.798d {+51d 47' 52"} (current),
                 +51.412d {+51d 24' 43"} (1950)
GRB_ERROR:       3.75 [deg radius, statistical only]
DATA_SIGNIF:     17.50 [sigma]
DATA_INTERVAL:   2.048 [sec]
GRB_DATE:        19552 TJD;   338 DOY;   21/12/04
GRB_TIME:        77820.55 SOD {21:37:00.55} UT
GRB_PHI:         325.00 [deg]
GRB_THETA:       143.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       251.53d {+16h 46m 08s}  -22.35d {-22d 21' 00"}
SUN_DIST:        109.44 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:      260.16d {+17h 20m 37s}  -24.85d {-24d 51' 00"}
MOON_DIST:       106.21 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      105.77, -7.40 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       15.15, 51.71 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_lc_medres34_bn211204901.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_660346625.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 Dec 21 21:38:18 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      0
TRIGGER_NUM:     660346625
GRB_RA:          345.860d {+23h 03m 26s} (J2000),
                 346.105d {+23h 04m 25s} (current),
                 345.303d {+23h 01m 13s} (1950)
GRB_DEC:         +50.520d {+50d 31' 12"} (J2000),
                 +50.638d {+50d 38' 18"} (current),
                 +50.250d {+50d 15' 01"} (1950)
GRB_ERROR:       3.69 [deg radius, statistical only]
DATA_SIGNIF:     17.70 [sigma]
DATA_INTERVAL:   6.144 [sec]
GRB_DATE:        19552 TJD;   338 DOY;   21/12/04
GRB_TIME:        77820.55 SOD {21:37:00.55} UT
GRB_PHI:         323.00 [deg]
GRB_THETA:       143.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       251.53d {+16h 46m 08s}  -22.35d {-22d 21' 00"}
SUN_DIST:        109.92 [deg]   Sun_angle= -6.3 [hr] (East of Sun)
MOON_POSTN:      260.16d {+17h 20m 39s}  -24.85d {-24d 51' 03"}
MOON_DIST:       106.51 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      105.95, -8.76 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       14.94, 50.35 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_lc_medres34_bn211204901.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_660346625.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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=9552).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 Dec 21 21:38:27 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      1
TRIGGER_NUM:     660346625
GRB_RA:          344.770d {+22h 59m 05s} (J2000),
                 345.011d {+23h 00m 03s} (current),
                 344.223d {+22h 56m 53s} (1950)
GRB_DEC:         +51.550d {+51d 32' 60"} (J2000),
                 +51.668d {+51d 40' 04"} (current),
                 +51.282d {+51d 16' 54"} (1950)
GRB_ERROR:       1.81 [deg radius, statistical only]
DATA_SIGNIF:     26.10 [sigma]
DATA_INTERVAL:   7.168 [sec]
GRB_DATE:        19552 TJD;   338 DOY;   21/12/04
GRB_TIME:        77820.55 SOD {21:37:00.55} UT
GRB_PHI:         325.00 [deg]
GRB_THETA:       143.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       251.53d {+16h 46m 08s}  -22.35d {-22d 21' 00"}
SUN_DIST:        109.46 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:      260.16d {+17h 20m 39s}  -24.85d {-24d 51' 04"}
MOON_DIST:       106.21 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      105.75, -7.54 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       15.08, 51.58 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_lc_medres34_bn211204901.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_660346625.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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=9552).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 Dec 21 21:38:36 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      3
TRIGGER_NUM:     660346625
GRB_RA:          343.600d {+22h 54m 24s} (J2000),
                 343.836d {+22h 55m 21s} (current),
                 343.064d {+22h 52m 15s} (1950)
GRB_DEC:         +52.710d {+52d 42' 36"} (J2000),
                 +52.827d {+52d 49' 38"} (current),
                 +52.443d {+52d 26' 36"} (1950)
GRB_ERROR:       1.18 [deg radius, statistical only]
DATA_SIGNIF:     53.70 [sigma]
DATA_INTERVAL:   12.288 [sec]
GRB_DATE:        19552 TJD;   338 DOY;   21/12/04
GRB_TIME:        77820.55 SOD {21:37:00.55} UT
GRB_PHI:         327.00 [deg]
GRB_THETA:       143.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       251.53d {+16h 46m 08s}  -22.35d {-22d 21' 00"}
SUN_DIST:        108.99 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:      260.17d {+17h 20m 40s}  -24.85d {-24d 51' 05"}
MOON_DIST:       105.93 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      105.60, -6.18 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       15.35, 52.94 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_lc_medres34_bn211204901.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_660346625.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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=9552).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 Dec 21 21:46:20 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     660346625
GRB_RA:          346.440d {+23h 05m 46s} (J2000),
                 346.679d {+23h 06m 43s} (current),
                 345.897d {+23h 03m 35s} (1950)
GRB_DEC:         +55.840d {+55d 50' 24"} (J2000),
                 +55.959d {+55d 57' 31"} (current),
                 +55.570d {+55d 34' 11"} (1950)
GRB_ERROR:       1.72 [deg radius, statistical only]
GRB_DATE:        19552 TJD;   338 DOY;   21/12/04
GRB_TIME:        77820.55 SOD {21:37:00.55} UT
GRB_PHI:         330.00 [deg]
GRB_THETA:       146.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       251.54d {+16h 46m 09s}  -22.35d {-22d 21' 03"}
SUN_DIST:        111.19 [deg]   Sun_angle= -6.3 [hr] (East of Sun)
MOON_POSTN:      260.26d {+17h 21m 01s}  -24.86d {-24d 51' 49"}
MOON_DIST:       108.47 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      108.43, -4.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       20.89, 54.25 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_lc_medres34_bn211204901.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_locplot_all_bn211204901.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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=9552).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 05 Dec 21 00:19:40 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     660346625
GRB_RA:          346.440d {+23h 05m 46s} (J2000),
                 346.679d {+23h 06m 43s} (current),
                 345.897d {+23h 03m 35s} (1950)
GRB_DEC:         +55.840d {+55d 50' 24"} (J2000),
                 +55.959d {+55d 57' 31"} (current),
                 +55.570d {+55d 34' 11"} (1950)
GRB_ERROR:       1.72 [deg radius, statistical only]
GRB_DATE:        19552 TJD;   338 DOY;   21/12/04
GRB_TIME:        77820.55 SOD {21:37:00.55} UT
GRB_PHI:         330.00 [deg]
GRB_THETA:       146.00 [deg]
E_RANGE:         50.000 - 300.000 [keV]
LOC_ALGORITHM:   300 (Gnd S/W Version number)
SUN_POSTN:       251.66d {+16h 46m 37s}  -22.36d {-22d 21' 52"}
SUN_DIST:        111.14 [deg]   Sun_angle= -6.3 [hr] (East of Sun)
MOON_POSTN:      262.02d {+17h 28m 06s}  -25.10d {-25d 05' 48"}
MOON_DIST:       107.71 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      108.43, -4.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       20.89, 54.25 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_lc_medres34_bn211204901.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_locplot_all_bn211204901.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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=9552).

GCN Circular #31171
The Fermi GBM team reports the detection of a likely LONG GRB
At 21:37:00 UT on 4 Dec 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 211204C (trigger 660346625.552088 / 211204901).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 346.4, Dec = 55.8 (J2000 degrees, equivalent to J2000 23h 05m, 55d 47'), with a statistical uncertainty of 1.7 degrees.
The angle from the Fermi LAT boresight is 146.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_skymap_all_bn211204901.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_healpix_all_bn211204901.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn211204901/quicklook/glg_lc_medres34_bn211204901.gif

GCN Circular #31172
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, T.Pogrosheva, E.Minkina, A.Chasovnikov, V.Topolev, V.Grinshpun, D.Kuvshinov, D. Cheryasov (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. Gres, N.M. Budnev (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational State University)
MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) started inspect of the Fermi GRB 211204C ( Fermi GBM team, GCN 31171) errorbox 113 sec after notice time and 142 sec after trigger time at 2021-12-04 21:39:22 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 36 deg. The sun altitude is -46.1 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 211204C errorbox 592 sec after notice time and 621 sec after trigger time at 2021-12-04 21:47:21 UT, with upper limit up to 13.2 mag. The observations began at zenith distance = 59 deg. The sun altitude is -67.2 deg.
The galactic latitude b = -4 deg., longitude l = 109 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1804120
We obtain a following upper limits.

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

     157 | 2021-12-04 21:39:22 |          MASTER-IAC | (23h 28m 59.46s , +57d 30m 33.7s) |  P| |    30 | 16.9 |        
     202 | 2021-12-04 21:39:22 |          MASTER-IAC | (23h 28m 59.46s , +57d 30m 33.7s) |  P| |   120 | 17.7 |  Coadd 
     212 | 2021-12-04 21:40:12 |          MASTER-IAC | (23h 28m 51.98s , +57d 29m 37.7s) |  P| |    40 | 17.2 |        
     277 | 2021-12-04 21:41:12 |          MASTER-IAC | (23h 28m 57.77s , +57d 29m 49.8s) |  P| |    50 | 17.3 |        
     352 | 2021-12-04 21:42:22 |          MASTER-IAC | (23h 28m 54.98s , +57d 31m 18.2s) |  P| |    60 | 17.4 |        
     641 | 2021-12-04 21:46:41 |          MASTER-IAC | (23h 02m 55.70s , +55d 44m 36.6s) |  P| |   120 | 17.7 |        
     641 | 2021-12-04 21:46:41 |          MASTER-IAC | (23h 04m 33.66s , +55d 38m 30.9s) |  P- |   120 | 16.5 |        
     681 | 2021-12-04 21:47:21 |   MASTER-Kislovodsk | (23h 05m 40.54s , +55d 45m 23.3s) |  P- |   120 | 12.3 |        
     846 | 2021-12-04 21:47:21 |   MASTER-Kislovodsk | (23h 05m 40.54s , +55d 45m 23.3s) |  P- |   450 | 12.3 |  Coadd 
     791 | 2021-12-04 21:49:01 |          MASTER-IAC | (23h 02m 50.22s , +55d 44m 07.7s) |  P| |   140 | 17.8 |        
     791 | 2021-12-04 21:49:01 |          MASTER-IAC | (23h 04m 28.38s , +55d 38m 01.6s) |  P- |   140 | 16.7 |        
     837 | 2021-12-04 21:49:42 |   MASTER-Kislovodsk | (23h 05m 37.26s , +55d 46m 40.5s) |  P- |   150 | 12.4 |        
     966 | 2021-12-04 21:51:41 |          MASTER-IAC | (23h 02m 49.52s , +55d 45m 09.1s) |  P| |   170 | 17.9 |        
     966 | 2021-12-04 21:51:41 |          MASTER-IAC | (23h 04m 27.93s , +55d 39m 02.5s) |  P- |   170 | 16.9 |        
    1022 | 2021-12-04 21:52:32 |   MASTER-Kislovodsk | (23h 05m 37.19s , +55d 45m 32.4s) |  P- |   180 | 13.2 |

The observation and reduction will continue. The message may be cited.

GCN Circular #31173
Y. Q. Zhang, S. L. Xiong, C. Cai, S. Xiao, P. Zhang, C. Y. Li, S. L. Xie, X. Y. Zhao, Y. Huang, X. Y. Song, J. C. Liu, Y. Zhao, Z. W. Guo, C. Zheng, W. C. Xue, C. W. Wang, Q. B. Yi, B. X. Zhang, W. X. Peng, R. Qiao, D. Y. Guo, X. B. Li, X. Ma, L. M. Song, P. Wang, J. Wang, Z. Zhang, S. J. Zheng, W. Chen, J. J. He, G. Y. Zhao, Y. Q. Du, H. Wu, J. Liang, Q. Luo, X. L. Zhang, H. M. Zhang, Z. H. An, M. Gao, K. Gong, B. Li, C. Li, J. H. Li, X. Q. Li, Y. G. Li, X. H. Liang, X. J. Liu, Y. Q. Liu, X. L. Sun, Y. L. Tuo, J. Z. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, X. Zhou, F. J. Lu, S. N. Zhang (IHEP) report on behalf of GECAM team:
During the commissioning phase, GECAM-B was triggered in-flight by a long burst, GRB 211204C, at 2021-12-04T21:37:00.250 UTC (denoted as T0), which was also observed by Fermi/GBM (GCN #31171) and INTEGRAL/SPI-ACS (TrigID #9552).
GECAM alert data was downlinked to the ground through the short message service of BeiDou Navigation Satellite System (BDS) within ~60 s after T0.
According to the BDS alert data, this burst mainly consists of a broad pulse with a duration of about 25 s.
The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_all_combine_92353020.png
Using the automatic on-ground localization pipeline with the BDS alert data, GECAM-B localized this burst to the following position (J2000):
```
Ra: 334.1 deg 
Dec: 55.1 deg
Err: 3.8 deg (1-sigma, statistical only)
```
The current systematic error of location is estimated to be several degrees which could be minimized by the ongoing calibration.
The GECAM preliminary location could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_skymap_bdm_92353020_V01.png
GECAM location is consistent with the Fermi/GBM position within the error.
Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog.
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS).
GCN Circular #31174
James DeLaunay (UAlabama), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), Jamie A. Kennea (PSU), report:
Swift/BAT did not successfully trigger on GRB 211204C (T0: 2021-12-04T21:37:00 UTC, Fermi/GBM GCN 31171, GECAM GCN 31173, INTEGRAL/SPI-ACS trig #9552).
The Fermi/GBM, INTEGRAL, and GECAM notices, 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, arXiv:2111.01769), detects the burst with a sqrt(TS) of 116.1 in a 8.192 s analysis time bin. Estimated T90 in the detector is 19.5 +/- 0.1 s (15-350 keV).
NITRATES strongly prefers an origin for the burst coming from outside the coded FOV, with DeltaLLHOut of -520. An out of FOV origin is consistent with the Fermi/GBM and GECAM localizations.
See Section 9.1 and Figure 20 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 #31177
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey teams,
K. Hurley, on behalf of the IPN,
A. Ridnaia, D. Frederiks, D. Svinkin, A. Lysenko, and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, 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, and R. Starr, on behalf of the GRS-Odyssey GRB team, report:
The long-duration GRB 211204C (Fermi GBM detection: Fermi GBM team, GCN 31171; GECAM detection: Zhang et al., GCN 31173; Swift/BAT-GUANO detection: DeLaunay et al., GCN 31174) was detected by Fermi (GBM trigger 660346625), Konus-Wind, INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), GECAM-B (GRD), and Swift (BAT) at about 77820 s UT (21:37:00). 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:
  338.952 (22h 35m 48s) +52.171 (+52d 10' 15")
 Corners:
  338.910 (22h 35m 38s) +49.891 (+49d 53' 29")
  338.806 (22h 35m 14s) +49.979 (+49d 58' 43")
  339.068 (22h 36m 16s) +54.400 (+54d 24' 01")
  339.176 (22h 36m 42s) +54.316 (+54d 18' 59")
 ---------------------------------------------
```
The error box area is 1084 sq. armin, and its maximum dimension is 4.5 deg (the minimum one is 4.1 arcmin). The Sun distance was 105 deg.
This box may be improved.
The IPN localization is consistent with, but reduces the area of, the Fermi GBM on-ground calculated localization (GCN Circ. 31171) and GECAM-B automatic on-ground localization (GCN Circ. 31173).
A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB211204_T77823/IPN
The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
GCN Circular #31178
V. Prasad (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (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 CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed detection of the long GRB 211204C, which was also detected by Fermi (GCN 31171), GECAM (Zhang et al., GCN 31173) and Swift/BAT-GUANO (DeLaunay et al., GCN 31174) with IPN triangulation reported (GCN 31177).
The source was clearly detected in the 20-200 keV energy range. The light curve peaks at 2021-12-04 21:37:06.50 UT. The measured peak count rate associated with the burst is 426 (+57, -23) cts/s above the background in the combined data of two quadrants, with a total of 3173 (+195, -220) cts. The local mean background count rate was 500 (+2, -2) cts/s. Using cumulative rates, we measure a T90 of 13 (+2, -1) s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2021-12-04 21:37:04.16 UT. The measured peak count rate is 592 (+80, -46) cts/s above the background in the combined Veto data of four quadrants, with a total of 4150 (+285, -354) cts. The local mean background count rate was 1677 (+4, -4) cts/s. We measure a T90 of 10 (+1, -1) s from the cumulative Veto light curve.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
GCN Circular #31186
Boyan A. Hristov (UAH) reports on behalf of the Fermi GBM Team:
At 21:37:00.55 UT on 04 December 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 211204C (trigger 660346625 / 211204901), which was also detected by GECAM-B (Zhang et al. 2021, GCN 31173), INTEGRAL SPI_ACS (trigger num. 9552), Swift/BAT-GUANO (Tohuvavohu et al., GCN 31174), AstroSat CZTI detection (Waratkar et al., GCN 31178) and was triangulated by IPN (Ridnaia et al., GCN 31177).
The GECAM localization and the IPN triangulation are consistent with the GBM localization (GCN 31171).
The GBM light curve consists of a single spike with a duration (T90) of about 17.41 s +/- 2.00 s (50-300 keV). The time-averaged spectrum from T0+0.003 s to T0+19.456 s is adequately fit by a Band function with Epeak = 287.90 +/- 34.30 keV, alpha = -0.71 +/- 0.09, and beta = -2.37 +/- 0.19.
The event fluence (10-1000 keV) in this time interval is (2.827 +/- 0.105)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+7.040 s in the 10-1000 keV band is 19.9063 +/- 1.1 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/

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Jochen Greiner, last update: 08-Dec-2021 [Disclaimer]