Gamma-ray Burst 241209D

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:00:03 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1273106,   Seg_Num: 0
GRB_RA:          190.111d {+12h 40m 27s} (J2000),
                 190.432d {+12h 41m 44s} (current),
                 189.468d {+12h 37m 52s} (1950)
GRB_DEC:          -2.879d {-02d 52' 42"} (J2000),
                  -3.015d {-03d 00' 54"} (current),
                  -2.604d {-02d 36' 14"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4380 [cnts]    Image_Peak=337 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       21226 [cnts]
BKG_TIME:        39573.31 SOD {10:59:33.31} UT
BKG_DUR:         8 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        39586.43 SOD {10:59:46.43} UT
GRB_PHI:          37.45 [deg]
GRB_THETA:        26.87 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     29.98 [sigma]
IMAGE_SIGNIF:    12.99 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +2  +0  +0 -38  +0 
SUN_POSTN:       256.81d {+17h 07m 15s}  -22.88d {-22d 52' 53"}
SUN_DIST:         67.10 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      358.84d {+23h 55m 22s}   -0.87d {-00d 51' 59"}
MOON_DIST:       167.78 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      297.46, 59.88 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      190.42,  1.36 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 10.34,-19.88 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(2.0<100sec) coincident with the FERMI_GBM event (trignum=755434789).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:00:13 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      48
TRIGGER_NUM:     755434789
GRB_RA:          198.033d {+13h 12m 08s} (J2000),
                 198.340d {+13h 13m 22s} (current),
                 197.419d {+13h 09m 41s} (1950)
GRB_DEC:         +16.950d {+16d 56' 60"} (J2000),
                 +16.818d {+16d 49' 05"} (current),
                 +17.215d {+17d 12' 55"} (1950)
GRB_ERROR:       13.33 [deg radius, statistical plus systematic]
GRB_INTEN:       147 [cnts/sec]
DATA_SIGNIF:     9.70 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        39584.09 SOD {10:59:44.09} UT
GRB_PHI:         290.00 [deg]
GRB_THETA:        60.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.51
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       0,0,0, 1,1,0, 0,1,0, 0,0,0, 0,0,
SUN_POSTN:       256.81d {+17h 07m 15s}  -22.88d {-22d 52' 53"}
SUN_DIST:         69.60 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:      358.84d {+23h 55m 23s}   -0.87d {-00d 51' 56"}
MOON_DIST:       155.04 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      329.18, 78.75 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      189.71, 22.66 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_lc_medres34_bn241209458.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 339.07,17.38 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the SWIFT_BAT event (trignum=1273106).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:00:22 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      59
TRIGGER_NUM:     755434789
GRB_RA:          188.600d {+12h 34m 24s} (J2000),
                 188.918d {+12h 35m 40s} (current),
                 187.963d {+12h 31m 51s} (1950)
GRB_DEC:          +4.883d {+04d 52' 60"} (J2000),
                  +4.746d {+04d 44' 46"} (current),
                  +5.159d {+05d 09' 32"} (1950)
GRB_ERROR:       8.18 [deg radius, statistical plus systematic]
GRB_INTEN:       212 [cnts/sec]
DATA_SIGNIF:     20.30 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        39584.09 SOD {10:59:44.09} UT
GRB_PHI:         287.00 [deg]
GRB_THETA:        75.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.48
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       0,0,0, 1,1,0, 0,1,0, 0,0,0, 0,0,
SUN_POSTN:       256.81d {+17h 07m 15s}  -22.88d {-22d 52' 53"}
SUN_DIST:         71.74 [deg]   Sun_angle= 4.5 [hr] (West of Sun)
MOON_POSTN:      358.85d {+23h 55m 23s}   -0.87d {-00d 51' 53"}
MOON_DIST:       169.22 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      291.84, 67.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      185.96,  7.90 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_lc_medres34_bn241209458.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 339.07,17.38 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the SWIFT_BAT event (trignum=1273106).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:00:32 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     755434789
GRB_RA:          189.870d {+12h 39m 29s} (J2000),
                 190.190d {+12h 40m 46s} (current),
                 189.229d {+12h 36m 55s} (1950)
GRB_DEC:          -1.330d {-01d 19' 47"} (J2000),
                  -1.467d {-01d 28' 00"} (current),
                  -1.055d {-01d 03' 19"} (1950)
GRB_ERROR:       3.06 [deg radius, statistical only]
DATA_SIGNIF:     24.40 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        39584.09 SOD {10:59:44.09} UT
GRB_PHI:         291.00 [deg]
GRB_THETA:        80.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       256.81d {+17h 07m 15s}  -22.88d {-22d 52' 53"}
SUN_DIST:         67.95 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      358.85d {+23h 55m 23s}   -0.86d {-00d 51' 50"}
MOON_DIST:       168.42 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      296.68, 61.40 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      189.59,  2.69 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_lc_medres34_bn241209458.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_755434789.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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the SWIFT_BAT event (trignum=1273106).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:01:28 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      2
TRIGGER_NUM:     755434789
GRB_RA:          191.190d {+12h 44m 46s} (J2000),
                 191.510d {+12h 46m 02s} (current),
                 190.549d {+12h 42m 12s} (1950)
GRB_DEC:          -0.870d {-00d 52' 11"} (J2000),
                  -1.006d {-01d 00' 21"} (current),
                  -0.597d {-00d 35' 47"} (1950)
GRB_ERROR:       1.60 [deg radius, statistical only]
DATA_SIGNIF:     34.60 [sigma]
DATA_INTERVAL:   9.216 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        39584.09 SOD {10:59:44.09} UT
GRB_PHI:         292.00 [deg]
GRB_THETA:        79.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       256.81d {+17h 07m 16s}  -22.88d {-22d 52' 53"}
SUN_DIST:         66.94 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      358.85d {+23h 55m 25s}   -0.86d {-00d 51' 35"}
MOON_DIST:       167.21 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      299.38, 61.96 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      190.63,  3.63 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_lc_medres34_bn241209458.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_755434789.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 SWIFT_BAT event (trignum=1273106).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:01:18 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      1
TRIGGER_NUM:     755434789
GRB_RA:          189.410d {+12h 37m 38s} (J2000),
                 189.730d {+12h 38m 55s} (current),
                 188.770d {+12h 35m 05s} (1950)
GRB_DEC:          -0.030d {-00d 01' 47"} (J2000),
                  -0.167d {-00d 10' 00"} (current),
                  +0.245d {+00d 14' 42"} (1950)
GRB_ERROR:       1.82 [deg radius, statistical only]
DATA_SIGNIF:     24.90 [sigma]
DATA_INTERVAL:   6.144 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        39584.09 SOD {10:59:44.09} UT
GRB_PHI:         290.00 [deg]
GRB_THETA:        79.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       256.81d {+17h 07m 16s}  -22.88d {-22d 52' 53"}
SUN_DIST:         68.91 [deg]   Sun_angle= 4.5 [hr] (West of Sun)
MOON_POSTN:      358.85d {+23h 55m 25s}   -0.86d {-00d 51' 37"}
MOON_DIST:       169.08 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      295.41, 62.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      188.66,  3.70 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_lc_medres34_bn241209458.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_755434789.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 SWIFT_BAT event (trignum=1273106).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:01:53 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      4
TRIGGER_NUM:     755434789
GRB_RA:          190.810d {+12h 43m 14s} (J2000),
                 191.130d {+12h 44m 31s} (current),
                 190.168d {+12h 40m 40s} (1950)
GRB_DEC:          -1.690d {-01d 41' 23"} (J2000),
                  -1.826d {-01d 49' 34"} (current),
                  -1.416d {-01d 24' 57"} (1950)
GRB_ERROR:       1.40 [deg radius, statistical only]
DATA_SIGNIF:     40.30 [sigma]
DATA_INTERVAL:   19.456 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        39584.09 SOD {10:59:44.09} UT
GRB_PHI:         292.00 [deg]
GRB_THETA:        80.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       256.82d {+17h 07m 16s}  -22.88d {-22d 52' 54"}
SUN_DIST:         66.95 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      358.86d {+23h 55m 26s}   -0.86d {-00d 51' 28"}
MOON_DIST:       167.44 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      298.69, 61.11 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      190.60,  2.72 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_lc_medres34_bn241209458.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_755434789.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 SWIFT_BAT event (trignum=1273106).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:09:04 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     755434789
GRB_RA:          191.670d {+12h 46m 41s} (J2000),
                 191.991d {+12h 47m 58s} (current),
                 191.028d {+12h 44m 07s} (1950)
GRB_DEC:          -2.160d {-02d 09' 35"} (J2000),
                  -2.296d {-02d 17' 44"} (current),
                  -1.887d {-01d 53' 12"} (1950)
GRB_ERROR:       1.89 [deg radius, statistical only]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        39584.09 SOD {10:59:44.09} UT
GRB_PHI:         293.00 [deg]
GRB_THETA:        80.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       256.82d {+17h 07m 17s}  -22.88d {-22d 52' 55"}
SUN_DIST:         65.98 [deg]   Sun_angle= 4.3 [hr] (West of Sun)
MOON_POSTN:      358.92d {+23h 55m 41s}   -0.82d {-00d 49' 25"}
MOON_DIST:       166.57 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      300.50, 60.69 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      191.58,  2.63 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_lc_medres34_bn241209458.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_locplot_all_bn241209458.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 SWIFT_BAT event (trignum=1273106).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:02:09 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     1273106,   Seg_Num: 0
GRB_RA:          190.1137d {+12h 40m 27.2s} (J2000),
                 190.4345d {+12h 41m 44.2s} (current),
                 189.4709d {+12h 37m 53.0s} (1950)
GRB_DEC:          -2.8901d {-02d 53' 24.3"} (J2000),
                  -3.0267d {-03d 01' 36.1"} (current),
                  -2.6158d {-02d 36' 56.7"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       101 [cnts]
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  39680.00 SOD {11:01:20.00} UT,   93.6 [sec] since BAT Trigger Time
CENTROID_X:      286.74,  raw= 287  [pixels]
CENTROID_Y:      296.65,  raw= 297  [pixels]
ROLL:            113.61 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -4.81
GRB_POS_XRT_Z:   -58.59
IMAGE_URL:       sw01273106000msxps_rw.img
SUN_POSTN:       256.82d {+17h 07m 16s}  -22.88d {-22d 52' 54"}
SUN_DIST:         67.10 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      358.86d {+23h 55m 27s}   -0.86d {-00d 51' 23"}
MOON_DIST:       167.80 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      297.46, 59.86 [deg] galactic lon,lat of the burst
ECL_COORDS:      190.43,  1.35 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:02:12 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     1273106,   Seg_Num: 0
GRB_RA:          190.1137d {+12h 40m 27.2s} (J2000),
                 190.4345d {+12h 41m 44.2s} (current),
                 189.4709d {+12h 37m 53.0s} (1950)
GRB_DEC:          -2.8901d {-02d 53' 24.3"} (J2000),
                  -3.0267d {-03d 01' 36.1"} (current),
                  -2.6158d {-02d 36' 56.7"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       101 [cnts]
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  39680.00 SOD {11:01:20.00} UT,   93.6 [sec] since BAT Trigger Time
CENTROID_X:      286.74,  raw= 287  [pixels]
CENTROID_Y:      296.65,  raw= 297  [pixels]
ROLL:            113.61 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -4.81
GRB_POS_XRT_Z:   -58.59
IMAGE_URL:       sw01273106000msxps_rw.img
SUN_POSTN:       256.82d {+17h 07m 16s}  -22.88d {-22d 52' 54"}
SUN_DIST:         67.10 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      358.86d {+23h 55m 27s}   -0.86d {-00d 51' 22"}
MOON_DIST:       167.80 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      297.46, 59.86 [deg] galactic lon,lat of the burst
ECL_COORDS:      190.43,  1.35 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:01:59 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1273106,   Seg_Num: 0
GRB_RA:          190.1137d {+12h 40m 27.28s} (J2000),
                 190.4345d {+12h 41m 44.28s} (current),
                 189.4709d {+12h 37m 53.01s} (1950)
GRB_DEC:          -2.8901d {-02d 53' 24.3"} (J2000),
                  -3.0267d {-03d 01' 36.1"} (current),
                  -2.6158d {-02d 36' 56.7"} (1950)
GRB_ERROR:       5.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       2.88e-09 [erg/cm2/sec]
GRB_SIGNIF:      10.04 [sigma]
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  39680.00 SOD {11:01:20.00} UT,   93.6 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.17 261.75 243.18
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       256.82d {+17h 07m 16s}  -22.88d {-22d 52' 54"}
SUN_DIST:         67.10 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      358.86d {+23h 55m 26s}   -0.86d {-00d 51' 26"}
MOON_DIST:       167.79 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      297.46, 59.86 [deg] galactic lon,lat of the burst
ECL_COORDS:      190.43,  1.35 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.70 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 11:03:39 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1273106,   Seg_Num: 0
GRB_RA:          190.111d {+12h 40m 27s} (J2000),
                 190.432d {+12h 41m 44s} (current),
                 189.468d {+12h 37m 52s} (1950)
GRB_DEC:          -2.879d {-02d 52' 42"} (J2000),
                  -3.015d {-03d 00' 54"} (current),
                  -2.604d {-02d 36' 14"} (1950)
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        39586.43 SOD {10:59:46.43} UT
TRIGGER_INDEX:   146
GRB_PHI:          37.45 [deg]
GRB_THETA:        26.87 [deg]
DELTA_TIME:      -31.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     29.98 [sigma]
IMAGE_SIGNIF:    12.99 [sigma]
LC_URL:          sw01273106000msb.lc
SUN_POSTN:       256.82d {+17h 07m 16s}  -22.88d {-22d 52' 54"}
SUN_DIST:         67.11 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      358.87d {+23h 55m 30s}   -0.85d {-00d 50' 58"}
MOON_DIST:       167.82 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:      297.46, 59.88 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      190.42,  1.36 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 10.34,-19.88 [deg].

GCN Circular #38488
The Fermi GBM team reports the detection of a likely LONG GRB
At 10:59:44 UT on 9 Dec 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241209D (trigger 755434789.093062 / 241209458).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 191.7, Dec = -2.2 (J2000 degrees, equivalent to J2000 12h 46m, -2d 12'), with a statistical uncertainty of 1.9 degrees.
The angle from the Fermi LAT boresight is 80.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_skymap_all_bn241209458.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/bn241209458/quicklook/glg_healpix_all_bn241209458.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209458/quicklook/glg_lc_medres34_bn241209458.gif
GCN Circular #38489
T. M. Parsotan (GSFC), E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC & INAF-OAR), J. J. DeLaunay (PSU), P. A. Evans (U Leicester), R. A. J. Eyles-Ferris (U Leicester) and A. Melandri (INAF-OAR) report on behalf of the Neil Gehrels Swift Observatory Team:
At 10:59:46 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 241209D (trigger=1273106). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 190.111, -2.879 which is
```
   RA(J2000) = 12h 40m 27s
   Dec(J2000) = -02d 52' 42"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 150 sec. The peak count rate was ~3200 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 11:01:20.0 UT, 93.6 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 190.1129, -2.8901 which is equivalent to:
```
   RA(J2000)  = 12h 40m 27.09s
   Dec(J2000) = -02d 53' 24.5"
```
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 41 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
The initial visibility window of the GRB was very short and no prompt UVOT data were generated. We await the full dataset to search for any UV/optical afterglow.
Burst Advocate for this burst is T. M. Parsotan (tyler.parsotan AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 12:02:49 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1273106,   Seg_Num: 0
POINT_RA:        190.125d {+12h 40m 30s} (J2000)
POINT_DEC:        -2.866d {-02d 51' 58"} (J2000)
POINT_ROLL:      113.627d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  43134.39 SOD {11:58:54.39} UT,   3548.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.300
N_STARS:         52
X_OFFSET:        482 [pixels]
Y_OFFSET:        676 [pixels]
X_MAX:           1441 [pixels]
Y_MAX:           1635 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01273106000msufc3547.fits
SUN_POSTN:       256.86d {+17h 07m 27s}  -22.89d {-22d 53' 08"}
SUN_DIST:         67.14 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      359.39d {+23h 57m 33s}   -0.57d {-00d 34' 12"}
MOON_DIST:       168.38 [deg]
MOON_ILLUM:      60 [%]
GAL_COORDS:      297.48, 59.89 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.43,  1.37 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 12:03:23 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1273106,   Seg_Num: 0
POINT_RA:        190.125d {+12h 40m 30s} (J2000)
POINT_DEC:        -2.866d {-02d 51' 58"} (J2000)
ROLL:            113.627d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  43134.39 SOD {11:58:54.39} UT,   3548.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     755438369
X_OFFSET:        801 [pixels]
Y_OFFSET:        995 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       961
Y_GRB_POS:       1155
BINNING_INDEX:   1
IM_URL:          sw01273106000msuni3582.fits
SUN_POSTN:       256.86d {+17h 07m 27s}  -22.89d {-22d 53' 08"}
SUN_DIST:         67.14 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      359.39d {+23h 57m 34s}   -0.57d {-00d 34' 02"}
MOON_DIST:       168.39 [deg]
MOON_ILLUM:      60 [%]
GAL_COORDS:      297.48, 59.89 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.43,  1.37 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 12:02:59 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1273106,   Seg_Num: 0
POINT_RA:        190.125d {+12h 40m 30s} (J2000)
POINT_DEC:        -2.866d {-02d 51' 58"} (J2000)
POINT_ROLL:      113.627d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  43134.39 SOD {11:58:54.39} UT,   3548.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.300
N_STARS:         52
X_OFFSET:        482 [pixels]
Y_OFFSET:        676 [pixels]
X_MAX:           1441 [pixels]
Y_MAX:           1635 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01273106000msufc3547.fits
SUN_POSTN:       256.86d {+17h 07m 27s}  -22.89d {-22d 53' 08"}
SUN_DIST:         67.14 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      359.39d {+23h 57m 33s}   -0.57d {-00d 34' 09"}
MOON_DIST:       168.38 [deg]
MOON_ILLUM:      60 [%]
GAL_COORDS:      297.48, 59.89 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.43,  1.37 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 12:03:31 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1273106,   Seg_Num: 0
POINT_RA:        190.125d {+12h 40m 30s} (J2000)
POINT_DEC:        -2.866d {-02d 51' 58"} (J2000)
ROLL:            113.627d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  43134.39 SOD {11:58:54.39} UT,   3548.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     755438369
X_OFFSET:        801 [pixels]
Y_OFFSET:        995 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       961
Y_GRB_POS:       1155
BINNING_INDEX:   1
IM_URL:          sw01273106000msuni3582.fits
SUN_POSTN:       256.86d {+17h 07m 27s}  -22.89d {-22d 53' 08"}
SUN_DIST:         67.14 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:      359.39d {+23h 57m 34s}   -0.57d {-00d 34' 00"}
MOON_DIST:       168.39 [deg]
MOON_ILLUM:      60 [%]
GAL_COORDS:      297.48, 59.89 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.43,  1.37 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #38491
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 1140 s of XRT Photon Counting mode data and 4 UVOT images for GRB 241209D, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 190.11190, -2.89162 which is equivalent to:
```
RA (J2000): 12h 40m 26.86s
Dec (J2000): -02d 53' 29.8"
```
with an uncertainty of 2.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #38498
V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Swift GRB 241209D ( T. M. Parsotan et al., GCN 38489) errorbox 33929 sec after notice time and 33951 sec after trigger time at 2024-12-09 20:25:37 UT, with upper limit up to 18.8 mag. The observations began at zenith distance = 75 deg. The sun altitude is -41.5 deg.
The galactic latitude b = 60 deg., longitude l = 299 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2701233
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   34041 |        MASTER-Tunka |   C |   180 | 15.0 |        
   35265 |        MASTER-Tunka |   C |   180 | 18.8 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #38503
V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 241209D ( Fermi GBM team, GCN 38488) errorbox 33914 sec after notice time and 33953 sec after trigger time at 2024-12-09 20:25:37 UT, with upper limit up to 19.2 mag. The observations began at zenith distance = 75 deg. The sun altitude is -41.5 deg.
The galactic latitude b = 60 deg., longitude l = 302 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2701308
We obtain a following upper limits.
```
Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   34044 | 2024-12-09 20:25:37 |        MASTER-Tunka | (12h 40m 42.72s , -02d 49m 30.7s) |   C |   180 | 15.0 |        
   34224 | 2024-12-09 20:25:37 |        MASTER-Tunka | (12h 40m 42.76s , -02d 49m 32.4s) |   C |   540 | 19.2 |  Coadd 
   35267 | 2024-12-09 20:46:01 |        MASTER-Tunka | (12h 40m 48.04s , -02d 50m 25.9s) |   C |   180 | 18.8 |        
   36758 | 2024-12-09 21:10:52 |        MASTER-Tunka | (12h 40m 47.42s , -02d 47m 55.6s) |   C |   180 | 19.0 |        
   37967 | 2024-12-09 21:31:01 |        MASTER-Tunka | (12h 40m 42.47s , -02d 48m 50.9s) |   C |   180 | 19.3 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #38505
J.-G. Ducoin (CPPM), Francesco Magnani (CPPM), Damien Dornic (CPPM), Alan M. Watson (UNAM), Margarita Pereyra (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), S. Antier (OCA), Jean-Luc Atteia (IRAP), Nathaniel R. Butler (ASU), Francis Fortin (IRAP) and Simona Lombardo (LAM), report:
We imaged the field of GRB 241209D detected by Swift/BAT and Fermi/GBM (GCN Circ. 38488, 38489, 38491) during the commissioning of the COLIBRÍ (SVOM/F-GFT) telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in Mexico.
The observations started 21 minutes after the GRB trigger. We observed with the engineering test camera in a red filter that approximates SDSS r. The data were reduced using custom software and then analysed and calibrated against the PS1 catalog using the STDWeb service (Karpov et al. 2022).
In 4260 seconds of exposure from 2024/12/09 11:20:50 (UT) to 12:59:15, we detect the optical counterpart with:
r = 20.04 +/-0.05 (SNR ~21.6)
This source is right next to a catalogued galaxy in PAN-STARRs with rmag of ~21.44. Given the significant difference in magnitude and the slight visible offset with the PAN-STARRs object position, we consider this to be the Afterglow of GRB 241209D.
We warmly thank the COLIBRI engineering team and the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir.
GCN Circular #38507
C. Malacaria (INAF-OAR) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 10:59:44.09 UT on 09 December 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241209D (trigger 755434789/241209458). which was also detected by Swift BAT (T. M. Parsotan et al. 2024, GCN 38489, M.R. Goad et al. 2024, GCN 38491). The Fermi GBM on-ground location is consistent with the Swift BAT position.
The angle from the Fermi LAT boresight is 82 degrees.
The GBM light curve consists of a single emission episode with a duration (T90) of about 45 s (50-300 keV). The time-averaged spectrum from T0-0.8 to T0+44.3 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.40 +/- 0.07 and the cutoff energy, parameterized as Epeak, is 110 +/- 3 keV.
The event fluence (10-1000 keV) in this time interval is (9.5 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+5.9 s in the 10-1000 keV band is 4.4 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well with Epeak= 107 +/- 4 keV, alpha = -0.35 +/- 0.08 and beta = -3.4 +/- 0.6.
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 #38508
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), S. Dichiara (PSU), J.A. Kennea (PSU), D.N. Burrows (PSU) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 6.4 ks of XRT data for GRB 241209D, from 260 s to 37.7 ks after the BAT trigger. The data comprise 22 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode.
The light curve can be modelled with an initial power-law decay with an index of alpha=4.3 (+3.4, -2.5), followed by a break at T+626 s to an alpha of 0.66 (+/-0.13).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.89 (+0.29, -0.26). The best-fitting absorption column is 5.9 (+6.9, -3.6) x 10^20 cm^-2, consistent with the Galactic value of 2.3 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     5.9 (+6.9, -3.6) x 10^20 cm^-2
Galactic foreground: 2.3 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.89 (+0.29, -0.26)
```
If the light curve continues to decay with a power-law decay index of 0.66, the count rate at T+24 hours will be 0.014 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.1 x 10^-13 (5.8 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01273106.
This circular is an official product of the Swift-XRT team.
GCN Circular #38518
M. Tembhurnikar (IUCAA), G. Waratkar (IITB), A. Dasgupta (BITS Pilani, Hyderabad), J. Joshi (IUCAA), 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 CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 241209D which was also detected by Fermi/GBM (Fermi-GBM Team, GCN Circ. 38507), and Swift/BAT (Page et al., GCN Circ. 38508).
The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-12-09 10:59:47.1 UTC. The measured peak count rate associated with the burst is 739 (+62, -67) counts/s above the background in the combined data of all quadrants, with a total of 9569 (+1176, -1291) counts. The local mean background count rate was 6618 (+7, -8) counts/s. We measure a T90 of 26 (+5, -6) 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 #38526
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
The long-duration GRB 241209D (Fermi-GBM detection: Fermi GBM team, GCN 38488; Malacaria & Meegan, GCN 38507; Swift-BAT detection: Parsotan et al., GCN 38489; AstroSat CZTI detection: Tembhurnikar et al., GCN 38518) was detected by Konus-Wind (KW) in the waiting mode.
A Bayesian block analysis of the KW waiting mode data in the 20-300 keV band reveals a >13 sigma count rate increase in the interval from T0-2.0 s to T0+42.160 s where T0 = T0(BAT) = 10:59:45.649 UT.
The KW light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB241209D/
Modeling a time-integrated spectrum of the burst (from T0-2.0 s to T0+42.160 s) by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep): yields alpha = -1.16 (-0.37, +4.03) and Ep = 90(-12,+14) keV.
The total burst fluence is 8.79(-0.87,+1.74)x10^-6 erg/cm^2, and the 2.944 s peak energy flux, measured from T0-2.0 s, is 5.86(-0.75,+1.25)x10^-7 erg/cm^2. (both in the 20 keV - 10 MeV energy range).
All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 13 Dec 24 02:22:33 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     1273106,   Seg_Num: 0
GRB_RA:          190.1137d {+12h 40m 27.2s} (J2000),
                 190.4345d {+12h 41m 44.2s} (current),
                 189.4709d {+12h 37m 53.0s} (1950)
GRB_DEC:          -2.8901d {-02d 53' 24.3"} (J2000),
                  -3.0267d {-03d 01' 36.1"} (current),
                  -2.6158d {-02d 36' 56.7"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       101 [cnts]
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  39680.00 SOD {11:01:20.00} UT,   31339.9 [sec] since BAT Trigger Time
CENTROID_X:      286.74,  raw= 287  [pixels]
CENTROID_Y:      296.65,  raw= 297  [pixels]
ROLL:            113.61 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -4.81
GRB_POS_XRT_Z:   -58.59
IMAGE_URL:       sw01273106000msxps_rw.img
SUN_POSTN:       260.82d {+17h 23m 17s}  -23.17d {-23d 10' 01"}
SUN_DIST:         70.80 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:       47.55d {+03h 10m 12s}  +21.68d {+21d 40' 51"}
MOON_DIST:       139.42 [deg]
MOON_ILLUM:      93 [%]
GAL_COORDS:      297.46, 59.86 [deg] galactic lon,lat of the burst
ECL_COORDS:      190.43,  1.35 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN Circular #38527
R.Brivio, M. Ferro, P. D’Avanzo, Y.-D. Hu, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team:
We observed the field of GRB 241209D detected by Swift/BAT (Parsotan et al., GCN 38489) and Fermi/GBM (Fermi GBM team, GCN 38488) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2024 December 10 at 06:54:39 UT (i.e. 19.9 hours after the Swift trigger), and lasting for about 1 hour.
From preliminary photometry we do not detect the optical counterpart (Ducoin et al., GCN 38505) in the optical and NIR images at the Swift-XRT enhanced position (Goad et al., GCN 38491) down to the following 3sigma magnitude upper limits:
r > 20.3 (AB; calibrated against the PanSTARRS catalogue) at a mid-time of t - t0 = 20.4 hr after the trigger,
J > 18.1 (Vega; calibrated against the 2MASS catalogue) at a mid-time of t - t0 = 20.5 hr after the trigger.
GCN Circular #38569
A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration:
The long GRB 241209D (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ 38488; Swift detection of a burst: Parsotan et al., GCN Circ 38489; Fermi GBM Observation: Malacaria et al., GCN Circ 38507; AstroSat CZTI detection: Tembhurnikar et al., GCN Circ 38518; Konus-Wind detection: Ridnaia et al., GCN Circ 38526) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 10:59:46.760 UTC on 9 December 2024 (https://cgbm.calet.jp/cgbm_trigger/flight/1417777157/index.html). The burst signal was seen by only the SGM detector. Because of a problem with the ground alert processing script, the GCN notice was not distributed automatically for this event.
The burst light curve shows a single pulse that starts at T-4.0 sec, peaks at T+0.6 sec, and ends at T+6.7 sec. The T90 and T50 durations measured by the SGM data are 9.2 +/- 0.7 sec and 4.6 +/- 0.4 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
https://cgbm.calet.jp/cgbm_trigger/ground/1417777157/
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at Waseda University.
GCN Circular #38589
M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 241209D (Fermi/GBM detection: GCN 38488; Swift/BAT detection: GCN 38489; AstroSat/CZTI detection: GCN 38518; Konus/Wind detection: GCN 38526; CALET/CGBM detection: GCN 38569) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).
The detection was confirmed at the peak time 2024-12-09 10:59:45.2 UTC. The T90 duration measured by GRBAlpha is 52 s and the overall significance during T90 reaches 11 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB241209D_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.

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Jochen Greiner, last update: 17-Dec-2024 [Disclaimer]