Gamma-ray Burst 241209A

(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 05:38:55 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1273071,   Seg_Num: 0
GRB_RA:          155.376d {+10h 21m 30s} (J2000),
                 155.702d {+10h 22m 48s} (current),
                 154.722d {+10h 18m 53s} (1950)
GRB_DEC:          +6.316d {+06d 18' 58"} (J2000),
                  +6.190d {+06d 11' 23"} (current),
                  +6.568d {+06d 34' 06"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       917 [cnts]    Image_Peak=86 [image_cnts]
TRIGGER_DUR:     0.256 [sec] 
TRIGGER_INDEX:   123     E_range: 25-100 keV
BKG_INTEN:       16075 [cnts]
BKG_TIME:        20133.32 SOD {05:35:33.32} UT
BKG_DUR:         8 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        20144.07 SOD {05:35:44.07} UT
GRB_PHI:           2.19 [deg]
GRB_THETA:        33.33 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     17.46 [sigma]
IMAGE_SIGNIF:    8.18 [sigma]
MERIT_PARAMS:     +1  +0  +0  -2  +2  -2  +0  +0 +21  +0 
SUN_POSTN:       256.57d {+17h 06m 17s}  -22.86d {-22d 51' 38"}
SUN_DIST:        102.39 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.07d {+23h 44m 16s}   -2.38d {-02d 22' 40"}
MOON_DIST:       159.34 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.77 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      154.88, -3.66 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trig ger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
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 = 261.81,18.19 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(0.0<100sec) coincident with the FERMI_GBM event (trignum=755415349).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Dec 24 05:35:47 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      49
TRIGGER_NUM:     755415349
GRB_RA:          152.383d {+10h 09m 32s} (J2000),
                 152.714d {+10h 10m 51s} (current),
                 151.721d {+10h 06m 53s} (1950)
GRB_DEC:          +9.550d {+09d 33' 00"} (J2000),
                  +9.427d {+09d 25' 36"} (current),
                  +9.796d {+09d 47' 45"} (1950)
GRB_ERROR:       22.35 [deg radius, statistical plus systematic]
GRB_INTEN:       391 [cnts/sec]
DATA_SIGNIF:     6.60 [sigma]
INTEG_TIME:      0.128 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        20144.16 SOD {05:35:44.16} UT
GRB_PHI:         104.00 [deg]
GRB_THETA:        75.00 [deg]
DATA_TIME_SCALE: 0.1280 [sec]
HARD_RATIO:      0.35
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       0,0,0, 0,0,0, 0,0,0, 1,1,0, 0,0,
SUN_POSTN:       256.57d {+17h 06m 16s}  -22.86d {-22d 51' 38"}
SUN_DIST:        106.34 [deg]   Sun_angle= 6.9 [hr] (West of Sun)
MOON_POSTN:      356.04d {+23h 44m 09s}   -2.39d {-02d 23' 33"}
MOON_DIST:       155.77 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      229.82, 48.01 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      150.95, -1.70 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209233/quicklook/glg_lc_medres34_bn241209233.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 267.32,-7.15 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 09 Dec 24 05:36:02 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      59
TRIGGER_NUM:     755415349
GRB_RA:          158.450d {+10h 33m 48s} (J2000),
                 158.787d {+10h 35m 09s} (current),
                 157.774d {+10h 31m 06s} (1950)
GRB_DEC:         +18.870d {+18d 52' 12"} (J2000),
                 +18.741d {+18d 44' 27"} (current),
                 +19.128d {+19d 07' 42"} (1950)
GRB_ERROR:       11.54 [deg radius, statistical only]
DATA_SIGNIF:     7.00 [sigma]
DATA_INTERVAL:   0.128 [sec]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        20144.16 SOD {05:35:44.16} UT
GRB_PHI:         104.00 [deg]
GRB_THETA:        86.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       256.57d {+17h 06m 16s}  -22.86d {-22d 51' 38"}
SUN_DIST:        104.06 [deg]   Sun_angle= 6.5 [hr] (West of Sun)
MOON_POSTN:      356.04d {+23h 44m 10s}   -2.39d {-02d 23' 28"}
MOON_DIST:       156.49 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      220.19, 57.38 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      153.05,  9.12 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209233/quicklook/glg_lc_medres34_bn241209233.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_755415349.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:     Mon 09 Dec 24 05:45:01 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     755415349
GRB_RA:          155.140d {+10h 20m 34s} (J2000),
                 155.470d {+10h 21m 53s} (current),
                 154.478d {+10h 17m 55s} (1950)
GRB_DEC:         +10.220d {+10d 13' 12"} (J2000),
                 +10.094d {+10d 05' 38"} (current),
                 +10.472d {+10d 28' 19"} (1950)
GRB_ERROR:       12.78 [deg radius, statistical only]
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        20144.16 SOD {05:35:44.16} UT
GRB_PHI:         102.00 [deg]
GRB_THETA:        77.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       256.57d {+17h 06m 18s}  -22.86d {-22d 51' 40"}
SUN_DIST:        104.05 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.12d {+23h 44m 28s}   -2.35d {-02d 20' 57"}
MOON_DIST:       158.08 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      231.05, 50.69 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      153.25, -0.10 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209233/quicklook/glg_lc_medres34_bn241209233.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209233/quicklook/glg_locplot_all_bn241209233.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 Short GRB.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=1273071).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 05:39:23 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.365d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.311d {+06d 18' 40"} (J2000)
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20250.64 SOD {05:37:30.64} UT,   106.6 [sec] since BAT Trigger Time
COUNTS:          47    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        4    Max_iter_allowed= 4
ERROR_CODE:      2
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        Algorithm did not converge; too many iterations.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 05:40:00 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1273071,   Seg_Num: 0
GRB_RA:          155.376d {+10h 21m 30s} (J2000),
                 155.702d {+10h 22m 48s} (current),
                 154.722d {+10h 18m 53s} (1950)
GRB_DEC:          +6.316d {+06d 18' 58"} (J2000),
                  +6.190d {+06d 11' 23"} (current),
                  +6.568d {+06d 34' 06"} (1950)
GRB_DATE:        20653 TJD;   344 DOY;   24/12/09
GRB_TIME:        20144.07 SOD {05:35:44.07} UT
TRIGGER_INDEX:   123
GRB_PHI:           2.19 [deg]
GRB_THETA:        33.33 [deg]
DELTA_TIME:      45.00 [sec]
TRIGGER_DUR:     0.256 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     17.46 [sigma]
IMAGE_SIGNIF:    8.18 [sigma]
LC_URL:          sw01273071000msb.lc
SUN_POSTN:       256.57d {+17h 06m 17s}  -22.86d {-22d 51' 39"}
SUN_DIST:        102.39 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.07d {+23h 44m 18s}   -2.37d {-02d 22' 21"}
MOON_DIST:       159.33 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.77 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      154.88, -3.66 [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 = 261.81,18.19 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 05:40:33 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.365d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.312d {+06d 18' 42"} (J2000)
POINT_ROLL:      112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20253.84 SOD {05:37:33.84} UT,   109.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.746
N_STARS:         17
X_OFFSET:        504 [pixels]
Y_OFFSET:        484 [pixels]
X_MAX:           1463 [pixels]
Y_MAX:           1443 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw01273071000msufc0109.fits
SUN_POSTN:       256.57d {+17h 06m 17s}  -22.86d {-22d 51' 39"}
SUN_DIST:        102.40 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.08d {+23h 44m 19s}   -2.37d {-02d 22' 12"}
MOON_DIST:       159.32 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.67 [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 05:40:50 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.365d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.312d {+06d 18' 42"} (J2000)
POINT_ROLL:      112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20253.84 SOD {05:37:33.84} UT,   109.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.746
N_STARS:         17
X_OFFSET:        504 [pixels]
Y_OFFSET:        484 [pixels]
X_MAX:           1463 [pixels]
Y_MAX:           1443 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw01273071000msufc0109.fits
SUN_POSTN:       256.57d {+17h 06m 17s}  -22.86d {-22d 51' 39"}
SUN_DIST:        102.40 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.08d {+23h 44m 20s}   -2.37d {-02d 22' 07"}
MOON_DIST:       159.31 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.67 [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 05:41:55 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.365d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.312d {+06d 18' 42"} (J2000)
ROLL:            112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20253.84 SOD {05:37:33.84} UT,   109.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     755415488
X_OFFSET:        823 [pixels]
Y_OFFSET:        803 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       983
Y_GRB_POS:       963
BINNING_INDEX:   1
IM_URL:          sw01273071000msuni0144.fits
SUN_POSTN:       256.57d {+17h 06m 17s}  -22.86d {-22d 51' 39"}
SUN_DIST:        102.40 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.09d {+23h 44m 22s}   -2.36d {-02d 21' 49"}
MOON_DIST:       159.30 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.67 [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 05:42:09 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.365d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.312d {+06d 18' 42"} (J2000)
ROLL:            112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20253.84 SOD {05:37:33.84} UT,   109.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     755415488
X_OFFSET:        823 [pixels]
Y_OFFSET:        803 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       983
Y_GRB_POS:       963
BINNING_INDEX:   1
IM_URL:          sw01273071000msuni0144.fits
SUN_POSTN:       256.57d {+17h 06m 17s}  -22.86d {-22d 51' 39"}
SUN_DIST:        102.40 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.09d {+23h 44m 22s}   -2.36d {-02d 21' 45"}
MOON_DIST:       159.30 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.67 [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 #38474
The Fermi GBM team reports the detection of a likely SHORT GRB
At 05:35:44 UT on 9 Dec 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241209A (trigger 755415349.162358 / 241209233).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 155.1, Dec = 10.2 (J2000 degrees, equivalent to J2000 10h 20m, 10d 11'), with a statistical uncertainty of 12.8 degrees.
The angle from the Fermi LAT boresight is 77.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209233/quicklook/glg_skymap_all_bn241209233.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/bn241209233/quicklook/glg_healpix_all_bn241209233.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241209233/quicklook/glg_lc_medres34_bn241209233.gif

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 05:46:51 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.366d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.313d {+06d 18' 46"} (J2000)
POINT_ROLL:      112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20467.24 SOD {05:41:07.24} UT,   323.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.736
N_STARS:         23
X_OFFSET:        264 [pixels]
Y_OFFSET:        244 [pixels]
X_MAX:           1703 [pixels]
Y_MAX:           1683 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw01273071000msufc0323.fits
SUN_POSTN:       256.58d {+17h 06m 18s}  -22.86d {-22d 51' 40"}
SUN_DIST:        102.41 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.13d {+23h 44m 32s}   -2.34d {-02d 20' 26"}
MOON_DIST:       159.26 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.66 [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 05:53:14 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.366d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.313d {+06d 18' 46"} (J2000)
POINT_ROLL:      112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  21022.92 SOD {05:50:22.92} UT,   878.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.799
N_STARS:         40
X_OFFSET:        264 [pixels]
Y_OFFSET:        244 [pixels]
X_MAX:           1703 [pixels]
Y_MAX:           1683 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw01273071000msufc0878.fits
SUN_POSTN:       256.58d {+17h 06m 19s}  -22.86d {-22d 51' 42"}
SUN_DIST:        102.41 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.19d {+23h 44m 45s}   -2.31d {-02d 18' 38"}
MOON_DIST:       159.20 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.66 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN Circular #38475
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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB241209.23 (trigger No 1273071,10h 21m 30.24s , +06d 18m 57.6s, R=0.05) errorbox 38 sec after notice time and 236 sec after trigger time at 2024-12-09 05:39:40 UT, with upper limit up to 19.2 mag. The observations began at zenith distance = 69 deg. The sun altitude is -33.4 deg.
The galactic latitude b = 49 deg., longitude l = 237 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2701042
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

     261 |         MASTER-OAFA |   C |    50 | 19.3 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 05:53:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.366d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.313d {+06d 18' 46"} (J2000)
POINT_ROLL:      112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  21022.92 SOD {05:50:22.92} UT,   878.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.799
N_STARS:         40
X_OFFSET:        264 [pixels]
Y_OFFSET:        244 [pixels]
X_MAX:           1703 [pixels]
Y_MAX:           1683 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw01273071000msufc0878.fits
SUN_POSTN:       256.58d {+17h 06m 19s}  -22.86d {-22d 51' 42"}
SUN_DIST:        102.41 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.19d {+23h 44m 46s}   -2.31d {-02d 18' 33"}
MOON_DIST:       159.20 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.66 [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 05:54:46 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.366d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.313d {+06d 18' 46"} (J2000)
ROLL:            112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  21022.92 SOD {05:50:22.92} UT,   878.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     755416257
X_OFFSET:        823 [pixels]
Y_OFFSET:        803 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       983
Y_GRB_POS:       963
BINNING_INDEX:   1
IM_URL:          sw01273071000msuni0913.fits
SUN_POSTN:       256.58d {+17h 06m 19s}  -22.86d {-22d 51' 42"}
SUN_DIST:        102.41 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.20d {+23h 44m 49s}   -2.30d {-02d 18' 12"}
MOON_DIST:       159.18 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.66 [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 05:55:00 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.366d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.313d {+06d 18' 46"} (J2000)
ROLL:            112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  21022.92 SOD {05:50:22.92} UT,   878.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     755416257
X_OFFSET:        823 [pixels]
Y_OFFSET:        803 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       983
Y_GRB_POS:       963
BINNING_INDEX:   1
IM_URL:          sw01273071000msuni0913.fits
SUN_POSTN:       256.58d {+17h 06m 20s}  -22.86d {-22d 51' 42"}
SUN_DIST:        102.41 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.20d {+23h 44m 49s}   -2.30d {-02d 18' 08"}
MOON_DIST:       159.18 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.66 [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 #38476
T. M. Parsotan (GSFC), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC & INAF-OAR), R. Gupta (NASA GSFC), D. M. Palmer (LANL) and A. Tohuvavohu (Caltech) report on behalf of the Neil Gehrels Swift Observatory Team:
At 05:35:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 241209A (trigger=1273071). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 155.376, +6.316 which is
```
   RA(J2000) = 10h 21m 30s
   Dec(J2000) = +06d 18' 58"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single short peak structure with a duration of about 0.25 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 05:37:30.6 UT, 106.6 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 109 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.024.
Although we do not yet have an XRT or UVOT counterpart, we believe this is a true GRB. It is high significance (>8 sigma) in the BAT image and Fermi-GBM also detected the event.
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 05:48:13 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.366d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.313d {+06d 18' 46"} (J2000)
ROLL:            112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20467.24 SOD {05:41:07.24} UT,   323.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     755415701
X_OFFSET:        823 [pixels]
Y_OFFSET:        803 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       983
Y_GRB_POS:       963
BINNING_INDEX:   1
IM_URL:          sw01273071000msuni0358.fits
SUN_POSTN:       256.58d {+17h 06m 18s}  -22.86d {-22d 51' 41"}
SUN_DIST:        102.41 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.15d {+23h 44m 35s}   -2.33d {-02d 20' 03"}
MOON_DIST:       159.25 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.66 [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 05:48:21 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.366d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.313d {+06d 18' 46"} (J2000)
ROLL:            112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20467.24 SOD {05:41:07.24} UT,   323.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     755415701
X_OFFSET:        823 [pixels]
Y_OFFSET:        803 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       983
Y_GRB_POS:       963
BINNING_INDEX:   1
IM_URL:          sw01273071000msuni0358.fits
SUN_POSTN:       256.58d {+17h 06m 18s}  -22.86d {-22d 51' 41"}
SUN_DIST:        102.41 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.15d {+23h 44m 35s}   -2.33d {-02d 20' 00"}
MOON_DIST:       159.25 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.66 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 09 Dec 24 05:47:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1273071,   Seg_Num: 0
POINT_RA:        155.366d {+10h 21m 28s} (J2000)
POINT_DEC:        +6.313d {+06d 18' 46"} (J2000)
POINT_ROLL:      112.078d
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20467.24 SOD {05:41:07.24} UT,   323.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.736
N_STARS:         23
X_OFFSET:        264 [pixels]
Y_OFFSET:        244 [pixels]
X_MAX:           1703 [pixels]
Y_MAX:           1683 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw01273071000msufc0323.fits
SUN_POSTN:       256.58d {+17h 06m 18s}  -22.86d {-22d 51' 40"}
SUN_DIST:        102.41 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.14d {+23h 44m 33s}   -2.34d {-02d 20' 22"}
MOON_DIST:       159.26 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.87, -3.66 [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 06:17:13 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1273071,   Seg_Num: 0
GRB_RA:          155.3970d {+10h 21m 35.27s} (J2000),
                 155.7228d {+10h 22m 53.48s} (current),
                 154.7432d {+10h 18m 58.36s} (1950)
GRB_DEC:          +6.3282d {+06d 19' 41.5"} (J2000),
                  +6.2018d {+06d 12' 06.4"} (current),
                  +6.5807d {+06d 34' 50.3"} (1950)
GRB_ERROR:       1.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  20653 TJD;   344 DOY;   24/12/09
IMG_START_TIME:  20298.00 SOD {05:38:18.00} UT,   153.9 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       256.60d {+17h 06m 24s}  -22.86d {-22d 51' 47"}
SUN_DIST:        102.40 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      356.40d {+23h 45m 35s}   -2.20d {-02d 11' 52"}
MOON_DIST:       159.00 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:      236.33, 48.80 [deg] galactic lon,lat of the burst
ECL_COORDS:      154.89, -3.64 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 1.1% < P(seren) < 2.8%.

GCN Circular #38479
K.L. Page and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using promptly downlinked XRT event data for GRB 241209A, we find a fading X-ray source with an enhanced position: RA,Dec = 155.39704, 6.32828 (degrees) which is equivalent to:
```
RA  (J2000.0) = 10 21 35.29
DEC (J2000.0) = +06 19 41.8
```
with an uncertainty of 1.9 arcsec (radius, 90% containment). This location is 87.3 arcseconds from the BAT onboard position, inside the BAT error circle. Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/1273071 .
Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular #38481
A. Kumar, B. P. Gompertz, R. Starling, K. Ackley, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, D. O'Neill, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Palle and D. Pollacco report on behalf of the GOTO collaboration:
The Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) observed the field of Fermi and Swift detected GRB 241209A (Fermi GBM Team, GCN 38474; Parsotan et al., GCN 38476; Page et al. GCN 38479) at 05:42:56 and 05:50:51 UT on 2024-12-09 (7.22 and 15.12 minutes post-trigger, respectively). The observations were taken by GOTO-N, and consisted of 4x90s exposures in the GOTO L-band (400-700 nm).
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using deeper template observations of the same pointings.
No new optical source within the Swift-XRT localisation region (Page et al. GCN 38479) is identified to a 3-sigma limiting magnitude of L > 20.5.
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).

GCN Circular #38483
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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 241209A ( Fermi GBM team, GCN 38474) errorbox 227 sec after notice time and 235 sec after trigger time at 2024-12-09 05:39:39 UT, with upper limit up to 20.5 mag. The observations began at zenith distance = 67 deg. The sun altitude is -33.4 deg.
The galactic latitude b = 51 deg., longitude l = 232 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2701058
We obtain a following upper limits.

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

     251 | 2024-12-09 05:39:39 |         MASTER-OAFA | (10h 12m 15.63s , +05d 54m 10.8s) |   C |    30 | 18.0 |        
     296 | 2024-12-09 05:39:39 |         MASTER-OAFA | (10h 12m 15.64s , +05d 54m 10.7s) |   C |   120 | 19.0 |  Coadd 
     261 | 2024-12-09 05:39:40 |         MASTER-OAFA | (10h 21m 18.86s , +06d 18m 30.9s) |   C |    50 | 19.3 |        
     326 | 2024-12-09 05:39:40 |         MASTER-OAFA | (10h 21m 18.86s , +06d 18m 30.9s) |   C |   180 | 20.2 |  Coadd 
     406 | 2024-12-09 05:39:40 |         MASTER-OAFA | (10h 21m 18.86s , +06d 18m 31.0s) |   C |   340 | 20.4 |  Coadd 
     313 | 2024-12-09 05:40:36 |         MASTER-OAFA | (10h 12m 15.85s , +05d 54m 17.5s) |   C |    40 | 18.4 |        
     323 | 2024-12-09 05:40:37 |         MASTER-OAFA | (10h 21m 18.99s , +06d 18m 35.4s) |   C |    60 | 19.4 |        
     384 | 2024-12-09 05:41:43 |         MASTER-OAFA | (10h 12m 16.07s , +05d 54m 23.9s) |   C |    50 | 18.4 |        
     394 | 2024-12-09 05:41:43 |         MASTER-OAFA | (10h 21m 19.13s , +06d 18m 39.9s) |   C |    70 | 19.5 |        
     470 | 2024-12-09 05:42:59 |         MASTER-OAFA | (10h 12m 16.31s , +05d 54m 30.7s) |   C |    70 | 18.7 |        
     570 | 2024-12-09 05:42:59 |         MASTER-OAFA | (10h 12m 16.31s , +05d 54m 30.7s) |   C |   270 | 19.6 |  Coadd 
     480 | 2024-12-09 05:42:59 |         MASTER-OAFA | (10h 21m 19.30s , +06d 18m 45.9s) |   C |    90 | 19.7 |        
     557 | 2024-12-09 05:42:59 |         MASTER-OAFA | (10h 21m 19.30s , +06d 18m 45.9s) |   C | 243.333 | 20.2 |  Coadd 
     576 | 2024-12-09 05:44:34 |         MASTER-OAFA | (10h 12m 16.50s , +05d 54m 39.2s) |   C |    90 | 18.7 |        
     586 | 2024-12-09 05:44:35 |         MASTER-OAFA | (10h 21m 19.52s , +06d 18m 52.6s) |   C |   110 | 19.8 |        
     702 | 2024-12-09 05:46:31 |         MASTER-OAFA | (10h 12m 16.72s , +05d 54m 48.5s) |   C |   110 | 18.9 |        
     670 | 2024-12-09 05:46:31 |         MASTER-OAFA | (10h 21m 19.64s , +06d 18m 58.1s) |   C | 43.3333 | 19.3 |        
     718 | 2024-12-09 05:47:20 |         MASTER-OAFA | (10h 21m 19.70s , +06d 19m 01.2s) |   C | 43.3333 | 19.3 |        
     766 | 2024-12-09 05:47:20 |         MASTER-OAFA | (10h 21m 19.70s , +06d 19m 01.2s) |   C |   140 | 20.1 |  Coadd 
     767 | 2024-12-09 05:48:09 |         MASTER-OAFA | (10h 21m 19.77s , +06d 19m 04.5s) |   C | 43.3333 | 19.2 |        
     865 | 2024-12-09 05:48:58 |         MASTER-OAFA | (10h 12m 16.88s , +05d 54m 59.0s) |   C |   140 | 19.1 |        
    1025 | 2024-12-09 05:48:58 |         MASTER-OAFA | (10h 12m 16.87s , +05d 54m 59.1s) |   C |   460 | 19.8 |  Coadd 
     822 | 2024-12-09 05:48:59 |         MASTER-OAFA | (10h 21m 19.85s , +06d 19m 07.6s) |   C | 53.3333 | 19.3 |        
     881 | 2024-12-09 05:49:58 |         MASTER-OAFA | (10h 21m 19.93s , +06d 19m 11.0s) |   C | 53.3333 | 19.4 |        
     937 | 2024-12-09 05:49:58 |         MASTER-OAFA | (10h 21m 19.94s , +06d 19m 11.0s) |   C | 166.667 | 20.2 |  Coadd 
     940 | 2024-12-09 05:50:57 |         MASTER-OAFA | (10h 21m 20.02s , +06d 19m 14.4s) |   C | 53.3333 | 19.5 |        
    1052 | 2024-12-09 05:51:56 |         MASTER-OAFA | (10h 12m 16.99s , +05d 55m 09.4s) |   C |   160 | 19.2 |        
    1003 | 2024-12-09 05:51:56 |         MASTER-OAFA | (10h 21m 20.07s , +06d 19m 18.2s) |   C |    60 | 19.6 |        
    1068 | 2024-12-09 05:53:02 |         MASTER-OAFA | (10h 21m 20.14s , +06d 19m 21.3s) |   C |    60 | 19.7 |        
    1128 | 2024-12-09 05:53:02 |         MASTER-OAFA | (10h 21m 20.14s , +06d 19m 21.3s) |   C |   180 | 20.3 |  Coadd 
    1134 | 2024-12-09 05:54:08 |         MASTER-OAFA | (10h 21m 20.24s , +06d 19m 25.2s) |   C |    60 | 19.7 |        
    1250 | 2024-12-09 05:55:14 |         MASTER-OAFA | (10h 12m 17.16s , +05d 55m 20.1s) |   C |   160 | 19.2 |        
    1200 | 2024-12-09 05:55:14 |         MASTER-OAFA | (10h 21m 20.36s , +06d 19m 28.9s) |   C |    60 | 19.6 |        
    1266 | 2024-12-09 05:56:19 |         MASTER-OAFA | (10h 21m 20.42s , +06d 19m 32.6s) |   C |    60 | 19.8 |        
    1326 | 2024-12-09 05:56:19 |         MASTER-OAFA | (10h 21m 20.42s , +06d 19m 32.6s) |   C |   180 | 20.4 |  Coadd 
    1331 | 2024-12-09 05:57:25 |         MASTER-OAFA | (10h 21m 20.47s , +06d 19m 36.0s) |   C |    60 | 19.8 |        
    1447 | 2024-12-09 05:58:30 |         MASTER-OAFA | (10h 12m 17.12s , +05d 55m 29.3s) |   C |   160 | 19.3 |        
    1607 | 2024-12-09 05:58:30 |         MASTER-OAFA | (10h 12m 17.12s , +05d 55m 29.3s) |   C |   480 | 19.9 |  Coadd 
    1397 | 2024-12-09 05:58:31 |         MASTER-OAFA | (10h 21m 20.50s , +06d 19m 39.6s) |   C |    60 | 19.7 |        
    1463 | 2024-12-09 05:59:37 |         MASTER-OAFA | (10h 21m 20.55s , +06d 19m 42.7s) |   C |    60 | 19.7 |        
    1523 | 2024-12-09 05:59:37 |         MASTER-OAFA | (10h 21m 20.56s , +06d 19m 42.7s) |   C |   180 | 20.4 |  Coadd 
    1529 | 2024-12-09 06:00:42 |         MASTER-OAFA | (10h 21m 20.62s , +06d 19m 46.0s) |   C |    60 | 19.8 |        
    1645 | 2024-12-09 06:01:48 |         MASTER-OAFA | (10h 12m 17.16s , +05d 55m 36.8s) |   C |   160 | 19.3 |        
    1595 | 2024-12-09 06:01:49 |         MASTER-OAFA | (10h 21m 20.71s , +06d 19m 49.3s) |   C |    60 | 19.8 |        
    1661 | 2024-12-09 06:02:54 |         MASTER-OAFA | (10h 21m 20.76s , +06d 19m 52.3s) |   C |    60 | 19.8 |        
    1721 | 2024-12-09 06:02:54 |         MASTER-OAFA | (10h 21m 20.76s , +06d 19m 52.4s) |   C |   180 | 20.4 |  Coadd 
    1726 | 2024-12-09 06:04:00 |         MASTER-OAFA | (10h 21m 20.82s , +06d 19m 55.4s) |   C |    60 | 19.7 |        
    1842 | 2024-12-09 06:05:05 |         MASTER-OAFA | (10h 12m 17.30s , +05d 55m 45.6s) |   C |   160 | 19.3 |        
    1792 | 2024-12-09 06:05:06 |         MASTER-OAFA | (10h 21m 20.88s , +06d 19m 58.6s) |   C |    60 | 19.8 |        
    1858 | 2024-12-09 06:06:12 |         MASTER-OAFA | (10h 21m 20.95s , +06d 20m 02.1s) |   C |    60 | 19.8 |        
    1918 | 2024-12-09 06:06:12 |         MASTER-OAFA | (10h 21m 20.95s , +06d 20m 02.1s) |   C |   180 | 20.4 |  Coadd 
    1924 | 2024-12-09 06:07:17 |         MASTER-OAFA | (10h 21m 20.99s , +06d 20m 05.5s) |   C |    60 | 19.9 |        
    2039 | 2024-12-09 06:08:23 |         MASTER-OAFA | (10h 12m 17.41s , +05d 55m 55.4s) |   C |   160 | 19.3 |        
    2199 | 2024-12-09 06:08:23 |         MASTER-OAFA | (10h 12m 17.41s , +05d 55m 55.5s) |   C |   480 | 20.1 |  Coadd 
    1990 | 2024-12-09 06:08:23 |         MASTER-OAFA | (10h 21m 21.00s , +06d 20m 08.4s) |   C |    60 | 19.9 |        
    2055 | 2024-12-09 06:09:29 |         MASTER-OAFA | (10h 21m 21.03s , +06d 20m 11.5s) |   C |    60 | 20.0 |        
    2115 | 2024-12-09 06:09:29 |         MASTER-OAFA | (10h 21m 21.03s , +06d 20m 11.5s) |   C |   180 | 20.4 |  Coadd 
    2121 | 2024-12-09 06:10:35 |         MASTER-OAFA | (10h 21m 21.05s , +06d 20m 14.2s) |   C |    60 | 19.9 |        
    2237 | 2024-12-09 06:11:41 |         MASTER-OAFA | (10h 12m 17.33s , +05d 56m 04.6s) |   C |   160 | 19.4 |        
    2187 | 2024-12-09 06:11:41 |         MASTER-OAFA | (10h 21m 21.09s , +06d 20m 17.1s) |   C |    60 | 20.0 |        
    2253 | 2024-12-09 06:12:46 |         MASTER-OAFA | (10h 21m 21.11s , +06d 20m 19.7s) |   C |    60 | 20.0 |        
    2313 | 2024-12-09 06:12:46 |         MASTER-OAFA | (10h 21m 21.11s , +06d 20m 19.8s) |   C |   180 | 20.5 |  Coadd 
    2318 | 2024-12-09 06:13:52 |         MASTER-OAFA | (10h 21m 21.17s , +06d 20m 22.6s) |   C |    60 | 19.9 |        
    2435 | 2024-12-09 06:14:58 |         MASTER-OAFA | (10h 12m 17.20s , +05d 56m 13.0s) |   C |   160 | 19.4 |        
    2385 | 2024-12-09 06:14:59 |         MASTER-OAFA | (10h 21m 21.20s , +06d 20m 25.4s) |   C |    60 | 19.9 |        
    2451 | 2024-12-09 06:16:04 |         MASTER-OAFA | (10h 21m 21.22s , +06d 20m 27.9s) |   C |    60 | 20.0 |        
    2511 | 2024-12-09 06:16:04 |         MASTER-OAFA | (10h 21m 21.23s , +06d 20m 27.9s) |   C |   180 | 20.5 |  Coadd 
    2516 | 2024-12-09 06:17:10 |         MASTER-OAFA | (10h 21m 21.22s , +06d 20m 30.6s) |   C |    60 | 20.0 |        
    2632 | 2024-12-09 06:18:16 |         MASTER-OAFA | (10h 12m 17.18s , +05d 56m 21.4s) |   C |   160 | 19.3 |        
    2792 | 2024-12-09 06:18:16 |         MASTER-OAFA | (10h 12m 17.18s , +05d 56m 21.4s) |   C |   480 | 20.1 |  Coadd 
    2583 | 2024-12-09 06:18:16 |         MASTER-OAFA | (10h 21m 21.24s , +06d 20m 33.3s) |   C |    60 | 20.0 |        
    2648 | 2024-12-09 06:19:22 |         MASTER-OAFA | (10h 21m 21.27s , +06d 20m 36.1s) |   C |    60 | 20.0 |        
    2708 | 2024-12-09 06:19:22 |         MASTER-OAFA | (10h 21m 21.27s , +06d 20m 36.1s) |   C |   180 | 20.5 |  Coadd 
    2714 | 2024-12-09 06:20:28 |         MASTER-OAFA | (10h 21m 21.27s , +06d 20m 38.8s) |   C |    60 | 20.0 |        
    2831 | 2024-12-09 06:21:34 |         MASTER-OAFA | (10h 12m 17.17s , +05d 56m 30.2s) |   C |   160 | 19.4 |        
    2781 | 2024-12-09 06:21:35 |         MASTER-OAFA | (10h 21m 21.26s , +06d 20m 41.7s) |   C |    60 | 19.9 |        
    2847 | 2024-12-09 06:22:40 |         MASTER-OAFA | (10h 21m 21.27s , +06d 20m 44.1s) |   C |    60 | 20.0 |        
    2907 | 2024-12-09 06:22:40 |         MASTER-OAFA | (10h 21m 21.27s , +06d 20m 44.1s) |   C |   180 | 20.4 |  Coadd 
    2912 | 2024-12-09 06:23:46 |         MASTER-OAFA | (10h 21m 21.27s , +06d 20m 46.5s) |   C |    60 | 19.9 |        
    3028 | 2024-12-09 06:24:51 |         MASTER-OAFA | (10h 12m 17.04s , +05d 56m 36.2s) |   C |   160 | 19.4 |        
    2978 | 2024-12-09 06:24:52 |         MASTER-OAFA | (10h 21m 21.24s , +06d 20m 48.4s) |   C |    60 | 20.0 |        
    3044 | 2024-12-09 06:25:57 |         MASTER-OAFA | (10h 21m 21.24s , +06d 20m 50.9s) |   C |    60 | 20.0 |        
    3104 | 2024-12-09 06:25:57 |         MASTER-OAFA | (10h 21m 21.24s , +06d 20m 50.9s) |   C |   180 | 20.5 |  Coadd 
    3109 | 2024-12-09 06:27:03 |         MASTER-OAFA | (10h 21m 21.21s , +06d 20m 53.3s) |   C |    60 | 20.0 |        
    3225 | 2024-12-09 06:28:09 |         MASTER-OAFA | (10h 12m 16.89s , +05d 56m 41.5s) |   C |   160 | 19.5 |        
    3385 | 2024-12-09 06:28:09 |         MASTER-OAFA | (10h 12m 16.89s , +05d 56m 41.5s) |   C |   480 | 20.2 |  Coadd 
    3176 | 2024-12-09 06:28:09 |         MASTER-OAFA | (10h 21m 21.19s , +06d 20m 55.3s) |   C |    60 | 19.9 |        
    3241 | 2024-12-09 06:29:15 |         MASTER-OAFA | (10h 21m 21.19s , +06d 20m 57.8s) |   C |    60 | 20.0 |        
    3301 | 2024-12-09 06:29:15 |         MASTER-OAFA | (10h 21m 21.19s , +06d 20m 57.8s) |   C |   180 | 20.5 |  Coadd 
    3307 | 2024-12-09 06:30:21 |         MASTER-OAFA | (10h 21m 21.15s , +06d 20m 59.8s) |   C |    60 | 20.0 |        
    3424 | 2024-12-09 06:31:27 |         MASTER-OAFA | (10h 12m 16.73s , +05d 56m 45.0s) |   C |   160 | 19.5 |        
    3374 | 2024-12-09 06:31:28 |         MASTER-OAFA | (10h 21m 21.15s , +06d 21m 02.1s) |   C |    60 | 20.0 |        
    3439 | 2024-12-09 06:32:33 |         MASTER-OAFA | (10h 21m 21.13s , +06d 21m 04.3s) |   C |    60 | 20.0 |        
    3499 | 2024-12-09 06:32:33 |         MASTER-OAFA | (10h 21m 21.13s , +06d 21m 04.2s) |   C |   180 | 20.5 |  Coadd 
    3505 | 2024-12-09 06:33:39 |         MASTER-OAFA | (10h 21m 21.11s , +06d 21m 06.4s) |   C |    60 | 20.0 |        
    3621 | 2024-12-09 06:34:45 |         MASTER-OAFA | (10h 12m 16.60s , +05d 56m 49.0s) |   C |   160 | 19.4 |        
    3571 | 2024-12-09 06:34:45 |         MASTER-OAFA | (10h 21m 21.08s , +06d 21m 08.3s) |   C |    60 | 19.9 |        
    3637 | 2024-12-09 06:35:50 |         MASTER-OAFA | (10h 21m 21.06s , +06d 21m 10.4s) |   C |    60 | 20.0 |        
    3697 | 2024-12-09 06:35:50 |         MASTER-OAFA | (10h 21m 21.06s , +06d 21m 10.4s) |   C |   180 | 20.4 |  Coadd 
    3702 | 2024-12-09 06:36:56 |         MASTER-OAFA | (10h 21m 21.04s , +06d 21m 12.5s) |   C |    60 | 19.9 |        
    3818 | 2024-12-09 06:38:02 |         MASTER-OAFA | (10h 12m 16.53s , +05d 56m 56.1s) |   C |   160 | 19.4 |        
    3978 | 2024-12-09 06:38:02 |         MASTER-OAFA | (10h 12m 16.53s , +05d 56m 56.1s) |   C |   480 | 20.1 |  Coadd 
    3769 | 2024-12-09 06:38:02 |         MASTER-OAFA | (10h 21m 21.03s , +06d 21m 14.5s) |   C |    60 | 19.9 |        
    3834 | 2024-12-09 06:39:08 |         MASTER-OAFA | (10h 21m 20.97s , +06d 21m 16.4s) |   C |    60 | 19.9 |        
    3894 | 2024-12-09 06:39:08 |         MASTER-OAFA | (10h 21m 20.98s , +06d 21m 16.4s) |   C |   180 | 20.4 |  Coadd 
    3900 | 2024-12-09 06:40:14 |         MASTER-OAFA | (10h 21m 20.91s , +06d 21m 17.7s) |   C |    60 | 20.0 |        
    4016 | 2024-12-09 06:41:20 |         MASTER-OAFA | (10h 12m 16.37s , +05d 57m 02.2s) |   C |   160 | 19.3 |        
    3967 | 2024-12-09 06:41:20 |         MASTER-OAFA | (10h 21m 20.85s , +06d 21m 19.6s) |   C |    60 | 20.0 |        
    4032 | 2024-12-09 06:42:26 |         MASTER-OAFA | (10h 21m 20.83s , +06d 21m 21.6s) |   C |    60 | 20.0 |        
    4092 | 2024-12-09 06:42:26 |         MASTER-OAFA | (10h 21m 20.83s , +06d 21m 21.6s) |   C |   180 | 20.5 |  Coadd 
    4098 | 2024-12-09 06:43:32 |         MASTER-OAFA | (10h 21m 20.82s , +06d 21m 23.6s) |   C |    60 | 19.9 |        
    4214 | 2024-12-09 06:44:38 |         MASTER-OAFA | (10h 12m 16.18s , +05d 57m 08.8s) |   C |   160 | 19.5 |        
    4164 | 2024-12-09 06:44:38 |         MASTER-OAFA | (10h 21m 20.71s , +06d 21m 25.2s) |   C |    60 | 20.0 |        
    4230 | 2024-12-09 06:45:44 |         MASTER-OAFA | (10h 21m 20.63s , +06d 21m 26.5s) |   C |    60 | 20.0 |        
    4290 | 2024-12-09 06:45:44 |         MASTER-OAFA | (10h 21m 20.63s , +06d 21m 26.5s) |   C |   180 | 20.5 |  Coadd 
    4296 | 2024-12-09 06:46:49 |         MASTER-OAFA | (10h 21m 20.56s , +06d 21m 28.1s) |   C |    60 | 20.0 |        
    4413 | 2024-12-09 06:47:56 |         MASTER-OAFA | (10h 12m 15.80s , +05d 57m 12.0s) |   C |   160 | 19.6 |        
    4363 | 2024-12-09 06:47:57 |         MASTER-OAFA | (10h 21m 20.49s , +06d 21m 29.4s) |   C |    60 | 20.1 |        
    4428 | 2024-12-09 06:49:02 |         MASTER-OAFA | (10h 21m 20.43s , +06d 21m 30.6s) |   C |    60 | 20.1 |        
    4494 | 2024-12-09 06:50:07 |         MASTER-OAFA | (10h 21m 20.39s , +06d 21m 32.0s) |   C |    60 | 20.1 |        
    4609 | 2024-12-09 06:51:13 |         MASTER-OAFA | (10h 12m 15.46s , +05d 57m 15.4s) |   C |   160 | 19.5 |        
    4560 | 2024-12-09 06:51:14 |         MASTER-OAFA | (10h 21m 20.33s , +06d 21m 33.0s) |   C |    60 | 20.1 |        
    4625 | 2024-12-09 06:52:19 |         MASTER-OAFA | (10h 21m 20.26s , +06d 21m 34.3s) |   C |    60 | 20.1 |        
    4691 | 2024-12-09 06:53:25 |         MASTER-OAFA | (10h 21m 20.19s , +06d 21m 35.8s) |   C |    60 | 20.0 |        
    4808 | 2024-12-09 06:54:32 |         MASTER-OAFA | (10h 12m 15.16s , +05d 57m 19.8s) |   C |   160 | 19.6 |        
    4759 | 2024-12-09 06:54:32 |         MASTER-OAFA | (10h 21m 20.11s , +06d 21m 36.5s) |   C |    60 | 20.1 |        
    4824 | 2024-12-09 06:55:38 |         MASTER-OAFA | (10h 21m 20.04s , +06d 21m 38.1s) |   C |    60 | 20.1 |        
    4889 | 2024-12-09 06:56:43 |         MASTER-OAFA | (10h 21m 19.95s , +06d 21m 39.2s) |   C |    60 | 20.1 |        
    5005 | 2024-12-09 06:57:49 |         MASTER-OAFA | (10h 12m 14.77s , +05d 57m 23.3s) |   C |   160 | 19.5 |        
    4956 | 2024-12-09 06:57:49 |         MASTER-OAFA | (10h 21m 19.88s , +06d 21m 40.2s) |   C |    60 | 20.1 |        
    5021 | 2024-12-09 06:58:55 |         MASTER-OAFA | (10h 21m 19.79s , +06d 21m 41.4s) |   C |    60 | 20.1 |        
    5087 | 2024-12-09 07:00:01 |         MASTER-OAFA | (10h 21m 19.69s , +06d 21m 42.2s) |   C |    60 | 20.1 |        
    5203 | 2024-12-09 07:01:07 |         MASTER-OAFA | (10h 12m 14.45s , +05d 57m 26.9s) |   C |   160 | 19.7 |        
    5154 | 2024-12-09 07:01:07 |         MASTER-OAFA | (10h 21m 19.63s , +06d 21m 43.4s) |   C |    60 | 20.1 |        
    5219 | 2024-12-09 07:02:13 |         MASTER-OAFA | (10h 21m 19.54s , +06d 21m 44.2s) |   C |    60 | 20.1 |        
    5284 | 2024-12-09 07:03:18 |         MASTER-OAFA | (10h 21m 19.44s , +06d 21m 45.5s) |   C |    60 | 20.0 |        
    5400 | 2024-12-09 07:04:24 |         MASTER-OAFA | (10h 12m 14.16s , +05d 57m 29.1s) |   C |   160 | 19.6 |        
    5350 | 2024-12-09 07:04:24 |         MASTER-OAFA | (10h 21m 19.37s , +06d 21m 46.0s) |   C |    60 | 20.1 |        
    5416 | 2024-12-09 07:05:30 |         MASTER-OAFA | (10h 21m 19.26s , +06d 21m 46.5s) |   C |    60 | 20.1 |        
    5482 | 2024-12-09 07:06:35 |         MASTER-OAFA | (10h 21m 19.17s , +06d 21m 47.4s) |   C |    60 | 20.1 |        
    5598 | 2024-12-09 07:07:41 |         MASTER-OAFA | (10h 12m 13.77s , +05d 57m 30.4s) |   C |   160 | 19.7 |        
    5548 | 2024-12-09 07:07:42 |         MASTER-OAFA | (10h 21m 19.08s , +06d 21m 48.2s) |   C |    60 | 20.1 |        
    5614 | 2024-12-09 07:08:47 |         MASTER-OAFA | (10h 21m 18.98s , +06d 21m 48.5s) |   C |    60 | 20.1 |        
    5679 | 2024-12-09 07:09:53 |         MASTER-OAFA | (10h 21m 18.88s , +06d 21m 49.0s) |   C |    60 | 20.2 |        
    5795 | 2024-12-09 07:10:59 |         MASTER-OAFA | (10h 12m 13.42s , +05d 57m 33.2s) |   C |   160 | 19.8 |        
    5745 | 2024-12-09 07:10:59 |         MASTER-OAFA | (10h 21m 18.75s , +06d 21m 50.0s) |   C |    60 | 20.1 |        
    5811 | 2024-12-09 07:12:05 |         MASTER-OAFA | (10h 21m 18.64s , +06d 21m 50.3s) |   C |    60 | 20.2 |        
    5877 | 2024-12-09 07:13:10 |         MASTER-OAFA | (10h 21m 18.52s , +06d 21m 50.7s) |   C |    60 | 20.1 |        
    5993 | 2024-12-09 07:14:16 |         MASTER-OAFA | (10h 12m 13.00s , +05d 57m 34.1s) |   C |   160 | 19.6 |        
    5943 | 2024-12-09 07:14:17 |         MASTER-OAFA | (10h 21m 18.37s , +06d 21m 51.2s) |   C |    60 | 20.1 |        
    6009 | 2024-12-09 07:15:22 |         MASTER-OAFA | (10h 21m 18.27s , +06d 21m 51.4s) |   C |    60 | 20.1 |        
    6074 | 2024-12-09 07:16:28 |         MASTER-OAFA | (10h 21m 18.14s , +06d 21m 51.6s) |   C |    60 | 20.1 |        
    6190 | 2024-12-09 07:17:34 |         MASTER-OAFA | (10h 12m 12.56s , +05d 57m 34.4s) |   C |   160 | 19.7 |        
    6141 | 2024-12-09 07:17:34 |         MASTER-OAFA | (10h 21m 18.02s , +06d 21m 51.9s) |   C |    60 | 20.1 |        
    6206 | 2024-12-09 07:18:40 |         MASTER-OAFA | (10h 21m 17.89s , +06d 21m 52.0s) |   C |    60 | 20.2 |        
    6272 | 2024-12-09 07:19:46 |         MASTER-OAFA | (10h 21m 17.76s , +06d 21m 52.5s) |   C |    60 | 20.2 |        
    6388 | 2024-12-09 07:20:52 |         MASTER-OAFA | (10h 12m 12.15s , +05d 57m 34.7s) |   C |   160 | 19.7 |        
    6339 | 2024-12-09 07:20:52 |         MASTER-OAFA | (10h 21m 17.65s , +06d 21m 52.7s) |   C |    60 | 20.2 |        
    6404 | 2024-12-09 07:21:58 |         MASTER-OAFA | (10h 21m 17.50s , +06d 21m 52.9s) |   C |    60 | 20.1 |        
    6469 | 2024-12-09 07:23:03 |         MASTER-OAFA | (10h 21m 17.37s , +06d 21m 52.9s) |   C |    60 | 20.2 |        
    6585 | 2024-12-09 07:24:09 |         MASTER-OAFA | (10h 12m 11.70s , +05d 57m 35.2s) |   C |   160 | 19.7 |        
    6536 | 2024-12-09 07:24:09 |         MASTER-OAFA | (10h 21m 17.23s , +06d 21m 52.8s) |   C |    60 | 20.2 |        
    6602 | 2024-12-09 07:25:15 |         MASTER-OAFA | (10h 21m 17.10s , +06d 21m 53.1s) |   C |    60 | 20.2 |        
    6667 | 2024-12-09 07:26:21 |         MASTER-OAFA | (10h 21m 16.95s , +06d 21m 52.9s) |   C |    60 | 20.1 |        
    6783 | 2024-12-09 07:27:27 |         MASTER-OAFA | (10h 12m 11.19s , +05d 57m 34.1s) |   C |   160 | 19.7 |        
    6733 | 2024-12-09 07:27:27 |         MASTER-OAFA | (10h 21m 16.80s , +06d 21m 53.0s) |   C |    60 | 20.2 |        
    6799 | 2024-12-09 07:28:33 |         MASTER-OAFA | (10h 21m 16.68s , +06d 21m 52.7s) |   C |    60 | 20.1 |        
    6864 | 2024-12-09 07:29:38 |         MASTER-OAFA | (10h 21m 16.52s , +06d 21m 52.6s) |   C |    60 | 20.2 |        
    6980 | 2024-12-09 07:30:44 |         MASTER-OAFA | (10h 12m 10.67s , +05d 57m 32.5s) |   C |   160 | 19.7 |        
    6931 | 2024-12-09 07:30:44 |         MASTER-OAFA | (10h 21m 16.36s , +06d 21m 52.2s) |   C |    60 | 20.2 |        
    6996 | 2024-12-09 07:31:50 |         MASTER-OAFA | (10h 21m 16.23s , +06d 21m 52.1s) |   C |    60 | 20.2 |        
    7062 | 2024-12-09 07:32:55 |         MASTER-OAFA | (10h 21m 16.08s , +06d 21m 51.4s) |   C |    60 | 20.1 |        
    7178 | 2024-12-09 07:34:01 |         MASTER-OAFA | (10h 12m 10.05s , +05d 57m 30.1s) |   C |   160 | 19.5 |        
    7128 | 2024-12-09 07:34:02 |         MASTER-OAFA | (10h 21m 15.89s , +06d 21m 51.3s) |   C |    60 | 20.1 |        
    7194 | 2024-12-09 07:35:07 |         MASTER-OAFA | (10h 21m 15.73s , +06d 21m 50.5s) |   C |    60 | 20.2 |        
    7259 | 2024-12-09 07:36:13 |         MASTER-OAFA | (10h 21m 15.58s , +06d 21m 50.3s) |   C |    60 | 20.2 |        
    7375 | 2024-12-09 07:37:19 |         MASTER-OAFA | (10h 12m 09.51s , +05d 57m 27.2s) |   C |   160 | 19.7 |        
    7326 | 2024-12-09 07:37:19 |         MASTER-OAFA | (10h 21m 15.42s , +06d 21m 49.4s) |   C |    60 | 20.1 |        
    7391 | 2024-12-09 07:38:25 |         MASTER-OAFA | (10h 21m 15.28s , +06d 21m 49.2s) |   C |    60 | 20.1 |        
    7456 | 2024-12-09 07:39:30 |         MASTER-OAFA | (10h 21m 15.11s , +06d 21m 48.3s) |   C |    60 | 20.1 |        
    7572 | 2024-12-09 07:40:35 |         MASTER-OAFA | (10h 12m 08.99s , +05d 57m 26.3s) |   C |   160 | 19.7 |        
    7522 | 2024-12-09 07:40:36 |         MASTER-OAFA | (10h 21m 14.90s , +06d 21m 47.7s) |   C |    60 | 20.1 |        
    7588 | 2024-12-09 07:41:42 |         MASTER-OAFA | (10h 21m 14.72s , +06d 21m 46.9s) |   C |    60 | 20.2 |        
    7654 | 2024-12-09 07:42:47 |         MASTER-OAFA | (10h 21m 14.55s , +06d 21m 45.9s) |   C |    60 | 20.2 |        
    7770 | 2024-12-09 07:43:54 |         MASTER-OAFA | (10h 12m 08.32s , +05d 57m 22.9s) |   C |   160 | 19.5 |        
    7720 | 2024-12-09 07:43:54 |         MASTER-OAFA | (10h 21m 14.37s , +06d 21m 44.7s) |   C |    60 | 20.3 |        
    7786 | 2024-12-09 07:44:59 |         MASTER-OAFA | (10h 21m 14.19s , +06d 21m 44.3s) |   C |    60 | 20.2 |        
    7851 | 2024-12-09 07:46:05 |         MASTER-OAFA | (10h 21m 14.02s , +06d 21m 43.2s) |   C |    60 | 20.2 |        
    7967 | 2024-12-09 07:47:10 |         MASTER-OAFA | (10h 12m 07.67s , +05d 57m 19.7s) |   C |   160 | 19.8 |        
    7917 | 2024-12-09 07:47:11 |         MASTER-OAFA | (10h 21m 13.83s , +06d 21m 41.7s) |   C |    60 | 20.2 |        
    7983 | 2024-12-09 07:48:16 |         MASTER-OAFA | (10h 21m 13.64s , +06d 21m 40.5s) |   C |    60 | 20.2 |        
    8048 | 2024-12-09 07:49:22 |         MASTER-OAFA | (10h 21m 13.44s , +06d 21m 39.4s) |   C |    60 | 20.2 |        
    8164 | 2024-12-09 07:50:28 |         MASTER-OAFA | (10h 12m 07.02s , +05d 57m 16.7s) |   C |   160 | 19.6 |        
    8115 | 2024-12-09 07:50:28 |         MASTER-OAFA | (10h 21m 13.25s , +06d 21m 38.2s) |   C |    60 | 20.2 |        
    8180 | 2024-12-09 07:51:34 |         MASTER-OAFA | (10h 21m 13.04s , +06d 21m 37.2s) |   C |    60 | 20.2 |        
    8246 | 2024-12-09 07:52:39 |         MASTER-OAFA | (10h 21m 12.85s , +06d 21m 36.3s) |   C |    60 | 20.1 |        
    8362 | 2024-12-09 07:53:45 |         MASTER-OAFA | (10h 12m 06.36s , +05d 57m 11.8s) |   C |   160 | 19.5 |        
    8312 | 2024-12-09 07:53:46 |         MASTER-OAFA | (10h 21m 12.64s , +06d 21m 34.9s) |   C |    60 | 20.2 |        
    8377 | 2024-12-09 07:54:51 |         MASTER-OAFA | (10h 21m 12.45s , +06d 21m 33.3s) |   C |    60 | 20.2 |

Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.

GCN Circular #38484
A. de Ugarte Postigo (OCA and LAM), N. Habeeb (Leicester), D. B. Malesani (DAWN/NBI and Radboud Univ.), D. Xu (NAOC), L. Izzo (INAF/OACN and DARK/NBI), A. Kumar (Warwick), G. Pugliese (UvA), report on behalf of the Stargate collaboration:
We observed the field of the short GRB 241209A (Parsotan et al., GCN 38476; Fermi GBM team, GCN 38474) using the ESO/VLT equipped with the FORS2 camera and the R filter. Observations started on 2024 9.264 UT (0.77 hr after the BAT trigger).
Consistent with the location of the XRT counterpart (Page & Evans, GCN 38479) we detect an faint object at coordinates (J2000):
```
RA = 10:21:35.22
Dec = +6:19:43.3
```
From a preliminary analysis, we measure a magnitude r = 23.80+/-0.09 (AB), calibrated against nearby sources from the Legacy Survey.
This object is faintly visible in the Legacy Survey images of this field. From those images, we measure a magnitude r ~ 23.95 +- 0.15 (AB) (though we note that the magnitude reported in the Legacy Survey catalog is significantly fainter). At the current time, we cannot thus confirm the presence of transient emission in our data. Further observations are planned to establish fading.
The underlying source might be the GRB host galaxy, or unrelated to the event. We also note the presence of a brighter galaxy (r = 21.6), about 2.9" to the NW, which has a photometric redshift of 0.78 +- 0.08 in the Legacy Survey (Zhou et al. 2021, MNRAS, 501, 3309).
We acknowledge helpful support from the observing staff in Paranal, in particular Jonathan Smoker.
GCN Circular #38486
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 1321 s of XRT Photon Counting mode data and 2 UVOT images for GRB 241209A, 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 = 155.39648, +6.32872 which is equivalent to:
```
RA (J2000): 10h 21m 35.15s
Dec (J2000): +06d 19' 43.4"
```
with an uncertainty of 2.2 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 #38487
A. Saccardi (CEA/Irfu), S. D. Vergani (GEPI/Obs. de Paris), J. T. Palmerio (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud Univ.), N. Habeeb (Leicester), A. de Ugarte Postigo (OCA and LAM) report on behalf of the Stargate collaboration:
We performed ESO VLT/X-shooter spectroscopic observations of the VLT/FORS2 candidate counterpart (de Ugarte Postigo et al., GCN 38484) of GRB 241209A (Fermi GBM team, GCN 38474; Parsotan et al., GCN 38476). Our spectra cover the wavelength range 3000-25000 AA, and consist of 4 exposures of 600 s each. The observation mid-time was 2024 Dec 9.302 UT (1.66 hr after the GRB).
From a preliminary reduction of the spectra, we do not detect any continuum. Emission lines are detected in the visible and near-infrared arms, which we identify as Halpha, [OIII] 5007 AA and the [OII] 3726, 3729 AA doublet at a common redshift of z = 1.490. No absorption lines are identified due to the faintness of the source (de Ugarte Postigo et al., GCN 38484) and the low S/N of the spectra.
We notice that the recently released UVOT-enhanced X-ray position (Evans et al., GCN 38486) encompasses both this object and the brighter galaxy mentioned by de Ugarte Postigo et al. (GCN 38484), making it unclear which one, if any, is the GRB counterpart. The brighter galaxy has of course a smaller chance association probability.
We encourage further photometric observation to detect the variability of any of these two sources.
We acknowledge the excellent support from the ESO staff in Paranal, in particular Jonathan Smoker.
GCN Circular #38492
R.Brivio, M. Ferro, P. D’Avanzo, S. Covino, Y.-D. Hu, D. Fugazza (INAF-OAB) report on behalf of the REM team:
We observed the field of GRB 241209A detected by Swift/BAT (Parsotan et al., GCN 38476) and Fermi/GBM (Fermi GBM team, GCN 38474) 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 09 at 05:40:01 UT (i.e. 4.3 minutes after the Swift trigger), and lasting for about 2 hours.
From preliminary photometry we do not detect any clear counterpart in the optical and NIR images at the Swift-XRT refined position (Evans et al., GCN 38486) down to the following 3sigma magnitude upper limits:
```
r > 19.5 (AB; calibrated against the PanSTARRS catalogue)
at a mid-time of t - t0 = 67.13 minutes after the trigger,

J > 18.0
H > 16.1 (Vega; calibrated against the 2MASS catalogue)
at a mid-time of t - t0 = 42.1 and 29.8 minutes after the trigger, respectively.
```
GCN Circular #38500
M. Pillas (ULiege), S. Antier (OCA), O. Pyshna (Caltech), N. Guessoum (AUS), A. Klotz (IRAP), C. Andrade (UMN), M. Boer, C. Limonta (OCA), S. Karpov (FZU), M. Coughlin (UMN), , P. Hello (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/IPHC), D.Turpin (CEA-Saclay/Irfu), on behalf of the GRANDMA collaboration:
We observed the field of GRB 241209A, detected by Fermi/GBM (GCN 38474) and SWIFT/BAT (GCN 38476) using TAROT,/TCA and TCH. Observations began 3.5 min after Swift/T0 for TCA and 3.7 minutes after the trigger for TCH and both without a filter and continue up to 180 min after T0.
Weather was not great at TCA with an upper limit of 16 mag in r-mag of the image.
We did not detect any optical afterglow candidate with TCH to an upper limit of 19 mag in r and from T0+3 min to T0+6.1min within a circle of 6 arcmin radius centered on the most updated Swift/XRT source location (GCN 38486). It is consistent with GOTO's report (GCN 38481) and VLT's report (GCN 38484).
All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022).
GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).
GCN Circular #38502
R. Hamburg (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 05:35:44.16 UT on 09 December 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241209A (trigger 755415349/241209233), which was also detected by Swift BAT (Parsotan et al. 2024, GCN 38476) and Swift XRT (Evans et al. 2024, GCN 38486). The Fermi GBM on-ground location is consistent with the Swift position. VLT has also performed optical observations of GRB 241209A (de Ugarte Postigo et al., GCN 38484) and measured a potential redshift of z = 1.490 (Saccardi et al. 2024, GCN 38487).
The angle from the Fermi LAT boresight is 74 degrees.
The GBM light curve consists of a single peak with a duration (T90) of about 0.1 s (50-300 keV). The time-averaged spectrum from T0-0.096 to T0+0.128 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.02 +/- 0.44 and the cutoff energy, parameterized as Epeak, is 140 +/- 25 keV.
The event fluence (10-1000 keV) in this time interval is (1.2 +/- 0.2)E-07 erg/cm^2. The 64-ms peak photon flux measured starting from T0-0.064 s in the 10-1000 keV band is 5.3 +/- 0.9 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular #38504
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 241209A detected by Swift/BAT and Fermi/GBM (GCN Circ. 38474, 38476, 38479) 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 171 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 7680 seconds of exposure, we estimate an upper limit of 23.07 mag (3-sigma). This limiting magnitude is consistent with other optical observations of GOTO (Kumar et al, GCN Circ. 38481), MASTER (Lipunov et al., GCN Circ. 38483), VLT (de Ugarte Postigo et al, GCN Circ. 38484), REM (Brivio et al., GCN Circ. 38492) and GRANDMA/TAROT (Pillas et al., GCN Circ. 38500).
We warmly thank the COLIBRI engineering team and the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir.
GCN Circular #38506
B. Schneider (LAM), N. Habeeb (U. Leicester), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. Martin-Carrillo (UCD), A. de Ugarte Postigo (OCA and LAM) and N. R. Tanvir (U. Leicester) report on behalf of the Stargate collaboration:
We observed the field of the short GRB 241209A (Parsotan et al., GCN 38476; Fermi GBM team, GCN 38474) with the ESO Very Large Telescope, equipped with the HAWK-I near-infrared camera. We obtained 12 min exposures in both the H and Ks bands, as well as an 11 min exposure in J band starting at 07:51:24 UT on 2024-12-09, i.e. 2.3 hr after the Swift trigger. The observations were obtained under excellent seeing (0.5" in the J band).
The two objects mentioned by de Ugarte Postigo et al. (GCN 38484; see also Saccardi et al., GCN 38487) are both detected in all filters.
Furthermore, in all three bands we detect a faint source overlapping the wings of the brighter galaxy mentioned by de Ugarte Postigo et al. (GCN 38484), approximately 1" SE of the galaxy nucleus. The coordinates of the source are:
```
RA(J2000) = 10:21:35.14 = 155.39642
DEC(J2000) = +06:19:44.5 = 6.32902
```
with an uncertainty of 0.5".
At the present time, we cannot state whether this source is transient or pre-existing, as we lack NIR comparison imaging of sufficient quality. Under a worse seeing, this source would be easily blended within the surrounding galaxy light. Further imaging is planned to assess fading.
A comparison of the VLT/FORS2 R-band image (seeing 1.0") reported by de Ugarte Postigo et al. (GCN 38484) with the Legacy survey r-band image reveals only a marginal (~3 sigma, or ~0.1 mag) flux excess at the location of the HAWK-I candidate. Thus, due to systematic errors arising from different PSF and filter shape, we cannot confirm the presence of this source in the FORS2 R-band image at the present time.
We acknowledge the excellent support provided by the Paranal staff, in particular Jonathan Smoker and Juan Carlos Olivares.
GCN Circular #38509
Y.-D. Hu (INAF-OAB), I. Perez-Garcia, A. J. Castro-Tirado, E. Fernandez-Garcia, S.-Y. Wu, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, G. Garcia-Segura, I. Olivares, A. Sota (IAA-CSIC), C. Perez del Pulgar, A. Castellon, S. Castillo (Univ. de Malaga), L. Hernandez-Garcia (Univ. de Valparaiso), B.-B. Zhang (Nanjing Univ.) and A. Maury (Space, San Pedro de Atacama), on behalf of a larger collaboration, report:
Following the detection of the short-duration GRB 241209A by both Fermi/GBM (Fermi Team, GCN 38474) and Swift/BAT (Parsotan et al., GCN 38476), the 0.6m BOOTES-7 robotic telescope at San Pedro de Atacama (Chile) observed the GRB location starting on Dec 9, 05:39:06 UT (202 s after trigger) in different optical bands. No new optical source is detected on the co-added images (10x30s, clear-filter) at the position of the proposed near-IR counterpart candidate (Schneider et al. GCNC 38506; see also de Ugarte Postigo et al. CGCN 38484) down to 19.9 mag, consistent with other early-time reported limits (Kumar et al. GCNC 38481, Lipunov et al. GCNC 38483, Brivio et al., GCNC 38492, Pillas et al., GCNC 38500).
Additional observations were taken at the 2.2m CAHA telescope in Southern Spain (3x60s, starting on Dec 9, 06:03 UT, 28 min after trigger). Limiting magnitude for the resulting co-added image was 22.1 mag.
We thank the staff at Observatorio Astronomico de Calar Alto and San Pedro de Atacama celestial observations for their excellent support.
GCN Circular #38517
E. Troja (U Rome), Y. L. Wang (NAO, CAS), Y. Wang (PMO, CAS), H. L. Peng (NNU), W. D. Zhang (NAO,CAS), Y. -H. Yang (U Rome), R. L. Becerra (U Rome) report on behalf of the Einstein Probe team:
We performed a follow-up observation of the short GRB 241209A detected by Fermi/GBM (GCN 38474) and Swift/BAT (GCN 38476) with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The observation began at 2024-12-09T18:20:45 (UTC), about ~ 12.75 hours after the trigger, for a total exposure time of 4093 seconds.
At the position of the XRT counterpart (GCN 38486), we detect no new source. Assuming a photon index of 1.5 and a Galactic absorption of NH = 2E20 cm^-2, we derive an upper limit of ~3E-14 erg/cm2/s (0.5-10 keV; 90% confidence level).
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
GCN Circular #38523
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
We have analysed 4.9 ks of XRT data for GRB 241209A, from 91 s to 40.8 ks after the BAT trigger. The data comprise 42 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) 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=1.16 (+0.17, -0.16), followed by a break at T+485 s to an alpha of 8.0 (+0.0, -1.2).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.8 (+/-0.3). The best-fitting absorption column is 3.0 (+1.7, -1.4) x 10^21 cm^-2, in excess of the Galactic value of 2.1 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 3.7 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
```
Total column:	     3.0 (+1.7, -1.4) x 10^21 cm^-2
Galactic foreground: 2.1 x 10^20 cm^-2
Excess significance: 3.4 sigma
Photon index:	     1.8 (+/-0.3)
```
If the light curve continues to decay with a power-law decay index of 8.0, the count rate at T+24 hours will be 1.3 x 10^-18 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.0 x 10^-29 (6.8 x 10^-29) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01273071.
This circular is an official product of the Swift-XRT team.
GCN Circular #38535
A. de Ugarte Postigo (OCA and LAM, CNRS), D. B. Malesani (DAWN/NBI and Radboud Univ.), J. F. Agui Fernandez (CAHA), N. R. Tanvir (U. Leicester), C. C. Thoene (ASU-CAS, AbAO), N. A. Rakotondrainibe (LAM), L. Izzo (INAF-OACn & DARK/NBI), A. Martin-Carrillo (UCD), J. P. U. Fynbo (DAWN/NBI), S. Geier (GTC), G. L. Lombardi (GTC), N. Castro Rodriguez (GTC), A. Marante-Barreto (GTC), A. Cabrera Lavers (GTC) report:
The refined X-ray counterpart error region (Evans et al., GCN 38486) of the short GRB 241209A (Fermi collaboration, GCN 38474; Parson et al., GCN 38476; Cie et al., GCN 38478) includes two galaxies, which were identified in FORS2/VLT imaging (de Ugarte Postigo et al., GCN 38484). The fainter one, which was favoured by the initial X-ray localisation (Page et al., GCN 38479) has a redshift of z=1.490, as measured with X-shooter/VLT (Saccardi et al., GCN 38487). The inclusion of the brighter one within the refined X-ray error box, makes it a more likely candidate host for the GRB, because of a lower chance coincidence, as already mentioned by Saccardi et al. The candidate NIR counterpart reported by Schneider et al. (GCN 38506) also lies within the extension of the brighter galaxy. Should it be confirmed to fade, this would also favour this as the GRB host.
We obtained spectroscopy of this, brighter and more likely host galaxy candidate (located at RA = 10:21:35.09, Dec = +06:19:45.4) using OSIRIS+ mounted on the 10.4m GTC telescope, at the Roque de los Muchachos observatory, on the island of La Palma (Spain). The observation consisted of 3x900s using grism R1000R, which has a spectral coverage between 5100 and 10000Å at a resolving power of 670.
The spectrum shows continuum over the complete range and bright emission features that we identify as due to [OII], H-beta and [OIII] as well as CaII H and K absorptions at a common redshift of z = 0.784, which we identify as the redshift of the most likely host galaxy of GRB 241209A. We note that this is consistent with the Legacy Survey photometric redshift of 0.78+/- 0.08 (Zhou et al. 2021, MNRAS, 501, 3309).
GCN Circular #38538
Peter K. Blanchard and Edo Berger (Harvard) report on behalf of a larger collaboration:
We observed the short GRB 241209A (GCNs 38474, 38476) with Chandra/ACIS (Program 25500091, PI: Berger) starting at UT 2024-12-10 13:47:26 with an exposure time of 19.8 ks (mid-time of 38.4 hr post-burst). We detect a source consistent with the enhanced Swift/XRT position (GCN 38486) at the following coordinates:
```
RA (J2000): 10:21:35.207
Dec (J2000): +06:19:42.73
```
with a one sigma uncertainty of 0.3” in RA and Dec.
The X-ray source is closer (~0.6” away) to the fainter galaxy of the two identified by de Ugarte Postigo et al. (GCN 38484), which has a redshift of z=1.490 (GCN 38487). The source is ~2” away from the infrared source identified by Schneider et al. (GCN 38506).
We thank the Chandra team for rapidly scheduling these observations.
GCN Circular #38608
Tao An, Yuanqi Liu (SHAO), Jinjun Geng (PMO), and Xuefeng Wu (PMO) report on behalf of the Einstein Probe radio follow-up team:
Following the detection of GRB 241209A by Fermi and Swift (Hamburg et al. 2024, GCN 38502; Evans et al. 2024, GCN 38523), we conducted radio follow-up observations using the Australia Telescope Compact Array (ATCA). We observed the VLT position [RA(J2000) = 10:21:35.14, Dec(J2000) = +06:19:44.5] during UTC 16:00:00-22:00:00 on December 14, 2024. No significant emission was detected at either 5.5 GHz or 9 GHz, yielding 3σ upper limits of 51 microJy and 36 microJy, respectively.
We thank the ATCA team for their rapid scheduling and support.

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Jochen Greiner, last update: 18-Dec-2024 [Disclaimer]