Gamma-ray Burst 210104B

(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 04 Jan 21 21:10:23 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1015919,   Seg_Num: 0
GRB_RA:           53.601d {+03h 34m 24s} (J2000),
                  53.944d {+03h 35m 47s} (current),
                  52.787d {+03h 31m 09s} (1950)
GRB_DEC:         +37.931d {+37d 55' 51"} (J2000),
                 +38.000d {+37d 59' 60"} (current),
                 +37.764d {+37d 45' 50"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       3485 [cnts]    Image_Peak=159 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   137     E_range: 15-50 keV
BKG_INTEN:       22116 [cnts]
BKG_TIME:        76197.72 SOD {21:09:57.72} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19218 TJD;     4 DOY;   21/01/04
GRB_TIME:        76210.84 SOD {21:10:10.84} UT
GRB_PHI:         -108.99 [deg]
GRB_THETA:        25.69 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.53 [sigma]
IMAGE_SIGNIF:    7.88 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +1  -2  +0  +0 +67  +0 
SUN_POSTN:       286.00d {+19h 04m 00s}  -22.62d {-22d 37' 14"}
SUN_DIST:        133.16 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.53d {+11h 50m 06s}   +6.78d {+06d 46' 47"}
MOON_DIST:       111.11 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.06,-14.57 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       60.49, 18.15 [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 = 39.59,15.46 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 21 21:11:37 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1015919,   Seg_Num: 0
POINT_RA:         53.619d {+03h 34m 28s} (J2000)
POINT_DEC:       +37.923d {+37d 55' 25"} (J2000)
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76291.25 SOD {21:11:31.25} UT,   80.4 [sec] since BAT Trigger Time
COUNTS:          17    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        2    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 21 21:13:53 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1015919,   Seg_Num: 0
GRB_RA:           53.601d {+03h 34m 24s} (J2000),
                  53.944d {+03h 35m 47s} (current),
                  52.787d {+03h 31m 09s} (1950)
GRB_DEC:         +37.931d {+37d 55' 51"} (J2000),
                 +38.000d {+37d 59' 60"} (current),
                 +37.764d {+37d 45' 50"} (1950)
GRB_DATE:        19218 TJD;     4 DOY;   21/01/04
GRB_TIME:        76210.84 SOD {21:10:10.84} UT
TRIGGER_INDEX:   137
GRB_PHI:         -108.99 [deg]
GRB_THETA:        25.69 [deg]
DELTA_TIME:      -31.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.53 [sigma]
IMAGE_SIGNIF:    7.88 [sigma]
LC_URL:          sw01015919000msb.lc
SUN_POSTN:       286.00d {+19h 04m 01s}  -22.62d {-22d 37' 13"}
SUN_DIST:        133.16 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.56d {+11h 50m 14s}   +6.77d {+06d 45' 58"}
MOON_DIST:       111.14 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.06,-14.57 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       60.49, 18.15 [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 = 39.59,15.46 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 21 21:14:33 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1015919,   Seg_Num: 0
POINT_RA:         53.619d {+03h 34m 29s} (J2000)
POINT_DEC:       +37.923d {+37d 55' 22"} (J2000)
POINT_ROLL:      273.350d
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76294.72 SOD {21:11:34.72} UT,   83.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.842
N_STARS:         48
X_OFFSET:        608 [pixels]
Y_OFFSET:        539 [pixels]
X_MAX:           1567 [pixels]
Y_MAX:           1498 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw01015919000msufc0083.fits
SUN_POSTN:       286.00d {+19h 04m 01s}  -22.62d {-22d 37' 12"}
SUN_DIST:        133.17 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.56d {+11h 50m 15s}   +6.76d {+06d 45' 49"}
MOON_DIST:       111.14 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.08,-14.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       60.50, 18.14 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 21 21:14:43 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1015919,   Seg_Num: 0
POINT_RA:         53.619d {+03h 34m 29s} (J2000)
POINT_DEC:       +37.923d {+37d 55' 22"} (J2000)
POINT_ROLL:      273.350d
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76294.72 SOD {21:11:34.72} UT,   83.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.842
N_STARS:         48
X_OFFSET:        608 [pixels]
Y_OFFSET:        539 [pixels]
X_MAX:           1567 [pixels]
Y_MAX:           1498 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw01015919000msufc0083.fits
SUN_POSTN:       286.01d {+19h 04m 01s}  -22.62d {-22d 37' 12"}
SUN_DIST:        133.17 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.57d {+11h 50m 16s}   +6.76d {+06d 45' 46"}
MOON_DIST:       111.14 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.08,-14.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       60.50, 18.14 [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 04 Jan 21 21:16:18 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1015919,   Seg_Num: 0
POINT_RA:         53.619d {+03h 34m 29s} (J2000)
POINT_DEC:       +37.923d {+37d 55' 22"} (J2000)
ROLL:            273.350d
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76294.72 SOD {21:11:34.72} UT,   83.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     631487521
X_OFFSET:        927 [pixels]
Y_OFFSET:        858 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1087
Y_GRB_POS:       1018
BINNING_INDEX:   1
IM_URL:          sw01015919000msuni0110.fits
SUN_POSTN:       286.01d {+19h 04m 02s}  -22.62d {-22d 37' 12"}
SUN_DIST:        133.17 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.58d {+11h 50m 19s}   +6.76d {+06d 45' 24"}
MOON_DIST:       111.15 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.08,-14.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       60.50, 18.14 [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 04 Jan 21 21:15:25 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1015919,   Seg_Num: 0
GRB_RA:           53.5545d {+03h 34m 13.07s} (J2000),
                  53.8973d {+03h 35m 35.35s} (current),
                  52.7409d {+03h 30m 57.81s} (1950)
GRB_DEC:         +37.9293d {+37d 55' 45.4"} (J2000),
                 +37.9985d {+37d 59' 54.6"} (current),
                 +37.7623d {+37d 45' 44.3"} (1950)
GRB_ERROR:       4.4 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76311.00 SOD {21:11:51.00} UT,   100.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       286.01d {+19h 04m 01s}  -22.62d {-22d 37' 12"}
SUN_DIST:        133.12 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.57d {+11h 50m 17s}   +6.76d {+06d 45' 36"}
MOON_DIST:       111.19 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.04,-14.59 [deg] galactic lon,lat of the burst
ECL_COORDS:       60.45, 18.15 [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:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 21 21:16:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1015919,   Seg_Num: 0
POINT_RA:         53.619d {+03h 34m 29s} (J2000)
POINT_DEC:       +37.923d {+37d 55' 22"} (J2000)
ROLL:            273.350d
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76294.72 SOD {21:11:34.72} UT,   83.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     631487521
X_OFFSET:        927 [pixels]
Y_OFFSET:        858 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1087
Y_GRB_POS:       1018
BINNING_INDEX:   1
IM_URL:          sw01015919000msuni0110.fits
SUN_POSTN:       286.01d {+19h 04m 02s}  -22.62d {-22d 37' 12"}
SUN_DIST:        133.17 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.58d {+11h 50m 19s}   +6.76d {+06d 45' 21"}
MOON_DIST:       111.16 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.08,-14.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       60.50, 18.14 [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 04 Jan 21 21:23:26 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1015919,   Seg_Num: 0
POINT_RA:         53.622d {+03h 34m 29s} (J2000)
POINT_DEC:       +37.923d {+37d 55' 24"} (J2000)
POINT_ROLL:      273.353d
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76506.82 SOD {21:15:06.82} UT,   296.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.842
N_STARS:         47
X_OFFSET:        368 [pixels]
Y_OFFSET:        299 [pixels]
X_MAX:           1807 [pixels]
Y_MAX:           1738 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw01015919000msufc0295.fits
SUN_POSTN:       286.01d {+19h 04m 03s}  -22.62d {-22d 37' 10"}
SUN_DIST:        133.17 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.64d {+11h 50m 34s}   +6.73d {+06d 43' 44"}
MOON_DIST:       111.22 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.08,-14.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       60.51, 18.14 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 21 21:23:48 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1015919,   Seg_Num: 0
GRB_RA:           53.5538d {+03h 34m 12.91s} (J2000),
                  53.8966d {+03h 35m 35.18s} (current),
                  52.7402d {+03h 30m 57.64s} (1950)
GRB_DEC:         +37.9301d {+37d 55' 48.3"} (J2000),
                 +37.9993d {+37d 59' 57.5"} (current),
                 +37.7631d {+37d 45' 47.2"} (1950)
GRB_ERROR:       2.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76311.00 SOD {21:11:51.00} UT,   100.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       286.01d {+19h 04m 03s}  -22.62d {-22d 37' 10"}
SUN_DIST:        133.12 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.65d {+11h 50m 35s}   +6.73d {+06d 43' 38"}
MOON_DIST:       111.26 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.03,-14.59 [deg] galactic lon,lat of the burst
ECL_COORDS:       60.45, 18.16 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
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 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 21 21:23:37 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1015919,   Seg_Num: 0
POINT_RA:         53.622d {+03h 34m 29s} (J2000)
POINT_DEC:       +37.923d {+37d 55' 24"} (J2000)
POINT_ROLL:      273.353d
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76506.82 SOD {21:15:06.82} UT,   296.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.842
N_STARS:         47
X_OFFSET:        368 [pixels]
Y_OFFSET:        299 [pixels]
X_MAX:           1807 [pixels]
Y_MAX:           1738 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw01015919000msufc0295.fits
SUN_POSTN:       286.01d {+19h 04m 03s}  -22.62d {-22d 37' 10"}
SUN_DIST:        133.17 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.64d {+11h 50m 34s}   +6.73d {+06d 43' 41"}
MOON_DIST:       111.22 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.08,-14.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       60.51, 18.14 [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 04 Jan 21 21:24:49 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1015919,   Seg_Num: 0
POINT_RA:         53.622d {+03h 34m 29s} (J2000)
POINT_DEC:       +37.923d {+37d 55' 24"} (J2000)
ROLL:            273.353d
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76506.82 SOD {21:15:06.82} UT,   296.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     631487733
X_OFFSET:        927 [pixels]
Y_OFFSET:        858 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1087
Y_GRB_POS:       1018
BINNING_INDEX:   1
IM_URL:          sw01015919000msuni0322.fits
SUN_POSTN:       286.01d {+19h 04m 03s}  -22.62d {-22d 37' 10"}
SUN_DIST:        133.17 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.65d {+11h 50m 37s}   +6.72d {+06d 43' 24"}
MOON_DIST:       111.23 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.08,-14.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       60.51, 18.14 [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 04 Jan 21 21:25:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1015919,   Seg_Num: 0
POINT_RA:         53.622d {+03h 34m 29s} (J2000)
POINT_DEC:       +37.923d {+37d 55' 24"} (J2000)
ROLL:            273.353d
IMG_START_DATE:  19218 TJD;     4 DOY;   21/01/04
IMG_START_TIME:  76506.82 SOD {21:15:06.82} UT,   296.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     631487733
X_OFFSET:        927 [pixels]
Y_OFFSET:        858 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1087
Y_GRB_POS:       1018
BINNING_INDEX:   1
IM_URL:          sw01015919000msuni0322.fits
SUN_POSTN:       286.01d {+19h 04m 03s}  -22.62d {-22d 37' 09"}
SUN_DIST:        133.17 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      177.66d {+11h 50m 38s}   +6.72d {+06d 43' 21"}
MOON_DIST:       111.23 [deg]
MOON_ILLUM:      67 [%]
GAL_COORDS:      155.08,-14.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       60.51, 18.14 [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 #29243
S. Laha (GSFC/UMBC/CRESST), M. G. Bernardini (INAF-OAB), A. A. Breeveld (UCL-MSSL), P. D'Avanzo (INAF-OAB), C. Gronwall (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), M. J. Moss (GWU), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sbarrato (INAF-OAB) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 21:10:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210104B (trigger=1015919). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 53.601, +37.931 which is
```
   RA(J2000) = 03h 34m 24s
   Dec(J2000) = +37d 55' 51"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 30 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 21:11:31.2 UT, 80.5 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 53.5539, 37.9302 which is equivalent to:
```
RA(J2000)  = 03h 34m 12.93s
   Dec(J2000) = +37d 55' 48.7"
```
with an uncertainty of 2.5 arcseconds (radius, 90% containment). This location is 133 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (2.67 x 10^21 cm^-2, Willingale et al. 2013), with an excess column of 1.6 (+1.04/-0.80) x 10^22 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 83 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 none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT 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 0.79.
Burst Advocate for this burst is S. Laha (sib.laha AT gmail.com). 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 Circular #29249
Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, M.D. Caballero-Garcia (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco, A. Reina (Univ. de Malaga), F. Rendon (IAA-CSIC and INTA-CEDEA) R. Fernandez-Munoz (IHSM/UMA-CSIC) and M. Jelinek (ASU-CAS) on behalf of a larger collaboration, report:
Following the Swift trigger of GRB 210104B (Laha et al., GCNC 29243), the 0.3m BOOTES-1B robotic telescope in Mazagon (Huelva), southern Spain, automatically responded to this burst. Series images were taken started 2021-01-04 21:11:00 UT (~50 s after trigger). In the co-added of 10x10 s images, no source is detected within the XRT position (Laha et al., GCNC 29243) which down to 18.1 mag (clear filter).
The 0.6m BOOTES-2/TELMA robotic telescope at IHSM La Mayora (UMA-CSIC) in Algarrobo Costa (Malaga, Spain) also automatically responded to the Swift trigger of GRB 210104B (Laha et al., GCNC 29243). A series of images were taken starting on 2021-01-04 21:11:24 UT (~74 s after trigger). No optical source is detected within the XRT position on the co-added image (10x10 s, clear filter) which down to 19.9 mag.
Those non-detections are consistent with the reports from Swift (Laha et al., GCNC 29243) and MASTER-Net (Lipunov et al., GCNC 29242). Additional observations are ongoing. We thank the staff at INTA-CEDEA and La Mayora for their excellent support.
GCN Circular #29250
S.Y. Fu (NAOC), Z.P. Zhu (NAOC, HUST), X. Liu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 210104B (Laha et al., GCN 29243) using the NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. Observations automatically started at UT on 2020-12-21, i.e., 75 s after the BAT trigger. We obtained a series of 40 s, 60 s and 90 s frames in the Sloan r-filter.
No optical source is detected in our stacked image at the Swift/XRT position (Laha et al., GCN 29243), down to a limiting magnitude of r~21.0, calibrated with the nearby PanSTARRS field.
GCN Circular #29253
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 1436 s of XRT Photon Counting mode data and 3 UVOT images for GRB 210104B, 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 = 53.55295, +37.93051 which is equivalent to:
```
RA (J2000): 03h 34m 12.71s
Dec (J2000): +37d 55' 49.8"
```
with an uncertainty of 1.9 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 #29255
V. Kim (FAI, Pulkovo), I. Reva (FAI), M. Krugov (FAI), Y. Aimuratov (FAI) report:
We observed the field of GRB 210104B (Laha et al., GCN 29243) with AZT-20 1.5-m telescope of Assy-Turgen Observatory (Assy) starting on Jan. 04 (UT) 22:31:15. We did not find any optical counterpart in our 20x60s stacked image in the enhanced XRT position (Evans et al., GCN 29253) down to an upper limit R~23.2 (see also Hu et al., GCN 29249 and Fu et al., GCN 29250). Preliminary photometry of the filed is the following:
```
Date        UT start  t-T0         Filter  Exp.    OT    Err.  UL(3-sigma) FWHM
                       (mid, days)          (s)                              (")
2021-01-04  22:31:15  0.06325      r'      20*60   n/d   n/d   23.2         2.3
```
Further observations on this object are not planned except personal request.
GCN Circular #29256
J. D. Gropp (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), A. Tohuvavohu (U. Toronto) and S. Laha report on behalf of the Swift-XRT team:
We have analysed 6.2 ks of XRT data for GRB 210104B (Laha et al. GCN Circ. 29243), from 100 s to 39.8 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 29253).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.59 (+/-0.04).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.31 (+0.27, -0.25). The best-fitting absorption column is 1.15 (+0.26, -0.23) x 10^22 cm^-2, in excess of the Galactic value of 2.7 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.3 x 10^-11 (1.3 x 10^-10) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.15 (+0.26, -0.23) x 10^22 cm^-2
Galactic foreground: 2.7 x 10^21 cm^-2
Excess significance: 6.4 sigma
Photon index:	     2.31 (+0.27, -0.25)
```
If the light curve continues to decay with a power-law decay index of 0.59, the count rate at T+24 hours will be 0.019 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.4 x 10^-13 (2.4 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01015919.
This circular is an official product of the Swift-XRT team.
GCN Circular #29259
A. A. Breeveld (UCL-MSSL) and S. L. Laha (GSFC/UMBC/CRESST) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210104B 84 s after the BAT trigger (Laha et al., GCN Circ. 29243). No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 29253) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC            84          234          147         >20.5
u_FC               296          546          246         >19.8
white               84          753          172         >20.7
v                  625          645           19         >17.6
b                  551          743           39         >19.1
u                  296          719          265         >19.9
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.79 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #29266
T. Sakamoto (AGU), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210104B (trigger #1015919) (Laha et al., GCN Circ. 29243). The BAT ground-calculated position is RA, Dec = 53.561, 37.951 deg which is
```
   RA(J2000)  =  03h 34m 14.7s
   Dec(J2000) = +37d 57' 05.1"
```
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 59%.
The mask-weighted light curve shows a double peaks structure that starts at ~T0 and ends at ~T+23 s. The two peaks occurs at ~T0 and ~T+11 s, respectively. T90 (15-350 keV) is 19.94 +- 2.33 sec (estimated error including systematics).
The time-averaged spectrum from T-0.15 to T+22.76 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.83 +- 0.14. The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+10.83 sec in the 15-150 keV band is 1.9 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1015919/BA/

Back to JG's homepage

Jochen Greiner, last update: 06-Jan-2021 [Disclaimer]