Gamma-ray Burst 210222B

(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 22 Feb 21 22:37:59 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1034325,   Seg_Num: 0
GRB_RA:          154.621d {+10h 18m 29s} (J2000),
                 154.879d {+10h 19m 31s} (current),
                 154.013d {+10h 16m 03s} (1950)
GRB_DEC:         -14.898d {-14d 53' 52"} (J2000),
                 -15.005d {-15d 00' 15"} (current),
                 -14.647d {-14d 38' 49"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5534 [cnts]    Image_Peak=167 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   444     E_range: 15-50 keV
BKG_INTEN:       58294 [cnts]
BKG_TIME:        81413.44 SOD {22:36:53.44} UT
BKG_DUR:         24 [sec]
GRB_DATE:        19267 TJD;    53 DOY;   21/02/22
GRB_TIME:        81446.27 SOD {22:37:26.27} UT
GRB_PHI:          82.77 [deg]
GRB_THETA:        28.46 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.34 [sigma]
IMAGE_SIGNIF:    7.45 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +1  -2  +0  +0 +90  +0 
SUN_POSTN:       336.40d {+22h 25m 35s}   -9.85d {-09d 50' 48"}
SUN_DIST:        155.10 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.72d {+06h 42m 54s}  +25.03d {+25d 01' 54"}
MOON_DIST:        66.24 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.80, 33.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      162.35,-23.62 [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 = 351.11,16.70 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 22 Feb 21 22:39:07 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.635d {+10h 18m 32s} (J2000)
POINT_DEC:       -14.917d {-14d 55' 01"} (J2000)
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81542.17 SOD {22:39:02.17} UT,   95.9 [sec] since BAT Trigger Time 
COUNTS:          7    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    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 22 Feb 21 22:41:25 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1034325,   Seg_Num: 0
GRB_RA:          154.621d {+10h 18m 29s} (J2000),
                 154.879d {+10h 19m 31s} (current),
                 154.013d {+10h 16m 03s} (1950)
GRB_DEC:         -14.898d {-14d 53' 52"} (J2000),
                 -15.005d {-15d 00' 15"} (current),
                 -14.647d {-14d 38' 49"} (1950)
GRB_DATE:        19267 TJD;    53 DOY;   21/02/22
GRB_TIME:        81446.27 SOD {22:37:26.27} UT
TRIGGER_INDEX:   444
GRB_PHI:          82.77 [deg]
GRB_THETA:        28.46 [deg]
DELTA_TIME:      77.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.34 [sigma]
IMAGE_SIGNIF:    7.45 [sigma]
LC_URL:          sw01034325000msb.lc
SUN_POSTN:       336.40d {+22h 25m 35s}   -9.85d {-09d 50' 45"}
SUN_DIST:        155.10 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.76d {+06h 43m 02s}  +25.03d {+25d 01' 54"}
MOON_DIST:        66.21 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.80, 33.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      162.35,-23.62 [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 = 351.11,16.70 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 22 Feb 21 22:42:06 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.635d {+10h 18m 32s} (J2000)
POINT_DEC:       -14.918d {-14d 55' 03"} (J2000)
POINT_ROLL:      184.163d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81546.91 SOD {22:39:06.91} UT,   100.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.881
N_STARS:         190
X_OFFSET:        395 [pixels]
Y_OFFSET:        726 [pixels]
X_MAX:           1354 [pixels]
Y_MAX:           1685 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw01034325000msufc0100.fits
SUN_POSTN:       336.40d {+22h 25m 35s}   -9.85d {-09d 50' 44"}
SUN_DIST:        155.09 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.76d {+06h 43m 03s}  +25.03d {+25d 01' 54"}
MOON_DIST:        66.23 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 22 Feb 21 22:42:18 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.635d {+10h 18m 32s} (J2000)
POINT_DEC:       -14.918d {-14d 55' 03"} (J2000)
POINT_ROLL:      184.163d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81546.91 SOD {22:39:06.91} UT,   100.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.881
N_STARS:         190
X_OFFSET:        395 [pixels]
Y_OFFSET:        726 [pixels]
X_MAX:           1354 [pixels]
Y_MAX:           1685 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw01034325000msufc0100.fits
SUN_POSTN:       336.40d {+22h 25m 36s}   -9.85d {-09d 50' 44"}
SUN_DIST:        155.09 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.77d {+06h 43m 04s}  +25.03d {+25d 01' 54"}
MOON_DIST:        66.23 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [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 22 Feb 21 22:42:49 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1034325,   Seg_Num: 0
GRB_RA:          154.6071d {+10h 18m 25.70s} (J2000),
                 154.8646d {+10h 19m 27.50s} (current),
                 153.9985d {+10h 16m 00.36s} (1950)
GRB_DEC:         -14.9305d {-14d 55' 49.8"} (J2000),
                 -15.0370d {-15d 02' 13.0"} (current),
                 -14.6796d {-14d 40' 46.6"} (1950)
GRB_ERROR:       3.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81558.00 SOD {22:39:18.00} UT,   111.7 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       336.40d {+22h 25m 36s}   -9.85d {-09d 50' 43"}
SUN_DIST:        155.07 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.77d {+06h 43m 05s}  +25.03d {+25d 01' 55"}
MOON_DIST:        66.21 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.81, 33.91 [deg] galactic lon,lat of the burst
ECL_COORDS:      162.35,-23.65 [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 22 Feb 21 22:44:25 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.635d {+10h 18m 32s} (J2000)
POINT_DEC:       -14.918d {-14d 55' 03"} (J2000)
ROLL:            184.163d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81546.91 SOD {22:39:06.91} UT,   100.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     635726373
X_OFFSET:        714 [pixels]
Y_OFFSET:        1045 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       874
Y_GRB_POS:       1205
BINNING_INDEX:   1
IM_URL:          sw01034325000msuni0127.fits
SUN_POSTN:       336.40d {+22h 25m 36s}   -9.85d {-09d 50' 42"}
SUN_DIST:        155.09 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.79d {+06h 43m 09s}  +25.03d {+25d 01' 55"}
MOON_DIST:        66.21 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [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 22 Feb 21 22:44:40 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.635d {+10h 18m 32s} (J2000)
POINT_DEC:       -14.918d {-14d 55' 03"} (J2000)
ROLL:            184.163d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81546.91 SOD {22:39:06.91} UT,   100.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     635726373
X_OFFSET:        714 [pixels]
Y_OFFSET:        1045 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       874
Y_GRB_POS:       1205
BINNING_INDEX:   1
IM_URL:          sw01034325000msuni0127.fits
SUN_POSTN:       336.40d {+22h 25m 36s}   -9.85d {-09d 50' 42"}
SUN_DIST:        155.09 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.79d {+06h 43m 09s}  +25.03d {+25d 01' 55"}
MOON_DIST:        66.21 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [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 22 Feb 21 22:47:03 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     1034325,   Seg_Num: 0
GRB_RA:          154.6060d {+10h 18m 25.43s} (J2000),
                 154.8635d {+10h 19m 27.23s} (current),
                 153.9974d {+10h 15m 59.37s} (1950)
GRB_DEC:         -14.9321d {-14d 55' 55.5"} (J2000),
                 -15.0386d {-15d 02' 18.8"} (current),
                 -14.6812d {-14d 40' 52.4"} (1950)
GRB_ERROR:       1.1 [arcsec radius, statistical only]
GRB_MAG:         17.64 +/- 0.40 [mag]
FILTER:          10, White
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81543.00 SOD {22:39:03.00} UT,   96.7 [sec] since BAT Trigger Time
SUN_POSTN:       336.40d {+22h 25m 36s}   -9.84d {-09d 50' 40"}
SUN_DIST:        155.07 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.81d {+06h 43m 15s}  +25.03d {+25d 01' 55"}
MOON_DIST:        66.18 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.81, 33.90 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      162.35,-23.66 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        Result based on srclist data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 22 Feb 21 22:51:02 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.636d {+10h 18m 33s} (J2000)
POINT_DEC:       -14.920d {-14d 55' 12"} (J2000)
POINT_ROLL:      184.162d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81704.84 SOD {22:41:44.84} UT,   258.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.592
N_STARS:         187
X_OFFSET:        155 [pixels]
Y_OFFSET:        486 [pixels]
X_MAX:           1594 [pixels]
Y_MAX:           1925 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01034325000msufc0258.fits
SUN_POSTN:       336.40d {+22h 25m 37s}   -9.84d {-09d 50' 36"}
SUN_DIST:        155.08 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.85d {+06h 43m 24s}  +25.03d {+25d 01' 56"}
MOON_DIST:        66.16 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 22 Feb 21 22:52:09 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.636d {+10h 18m 33s} (J2000)
POINT_DEC:       -14.920d {-14d 55' 12"} (J2000)
ROLL:            184.162d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81704.84 SOD {22:41:44.84} UT,   258.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     635726531
X_OFFSET:        714 [pixels]
Y_OFFSET:        1045 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       874
Y_GRB_POS:       1205
BINNING_INDEX:   1
IM_URL:          sw01034325000msuni0285.fits
SUN_POSTN:       336.40d {+22h 25m 37s}   -9.84d {-09d 50' 35"}
SUN_DIST:        155.08 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.86d {+06h 43m 27s}  +25.03d {+25d 01' 56"}
MOON_DIST:        66.15 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [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 22 Feb 21 22:51:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.636d {+10h 18m 33s} (J2000)
POINT_DEC:       -14.920d {-14d 55' 12"} (J2000)
POINT_ROLL:      184.162d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81704.84 SOD {22:41:44.84} UT,   258.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.592
N_STARS:         187
X_OFFSET:        155 [pixels]
Y_OFFSET:        486 [pixels]
X_MAX:           1594 [pixels]
Y_MAX:           1925 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01034325000msufc0258.fits
SUN_POSTN:       336.40d {+22h 25m 37s}   -9.84d {-09d 50' 36"}
SUN_DIST:        155.08 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.85d {+06h 43m 25s}  +25.03d {+25d 01' 56"}
MOON_DIST:        66.16 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [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 22 Feb 21 22:52:15 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.636d {+10h 18m 33s} (J2000)
POINT_DEC:       -14.920d {-14d 55' 12"} (J2000)
ROLL:            184.162d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81704.84 SOD {22:41:44.84} UT,   258.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     635726531
X_OFFSET:        714 [pixels]
Y_OFFSET:        1045 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       874
Y_GRB_POS:       1205
BINNING_INDEX:   1
IM_URL:          sw01034325000msuni0285.fits
SUN_POSTN:       336.40d {+22h 25m 37s}   -9.84d {-09d 50' 35"}
SUN_DIST:        155.08 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.86d {+06h 43m 27s}  +25.03d {+25d 01' 56"}
MOON_DIST:        66.15 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [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 22 Feb 21 22:51:29 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1034325,   Seg_Num: 0
GRB_RA:          154.6062d {+10h 18m 25.48s} (J2000),
                 154.8637d {+10h 19m 27.28s} (current),
                 153.9976d {+10h 15m 59.42s} (1950)
GRB_DEC:         -14.9315d {-14d 55' 53.3"} (J2000),
                 -15.0380d {-15d 02' 16.6"} (current),
                 -14.6806d {-14d 40' 50.2"} (1950)
GRB_ERROR:       2.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  81558.00 SOD {22:39:18.00} UT,   111.7 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       336.40d {+22h 25m 37s}   -9.84d {-09d 50' 35"}
SUN_DIST:        155.07 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.86d {+06h 43m 25s}  +25.03d {+25d 01' 56"}
MOON_DIST:        66.14 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.81, 33.90 [deg] galactic lon,lat of the burst
ECL_COORDS:      162.35,-23.65 [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 Circular #29544
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB210222.94 (trigger No 1034325,10h 18m 29.04s , -14d 53m 52.8s, R=0.05) errorbox 235 sec after notice time and 276 sec after trigger time at 2021-02-22 22:42:03 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 17 deg. The sun altitude is -48.0 deg.
The galactic latitude b = 34 deg., longitude l = 258 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1553237
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

     367 |         MASTER-SAAO |   C |   180 | 17.9 |
```
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 22 Feb 21 22:58:26 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.636d {+10h 18m 33s} (J2000)
POINT_DEC:       -14.920d {-14d 55' 12"} (J2000)
POINT_ROLL:      184.162d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  82308.28 SOD {22:51:48.28} UT,   862.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.859
N_STARS:         190
X_OFFSET:        155 [pixels]
Y_OFFSET:        486 [pixels]
X_MAX:           1594 [pixels]
Y_MAX:           1925 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw01034325000msufc0862.fits
SUN_POSTN:       336.41d {+22h 25m 38s}   -9.84d {-09d 50' 29"}
SUN_DIST:        155.09 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.92d {+06h 43m 41s}  +25.03d {+25d 01' 57"}
MOON_DIST:        66.11 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 22 Feb 21 22:58:40 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.636d {+10h 18m 33s} (J2000)
POINT_DEC:       -14.920d {-14d 55' 12"} (J2000)
POINT_ROLL:      184.162d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  82308.28 SOD {22:51:48.28} UT,   862.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.859
N_STARS:         190
X_OFFSET:        155 [pixels]
Y_OFFSET:        486 [pixels]
X_MAX:           1594 [pixels]
Y_MAX:           1925 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw01034325000msufc0862.fits
SUN_POSTN:       336.41d {+22h 25m 38s}   -9.84d {-09d 50' 29"}
SUN_DIST:        155.09 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.93d {+06h 43m 42s}  +25.03d {+25d 01' 57"}
MOON_DIST:        66.11 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [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 22 Feb 21 22:59:55 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.636d {+10h 18m 33s} (J2000)
POINT_DEC:       -14.920d {-14d 55' 12"} (J2000)
ROLL:            184.162d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  82308.28 SOD {22:51:48.28} UT,   862.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     635727134
X_OFFSET:        714 [pixels]
Y_OFFSET:        1045 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       874
Y_GRB_POS:       1205
BINNING_INDEX:   1
IM_URL:          sw01034325000msuni0889.fits
SUN_POSTN:       336.41d {+22h 25m 38s}   -9.84d {-09d 50' 28"}
SUN_DIST:        155.09 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.94d {+06h 43m 45s}  +25.03d {+25d 01' 57"}
MOON_DIST:        66.10 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [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 22 Feb 21 23:00:08 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1034325,   Seg_Num: 0
POINT_RA:        154.636d {+10h 18m 33s} (J2000)
POINT_DEC:       -14.920d {-14d 55' 12"} (J2000)
ROLL:            184.162d
IMG_START_DATE:  19267 TJD;    53 DOY;   21/02/22
IMG_START_TIME:  82308.28 SOD {22:51:48.28} UT,   862.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     635727134
X_OFFSET:        714 [pixels]
Y_OFFSET:        1045 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       874
Y_GRB_POS:       1205
BINNING_INDEX:   1
IM_URL:          sw01034325000msuni0889.fits
SUN_POSTN:       336.41d {+22h 25m 38s}   -9.84d {-09d 50' 28"}
SUN_DIST:        155.09 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      100.94d {+06h 43m 45s}  +25.03d {+25d 01' 57"}
MOON_DIST:        66.09 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      256.83, 33.93 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      162.38,-23.63 [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 #29545
J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU), D. M. Palmer (LANL) and B. Sbarufatti (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 22:37:26 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210222B (trigger=1034325). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 154.621, -14.898 which is
```
   RA(J2000) = 10h 18m 29s
   Dec(J2000) = -14d 53' 52"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 20 sec. The peak count rate was ~1250 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 22:39:02.1 UT, 95.9 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 154.6062, -14.9316 which is equivalent to:
```
   RA(J2000)  = 10h 18m 25.50s
   Dec(J2000) = -14d 55' 53.7"
```
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 131 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.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (8.87 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3 (+1.87/-1.66) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of nominal 150.000 seconds with the White filter starting 100 seconds after the BAT trigger. There is a candidate afterglow in the list of sources generated on-board at
```
  RA(J2000)  =	10:18:25.45 = 154.60606
  DEC(J2000) = -14:55:55.7  = -14.93215
```
with a 90%-confidence error radius of about 1.10 arc sec. This position is 2.0 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.65. No correction has been made for the expected extinction corresponding to E(B-V) of 0.101.
This source lies within the current (Sector 35) field-of-view of TESS camera 1.
We note that this source is 32 arcseconds from the known ROSAT All-Sky X-ray Survey source 1RXS J101827.6-145604. This is outside of the nominal joint error radius and so we believe that the ROSAT source is a coincidental alignment unrelated to the new GRB and its optical counterpart.
GCN Circular #29546
Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado M.D. Caballero-Garcia, M. A. Castro Tirado (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco, A. Reina (Univ. de Malaga) and F. Rendon (IAA-CSIC and INTA-CEDEA) on behalf of a larger collaboration, report:
Following the Swift trigger of GRB 210222B (Gropp et al. GCNC 29545), the 0.3m BOOTES-1B robotic telescope in Mazagon (Huelva), southern Spain, automatically responded to this burst. Images were taken starting at 22:40:53 UT (~3.5 min after trigger). In the first 10s image, the afterglow reported by UVOT (Gropp et al. GCNC 29545) is detected with magnitude of 15.6 +/- 0.15 (clear filter). Further observations are ongoing.
We thank the staff at INTA-CEDEA for their excellent support.
GCN Circular #29547
R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration:
We observed Swift GRB 210222B (Gropp et al., GCN 29545) with the LCO 1-m Sinistro instrument at the Sutherland, South Africa site, on February 22, from 22:53 to 23:06 UT (corresponding to 0.27 to 0.43 hours from the GRB trigger time) with the Bessel R and I filters.
We performed a series of 3x120s exposures in R and I. We clearly detect an optical source in R and I band in stacked images at a location consistent with the initial UVOT detection (Gropp at al., GCN 29444); this source is not present in either USNO or 2MASS catalogs. Using the USNO-B.1 catalog as reference, we calculate the following magnitudes:
R = 16.95 +/- 0.01
I = 16.32 +/- 0.01
These magnitudes are not corrected for galactic extinction.
R.S. is funded by NSF AST grant #1831682
GCN Circular #29548
Y-L Mong (1); K. Wiersema (2); K. Tse (1); K. Ackley (1); D. K. Galloway (1); M. Dyer (3); J. Lyman (2); K. Ulaczyk (2); D. Steeghs (2); V. Dhillon (3); P. O'Brien (4); G. Ramsay (5); S. Poshyachinda (6); R. Kotak (7); L. Nuttall (8); D. Pollacco (2); R. Breton (9)
((1) Monash University, (2) Warwick University, (3) University of Sheffield, (4) University of Leicester, (5) Armagh Observatory & Planetarium, (6) National Astronomical Research Institute of Thailand, (7) University of Turku, (8) University of Portsmouth, (9) University of Manchester) report on behalf of the GOTO collaboration:
We carried out observations with the Gravitational-wave Optical Transient Observer (GOTO) on La Palma in response to GRB 210222B (Gropp et al; GCN 29545).
We made a series of 4x90 s exposures using our wide L-band filter (400-700 nm) covering the Swift XRT error box, beginning around 54 s after the trigger, with midtime of the first observation 22:42:05.21 UT on 22 February 2021.
We detect an uncatalogued source located at (J2000):
RA 10:18:25.42
Dec +53:24:55.89
confirming the OT reported by MASTER (Lupinov et al.; GCN 29544), BOOTES-1 (Malesani et al.; GCN 29546) and LCO (Strausbaugh et al.; GCN 29547). We find an equivalent magnitude of g = (16.58 +/- 0.03) mag based on calibration against PanSTARRS DR1 photometry in ATLAS_REFCAT2 (Tonry et al. 2018).
Observations are continuing.
GOTO is operated at the La Palma observing facilities of the University of Warwick on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), Turku University, Portsmouth University, Manchester University and the Instituto de Astrofisica de Canarias (IAC) (https://goto-observatory.org)
GCN Circular #29549
D. A. Perley (LJMU) reports:
A short ugriz imaging sequence of the optical afterglow of GRB 210222A (Gropp et al. 29545) was obtained using IO:O on the robotic Liverpool Telescope between 23:39 and 23:50 UT on 2021-02-22. Photometry relative to PS1 standards in the field gives the following magnitudes:
```
t-t0 (d)      magnitude
0.04333 :  g = 18.67 +/- 0.04
0.04440 :  r = 18.21 +/- 0.03
0.04544 :  i = 18.01 +/- 0.03
0.04971 :  z = 17.83 +/- 0.06
```
The g-band photometry lies below an extrapolation of the other bands and the source is not detected in u-band, which may suggest a moderately high redshift.
GCN Circular #29550 (Correction)
Y-L Mong (1); K. Wiersema (2); K. Tse (1); K. Ackley (1); D. K. Galloway (1); M. Dyer (3); J. Lyman (2); K. Ulaczyk (2); D. Steeghs (2); V. Dhillon (3); P. O'Brien (4); G. Ramsay (5); S. Poshyachinda (6); R. Kotak (7); L. Nuttall (8); D. Pollacco (2); R. Breton (9)
((1) Monash University, (2) Warwick University, (3) University of Sheffield, (4) University of Leicester, (5) Armagh Observatory & Planetarium, (6) National Astronomical Research Institute of Thailand, (7) University of Turku, (8) University of Portsmouth, (9) University of Manchester) report on behalf of the GOTO collaboration:
The declination (Dec) of the afterglow candidate reported in GCN29548 is incorrect. The correct position of the detection is
```
RA 10:18:25.42
Dec -14:55:54:63
```
We apologize for any confusion.
GOTO is operated at the La Palma observing facilities of the University of Warwick on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), Turku University, Portsmouth University, Manchester University and the Instituto de Astrofisica de Canarias (IAC) ( https://goto-observatory.org)
GCN Circular #29551
Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 210222B (Gropp et al., GCN 29545) using the NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. Observations automatically started at 22:39:01 UT on 2021-02-22, i.e., 95 s after the BAT trigger. We obtained a series of 40 s and 60 s frames during the local morning twilight in the Sloan r-filter.
The previously reported optical afterglow (Gropp et al., GCN 29545; Hu et al., GCN 29546; Strausbaugh et al., GCN 29547; Mong et al., GCN 29548, 29550; Perley et al., GCN 29549) is detected in the stacked images of the first three exposures, with r = 14.5 +/- 0.3 mag, calibrated with nearby PS1 stars.
GCN Circular #29552
J. F. Agui Fernandez (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), L. Izzo (DARK/NBI), D. Xu (NAOC), D.A. Kann (HETH/IAA-CSIC), D.B. Malesani (DTU Space), J.P.U. Fynbo (DAWN/NBI), K. Wiersema (Warwick U.) report:
We observed the afterglow of GRB 210222B (Gropp et al. GCN 29545; Hu et al. GCN 29546; Strausbaugh et al. GCN 29547; Mong et al. GCN 29548 and GCN 29550; Perley GCN 29549; Zhu et al. GCN 29551) with FORS2, mounted at the Unit Telescope 1 of the Very Large Telescope, at Paranal Observatory, Chile. The observation started at 3:00 UT (4.376 hr after the burst) and consisted of 2x700 s exposures using grism 300V and 2x700 s exposures using grism 300I, which together cover the full range between 3300 and 10100 AA.
In the acquisition image, the afterglow is well detected at V = 19.6 +/- 0.1 mag (Vega).
The spectrum shows continuum over the full range with strong absorption features that we identify as due to Lyman alpha, SII, SiII, SiII*, OI, CII, SiIV, CIV, FeII, AlII and MgII at a common redshift of 2.198, which we identify as the redshift of the GRB. This is consistent with the moderately high redshift already reported by Perley (GCN 29549) based on the photometric decline in the u-band.
We acknowledge excellent support from the ESO staff, in particular Jose Velasquez, Chiara Mazzucchelli, and Jonathan Smoker.
GCN Circular #29554
V. Lipunov, V.Kornilov, E.Gorbovskoy,N.Tiurina,P.Balanutsa,F.Balakin, V.Vladimirov, A.Kuznetsov,K.Zhirkov,D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, A.Chasovnikov,A.Pozdnyakov,V.Topolev, D.Cheryasov(Lomonosov Moscow State University, SAI, Physics Department), D. Buckley (South African Astronomical Observatory), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico FelixAguilar OAFA), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), O.A. Gres, N.M. Budnev (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
MASTER Global robotic net (MASTER-Net:http://observ.pereplet.ru Lipunov et al.,2010,Advances in Astronomy,2010,30L) automatically started (Lipunov et al. GCN 29544) Swift GRB 200222B (J.Gropp et al. GCN 29545,Ttrigger=22:37:26 UT) optical observations at MASTER-Kislovodsk at 2021-02-22 22:38:07UT (41s after trigger time in clouds), at MASTER-SAAO at 2021-02-22 22:42:03UT (GCN 29544).
MASTER auto-detection system found MASTER OT J101825.41-145554.9, also detected by Swift (GCN 29545), and observed by BOOTES-1 (GCN 29546), LCO (29547), GOTO(29548), Liverpool Telescope (GCN 29549), NEXT (29551),VLT (GCN 29551) This OT was also observed by MASTER-IAC.
The reduction of MASTER wide field and very wide field cameras images will be continued. This message may be cited.
GCN Circular #29557
Martin Jelinek and Jan Strobl (ASU CAS Ondrejov, CZ), Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek, Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza (Institute of Physics, Prague, CZ)
report:
The 25cm robotic telescope FRAM-ORM at La Palma (Spain) reacted robotically to the alert of GRB210222B (Gropp et al. GCNC 29545, Marrocchesi et al. GCNC 29553), obtaining a series of 20 s unfiltered images starting at 22:38:21.1 UT, i.e. 55.1s post trigger.
We clearly detect the source reported by other telescopes (Hu et al. GCNC 29546, Strausbaugh et al. GCNC 29547, Mong et al. GCNC 29548, Perley GCNC 29549, Agui Fernandez et al. GCNC 29552, and Lipunov et al. GCNC 29554). As seen by FRAM, the brightness of the object reached a maximum of about R(Vega) ~ 15.5, similarly to the value of BOOTES, and then slowly changed to a decay with an index alpha = ~1.1.
Would the decay stay at this rate, the afterglow may have a brightness of R~22.0 24h post trigger.
GCN Circular #29558
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 210222B (Gropp et al., GCN 29545) starting at ~0.44 days after the burst. A total of 30x60s images were obtained in the clear (roughly R) filters. We do not detect the optical afterglow (Gropp et al., GCN 29545; Hu et al., GCNC 29546; Strausbaugh et al., GCNC 29547; Mong et al., GCNC 29548; Perley, GCNC 29549; Agui Fernandez et al., GCNC 29552; Lipunov et al., GCNC 29554; Jelinek et al., GCN 29557) in the co-add images, down to a limiting magnitude of ~20.0 mag calibrated to the USNOB1.0 catalog.
GCN Circular #29559
M. H. Siegel (PSU) and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210222B 101 s after the BAT trigger (Gropp et al., GCN Circ. 29545). A source consistent with the XRT position (Gropp et al. GCN Circ. 29545) is detected in the initial UVOT exposures. This source is also consistent with previously reported optical detections (Hu et al., GCN Circ. 29546; Strausbaugh, GCN Circ. 29547; Mong et al., GCN Circ. 29548; Parley, GCN Circ. 29549; Zhu et al., GCN Circ. 29551, Lipunov et al., GCN Circ. 29554). We note that the lack of detection in the NUV passbands would be consistent with the redshift of 2.198 reported by Agui Fernandez et al. (GCN Circ. 29552).
The preliminary UVOT position is:
```
   RA  (J2000) =  10:18:25.43 = 154.60595 (deg.)
   Dec (J2000) = -14:55:55.1  = -14.93198 (deg.)
```
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              101          250          147         16.89 +/- 0.03
v                  588          608           19         16.80 +/- 0.17
b                  515          534           20         17.24 +/- 0.12
u                  259          508          246         16.82 +/- 0.04
w1                 639         1793          124        >18.8
m2                 614         1606           78        >20.1
w2                 564         1732          136        >19.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.102 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #29560
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), P.A. Evans (U. Leicester) and J.D. Gropp report on behalf of the Swift-XRT team:
We have analysed 6.2 ks of XRT data for the Swift-BAT-detected burst GRB 210222B (Gropp et al. GCN Circ. 29545), from 111 s to 63.2 ks after the Swift-BAT trigger. The data are entirely in Photon Counting (PC) mode. Using 2754 s of PC mode data and 4 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 154.60574, -14.93170 which is equivalent to:
```
RA (J2000): 10h 18m 25.38s
Dec(J2000): -14d 55' 54.1"
```
with an uncertainty of 1.4 arcsec (radius, 90% confidence). This position is 2.2 arcmin from the Swift-BAT position.
The light curve can be modelled with an initial power-law decay with an index of alpha=0.19 (+/-0.16), followed by a break at T+827 s to an alpha of 1.30 (+0.12, -0.08).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.98 (+0.15, -0.14). The best-fitting absorption column is 1.4 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 8.9 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.4 (+0.5, -0.4) x 10^21 cm^-2
Galactic foreground: 8.9 x 10^20 cm^-2
Excess significance: 1.9 sigma
Photon index:	     1.98 (+0.15, -0.14)
```
If the light curve continues to decay with a power-law decay index of 1.30, the count rate at T+24 hours will be 3.1 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x 10^-13 (1.4 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01034325.
This circular is an official product of the Swift-XRT team.
GCN Circular #29561
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (PSU) M. Stamatikos (OSU), (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210222B (trigger #1034325) (Gropp et al., GCN Circ. 29545). The BAT ground-calculated position is RA, Dec = 154.631, -14.946 deg which is
```
   RA(J2000)  =  10h 18m 31.4s
   Dec(J2000) = -14d 56' 45.7"
```
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 38%.
The BAT light curve showed a two peaked structure with a duration of about ~20 sec. T90 (15-350 keV) is 12.82 +- 1.28 sec (estimated error including systematics).
The time-averaged spectrum from T-11.37 to T+2.72 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.37 +- 0.33. The fluence in the 15-150 keV band is 3.4 +- 0.7 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+0.87 sec in the 15-150 keV band is 1.4 +- 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/1034325/BA/
GCN Circular #29562
P. Gokuldass (UVI), N. Orange (OrangeWave Innovative Science, LLC), R. Strausbaugh (UVI), A. Cucchiara (UVI/College of Marin), D. Morris (UVI) report:
We observed the field of GRB210222B (Gropp et al, GCN 29545) with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 02-23-2021 starting at 02:14:31 UT (T+3.6hrs). We performed a series of exposures in R filter with a total exposure of 4600 s. The weather conditions were clear during the hours of observation with an average air masses as shown in the table below.
We detect the optical transient reported by others (Gropp et al., GCN 29545, Hu et al., GCN 29546,Strausbaugh et al., GCN 29547, Mong et al., GCN 29548, Perley, GCN 29549, Aqui Fernandez et al., GCN 29552, Lipunov et al., GCN 29554, Jelinik et al., GCN 29557) at > 3-sigma confidence with magnitudes as reported below:
```
T_mid       ||Exposure     ||Filter      ||Limit         ||Airmass
T+4.5 hrs   ||2000s        ||R           ||18.5 +/- 0.1  ||1.7
T+8.5 hrs   ||2600s	   ||R           ||20.0 +/- 0.2  ||1.5
```
The magnitude is estimated from comparison to nearby USNO B1 stars and is not corrected for Galactic extinction. Further analysis is in progress. The VIRT is still in the commissioning phase.
This work is supported by NASA-MUREP-MIRO grant NNX15AP95A, NSF EiR AST Award 1901296, and NSF HBCU-UP AST Award 1831682. This message can be cited.
GCN Circular #29563
S. Belkin (IKI), A. Pozanenko (IKI), A. Novichonok (Petrozavodsk State University, KIAM), A. Zhornichenko (KIAM), N. Pankov (HSE) report on behalf of IKI GRB FuN:
We observed the field of GRB 210222B (Gropp et al., GCN 29545) with Zeiss-1000 telescope of Koshka observatory starting on Feb. 22 (UT) 22:46:13, i.e. about 12.8 minutes after GRB trigger. We clearly detect optical afterglow (Gropp et al., GCN 29545; Hu et al., GCN 29546; Strausbaugh et al., GCN 29547; Mong et al., GCNs 29548, 29550; Perley et al., GCN 29549; Zhu et al., GCN 29551; Lipunov et al., GCN 29554; Jelinek et al., GCN 29557; Zheng et al., GCN 29558; Siegel et al., GCN 29559; Gokuldass et al., GCN 29562). Observations were performed under non-optimal weather conditions.
Preliminary photometry of the afterglow is following
```
Date       UT start   t-T0       Filter Exp.    OT    Err.  UL(3sigma)
                       (mid, days)        (s)

2020-12-03 20:50:46   0.58216    R      120*25   n/d  n/d   20.5

Date,       UT start  Exptime,s t-T0,d   Filter OT    Err  UL(3sigma)
2021-02-22 22:46:13     240   0,00748842 R      16.27 0.09 18.3
2021-02-22 22:50:18     240   0,01032407 R      16.49 0.11 18.2
2021-02-22 22:55:50     240   0,01416666 R      16.71 0.11 18.2
2021-02-22 22:59:54    5*240  0,02254629 R      17.18 0.18 18.7
2021-02-22 23:20:18    7*240  0,03949074 R      17.60 0.15 18.9
```
The photometry is based on the nearby USNO-B1.0 stars
```
USNO-B1.0_id R2
0750-0233028 14.52
0750-0233056 15.22
0750-0233031 15.24
```
The light curve can be found in http://grb.rssi.ru/GRB210222B/GRB210222B_LC.png Based only on our photometry we estimated power law index of the afterglow light curve of -0.74.
We are grateful to the “Terskol Observatory” Center of the Institute of Astronomy of the Russian Academy of Sciences (INASAN) for the observations with the Zeiss-1000 telescope on Mount Koshka at the Simeiz Observatory.
GCN Circular #29565
R. Hosokawa, K. L. Murata, R. Adachi, M. Niwano, F. Ogawa, N. Nakamura, N. Ito, S. Ogata, H. Takamatsu, H. Hara, Y. Yatsu, and N. Kawai (TokyoTech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 210222B (Lipunov et al. GCN #29544, Gropp et al. GCN #29545, Hu et al. GCN #29546, Strausbaugh et al. GCN #29547, Mong et al. GCN #29548, Perley et al. GCN #29549, Mong et al. GCN #29550, Zhu et al. GCN #29551, Fernandez et al. GCN #29552, Lipunov et al. GCN #29554, Jelinek et al. GCN #29557, Zheng et al. GCN #29558, Siegel et al. GCN #29559, Page et al. GCN #29560, Ukwatta et al. GCN #29561, Gokuldass et al. GCN #29562, Belkin et al. GCN #29563) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation with a series of 60 sec exposures started at 2021-02-23 11:00:13 UT(12.4hours after the Swift BAT trigger). We stacked the images with good conditions. We did not detect the optical afterglow reported previously (Gropp et al. GCN #29545, Hu et al. GCN #29546, Strausbaugh et al. GCN #29547, Mong et al. GCN #29548, Perley et al. GCN #29549, Mong et al. GCN #29550, Zhu et al. GCN #29551, Fernandez et al. GCN #29552, Lipunov et al. GCN #29554, Jelinek et al. GCN #29557, Siegel et al. GCN #29559, Gokuldass et al. GCN #29562, Belkin et al. GCN #29563) in all three bands. We obtained the 5-sigma limits of the stacked images as follows.
```
T0+[hour] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
12.4 15:18:25 14100 g'>19.6, Rc>19.9, Ic>19.2
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used the PS1 catalog for flux calibration. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).
GCN Circular #29567
P. D'Avanzo, S. Covino, D. Fugazza, A. Melandri (INAF-OAB) on behalf of the REM team, report:
We observed the field of GRB 210222B (Gropp et al., GCN Circ. 29545) with the REM 60cm robotic telescope located at the ESO premise of La Silla (Chile). The observations were performed starting on 2021 February 23 at 00:18:20 UT (i.e. 1.68 hours after the burst) and were carried in the g, r, i, z, J and H bands.
The optical afterglow (Gropp et al., GCN Circ. 29545) is detected in all bands.
From preliminary photometry we obtain for the optical/NIR afterglow the following magnitudes:
```
r = 18.85 +/- 0.13 (AB; calibrated against the Pan-STARRS catalogue)
H = 16.39 +/- 0.20 (Vega; calibrated against the 2MASS catalogue)
```
at a mid time of t-t0 = 1.93 hours.
GCN Circular #29569
Rahul Gupta, A. Kumar, Dimple, A. Ghosh, A. Aryan, V. Negi, B. Kumar, S. B. Pandey, and K. Misra (ARIES) report:
We observed the field of Swift detected GRB 210222B (Gropp et al., GCN 29545) with 1.3m Devasthal Fast Optical Telescope (DFOT) located at Devasthal observatory of Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2021-02-23 at ~ 19:15 UT, i.e., ~ 20.6 hours after the BAT trigger. We have taken multiple frames having an exposure time of 120 s in the R and I filters. We stacked the images after the alignment. We did not detect the optical afterglow reported previously (Gropp et al. GCN 29545; Hu et al. GCN 29546; Strausbaugh et al. GCN 29547; Mong et al. GCN 29548, 29550; Perley et al. GCN 29549; Zhu et al. GCN 29551, Fernandez et al. GCN 29552; Lipunov et al. GCN 29554; Jelinek et al. GCN 29557; Siegel et al. GCN 29559; Gokuldass et al. GCN 29562; Belkin et al. GCN 29563; and D'Avanzo et al. GCN 29567) in our stacked image.
We obtain the following 3-sigma upper limit in the stacked image.
Date Start_UT T_start-T0 (hour) Filter Exp time (s) Limiting magnitude ==================================================== 2021-02-23 19:15 ~20.6 R 120*30 > 21.1 The magnitude is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalog. This circular may be cited.
GCN Circular #31753
A. Klotz (CNRS-OMP-IRAP), M. Fortune, R. Augerai (Universite de la Renuion), P. Thierry� (AGORA), L. Eymar, S. Antier, M. Boer, A. de Ugarte Postigo (CNRS-OCA-ARTEMIS),
We analyzed archive images of the SWIFT trigger 1034325 (GRB 210222B, BAT detection by Gropp et al. GCN Circ. 29545, early optical ground observations by Fernandez-Garcia et al. GCN Circ. 29546, redshift by Agui Fernandez et al. GCN Circ. 29552) with the TAROT robotic telescope (D=18cm) located at Les Makes Observatory, Reunion Island, France.
Images were acquired without any filter, camera FLI PL16803 and Takahashi Epsilon 180ED.
According the reference star NOMAD-1 0750-0237314 R=15.43 we give the photometry of the GRB optical transient:
```
t1(s) t2(s)���� R� dmag
 � 342�� 433 15.76� 0.06
 � 439�� 529 16.08� 0.07
 � 536�� 626 16.14� 0.08
 � 658�� 748 16.28� 0.09
 � 755�� 845 16.38� 0.09
 � 853�� 942 16.38� 0.09
 �1526� 1706 16.98� 0.12
 �1714� 1894 17.28� 0.15
 �1902� 2543 17.32� 0.13
 �2550� 3317 17.74� 0.21
 �3347� 4843 17.92� 0.25
 �4852� 6755 18.52� 0.47
```
t1 and t2 are start and stop acquisition since the trigger.
Magnitudes are not corrected for Galactic dust extinction.

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Jochen Greiner, last update: 13-Mar-2022 [Disclaimer]