Gamma-ray Burst 230123A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Jan 23 10:20:04 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1150429,   Seg_Num: 0
GRB_RA:           40.937d {+02h 43m 45s} (J2000),
                  41.046d {+02h 44m 11s} (current),
                  40.701d {+02h 42m 48s} (1950)
GRB_DEC:         -65.676d {-65d 40' 33"} (J2000),
                 -65.579d {-65d 34' 44"} (current),
                 -65.887d {-65d 53' 11"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       1797 [cnts]    Image_Peak=124 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   137     E_range: 15-50 keV
BKG_INTEN:       10227 [cnts]
BKG_TIME:        37169.37 SOD {10:19:29.37} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19967 TJD;    23 DOY;   23/01/23
GRB_TIME:        37184.92 SOD {10:19:44.92} UT
GRB_PHI:         135.88 [deg]
GRB_THETA:        17.29 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.60 [sigma]
IMAGE_SIGNIF:    7.59 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +1  -2  +0  +0 -26  +0 
SUN_POSTN:       305.44d {+20h 21m 45s}  -19.45d {-19d 27' 07"}
SUN_DIST:         74.63 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.30d {+21h 57m 13s}  -17.59d {-17d 35' 11"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.21,-47.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      339.74,-70.63 [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 = 116.97,-3.94 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Jan 23 10:21:29 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.947d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 21"} (J2000)
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37273.69 SOD {10:21:13.69} UT,   88.8 [sec] since BAT Trigger Time
COUNTS:          10    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 23 Jan 23 10:23:24 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1150429,   Seg_Num: 0
GRB_RA:           40.937d {+02h 43m 45s} (J2000),
                  41.046d {+02h 44m 11s} (current),
                  40.701d {+02h 42m 48s} (1950)
GRB_DEC:         -65.676d {-65d 40' 33"} (J2000),
                 -65.579d {-65d 34' 44"} (current),
                 -65.887d {-65d 53' 11"} (1950)
GRB_DATE:        19967 TJD;    23 DOY;   23/01/23
GRB_TIME:        37184.92 SOD {10:19:44.92} UT
TRIGGER_INDEX:   137
GRB_PHI:         135.88 [deg]
GRB_THETA:        17.29 [deg]
DELTA_TIME:      45.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.60 [sigma]
IMAGE_SIGNIF:    7.59 [sigma]
LC_URL:          sw01150429000msb.lc
SUN_POSTN:       305.44d {+20h 21m 45s}  -19.45d {-19d 27' 05"}
SUN_DIST:         74.63 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.34d {+21h 57m 21s}  -17.57d {-17d 34' 25"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.21,-47.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      339.74,-70.63 [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 = 116.97,-3.94 [deg].  
COMMENTS:        The 2nd packet (of 3) was missing in the lightcurve data stream.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Jan 23 10:24:19 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.947d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 21"} (J2000)
POINT_ROLL:      256.845d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37277.04 SOD {10:21:17.04} UT,   92.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.588
N_STARS:         38
X_OFFSET:        524 [pixels]
Y_OFFSET:        640 [pixels]
X_MAX:           1483 [pixels]
Y_MAX:           1599 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01150429000msufc0092.fits
SUN_POSTN:       305.44d {+20h 21m 46s}  -19.45d {-19d 27' 04"}
SUN_DIST:         74.63 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.35d {+21h 57m 23s}  -17.57d {-17d 34' 13"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Jan 23 10:24:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.947d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 21"} (J2000)
POINT_ROLL:      256.845d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37277.04 SOD {10:21:17.04} UT,   92.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.588
N_STARS:         38
X_OFFSET:        524 [pixels]
Y_OFFSET:        640 [pixels]
X_MAX:           1483 [pixels]
Y_MAX:           1599 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01150429000msufc0092.fits
SUN_POSTN:       305.44d {+20h 21m 46s}  -19.45d {-19d 27' 04"}
SUN_DIST:         74.63 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.35d {+21h 57m 24s}  -17.57d {-17d 34' 11"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [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 23 Jan 23 10:25:50 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.947d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 21"} (J2000)
ROLL:            256.845d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37277.04 SOD {10:21:17.04} UT,   92.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     696162107
X_OFFSET:        843 [pixels]
Y_OFFSET:        959 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1003
Y_GRB_POS:       1119
BINNING_INDEX:   1
IM_URL:          sw01150429000msuni0123.fits
SUN_POSTN:       305.44d {+20h 21m 46s}  -19.45d {-19d 27' 03"}
SUN_DIST:         74.63 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.36d {+21h 57m 27s}  -17.56d {-17d 33' 52"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [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 23 Jan 23 10:25:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.947d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 21"} (J2000)
ROLL:            256.845d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37277.04 SOD {10:21:17.04} UT,   92.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     696162107
X_OFFSET:        843 [pixels]
Y_OFFSET:        959 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1003
Y_GRB_POS:       1119
BINNING_INDEX:   1
IM_URL:          sw01150429000msuni0123.fits
SUN_POSTN:       305.44d {+20h 21m 46s}  -19.45d {-19d 27' 03"}
SUN_DIST:         74.63 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.36d {+21h 57m 27s}  -17.56d {-17d 33' 51"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [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 23 Jan 23 10:28:31 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1150429,   Seg_Num: 0
GRB_RA:           40.8615d {+02h 43m 26.75s} (J2000),
                  40.9713d {+02h 43m 53.11s} (current),
                  40.6251d {+02h 42m 30.03s} (1950)
GRB_DEC:         -65.6858d {-65d 41' 08.8"} (J2000),
                 -65.5888d {-65d 35' 19.6"} (current),
                 -65.8967d {-65d 53' 48.2"} (1950)
GRB_ERROR:       4.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37353.00 SOD {10:22:33.00} UT,   168.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       305.44d {+20h 21m 46s}  -19.45d {-19d 27' 02"}
SUN_DIST:         74.59 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.39d {+21h 57m 33s}  -17.55d {-17d 33' 15"}
MOON_DIST:        66.48 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.25,-47.65 [deg] galactic lon,lat of the burst
ECL_COORDS:      339.67,-70.61 [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 1.1% < P(seren) < 2.8%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Jan 23 10:32:52 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.944d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 19"} (J2000)
POINT_ROLL:      256.847d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37489.28 SOD {10:24:49.28} UT,   304.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.364
N_STARS:         72
X_OFFSET:        284 [pixels]
Y_OFFSET:        400 [pixels]
X_MAX:           1723 [pixels]
Y_MAX:           1839 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw01150429000msufc0304.fits
SUN_POSTN:       305.45d {+20h 21m 47s}  -19.45d {-19d 27' 00"}
SUN_DIST:         74.62 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.43d {+21h 57m 44s}  -17.54d {-17d 32' 16"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Jan 23 10:33:07 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.944d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 19"} (J2000)
POINT_ROLL:      256.847d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37489.28 SOD {10:24:49.28} UT,   304.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.364
N_STARS:         72
X_OFFSET:        284 [pixels]
Y_OFFSET:        400 [pixels]
X_MAX:           1723 [pixels]
Y_MAX:           1839 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw01150429000msufc0304.fits
SUN_POSTN:       305.45d {+20h 21m 47s}  -19.45d {-19d 27' 00"}
SUN_DIST:         74.62 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.44d {+21h 57m 45s}  -17.54d {-17d 32' 12"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [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 23 Jan 23 10:34:02 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.944d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 19"} (J2000)
ROLL:            256.847d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37489.28 SOD {10:24:49.28} UT,   304.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     696162319
X_OFFSET:        843 [pixels]
Y_OFFSET:        959 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1003
Y_GRB_POS:       1119
BINNING_INDEX:   1
IM_URL:          sw01150429000msuni0335.fits
SUN_POSTN:       305.45d {+20h 21m 47s}  -19.45d {-19d 26' 59"}
SUN_DIST:         74.62 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.45d {+21h 57m 47s}  -17.53d {-17d 32' 00"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [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 23 Jan 23 10:34:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.944d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 19"} (J2000)
ROLL:            256.847d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37489.28 SOD {10:24:49.28} UT,   304.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     696162319
X_OFFSET:        843 [pixels]
Y_OFFSET:        959 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1003
Y_GRB_POS:       1119
BINNING_INDEX:   1
IM_URL:          sw01150429000msuni0335.fits
SUN_POSTN:       305.45d {+20h 21m 47s}  -19.45d {-19d 26' 59"}
SUN_DIST:         74.62 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.45d {+21h 57m 47s}  -17.53d {-17d 31' 57"}
MOON_DIST:        66.51 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [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 23 Jan 23 10:33:50 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1150429,   Seg_Num: 0
GRB_RA:           40.8597d {+02h 43m 26.32s} (J2000),
                  40.9695d {+02h 43m 52.67s} (current),
                  40.6233d {+02h 42m 29.59s} (1950)
GRB_DEC:         -65.6867d {-65d 41' 12.1"} (J2000),
                 -65.5897d {-65d 35' 22.8"} (current),
                 -65.8976d {-65d 53' 51.4"} (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:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  37353.00 SOD {10:22:33.00} UT,   168.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       305.45d {+20h 21m 47s}  -19.45d {-19d 26' 59"}
SUN_DIST:         74.59 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.44d {+21h 57m 46s}  -17.53d {-17d 32' 03"}
MOON_DIST:        66.47 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.26,-47.65 [deg] galactic lon,lat of the burst
ECL_COORDS:      339.67,-70.61 [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 1.1% < P(seren) < 2.8%.

GCN Circular #33206
M. A. Williams (PSU), R. A. J. Eyles-Ferris (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (U Tampa) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team:
At 10:19:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 230123A (trigger=1150429). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 40.937, -65.676 which is
```
   RA(J2000) = 02h 43m 45s
   Dec(J2000) = -65d 40' 33"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 10 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~1 sec after the trigger. The immediately available BAT light curve does not include data from ~T+8 s to ~T+100 s. There might be additional burst emission in that time interval.
The XRT began observing the field at 10:21:13.6 UT, 88.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 40.85977, -65.68672 which is equivalent to:
```
   RA(J2000)  = 02h 43m 26.34s
   Dec(J2000) = -65d 41' 12.2"
```
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 120 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 (2.95 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 1.3 (+1.44/-1.26) x 10^22 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 92 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 12% of the XRT 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 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 0.022.
Burst Advocate for this burst is M. A. Williams (mjw6837 AT psu.edu). 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 23 Jan 23 10:39:59 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.944d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 20"} (J2000)
POINT_ROLL:      256.846d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  38044.80 SOD {10:34:04.80} UT,   859.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.469
N_STARS:         161
X_OFFSET:        284 [pixels]
Y_OFFSET:        400 [pixels]
X_MAX:           1723 [pixels]
Y_MAX:           1839 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw01150429000msufc0859.fits
SUN_POSTN:       305.45d {+20h 21m 48s}  -19.45d {-19d 26' 55"}
SUN_DIST:         74.62 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.51d {+21h 58m 01s}  -17.51d {-17d 30' 38"}
MOON_DIST:        66.50 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 23 Jan 23 10:40:18 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.944d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 20"} (J2000)
POINT_ROLL:      256.846d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  38044.80 SOD {10:34:04.80} UT,   859.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.469
N_STARS:         161
X_OFFSET:        284 [pixels]
Y_OFFSET:        400 [pixels]
X_MAX:           1723 [pixels]
Y_MAX:           1839 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw01150429000msufc0859.fits
SUN_POSTN:       305.45d {+20h 21m 48s}  -19.45d {-19d 26' 55"}
SUN_DIST:         74.62 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.51d {+21h 58m 02s}  -17.51d {-17d 30' 34"}
MOON_DIST:        66.50 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [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 23 Jan 23 10:41:56 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.944d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 20"} (J2000)
ROLL:            256.846d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  38044.80 SOD {10:34:04.80} UT,   859.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     696162875
X_OFFSET:        843 [pixels]
Y_OFFSET:        959 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1003
Y_GRB_POS:       1119
BINNING_INDEX:   1
IM_URL:          sw01150429000msuni0890.fits
SUN_POSTN:       305.45d {+20h 21m 49s}  -19.45d {-19d 26' 54"}
SUN_DIST:         74.62 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.53d {+21h 58m 06s}  -17.50d {-17d 30' 12"}
MOON_DIST:        66.50 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [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 23 Jan 23 10:42:09 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1150429,   Seg_Num: 0
POINT_RA:         40.944d {+02h 43m 47s} (J2000)
POINT_DEC:       -65.689d {-65d 41' 20"} (J2000)
ROLL:            256.846d
IMG_START_DATE:  19967 TJD;    23 DOY;   23/01/23
IMG_START_TIME:  38044.80 SOD {10:34:04.80} UT,   859.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     696162875
X_OFFSET:        843 [pixels]
Y_OFFSET:        959 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1003
Y_GRB_POS:       1119
BINNING_INDEX:   1
IM_URL:          sw01150429000msuni0890.fits
SUN_POSTN:       305.45d {+20h 21m 49s}  -19.45d {-19d 26' 54"}
SUN_DIST:         74.62 [deg]   Sun_angle= -6.4 [hr] (East of Sun)
MOON_POSTN:      329.53d {+21h 58m 07s}  -17.50d {-17d 30' 09"}
MOON_DIST:        66.50 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:      286.22,-47.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      339.71,-70.64 [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 #33208
B. Gendre (UWA/OzGrav), G. Stratta (INAF/Goethe University Frankfurt), E. Moore (UWA/OzGrav), F. Panther (UWA/OzGrav), D. Coward (UWA/OzGrav), J. A. Moore (OzGrav-UWA), A. Klotz (IRAP-CNRS-OMP), and P. Thierry (AGORA) report:
We imaged the field of GRB 230123A detected by SWIFT (trigger 1150429, GCN 33206, Williams et al. 2023) with the Zadko robotic telescope (D=100cm) located at the Zadko observatory - Gingin, Australia.
The observations started 2.56h after the GRB trigger (t0+9213.4s). The elevation of the field decreased from 51 degrees above horizon and weather conditions were good.
We observed the field for one hour, and have not detected any afterglow down to magnitude 18.7 in individual images. On a stack of 6 images, we reached an upper limit of R = 19.0 with no detection of the afterglow. Further observations are planned.
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
N.B. Galactic coordinates are lon=286.2098 lat=-47.6419 and the galactic extinction in R band is 0.0 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S.
This message may be cited. ======================================================================
GCN Circular #33209
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1184 s of XRT Photon Counting mode data and 2 UVOT images for GRB 230123A, 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 = 40.85842, -65.68648 which is equivalent to:
```
RA (J2000): 02h 43m 26.02s
Dec (J2000): -65d 41' 11.3"
```
with an uncertainty of 4.1 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 #33210
S. Dichiara (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto) and M.A. Williams report on behalf of the Swift-XRT team:
We have analysed 6.4 ks of XRT data for GRB 230123A (Williams et al. GCN Circ. 33206), from 73 s to 18.4 ks after the BAT trigger. The data comprise 8 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 33209).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.68 (+0.08, -0.07).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.1 (+0.4, -0.3). The best-fitting absorption column is 1.4 (+1.0, -0.8) x 10^21 cm^-2, in excess of the Galactic value of 3.0 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 3.2 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.4 (+1.0, -0.8) x 10^21 cm^-2
Galactic foreground: 3.0 x 10^20 cm^-2
Excess significance: 2.2 sigma
Photon index:	     2.1 (+0.4, -0.3)
```
If the light curve continues to decay with a power-law decay index of 0.68, the count rate at T+24 hours will be 3.4 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/01150429.
This circular is an official product of the Swift-XRT team.
GCN Circular #33211
A. Belles (PSU) and M. Williams (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230123A 93 s after the BAT trigger (Williams et al., GCN Circ. 33206). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 33209) 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            93          243          147         >20.6
u_FC               305          555          246         >20.6
white               93         1704          412         >21.0
v                  637         1754          136         >19.4
b                  562         1679          117         >20.0
u                  305         1825          359         >20.5
w1                 686         1804          117         >20.8
m2                1412         1605           39         >18.7
w2                 612         1209           78         >20.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.022 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #33214
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU), M. A. Williams (PSU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 230123A (trigger #1150429) (Williams et al., GCN Circ. 33206). The BAT ground-calculated position is RA, Dec = 40.905, -65.661 deg which is
```
   RA(J2000)  =  02h 43m 37.3s
   Dec(J2000) = -65d 39' 39.9"
```
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 88%.
The mask-weighted light curve shows a single-peaked structure that starts at ~T-2 s, peaks at ~T+1, and ends at ~T+6 s. T90 (15-350 keV) is 5.37 +- 1.03 sec (estimated error including systematics).
The time-averaged spectrum from T-1.25 to T+4.75 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.06 +- 0.24. The fluence in the 15-150 keV band is 2.7 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.12 sec in the 15-150 keV band is 1.1 +- 0.2 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/1150429/BA/
GCN Circular #33217
R. Strausbaugh (University of Minnesota), A. Cucchiara (NASA) report on behalf of a larger collaboration:
We observed the GRB 230123A (Williams et al., GCN 33206) field with the LCOGT 1-meter Sinistro instrument at the Cerro Tololo Interamerican Observatory, Chile site, on January 24, from 02:06 to 02:38 UT (corresponding to 15.78 to 16.32 hours from the GRB trigger time) with the Bessel R and I filters.
We performed a series of 3x300s exposures in each band. We do not detect a source in either band within the XRT enhanced error region (Beardmore et al., GCN 33209), consistent with other optical upper limits (Gendre et al., GCN 33208; Belles et al., 33211).
The following upper limits are calculated using the USNO-B1.0 catalog as reference:
```
R > 20.8
I > 20.1
```
These magnitudes are not corrected for galactic extinction.

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Jochen Greiner, last update: 24-Jan-2023 [Disclaimer]