Gamma-ray Burst 250114A

(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:     Tue 14 Jan 25 07:33:56 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1281241,   Seg_Num: 0
GRB_RA:          166.590d {+11h 06m 22s} (J2000),
                 166.902d {+11h 07m 37s} (current),
                 165.967d {+11h 03m 52s} (1950)
GRB_DEC:         -15.143d {-15d 08' 34"} (J2000),
                 -15.279d {-15d 16' 43"} (current),
                 -14.873d {-14d 52' 21"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       9127 [cnts]    Image_Peak=185 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   299     E_range: 25-100 keV
BKG_INTEN:       80093 [cnts]
BKG_TIME:        27141.10 SOD {07:32:21.10} UT
BKG_DUR:         40 [sec]
GRB_DATE:        20689 TJD;    14 DOY;   25/01/14
GRB_TIME:        27199.47 SOD {07:33:19.47} UT
GRB_PHI:          39.29 [deg]
GRB_THETA:        41.20 [deg]
SOLN_STATUS:     0x83
RATE_SIGNIF:     9.38 [sigma]
IMAGE_SIGNIF:    6.87 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  -3  +0  +0 +48  +0 
SUN_POSTN:       296.29d {+19h 45m 10s}  -21.24d {-21d 14' 14"}
SUN_DIST:        118.37 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.20d {+08h 08m 49s}  +24.58d {+24d 35' 02"}
MOON_DIST:        59.08 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.67, 40.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      173.83,-19.19 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 295.71,18.87 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:36:08 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     1281241,   Seg_Num: 0
GRB_RA:          166.5767d {+11h 06m 18.4s} (J2000),
                 166.8888d {+11h 07m 33.3s} (current),
                 165.9539d {+11h 03m 48.9s} (1950)
GRB_DEC:         -15.1107d {-15d 06' 38.5"} (J2000),
                 -15.2464d {-15d 14' 46.9"} (current),
                 -14.8403d {-14d 50' 24.9"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       113 [cnts]
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27327.76 SOD {07:35:27.76} UT,   128.3 [sec] since BAT Trigger Time
CENTROID_X:      332.20,  raw= 332  [pixels]
CENTROID_Y:      330.98,  raw= 331  [pixels]
ROLL:            125.18 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   76.09
GRB_POS_XRT_Z:   48.57
IMAGE_URL:       sw01281241000msxps_rw.img
SUN_POSTN:       296.29d {+19h 45m 10s}  -21.24d {-21d 14' 13"}
SUN_DIST:        118.40 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.23d {+08h 08m 54s}  +24.58d {+24d 34' 44"}
MOON_DIST:        59.03 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.63, 40.66 [deg] galactic lon,lat of the burst
ECL_COORDS:      173.81,-19.17 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:36:11 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     1281241,   Seg_Num: 0
GRB_RA:          166.5767d {+11h 06m 18.4s} (J2000),
                 166.8888d {+11h 07m 33.3s} (current),
                 165.9539d {+11h 03m 48.9s} (1950)
GRB_DEC:         -15.1107d {-15d 06' 38.5"} (J2000),
                 -15.2464d {-15d 14' 46.9"} (current),
                 -14.8403d {-14d 50' 24.9"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       113 [cnts]
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27327.76 SOD {07:35:27.76} UT,   128.3 [sec] since BAT Trigger Time
CENTROID_X:      332.20,  raw= 332  [pixels]
CENTROID_Y:      330.98,  raw= 331  [pixels]
ROLL:            125.18 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   76.09
GRB_POS_XRT_Z:   48.57
IMAGE_URL:       sw01281241000msxps_rw.img
SUN_POSTN:       296.29d {+19h 45m 10s}  -21.24d {-21d 14' 13"}
SUN_DIST:        118.40 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.23d {+08h 08m 54s}  +24.58d {+24d 34' 43"}
MOON_DIST:        59.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.63, 40.66 [deg] galactic lon,lat of the burst
ECL_COORDS:      173.81,-19.17 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:35:58 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1281241,   Seg_Num: 0
GRB_RA:          166.5767d {+11h 06m 18.40s} (J2000),
                 166.8888d {+11h 07m 33.31s} (current),
                 165.9539d {+11h 03m 48.92s} (1950)
GRB_DEC:         -15.1107d {-15d 06' 38.5"} (J2000),
                 -15.2464d {-15d 14' 46.9"} (current),
                 -14.8403d {-14d 50' 24.9"} (1950)
GRB_ERROR:       4.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       4.84e-09 [erg/cm2/sec]
GRB_SIGNIF:      10.63 [sigma]
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27327.76 SOD {07:35:27.76} UT,   128.3 [sec] since BAT Trigger Time
TAM[0-3]:        327.62 237.18 261.53 243.80
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       296.29d {+19h 45m 10s}  -21.24d {-21d 14' 13"}
SUN_DIST:        118.40 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.22d {+08h 08m 54s}  +24.58d {+24d 34' 45"}
MOON_DIST:        59.03 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.63, 40.66 [deg] galactic lon,lat of the burst
ECL_COORDS:      173.81,-19.17 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 2.09 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:37:45 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1281241,   Seg_Num: 0
GRB_RA:          166.590d {+11h 06m 22s} (J2000),
                 166.902d {+11h 07m 37s} (current),
                 165.967d {+11h 03m 52s} (1950)
GRB_DEC:         -15.143d {-15d 08' 34"} (J2000),
                 -15.279d {-15d 16' 43"} (current),
                 -14.873d {-14d 52' 21"} (1950)
GRB_DATE:        20689 TJD;    14 DOY;   25/01/14
GRB_TIME:        27199.47 SOD {07:33:19.47} UT
TRIGGER_INDEX:   299
GRB_PHI:          39.29 [deg]
GRB_THETA:        41.20 [deg]
DELTA_TIME:      -76.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x83
RATE_SIGNIF:     9.38 [sigma]
IMAGE_SIGNIF:    6.87 [sigma]
LC_URL:          sw01281241000msb.lc
SUN_POSTN:       296.29d {+19h 45m 11s}  -21.24d {-21d 14' 12"}
SUN_DIST:        118.37 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.24d {+08h 08m 58s}  +24.57d {+24d 34' 30"}
MOON_DIST:        59.04 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.67, 40.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      173.83,-19.19 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 295.71,18.87 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:38:18 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.576d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 07"} (J2000)
POINT_ROLL:      125.180d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27336.08 SOD {07:35:36.08} UT,   136.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.942
N_STARS:         20
X_OFFSET:        560 [pixels]
Y_OFFSET:        488 [pixels]
X_MAX:           1519 [pixels]
Y_MAX:           1447 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw01281241000msufc0136.fits
SUN_POSTN:       296.29d {+19h 45m 11s}  -21.24d {-21d 14' 12"}
SUN_DIST:        118.39 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.25d {+08h 08m 59s}  +24.57d {+24d 34' 25"}
MOON_DIST:        59.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.81,-19.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:38:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.576d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 07"} (J2000)
POINT_ROLL:      125.180d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27336.08 SOD {07:35:36.08} UT,   136.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.942
N_STARS:         20
X_OFFSET:        560 [pixels]
Y_OFFSET:        488 [pixels]
X_MAX:           1519 [pixels]
Y_MAX:           1447 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw01281241000msufc0136.fits
SUN_POSTN:       296.29d {+19h 45m 11s}  -21.24d {-21d 14' 12"}
SUN_DIST:        118.39 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.25d {+08h 09m 00s}  +24.57d {+24d 34' 24"}
MOON_DIST:        59.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.81,-19.19 [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:     Tue 14 Jan 25 07:39:36 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.576d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 07"} (J2000)
ROLL:            125.180d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27336.08 SOD {07:35:36.08} UT,   136.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     758532970
X_OFFSET:        634 [pixels]
Y_OFFSET:        796 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       794
Y_GRB_POS:       956
BINNING_INDEX:   1
IM_URL:          sw01281241000msuni0171.fits
SUN_POSTN:       296.30d {+19h 45m 11s}  -21.24d {-21d 14' 11"}
SUN_DIST:        118.39 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.26d {+08h 09m 02s}  +24.57d {+24d 34' 14"}
MOON_DIST:        59.01 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.81,-19.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:39:42 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.576d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 07"} (J2000)
ROLL:            125.180d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27336.08 SOD {07:35:36.08} UT,   136.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     758532970
X_OFFSET:        634 [pixels]
Y_OFFSET:        796 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       794
Y_GRB_POS:       956
BINNING_INDEX:   1
IM_URL:          sw01281241000msuni0171.fits
SUN_POSTN:       296.30d {+19h 45m 11s}  -21.24d {-21d 14' 11"}
SUN_DIST:        118.39 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.26d {+08h 09m 03s}  +24.57d {+24d 34' 13"}
MOON_DIST:        59.01 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.81,-19.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:41:31 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     1281241,   Seg_Num: 0
GRB_RA:          166.5767d {+11h 06m 18.40s} (J2000),
                 166.8888d {+11h 07m 33.31s} (current),
                 165.9539d {+11h 03m 48.92s} (1950)
GRB_DEC:         -15.1115d {-15d 06' 41.3"} (J2000),
                 -15.2472d {-15d 14' 49.8"} (current),
                 -14.8411d {-14d 50' 27.8"} (1950)
GRB_ERROR:       0.7 [arcsec radius, statistical only]
GRB_MAG:         20.35 +/- 0.20 [mag]
FILTER:          10, White
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27333.00 SOD {07:35:33.00} UT,   133.5 [sec] since BAT Trigger Time
SUN_POSTN:       296.30d {+19h 45m 11s}  -21.24d {-21d 14' 10"}
SUN_DIST:        118.40 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.28d {+08h 09m 07s}  +24.57d {+24d 33' 58"}
MOON_DIST:        58.98 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.63, 40.66 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      173.81,-19.17 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 2.9 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:45:20 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.577d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 08"} (J2000)
POINT_ROLL:      125.179d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27494.07 SOD {07:38:14.07} UT,   294.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.564
N_STARS:         17
X_OFFSET:        314 [pixels]
Y_OFFSET:        476 [pixels]
X_MAX:           1273 [pixels]
Y_MAX:           1435 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01281241000msufc0294.fits
SUN_POSTN:       296.30d {+19h 45m 12s}  -21.24d {-21d 14' 09"}
SUN_DIST:        118.39 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.32d {+08h 09m 16s}  +24.56d {+24d 33' 25"}
MOON_DIST:        58.96 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.82,-19.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:45:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.577d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 08"} (J2000)
POINT_ROLL:      125.179d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27494.07 SOD {07:38:14.07} UT,   294.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.564
N_STARS:         17
X_OFFSET:        314 [pixels]
Y_OFFSET:        476 [pixels]
X_MAX:           1273 [pixels]
Y_MAX:           1435 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01281241000msufc0294.fits
SUN_POSTN:       296.30d {+19h 45m 12s}  -21.24d {-21d 14' 09"}
SUN_DIST:        118.39 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.32d {+08h 09m 16s}  +24.56d {+24d 33' 23"}
MOON_DIST:        58.96 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.82,-19.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN Circular #38927
N. J. Klingler (GSFC/UMBC/CRESSTII), R. Brivio (INAF-OAB), J. J. DeLaunay (PSU), K. L. Page (U Leicester), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB), M. H. Siegel (PSU) and A. Tohuvavohu (Caltech) report on behalf of the Neil Gehrels Swift Observatory Team:
At 07:33:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250114A (trigger=1281241). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 166.590, -15.143 which is
```
   RA(J2000) = 11h 06m 22s
   Dec(J2000) = -15d 08' 34"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 50 sec. The peak count rate was ~875 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 07:35:27.7 UT, 128.3 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 166.57673, -15.11138 which is equivalent to:
```
   RA(J2000)  = 11h 06m 18.42s
   Dec(J2000) = -15d 06' 41.0"
```
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 122 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 (5.06 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.9 (+3.65/-3.04) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 4.84e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 136 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	11:06:18.43 = 166.57679
  DEC(J2000) = -15:06:41.7  = -15.11159
```
with a 90%-confidence error radius of about 0.74 arc sec. This position is 3.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 20.35 with a 1-sigma error of about 0.20. No correction has been made for the expected extinction corresponding to E(B-V) of 0.056.
Burst Advocate for this burst is N. J. Klingler (noelklin AT umbc.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:     Tue 14 Jan 25 07:53:00 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.577d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 08"} (J2000)
POINT_ROLL:      125.179d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  28072.93 SOD {07:47:52.93} UT,   873.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.867
N_STARS:         114
X_OFFSET:        74 [pixels]
Y_OFFSET:        236 [pixels]
X_MAX:           1513 [pixels]
Y_MAX:           1675 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw01281241000msufc0873.fits
SUN_POSTN:       296.31d {+19h 45m 13s}  -21.24d {-21d 14' 05"}
SUN_DIST:        118.40 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.39d {+08h 09m 34s}  +24.54d {+24d 32' 19"}
MOON_DIST:        58.90 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.82,-19.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:53:18 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.577d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 08"} (J2000)
POINT_ROLL:      125.179d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  28072.93 SOD {07:47:52.93} UT,   873.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.867
N_STARS:         114
X_OFFSET:        74 [pixels]
Y_OFFSET:        236 [pixels]
X_MAX:           1513 [pixels]
Y_MAX:           1675 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw01281241000msufc0873.fits
SUN_POSTN:       296.31d {+19h 45m 13s}  -21.24d {-21d 14' 05"}
SUN_DIST:        118.40 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.39d {+08h 09m 35s}  +24.54d {+24d 32' 17"}
MOON_DIST:        58.90 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.82,-19.19 [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:     Tue 14 Jan 25 07:54:00 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1281241,   Seg_Num: 0
GRB_RA:          166.5765d {+11h 06m 18.36s} (J2000),
                 166.8886d {+11h 07m 33.27s} (current),
                 165.9537d {+11h 03m 48.87s} (1950)
GRB_DEC:         -15.1116d {-15d 06' 41.7"} (J2000),
                 -15.2473d {-15d 14' 50.1"} (current),
                 -14.8412d {-14d 50' 28.1"} (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:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27653.00 SOD {07:40:53.00} UT,   453.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       296.31d {+19h 45m 14s}  -21.23d {-21d 14' 05"}
SUN_DIST:        118.41 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.40d {+08h 09m 36s}  +24.54d {+24d 32' 11"}
MOON_DIST:        58.87 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.63, 40.66 [deg] galactic lon,lat of the burst
ECL_COORDS:      173.81,-19.17 [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 0.11% < P(seren) < 0.58%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:56:07 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.577d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 08"} (J2000)
ROLL:            125.179d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  28072.93 SOD {07:47:52.93} UT,   873.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     758533707
X_OFFSET:        633 [pixels]
Y_OFFSET:        795 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       793
Y_GRB_POS:       955
BINNING_INDEX:   1
IM_URL:          sw01281241000msuni0908.fits
SUN_POSTN:       296.31d {+19h 45m 14s}  -21.23d {-21d 14' 04"}
SUN_DIST:        118.40 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.42d {+08h 09m 41s}  +24.53d {+24d 31' 53"}
MOON_DIST:        58.87 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.82,-19.19 [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).  
COMMENTS:        This notice was forced out after watchdog timer expiring -- most likely due to missing packet(s);  
COMMENTS:        as a consequence some of the fields may be incoorect (eg TRIGGER_NUM,RA,DEC).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:56:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.577d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 08"} (J2000)
ROLL:            125.179d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  28072.93 SOD {07:47:52.93} UT,   873.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     758533707
X_OFFSET:        633 [pixels]
Y_OFFSET:        795 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       793
Y_GRB_POS:       955
BINNING_INDEX:   1
IM_URL:          sw01281241000msuni0908.fits
SUN_POSTN:       296.31d {+19h 45m 14s}  -21.23d {-21d 14' 04"}
SUN_DIST:        118.40 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.42d {+08h 09m 42s}  +24.53d {+24d 31' 52"}
MOON_DIST:        58.87 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.63 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.82,-19.19 [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.  
COMMENTS:        This notice was forced out after watchdog timer expiring -- most likely due to missing packet(s);  
COMMENTS:        as a consequence some of the fields may be incoorect (eg TRIGGER_NUM,RA,DEC).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:46:29 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.577d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 08"} (J2000)
ROLL:            125.179d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27494.07 SOD {07:38:14.07} UT,   294.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     758533128
X_OFFSET:        634 [pixels]
Y_OFFSET:        796 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       794
Y_GRB_POS:       956
BINNING_INDEX:   1
IM_URL:          sw01281241000msuni0329.fits
SUN_POSTN:       296.30d {+19h 45m 12s}  -21.24d {-21d 14' 08"}
SUN_DIST:        118.39 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.33d {+08h 09m 19s}  +24.55d {+24d 33' 15"}
MOON_DIST:        58.95 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.82,-19.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 14 Jan 25 07:46:42 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1281241,   Seg_Num: 0
POINT_RA:        166.577d {+11h 06m 18s} (J2000)
POINT_DEC:       -15.136d {-15d 08' 08"} (J2000)
ROLL:            125.179d
IMG_START_DATE:  20689 TJD;    14 DOY;   25/01/14
IMG_START_TIME:  27494.07 SOD {07:38:14.07} UT,   294.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     758533128
X_OFFSET:        634 [pixels]
Y_OFFSET:        796 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       794
Y_GRB_POS:       956
BINNING_INDEX:   1
IM_URL:          sw01281241000msuni0329.fits
SUN_POSTN:       296.30d {+19h 45m 12s}  -21.24d {-21d 14' 08"}
SUN_DIST:        118.39 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      122.33d {+08h 09m 19s}  +24.55d {+24d 33' 13"}
MOON_DIST:        58.95 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      268.65, 40.64 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      173.82,-19.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #38928
V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 250114A ( N. J. Klingler et al., GCN 38927) errorbox 18 sec after notice time and 63 sec after trigger time at 2025-01-14 07:34:22 UT, with upper limit up to 18.2 mag. The observations began at zenith distance = 18 deg. The sun altitude is -23.6 deg.
The galactic latitude b = 41 deg., longitude l = 270 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2742671
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

      68 |         MASTER-OAFA |   C |    10 | 18.2 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #38929
J. An (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), X. Liu, Z.P. Zhu, S.Y. Fu, S.Q. Jiang, D. Xu (NAOC) report on behalf of a large collaboration:
We observed the field of GRB 250114A detected by Swift (Klingler et al., GCN 38927), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Cerro Tololo, Chile. Observations started at 07:46:08.50 UTC on 2025-01-14, i.e., 13 mins after the Swift trigger, and a series of R-band frames were obtained.
The optical afterglow by Swift/UVOT (Klingler et al., GCN 38927) is clearly detected in the stacked images. Its brightness is decaying and has r ~ 20.2 mag at a median time 14.5 mins after the Swift trigger, calibrated with PanSTARRS and not corrected for Galactic extinction.
GCN Circular #38930
D. B. Malesani (DAWN/NBI and Radboud Univ.), and L. Izzo (INAF-OACn and DARK/NBI) report:
We observed the field of GRB 250114A (Klingler et al., GCN #38927) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located at the Cerro Tololo, Chile. Observations started on 2025 January 14 at 07:48:10 UT (14.85 minutes after the GRB trigger). We obtained a series of 3x180 s images in the SDSS-r filter.
At the location of the Swift-UVOT afterglow, we detect a faint source. We measure a preliminary magnitude of r = 20.18 +/- 0.15 mag (AB), calibrated against nearby stars from the Pan-STARRS catalog. This value is consistent with TRT observations obtained at a similar epoch (An et al., GCN #38929).
This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 101004719.
GCN Circular #38931
C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina (Lomonosov MSU), O.Gress, N.Budnev(ISU), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the GRB250114A 24 sec after notice time and 63 sec after trigger time at 2025-01-14 07:34:22 UT. On our first (10s exposure) set we found 1 optical transient within Swift error-box (ra=166.588 dec=-15.1422 r=0.05).
```
 T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
      68   2025-01-14 07:34:22      10   (11h 06m 18.39s , -15d 06m 41.2s)     15.9
```
The 5-sigma upper limit has been about 17.7mag The message may be cited.
GCN Circular #38933
R. Brivio, P. D’Avanzo, M. Ferro (INAF-OAB), D.B. Malesani (DAWN/NBI and Radboud Univ.), A. Melandri (INAF-OAR), M. De Pasquale (Univ. of Messina), S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team:
We observed the field of GRB 250114A, detected by Swift (Klingler et al., GCN 38927) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2025 January 14 at 07:34:43 UT (i.e. 84 sec after the Swift trigger). We detect the counterpart in the optical and NIR images at the position of the optical afterglow (Klingler et al., GCN 38927; An et al., GCN 38929; Malesani & Izzo, GCN 38930; Francile et al., GCN 38931). From preliminary photometry, we measure:
r-i ~ 1.4 (calibrated against the Pan-STARRS catalogue), at t - t0 = 84 s;
H = 13.2 +/- 0.1 (Vega; calibrated against the 2MASS catalogue), at t - t0 = 101 s.
GCN Circular #38934
D. B. Malesani (DAWN/NBI and Radboud), A. Saccardi (CEA/Irfu), S. D. Vergani (GEPI/Obs. de Paris), P. D’Avanzo (INAF/OABr), A. de Ugarte Postigo (CNRS, OCA and LAM), K. E. Heintz (DAWN/NBI), L. Izzo (INAF/OACn and DARK/NBI), A. J. Levan (Radboud), B. Milvang-Jensen (DAWN/NBI), B. Schneider (LAM), N. R. Tanvir (Leicester), A. L. Thakur (INAF/IAPS) report on behalf of the Stargate collaboration.
We observed the optical afterglow of GRB 250114A (Klingler et al., GCN 38927; An et al., GCN 38929; Malesani & Izzo, GCN 38930; Francile et al., GCN 38931; Brivio et al., GCN 38933) using the ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph. Our spectra cover the wavelength range 3000-25000 AA, and consist of 4 exposures by 600 s each. The observation mid time was 2025 Jan 14.3549 UT (0.962 hr after the GRB).
In a 30 s image taken with the acquisition camera on Jan 14.339 UT, we detect the optical afterglow, for which we measure a magnitude r = 21.58 +- 0.12 AB (calibrated against two nearby stars from the Pan-STARRS catalog).
Continuum is clearly detected in the red end of the VIS arm, showing a strong break at 7000 AA, which we interpret as the Lyman break and the onset of the Lyman-alpha forest. From the detection of multiple absorption features, which we interpret as due to Si II 1260, Si II* 1264, O I 1302, C IV 1548,1540, Si II* 1264, and Mg II 2796,2803 (among others), we infer a redshift of z = 4.732.
An intervening system at z = 1.642 is also identified via the Mg II 2796,2803 doublet.
We acknowledge expert support from the ESO observing staff at UT3, in particular Rodrigo Palominos and Ana Jimenez.
GCN Circular #38936
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 792 s of XRT Photon Counting mode data and 1 UVOT images for GRB 250114A, 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 = 166.57609, -15.11189 which is equivalent to:
```
RA (J2000): 11h 06m 18.26s
Dec (J2000): -15d 06' 42.8"
```
with an uncertainty of 2.4 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 #38943
I. Pérez-Fournon and F. Poidevin (IAC and ULL)
We observed the field of GRB 250114A, detected by Swift BAT, XRT, and UVOT (Klingler et al., GCN 38927; Beardmore et al., GCN 38936) using one of the Las Cumbres Observatory global telescope network (LCOGT) 1-m telescopes, equipped with Sinistro cameras, at the LCOGT node at Siding Spring Observatory (Australia). The observation, a single 600-sec exposure in the SDSS i' filter, started at 2025-01-14 13:59:32 UT, i.e. ~ 6.44 hr after the Swift BAT trigger. The optical afterglow is detected at a position consistent with the UVOT coordinates (Klingler et al., GCN 38927). Me measure a magnitude of i' = 20.17 +/- 0.22, calibrated against PanSTARRS DR2 stars and not corrected for Galactic extinction.
Other groups have reported optical and near-IR detections of the afterglow: An et al. (GCN 38929), Malesani and Izzo (GCN 38930), Brivio et al. (GCN 38933) and Malesani et al. (GCN 38934). A redshift of z = 4.732 has been reported by Malesani et al. (GCN 38934).
This work makes use of observations from the Las Cumbres Observatory global telescope network (LCOGT observing programme IAC2024B-004, SGLF).
GCN Circular #38945
S. Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), C. Salvaggio (INAF-OAB), D.N. Burrows (PSU) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 8.6 ks of XRT data for GRB 250114A, from 117 s to 28.1 ks after the BAT trigger. The data comprise 317 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode.
The late-time light curve (from T0+4.6 ks) can be modelled with an initial rise, with a power-law index of alpha=-0.94 (+1.18, -0.25), followed by a break at T+8035 s to an alpha of 1.32 (+0.31, -0.29).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.09 (+/-0.03). The best-fitting absorption column is 1.8 (+/-0.9) x 10^22 cm^-2, at a redshift of 4.732, in addition to the Galactic value of 5.1 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.87 (+0.14, -0.13) and a best-fitting absorption column of 1.0 (+2.2, -1.0) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (4.1 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Galactic foreground: 5.1 x 10^20 cm^-2
Intrinsic column:    1.0 (+2.2, -1.0) x 10^22 cm^-2 at z=4.732
Photon index:	     1.87 (+0.14, -0.13)
```
If the light curve continues to decay with a power-law decay index of 1.32, the count rate at T+24 hours will be 6.8 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.4 x 10^-13 (2.8 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01281241.
This circular is an official product of the Swift-XRT team.
GCN Circular #38946
S. Antier (OCA/ICJLAB), A. Klotz (IRAP), D. Akl (AUS), S. Karpov (FZU), M. Coughlin (UMN), C. Limonta, M. Boer, Q. Andre, A. Durroux (OCA), C. Andrade (UMN), P. Hello (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/IPHC), D. Turpin (CEA-Saclay/Irfu), N. Guessoum (AUS) on behalf of the GRANDMA collaboration:
We observed the field of GRB 250114A, detected by Swift (Klingler et al., GCN 38927) using TAROT/TCH. Observations began 1 min after T0 without filter, and we took a series of one trailed image lasting 60s and then 5x30s.
We detected the optical afterglow candidate in all images. We measured the decaying flux from 15.4 +/- 0.2 r-mag after the first minute, 16.3 +/-0.1 r-mag after the second minute, and 17.4 +/- 0.2 r-mag 5 minutes post T0.
The first 60s trailed image was analysed using techniques from Klotz et al., 2006, A&A 451, L39. The data from 2 to 5 min was reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022), using Skymapper.
The light curve and its measurements can be found at : https://skyportal-icare.ijclab.in2p3.fr/public/sources/GRB250114
Our measurements are compatible with GCNs 38927, 38929, 38930, 38933, 38934, 38943.
GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).
GCN Circular #38948
Ankur Ghosh, Soebur Razzaque (CAPP, University of Johannesburg), Alexander Moskvitin, Yulia Sotnikova (SAO RAS), Naveen Dukiya (ARIES), Rahul Gupta (NASA GSFC) on behalf of a larger collaboration.
We observed the field of the GRB 250114A triggered by Swift (Klingler et al., GCN 38927) in V, r filter of the 1-meter Sinistro telescope at the Las Cumbres Observatory Global Telescope (LCOGT) node located at South African Astronomical Observatory (SAAO). The 1-m Sinistro telescope is equipped with a 4K x 4K CCD (FOV: 26 x 26 arcmin, scale: 0.39 arcsec/pixel). Observations began on January 14, 2025, starting from 6.06 hours after the GRB trigger.
We clearly detect the optical transient (OT) reported by GCNs (Beardmore et al., GCN 38936, An et al., GCN 38929; Malesani & Izzo, GCN 38930; Francile et al., GCN 38931; Brivio et al., GCN 38933, Malesani et al., GCN 38934, Pérez-Fournon & Poidevin, GCN 38943) in our V, r band image. The optical afterglow detected in our images is consistent with the UVOT coordinates (Klingler et al., GCN 38927).
```
|Date|		|UTstart|	|t-T0 (hours)|	|Exp (sec)|	|Filter|	|Magnitude|  
--------------------------------------------------------------------------------------------------     
2025-01-14	13:36:54.720	6.06		1 x 1200 	V		V = 21.88 +/- 0.52
2025-01-14	14:11:39.552	6.64		1 x 1200	r		r = 22.01 +/- 0.35
--------------------------------------------------------------------------------------------------
```
The field was calibrated against nearby APASS stars, with magnitudes converted using Lupton (2005) equations, and has not been corrected for Galactic extinction.
GCN Circular #38999
L. Rhodes (TSI/McGill), G. E. Anderson (Curtin), A. J. van der Horst (GWU), J. K. Leung (UofT/HUJI), A. Gulati (USyd), S. Chastain (UNM) on behalf of the PanRadio GRB collaboration
We observed the position of GRB 250114A (Klingler et al., GCN 38927) starting at 2025-01-16 15:53UT for 7.5 hours with the Australia Telescope Compact Array (ATCA), as part of the “PanRadio GRB” Large ATCA follow-up programme C3542 (PI. Anderson).
We detect a radio source at the reported position (Klingler et al., GCN 38927) of the afterglow with a preliminary flux density of 70uJy/beam. The rms noise in our observation is 13 uJy/beam at 7GHz.
We thank the CSIRO Space and Astronomy staff for supporting these observations.
We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO.
GCN Circular #39012
A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), R. Gupta (GSFC), N. J. Klingler (GSFC/UMBC/CRESSTII), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (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 250114A (trigger #1281241) (N. J. Klingler, et al., GCN Circ. 38927). The BAT ground-calculated position is RA, Dec = 166.572, -15.129 deg which is
```
   RA(J2000)  =  11h 06m 17.3s 
   Dec(J2000) = -15d 07' 44.5" 
```
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 21%.
The mask-weighted light curves display several pulses between T0 and T0+60 sec. There are also two additional pulses of emission starting around T0+130 and T0+260. T90 (15-350 keV) is 293.89 +- 13.45 sec (estimated error including systematics).
The time-averaged spectrum from T-8.528 to T+305.988 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.39 +- 0.62, and Epeak of 50.9 +- 6.3 keV (chi squared 44.16 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.6 +- 0.3 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T+1.72 sec in the 15-150 keV band is 1.5 +- 0.4 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.84 +- 0.11 (chi squared 66.05 for 57 d.o.f.). All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1281241

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Jochen Greiner, last update: 22-Jan-2025 [Disclaimer]