Gamma-ray Burst 241213A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Fri 13 Dec 24 02:19:18 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  GRB_RA:          116.148d {+07h 44m 35s} (J2000),
                   116.556d {+07h 46m 13s} (current),
                   115.330d {+07h 41m 19s} (1950)
  GRB_DEC:         +35.280d {+35d 16' 49"} (J2000),
                   +35.219d {+35d 13' 07"} (current),
                   +35.401d {+35d 24' 05"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       7587 [cnts]    Image_Peak=985 [image_cnts]
  TRIGGER_DUR:     1.024 [sec] 
  TRIGGER_INDEX:   147     E_range: 25-100 keV
  BKG_INTEN:       16000 [cnts]
  BKG_TIME:        8325.29 SOD {02:18:45.29} UT
  BKG_DUR:         8 [sec]
  GRB_DATE:        20657 TJD;   348 DOY;   24/12/13
  GRB_TIME:        8340.14 SOD {02:19:00.14} UT
  GRB_PHI:          91.65 [deg]
  GRB_THETA:        28.79 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     127.59 [sigma]
  IMAGE_SIGNIF:    20.83 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +0  +2  +7  +0  +0 +83  +0 
  SUN_POSTN:       260.82d {+17h 23m 17s}  -23.17d {-23d 10' 00"}
  SUN_DIST:        146.78 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.52d {+03h 10m 04s}  +21.67d {+21d 40' 13"}
  MOON_DIST:        61.02 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.49 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      111.74, 13.79 [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 = 14.06,7.83 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Fri 13 Dec 24 02:26:59 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  GRB_RA:          116.148d {+07h 44m 35s} (J2000),
                   116.556d {+07h 46m 13s} (current),
                   115.330d {+07h 41m 19s} (1950)
  GRB_DEC:         +35.280d {+35d 16' 49"} (J2000),
                   +35.219d {+35d 13' 07"} (current),
                   +35.401d {+35d 24' 05"} (1950)
  GRB_DATE:        20657 TJD;   348 DOY;   24/12/13
  GRB_TIME:        8340.14 SOD {02:19:00.14} UT
  TRIGGER_INDEX:   147
  GRB_PHI:          91.65 [deg]
  GRB_THETA:        28.79 [deg]
  DELTA_TIME:      -43.00 [sec]
  TRIGGER_DUR:     1.024 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     127.59 [sigma]
  IMAGE_SIGNIF:    20.83 [sigma]
  LC_URL:          sw01274039000msb.lc
  SUN_POSTN:       260.83d {+17h 23m 18s}  -23.17d {-23d 10' 01"}
  SUN_DIST:        146.78 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.59d {+03h 10m 23s}  +21.70d {+21d 41' 43"}
  MOON_DIST:        60.94 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.49 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      111.74, 13.79 [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 = 14.06,7.83 [deg].  
  COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Fri 13 Dec 24 02:31:58 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  POINT_RA:        116.103d {+07h 44m 25s} (J2000)
  POINT_DEC:       +35.269d {+35d 16' 10"} (J2000)
  POINT_ROLL:      78.094d
  IMG_START_DATE:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  8658.32 SOD {02:24:18.32} UT,   318.2 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        0.808
  N_STARS:         48
  X_OFFSET:        837 [pixels]
  Y_OFFSET:        367 [pixels]
  X_MAX:           1796 [pixels]
  Y_MAX:           1326 [pixels]
  DET_THRESH:      8
  PHOTO_THRESH:    3
  SL_URL:          sw01274039000msufc0318.fits
  SUN_POSTN:       260.83d {+17h 23m 19s}  -23.17d {-23d 10' 02"}
  SUN_DIST:        146.82 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.65d {+03h 10m 35s}  +21.71d {+21d 42' 41"}
  MOON_DIST:        60.86 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.45 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      111.71, 13.78 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Fri 13 Dec 24 02:32:13 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  POINT_RA:        116.103d {+07h 44m 25s} (J2000)
  POINT_DEC:       +35.269d {+35d 16' 10"} (J2000)
  ROLL:            78.094d
  IMG_START_DATE:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  8658.32 SOD {02:24:18.32} UT,   318.2 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     755749493
  X_OFFSET:        1157 [pixels]
  Y_OFFSET:        687 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1317
  Y_GRB_POS:       847
  BINNING_INDEX:   1
  IM_URL:          sw01274039000msuni0353.fits
  SUN_POSTN:       260.83d {+17h 23m 19s}  -23.17d {-23d 10' 02"}
  SUN_DIST:        146.82 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.65d {+03h 10m 36s}  +21.71d {+21d 42' 44"}
  MOON_DIST:        60.85 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.45 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      111.71, 13.78 [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:     Fri 13 Dec 24 02:32:19 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  POINT_RA:        116.103d {+07h 44m 25s} (J2000)
  POINT_DEC:       +35.269d {+35d 16' 10"} (J2000)
  ROLL:            78.094d
  IMG_START_DATE:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  8658.32 SOD {02:24:18.32} UT,   318.2 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     755749493
  X_OFFSET:        1157 [pixels]
  Y_OFFSET:        687 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1317
  Y_GRB_POS:       847
  BINNING_INDEX:   1
  IM_URL:          sw01274039000msuni0353.fits
  SUN_POSTN:       260.83d {+17h 23m 19s}  -23.17d {-23d 10' 02"}
  SUN_DIST:        146.82 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.65d {+03h 10m 36s}  +21.71d {+21d 42' 45"}
  MOON_DIST:        60.85 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.45 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      111.71, 13.78 [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:        If you have elected to receive attachments:  
  COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Fri 13 Dec 24 02:32:08 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  POINT_RA:        116.103d {+07h 44m 25s} (J2000)
  POINT_DEC:       +35.269d {+35d 16' 10"} (J2000)
  POINT_ROLL:      78.094d
  IMG_START_DATE:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  8658.32 SOD {02:24:18.32} UT,   318.2 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        0.808
  N_STARS:         48
  X_OFFSET:        837 [pixels]
  Y_OFFSET:        367 [pixels]
  X_MAX:           1796 [pixels]
  Y_MAX:           1326 [pixels]
  DET_THRESH:      8
  PHOTO_THRESH:    3
  SL_URL:          sw01274039000msufc0318.fits
  SUN_POSTN:       260.83d {+17h 23m 19s}  -23.17d {-23d 10' 02"}
  SUN_DIST:        146.82 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.65d {+03h 10m 35s}  +21.71d {+21d 42' 43"}
  MOON_DIST:        60.86 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.45 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      111.71, 13.78 [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:     Fri 13 Dec 24 02:32:50 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  GRB_RA:          116.1707d {+07h 44m 40.96s} (J2000),
                   116.5783d {+07h 46m 18.79s} (current),
                   115.3524d {+07h 41m 24.57s} (1950)
  GRB_DEC:         +35.2795d {+35d 16' 46.1"} (J2000),
                   +35.2178d {+35d 13' 04.0"} (current),
                   +35.4005d {+35d 24' 01.8"} (1950)
  GRB_ERROR:       3.5 [arcsec radius, statistical plus systematic, 90% containment]
  GRB_INTEN:       1.00e-10 [erg/cm2/sec]
  GRB_SIGNIF:      10.00 [sigma]
  IMG_START_DATE:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  8736.00 SOD {02:25:36.00} UT,   395.9 [sec] since BAT Trigger Time
  TAM[0-3]:        100.00 100.00 100.00 100.00
  AMPLIFIER:       1
  WAVEFORM:        31
  SUN_POSTN:       260.83d {+17h 23m 19s}  -23.17d {-23d 10' 02"}
  SUN_DIST:        146.77 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.65d {+03h 10m 37s}  +21.71d {+21d 42' 51"}
  MOON_DIST:        60.90 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.60, 25.51 [deg] galactic lon,lat of the burst
  ECL_COORDS:      111.76, 13.80 [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:     Fri 13 Dec 24 02:38:16 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  POINT_RA:        116.103d {+07h 44m 25s} (J2000)
  POINT_DEC:       +35.269d {+35d 16' 10"} (J2000)
  POINT_ROLL:      78.094d
  IMG_START_DATE:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  9211.50 SOD {02:33:31.50} UT,   871.4 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        3.127
  N_STARS:         70
  X_OFFSET:        597 [pixels]
  Y_OFFSET:        127 [pixels]
  X_MAX:           2036 [pixels]
  Y_MAX:           1566 [pixels]
  DET_THRESH:      15
  PHOTO_THRESH:    8
  SL_URL:          sw01274039000msufc0871.fits
  SUN_POSTN:       260.83d {+17h 23m 20s}  -23.17d {-23d 10' 03"}
  SUN_DIST:        146.83 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.71d {+03h 10m 51s}  +21.73d {+21d 43' 55"}
  MOON_DIST:        60.79 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.45 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      111.71, 13.78 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Fri 13 Dec 24 02:38:33 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  POINT_RA:        116.103d {+07h 44m 25s} (J2000)
  POINT_DEC:       +35.269d {+35d 16' 10"} (J2000)
  POINT_ROLL:      78.094d
  IMG_START_DATE:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  9211.50 SOD {02:33:31.50} UT,   871.4 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        3.127
  N_STARS:         70
  X_OFFSET:        597 [pixels]
  Y_OFFSET:        127 [pixels]
  X_MAX:           2036 [pixels]
  Y_MAX:           1566 [pixels]
  DET_THRESH:      15
  PHOTO_THRESH:    8
  SL_URL:          sw01274039000msufc0871.fits
  SUN_POSTN:       260.83d {+17h 23m 20s}  -23.17d {-23d 10' 03"}
  SUN_DIST:        146.83 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.71d {+03h 10m 51s}  +21.73d {+21d 43' 58"}
  MOON_DIST:        60.79 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.45 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      111.71, 13.78 [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:     Fri 13 Dec 24 02:39:39 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  POINT_RA:        116.103d {+07h 44m 25s} (J2000)
  POINT_DEC:       +35.269d {+35d 16' 10"} (J2000)
  ROLL:            78.094d
  IMG_START_DATE:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  9211.50 SOD {02:33:31.50} UT,   871.4 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     755750046
  X_OFFSET:        1156 [pixels]
  Y_OFFSET:        686 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1316
  Y_GRB_POS:       846
  BINNING_INDEX:   1
  IM_URL:          sw01274039000msuni0906.fits
  SUN_POSTN:       260.84d {+17h 23m 21s}  -23.17d {-23d 10' 03"}
  SUN_DIST:        146.83 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.72d {+03h 10m 54s}  +21.74d {+21d 44' 11"}
  MOON_DIST:        60.78 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.45 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      111.71, 13.78 [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:     Fri 13 Dec 24 02:38:55 UT
  NOTICE_TYPE:     Swift-XRT Position UPDATE
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  GRB_RA:          116.1714d {+07h 44m 41.13s} (J2000),
                   116.5790d {+07h 46m 18.96s} (current),
                   115.3531d {+07h 41m 24.74s} (1950)
  GRB_DEC:         +35.2794d {+35d 16' 45.8"} (J2000),
                   +35.2177d {+35d 13' 03.7"} (current),
                   +35.4004d {+35d 24' 01.4"} (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:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  8736.00 SOD {02:25:36.00} UT,   395.9 [sec] since BAT Trigger Time
  TAM[0-3]:        100.00 100.00 100.00 100.00
  AMPLIFIER:       1
  WAVEFORM:        31
  SUN_POSTN:       260.84d {+17h 23m 20s}  -23.17d {-23d 10' 03"}
  SUN_DIST:        146.77 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.72d {+03h 10m 52s}  +21.73d {+21d 44' 03"}
  MOON_DIST:        60.84 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.60, 25.51 [deg] galactic lon,lat of the burst
  ECL_COORDS:      111.76, 13.80 [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 #38547
  R. Gupta (NASA GSFC), C. Gronwall (PSU), K. L. Page (U Leicester) and T. Sakamoto (AGU) report on behalf of the Neil Gehrels Swift Observatory Team:
  At 02:19:00 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 241213A (trigger=1274039). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 116.148, +35.280 which is

     RA(J2000) = 07h 44m 35s
     Dec(J2000) = +35d 16' 49"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a bright peak with a duration of about 15 sec. The peak count rate was ~9500 counts/sec (15-350 keV), at ~0 sec after the trigger.
  The XRT began observing the field at 02:25:36.0 UT, 395.9 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 116.17145, 35.27944 which is equivalent to:

     RA(J2000)  = 07h 44m 41.15s
     Dec(J2000) = +35d 16' 46.0"
  

  with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 68 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 (6.66 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 5 (+2.07/-1.84) x 10^21 cm^-2 (90% confidence).
  UVOT took a finding chart exposure of 250 seconds with the U filter starting 318 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.060.
  Burst Advocate for this burst is R. Gupta (rahulbhu.c157 AT gmail.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Fri 13 Dec 24 02:39:53 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     1274039,   Seg_Num: 0
  POINT_RA:        116.103d {+07h 44m 25s} (J2000)
  POINT_DEC:       +35.269d {+35d 16' 10"} (J2000)
  ROLL:            78.094d
  IMG_START_DATE:  20657 TJD;   348 DOY;   24/12/13
  IMG_START_TIME:  9211.50 SOD {02:33:31.50} UT,   871.4 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     755750046
  X_OFFSET:        1156 [pixels]
  Y_OFFSET:        686 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1316
  Y_GRB_POS:       846
  BINNING_INDEX:   1
  IM_URL:          sw01274039000msuni0906.fits
  SUN_POSTN:       260.84d {+17h 23m 21s}  -23.17d {-23d 10' 03"}
  SUN_DIST:        146.83 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
  MOON_POSTN:       47.73d {+03h 10m 55s}  +21.74d {+21d 44' 14"}
  MOON_DIST:        60.78 [deg]
  MOON_ILLUM:      93 [%]
  GAL_COORDS:      184.59, 25.45 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      111.71, 13.78 [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 #38548
  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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 241213A ( R. Gupta et al., GCN 38547) errorbox 1183 sec after notice time and 1208 sec after trigger time at 2024-12-13 02:39:08 UT, with upper limit up to 17.8 mag. The observations began at zenith distance = 38 deg. The sun altitude is -20.1 deg.
  The galactic latitude b = 26 deg., longitude l = 185 deg.
  Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2708197
  We obtain a following upper limits.

  Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
  _________|_____________________|_____|_______|______|________
  
      1289 |   MASTER-Kislovodsk |  P- |   160 | 17.6 |        
      1469 |   MASTER-Kislovodsk |  P- |   520 | 17.8 |  Coadd 
      1467 |   MASTER-Kislovodsk |  P- |   180 | 16.9 |        
      1667 |   MASTER-Kislovodsk |  P- |   180 | 16.4 |        
  

  The observation and reduction will continue. The message may be cited.
• GCN Circular #38550
  O. I. Spiridonova and A. S. Moskvitin (SAO RAS), report on behalf of the GRB follow-up team.
  We observed the field of GRB 241213A (Gupta et al. GCN Circ. 38547) with the 1-m telescope of SAO RAS, Zeiss-1000 + CCD-photometer on December 12, 02:30:40--02:52:17 UT (t_mid - T0 = 1349 sec.), observations started 700 seconds after the trigger. We obtained 4 x 300 sec images in Rc band under poor seeing and weather conditions.
  Inside the XRT error circle we did not detect any significant object (as well as Lipunov et al., GCN Circ. 38548) down to the limiting magnitude of R_lim = 21.0, calibrated against nearby PS1 stars (magnitudes were converted with the Lupton 2005 equations and not corrected for the MW extinction).
• GCN Circular #38552
  J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
  Using 433 s of XRT Photon Counting mode data and 1 UVOT images for GRB 241213A, 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 = 116.16998, +35.27882 which is equivalent to:

  RA (J2000): 07h 44m 40.80s
  Dec (J2000): +35d 16' 43.8"
  

  with an uncertainty of 3.4 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 #38553
  R.Brivio, M. Ferro, P. D’Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team:
  We observed the field of GRB 241213A detected by Swift/BAT (Gupta et al., GCN 38547) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2024 December 13 at 03:50:29 UT (i.e. 1.5 hours after the Swift trigger), and lasting for about 1 hour.
  From preliminary photometry we do not detect any counterpart in the optical and NIR images at the enhanced Swift-XRT position (Osborne et al., GCN 38552) down to the following 3sigma magnitude upper limits:
  r > 19.5 (AB; calibrated against the PanSTARRS catalogue) at a mid-time of t - t0 = 2.1 hr after the trigger,
  J > 17.8 (Vega; calibrated against the 2MASS catalogue) at a mid-time of t - t0 = 2.2 hr after the trigger.
• GCN Circular #38554
  X.-Y. Zhou (PRIC), R.-Z. Li (YNAO, CAS), D.-F. Hu (PMO, CAS), S.-X. Wen, H.-W. Pan (NAO, CAS) report on behalf of the Einstein Probe team:
  We report on the detection of an X-ray transient by the Einstein Probe (EP), designated as EP241213a. The source was first detected by the Wide-field X-ray Telescope (WXT) on board EP in a single pointing observation (with an exposure time of 1.6 ks) at 2024-12-13T02:17:15 (UTC). The position of the transient is R.A. = 116.182 deg, Dec. = 35.271 deg, with an uncertainty of 2.8 arcmin. No previously known bright X-ray sources are found within the error circle around the transient position.
  The WXT spectrum of the observation can be fitted by an absorbed power law with a photon index of 2.2+/-1.4, with the NH of (5.9+/-4.8) e21 cm^-2. The derived absorbed flux in 0.5-4 keV is ~5.2e-11 ergs/s/cm^2.
  A Swift-XRT ToO proposal was submitted to observe the transient. Multi-wavelength follow-up observaitons are encouraged.
  Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
• GCN Circular #38556
  Patrizia Barria(a,b), Giulia Gianfagna(a), James Craig Rodi(a), Aishwarya Linesh Thakur(a), Luigi Piro(a), Lorenzo Natalucci(a,b) report:
  The fast X-ray transient, EP241213a, was discovered by the Einstein Probe/WXT (GCN 38554). This transient appears to be spatially coincident with GRB 241213A (BAT: GCN 38547, XRT: GCN 38552), as the XRT coordinates are consistent with the 2.8 arcmin WXT error circle. There is a temporal delay of ~ 100 s between the BAT and WXT detections. We searched for any corresponding emission in the INTEGRAL/SPI-ACS data.
  In a light curve above 80 keV, we find a pulse temporally coincident with the BAT detection (thus occurring ~ 100 s after the EP/WXT detection, assuming they are the same event), with an approximate duration of 10 sec.
  The approximate peak count rate is 80000 cts/s over a median background rate of 62500 cts/s.
  This work is based on observations with INTEGRAL, an ESA project with instruments and a science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany.
  -----

  (a) INAF/IAPS-Rome
  (b) ICSC National Research Centre for High-Performance Computing
  

• GCN Circular #38558
  R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:
  We observed the Swift GRB 241213A field (Gupta et al., GCN 38547) with the LCOGT 1-meter Sinistro instrument at the McDonald Observatory USA site, on December 13, from 06:49 to 07:19 UT (corresponding to 4.50 to 5.00 hours after the GRB trigger time) with the sdss r and i filters.
  We performed a series of 3x300s exposures in i-band and 2x300s in r-band. We do not detect a source within the Swift XRT enhanced error region (Osborne et al., GCN 38552) in either band, consistent with other optical upper limits (Lipunov et al., GCN 38548; Spiridonova et al., GCN 38550; Brivio et al., GCN 38553).
  The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference:

  r > 21.2
  i > 21.5
  

  These magnitudes are not corrected for galactic extinction.
• GCN Circular #38562
  P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
  We have analysed 4.5 ks of XRT data for GRB 241213A, from 106 s to 33.0 ks after the BAT trigger. The data comprise 275 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode.
  The light curve can be modelled with an initial power-law decay with an index of alpha=0.59 (+0.07, -0.08), followed by a break at T+680 s to an alpha of 1.20 (+0.16, -0.06).
  A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.89 (+/-0.10). The best-fitting absorption column is 3.3 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 6.7 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.85 (+/-0.14) and a best-fitting absorption column of 3.9 (+0.8, -0.7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.3 x 10^-11 (6.2 x 10^-11) erg cm^-2 count^-1.
  A summary of the PC-mode spectrum is thus:

  Total column:	     3.9 (+0.8, -0.7) x 10^21 cm^-2
  Galactic foreground: 6.7 x 10^20 cm^-2
  Excess significance: 7.4 sigma
  Photon index:	     1.85 (+/-0.14)
  

  If the light curve continues to decay with a power-law decay index of 1.20, the count rate at T+24 hours will be 0.014 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.9 x 10^-13 (8.5 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/01274039.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #38564
  S.P.R. Shilling (Lancaster) and R. Gupta (NASA GSFC) report on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 241213A 106 s after the BAT trigger (Gupta et al., GCN Circ. 38547). No optical afterglow consistent with the enhanced XRT position (Osborne et al., GCN Circ. 38552) 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           106          256          147         >20.6
  u_FC               318          568          246         >19.8
  white              106          945          259         >20.7
  v                  648         4786          236         >19.2
  b                  573          766           39         >19.0
  u                  318          742          265         >19.9
  w1                 698         5045           67         >18.7
  m2                 673         4991          216         >19.5
  w2                 624         4581          236         >19.5
  

  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.060 in the direction of the burst (Schlegel et al. 1998).
• GCN Circular #38566
  SVOM/VT commissioning team: Y. L. Qiu, H. L. Li (NAOC), Y. Wang (PMO), R.-Z. Li (YNAO), L. P. Xin, C. Wu, X. H. Han, J. Wang, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. Deng, L. Lan, X. M. Lu, R. S. Zhang, D. H. Zhao (NAOC), J. Zhang, L. J. Dan, G. Y. Zou, C. J. Wang, Y. F. Du, C. Huang (XIOPM)
  SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV)
  report on behalf of the SVOM team:
  The SVOM/VT conducted follow-up observations of the Swift-triggered GRB 241213A (Gupta et al., GCN 38547) in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channel simultaneously, from 10.636 hours to 15.7 hours after the burst.
  With the X band downlinked data, an uncatalogued optical source was detected within the errorbox of XRT (Osborne et al., GCN 38552) in VT_R stacked image, compared to the PanSTARRS catalog. The brightness of the source was estimated to be 23.8 ± 0.3 mag in AB magnitude in VT_R image at the mid time of 13.6 hours post the burst, with a total exposure time of 135*50 seconds. The source can not be detected in VT_B stacked image with 3 sigma upper limit of ~24.0 mag in AB magnitude.
  The source is located at RA, Dec = 116.17031, 35.27805, which is equivalent to:

  RA (J2000) : 07:44:40.87
  Dec (J2000): +35:16:40.99
  

  with an uncertainty of 0.5 arcsec.
  We proposed that this source is the candidate for the gamma-ray burst. Further follow-ups with SVOM/VT are scheduled to confirm the nature of the source.
  More deep follow-ups are encouraged.
  The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS.
• GCN Circular #38581
  A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
  The long-duration GRB 241213A (Swift-BAT detection: Gupta et al., GCN 38547; INTEGRAL-SPI-ACS detection: Barria et al., GCN 38556), associated with the fast X-ray transient EP241213a (Zhou et al., GCN 38554; Barria et al., GCN 38556), triggered Konus-Wind at T0=8344.058 s UT (02:19:04.058).
  The burst light curve shows a single pulse, which starts at ~T0-3.1 s and has a total duration of ~7.6 s. The emission is seen up to ~2 MeV.
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB241213_T08344/
  As observed by Konus-Wind, the burst had a fluence of 1.04(-0.07,+0.07)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.056 s, of 4.78(-1.05,+1.06)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.88(-0.17,+0.18) and Ep = 236(-24,+30) keV (chi2 = 74/77 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.6 (chi2 = 73/76 dof).
  All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
• GCN Circular #38583
  T. Sakamoto (AGU), S. D. Barthelmy (GSFC), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), (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 241213A (trigger #1274039) (Gupta, et al., GCN Circ. 38547). The BAT ground-calculated position is RA, Dec = 116.163, 35.269 deg which is

     RA(J2000)  =  07h 44m 39.2s
     Dec(J2000) = +35d 16' 06.7"
  

  with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 44%.
  The mask-weighted light curve shows a single bright episode that starts at ~T-11 s, peaks at ~T+1 s and ends at ~T+16 s. T90 (15-350 keV) is 10.3 +- 3.1 sec (estimated error including systematics).
  The time-averaged spectrum from T-10.79 to T+16.54 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.26 +- 0.06. The fluence in the 15-150 keV band is 4.1 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.24 sec in the 15-150 keV band is 10.3 +- 0.5 ph/cm2/sec. 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/1274039
• GCN Circular #38590
  M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
  The long-duration GRB 241213A (Swift/BAT detection: GCN 38547; EP/WXT detection: GCN 38554; INTEGRAL/SPI-ACS detection: GCN 38556; Konus/Wind detection: GCN 38581) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).
  The detection was confirmed at the peak time 2024-12-13 02:19:00.5 UTC. The T90 duration measured by GRBAlpha is 4.5 s and the overall significance during T90 reaches 7.6 sigma.
  The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB241213A_GCN.pdf
  All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
• GCN Circular #39685
  K. Smith (UVI), P. Gokuldass (ERAU), N. Orange (OrangeWave Innovative Science, LLC), B. Gendre (UVI), D. Morris (NASA), T. Lombardi (Eckerd College), F. George (ERAU), D. Smith (UVI), R. Querrard (UVI), and C. Watson (UVI) report:
  We observed the field of GRB241213A (Gupta et al., GCN 38547) with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 2024-12-14 starting at 7:34:05 UT (T-mid ~ T0 + 20.3 hrs). We performed a series of exposures in an R filter with a total exposure of 740s. The weather conditions were partly cloudy during the hours of observation with an average airmass of 1.1.
  We do not detect any source within the enhanced XRT position (Osborne et al. GCN 38552). This non-detection is consistent with reported detections (Qiu et al., GCN 38566) and upper limits (Spiridonova et al., GCN 38550; Shilling et al., GCN 38564; Brivio et al., GCN 38553; Strausbaugh et al., GCN 38558; and Qiu et al., GCN 38566). We report the following 3-sigma upper limit:

  T_mid                ||Exposure   ||Filter   ||Limit 
  T+20.3 h             || 740 s     || R       || > 20.3
  

  The limit is estimated from comparison to nearby USNO B1 stars and is not corrected for Galactic extinction.
  We acknowledge financial support from NASA EPSCoR award 80NNSC22M0063, NSF PAARE award 2319415, and NASA EPSCoR award 80NSSC24M0112. This message can be cited.