Gamma-ray Burst 250628A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 28 Jun 25 00:56:32 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  GRB_RA:           38.551d {+02h 34m 12s} (J2000),
                    38.809d {+02h 35m 14s} (current),
                    38.047d {+02h 32m 11s} (1950)
  GRB_DEC:         -38.081d {-38d 04' 50"} (J2000),
                   -37.970d {-37d 58' 11"} (current),
                   -38.299d {-38d 17' 56"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       5362 [cnts]    Image_Peak=219 [image_cnts]
  TRIGGER_DUR:     2.048 [sec] 
  TRIGGER_INDEX:   256     E_range: 15-50 keV
  BKG_INTEN:       51358 [cnts]
  BKG_TIME:        3324.13 SOD {00:55:24.13} UT
  BKG_DUR:         24 [sec]
  GRB_DATE:        20854 TJD;   179 DOY;   25/06/28
  GRB_TIME:        3356.71 SOD {00:55:56.71} UT
  GRB_PHI:          14.67 [deg]
  GRB_THETA:        37.56 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     12.36 [sigma]
  IMAGE_SIGNIF:    9.16 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +1  +1  +0  +0  +0 -13  +0 
  SUN_POSTN:        97.20d {+06h 28m 48s}  +23.27d {+23d 16' 13"}
  SUN_DIST:         82.15 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.24d {+08h 56m 58s}  +20.63d {+20d 37' 57"}
  MOON_DIST:       106.66 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.39,-65.86 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:       18.40,-49.55 [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 = 124.13,20.36 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 28 Jun 25 00:58:36 UT
  NOTICE_TYPE:     Swift-XRT Image
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  GRB_RA:           38.5534d {+02h 34m 12.8s} (J2000),
                    38.8106d {+02h 35m 14.5s} (current),
                    38.0486d {+02h 32m 11.6s} (1950)
  GRB_DEC:         -38.0785d {-38d 04' 42.5"} (J2000),
                   -37.9677d {-37d 58' 03.8"} (current),
                   -38.2970d {-38d 17' 49.1"} (1950)
  GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       46 [cnts]
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3477.79 SOD {00:57:57.79} UT,   121.1 [sec] since BAT Trigger Time
  CENTROID_X:      280.59,  raw= 281  [pixels]
  CENTROID_Y:      299.96,  raw= 300  [pixels]
  ROLL:            52.35 [deg]
  GAIN:            1
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   2.98
  GRB_POS_XRT_Z:   -73.09
  IMAGE_URL:       sw01328546000msxps_rw.img
  SUN_POSTN:        97.20d {+06h 28m 48s}  +23.27d {+23d 16' 13"}
  SUN_DIST:         82.15 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.26d {+08h 57m 03s}  +20.63d {+20d 37' 33"}
  MOON_DIST:       106.67 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.38,-65.86 [deg] galactic lon,lat of the burst
  ECL_COORDS:       18.40,-49.55 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Image.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 28 Jun 25 00:58:39 UT
  NOTICE_TYPE:     Swift-XRT Processed Image
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  GRB_RA:           38.5534d {+02h 34m 12.8s} (J2000),
                    38.8106d {+02h 35m 14.5s} (current),
                    38.0486d {+02h 32m 11.6s} (1950)
  GRB_DEC:         -38.0785d {-38d 04' 42.5"} (J2000),
                   -37.9677d {-37d 58' 03.8"} (current),
                   -38.2970d {-38d 17' 49.1"} (1950)
  GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       46 [cnts]
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3477.79 SOD {00:57:57.79} UT,   121.1 [sec] since BAT Trigger Time
  CENTROID_X:      280.59,  raw= 281  [pixels]
  CENTROID_Y:      299.96,  raw= 300  [pixels]
  ROLL:            52.35 [deg]
  GAIN:            1
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   2.98
  GRB_POS_XRT_Z:   -73.09
  IMAGE_URL:       sw01328546000msxps_rw.img
  SUN_POSTN:        97.20d {+06h 28m 48s}  +23.27d {+23d 16' 13"}
  SUN_DIST:         82.15 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.26d {+08h 57m 03s}  +20.63d {+20d 37' 33"}
  MOON_DIST:       106.67 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.38,-65.86 [deg] galactic lon,lat of the burst
  ECL_COORDS:       18.40,-49.55 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Processed Image.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 28 Jun 25 00:58:26 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  GRB_RA:           38.5534d {+02h 34m 12.81s} (J2000),
                    38.8106d {+02h 35m 14.55s} (current),
                    38.0486d {+02h 32m 11.66s} (1950)
  GRB_DEC:         -38.0785d {-38d 04' 42.5"} (J2000),
                   -37.9677d {-37d 58' 03.8"} (current),
                   -38.2970d {-38d 17' 49.1"} (1950)
  GRB_ERROR:       5.6 [arcsec radius, statistical plus systematic, 90% containment]
  GRB_INTEN:       9.47e-10 [erg/cm2/sec]
  GRB_SIGNIF:      6.78 [sigma]
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3477.79 SOD {00:57:57.79} UT,   121.1 [sec] since BAT Trigger Time
  TAM[0-3]:        327.66 237.11 261.54 243.72
  AMPLIFIER:       2
  WAVEFORM:        134
  SUN_POSTN:        97.20d {+06h 28m 48s}  +23.27d {+23d 16' 13"}
  SUN_DIST:         82.15 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.26d {+08h 57m 02s}  +20.63d {+20d 37' 35"}
  MOON_DIST:       106.67 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.38,-65.86 [deg] galactic lon,lat of the burst
  ECL_COORDS:       18.40,-49.55 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Coordinates.  
  COMMENTS:        The XRT position is 0.17 arcmin from the BAT position.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 28 Jun 25 01:00:21 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  GRB_RA:           38.551d {+02h 34m 12s} (J2000),
                    38.809d {+02h 35m 14s} (current),
                    38.047d {+02h 32m 11s} (1950)
  GRB_DEC:         -38.081d {-38d 04' 50"} (J2000),
                   -37.970d {-37d 58' 11"} (current),
                   -38.299d {-38d 17' 56"} (1950)
  GRB_DATE:        20854 TJD;   179 DOY;   25/06/28
  GRB_TIME:        3356.71 SOD {00:55:56.71} UT
  TRIGGER_INDEX:   256
  GRB_PHI:          14.67 [deg]
  GRB_THETA:        37.56 [deg]
  DELTA_TIME:      -56.00 [sec]
  TRIGGER_DUR:     2.048 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     12.36 [sigma]
  IMAGE_SIGNIF:    9.16 [sigma]
  LC_URL:          sw01328546000msb.lc
  SUN_POSTN:        97.20d {+06h 28m 48s}  +23.27d {+23d 16' 12"}
  SUN_DIST:         82.16 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.28d {+08h 57m 07s}  +20.62d {+20d 37' 13"}
  MOON_DIST:       106.68 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.39,-65.86 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:       18.40,-49.55 [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 = 124.13,20.36 [deg].  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 28 Jun 25 01:02:44 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  POINT_RA:         38.534d {+02h 34m 08s} (J2000)
  POINT_DEC:       -38.092d {-38d 05' 29"} (J2000)
  POINT_ROLL:      52.354d
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3486.46 SOD {00:58:06.46} UT,   129.8 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        6.576
  N_STARS:         29
  X_OFFSET:        592 [pixels]
  Y_OFFSET:        496 [pixels]
  X_MAX:           1551 [pixels]
  Y_MAX:           1455 [pixels]
  DET_THRESH:      22
  PHOTO_THRESH:    13
  SL_URL:          sw01328546000msufc0129.fits
  SUN_POSTN:        97.20d {+06h 28m 49s}  +23.27d {+23d 16' 12"}
  SUN_DIST:         82.17 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.30d {+08h 57m 12s}  +20.61d {+20d 36' 46"}
  MOON_DIST:       106.71 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.42,-65.87 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:       18.37,-49.56 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 28 Jun 25 01:02:51 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  POINT_RA:         38.534d {+02h 34m 08s} (J2000)
  POINT_DEC:       -38.092d {-38d 05' 29"} (J2000)
  POINT_ROLL:      52.354d
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3486.46 SOD {00:58:06.46} UT,   129.8 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        6.576
  N_STARS:         29
  X_OFFSET:        592 [pixels]
  Y_OFFSET:        496 [pixels]
  X_MAX:           1551 [pixels]
  Y_MAX:           1455 [pixels]
  DET_THRESH:      22
  PHOTO_THRESH:    13
  SL_URL:          sw01328546000msufc0129.fits
  SUN_POSTN:        97.20d {+06h 28m 49s}  +23.27d {+23d 16' 12"}
  SUN_DIST:         82.17 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.30d {+08h 57m 12s}  +20.61d {+20d 36' 44"}
  MOON_DIST:       106.71 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.42,-65.87 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:       18.37,-49.56 [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:     Sat 28 Jun 25 01:04:59 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  POINT_RA:         38.534d {+02h 34m 08s} (J2000)
  POINT_DEC:       -38.092d {-38d 05' 29"} (J2000)
  ROLL:            52.354d
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3486.46 SOD {00:58:06.46} UT,   129.8 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     772765122
  X_OFFSET:        923 [pixels]
  Y_OFFSET:        806 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1083
  Y_GRB_POS:       966
  BINNING_INDEX:   1
  IM_URL:          sw01328546000msuni0165.fits
  SUN_POSTN:        97.20d {+06h 28m 49s}  +23.27d {+23d 16' 12"}
  SUN_DIST:         82.17 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.32d {+08h 57m 17s}  +20.61d {+20d 36' 19"}
  MOON_DIST:       106.72 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.42,-65.87 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:       18.37,-49.56 [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:     Sat 28 Jun 25 01:05:14 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  POINT_RA:         38.534d {+02h 34m 08s} (J2000)
  POINT_DEC:       -38.092d {-38d 05' 29"} (J2000)
  ROLL:            52.354d
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3486.46 SOD {00:58:06.46} UT,   129.8 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     772765122
  X_OFFSET:        923 [pixels]
  Y_OFFSET:        806 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1083
  Y_GRB_POS:       966
  BINNING_INDEX:   1
  IM_URL:          sw01328546000msuni0165.fits
  SUN_POSTN:        97.20d {+06h 28m 49s}  +23.27d {+23d 16' 12"}
  SUN_DIST:         82.17 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.32d {+08h 57m 18s}  +20.60d {+20d 36' 16"}
  MOON_DIST:       106.72 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.42,-65.87 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:       18.37,-49.56 [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:     Sat 28 Jun 25 01:11:25 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  POINT_RA:         38.533d {+02h 34m 08s} (J2000)
  POINT_DEC:       -38.091d {-38d 05' 25"} (J2000)
  POINT_ROLL:      52.355d
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3698.34 SOD {01:01:38.34} UT,   341.6 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        3.030
  N_STARS:         28
  X_OFFSET:        603 [pixels]
  Y_OFFSET:        486 [pixels]
  X_MAX:           1562 [pixels]
  Y_MAX:           1445 [pixels]
  DET_THRESH:      14
  PHOTO_THRESH:    8
  SL_URL:          sw01328546000msufc0341.fits
  SUN_POSTN:        97.21d {+06h 28m 50s}  +23.27d {+23d 16' 11"}
  SUN_DIST:         82.18 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.38d {+08h 57m 32s}  +20.58d {+20d 35' 05"}
  MOON_DIST:       106.75 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.42,-65.87 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:       18.37,-49.56 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 28 Jun 25 01:11:39 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  POINT_RA:         38.533d {+02h 34m 08s} (J2000)
  POINT_DEC:       -38.091d {-38d 05' 25"} (J2000)
  POINT_ROLL:      52.355d
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3698.34 SOD {01:01:38.34} UT,   341.6 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        3.030
  N_STARS:         28
  X_OFFSET:        603 [pixels]
  Y_OFFSET:        486 [pixels]
  X_MAX:           1562 [pixels]
  Y_MAX:           1445 [pixels]
  DET_THRESH:      14
  PHOTO_THRESH:    8
  SL_URL:          sw01328546000msufc0341.fits
  SUN_POSTN:        97.21d {+06h 28m 50s}  +23.27d {+23d 16' 11"}
  SUN_DIST:         82.18 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.38d {+08h 57m 32s}  +20.58d {+20d 35' 02"}
  MOON_DIST:       106.76 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.42,-65.87 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:       18.37,-49.56 [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:     Sat 28 Jun 25 01:12:01 UT
  NOTICE_TYPE:     Swift-XRT Position UPDATE
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  GRB_RA:           38.5523d {+02h 34m 12.55s} (J2000),
                    38.8095d {+02h 35m 14.28s} (current),
                    38.0475d {+02h 32m 11.40s} (1950)
  GRB_DEC:         -38.0790d {-38d 04' 44.4"} (J2000),
                   -37.9682d {-37d 58' 05.6"} (current),
                   -38.2975d {-38d 17' 50.9"} (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:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3533.00 SOD {00:58:53.00} UT,   176.3 [sec] since BAT Trigger Time
  TAM[0-3]:        100.00 100.00 100.00 100.00
  AMPLIFIER:       1
  WAVEFORM:        31
  SUN_POSTN:        97.21d {+06h 28m 50s}  +23.27d {+23d 16' 11"}
  SUN_DIST:         82.16 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.39d {+08h 57m 33s}  +20.58d {+20d 34' 58"}
  MOON_DIST:       106.74 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.38,-65.86 [deg] galactic lon,lat of the burst
  ECL_COORDS:       18.40,-49.55 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Coordinates.  
  COMMENTS:        This Notice was ground-generated -- not flight-generated.  
  COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
  COMMENTS:        TAM values, flux and significance fields are not valid.  
  COMMENTS:        This position was automatically generated on the ground using  
  COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
  COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
  COMMENTS:        This position was enhanced using UVOT field astrometry.  
  COMMENTS:        The probability that this is a serendipitous source in the  
  COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 28 Jun 25 01:13:07 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  POINT_RA:         38.533d {+02h 34m 08s} (J2000)
  POINT_DEC:       -38.091d {-38d 05' 25"} (J2000)
  ROLL:            52.355d
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3698.34 SOD {01:01:38.34} UT,   341.6 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     772765334
  X_OFFSET:        923 [pixels]
  Y_OFFSET:        806 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1083
  Y_GRB_POS:       966
  BINNING_INDEX:   1
  IM_URL:          sw01328546000msuni0377.fits
  SUN_POSTN:        97.21d {+06h 28m 50s}  +23.27d {+23d 16' 11"}
  SUN_DIST:         82.18 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.40d {+08h 57m 36s}  +20.58d {+20d 34' 45"}
  MOON_DIST:       106.76 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.42,-65.87 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:       18.37,-49.56 [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:     Sat 28 Jun 25 01:12:53 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     1328546,   Seg_Num: 0
  POINT_RA:         38.533d {+02h 34m 08s} (J2000)
  POINT_DEC:       -38.091d {-38d 05' 25"} (J2000)
  ROLL:            52.355d
  IMG_START_DATE:  20854 TJD;   179 DOY;   25/06/28
  IMG_START_TIME:  3698.34 SOD {01:01:38.34} UT,   341.6 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     772765334
  X_OFFSET:        923 [pixels]
  Y_OFFSET:        806 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1083
  Y_GRB_POS:       966
  BINNING_INDEX:   1
  IM_URL:          sw01328546000msuni0377.fits
  SUN_POSTN:        97.21d {+06h 28m 50s}  +23.27d {+23d 16' 11"}
  SUN_DIST:         82.18 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
  MOON_POSTN:      134.40d {+08h 57m 35s}  +20.58d {+20d 34' 48"}
  MOON_DIST:       106.76 [deg]
  MOON_ILLUM:      9 [%]
  GAL_COORDS:      246.42,-65.87 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:       18.37,-49.56 [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 Circular #40853
  M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), J. J. DeLaunay (PSU), R. Gupta (NASA GSFC) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team:
  At 00:55:56.71 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250628A (trigger=1328546). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 38.551, -38.081 which is

     RA(J2000) = 02h 34m 12s
     Dec(J2000) = -38d 04' 50"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed two emission pulses with the first brighter pulse starting from T0-20 sec to T0+20 sec and the second fainter pulse from T0+25 end T0+60 sec. The peak count rate was ~1066 counts/sec (15-350 keV), at ~1 sec after the trigger.
  The XRT began observing the field at 00:57:57.7 UT, 121.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source with an enhanced position: RA, Dec 38.55240, -38.07909 which is equivalent to:

     RA(J2000)  = 02h 34m 12.58s
     Dec(J2000) = -38d 04' 44.7"
  

  with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 7.9 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 (2.30 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.1 (+4.01/-3.17) x 10^21 cm^-2 (90% confidence).
  The initial flux in the 2.5 s image was 9.47e-10 erg cm^-2 s^-1 (0.2-10 keV).
  UVOT took a finding chart exposure of 150 seconds with the White filter starting 129 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 100% 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 0.023.
  Burst Advocate for this burst is M. Ferro (matteo.ferro AT inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
• GCN Circular #40854
  P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
  Using 1647 s of XRT Photon Counting mode data and 4 UVOT images for GRB 250628A, 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 = 38.55311, -38.07894 which is equivalent to:

  RA (J2000): 02h 34m 12.75s
  Dec (J2000): -38d 04' 44.2"
  

  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 #40855
  V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO), 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 250628A ( M. Ferro et al., GCN 40853) errorbox 17683 sec after notice time and 17722 sec after trigger time at 2025-06-28 05:51:18 UT, with upper limit up to 16.0 mag. The observations began at zenith distance = 81 deg. The sun altitude is -72.0 deg.
  The galactic latitude b = -66 deg., longitude l = 246 deg.
  Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2918453
  We obtain a following upper limits.

  Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
  _________|_____________________|_____|_______|______|________
  
     17812 |         MASTER-OAFA |   C |   180 | 16.0 |        
  

  Filter C is a clear (unfiltred) band.
  The observation and reduction will continue. The message may be cited.
• GCN Circular #40857
  A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU), M.A. Williams (PSU) and P.A. Evans report on behalf of the Swift-XRT team:
  We have analysed 8.2 ks of XRT data for GRB 250628A, from 127 s to 27.6 ks after the trigger. The data comprise 47 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode.
  The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=5.0 (+0.6, -0.5). At T+358 s the decay flattens to an alpha of -0.01 (+0.11, -0.13) before breaking again at T+14.4 ks to a final decay with index alpha=2.6 (+/-0.6).
  A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.92 (+0.17, -0.16). The best-fitting absorption column is 3.2 (+0.8, -0.7) x 10^21 cm^-2, in excess of the Galactic value of 2.3 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 4.0 x 10^-11 (5.8 x 10^-11) erg cm^-2 count^-1.
  A summary of the PC-mode spectrum is thus:

  Total column:	     3.2 (+0.8, -0.7) x 10^21 cm^-2
  Galactic foreground: 2.3 x 10^20 cm^-2
  Excess significance: 6.8 sigma
  Photon index:	     1.92 (+0.17, -0.16)
  

  If the light curve continues to decay with a power-law decay index of 2.6, the count rate at T+24 hours will be 1.6 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.5 x 10^-14 (9.3 x 10^-14) erg cm^-2 s^-1.
  The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01328546.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #40858
  Paul Kuin (MSSL/UCL) and M Ferro (INAF-OAB) report on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 250628A 130 s after the BAT trigger (Ferro et al., GCN Circ. 40853). No optical afterglow consistent with the enhanced XRT position (Evans et al. GCN Circ. 40854) 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           130          280          147         >20.8
  u_FC               342          591          246         >19.3
  white              130          641          167         >20.8
  v                  671          691           19         >17.8
  b                  597          617           19         >18.5
  u                  342          591          246         >19.3
  w1                 720          740           19         >18.2
  

  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.023 in the direction of the burst (Schlegel et al. 1998).
• GCN Circular #40859
  R. Brivio (INAF-OABr), A. Martin-Carrillo (UCD), G. Corcoran (UCD), L. Izzo (INAF/OAC), A. Rossi (INAF/OAS), D. B. Malesani (DAWN/NBI and Radboud), N. R. Tanvir (Leicester) report on behalf of the Stargate collaboration:
  We observed the field of GRB 250628A detected by Swift/BAT (Ferro et al., GCN 40853) using the ESO VLT UT3 (Melipal) equipped with the X-shooter acquisition camera.
  A short sequence of imaging was secured in the r (3x30 s), g (3x40 s), and z (3x60 s) bands. No afterglow is detected within the Swift/XRT enhanced error region (Evans et al., GCN 40854). From preliminary analysis, we measure the following 3sigma upper limits, calibrated against nearby stars from the Legacy Survey (DR9):

  g > 23.7 (AB) on Jun 28 at 08:51:48 UT (7.93 hr after the GRB trigger),
  r > 23.6 (AB) on Jun 28 at 08:45:04 UT (7.82 hr after the GRB trigger),
  z > 22.8 (AB) on Jun 28 at 08:48:21 UT (7.87 hr after the GRB trigger).
  

  We note the detection of significant excess absorption in the X-ray spectrum (Evans, GCN 40857; https://www.swift.ac.uk/xrt_spectra/01328546/). This argues against a high-redshift origin for GRB 250628A and likely indicates some dust extinction.
  We acknowledge excellent support from the ESO observing staff in Paranal, in particular Boris Häußler.
• GCN Circular #40865
  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 250628A detected by Swift/BAT (Ferro et al., GCN 40853) with the REM 60 cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, and H bands, started on 2025 June 28 at 06:17:20 UT (i.e. 5.4 hr after the burst), and lasted for about 1 hour. From preliminary inspection, we do not detect any possible counterpart within the Swift/XRT error region (Evans et al., GCN 40854) down to the following 3sigma limits:
  r > 20.1 (AB; calibrated against the SkyMapper catalogue), at a mid-time of 5.9 hr after the trigger;
  H > 14.8 (Vega; calibrated against the 2MASS catalogue), at a mid-time of 5.4 hr after the trigger.
• GCN Circular #41081
  C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), M. Ferro (INAF-OAB), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), 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-240 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 250628A (trigger #1328546) (Ferro, et al., GCN Circ. 40853). The BAT ground-calculated position is RA, Dec = 38.539, -38.082 deg which is

     RA(J2000)  =  02h 34m 09.3s
     Dec(J2000) = -38d 04' 54.3"
  

  with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 51%.
  The mask-weighted light curve shows a double-peak structure that starts at ~T-9 s, peaks at ~T+1 s, and ends at ~T+70 s. T90 (15-350 keV) is 64 +- 11 sec (estimated error including systematics).
  The time-averaged spectrum from T-9.42 to T+68.56 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.99 +- 0.12. The fluence in the 15-150 keV band is 1.9 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.10 sec in the 15-150 keV band is 1.2 +- 0.2 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/1328546