Gamma-ray Burst 250807B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:44:26 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  GRB_RA:           15.585d {+01h 02m 21s} (J2000),
                    15.849d {+01h 03m 24s} (current),
                    15.069d {+01h 00m 16s} (1950)
  GRB_DEC:         -59.094d {-59d 05' 37"} (J2000),
                   -58.957d {-58d 57' 24"} (current),
                   -59.363d {-59d 21' 44"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       0 [cnts]    Image_Peak=1715 [image_cnts]
  TRIGGER_DUR:     64.000 [sec] 
  TRIGGER_INDEX:   20000     E_range: 15-50 keV
  BKG_INTEN:       0 [cnts]
  BKG_TIME:        0.00 SOD {00:00:00.00} UT
  BKG_DUR:         0 [sec]
  GRB_DATE:        20894 TJD;   219 DOY;   25/08/07
  GRB_TIME:        56587.89 SOD {15:43:07.89} UT
  GRB_PHI:          52.27 [deg]
  GRB_THETA:        23.69 [deg]
  SOLN_STATUS:     0x13
  RATE_SIGNIF:     0.00 [sigma]
  IMAGE_SIGNIF:    9.22 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +6  +1  +0  +0  +0 +50  +0 
  SUN_POSTN:       137.85d {+09h 11m 25s}  +16.22d {+16d 13' 07"}
  SUN_DIST:        120.11 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.55d {+19h 50m 11s}  -25.34d {-25d 20' 25"}
  MOON_DIST:        62.54 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.29,-57.98 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      336.54,-57.36 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Coordinates.  
  COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
  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 = 216.58,6.74 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:46:08 UT
  NOTICE_TYPE:     Swift-XRT Processed Image
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  GRB_RA:           15.6378d {+01h 02m 33.0s} (J2000),
                    15.9012d {+01h 03m 36.2s} (current),
                    15.1214d {+01h 00m 29.1s} (1950)
  GRB_DEC:         -59.1186d {-59d 07' 06.9"} (J2000),
                   -58.9814d {-58d 58' 53.2"} (current),
                   -59.3870d {-59d 23' 13.3"} (1950)
  GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       44 [cnts]
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56732.39 SOD {15:45:32.39} UT,   144.5 [sec] since BAT Trigger Time
  CENTROID_X:      250.20,  raw= 250  [pixels]
  CENTROID_Y:      269.79,  raw= 270  [pixels]
  ROLL:            110.08 [deg]
  GAIN:            1
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   -68.13
  GRB_POS_XRT_Z:   -144.72
  IMAGE_URL:       sw01340561000msxps_rw.img
  SUN_POSTN:       137.85d {+09h 11m 25s}  +16.22d {+16d 13' 06"}
  SUN_DIST:        120.08 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.56d {+19h 50m 15s}  -25.34d {-25d 20' 12"}
  MOON_DIST:        62.56 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.24,-57.95 [deg] galactic lon,lat of the burst
  ECL_COORDS:      336.55,-57.40 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Processed Image.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:45:56 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  GRB_RA:           15.6378d {+01h 02m 33.07s} (J2000),
                    15.9012d {+01h 03m 36.29s} (current),
                    15.1214d {+01h 00m 29.13s} (1950)
  GRB_DEC:         -59.1186d {-59d 07' 06.9"} (J2000),
                   -58.9814d {-58d 58' 53.2"} (current),
                   -59.3870d {-59d 23' 13.3"} (1950)
  GRB_ERROR:       5.6 [arcsec radius, statistical plus systematic, 90% containment]
  GRB_INTEN:       1.02e-09 [erg/cm2/sec]
  GRB_SIGNIF:      6.63 [sigma]
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56732.39 SOD {15:45:32.39} UT,   144.5 [sec] since BAT Trigger Time
  TAM[0-3]:        327.62 237.10 261.56 243.70
  AMPLIFIER:       2
  WAVEFORM:        134
  SUN_POSTN:       137.85d {+09h 11m 25s}  +16.22d {+16d 13' 06"}
  SUN_DIST:        120.08 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.56d {+19h 50m 14s}  -25.34d {-25d 20' 13"}
  MOON_DIST:        62.56 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.24,-57.95 [deg] galactic lon,lat of the burst
  ECL_COORDS:      336.55,-57.40 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Coordinates.  
  COMMENTS:        The XRT position is 2.18 arcmin from the BAT position.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:46:06 UT
  NOTICE_TYPE:     Swift-XRT Image
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  GRB_RA:           15.6378d {+01h 02m 33.0s} (J2000),
                    15.9012d {+01h 03m 36.2s} (current),
                    15.1214d {+01h 00m 29.1s} (1950)
  GRB_DEC:         -59.1186d {-59d 07' 06.9"} (J2000),
                   -58.9814d {-58d 58' 53.2"} (current),
                   -59.3870d {-59d 23' 13.3"} (1950)
  GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       44 [cnts]
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56732.39 SOD {15:45:32.39} UT,   144.5 [sec] since BAT Trigger Time
  CENTROID_X:      250.20,  raw= 250  [pixels]
  CENTROID_Y:      269.79,  raw= 270  [pixels]
  ROLL:            110.08 [deg]
  GAIN:            1
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   -68.13
  GRB_POS_XRT_Z:   -144.72
  IMAGE_URL:       sw01340561000msxps_rw.img
  SUN_POSTN:       137.85d {+09h 11m 25s}  +16.22d {+16d 13' 06"}
  SUN_DIST:        120.08 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.56d {+19h 50m 15s}  -25.34d {-25d 20' 12"}
  MOON_DIST:        62.56 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.24,-57.95 [deg] galactic lon,lat of the burst
  ECL_COORDS:      336.55,-57.40 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Image.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:47:19 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  GRB_RA:           15.585d {+01h 02m 21s} (J2000),
                    15.849d {+01h 03m 24s} (current),
                    15.069d {+01h 00m 16s} (1950)
  GRB_DEC:         -59.094d {-59d 05' 37"} (J2000),
                   -58.957d {-58d 57' 24"} (current),
                   -59.363d {-59d 21' 44"} (1950)
  GRB_DATE:        20894 TJD;   219 DOY;   25/08/07
  GRB_TIME:        56587.89 SOD {15:43:07.89} UT
  TRIGGER_INDEX:   20000
  GRB_PHI:          52.27 [deg]
  GRB_THETA:        23.69 [deg]
  DELTA_TIME:      0.00 [sec]
  TRIGGER_DUR:     64.000 [sec] 
  SOLN_STATUS:     0x13
  RATE_SIGNIF:     0.00 [sigma]
  IMAGE_SIGNIF:    9.22 [sigma]
  LC_URL:          sw01340561000msb.lc
  SUN_POSTN:       137.86d {+09h 11m 25s}  +16.22d {+16d 13' 05"}
  SUN_DIST:        120.11 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.57d {+19h 50m 18s}  -25.33d {-25d 20' 03"}
  MOON_DIST:        62.53 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.29,-57.98 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      336.54,-57.36 [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 an image 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 = 216.58,6.74 [deg].  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:48:41 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  POINT_RA:         15.577d {+01h 02m 18s} (J2000)
  POINT_DEC:       -59.087d {-59d 05' 13"} (J2000)
  POINT_ROLL:      110.082d
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56741.50 SOD {15:45:41.50} UT,   153.6 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        3.793
  N_STARS:         46
  X_OFFSET:        536 [pixels]
  Y_OFFSET:        568 [pixels]
  X_MAX:           1495 [pixels]
  Y_MAX:           1527 [pixels]
  DET_THRESH:      16
  PHOTO_THRESH:    9
  SL_URL:          sw01340561000msufc0153.fits
  SUN_POSTN:       137.86d {+09h 11m 26s}  +16.22d {+16d 13' 04"}
  SUN_DIST:        120.12 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.59d {+19h 50m 21s}  -25.33d {-25d 19' 52"}
  MOON_DIST:        62.52 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.30,-57.99 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      336.55,-57.35 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:48:53 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  POINT_RA:         15.577d {+01h 02m 18s} (J2000)
  POINT_DEC:       -59.087d {-59d 05' 13"} (J2000)
  POINT_ROLL:      110.082d
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56741.50 SOD {15:45:41.50} UT,   153.6 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        3.793
  N_STARS:         46
  X_OFFSET:        536 [pixels]
  Y_OFFSET:        568 [pixels]
  X_MAX:           1495 [pixels]
  Y_MAX:           1527 [pixels]
  DET_THRESH:      16
  PHOTO_THRESH:    9
  SL_URL:          sw01340561000msufc0153.fits
  SUN_POSTN:       137.86d {+09h 11m 26s}  +16.22d {+16d 13' 04"}
  SUN_DIST:        120.12 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.59d {+19h 50m 21s}  -25.33d {-25d 19' 51"}
  MOON_DIST:        62.52 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.30,-57.99 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      336.55,-57.35 [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:     Thu 07 Aug 25 15:51:30 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  POINT_RA:         15.577d {+01h 02m 18s} (J2000)
  POINT_DEC:       -59.087d {-59d 05' 13"} (J2000)
  ROLL:            110.082d
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56741.50 SOD {15:45:41.50} UT,   153.6 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     776274377
  X_OFFSET:        1112 [pixels]
  Y_OFFSET:        861 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1272
  Y_GRB_POS:       1021
  BINNING_INDEX:   1
  IM_URL:          sw01340561000msuni0190.fits
  SUN_POSTN:       137.86d {+09h 11m 26s}  +16.22d {+16d 13' 02"}
  SUN_DIST:        120.12 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.61d {+19h 50m 27s}  -25.33d {-25d 19' 30"}
  MOON_DIST:        62.51 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.30,-57.99 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      336.55,-57.35 [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:     Thu 07 Aug 25 15:51:52 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  POINT_RA:         15.579d {+01h 02m 19s} (J2000)
  POINT_DEC:       -59.087d {-59d 05' 13"} (J2000)
  POINT_ROLL:      110.080d
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56900.74 SOD {15:48:20.74} UT,   312.8 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        0.211
  N_STARS:         8
  X_OFFSET:        792 [pixels]
  Y_OFFSET:        541 [pixels]
  X_MAX:           1751 [pixels]
  Y_MAX:           1500 [pixels]
  DET_THRESH:      5
  PHOTO_THRESH:    2
  SL_URL:          sw01340561000msufc0312.fits
  SUN_POSTN:       137.86d {+09h 11m 26s}  +16.22d {+16d 13' 01"}
  SUN_DIST:        120.12 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.62d {+19h 50m 28s}  -25.32d {-25d 19' 28"}
  MOON_DIST:        62.51 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.30,-57.99 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      336.55,-57.36 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:52:00 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  POINT_RA:         15.579d {+01h 02m 19s} (J2000)
  POINT_DEC:       -59.087d {-59d 05' 13"} (J2000)
  POINT_ROLL:      110.080d
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56900.74 SOD {15:48:20.74} UT,   312.8 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        0.211
  N_STARS:         8
  X_OFFSET:        792 [pixels]
  Y_OFFSET:        541 [pixels]
  X_MAX:           1751 [pixels]
  Y_MAX:           1500 [pixels]
  DET_THRESH:      5
  PHOTO_THRESH:    2
  SL_URL:          sw01340561000msufc0312.fits
  SUN_POSTN:       137.86d {+09h 11m 26s}  +16.22d {+16d 13' 01"}
  SUN_DIST:        120.12 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.62d {+19h 50m 28s}  -25.32d {-25d 19' 27"}
  MOON_DIST:        62.51 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.30,-57.99 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      336.55,-57.36 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  COMMENTS:        If you have elected to receive attachments:  
  COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:51:38 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  POINT_RA:         15.577d {+01h 02m 18s} (J2000)
  POINT_DEC:       -59.087d {-59d 05' 13"} (J2000)
  ROLL:            110.082d
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56741.50 SOD {15:45:41.50} UT,   153.6 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     776274377
  X_OFFSET:        1112 [pixels]
  Y_OFFSET:        861 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1272
  Y_GRB_POS:       1021
  BINNING_INDEX:   1
  IM_URL:          sw01340561000msuni0190.fits
  SUN_POSTN:       137.86d {+09h 11m 26s}  +16.22d {+16d 13' 02"}
  SUN_DIST:        120.12 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.62d {+19h 50m 28s}  -25.33d {-25d 19' 29"}
  MOON_DIST:        62.51 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.30,-57.99 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      336.55,-57.35 [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:     Thu 07 Aug 25 15:52:32 UT
  NOTICE_TYPE:     Swift-UVOT Position
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  GRB_RA:           15.6374d {+01h 02m 32.97s} (J2000),
                    15.9008d {+01h 03m 36.19s} (current),
                    15.1210d {+01h 00m 29.04s} (1950)
  GRB_DEC:         -59.1188d {-59d 07' 07.6"} (J2000),
                   -58.9816d {-58d 58' 53.9"} (current),
                   -59.3872d {-59d 23' 14.0"} (1950)
  GRB_ERROR:       0.8 [arcsec radius, statistical only]
  GRB_MAG:         16.30 +/- 0.14 [mag]
  FILTER:          10, White
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56738.00 SOD {15:45:38.00} UT,   150.1 [sec] since BAT Trigger Time
  SUN_POSTN:       137.86d {+09h 11m 26s}  +16.22d {+16d 13' 01"}
  SUN_DIST:        120.08 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.62d {+19h 50m 30s}  -25.32d {-25d 19' 23"}
  MOON_DIST:        62.54 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.24,-57.95 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      336.54,-57.40 [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 1.1 arcsec from the XRT position.  
  COMMENTS:        Result based on Genie data.  
  COMMENTS:        Notice generated automatically.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Thu 07 Aug 25 15:52:56 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  POINT_RA:         15.579d {+01h 02m 19s} (J2000)
  POINT_DEC:       -59.087d {-59d 05' 13"} (J2000)
  ROLL:            110.080d
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56900.74 SOD {15:48:20.74} UT,   312.8 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     776274536
  X_OFFSET:        1112 [pixels]
  Y_OFFSET:        861 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1272
  Y_GRB_POS:       1021
  BINNING_INDEX:   1
  IM_URL:          sw01340561000msuni0349.fits
  SUN_POSTN:       137.86d {+09h 11m 26s}  +16.22d {+16d 13' 01"}
  SUN_DIST:        120.12 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.63d {+19h 50m 31s}  -25.32d {-25d 19' 20"}
  MOON_DIST:        62.51 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.30,-57.99 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      336.55,-57.36 [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 #41268
  N. J. Klingler (GSFC/UMBC/CRESSTII), R. Brivio (INAF-OAB), J. J. DeLaunay (PSU), S. Dichiara (PSU), R. Gupta (NASA GSFC), S. Lanava (PSU), M. J. Moss (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), C. Salvaggio (INAF-OAB) and M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
  At 15:43:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250807B (trigger=1340561). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 15.585, -59.094 which is

     RA(J2000) = 01h 02m 21s
     Dec(J2000) = -59d 05' 37"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows complex activity during the slew that immediately preceded this trigger, with a total observed duration of about 100 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~15 sec after the trigger.
  The XRT began observing the field at 15:45:32.3 UT, 144.5 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 15.6378, -59.1186 which is equivalent to:

     RA(J2000)  = 01h 02m 33.07s
     Dec(J2000) = -59d 07' 07.0"
  

  with an uncertainty of 5.6 arcseconds (radius, 90% containment). This location is 131 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
  UVOT took a finding chart exposure of 150 seconds with the White filter starting 153 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at

    RA(J2000)  =	01:02:32.98 =  15.63741
    DEC(J2000) = -59:07:07.9  = -59.11887
  

  with a 90%-confidence error radius of about 0.75 arc sec. This position is 1.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 16.31 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.016.
  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:     Thu 07 Aug 25 15:53:07 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     1340561,   Seg_Num: 0
  POINT_RA:         15.579d {+01h 02m 19s} (J2000)
  POINT_DEC:       -59.087d {-59d 05' 13"} (J2000)
  ROLL:            110.080d
  IMG_START_DATE:  20894 TJD;   219 DOY;   25/08/07
  IMG_START_TIME:  56900.74 SOD {15:48:20.74} UT,   312.8 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     776274536
  X_OFFSET:        1112 [pixels]
  Y_OFFSET:        861 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1272
  Y_GRB_POS:       1021
  BINNING_INDEX:   1
  IM_URL:          sw01340561000msuni0349.fits
  SUN_POSTN:       137.86d {+09h 11m 26s}  +16.22d {+16d 13' 01"}
  SUN_DIST:        120.12 [deg]   Sun_angle= 8.1 [hr] (West of Sun)
  MOON_POSTN:      297.63d {+19h 50m 31s}  -25.32d {-25d 19' 18"}
  MOON_DIST:        62.51 [deg]
  MOON_ILLUM:      97 [%]
  GAL_COORDS:      300.30,-57.99 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      336.55,-57.36 [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 Circular #41271
  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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB250807.65 (trigger No 1340561,01h 02m 20.40s , -59d 05m 38.4s, R=0.05) errorbox 10317 sec after notice time and 10401 sec after trigger time at 2025-08-07 18:36:29 UT, with upper limit up to 17.8 mag. The observations began at zenith distance = 76 deg. The sun altitude is -32.1 deg.
  The galactic latitude b = -58 deg., longitude l = 300 deg.
  Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2963168
  We obtain a following upper limits.

  Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
  _________|_____________________|_____|_______|______|________
  
     10491 |         MASTER-SAAO |   C |   180 | 17.1 |        
     10491 |         MASTER-SAAO |   C |   180 | 17.8 |        
  

  Filter C is a clear (unfiltred) band.
  The observation and reduction will continue. The message may be cited.
• GCN Circular #41272
  M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
  Using 1712 s of XRT Photon Counting mode data and 5 UVOT images for GRB 250807B, 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 = 15.63710, -59.11896 which is equivalent to:

  RA (J2000): 01h 02m 32.90s
  Dec (J2000): -59d 07' 08.3"
  

  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 #41278
  J. N. D. van Dalen (Radboud), D. B. Malesani (DAWN/NBI and Radboud), G. Corcoran (UCD), L. Cotter (UCD), M. Fraser (UCD), A. Martin-Carrillo (UCD), L. Galbany (IEEC-CSIC), T. Petrushevska (Nova Gorica), S. Srivastav (Oxford), L. Izzo (INAF/OAC and DARK/NBI), P. D'Avanzo (INAF/OAB), J. Anderson (ESO), T. Müller Bravo (Southampton), T.-W. Chen (NCU), M. Gromadzki (Warsaw), C. Inserra (Cardiff), E. Kankare (Turku), M. Nicholl (QUB), O. Yaron (Weizmann), D. Young (QUB), E. Zimmerman (Weizmann) report on behalf of the ePESSTO+ collaboration:
  We observed the optical counterpart of the Swift GRB 250807B (Klingler et al., GCN 41268) using the ESO NTT located in La Silla (Chile), equipped with the EFOSC2 camera. A total of 600 s imaging was secured in each of the Gunn r and g bands, with mean epoch 2025 Aug 8.15 UT (11.9 hr after the trigger).
  The optical afterglow is well detected in both filters. We measure the following J2000 coordinates (~0.3" error):

  RA = 01:02:33.04
  Dec = -59:07:09.1
  

  The object has a magnitude r = 20.4 +- 0.2 AB (calibrated against nearby stars from the SkyMapper catalog, and not corrected for Galactic extinction), where the error mostly stems from calibrators scatter.
  We acknowledge expert support from the NTT operator, Duncan Castex.
• GCN Circular #41280
  A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA), 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 6.3 ks of XRT data for GRB 250807B, from 133 s to 50.6 ks after the trigger. The data comprise 188 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+3.8 ks) can be modelled with a power-law decay with a decay index of alpha=1.16 (+0.14, -0.13).
  A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.96 (+/-0.07). The best-fitting absorption column is 4.2 (+1.5, -1.4) x 10^20 cm^-2, in excess of the Galactic value of 1.9 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.97 (+0.21, -0.19) and a best-fitting absorption column of 5.8 (+4.7, -4.0) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1.
  A summary of the PC-mode spectrum is thus:

  Total column:	     5.8 (+4.7, -4.0) x 10^20 cm^-2
  Galactic foreground: 1.9 x 10^20 cm^-2
  Excess significance: <1.6 sigma
  Photon index:	     1.97 (+0.21, -0.19)
  

  If the light curve continues to decay with a power-law decay index of 1.16, the count rate at T+24 hours will be 6.4 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.1 x 10^-13 (2.4 x 10^-13) erg cm^-2 s^-1.
  The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01340561.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #41289
  I. F. Giudice (INAF/OACn), M. Garnichey (LUX-Paris Obs.), A. L. Thakur (INAF-IAPS), A. Saccardi (CEA/Irfu), L. Izzo (INAF/OACn & DARK/NBI), A. Martin-Carrillo (UCD), M. De Pasquale (U.Messina), N. R. Tanvir (U. Leicester), S. D. Vergani (LUX-Paris Obs.), D. B. Malesani (DAWN/NBI and Radboud Univ.), report on behalf of the Stargate collaboration:
  We observed the optical counterpart (Kingler et al., GCN 41268; van Dalen et al., GCN 41278) of GRB 250807B detected by Swift with ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph. Our spectra cover the wavelength range 3000-21000 A, and consist of 4 exposures of 600 s each. Observation started on 2025-08-08 at 08:42:42 UTC (17 hours after trigger).
  In a preliminary reduction of the spectra, we identify several absorption features, which we interpret as Fe II, the Mg II doublet, and Mg I, from which we derive a redshift of z = 1.522. We notice the absence of emission or fine-structure lines. The presence of a continuum in the UVB arm supports the interpretation that this could be the GRB redshift.
  The analysis of this spectrum was carried out with the help of the zHunter tool (https://doi.org/10.5281/zenodo.15189495).
  We acknowledge excellent support from the ESO observing staff in Paranal.
• GCN Circular #41293
  M. Freeberg (KNC), D. Turpin (CEA-Saclay/Irfu), C. Andrade(UMN), M. Pillas (ULiege), M. Mašek (Institute of Physics, Prague, FZU, CZ), M. Molham (NRIAG), S. Antier (OCA/IJCLAB) on behalf of the GRANDMA/Kilonova-Catcher collaboration:
  We observed the field of GRB 250807B (Klingler et al., GCN 41268) detected by Swift/BAT with the GRANDMA citizen science project Kilonova-catcher (KNC). Our observations were performed with the iTelescope T72 telescope operated by M. Freeberg. Our observations started at T0+11.9hr.
  In our stacked frames, subtracted from the Legacy Survey DR10 template image, we detect a faint uncatalogued optical source inside the Swift/XRT position (Klingler et al., GCN 41268; Goad et al., GCN 41272) and consistent with the Swift/UVOT (Klingler et al., GCN 41268), NTT (van Dalen et al., GCN 41278) and the VLT/X-shooter (Giudice et al., GCN41289) optical afterglow .
  We report our follow-up results in the table below:

  +---------------+-----------+-----------+----------------+--------------+
  | Tmid-TGRB (hr)| Exp (s)   | Filter    | Magnitude      | Instrument   |
  +===============+===========+===========+================+==============+
  | 12.4          | 11 x 300s | Rc (Vega) | 20.37 +/- 0.25 | iT72         | 
  +---------------+-----------+-----------+----------------+--------------+
  

  All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained with the Johnson-cousins filters were calibrated using the GAIA DR3 synphot catalog.
  We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023).
  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 #41294
  S. P. R. Shilling (Lancaster U.) and N. J. Klingler (GSFC/UMBC/CRESSTII) report on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 250807B 154 s after the BAT trigger (Klingler et al., GCN Circ. 41268). A source consistent with the enhanced XRT position (Goad et al., GCN Circ. 41272) is detected in the initial UVOT exposures.
  Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:

  Filter         T_start(s)   T_stop(s)      Exp(s)           Mag
  
  white              154          303          147         16.30 +/- 0.03
  u_FC               313          339           26         15.05 +/- 0.06
  u		   50186	50647	     450 	 19.86 +/- 0.28
  v_FC	           134		145	      10	 >17.31
  v		   61831	61845	      14	 >17.45
  w1		   38723	39497	     761	 19.64 +/- 0.20
  w2		   60924	61824	     886	 >20.8
  

  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.016 in the direction of the burst (Schlegel et al. 1998).
• GCN Circular #41312
  Y. N. Ma, Z. H. Yao, L. P. Xin, Y. L. Qiu, C. Wu, H. L. Li, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA) report on behalf of the SVOM/VT team.
  SVOM/VT performed a Target of Opportunity observation of GRB 250807B detected by Swift/BAT (Klingler et al., GCN 41268). The observation began at 2025-08-09T19:37:17 UTC, 51.903 hours after the trigger, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
  The optical counterpart (Klingler et al., GCN 41268; Goad et al., GCN 41272; van Dalen et al., GCN 41278; Giudice et al., GCN 41289; Freeberg et al., GCN 41293; Shilling et al,. GCN 41294) was detected in both VT_R and VT_B. The magnitudes are:

  Mid-time (h)   | exposure time (s) | band | mag (AB) | mag err
  ---------------|-------------------|------|----------|--------
      53.83      |      24*70        | VT_B |   23.7   |  0.3 
      53.84      |      24*70        | VT_R |   22.9   |  0.3
  

  Our photometry was not corrected for Galactic extinction.
  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 #41333
  S. D. Barthelmy (GSFC), R. Gupta (GSFC), N. J. Klingler (GSFC/UMBC/CRESSTII), 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), T. Sakamoto (AGU) (i.e. the Swift-BAT team):
  Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 250807B (trigger #1340561) (Klingler, et al., GCN Circ. 41268). The BAT ground-calculated position is RA, Dec = 15.611, -59.098 deg which is

     RA(J2000)  =  01h 02m 26.7s 
     Dec(J2000) = -59d 05' 52.2" 
  

  with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 64%.
  The mask-weighted light curve displays a complex structure with several pulses. The T90 (15-350 keV) is 104.17 +- 29.17 sec (estimated error including systematics).
  The time-averaged spectrum from T-51.00 to T+85.16 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.72 +- 0.12. The fluence in the 15-150 keV band is 2.5 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T-48.59 sec in the 15-150 keV band is 0.9 +- 0.3 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/1340561