Gamma-ray Burst 210210A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:00:39 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  GRB_RA:          262.811d {+17h 31m 15s} (J2000),
                   263.051d {+17h 32m 12s} (current),
                   262.243d {+17h 28m 58s} (1950)
  GRB_DEC:         +14.648d {+14d 38' 53"} (J2000),
                   +14.634d {+14d 38' 01"} (current),
                   +14.684d {+14d 41' 04"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       698 [cnts]    Image_Peak=65 [image_cnts]
  TRIGGER_DUR:     0.128 [sec] 
  TRIGGER_INDEX:   122     E_range: 25-100 keV
  BKG_INTEN:       23672 [cnts]
  BKG_TIME:        7213.51 SOD {02:00:13.51} UT
  BKG_DUR:         8 [sec]
  GRB_DATE:        19255 TJD;    41 DOY;   21/02/10
  GRB_TIME:        7227.91 SOD {02:00:27.91} UT
  GRB_PHI:         154.01 [deg]
  GRB_THETA:        35.45 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     16.24 [sigma]
  IMAGE_SIGNIF:    7.51 [sigma]
  MERIT_PARAMS:     +1  +0  +0  -3  +2  -2  +0  +0 -38  +0 
  SUN_POSTN:       323.93d {+21h 35m 43s}  -14.32d {-14d 19' 05"}
  SUN_DIST:         66.81 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.40d {+20h 13m 36s}  -23.48d {-23d 28' 57"}
  MOON_DIST:        54.85 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.24 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      261.18, 37.87 [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 = 54.99,18.77 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:01:56 UT
  NOTICE_TYPE:     Swift-XRT Nack-Position
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.815d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.652d {+14d 39' 08"} (J2000)
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7310.00 SOD {02:01:50.00} UT,   82.1 [sec] since BAT Trigger Time
  COUNTS:          2    Min_needed= 20
  STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
  PH2_ITER:        1    Max_iter_allowed= 4
  ERROR_CODE:      1
  COMMENTS:        SWIFT-XRT Nack Position.  
  COMMENTS:        No source found in the image.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:19:07 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  GRB_RA:          262.811d {+17h 31m 15s} (J2000),
                   263.051d {+17h 32m 12s} (current),
                   262.243d {+17h 28m 58s} (1950)
  GRB_DEC:         +14.648d {+14d 38' 53"} (J2000),
                   +14.634d {+14d 38' 01"} (current),
                   +14.684d {+14d 41' 04"} (1950)
  GRB_DATE:        19255 TJD;    41 DOY;   21/02/10
  GRB_TIME:        7227.91 SOD {02:00:27.91} UT
  TRIGGER_INDEX:   122
  GRB_PHI:         154.01 [deg]
  GRB_THETA:        35.45 [deg]
  DELTA_TIME:      2270.00 [sec]
  TRIGGER_DUR:     0.128 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     16.24 [sigma]
  IMAGE_SIGNIF:    7.51 [sigma]
  LC_URL:          sw01031728000msb.lc
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 50"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.59d {+20h 14m 21s}  -23.46d {-23d 27' 19"}
  MOON_DIST:        54.97 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.24 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      261.18, 37.87 [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 = 54.99,18.77 [deg].  
  COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:19:50 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.815d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.652d {+14d 39' 08"} (J2000)
  POINT_ROLL:      112.870d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7313.02 SOD {02:01:53.02} UT,   85.1 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        2.649
  N_STARS:         134
  X_OFFSET:        461 [pixels]
  Y_OFFSET:        591 [pixels]
  X_MAX:           1420 [pixels]
  Y_MAX:           1550 [pixels]
  DET_THRESH:      13
  PHOTO_THRESH:    7
  SL_URL:          sw01031728000msufc0085.fits
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 50"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.59d {+20h 14m 22s}  -23.45d {-23d 27' 15"}
  MOON_DIST:        54.97 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:20:09 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.815d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.652d {+14d 39' 08"} (J2000)
  ROLL:            112.870d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7313.02 SOD {02:01:53.02} UT,   85.1 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     634615339
  X_OFFSET:        780 [pixels]
  Y_OFFSET:        910 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       940
  Y_GRB_POS:       1070
  BINNING_INDEX:   1
  IM_URL:          sw01031728000msuni0112.fits
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 50"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.60d {+20h 14m 23s}  -23.45d {-23d 27' 14"}
  MOON_DIST:        54.97 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [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:     Wed 10 Feb 21 02:20:21 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.815d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.652d {+14d 39' 08"} (J2000)
  ROLL:            112.870d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7313.02 SOD {02:01:53.02} UT,   85.1 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     634615339
  X_OFFSET:        780 [pixels]
  Y_OFFSET:        910 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       940
  Y_GRB_POS:       1070
  BINNING_INDEX:   1
  IM_URL:          sw01031728000msuni0112.fits
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 49"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.60d {+20h 14m 24s}  -23.45d {-23d 27' 13"}
  MOON_DIST:        54.98 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Image.  
  COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
  COMMENTS:        The image has 2x2 binning (compression).  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:20:11 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.815d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.652d {+14d 39' 08"} (J2000)
  POINT_ROLL:      112.870d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7313.02 SOD {02:01:53.02} UT,   85.1 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        2.649
  N_STARS:         134
  X_OFFSET:        461 [pixels]
  Y_OFFSET:        591 [pixels]
  X_MAX:           1420 [pixels]
  Y_MAX:           1550 [pixels]
  DET_THRESH:      13
  PHOTO_THRESH:    7
  SL_URL:          sw01031728000msufc0085.fits
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 50"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.60d {+20h 14m 23s}  -23.45d {-23d 27' 13"}
  MOON_DIST:        54.97 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [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:     Wed 10 Feb 21 02:21:43 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.816d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.649d {+14d 38' 58"} (J2000)
  POINT_ROLL:      112.869d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7525.56 SOD {02:05:25.56} UT,   297.7 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        0.795
  N_STARS:         165
  X_OFFSET:        221 [pixels]
  Y_OFFSET:        351 [pixels]
  X_MAX:           1660 [pixels]
  Y_MAX:           1790 [pixels]
  DET_THRESH:      8
  PHOTO_THRESH:    3
  SL_URL:          sw01031728000msufc0297.fits
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 48"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.61d {+20h 14m 27s}  -23.45d {-23d 27' 05"}
  MOON_DIST:        54.98 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:22:08 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.816d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.649d {+14d 38' 58"} (J2000)
  ROLL:            112.869d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7525.56 SOD {02:05:25.56} UT,   297.7 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     634615552
  X_OFFSET:        780 [pixels]
  Y_OFFSET:        910 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       940
  Y_GRB_POS:       1070
  BINNING_INDEX:   1
  IM_URL:          sw01031728000msuni0324.fits
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 48"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.62d {+20h 14m 28s}  -23.45d {-23d 27' 03"}
  MOON_DIST:        54.98 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [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:     Wed 10 Feb 21 02:22:26 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.816d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.649d {+14d 38' 58"} (J2000)
  ROLL:            112.869d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7525.56 SOD {02:05:25.56} UT,   297.7 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     634615552
  X_OFFSET:        780 [pixels]
  Y_OFFSET:        910 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       940
  Y_GRB_POS:       1070
  BINNING_INDEX:   1
  IM_URL:          sw01031728000msuni0324.fits
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 48"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.62d {+20h 14m 29s}  -23.45d {-23d 27' 01"}
  MOON_DIST:        54.99 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Image.  
  COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
  COMMENTS:        The image has 2x2 binning (compression).  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:22:03 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.816d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.649d {+14d 38' 58"} (J2000)
  POINT_ROLL:      112.869d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7525.56 SOD {02:05:25.56} UT,   297.7 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        0.795
  N_STARS:         165
  X_OFFSET:        221 [pixels]
  Y_OFFSET:        351 [pixels]
  X_MAX:           1660 [pixels]
  Y_MAX:           1790 [pixels]
  DET_THRESH:      8
  PHOTO_THRESH:    3
  SL_URL:          sw01031728000msufc0297.fits
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 48"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.62d {+20h 14m 28s}  -23.45d {-23d 27' 03"}
  MOON_DIST:        54.98 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [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:     Wed 10 Feb 21 02:23:33 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.816d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.650d {+14d 38' 59"} (J2000)
  POINT_ROLL:      112.869d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  8105.69 SOD {02:15:05.69} UT,   877.8 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        2.813
  N_STARS:         190
  X_OFFSET:        221 [pixels]
  Y_OFFSET:        351 [pixels]
  X_MAX:           1660 [pixels]
  Y_MAX:           1790 [pixels]
  DET_THRESH:      14
  PHOTO_THRESH:    7
  SL_URL:          sw01031728000msufc0877.fits
  SUN_POSTN:       323.94d {+21h 35m 47s}  -14.31d {-14d 18' 47"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.63d {+20h 14m 31s}  -23.45d {-23d 26' 55"}
  MOON_DIST:        54.99 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:23:42 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.816d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.650d {+14d 38' 59"} (J2000)
  ROLL:            112.869d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  8105.69 SOD {02:15:05.69} UT,   877.8 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     634616132
  X_OFFSET:        780 [pixels]
  Y_OFFSET:        910 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       940
  Y_GRB_POS:       1070
  BINNING_INDEX:   1
  IM_URL:          sw01031728000msuni0904.fits
  SUN_POSTN:       323.94d {+21h 35m 47s}  -14.31d {-14d 18' 47"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.63d {+20h 14m 32s}  -23.45d {-23d 26' 55"}
  MOON_DIST:        54.99 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [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:     Wed 10 Feb 21 02:23:52 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.816d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.650d {+14d 38' 59"} (J2000)
  ROLL:            112.869d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  8105.69 SOD {02:15:05.69} UT,   877.8 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     634616132
  X_OFFSET:        780 [pixels]
  Y_OFFSET:        910 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       940
  Y_GRB_POS:       1070
  BINNING_INDEX:   1
  IM_URL:          sw01031728000msuni0904.fits
  SUN_POSTN:       323.94d {+21h 35m 47s}  -14.31d {-14d 18' 47"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.63d {+20h 14m 32s}  -23.45d {-23d 26' 54"}
  MOON_DIST:        54.99 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Image.  
  COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
  COMMENTS:        The image has 2x2 binning (compression).  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:22:56 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  GRB_RA:          262.7705d {+17h 31m 04.92s} (J2000),
                   263.0105d {+17h 32m 02.51s} (current),
                   262.2023d {+17h 28m 48.55s} (1950)
  GRB_DEC:         +14.6639d {+14d 39' 50.0"} (J2000),
                   +14.6494d {+14d 38' 57.6"} (current),
                   +14.7003d {+14d 42' 01.0"} (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:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7373.00 SOD {02:02:53.00} UT,   145.1 [sec] since BAT Trigger Time
  TAM[0-3]:        100.00 100.00 100.00 100.00
  AMPLIFIER:       1
  WAVEFORM:        31
  SUN_POSTN:       323.94d {+21h 35m 46s}  -14.31d {-14d 18' 47"}
  SUN_DIST:         66.86 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.62d {+20h 14m 30s}  -23.45d {-23d 26' 59"}
  MOON_DIST:        55.03 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.57, 24.28 [deg] galactic lon,lat of the burst
  ECL_COORDS:      261.13, 37.88 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Coordinates.  
  COMMENTS:        This Notice was ground-generated -- not flight-generated.  
  COMMENTS:        TAM values, flux and significance fields are not valid.  
  COMMENTS:        This position was automatically generated on the ground using  
  COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
  COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
  COMMENTS:        The probability that this is a serendipitous source in the  
  COMMENTS:        SPER window is 1.1% < P(seren) < 2.8%.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:23:55 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  POINT_RA:        262.816d {+17h 31m 16s} (J2000)
  POINT_DEC:       +14.650d {+14d 38' 59"} (J2000)
  POINT_ROLL:      112.869d
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  8105.69 SOD {02:15:05.69} UT,   877.8 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        2.813
  N_STARS:         190
  X_OFFSET:        221 [pixels]
  Y_OFFSET:        351 [pixels]
  X_MAX:           1660 [pixels]
  Y_MAX:           1790 [pixels]
  DET_THRESH:      14
  PHOTO_THRESH:    7
  SL_URL:          sw01031728000msufc0877.fits
  SUN_POSTN:       323.94d {+21h 35m 47s}  -14.31d {-14d 18' 47"}
  SUN_DIST:         66.82 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.63d {+20h 14m 32s}  -23.45d {-23d 26' 53"}
  MOON_DIST:        54.99 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.58, 24.23 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      261.18, 37.87 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN Circular #29444
  S. Laha (GSFC/UMBC/CRESST), J.D. Gropp (PSU), H. A. Krimm (NSF), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (PSU) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team:
  At 02:00:27 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210210A (trigger=1031728). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 262.811, +14.648 which is

     RA(J2000) = 17h 31m 15s
     Dec(J2000) = +14d 38' 53"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Due to a telemetry gap, only the first 8 seconds of the BAT light curve after the trigger are available, showing that the emission has at least two peaks and continues beyond that time. The peak count rate was ~6000 counts/sec (15-350 keV), at ~4 sec after the trigger.
  The XRT began observing the field at 02:01:50.0 UT, 82.1 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 262.77059, 14.66385 which is equivalent to:

     RA(J2000)  = 17h 31m 04.94s
     Dec(J2000) = +14d 39' 49.9"
  

  with an uncertainty of 3.5 arcseconds (radius, 90% containment). This location is 151 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 (8.82 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.2 (+1.27/-1.18) x 10^21 cm^-2 (90% confidence).
  UVOT took a finding chart exposure of 150 seconds with the White filter starting 85 seconds after the BAT trigger. There is a candidate afterglow in the list of sources generated on-board at

    RA(J2000)  =	17:31:05.00 = 262.77085
    DEC(J2000) = +14:39:45.8  =  14.66272
  

  with a 90%-confidence error radius of about 1.10 arc sec. This position is 4.6 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.06. No correction has been made for the expected extinction corresponding to E(B-V) of 0.097.
  Burst Advocate for this burst is S. Laha (sib.laha 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 Circular #29445
  V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department),
  R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
  R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
  D. Buckley (South African Astronomical Observatory),
  O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API),
  A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
  V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University)
  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 GRB 210210A ( S. Laha et al., GCN 29444) errorbox 1609 sec after notice time and 1649 sec after trigger time at 2021-02-10 02:27:57 UT, with upper limit up to 16.5 mag. The observations began at zenith distance = 78 deg. The sun altitude is -20.7 deg.
  The galactic latitude b = 24 deg., longitude l = 38 deg.
  Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1544104
  We obtain a following upper limits.

  Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
  _________|_____________________|_____|_______|______|________
  
      1739 |         MASTER-SAAO | P\  |   180 | 15.1 |        
      1939 |         MASTER-SAAO | P\  |   180 | 16.5 |        
  

  The observation and reduction will continue. The message may be cited.
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Wed 10 Feb 21 02:25:19 UT
  NOTICE_TYPE:     Swift-UVOT Position
  TRIGGER_NUM:     1031728,   Seg_Num: 0
  GRB_RA:          262.7708d {+17h 31m 04.99s} (J2000),
                   263.0108d {+17h 32m 02.59s} (current),
                   262.2026d {+17h 28m 48.62s} (1950)
  GRB_DEC:         +14.6627d {+14d 39' 45.7"} (J2000),
                   +14.6482d {+14d 38' 53.3"} (current),
                   +14.6991d {+14d 41' 56.7"} (1950)
  GRB_ERROR:       1.1 [arcsec radius, statistical only]
  GRB_MAG:         17.05 +/- 0.40 [mag]
  FILTER:          10, White
  IMG_START_DATE:  19255 TJD;    41 DOY;   21/02/10
  IMG_START_TIME:  7310.00 SOD {02:01:50.00} UT,   82.1 [sec] since BAT Trigger Time
  SUN_POSTN:       323.95d {+21h 35m 47s}  -14.31d {-14d 18' 45"}
  SUN_DIST:         66.86 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
  MOON_POSTN:      303.65d {+20h 14m 36s}  -23.45d {-23d 26' 46"}
  MOON_DIST:        55.04 [deg]
  MOON_ILLUM:      3 [%]
  GAL_COORDS:       37.57, 24.28 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      261.13, 37.88 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT UVOT Position Notice.  
  COMMENTS:        This Notice was ground-generated -- not flight-generated.  
  COMMENTS:        Result based on srclist data.  
  COMMENTS:        Notice generated automatically.  
  

• GCN Circular #29447
  V. Lipunov, V.Kornilov, E.Gorbovskoy,N.Tiurina,P.Balanutsa,F.Balakin, V.Vladimirov, A.Kuznetsov,K.Zhirkov,D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, A.Chasovnikov,A.Pozdnyakov,V.Topolev, D.Cheryasov(Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico FelixAguilar OAFA), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
  MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru Lipunov et al.,2010,Advances in Astronomy,2010,30L) automatically was pointed to Swift GRB 200210A (Laha et al. GCN 29444,Ttrigger 02:00:27UT) at 2021-02-10 02:03:54UT (first exposition), but the alert altitude was 07 degrees (under the roof, so there is no stars at first images) and roses above the roof only 27min after trigger time (Lipunov et al. GCN 29445).
  MASTER auto-detection system found optical afterglow MASTER OT J173104.99+143945.9 (discovered by Swift-UVOT, GCN 29444). We observed it untill sunrise (MASTER automatical programm of Swift alert observations).
  The reduction of MASTER wide field and very wide field cameras images will be continued. This message may be cited.
• GCN Circular #29448
  M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
  Using 1221 s of XRT Photon Counting mode data and 2 UVOT images for GRB 210210A, 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 = 262.77041, +14.66257 which is equivalent to:

  RA (J2000): 17h 31m 4.90s
  Dec (J2000): +14d 39' 45.2"
  

  with an uncertainty of 1.7 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 #29450
  A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), and D. Garcia (GRANTECAN) report:
  We observed the afterglow of GRB 210210A (Laha et al., GCN #29444, Lipunov et al., GCN #29447) with OSIRIS at the 10.4m Gran Telescopio Canarias (Roque de los Muchachos Observatory, La Palma, Canary Islands, Spain), starting at 2021-02-10 06:18:28.465 UT (4.300 hours after the trigger). The source is clearly detected. We obtained 3 x 900 s spectroscopy with the R1000B grism, covering the spectral range from 3700 to 7800 AA.
  From the 30 s image starting at 2021-02-10 06:14:20.350 (0.1763 days after the trigger), we measure r' = 18.84 +/- 0.03 mag (AB) vs. a nearby PanSTARRS star. We note this indicates a slow decay compared with the initial Swift detection (Laha et al., GCN #29444). Further photometric follow-up is encouraged.
  The spectrum shows a strong continuum over the full spectral range with several absorption lines. We identify these as FeII, MgII, and MgI, at a mean redshift of z = 0.715. At this redshift, we also detect OII in emission, which allows us to identify this as the redshift of the GRB. We also find an intervening system in MgII and MgI at z = 0.481.
• GCN Circular #29452
  V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), J. D. Gropp (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB) and S. Laha report on behalf of the Swift-XRT team:
  We have analysed 7.7 ks of XRT data for GRB 210210A (Laha et al. GCN Circ. 29444), from 85 s to 35.6 ks after the BAT trigger. The data comprise 58 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 29448).
  The light curve can be modelled with an initial power-law decay with an index of alpha=0.27 (+/-0.07), followed by a break at T+1018 s to an alpha of 1.06 (+0.45, -0.04).
  A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.85 (+/-0.12). The best-fitting absorption column is 1.3 (+0.4, -0.3) x 10^21 cm^-2, in excess of the Galactic value of 8.8 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1.
  A summary of the PC-mode spectrum is thus:

  Total column:	     1.3 (+0.4, -0.3) x 10^21 cm^-2
  Galactic foreground: 8.8 x 10^20 cm^-2
  Excess significance: 2.1 sigma
  Photon index:	     1.85 (+/-0.12)
  

  If the light curve continues to decay with a power-law decay index of 1.06, the count rate at T+24 hours will be 0.021 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.9 x 10^-13 (9.7 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/01031728.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #29457
  A. A. Breeveld (UCL-MSSL) and S. L. Laha (GSFC/UMBC/CRESST) report on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 210210A 85 s after the BAT trigger (Laha et al., GCN Circ. 29444). A fading source consistent with the XRT position (Goad et al. GCN Circ. 29448) is detected in the initial UVOT exposures, as also detected by Lipunov et al. (GCN Circ. 29447) and de Ugarte Postigo et al. (GCN Circ. 29450).
  The preliminary UVOT position is:

       RA  (J2000) =  17:31:05.01 = 262.77088 (deg.)
       Dec (J2000) = +14:39:46.4  =  14.66290 (deg.)
  

  with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
  Preliminary detections 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            85          235          147         16.04 ± 0.03
  white              878         1028          147         16.57 ± 0.06
  v                  629          648           20         16.95 ± 0.19
  b                  553          573           20         16.99 ± 0.11
  u                  298          547          246         15.91 ± 0.03
  w1                 679          699           19         16.05 ± 0.15
  m2                 827          847           19         16.13 ± 0.20
  w2                 779          798           20         16.35 ± 0.18
  

  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.097 in the direction of the burst (Schlegel et al. 1998).
• GCN Circular #29459
  R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration:
  We observed Swift GRB 210210A (Laha, GCN 29444) with the LCO 1-m Sinistro instrument at the McDonald Observatory, Texas, USA site, on February 10, from 11:31 to 12:02 UT (corresponding to 9.52 to 10.04 hours from the GRB trigger time) with the Bessel R and I filters.
  We performed a series of 5x180s exposures in R and I. We clearly detect an optical source in R and I band in stacked images at a location consistent the initial UVOT detection (Laha, GCN 29444). Using the USNO-B.1 catalog as reference, we calculate the following magnitudes:
  R = 19.62 +/- 0.05
  I = 19.10 +/- 0.06
  These magnitudes are not corrected for galactic extinction.
  R.S. is funded by NSF AST grant #1831682
• GCN Circular #29467
  A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
  Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210210A (trigger #1031728) (Laha, et al., GCN Circ. 29444). The BAT ground-calculated position is RA, Dec = 262.764, 14.657 deg which is

    RA(J2000)  =  17h 31m 03.4s 
    Dec(J2000) = +14d 39' 26.8" 
  

  with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 43%.
  The mask-weighted light curve shows a double-peaked structure running approximately from T-1 sec to T+7 sec. The first pulse peaks close to T+0 sec and the second pulse peaks at T+4.5 sec. T90 (15-350 keV) is 6.60 +- 0.59 sec (estimated error including systematics).
  The time-averaged spectrum from T-0.75 to T+6.93 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.53 +- 0.58, and Epeak of 19.9 +- 13.9 keV (chi squared 44.33 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 9.8 +- 0.8 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+4.21 sec in the 15-150 keV band is 7.0 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.46 +- 0.12 (chi squared 53.94 for 57 d.o.f.). All the quoted errors are at the 90% confidence level.
  The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1031728/BA/
• GCN Circular #29469
  Martin Jelinek and Jan Strobl (ASU CAS Ondrejov, CZ), Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek, Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza (Institute of Physics, Prague, CZ)
  report:
  The 25cm robotic telescope FRAM-ORM at La Palma (Spain) reacted robotically to the alert of GRB210210A (Palmer et al GCNC 29444, Goad et al. GCNC 29448, D'Elia et al. GCNC 29452, and Lien et al GCNC 29467), obtaining a set of 30 x 60 s R-band images starting at 03:37:09.2 UT, i.e. ~97min post trigger.
  We clearly detect the source reported by other telescopes (Lipunov et al. GCN 29447, Fernandez-Garcia et al. GCNC 28763, de Ugarte Postigo et al GCNC 29450, Breeveld & Laha GCNC 29457, and Strausbaugh & Cucchiara GCNC 29459). At the sum of all available images (Tmid=T0+113.2min) we measure the optical afterglow with the brightness R=17.6+-0.2 (Vega) as calibrated against the Atlas catalogue and Lupton transformations.
• GCN Circular #29476
  D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), P. Mínguez, and S. Pedraz (both CAHA) report:
  We observed the afterglow (Laha et al., GCN #29444, Lipunov et al., GCN #29447, de Ugarte Postigo et al., GCN #29450, Breeveld & Laha, GCN #29457, Strausbaugh & Cucchiara, GCN #29459, Jelinek et al., GCN #29469) of the very soft GRB 210210A (Laha et al., GCN #29444) with CAFOS mounted on the 2.2m Calar Alto telescope (Almeria, Spain). We obtained one 180 s image each in BVRc and 3 x 90 s images in Ic. We detect the optical afterglow faintly in BVRc.
  Using the same comparison star used by de Ugarte Postigo et al., and transforming to Rc following the equations of Lupton (2005), then transforming back to AB magnitudes, we derive:
  Rc = 21.89 +/- 0.21 mag at 1.167362 days after the trigger.
  Using the R-band magnitudes from the GCNs listed above (FRAM, Jelinek et al.; GTC, de Ugarte Postigo et al.; LCO, Strausbaugh & Cucchiara), we find an unbroken decay with alpha_1 = 1.05 until 0.41 days post-trigger. However, our detection lies 0.9 magnitudes below the extrapolation. Fixing the break time to 0.41 days, we find a lower limit on the post-break decay alpha_2 > 1.93. We note the X-ray afterglow also shows a potential jet break, with alpha_2 > 3, however, more observations are needed.
• GCN Circular #29481
  R. Ruffini, R. Moradi, Y. Aimuratov, C. L. Bianco, M. Karlica, J.A. Rueda, N. Sahakyan, Y. Wang, Liang Li, S. S. Xue on behalf of the ICRANet team, report:
  GRB 210210A has T90=6.6s , observed by Swif-BAT (GCN 29467), with z=0.715 (GCN 29450), with an isotropic energy of E_iso ~ 2 x 10^51 erg, is the twin of GRB 180728A ( Wang et al 2019 ApJ 874 39) with an isotropic energy of E_iso ~ 3 x 10^51 erg. It presents the typical characteristic of a subclass of long GRBs called Binary-driven Hypernovae of type II (BdHN II) originating from a tight binary of a FeCO Core undergoing a supernova explosion in presence of a companion neutron star (NS) which undergoes hypercritical accretion. The outcome (see Fig. [1]) is a new binary composed by a more massive NS (MNS) and a newly born NS (*v*NS).
  In both GRB 210210A and 180728A The GeV emission is not observed (GCN 29473); as it is expected in BdHN II. The follow-up observation in the X-ray afterglow emission is recommended in order to determine the spin and magnetic field of the new Neutron star (vNS) in this BdHN. We look forward to possible data obtained from Fermi-GBM to recognize the supernovae rise (SN-rise)(see Fig. [2]).
  Using the averaged observed value (Cano et al., 2016), and considering the redshift z=0.715 (A. Rossi et al., GCN 23055), a bright optical signal will peak at 22 +/- 5 days after the trigger. However, the high redshift z=0.715 makes the observation challenging for this source.
  Fig. 1: http://www.icranet.org/documents/SPHsimulation_CO-starSN-NS.pdf Fig. 2: http://www.icranet.org/documents/X-ray_afterglow_GRB180728A-GRB210210A.pdf
• GCN Circular #29488
  Dimple (ARIES), A. Ghosh (ARIES), R. Gupta (ARIES), A. Kumar (ARIES), A. Panchal (ARIES), K. Misra (ARIES), S.B. Pandey (ARIES), Y. C. Joshi (ARIES) report:
  We observed the afterglow (Laha et al. GCN #29444, Lipunov et al. GCN #29447, de Ugarte Postigo et al. GCN #29450, Breeveld & Laha, GCN #29457, Strausbaugh & Cucchiara, GCN #29459, Jelinek et al. GCN #29469, D. A. Kann et al. GCN #29476) of the GRB 210210A (Laha et al. GCN #29444) with 1.3m Devasthal Fast Optical Telescope (DFOT) at Devasthal observatory of Aryabhatta Research Institute of observational sciencES (ARIES), India. We obtained multiple images in R and I bands with an exposure of 180 seconds each. We detect the optical afterglow with a magnitude of 21.35 +- 0.07 in R-band at 0.88 days after the burst. Further observations are ongoing with 1.3m DFOT and 3.6m DOT.
  The magnitude is not corrected for the Galactic extinction in the direction of the burst. The photometric calibration is performed using the standard stars from the USNO-B1.0 catalog.
• GCN Circular #29502
  D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), P. Minguez, and S. Pedraz (both CAHA) report:
  We again observed the afterglow (Laha et al., GCN #29444, Lipunov et al., GCN #29447, de Ugarte Postigo et al., GCN #29450, Breeveld & Laha, GCN #29457, Strausbaugh & Cucchiara, GCN #29459, Jelinek et al., GCN #29469, Kann et al., GCN #29476, Dimple et al., GCN #2948 of GRB 210210A (Laha et al., GCN #29444) with CAFOS mounted on the 2.2m Calar Alto telescope (Almeria, Spain). We obtained 6 x 600 s image in Rc. We detect the optical afterglow faintly in the stacked Rc image.
  Using the same comparison star used by de Ugarte Postigo et al., and transforming to Rc following the equations of Lupton (2005), then transforming back to AB magnitudes, we derive a preliminary magnitude:
  Rc = 23.05 +/- 0.14 mag at 3.129261 days after the trigger.
  Using the R-band magnitudes from the GCNs listed above, now also including Dimple et al., GCN #29488, we confirm the steeper decay found by Kann et al., GCN #29476, finding, with a host-galaxy magnitude as a free parameter:

  alpha_1 = 1.06 +/- 0.18,
  alpha_1 = 2.50 +/- 0.90,
  t_b = 0.45 +/- 0.23 days,
  m_h = 23.19 +/- 0.27 mag (AB).
  

  This fit can be improved with a dedicated host-galaxy observation. We note that the X-ray light curve also shows evidence for a possible jet break at 0.35 +0.27 -0.13 days, in agreement with our result.
• GCN Circular #29517
  D. Frederiks, S. Golenetskii, A.Lysenko, D. Svinkin, A. Ridnaya, A. Tsvetkova, M. Ulanov, T. Cline, on behalf of the Konus-Wind team, and A. Lien (GSFC/UMBC), report:
  The long GRB 210210A (Swift-BAT trigger #1031728, T0 = T0(BAT)= 02:00:27.920 UT: Laha et al., GCN 29444; Lien et al., GCN 29467) was detected by Konus-Wind (KW) in the waiting mode.
  A Bayesian block analysis of the KW waiting mode data in the 20-400 keV band reveals a ~11 sigma count rate increase over background in the interval from ~T0(BAT)-1.7 s to ~T0(BAT)+7.1 s. The KW light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB210210A/
  To derive the broad-band spectral parameters of this burst, we performed a joint spectral analysis of the Swift/BAT data (15-150 keV) and the Konus-Wind 3-channel spectral data, which cover the energy range from ~20 keV to ~1.5 MeV.
  The time-averaged spectrum, measured from T0(BAT)-1.685 s to T0(BAT)+7.147 s, is best fit in the 15 keV - 1.5 MeV range by a power law with an exponential cutoff. This fit gives a photon index alpha -1.68 (-0.23,+0.25), and Ep of 16.6 (-10.7,+7.2) keV (chi^2 = 47.5/ 58 dof). A fit to a simple power law gives a photon index of (2.52 ± 0.07), chi^2 = 58.4/ 59 dof. The joint fit results are consistent with the Swift-BAT refined analysis (GCN 29467).
  In the 15-1500 keV band, the total burst fluence, estimated from the CPL model, is (1.2 ± 0.1)x10^-6 erg/cm^2, and the 2.944 s peak energy flux is (2.4 ± 0.2)x10^-7 erg/cm^2.
  Assuming the redshift z=0.715 (de Ugarte Postigo et al., GCN 29450) and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the isotropic energy release E_iso to ~1.7x10^51 erg, the isotropic luminosity L_iso to ~5.9x10^50 erg/s, and the rest-frame peak energy of the time-integrated spectrum Ep,z to ~29 keV. With these values, GRB 210210A is within 90% prediction bands for both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs with known redshifts (part II: Tsvetkova et al., ApJ, in press), see http://www.ioffe.ru/LEA/GRBs/GRB210210A/GRB210210A_rest_frame.pdf
  All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.