Gamma-ray Burst 070621

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:17:57 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     282808,   Seg_Num: 0
GRB_RA:          323.804d {+21h 35m 13s} (J2000),
                 323.911d {+21h 35m 39s} (current),
                 323.087d {+21h 32m 21s} (1950)
GRB_DEC:         -24.806d {-24d 48' 20"} (J2000),
                 -24.772d {-24d 46' 19"} (current),
                 -25.029d {-25d 01' 45"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5224 [cnts]    Image_Peak=195 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   149     E_range: 25-100 keV
BKG_INTEN:       32238 [cnts]
BKG_TIME:        83845.96 SOD {23:17:25.96} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14272 TJD;   172 DOY;   07/06/21
GRB_TIME:        83859.85 SOD {23:17:39.85} UT
GRB_PHI:          15.57 [deg]
GRB_THETA:        43.09 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     17.29 [sigma]
IMAGE_SIGNIF:    9.01 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +5  +0  +0 +66  +1 
SUN_POSTN:        90.22d {+06h 00m 53s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.30 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      173.91d {+11h 35m 39s}   +1.28d {+01d 16' 56"}
MOON_DIST:       142.70 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.46,-46.12 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      318.04, -9.89 [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 = 72.90,-1.42 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:19:58 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     282808,   Seg_Num: 0
GRB_RA:          323.7909d {+21h 35m 09.8s} (J2000),
                 323.8980d {+21h 35m 35.5s} (current),
                 323.0733d {+21h 32m 17.5s} (1950)
GRB_DEC:         -24.8181d {-24d 49' 05.1"} (J2000),
                 -24.7845d {-24d 47' 04.2"} (current),
                 -25.0417d {-25d 02' 30.1"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       124 [cnts]
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  83970.60 SOD {23:19:30.60} UT,   110.8 [sec] since BAT Trigger Time
CENTROID_X:      260.85,  raw= 261  [pixels]
CENTROID_Y:      349.62,  raw= 350  [pixels]
ROLL:            79.84 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   121.69
GRB_POS_XRT_Z:   -97.69
IMAGE_URL:       sw00282808000msxps_rw.img
SUN_POSTN:        90.22d {+06h 00m 53s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.31 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      173.93d {+11h 35m 42s}   +1.27d {+01d 16' 27"}
MOON_DIST:       142.67 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.44,-46.11 [deg] galactic lon,lat of the burst
ECL_COORDS:      318.02, -9.89 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:20:04 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     282808,   Seg_Num: 0
GRB_RA:          323.7909d {+21h 35m 09.8s} (J2000),
                 323.8980d {+21h 35m 35.5s} (current),
                 323.0733d {+21h 32m 17.5s} (1950)
GRB_DEC:         -24.8181d {-24d 49' 05.1"} (J2000),
                 -24.7845d {-24d 47' 04.2"} (current),
                 -25.0417d {-25d 02' 30.1"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       124 [cnts]
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  83970.60 SOD {23:19:30.60} UT,   110.8 [sec] since BAT Trigger Time
CENTROID_X:      260.85,  raw= 261  [pixels]
CENTROID_Y:      349.62,  raw= 350  [pixels]
ROLL:            79.84 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   121.69
GRB_POS_XRT_Z:   -97.69
IMAGE_URL:       sw00282808000msxps_rw.img
SUN_POSTN:        90.22d {+06h 00m 53s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.31 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      173.93d {+11h 35m 43s}   +1.27d {+01d 16' 26"}
MOON_DIST:       142.67 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.44,-46.11 [deg] galactic lon,lat of the burst
ECL_COORDS:      318.02, -9.89 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:19:57 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     282808,   Seg_Num: 0
GRB_RA:          323.7909d {+21h 35m 09.8s} (J2000),
                 323.8980d {+21h 35m 35.5s} (current),
                 323.0733d {+21h 32m 17.5s} (1950)
GRB_DEC:         -24.8181d {-24d 49' 05.1"} (J2000),
                 -24.7845d {-24d 47' 04.2"} (current),
                 -25.0417d {-25d 02' 30.1"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       3.75e-09 [erg/cm2/sec]
GRB_SIGNIF:      11.13 [sigma]
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  83970.60 SOD {23:19:30.60} UT,   110.8 [sec] since BAT Trigger Time
TAM[0-3]:        327.62 237.18 261.14 243.51
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        90.22d {+06h 00m 53s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.31 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      173.93d {+11h 35m 42s}   +1.27d {+01d 16' 27"}
MOON_DIST:       142.67 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.44,-46.11 [deg] galactic lon,lat of the burst
ECL_COORDS:      318.02, -9.89 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact; see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:21:04 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     282808,   Seg_Num: 0
GRB_RA:          323.804d {+21h 35m 13s} (J2000),
                 323.911d {+21h 35m 39s} (current),
                 323.087d {+21h 32m 21s} (1950)
GRB_DEC:         -24.806d {-24d 48' 20"} (J2000),
                 -24.772d {-24d 46' 19"} (current),
                 -25.029d {-25d 01' 45"} (1950)
GRB_DATE:        14272 TJD;   172 DOY;   07/06/21
GRB_TIME:        83859.85 SOD {23:17:39.85} UT
TRIGGER_INDEX:   149
GRB_PHI:          15.57 [deg]
GRB_THETA:        43.09 [deg]
DELTA_TIME:      52.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     17.29 [sigma]
IMAGE_SIGNIF:    9.01 [sigma]
LC_URL:          sw00282808000msb.lc
SUN_POSTN:        90.22d {+06h 00m 53s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.30 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      173.93d {+11h 35m 44s}   +1.27d {+01d 16' 11"}
MOON_DIST:       142.68 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.46,-46.12 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      318.04, -9.89 [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 = 72.90,-1.42 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:21:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.769d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 21"} (J2000)
POINT_ROLL:      79.838d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  83980.03 SOD {23:19:40.03} UT,   120.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.825
N_STARS:         44
X_OFFSET:        592 [pixels]
Y_OFFSET:        136 [pixels]
X_MAX:           1551 [pixels]
Y_MAX:           1095 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00282808000msufc0120.fits
SUN_POSTN:        90.22d {+06h 00m 53s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.34 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      173.94d {+11h 35m 46s}   +1.27d {+01d 16' 01"}
MOON_DIST:       142.62 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:22:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.769d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 21"} (J2000)
POINT_ROLL:      79.838d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  83980.03 SOD {23:19:40.03} UT,   120.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.825
N_STARS:         44
X_OFFSET:        592 [pixels]
Y_OFFSET:        136 [pixels]
X_MAX:           1551 [pixels]
Y_MAX:           1095 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00282808000msufc0120.fits
SUN_POSTN:        90.22d {+06h 00m 53s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.34 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      173.94d {+11h 35m 47s}   +1.26d {+01d 15' 54"}
MOON_DIST:       142.61 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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 21 Jun 07 23:23:08 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.769d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 21"} (J2000)
ROLL:            79.838d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  83980.03 SOD {23:19:40.03} UT,   120.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     204160782
X_OFFSET:        858 [pixels]
Y_OFFSET:        566 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1018
Y_GRB_POS:       726
BINNING_INDEX:   1
IM_URL:          sw00282808000msuni0120.fits
SUN_POSTN:        90.22d {+06h 00m 53s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.34 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      173.95d {+11h 35m 48s}   +1.26d {+01d 15' 42"}
MOON_DIST:       142.61 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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 21 Jun 07 23:23:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.769d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 21"} (J2000)
ROLL:            79.838d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  83980.03 SOD {23:19:40.03} UT,   120.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     204160782
X_OFFSET:        858 [pixels]
Y_OFFSET:        566 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1018
Y_GRB_POS:       726
BINNING_INDEX:   1
IM_URL:          sw00282808000msuni0120.fits
SUN_POSTN:        90.22d {+06h 00m 54s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.34 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      173.95d {+11h 35m 49s}   +1.26d {+01d 15' 38"}
MOON_DIST:       142.60 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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 21 Jun 07 23:30:24 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
POINT_ROLL:      79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84085.85 SOD {23:21:25.85} UT,   226.0 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.797
N_STARS:         70
X_OFFSET:        538 [pixels]
Y_OFFSET:        246 [pixels]
X_MAX:           1497 [pixels]
Y_MAX:           1205 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00282808000msufc0226.fits
SUN_POSTN:        90.23d {+06h 00m 55s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.00d {+11h 36m 01s}   +1.23d {+01d 13' 59"}
MOON_DIST:       142.55 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:30:51 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
POINT_ROLL:      79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84085.85 SOD {23:21:25.85} UT,   226.0 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.797
N_STARS:         70
X_OFFSET:        538 [pixels]
Y_OFFSET:        246 [pixels]
X_MAX:           1497 [pixels]
Y_MAX:           1205 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00282808000msufc0226.fits
SUN_POSTN:        90.23d {+06h 00m 55s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.01d {+11h 36m 02s}   +1.23d {+01d 13' 52"}
MOON_DIST:       142.54 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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 21 Jun 07 23:31:37 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
ROLL:            79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84085.85 SOD {23:21:25.85} UT,   226.0 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     204160887
X_OFFSET:        858 [pixels]
Y_OFFSET:        566 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1018
Y_GRB_POS:       726
BINNING_INDEX:   1
IM_URL:          sw00282808000msuni0226.fits
SUN_POSTN:        90.23d {+06h 00m 55s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.01d {+11h 36m 03s}   +1.23d {+01d 13' 41"}
MOON_DIST:       142.54 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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 21 Jun 07 23:31:56 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
ROLL:            79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84085.85 SOD {23:21:25.85} UT,   226.0 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     204160887
X_OFFSET:        858 [pixels]
Y_OFFSET:        566 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1018
Y_GRB_POS:       726
BINNING_INDEX:   1
IM_URL:          sw00282808000msuni0226.fits
SUN_POSTN:        90.23d {+06h 00m 55s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.02d {+11h 36m 04s}   +1.23d {+01d 13' 37"}
MOON_DIST:       142.53 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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 21 Jun 07 23:34:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
POINT_ROLL:      79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84714.43 SOD {23:31:54.43} UT,   854.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.339
N_STARS:         47
X_OFFSET:        538 [pixels]
Y_OFFSET:        246 [pixels]
X_MAX:           1497 [pixels]
Y_MAX:           1205 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00282808000msufc0854.fits
SUN_POSTN:        90.23d {+06h 00m 56s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.04d {+11h 36m 09s}   +1.22d {+01d 12' 56"}
MOON_DIST:       142.51 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:35:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
POINT_ROLL:      79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84714.43 SOD {23:31:54.43} UT,   854.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.339
N_STARS:         47
X_OFFSET:        538 [pixels]
Y_OFFSET:        246 [pixels]
X_MAX:           1497 [pixels]
Y_MAX:           1205 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00282808000msufc0854.fits
SUN_POSTN:        90.23d {+06h 00m 56s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.04d {+11h 36m 09s}   +1.21d {+01d 12' 50"}
MOON_DIST:       142.51 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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 21 Jun 07 23:36:07 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
ROLL:            79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84714.43 SOD {23:31:54.43} UT,   854.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     204161516
X_OFFSET:        857 [pixels]
Y_OFFSET:        565 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1017
Y_GRB_POS:       725
BINNING_INDEX:   1
IM_URL:          sw00282808000msuni0854.fits
SUN_POSTN:        90.23d {+06h 00m 56s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.05d {+11h 36m 11s}   +1.21d {+01d 12' 37"}
MOON_DIST:       142.50 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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:     Thu 21 Jun 07 23:36:30 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
ROLL:            79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84714.43 SOD {23:31:54.43} UT,   854.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     204161516
X_OFFSET:        857 [pixels]
Y_OFFSET:        565 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1017
Y_GRB_POS:       725
BINNING_INDEX:   1
IM_URL:          sw00282808000msuni0854.fits
SUN_POSTN:        90.23d {+06h 00m 56s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.05d {+11h 36m 12s}   +1.21d {+01d 12' 32"}
MOON_DIST:       142.50 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #6560
B. Sbarufatti (INAF-IASFPA), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), P. J. Brown (PSU), M. M. Chester (PSU), C. Guidorzi (Univ Bicocca&INAF-OAB), S. T. Holland (CRESST/GSFC/USRA), J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), C. Pagani (PSU), D. M. Palmer (LANL), P. Romano (Univ. Bicocca & INAF-OAB), M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:
At 23:17:39 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070621 (trigger=282808). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 323.804, -24.806 which is
```
   RA(J2000)  =  21h 35m 13s
   Dec(J2000) = -24d 48' 20"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple peaks with a total duration of at least 40 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~8 sec after the trigger.
The XRT began observing the field at 23:19:30 UT, 111 seconds after the BAT trigger. XRT found a bright and fading X-ray source located at RA, Dec 323.7909, -24.8181 which is
```
   RA(J2000)  =  21h 35m 09.8s  
   Dec(J2000) = -24d 49' 05.1"
```
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 61 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 3.7e-09 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 120 seconds after the BAT trigger. No 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 3-sigma upper limit is about 19.2 mag. The upper limit has not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.05 mag.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:40:43 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
POINT_ROLL:      79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84820.01 SOD {23:33:40.01} UT,   960.2 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        3.663
N_STARS:         49
X_OFFSET:        538 [pixels]
Y_OFFSET:        246 [pixels]
X_MAX:           1497 [pixels]
Y_MAX:           1205 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00282808000msufc0960.fits
SUN_POSTN:        90.24d {+06h 00m 57s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.08d {+11h 36m 19s}   +1.19d {+01d 11' 32"}
MOON_DIST:       142.46 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 21 Jun 07 23:41:09 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
POINT_ROLL:      79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84820.01 SOD {23:33:40.01} UT,   960.2 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        3.663
N_STARS:         49
X_OFFSET:        538 [pixels]
Y_OFFSET:        246 [pixels]
X_MAX:           1497 [pixels]
Y_MAX:           1205 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00282808000msufc0960.fits
SUN_POSTN:        90.24d {+06h 00m 57s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.08d {+11h 36m 20s}   +1.19d {+01d 11' 26"}
MOON_DIST:       142.46 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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 21 Jun 07 23:42:06 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
ROLL:            79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84820.01 SOD {23:33:40.01} UT,   960.2 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     204161622
X_OFFSET:        857 [pixels]
Y_OFFSET:        565 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1017
Y_GRB_POS:       725
BINNING_INDEX:   1
IM_URL:          sw00282808000msuni0960.fits
SUN_POSTN:        90.24d {+06h 00m 57s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.09d {+11h 36m 22s}   +1.19d {+01d 11' 12"}
MOON_DIST:       142.45 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [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:     Thu 21 Jun 07 23:42:25 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     282808,   Seg_Num: 0
POINT_RA:        323.767d {+21h 35m 04s} (J2000)
POINT_DEC:       -24.856d {-24d 51' 20"} (J2000)
ROLL:            79.837d
IMG_START_DATE:  14272 TJD;   172 DOY;   07/06/21
IMG_START_TIME:  84820.01 SOD {23:33:40.01} UT,   960.2 [sec] since BAT Trigger
+Time
FILTER:          3, V
EXPOSURE_ID:     204161622
X_OFFSET:        857 [pixels]
Y_OFFSET:        565 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1017
Y_GRB_POS:       725
BINNING_INDEX:   1
IM_URL:          sw00282808000msuni0960.fits
SUN_POSTN:        90.24d {+06h 00m 57s}  +23.44d {+23d 26' 16"}
SUN_DIST:        131.35 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      174.09d {+11h 36m 22s}   +1.19d {+01d 11' 08"}
MOON_DIST:       142.45 [deg]
MOON_ILLUM:      45 [%]
GAL_COORDS:       24.38,-46.09 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      317.99, -9.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.
COMMENTS:        The GRB Position came from the Window Position in the Mode
+Command.
COMMENTS:        The image has 2x2 binning (compression).
COMMENTS:        All 4 attachments are included.

GCN Circular #6561
E.S. Rykoff (U Mich), W. Rujopakarn (Steward), B. E. Schaefer (Louisiana State), H. Swan (U Mich), J. Aretakis (U Mich), R. Quimby (U Texas), report on behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to GRB 070621 (Swift trigger 282808, Sbarufatti, et al., GCN 6560), producing images beginning 6.1 s after the GCN notice time. An automated response took the first image at 23:18:03.1 UT, 23.3 s after the burst, and during gamma-ray emission. We took 10 5-sec, 10 20-sec and 10 60-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Imaging is ongoing.
Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma Swift/BAT error circle or the XRT error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 16.4-17.8; we set the following specific limits.
```
start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
23:18:03.1   23:18:08.1         5     16.6           23.3       N
23:18:03.1   23:19:20.7        77     17.5           23.3       Y
23:19:28.5   23:24:16.3       287     18.5          108.7       Y
23:24:25.7   23:35:51.6       685     18.8          405.9       Y
```
GCN Circular #6562
John French (University College Dublin), Petr Kubanek (GACE Valencia), Gary Melady (University College Dublin), Martin Jelinek (IAA CSIC Granada)
report on behalf of the Watcher collaboration:
The Watcher 40cm robotic telescope, located at Boyden Observatory, South Africa, began imaging the field of GRB 070621 (Sbarufatti et al., GCN 6560) at 23:18:21 UT, 40s after the Swift trigger.
Our first 10s unfiltered image shows no new source in the XRT error circle down to an R-band limiting magnitude of 16.1. Subsequent 10s exposures were combined to create a 360s exposure with a mean time of 23:21:47 (247s after the trigger). No new source is detected in the XRT error circle down to an R-band limiting magnitude of 17.9. Observations are ongoing.
GCN Circular #6563
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 070621 detected by SWIFT (trigger 282808) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France.
The observations started 23.5s after the GRB trigger (6.4s after the notice). The elevation of the field increased from from 3 degrees above horizon and weather conditions were poor.
The date of trigger : t0 = 2007-06-21T23:17:39.840
The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT at the XRT location (Sbarufatti et al. GCNC 6560) with a limiting magnitude of: t0+23.5s to t0+83.5s : R > 14.9
The second image is 30.0s exposure in tracking mode: t0+90.3s to t0+120.3s : R > 15.4
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
This message may be cited.
GCN Circular #6564
A. Stefanescu (1), Z. Ioannou (2)(4), G. Kanbach (1), S. Duscha (1), F. Schrey (1), A. Slowikowska (2)(3), H. Steinle (1) ((1)=MPE Garching, (2)=FORTH, Heraklion (3)=NCAC, Torun, (4)=Univ. of Crete) of the OPTIMA-Burst Team report the following:
OPTIMA-Burst at the 1.3m Skinakas Observatory, of the University of Crete, Greece observed the Swift XRT error circle of GRB 070621 (GCN Circ 6560, B. Sbarufatti et al.). Observations started at 23:54:52 UT (2233s after the trigger) at an airmass of 2.5.
We see no source at the XRT error circle, neither in single exposures, nor in stacked exposures. Data of the exposures are:
```
t-t_0 (mid exp)  t_exp     R-limit
2263s            60s       20.0         (first exposure)
3271s            1680s     20.9         (stack of all avail. exposures)
```
GCN Circular #6565
D. Malesani, C.C. Thoene, J.P.U. Fynbo (DARK/NBI), N.R. Tanvir (Univ. Leicester), A. Tziamtzis (NOT), report on behalf of a larger collaboration:
We observed the field of GRB 070621 (Sbarufatti et al., GCN 6530) with the NOT equipped with ALFOSC. Observations were carried out in the R and I bands, for a total of 15 min per filter, at mean times 22.17 and 22.184 UT (4.84 and 5.12 hr after the GRB, respectively).
At the edge of the XRT error circle, there is an object at the coordinates (J2000, 0.5" uncertainty):
```
 RA = 21:35:10.07
 Dec = -24:49:07.7
```
with R~22.3 calibrated with respect to the USNO-B1 star 0651-0871887. It might be extended, although the low S/N does not allow firm statements.
No other objects are detected inside the XRT error circle down to R~23.4 and I~22.5.
GCN Circular #6567
B. Sbarufatti (INAF-IASF Pa), P. A. Evans (LU) report on behalf of the Swift team
Using 746 s of overlapping XRT Photon Counting mode and UVOT V-band data, 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 = 323.79225, -24.81752 which is equivalent to:
```
RA (J2000):  21 35 10.10
Dec (J2000): -24 49 03.1
```
with an uncertainty of 2.0 arcsec (90% confidence).
GCN Circular #6568
J. S. Bloom (UC Berkeley), H.-W. Chen (U Chicago), D. A. Perley (UC Berkeley), and L. Pollack (UC Santa Cruz) report:
"The receipt of the BAT_POSITION notice for GRB 070621 (Sbarufatti et al. GCN #6560) triggered our automated imaging program on Gemini South at 23:18:26 UT and the first images were obtained at 22 June 2007 04:54:57 UT by Byran Miller and the Gemini staff once the conditions cleared. Images in griz-bands were obtained, with a total of 5x180 second exposures in each band.
A number of faint sources are detected near the UVOT-enhanced XRT position (Sbarufatti et al., GCN #6567), including the source (s1 = 21:35:10.14, -24:49:06.9) to the South of the XRT position which may be the same source noted by Malesani et al. (GCN #6565). There is an apparent galaxy (s4: 21:35:10.34, -24:49:02.2, PA ~ -45 deg) to the east of the GRB but outside the current XRT position. A color image of the field has been posted (*) along with a ds9 region file (**) giving the J2000 locations of the sources near the GRB.
We note the presence of an asteroid, not found in the Minor Planet Checker (***), moving near the GRB at the time of the Gemini observations. The quickly derived parameters for this asteroid are:
```
  apparent motion: 10.4 S "/hr, 4.69 W "/hr
  position (ecliptic): lambda = +318:07:27.207, beta = -09:53:28.791  @ 
  22 June 2007 05:22:37.4 UTC

(*)   http://lyra.berkeley.edu/~jbloom/grb070621-gemini.png 
(**)  http://lyra.berkeley.edu/~jbloom/grb070621-gemini.reg 
(***) http://scully.harvard.edu/~cgi/CheckSN 
```
We thank Bryan Miller and the Gemini Staff for observing this ToO."
GCN Circular #6569
B. Sbarufatti (INAF-IASFPA), P. Romano, C. Guidorzi (Univ. Bicocca & INAF-OAB) A. Moretti (INAF-OAB) report, on behalf of the Swift-XRT team
We have analysed the first three orbits of Swift XRT data for GRB070621 (Sbarufatti et al., GCN Circ. 6560), consisting of 150 s in Window Timing mode data and 1.3 ks in Photon Counting mode.
The UVOT enhanced XRT position (Sbarufatti et al., GCN Circ. 6567) is RA, Dec = 323.79225, -24.81752 which is equivalent to:
```
RA (J2000):   21 35 10.14
Dec (J2000): -24 49 03.1
```
with an uncertainty of 2.0 arcsec (90% confidence).
The X-ray light curve exhibits an initial steep decay (index -3.8 +/-0.1) up to T+380 s. A flare is observed around T+150s. After the break, the count-rate decays with a power-law index of -0.91 +/- 0.04. If the present slow decay continues, the predicted count rate 24h after the trigger is 2.1E-2 counts/s, corresponding to a flux of 1.8E-12 ergs cm^-2 s^-1.
The WT and PC spectra can be fitted simultaneously with an absorbed power-law model with a photon index 2.5+/-0.3 and a column density (4.4 +/- 0.9)E21 cm^-2, significantly in excess with respect to the galactic value (3.5E20 cm^-2, Dickey & Lockman, 1990). The absorbed (unabsorbed) fluxes are 8.4E-10 (2.2E-09) ergs cm^-2 s^-1 for the WT spectrum and 1.4E-11 (3.6E-11) ergs cm^-2 s^-1 for the PC spectrum.
This circular is an official product of the XRT team.
GCN Circular #6570
N. Tanvir, E. Rol (University of Leicester) and A. Cardwell (ING), report on behalf of a larger collaboration:
We observed the position of GRB070621 (Sbarufatti, GCNC 6560) with the Auxiliary Port Instrument on the William Herschel Telescope at La Palma, for 25 minutes starting at 4:14 UT, June 22 (average time 5.17 hours after burst).
We detect the extended object mentioned by Malesani et al. (GCNC 6565), at a magnitude of I = 21.21 +/- 0.05. We also detect the source on the east edge of the refined XRT error circle (Sbarufatti, GCNC 6569) mentioned by Bloom et al (GCNC 6568), with a magnitude of I = 22.5 +/- 0.1.
Photometry was performed relative to the USNO star 0651-0871887, which has an I2 magnitude of 17.21.
GCN Circular #6571
E. Fenimore (LANL), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), B. Sbarufatti (INAF-IASFPA), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 070621 (trigger #282808) (Sbarufatti, et al., GCN Circ. 6560). The BAT ground-calculated position is RA, Dec = 323.806, -24.809 deg which is
```
   RA(J2000)  =  21h 35m 13.5s 
   Dec(J2000) = -24d 48' 32" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 31%.
The mask-weighted light curve shows several overlapping peaks starting at ~T-20 sec and ending at ~T+40 sec. There is a low-significance bump (~3 sigma) from T+70 to T+105 sec. T90 (15-350 keV) is 33.3 +- 1.0 sec (estimated error including systematics).
The time-averaged spectrum from T-5.2 to T+36.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.57 +- 0.06. The fluence in the 15-150 keV band is 4.3 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+21.56 sec in the 15-150 keV band is 2.5 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #6572
J. S. Bloom (UC Berkeley), L. Pollack (UC Santa Cruz), D. A. Perley (UC Berkeley) report:
"We observed the field of GRB 070621 (GCN #6560) in the K-prime filter using the Laser Guide Star (LGS) Adaptive Optics (AO) system + NIRC2 on the Keck II telescope. With integrations of 60 sec per frame, we stacked 45 frames with a mean time since GRB trigger of 13.8 hr. The brighter compact sources in the field have typical FWHM of 130 mas, and the preliminary 5 sigma detection threshold is K-prime = 21.5 mag. With further refinements we expect this limit to improve.
A number of sources mentioned in previous circulars are detected (*) as well as a few red and faint sources near the XRT position. In particular, we note source l1 (ra=21:35:10.22, dec=-24:49:07.4, J2000) which is 0.8 arcseconds East of apparent galaxy s1 (Bloom et al. GCN #6568 = Malesani et al. source #1 GCN #6565?). The source near the Eastern edge of the XRT position (l2) is nearly coincident with the position of s4 (Bloom et al. GCN #6568 = Tanvir et al. source #2 GCN #6570) but appears only marginally extended at K-prime. Both l1 (being quite red and close to a galaxy) and l2 (appearing nearly point-like and close to the XRT position) are of prime interest in the search for the afterglow of this GRB. Given the large number of sources in the field and the quality of the laser AO images, if either l1 or l2 are confirmed as the GRB afterglow then the astrometric accuracy will be comparable to that obtained previously with early and late HST imaging of other afterglows."
```
(*) http://lyra.berkeley.edu/~jbloom/grb070621_bloom_kecklaser.pdf 
```
We thank the WMKO staff for their assistance in obtaining these observations, especially Randy Campbell and Al Conrad.
GCN Circular #6573
S. T. Holland (CRESST/GSFC/USRA) and B. Sbarufatti (INAF-IASFPA) report on the behalf of the Swift UVOT team:
The Swift/UVOT observed the field of GRB 070621 starting 120 s after the BAT trigger (Sbarufatti, et al. 2007, GCN Circ. 6560). We do not find any source, in any of the UVOT observations, inside the refined XRT error circle (Sbarufatti, et al., 2007 GCN Circ. 6567), or at the location of the NOT source (Malesani, et al. 2007, GCN Circ. 6565).
The 3-sigma upper limits for detecting a source inside the refined XRT error circle in the initial data products are:
```
Filter    T_start   T_stop    Exp(s)    Mag (3-sigma upper limit)
-----------------------------------------------------------------
V             226     1360       806    20.2
B             702      714        10    18.6
U             680     4799        88    19.7
UVW1          656     4744       236    20.3
UVM2          631      802        38    18.8
UVW2          733      752        19    18.1
White         120      954       204    21.3
-----------------------------------------------------------------
```
The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E_{B-V} = 0.05 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #6574
P. D'Avanzo (INAF - OABr) V. D'Elia (INAF - OAR), D. Fugazza, G. Tagliaferri (INAF - OABr) on behalf of the MISTICI collaboration and D. Malesani and J.P.U. Fynbo (DARK/NBI) report:
We observed the field of GRB070621 (Sbarufatti et al., GCN 6560) with the ESO-VLT equipped with the FORS1 camera in the R and I bands. Observations were carried out on Jun 22.36 and 22.38 UT (0.39 and 0.41 days after the GRB) in the I and R filters, respectively.
We detect two extended sources near the revised XRT error box (Sbarufatti et al. GCN 6569), reported by different authors (Malesani et al. GCN 6565, Tanvir et al. GCN 6570, Bloom et al. GCN 6568 and GCN 6572), at the following coordinates (J2000):
```
S1) R.A. = 21:35:10.08, Dec. = -24:49:07.5
S2) R.A. = 21:35:10.27, Dec. = -24:49:02.8
```
with an uncertainty of 0.4".
A comparison between the NOT (Malesani et al. GCN 6565) and VLT images shows that source S1 remained constant between the NOT and VLT observation up to 0.1 mag.
Source S2 is not visible in the NOT image, so that a direct comparison is not possible. When considering the roughly simultaneous WHT I-band measurement by Tanvir et al. (GCN 6570), we note a small discrepancy (~0.5 mag) in the magnitude of source S1. After taking into account this uncertainty, no variability can be claimed for source S2 as well.
Source S1 appears elongated in the East/West direction, consistent with the superposition of two objects as resolved in the adaptive-optics Keck image (Bloom et al. GCN 6572).
We acknowledge the support of the ESO staff.
This message can be quoted.
GCN Report 67.1
GCN_Report 67.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_67_1.pdf by B. Sbarufatti at INAF-IASFPA titled: "Swift observations of GRB 070621"
GCN Circular #6575
I. Khamitov (TUG), I. Bikmaev, N. Sakhibullin (KSU/AST), Z. Tunca (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI)
reports:
We observed the field of GRB 070621 (Sbarufatti et al., GCN 6530) with Russian-Turkish 1.5-m telescope (RTT150, Bakyrlytepe,TUBITAK National Observatory, Turkey). We made 16x60s exposures in R band, starting at June 21, 23:25:40UT, i.e. approximately 500 s after the burst.
We detected no sources inside the XRT error circle in any of 60~s image, as well as in combined 16x60~s image with 3-sigma limiting magnitudes m_R=~20.8 and m_R=~22.3 respectively.
The source reported by Melesani et al (GCN 6565) is clearly detected on the level m_R=22.15+/-0.2 using the same reference star USNO-B1 0651-0871887, i.e. is not variable within the errors. The astrometric position of this source is RA=21:35:10.12, DEC=-24:49:07.2 with 0.1 arcsec accuracy.
The sourse to the east from XRT position, which was found in Gemini South data (s4, Bloom et. al., GCN 6568), and in image from Keck II LGS AO (i2, Bloom et. al., GCN 6572) is also detected marginally near the limit of our combined image.
This message may be cited.
GCN Report 67.2
GCN_Report 67.2 has been posted: http://gcn.gsfc.nasa.gov/reports/report_67_2.pdf by B. Sbarufatti at INAF-IASFPA titled: "Final Swift observations of GRB 070621"
arXiv:1504.02482 putative R-band detection by TOUGH and XRT NH excess: implies z<5.5

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Jochen Greiner, last update: 07-Jul-2015 [Disclaimer]