Gamma-ray Burst 080605

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 05 Jun 08 23:48:11 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     313299,   Seg_Num: 0
GRB_RA:          262.127d {+17h 28m 31s} (J2000),
                 262.232d {+17h 28m 56s} (current),
                 261.506d {+17h 26m 01s} (1950)
GRB_DEC:          +4.002d {+04d 00' 06"} (J2000),
                  +3.995d {+03d 59' 43"} (current),
                  +4.041d {+04d 02' 28"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       12879 [cnts]    Image_Peak=1604 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   147     E_range: 50-350 keV
BKG_INTEN:       39042 [cnts]
BKG_TIME:        85661.15 SOD {23:47:41.15} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14622 TJD;   157 DOY;   08/06/05
GRB_TIME:        85677.85 SOD {23:47:57.85} UT
GRB_PHI:          63.90 [deg]
GRB_THETA:        29.58 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     120.74 [sigma]
IMAGE_SIGNIF:    25.82 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +3 +27  +0  +0 +88  +1 
SUN_POSTN:        74.43d {+04h 57m 43s}  +22.67d {+22d 39' 57"}
SUN_DIST:        152.27 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.33d {+07h 13m 20s}  +25.29d {+25d 17' 30"}
MOON_DIST:       141.28 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.88, 20.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      261.16, 27.20 [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 = 10.94,-0.73 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 05 Jun 08 23:53:03 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     313299,   Seg_Num: 0
GRB_RA:          262.127d {+17h 28m 31s} (J2000),
                 262.232d {+17h 28m 56s} (current),
                 261.506d {+17h 26m 01s} (1950)
GRB_DEC:          +4.002d {+04d 00' 06"} (J2000),
                  +3.995d {+03d 59' 43"} (current),
                  +4.041d {+04d 02' 28"} (1950)
GRB_DATE:        14622 TJD;   157 DOY;   08/06/05
GRB_TIME:        85677.85 SOD {23:47:57.85} UT
TRIGGER_INDEX:   147
GRB_PHI:          63.90 [deg]
GRB_THETA:        29.58 [deg]
DELTA_TIME:      320.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     120.74 [sigma]
IMAGE_SIGNIF:    25.82 [sigma]
LC_URL:          sw00313299000msb.lc
SUN_POSTN:        74.43d {+04h 57m 44s}  +22.67d {+22d 39' 59"}
SUN_DIST:        152.27 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.39d {+07h 13m 33s}  +25.28d {+25d 16' 55"}
MOON_DIST:       141.25 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.88, 20.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      261.16, 27.20 [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 = 10.94,-0.73 [deg].  
COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:03:16 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     313299,   Seg_Num: 0
GRB_RA:          262.1249d {+17h 28m 29.9s} (J2000),
                 262.2296d {+17h 28m 55.1s} (current),
                 261.5038d {+17h 26m 00.9s} (1950)
GRB_DEC:          +4.0153d {+04d 00' 55.0"} (J2000),
                  +4.0089d {+04d 00' 32.0"} (current),
                  +4.0549d {+04d 03' 17.7"} (1950)
GRB_ERROR:       5.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.75e-09 [erg/cm2/sec]
GRB_SIGNIF:      7.93 [sigma]
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85768.24 SOD {23:49:28.24} UT,   90.4 [sec] since BAT Trigger Time
TAM[0-3]:        327.63 237.19 261.36 243.53
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        74.44d {+04h 57m 46s}  +22.67d {+22d 40' 01"}
SUN_DIST:        152.26 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.50d {+07h 14m 00s}  +25.26d {+25d 15' 41"}
MOON_DIST:       141.18 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.89, 20.26 [deg] galactic lon,lat of the burst
ECL_COORDS:      261.16, 27.21 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.83 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:03:26 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     313299,   Seg_Num: 0
GRB_RA:          262.1249d {+17h 28m 29.9s} (J2000),
                 262.2296d {+17h 28m 55.1s} (current),
                 261.5038d {+17h 26m 00.9s} (1950)
GRB_DEC:          +4.0153d {+04d 00' 55.0"} (J2000),
                  +4.0089d {+04d 00' 32.0"} (current),
                  +4.0549d {+04d 03' 17.7"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       63 [cnts]
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85768.24 SOD {23:49:28.24} UT,   90.4 [sec] since BAT Trigger Time
CENTROID_X:      261.11,  raw= 261  [pixels]
CENTROID_Y:      303.15,  raw= 303  [pixels]
ROLL:            15.42 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   12.14
GRB_POS_XRT_Z:   -97.08
IMAGE_URL:       sw00313299000msxps_rw.img
SUN_POSTN:        74.44d {+04h 57m 46s}  +22.67d {+22d 40' 01"}
SUN_DIST:        152.26 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.50d {+07h 14m 01s}  +25.26d {+25d 15' 40"}
MOON_DIST:       141.18 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.89, 20.26 [deg] galactic lon,lat of the burst
ECL_COORDS:      261.16, 27.21 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:03:34 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     313299,   Seg_Num: 0
GRB_RA:          262.1249d {+17h 28m 29.9s} (J2000),
                 262.2296d {+17h 28m 55.1s} (current),
                 261.5038d {+17h 26m 00.9s} (1950)
GRB_DEC:          +4.0153d {+04d 00' 55.0"} (J2000),
                  +4.0089d {+04d 00' 32.0"} (current),
                  +4.0549d {+04d 03' 17.7"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       63 [cnts]
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85768.24 SOD {23:49:28.24} UT,   90.4 [sec] since BAT Trigger Time
CENTROID_X:      261.11,  raw= 261  [pixels]
CENTROID_Y:      303.15,  raw= 303  [pixels]
ROLL:            15.42 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   12.14
GRB_POS_XRT_Z:   -97.08
IMAGE_URL:       sw00313299000msxps_rw.img
SUN_POSTN:        74.44d {+04h 57m 46s}  +22.67d {+22d 40' 01"}
SUN_DIST:        152.26 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.50d {+07h 14m 01s}  +25.26d {+25d 15' 39"}
MOON_DIST:       141.18 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.89, 20.26 [deg] galactic lon,lat of the burst
ECL_COORDS:      261.16, 27.21 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:04:13 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.121d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.988d {+03d 59' 18"} (J2000)
POINT_ROLL:      15.423d
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85777.80 SOD {23:49:37.80} UT,   99.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.589
N_STARS:         184
X_OFFSET:        584 [pixels]
Y_OFFSET:        528 [pixels]
X_MAX:           1543 [pixels]
Y_MAX:           1487 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00313299000msufc0099.fits
SUN_POSTN:        74.44d {+04h 57m 46s}  +22.67d {+22d 40' 01"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.51d {+07h 14m 03s}  +25.26d {+25d 15' 34"}
MOON_DIST:       141.19 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:04:53 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.121d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.988d {+03d 59' 18"} (J2000)
POINT_ROLL:      15.423d
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85777.80 SOD {23:49:37.80} UT,   99.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.589
N_STARS:         184
X_OFFSET:        584 [pixels]
Y_OFFSET:        528 [pixels]
X_MAX:           1543 [pixels]
Y_MAX:           1487 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00313299000msufc0099.fits
SUN_POSTN:        74.44d {+04h 57m 46s}  +22.67d {+22d 40' 02"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.52d {+07h 14m 05s}  +25.26d {+25d 15' 30"}
MOON_DIST:       141.19 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:05:46 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.121d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.988d {+03d 59' 18"} (J2000)
ROLL:            15.423d
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85777.80 SOD {23:49:37.80} UT,   99.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     234402580
X_OFFSET:        956 [pixels]
Y_OFFSET:        768 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1116
Y_GRB_POS:       928
BINNING_INDEX:   1
IM_URL:          sw00313299000msuni0099.fits
SUN_POSTN:        74.44d {+04h 57m 46s}  +22.67d {+22d 40' 02"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.53d {+07h 14m 07s}  +25.26d {+25d 15' 23"}
MOON_DIST:       141.19 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:05:16 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.121d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.988d {+03d 59' 18"} (J2000)
ROLL:            15.423d
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85777.80 SOD {23:49:37.80} UT,   99.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     234402580
X_OFFSET:        956 [pixels]
Y_OFFSET:        768 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1116
Y_GRB_POS:       928
BINNING_INDEX:   1
IM_URL:          sw00313299000msuni0099.fits
SUN_POSTN:        74.44d {+04h 57m 46s}  +22.67d {+22d 40' 02"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.52d {+07h 14m 06s}  +25.26d {+25d 15' 27"}
MOON_DIST:       141.19 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:08:31 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
POINT_ROLL:      15.421d
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85883.80 SOD {23:51:23.80} UT,   205.9 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.588
N_STARS:         190
X_OFFSET:        636 [pixels]
Y_OFFSET:        448 [pixels]
X_MAX:           1595 [pixels]
Y_MAX:           1407 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00313299000msufc0205.fits
SUN_POSTN:        74.45d {+04h 57m 47s}  +22.67d {+22d 40' 03"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.56d {+07h 14m 14s}  +25.25d {+25d 15' 03"}
MOON_DIST:       141.17 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:09:11 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
POINT_ROLL:      15.421d
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85883.80 SOD {23:51:23.80} UT,   205.9 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.588
N_STARS:         190
X_OFFSET:        636 [pixels]
Y_OFFSET:        448 [pixels]
X_MAX:           1595 [pixels]
Y_MAX:           1407 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00313299000msufc0205.fits
SUN_POSTN:        74.45d {+04h 57m 47s}  +22.67d {+22d 40' 03"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.57d {+07h 14m 16s}  +25.25d {+25d 14' 59"}
MOON_DIST:       141.17 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:09:50 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
ROLL:            15.421d
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85883.80 SOD {23:51:23.80} UT,   205.9 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     234402686
X_OFFSET:        956 [pixels]
Y_OFFSET:        768 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1116
Y_GRB_POS:       928
BINNING_INDEX:   1
IM_URL:          sw00313299000msuni0205.fits
SUN_POSTN:        74.45d {+04h 57m 47s}  +22.67d {+22d 40' 03"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.57d {+07h 14m 18s}  +25.25d {+25d 14' 54"}
MOON_DIST:       141.16 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:10:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
ROLL:            15.421d
IMG_START_DATE:  14622 TJD;   157 DOY;   08/06/05
IMG_START_TIME:  85883.80 SOD {23:51:23.80} UT,   205.9 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     234402686
X_OFFSET:        956 [pixels]
Y_OFFSET:        768 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1116
Y_GRB_POS:       928
BINNING_INDEX:   1
IM_URL:          sw00313299000msuni0205.fits
SUN_POSTN:        74.45d {+04h 57m 47s}  +22.67d {+22d 40' 03"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.58d {+07h 14m 19s}  +25.25d {+25d 14' 50"}
MOON_DIST:       141.16 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:10:50 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
POINT_ROLL:      15.421d
IMG_START_DATE:  14623 TJD;   158 DOY;   08/06/06
IMG_START_TIME:  133.48 SOD {00:02:13.48} UT,   855.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.721
N_STARS:         182
X_OFFSET:        636 [pixels]
Y_OFFSET:        448 [pixels]
X_MAX:           1595 [pixels]
Y_MAX:           1407 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00313299000msufc0855.fits
SUN_POSTN:        74.45d {+04h 57m 47s}  +22.67d {+22d 40' 03"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.59d {+07h 14m 20s}  +25.25d {+25d 14' 47"}
MOON_DIST:       141.16 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:11:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
POINT_ROLL:      15.421d
IMG_START_DATE:  14623 TJD;   158 DOY;   08/06/06
IMG_START_TIME:  133.48 SOD {00:02:13.48} UT,   855.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.721
N_STARS:         182
X_OFFSET:        636 [pixels]
Y_OFFSET:        448 [pixels]
X_MAX:           1595 [pixels]
Y_MAX:           1407 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00313299000msufc0855.fits
SUN_POSTN:        74.45d {+04h 57m 47s}  +22.67d {+22d 40' 03"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.59d {+07h 14m 22s}  +25.24d {+25d 14' 42"}
MOON_DIST:       141.15 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:12:07 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
ROLL:            15.421d
IMG_START_DATE:  14623 TJD;   158 DOY;   08/06/06
IMG_START_TIME:  133.48 SOD {00:02:13.48} UT,   855.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     234403336
X_OFFSET:        955 [pixels]
Y_OFFSET:        767 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1115
Y_GRB_POS:       927
BINNING_INDEX:   1
IM_URL:          sw00313299000msuni0855.fits
SUN_POSTN:        74.45d {+04h 57m 47s}  +22.67d {+22d 40' 04"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.60d {+07h 14m 24s}  +25.24d {+25d 14' 37"}
MOON_DIST:       141.15 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:12:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
ROLL:            15.421d
IMG_START_DATE:  14623 TJD;   158 DOY;   08/06/06
IMG_START_TIME:  133.48 SOD {00:02:13.48} UT,   855.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     234403336
X_OFFSET:        955 [pixels]
Y_OFFSET:        767 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1115
Y_GRB_POS:       927
BINNING_INDEX:   1
IM_URL:          sw00313299000msuni0855.fits
SUN_POSTN:        74.45d {+04h 57m 48s}  +22.67d {+22d 40' 04"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.60d {+07h 14m 25s}  +25.24d {+25d 14' 34"}
MOON_DIST:       141.15 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:14:48 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
POINT_ROLL:      15.421d
IMG_START_DATE:  14623 TJD;   158 DOY;   08/06/06
IMG_START_TIME:  240.32 SOD {00:04:00.32} UT,   962.5 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.682
N_STARS:         190
X_OFFSET:        636 [pixels]
Y_OFFSET:        448 [pixels]
X_MAX:           1595 [pixels]
Y_MAX:           1407 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00313299000msufc0962.fits
SUN_POSTN:        74.45d {+04h 57m 48s}  +22.67d {+22d 40' 04"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.63d {+07h 14m 31s}  +25.24d {+25d 14' 18"}
MOON_DIST:       141.13 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:16:07 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
ROLL:            15.421d
IMG_START_DATE:  14623 TJD;   158 DOY;   08/06/06
IMG_START_TIME:  240.32 SOD {00:04:00.32} UT,   962.5 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     234403443
X_OFFSET:        955 [pixels]
Y_OFFSET:        767 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1115
Y_GRB_POS:       927
BINNING_INDEX:   1
IM_URL:          sw00313299000msuni0962.fits
SUN_POSTN:        74.45d {+04h 57m 48s}  +22.67d {+22d 40' 05"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.64d {+07h 14m 35s}  +25.24d {+25d 14' 08"}
MOON_DIST:       141.13 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:16:38 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
ROLL:            15.421d
IMG_START_DATE:  14623 TJD;   158 DOY;   08/06/06
IMG_START_TIME:  240.32 SOD {00:04:00.32} UT,   962.5 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     234403443
X_OFFSET:        955 [pixels]
Y_OFFSET:        767 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1115
Y_GRB_POS:       927
BINNING_INDEX:   1
IM_URL:          sw00313299000msuni0962.fits
SUN_POSTN:        74.45d {+04h 57m 48s}  +22.67d {+22d 40' 05"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.65d {+07h 14m 36s}  +25.23d {+25d 14' 05"}
MOON_DIST:       141.12 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_sources_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:15:33 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     313299,   Seg_Num: 0
POINT_RA:        262.120d {+17h 28m 29s} (J2000)
POINT_DEC:        +3.989d {+03d 59' 21"} (J2000)
POINT_ROLL:      15.421d
IMG_START_DATE:  14623 TJD;   158 DOY;   08/06/06
IMG_START_TIME:  240.32 SOD {00:04:00.32} UT,   962.5 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.682
N_STARS:         190
X_OFFSET:        636 [pixels]
Y_OFFSET:        448 [pixels]
X_MAX:           1595 [pixels]
Y_MAX:           1407 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00313299000msufc0962.fits
SUN_POSTN:        74.45d {+04h 57m 48s}  +22.67d {+22d 40' 04"}
SUN_DIST:        152.29 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.64d {+07h 14m 33s}  +25.24d {+25d 14' 12"}
MOON_DIST:       141.13 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.86, 20.25 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.16, 27.19 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 06 Jun 08 00:27:37 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     313299,   Seg_Num: 0
GRB_RA:          262.1257d {+17h 28m 30.1s} (J2000),
                 262.2304d {+17h 28m 55.3s} (current),
                 261.5046d {+17h 26m 01.1s} (1950)
GRB_DEC:          +4.0162d {+04d 00' 58.3"} (J2000),
                  +4.0098d {+04d 00' 35.3"} (current),
                  +4.0558d {+04d 03' 21.0"} (1950)
GRB_ERROR:       2.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  14623 TJD;   158 DOY;   08/06/06
IMG_START_TIME:  199.00 SOD {00:03:19.00} UT,   921.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        74.46d {+04h 57m 50s}  +22.67d {+22d 40' 07"}
SUN_DIST:        152.26 [deg]   Sun_angle= 11.5 [hr] (West of Sun)
MOON_POSTN:      108.77d {+07h 15m 05s}  +25.21d {+25d 12' 45"}
MOON_DIST:       141.04 [deg]
MOON_ILLUM:      7 [%]
GAL_COORDS:       26.89, 20.26 [deg] galactic lon,lat of the burst
ECL_COORDS:      261.16, 27.21 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry

GCN Circular #7828
B. Sbarufatti (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), V. La Parola (INAF-IASFPA), V. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (NASA/UMBC), T. N. Ukwatta (GSFC/GWU) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 23:47:57 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080605 (trigger=313299). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 262.127, +4.002 which is
```
   RA(J2000)  = 17h 28m 31s
   Dec(J2000) = +04d 00' 06"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple overlapping peaks lasting at least to T+8 sec (at which the TDRSS lightcurve is truncated). The peak count rate was ~17000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 23:49:28.2 UT, 90.4 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 262.1249, +4.0153 which is equivalent to:
```
   RA(J2000)  = 17h 28m 29.9s
   Dec(J2000) = +04d 00' 55.0"
```
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 48 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
The UVOT detects a new source within the XRT error circle. We are unable to obtain a position or magnitude at this time. The source is very close to a known source in the DSS. Further information will be provided when it is available.
Burst Advocate for this burst is B. Sbarufatti (sbarufatti AT ifc.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular #7829
D. A. Kann, U. Laux, S. Klose, S. Ertel (TLS Tautenburg) and J. Greiner (Garching) report:
We observed the location of Swift GRB 080605 with the TLS Tautenburg 1.34m Schmidt telescope in RRM Mode (Klose et al., GCN 3609).
At the in-flight XRT position, in a 120 sec Ic band frame, we detect a new source not present in the DSS at:
RA (J2000) = 17:28:29.96 Dec. (J2000) = +04:00:57.5
The source is blended with a star to the southeast but clearly discernible.
We propose this to be the afterglow of GRB 080605. Spectroscopy is encouraged.
This message may be cited.
GCN Circular #7830
S. T. Holland (CRESST/USRA/GSFC) and B. Sbarufatti (INAF-IASFPA) report on behalf of the Swift Team:
Swift/UVOT began observing the field of GRB 080605 (Sbarufatti et al. 2008, GCN Circ. 7828) with a 99 s white exposure starting 104 s after the BAT trigger. The preliminary Swift/UVOT position of the optical afterglow candidate is
```
  RA(J2000.0) =  17:28:30.07
Dec(J2000.0) = +04:00:56.0
```
with an estimated position uncertainty of 1.0 arcsec. There is a known source (USNO-B1.0 940-028965) 3 arcsec from this position.
GCN Circular #7831
A. Gomboc (U. Ljubljana), A. Melandri, R.J. Smith, C.G. Mundell, I.A. Steele, D. Bersier, S. Kobayashi, D. Carter, M. Burgdorf, M.F. Bode (Liverpool JMU), C. Guidorzi (INAF-OAB) report:
The Liverpool Telescope (La Palma) automatically reacted to the Swift trigger 313299 and started observing the field 3 min after the trigger.
We find an un-catalogues source at
```
RA 17:28:29.9,
dec +04:00:55.0
```
consistent with the XRT position.
The magnitude of the source is R=18.3 at 11.3 min after the trigger.
GCN Circular #7832
Pall Jakobsson (U. Hertfordshire), Paul M. Vreeswijk, Dong Xu and Christina C. Thoene (DARK, NBI) report on behalf of a larger collaboration:
Using FORS2 on the Very Large Telescope, we have obtained a 10 min spectrum (grism 300V) of the optical afterglow of GRB 080605 (Sbarufatti et al., GCN 7828). The acquisition image shows it to have R = 20.4 on June 6.063 (1.7 hours post burst).
A firm upper limit of z < 2.1 can be placed on the redshift of GRB 080605 from the lack of Ly-alpha forest lines in the spectrum of the afterglow.
The spectrum is rich in absorption features, including Si II, C IV, Al II, Al III, Zn II, Fe II, Mg II and Mg I, corresponding to a redshift of z = 1.6398 +/- 0.0006.
We thank the Paranal staff for excellent support, especially Linda Schmidtobreick.
GCN Circular #7833
V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the optical afterglow (Kann, et al., GCN 7829; Holland et al., GCN 7830; Gomboc et al., GCN 7831) of Swift GRB 080605 (Sbarufatti et al., GCN 7828) in R and I bands on June 05 Zeiss-1000 (Simeiz) telescope of CrAO observatory under not optimal weather conditions. Based on USNO-B1.0 star RA (J2000) = 17 28 29.92, Dec. (J2000) = +04 00 36.5, R2=15.90 we estimated brightness of the optical afterglow in first frames:
```
UT,       Exposure,   R_mag,
(start time)

2008-06-05T23:55:58    120 s     17.9
2008-06-06T00:00:34    120 s     18.4
```
During observations the afterglow is clearly faded. Coordinates of the afterglow with uncertainties of 0.3":
```
RA(2000):  17 28 30.01
Dec(2000): +04 00 56.4
```
A finding chart can be found at http://grb.rssi.ru/GRB080605/grb080605_080605_z1000.gif The message may be cited.
GCN Circular #7834
C. Clemens, T. Kruehler, J. Greiner, A. Kupcu Yoldas, A. Yoldas (all MPE Garching) and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 080605 (Swift trigger 313299; Sbarufatti et al., GCN #7828) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile).
Observations started at 01:10:59 UT on June 6th, 2008, 83 mins after the GRB trigger, and are continuing.
We found a single and relatively bright point source within the 1.0'' Swift-UVOT error circle reported by Holland et al. (GCN #7830) at
```
RA (J2000.0) = 17h 28m 30.05s
DEC (J2000.0) = +04d 00' 56.2"
```
with a typical uncertainty of 0.8", which is consistent with the sources reported by Kann et al. (GCN #7829) and Gomboc et al. (GCN #7831).
Based on 460 s and 1500 s of effective exposures taken 1.65 hrs and 2.78 hrs after the trigger, we estimate preliminary magnitudes of
```
r' = 20.3 and i' = 19.4, as well as
r' = 20.7 and i' = 19.9
```
with typical errors of +/- 0.1. (Given magnitudes are calibrated against USNO-B1 field stars and might be affected by the bright, nearby star.)
This indicates a clear fading of the source, which we therefore suggest to be the optical afterglow of GRB 080605.
GCN Circular #7835
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 426 s of overlapping XRT Photon Counting mode and UVOT data for GRB 080605, 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 = 262.12533, +4.01608 which is equivalent to:
```
RA (J2000): 17h 28m 30.08s
Dec (J2000): +04d 00' 57.9"
```
with an uncertainty of 1.8 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 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method.
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #7836
MASTER-Net Team:
D.Kuvshinov, V. Lipunov, V.Kornilov, E.Gorbovskoy, A.Belinski, N.Shatskiy, N.Tyurina, Sternberg Astronomical Institute, Moscow Union 'Optic'
A. Tlatov, I.Golubov Kislovodsk Solar Station of the Pulkovo observatory
V.Krushinski, I.Zalognikh Ural State University, Kourovka
S.Yazev, K.Ivanov Irkutsk State University
MASTER Very Wide Field Camera located at Kislovodsk Solar Station (http://observ.pereplet.ru, D=50 mm, 1015 square degrees, 35'' per pix) has moved to the Swift-BAT trigger 313299 (23:47:57 UT) and it has taken a series of 5s exposures starting 46s after the GRB time and 12 s after notice arrivel time at 23:48:43 UT under good weather condition, but large zenit distance.
These unfiltered images are calibrated relative to USNO A2.0 (R). There is no OT was found inside Swift error box (B. Sbarufatti, S. D. Barthelmy et al., GCN Circ 7828).
T-Tgrb Mean Time Limit Coadd? Note
46s 48.5s >9.0 no moving
51s 53.5s >10.0 no
51s 56.0s >10.2 2
51s 76.0s >11.0 10
51s 101.0s >11.5 20
The message can be cited. mailto: lipunov@sai.msu.ru
PS. AT = After Trigger
GCN Circular #7837
M. Jelinek, A.J.Castro-Tirado, J. Gorosabel (IAA CSIC Granada), Petr Kubanek (GACE Valencia), S. Vitek (FEL CVUT Praha), A. de Ugarte Postigo (ESO Santiago), on behalf of a larger Collaboration:
report:
"We observed the optical afterglow of GRB 080605 (Kann et al. GCN 7829, Sbarufatti et al. GCN 7828, Gomboc et al. GCN 7831) with the 30cm BOOTES-1B and with the 60cm BOOTES-2/TELMA robotic telescopes in southern Spain.
The sequence of observations started 43s after the GRB trigger. We clearly detect a 15th mag transient outshining the nearby star in R-band (BOOTES-2/TELMA) and without filter (BOOTES-1B). "
GCN Circular #7838
B. Sbarufatti, V. Mangano, V. La Parola (INAF-IASF Pa) report on behalf of the Swift-XRT team
The XRT began observations of GRB 080605 (trigger=313299, Sbarufatti et al., GCN circ. 7828) started on 2008 May 05 at 23:49:36 UT, 97 s after the BAT trigger. The data consist of 642 s in Windowed Timing mode and 4.3 ks s in Photon Counting mode.
The light curve is described by a powerlaw with initial slope 0.65 (+/-0.05) until T+ 280s (+90, - 45), at which point the decay steepens to an index 1.32 (+/-0.03).
The spectrum of the WT mode data can be fitted by a powerlaw with photon index 1.78 (+/- 0.04) and an intrinsic absorbing column of 6.6 (+/-0.9)E21 cm^-2 at z=1.6398 (Jakobsson et al., GCN circ. 7832), in excess over the Galactic value of 6.67E20 cm^-2. The observed (unabsorbed) flux is 7.5 (8.1)E-10 erg cm^-2 s^-1. The first orbit PC mode spectrum (379 s of exposure) can be fit by a powerlaw with photon index 1.6 (+/- 0.2) and an intrinsic absorbing column of 4.8 (+/-4)E21 cm^-2. The observed (unabsorbed) flux is 3.0 (3.3)E-10 erg cm^-2 s^-1.
The countrate to flux conversion factor is 4.87e-11 erg cm^-2 s^-1. The predicted countrate 24 h after the trigger is 1.6E-2 counts/s, equivalent to an observed flux of 7.8E-13 erg cm^-2 cts^-1.
This circular is an official product of the Swift-XRT team.
GCN Circular #7839
J. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), B. Sbarufatti (INAF-IASFPA), 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 080605 (trigger #313299) (Sbarufatti, et al., GCN Circ. 7828). The BAT ground-calculated position is RA, Dec = 262.130, 4.010 deg, which is
```
   RA(J2000)  =  17h 28m 31.1s 
   Dec(J2000) = +04d 00' 35.6" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%.
The mask-weighted light curve shows a cluster of overlapping peaks starting at ~T-3 sec, the largest peak at ~T+8 sec, and all ending at ~T+70 sec. At the 1-2 sigma level, there is appears to be persistant emmission in the T+300 to T+700 sec range. T90 (15-350 keV) is 20 +- 1 sec (estimated error including systematics).
The time-averaged spectrum from T-5.5 to T+30.0 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.11 +- 0.14, and Epeak of 223 +- 133 keV (chi squared 28.10 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.33 +- 0.02 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+7.57 sec in the 15-150 keV band is 19.9 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.36 +- 0.03 (chi squared 37 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/313299/BA/
GCN Circular #7841
J. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), B. Sbarufatti (INAF-IASFPA), 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 080605 (trigger #313299) (Sbarufatti, et al., GCN Circ. 7828). The BAT ground-calculated position is RA, Dec = 262.130, 4.010 deg, which is
```
   RA(J2000)  =  17h 28m 31.1s 
   Dec(J2000) = +04d 00' 35.6" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%.
The mask-weighted light curve shows a cluster of overlapping peaks starting at ~T-3 sec, the largest peak at ~T+8 sec, and all ending at ~T+70 sec. At the 1-2 sigma level, there is appears to be persistant emmission in the T+300 to T+700 sec range. T90 (15-350 keV) is 20 +- 1 sec (estimated error including systematics).
The time-averaged spectrum from T-5.5 to T+30.0 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.11 +- 0.14, and Epeak of 223 +- 133 keV (chi squared 28.10 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.33 +- 0.02 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+7.57 sec in the 15-150 keV band is 19.9 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.36 +- 0.03 (chi squared 37 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/313299/BA/
GCN Circular #7844
N. P. M. Kuin (MSSL/UCL), B. Sbarufatti (INAF-IASFPA), F. Marshall (GSFC), and P.Schady (MSSL/UCL), report on behalf of the Swift UVOT team
The Swift UltraViolet/Optical Telescope (UVOT) began observations of GRB 080605, on June 5, 2008, at 23:49:19 UT, 82 seconds after the initial Swift BAT trigger (Mangano et al., GCN Circ. 7794), and started the finding chart exposure in the white filter at 102 seconds after the trigger.
The refined uvot position of GRB080605 is RA=262.12522, Dec=+4.01555 deg.(= 17:28:30.05 +04:00:55.97), with an accuracy of 0.5", consistent with the positions reported in GCN Circ. 7830 (Holland et al.) and 7835 (Goad et al.).
The GRB is found close (about 4" distant) to a star, which may cause an error in the measured flux, especially at later times. For this analysis we use a small 2" aperture which which reduces the contamination, and apply a standard aperture correction. We note that the DSS image indicates the presence of a weak, possibly extended source near the position of the afterglow.
The magnitudes with 1-sigma errors for GRB080605 are given below for the initial observation sequence.
```
Filter Tstart(s) Tstop(s) Exp(s) Magnitude

wh      102      201     98.2    18.11 +/- 0.06
v       208      607    393.5    18.53 +/- 0.11
wh      858      957     98.2    20.02 +/- 0.17
uvm2    615      788     38.9   >18.38 (3 sigma UL)
uvw1    639      813     38.9   >18.95 (3 sigma UL)
uvw2    720      739     19.5   >18.16 (3 sigma UL)
b     27679    28264    571.7    21.10 +/- 0.27
u     18432    41856    550.7    21.17 +/- 0.43
```
The values quoted above are on the UVOT Photometric System (Poole et al, 2008, MNRAS 383,627). They are not corrected for the expected galactic reddening of E(B-V) = 0.137 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #7845
D. A. Kann, U. Laux and S. Ertel (TLS Tautenburg) report:
We continue observations of the afterglow of GRB 080605 (independently discovered by Sbarufatti et al., GCN 7828, Kann et al., GCN 7829, and Gomboc et al., GCN 7831). We acquired one 300 sec image each in V, R, and I around 0.95 days after the GRB, and further imaging 0.1 days later until dawn. Astonishingly, the afterglow is still clearly visible in R and I bands.
As mentioned in the above-cited GCNs, the afterglow is close to a star and affected by its PSF in images with low-quality seeing or large pixel scale, such as the TLS camera. To obtain a qualitative description of the afterglow evolution, we perform aperature photometry in a 3 pixel aperature, and derive the aperature correction for each image by comparing the counts for a reference star in the 3 pixel aperature with that in a 7 pixel (which is typically seeing-matched) aperature. As a reference star, we use the star to the south of the afterglow, USNOB1.0 ID 0940-0289655 at (catalog position): RA = 17:28:29.920, Dec. = +04:00:36.51, which has R2 = 15.90 mag, I = 14.54 mag. We derive the following magnitudes for selected images in the I band (the error is estimated to be 0.1 magnitudes in all cases):
```
dt		I

0.00478791	16.74
0.00674681	17.18
0.00869923	17.36
0.01064872	17.61
0.01849396	18.19
0.02433042	18.19
0.05922051	18.48
0.96109933	18.51
1.05275325	18.71
```
The early afterglow decay (0.00479 to 0.01849 days) is well-described by a power-law with decay slope alpha=0.97. After this, the afterglow decay seems to flatten. Between 0.06 days and 0.95 days, the afterglow magnitude remains unchanged, indicating a plateau phase. As the afterglow has resumed its decay 0.1 days later, this probably implies that the afterglow underwent a strong rebrightening which we caught after the peak. This is reminiscent of GRB 071003, which lies at a very similar redshift (Perley et al. 2008, ApJ, submitted, arXiv:0805.2394) of ~ 1.6 (Jakobsson et al., GCN 7832).
Furthermore, we determined the R band magnitude at two epochs:
```
dt		R

0.01655957	19.87
0.95457023	20.75
```
Corrected for the moderate Galactic foreground extinction of E(B-V) = 0.136, we find R - I ~ 2 mag. This is a very red color for an afterglow, indicating strong internal reddening due to dust. We caution that the USNOB1.0 comparison star may have incorrect photometry, on the other hand, a simple image comparison shows that the R band magnitude is much fainter than the I band magnitude.
The strong rebrightening combined with the large correction for dust extinction that is needed imply that this is an intrinsically extremely luminous afterglow. Further follow-up, especially in the NIR bands, is highly encouraged.
This message may be cited.
GCN Circular #7851
C. Clemens, A. Kupcu Yoldas, J. Greiner, T. Kruehler, A. Yoldas (all MPE Garching) and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 080605 for a second time at 02:43 UT on June 7th, 2008 about 1.12 days after the GRB trigger with 25 mins of effective exposures in g'r'i'z'.
We still detect the bright afterglow within the refined 0.5'' Swift-UVOT error circle (Kuin et al., GCN #7844) to the following preliminary magnitudes of
```
r' = 22.3,
i' = 21.7 and
z' = 21.4
```
with typical errors of +/- 0.1. Given magnitudes are calibrated against USNO-B1 field stars and might be affected by the bright, nearby star.
This indicates a clear fading of the optical afterglow compared to our first epoch observations (C. Clemens et al., GCN #7834).
Please note, that no correction for the galactic foreground reddening of E(B-V) = 0.136 mag (Schlegel et al., 1998) has been applied.
GCN Circular #7854
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team report:
The bright GRB 080605 (Swift-BAT trigger #313299: Sbarufatti et al., GCN 7828, Cummings et al., GCN 7839) triggered Konus-Wind at T0=85682.336 s UT (23:48:02.336).
The burst light curve shows a multipeaked structure with a total duration of ~20s.
As observed by Konus-Wind the burst had a fluence of 3.02(-0.12, +0.13)x10^-5 erg/cm2, and a 16-ms peak flux measured from T0+7.984 s of (1.60 +/- 0.33)x10^-5 erg/cm2/s (both in the 20 keV - 2 MeV energy range).
The time-integrated spectrum of the burst (from T0 to T0+18.944 s) can be fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.03 +/- 0.07, and Ep = 252(-17, +20) keV (chi2 = 57.2/61 dof). Fitting by GRBM (Band) model yields: the low-energy photon index is alpha = -1.02 +/- 0.08, the high energy photon index beta < -2.75, the peak energy Ep = 246(-18, +23) keV (chi2 = 56.7/60 dof).
The spectrum of the most intense peak (from T0+7.168 s to T0+8.960 s) is well fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model with alpha = -0.94 +/- 0.10 and Ep = 333(-34, +42) keV (chi2 = 60.6/54 dof). Fitting by GRBM (Band) model yields: the low-energy photon index is alpha = -0.87(-0.12, +0.13), the high energy photon index beta = -2.58(-0.84, +0.31), the peak energy Ep = 297(-40, +46) keV (chi2 = 56.6/53 dof).
All the quoted errors are at the 90% confidence level.
Assuming z = 1.640 (Jakobsson et al., GCN 7832) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, Omega_\Lambda = 0.73, the isotropic energy release is E_iso ~2.1x10^53 erg, the maximum luminosity is (L_iso)_max ~3.0x10^53 erg/s, and Ep_rest ~660 keV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080605_T85682/
GCN Circular #7857
V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the optical afterglow of Swift GRB 080605 (Sbarufatti et al., GCN 7828) in second epoch on June 06 with Zeiss-1000 (Simeiz) telescope of CrAO observatory with favorable weather conditions and seeing about 2". Our first epoch astrometry of the source (Rumyantsev et al., GCN 7833) is in agreement with refined UVOT position of GRB080605 (Kuin et al., GCN 7844). The observation of the first epoch started 8 minute after burst onset (Rumyantsev et al., GCN 7833) was performed under descending weather conditions with seeing about 3". Improved photometry of the first epoch observation as well as observation on June 6 is based on USNO-B1.0 star RA (J2000) = 17 28 29.92, Dec.(J2000) = +04 00 36.5, assuming R=15.90, I=14.54:
```
T0+          Exposure,   Filter,  mag,
(d,mid time)

  0.006251 120    R  18.04 +/- 0.08
  0.007698 120    R  18.43 +/- 0.06
  0.009457 120    R  18.62 +/- 0.06
  0.010985 120    R  18.63 +/- 0.23
  0.015163 120    R  18.93 +/- 0.23
  0.018068 120    R >19.04
  0.019504 120    R  18.86 +/- 0.20
  0.026031 120    I  18.12 +/- 0.28
  0.033219 120    V >17.50
  0.034654 120    V >18.20
  0.904028 34x120 R  21.13 +/- 0.06
```
The photometry is still preliminary and not corrected for Galaxy extinction and might be affected by the bright, nearby star.
It is evident that the source is faded between June 5 and June 6. Power law index of early afterglow decay ~0.8 is compatible with index obtained in I-band (Kann et al., GCN 7845). However our absolute photometry in R-band have a significant offset in comparison with early observations by Kann et al. (GCN 7845) and compatible with photometry of Gomboc et al. (GCN 7831). Our early observation suggests R-I ~ 1.2, however we caution the color of the afterglow is also depending on photometry which is affected by bright, nearby star.
The message may be cited.
GCN Circular #7863
M. Yoshida, K. Yanagisawa, D. Kuroda, Y. Shimizu, S. Nagayama, H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We performed optical imaging observation (Rc, and Ic) of the field of GRB 080605 (Sbarufatti et al., GCN 7828) with 50cm MITSuME telescope at Okayama Astrophysical Observatory June 6 2008 UT. We detected a point source at the UVOT position of the optical afterglow (Kuin et al., GCN 7844). Differential photometry was made using a USNO B1.0 star, USNO-ID 0940-0289655 (Kann et al., GCN 7845). The Ic-band magnitude of the source was almost constant from T-T0 = 0.516 to 0.756. The source is about 1.5 magnitude fainter in Rc-band than in Ic-band. These results are consistent with other reports (Kann et al., GCN 7845, Rumyantsev et al., GCN 7857).
MITSuME observation start: 2008-06-06 11:35:11 UT
```
mid-UT        T-T0(days)   exp-T         Ic
(2008-06-06)
---------------------------------------------------
12:11:27      0.516314     60 min    19.03 +/- 0.38
12:48:05      0.541753     60 min    19.00 +/- 0.29
14:00:54      0.592315     60 min    18.85 +/- 0.18
15:15:44      0.644288     60 min    19.03 +/- 0.22
16:30:50      0.696429     60 min    18.82 +/- 0.21
17:56:24      0.755856     80 min    18.87 +/- 0.30
---------------------------------------------------

mid-UT
(2008-06-06)  T-T0(days)   ext-T          Rc
---------------------------------------------------
15:52:20      0.669745     120 min   20.58 +/- 0.32
---------------------------------------------------
```
GCN Circular #7864
D. A. Kann, U. Laux & S. Ertel (TLS Tautenburg) report:
We obtained further images of the Swift GRB 080605 (Sbarufatti et al., GCN 7828). A 300 second Ic frame obtained under excellent observing conditions shows the field remains unchanged in comparison to the second epoch as well as the final images of the first epoch (Kann et al., GCN 7845). Recently, Yoshida et al. (GCN 7863) also claimed detection of a plateau phase. Clemens et al. (GCN 7851), on the other hand, report a clear fading of the afterglow, as well as only a moderately red color in comparison to Kann et al. (GCN 7845), which can possibly be explained by the moderate Galactic reddening alone.
Comparison with a multicolor finding chart taken by GROND (C. Clemens, priv. comm.) reveals the culprit: source confusion. Near the position of the afterglow, there are in total three sources, all seemingly stellar in GROND images, along a line. The star to the southeast (Source #1) was immediately reported (Sbarufatti et al., GCN 7828, Kann et al., GCN 7829) and is clearly visible in the DSS. To the northwest, there is another source (Source #2), also clearly visible in the DSS. An inspection of the DSS IR frame reveals that #2 is hardly visible at all, but a new source (Source #3), inbetween #1 and #2, now becomes clearly visible. This source is extremely red, possibly a red dwarf, and it is THIS source which begins to dominate the photometry reported in Kann et al. (GCN 7845) (and presumably Yoshida et al., GCN 7863), which is mostly I band. The small offset from source #1 lead us to believe that this is the afterglow (and explained the puzzling observation that it seemed to slightly shift position).
Therefore, we retract the identification of a plateau phase of the afterglow of GRB 080605, as well as the claim of extreme redness and the resulting high lumonisity around 1 day in the observer frame. On the other hand, the afterglow IS clearly detected on the early I band frames of the TLS RRM observation, as well as in the R band and a stacked V band frame. The early photometry, which leads to a decay slope of alpha ~ 1, is still valid. Image subtraction will have to be performed to see how many detections we have actually gotten.
This message may be cited.
GCN Report 142.1
GCN_Report 142.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_142_1.pdf by B. Sbarufatti at INAF-IASF Pa titled: "Final Swift Observations of GRB 080605"
1203.1919 from 9 Mar 12
T. Kr�hler et al.: The metal-enriched host of an energetic gamma-ray burst at z ~ 1.6
(Abridged) Long gamma-ray burst (GRB) host galaxies might open a short-cut to the characteristics of typical star-forming galaxies throughout the history of the Universe. Due to the absence of near-infrared (NIR) spectroscopy, however, detailed investigations, specifically a determination of the gas-phase metallicity of gamma-ray burst hosts, was largely limited to redshifts z < 1 to date. Here, we report observations of the galaxy hosting GRB 080605 at z = 1.64. We avail of VLT/X-shooter optical/NIR spectroscopy to measure the metallicity, electron density, star-formation rate (SFR), and reddening of the host. Specifically, we use different strong-line diagnostics based on [N II] to robustly measure the gas-phase metallicity for the first time for a GRB host at this redshift. The host of the energetic (E_iso ~ 2 x 10^53 erg) GRB 080605 is a vigorously star-forming galaxy with an H\alpha-derived SFR of 34 M_sun/yr. Its ISM is significantly enriched with metals with an oxygen abundance between 8.3 and 8.7 depending on the adopted strong-line calibrator. This corresponds to values in the range of 0.4-1.1 times the solar value. For its measured stellar mass of 5 x 10^9 M_sun and SFR this value is fully consistent with the fundamental metallicity relation defined by star-forming field galaxies. Our observations directly illustrate that GRB hosts are not necessarily metal-poor, both on absolute scales as well as relative to their stellar mass and SFR. GRB hosts could thus be fair tracers of the population of ordinary star-forming galaxies as a whole at z > 1.
1205.0387 from 3 May 12
Tayyaba Zafar et al.: The properties of the 2175AA extinction feature discovered in GRB afterglows
Giorgos Leloudas (1), Pall Jakobsson (4), Christina C. Thone (5), Daniel A. Perley (6), Adam N. Morgan (6), Joshua Bloom (6), Jochen Greiner (3) ((1) DARK, (2) LAM, (3) MPI, (4) Univ. of Iceland (5) Univ. of California) The unequivocal, spectroscopic detection of the 2175 bump in extinction curves outside the Local Group is rare. To date, the properties of the bump have been examined in only two GRB afterglows (GRB 070802 and GRB 080607). In this work we analyse in detail the detections of the 2175 extinction bump in the optical spectra of the two further GRB afterglows: GRB 080605 and 080805. We gather all available optical/NIR photometric, spectroscopic and X-ray data to construct multi-epoch SEDs for both GRB afterglows. We fit the SEDs with the Fitzpatrick & Massa (1990) model with a single or broken PL. We also fit a sample of 38 GRB afterglows, known to prefer a SMC-type extinction curve, with the same model. We find that the SEDs of GRB 080605 and GRB 080805 at two epochs are fit well with a single PL with a derived extinction of A_V = 0.52(+0.13 -0.16) and 0.50 (+0.13 -0.10), and 2.1(+0.7-0.6) and 1.5+/-0.2 respectively. While the slope of the extinction curve of GRB 080805 is not well-constrained, the extinction curve of GRB 080605 has an unusual very steep far-UV rise together with the 2175 bump. Such an extinction curve has previously been found in only a small handful of sightlines in the MW. One possible explanation of such an extinction curve may be dust arising from two different regions with two separate grain populations, however we cannot distinguish the origin of the curve. We finally compare the four 2175 bump sightlines to the larger GRB afterglow sample and to Local Group sightlines. We find that while the width and central positions of the bumps are consistent with what is observed in the Local Group, the relative strength of the detected bump (A_bump) for GRB afterglows is weaker for a given A_V than for almost any Local Group sightline. Such dilution of the bump strength may offer tentative support to a dual dust-population scenario.

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