Gamma-ray Burst 080413B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 08:51:30 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     309111,   Seg_Num: 0
GRB_RA:          326.134d {+21h 44m 32s} (J2000),
                 326.250d {+21h 44m 60s} (current),
                 325.437d {+21h 41m 45s} (1950)
GRB_DEC:         -19.969d {-19d 58' 08"} (J2000),
                 -19.931d {-19d 55' 51"} (current),
                 -20.200d {-20d 11' 57"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       12312 [cnts]    Image_Peak=1450 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       36740 [cnts]
BKG_TIME:        31861.28 SOD {08:51:01.28} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14569 TJD;   104 DOY;   08/04/13
GRB_TIME:        31872.54 SOD {08:51:12.54} UT
GRB_PHI:         -87.39 [deg]
GRB_THETA:        36.20 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     128.59 [sigma]
IMAGE_SIGNIF:    23.00 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2 +25  +0  +0 -46  +1 
SUN_POSTN:        22.03d {+01h 28m 08s}   +9.24d {+09d 14' 12"}
SUN_DIST:         62.16 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.07d {+08h 16m 18s}  +22.05d {+22d 03' 12"}
MOON_DIST:       159.21 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.08,-46.81 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      321.70, -6.03 [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 = 258.00,-13.57 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 08:53:34 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.121d {+21h 44m 29s} (J2000)
POINT_DEC:       -19.972d {-19d 58' 19"} (J2000)
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32003.79 SOD {08:53:23.79} UT,   131.2 [sec] since BAT Trigger Time
COUNTS:          23    Min_needed= 20
STD_DEV:         28.44   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      3
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        Standard deviation too large.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 08:54:42 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     309111,   Seg_Num: 0
GRB_RA:          326.134d {+21h 44m 32s} (J2000),
                 326.250d {+21h 44m 60s} (current),
                 325.437d {+21h 41m 45s} (1950)
GRB_DEC:         -19.969d {-19d 58' 08"} (J2000),
                 -19.931d {-19d 55' 51"} (current),
                 -20.200d {-20d 11' 57"} (1950)
GRB_DATE:        14569 TJD;   104 DOY;   08/04/13
GRB_TIME:        31872.54 SOD {08:51:12.54} UT
TRIGGER_INDEX:   148
GRB_PHI:         -87.39 [deg]
GRB_THETA:        36.20 [deg]
DELTA_TIME:      -5.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     128.59 [sigma]
IMAGE_SIGNIF:    23.00 [sigma]
LC_URL:          sw00309111000msb.lc
SUN_POSTN:        22.03d {+01h 28m 08s}   +9.24d {+09d 14' 15"}
SUN_DIST:         62.16 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.11d {+08h 16m 25s}  +22.04d {+22d 02' 39"}
MOON_DIST:       159.24 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.08,-46.81 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      321.70, -6.03 [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 = 258.00,-13.57 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 08:56:23 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.121d {+21h 44m 29s} (J2000)
POINT_DEC:       -19.972d {-19d 58' 18"} (J2000)
POINT_ROLL:      67.420d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32007.02 SOD {08:53:27.02} UT,   134.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.811
N_STARS:         33
X_OFFSET:        582 [pixels]
Y_OFFSET:        513 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1472 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00309111000msufc0134.fits
SUN_POSTN:        22.04d {+01h 28m 09s}   +9.24d {+09d 14' 17"}
SUN_DIST:         62.17 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.12d {+08h 16m 29s}  +22.04d {+22d 02' 22"}
MOON_DIST:       159.26 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.69, -6.03 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 08:56:52 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.121d {+21h 44m 29s} (J2000)
POINT_DEC:       -19.972d {-19d 58' 18"} (J2000)
POINT_ROLL:      67.420d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32007.02 SOD {08:53:27.02} UT,   134.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.811
N_STARS:         33
X_OFFSET:        582 [pixels]
Y_OFFSET:        513 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1472 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00309111000msufc0134.fits
SUN_POSTN:        22.04d {+01h 28m 09s}   +9.24d {+09d 14' 17"}
SUN_DIST:         62.17 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.13d {+08h 16m 30s}  +22.04d {+22d 02' 17"}
MOON_DIST:       159.27 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.69, -6.03 [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:     Sun 13 Apr 08 08:57:47 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.121d {+21h 44m 29s} (J2000)
POINT_DEC:       -19.972d {-19d 58' 18"} (J2000)
ROLL:            67.420d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32007.02 SOD {08:53:27.02} UT,   134.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     229769609
X_OFFSET:        901 [pixels]
Y_OFFSET:        832 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       992
BINNING_INDEX:   1
IM_URL:          sw00309111000msuni0134.fits
SUN_POSTN:        22.04d {+01h 28m 09s}   +9.24d {+09d 14' 18"}
SUN_DIST:         62.17 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.13d {+08h 16m 32s}  +22.04d {+22d 02' 07"}
MOON_DIST:       159.28 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.69, -6.03 [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:     Sun 13 Apr 08 08:58:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.121d {+21h 44m 29s} (J2000)
POINT_DEC:       -19.972d {-19d 58' 18"} (J2000)
ROLL:            67.420d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32007.02 SOD {08:53:27.02} UT,   134.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     229769609
X_OFFSET:        901 [pixels]
Y_OFFSET:        832 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       992
BINNING_INDEX:   1
IM_URL:          sw00309111000msuni0134.fits
SUN_POSTN:        22.04d {+01h 28m 09s}   +9.24d {+09d 14' 18"}
SUN_DIST:         62.17 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.14d {+08h 16m 33s}  +22.03d {+22d 02' 03"}
MOON_DIST:       159.28 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.69, -6.03 [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:     Sun 13 Apr 08 09:09:41 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.974d {-19d 58' 24"} (J2000)
POINT_ROLL:      67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32113.02 SOD {08:55:13.02} UT,   240.5 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        4.169
N_STARS:         57
X_OFFSET:        582 [pixels]
Y_OFFSET:        513 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1472 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00309111000msufc0240.fits
SUN_POSTN:        22.04d {+01h 28m 11s}   +9.24d {+09d 14' 29"}
SUN_DIST:         62.18 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.25d {+08h 16m 60s}  +22.00d {+22d 00' 05"}
MOON_DIST:       159.39 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 09:10:08 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.974d {-19d 58' 24"} (J2000)
POINT_ROLL:      67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32113.02 SOD {08:55:13.02} UT,   240.5 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        4.169
N_STARS:         57
X_OFFSET:        582 [pixels]
Y_OFFSET:        513 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1472 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00309111000msufc0240.fits
SUN_POSTN:        22.04d {+01h 28m 11s}   +9.24d {+09d 14' 29"}
SUN_DIST:         62.18 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.25d {+08h 17m 01s}  +22.00d {+22d 00' 01"}
MOON_DIST:       159.39 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [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:     Sun 13 Apr 08 09:11:12 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.974d {-19d 58' 24"} (J2000)
ROLL:            67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32113.02 SOD {08:55:13.02} UT,   240.5 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     229769715
X_OFFSET:        901 [pixels]
Y_OFFSET:        832 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       992
BINNING_INDEX:   1
IM_URL:          sw00309111000msuni0240.fits
SUN_POSTN:        22.05d {+01h 28m 11s}   +9.24d {+09d 14' 30"}
SUN_DIST:         62.18 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.26d {+08h 17m 03s}  +22.00d {+21d 59' 50"}
MOON_DIST:       159.40 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [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:     Sun 13 Apr 08 09:11:13 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     309111,   Seg_Num: 0
GRB_RA:          326.1444d {+21h 44m 34.65s} (J2000),
                 326.2598d {+21h 45m 02.35s} (current),
                 325.4466d {+21h 41m 47.18s} (1950)
GRB_DEC:         -19.9811d {-19d 58' 51.9"} (J2000),
                 -19.9428d {-19d 56' 34.0"} (current),
                 -20.2114d {-20d 12' 40.8"} (1950)
GRB_ERROR:       0.4 [arcsec radius, statistical only]
GRB_MAG:         16.50 +/- 0.50 [mag]
FILTER:          10, White
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32008.00 SOD {08:53:28.00} UT,   135.5 [sec] since BAT Trigger Time
SUN_POSTN:        22.05d {+01h 28m 11s}   +9.24d {+09d 14' 30"}
SUN_DIST:         62.16 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.26d {+08h 17m 03s}  +22.00d {+21d 59' 49"}
MOON_DIST:       159.38 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.83 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      321.70, -6.04 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 09:11:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.974d {-19d 58' 24"} (J2000)
ROLL:            67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32113.02 SOD {08:55:13.02} UT,   240.5 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     229769715
X_OFFSET:        901 [pixels]
Y_OFFSET:        832 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       992
BINNING_INDEX:   1
IM_URL:          sw00309111000msuni0240.fits
SUN_POSTN:        22.05d {+01h 28m 11s}   +9.24d {+09d 14' 31"}
SUN_DIST:         62.18 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.27d {+08h 17m 04s}  +22.00d {+21d 59' 45"}
MOON_DIST:       159.40 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [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:     Sun 13 Apr 08 09:12:36 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.973d {-19d 58' 23"} (J2000)
POINT_ROLL:      67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32749.11 SOD {09:05:49.11} UT,   876.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.931
N_STARS:         45
X_OFFSET:        582 [pixels]
Y_OFFSET:        513 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1472 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00309111000msufc0876.fits
SUN_POSTN:        22.05d {+01h 28m 11s}   +9.24d {+09d 14' 31"}
SUN_DIST:         62.19 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.28d {+08h 17m 07s}  +21.99d {+21d 59' 35"}
MOON_DIST:       159.41 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 09:12:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.973d {-19d 58' 23"} (J2000)
POINT_ROLL:      67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32749.11 SOD {09:05:49.11} UT,   876.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.931
N_STARS:         45
X_OFFSET:        582 [pixels]
Y_OFFSET:        513 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1472 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00309111000msufc0876.fits
SUN_POSTN:        22.05d {+01h 28m 11s}   +9.24d {+09d 14' 32"}
SUN_DIST:         62.19 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.28d {+08h 17m 08s}  +21.99d {+21d 59' 32"}
MOON_DIST:       159.42 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [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:     Sun 13 Apr 08 09:14:00 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.973d {-19d 58' 23"} (J2000)
ROLL:            67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32749.11 SOD {09:05:49.11} UT,   876.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     229770351
X_OFFSET:        901 [pixels]
Y_OFFSET:        832 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       992
BINNING_INDEX:   1
IM_URL:          sw00309111000msuni0876.fits
SUN_POSTN:        22.05d {+01h 28m 11s}   +9.24d {+09d 14' 33"}
SUN_DIST:         62.19 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.29d {+08h 17m 10s}  +21.99d {+21d 59' 21"}
MOON_DIST:       159.42 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [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:     Sun 13 Apr 08 09:14:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.973d {-19d 58' 23"} (J2000)
ROLL:            67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32749.11 SOD {09:05:49.11} UT,   876.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     229770351
X_OFFSET:        901 [pixels]
Y_OFFSET:        832 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       992
BINNING_INDEX:   1
IM_URL:          sw00309111000msuni0876.fits
SUN_POSTN:        22.05d {+01h 28m 11s}   +9.24d {+09d 14' 33"}
SUN_DIST:         62.19 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.30d {+08h 17m 11s}  +21.99d {+21d 59' 16"}
MOON_DIST:       159.43 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [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:     Sun 13 Apr 08 09:16:49 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.974d {-19d 58' 24"} (J2000)
POINT_ROLL:      67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32855.73 SOD {09:07:35.73} UT,   983.2 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        4.206
N_STARS:         58
X_OFFSET:        582 [pixels]
Y_OFFSET:        513 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1472 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00309111000msufc0983.fits
SUN_POSTN:        22.05d {+01h 28m 12s}   +9.24d {+09d 14' 35"}
SUN_DIST:         62.19 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.32d {+08h 17m 16s}  +21.98d {+21d 58' 52"}
MOON_DIST:       159.45 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 09:17:23 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.974d {-19d 58' 24"} (J2000)
POINT_ROLL:      67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32855.73 SOD {09:07:35.73} UT,   983.2 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        4.206
N_STARS:         58
X_OFFSET:        582 [pixels]
Y_OFFSET:        513 [pixels]
X_MAX:           1541 [pixels]
Y_MAX:           1472 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00309111000msufc0983.fits
SUN_POSTN:        22.05d {+01h 28m 12s}   +9.24d {+09d 14' 36"}
SUN_DIST:         62.19 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.32d {+08h 17m 18s}  +21.98d {+21d 58' 46"}
MOON_DIST:       159.46 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [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:     Sun 13 Apr 08 09:18:13 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.974d {-19d 58' 24"} (J2000)
ROLL:            67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32855.73 SOD {09:07:35.73} UT,   983.2 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     229770458
X_OFFSET:        901 [pixels]
Y_OFFSET:        832 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       992
BINNING_INDEX:   1
IM_URL:          sw00309111000msuni0983.fits
SUN_POSTN:        22.05d {+01h 28m 12s}   +9.24d {+09d 14' 36"}
SUN_DIST:         62.19 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.33d {+08h 17m 20s}  +21.98d {+21d 58' 37"}
MOON_DIST:       159.46 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [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:     Sun 13 Apr 08 09:18:14 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     309111,   Seg_Num: 0
GRB_RA:          326.1443d {+21h 44m 34.6s} (J2000),
                 326.2597d {+21h 45m 02.3s} (current),
                 325.4465d {+21h 41m 47.1s} (1950)
GRB_DEC:         -19.9810d {-19d 58' 51.6"} (J2000),
                 -19.9427d {-19d 56' 33.6"} (current),
                 -20.2113d {-20d 12' 40.5"} (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:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32387.00 SOD {08:59:47.00} UT,   514.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        22.05d {+01h 28m 12s}   +9.24d {+09d 14' 36"}
SUN_DIST:         62.17 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.33d {+08h 17m 20s}  +21.98d {+21d 58' 37"}
MOON_DIST:       159.44 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.83 [deg] galactic lon,lat of the burst
ECL_COORDS:      321.70, -6.04 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Apr 08 09:18:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     309111,   Seg_Num: 0
POINT_RA:        326.118d {+21h 44m 28s} (J2000)
POINT_DEC:       -19.974d {-19d 58' 24"} (J2000)
ROLL:            67.421d
IMG_START_DATE:  14569 TJD;   104 DOY;   08/04/13
IMG_START_TIME:  32855.73 SOD {09:07:35.73} UT,   983.2 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     229770458
X_OFFSET:        901 [pixels]
Y_OFFSET:        832 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1061
Y_GRB_POS:       992
BINNING_INDEX:   1
IM_URL:          sw00309111000msuni0983.fits
SUN_POSTN:        22.05d {+01h 28m 12s}   +9.24d {+09d 14' 37"}
SUN_DIST:         62.19 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      124.34d {+08h 17m 21s}  +21.98d {+21d 58' 33"}
MOON_DIST:       159.47 [deg]
MOON_ILLUM:      57 [%]
GAL_COORDS:       32.07,-46.80 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      321.68, -6.03 [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 Circular #7598
M. Stamatikos (NASA/ORAU), A. P. Beardmore (U Leicester), N. Gehrels (NASA/GSFC), S. D. Hunsberger (PSU), C. B. Markwardt (CRESST/GSFC/UMD), J. P. Osborne (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), R. L. C. Starling (U Leicester) and E. Troja (U Leicester/INAF-IASFPA) report on behalf of the Swift Team:
At 08:51:12 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080413B (trigger=309111). Swift started slewing approximately 70 seconds after the burst. The BAT on-board calculated location is RA, Dec 326.134, -19.969 which is
```
   RA(J2000) = 21h 44m 32s
   Dec(J2000) = -19d 58' 08"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peaked structure with a duration of about 3 sec. The peak count rate was ~15,000 counts/sec (15-350 keV), at ~0.2 sec after the trigger.
The XRT began observing the field at 08:53:23.8 UT, 131.2 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 326.14434, -19.98104 which is equivalent to:
```
   RA(J2000)  = 21h 44m 34.64s
   Dec(J2000) = -19d 58' 51.7"
```
with an uncertainty of 2.6 arcseconds (radius, 90% containment). This location is 55 arcseconds from the BAT onboard position, within the BAT error circle.
A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density, so we cannot provide limits on the redshift using spectroscopy and the relation from Grupe et al. (2007). A summary of the promptly downlinked data is given at http://www.swift.ac.uk/sper/309111/.
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 134 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	21:44:34.68 = 326.1445
  DEC(J2000) = -19:58:52.0  = -19.9811
```
with a 1-sigma error radius of about 0.6 arc sec. This position is 0.6 arc sec. from the XRT position. The estimated magnitude is 16.5 with a 1-sigma error of about 0.5 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04.
Burst Advocate for this burst is M. Stamatikos (michael AT milkyway.gsfc.nasa.gov). 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 #7599
T. Kruehler, J. Greiner, A. Kupcu Yoldas, C. Clemens, 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 080413B detected by Swift/BAT (trigger 309111, Stamatikos et al. 2008, GCN Circ. 7598) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile). Observations started at 08:56 UT on April 13th, 2008, 5 min after the burst.
We detect a new bright point source at
```
RA (J2000.0) = 21:44:34.67
DEC (J2000.0) = -19:58:52.4
```
with an uncertainty of 0.5", which is consistent with the UVOT position.
The object is detected in all seven bands, implying a redshift smaller than 3.5.
Preliminary photometry of the first 4 min exposure yields an J band magnitude of 16.5 calibrated against 2MASS field stars. The given magnitude is not corrected for the Galactic foreground reddening of E(B-V)=0.04 mag (Schlegel et al., 1998).
GCN Circular #7600
L.A. Antonelli, S. Covino, P. D'Avanzo, D. Fugazza, L. Calzoletti, S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F. D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C. Guidorzi, G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E. Meurs, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Stratta, G. Tagliaferri, G. Tosti, V.Testa, S.D. Vergani, F. Vitali report on behalf of the REM team:
The robotic 60-cm REM telescope located at La Silla (Chile) observed automatically the field of the GRB 080413B on April 13 08:52:43 UT (about 91 seconds after the burst).
The afterglow reported in GCN 7598, 7599 (Stamatikos et al., Kruehler et al.) is well detected in our early images at about H~14.3.
Further analyses and observations are in progress.
GCN Circular #7601
Paul M. Vreeswijk, Christina C. Thoene, Daniele Malesani, Johan P. U. Fynbo, Jens Hjorth (DARK/NBI), Pall Jakobsson (Univ. Hertfordshire), Nial R. Tanvir (Univ. Leicester), and Andrew J. Levan (Univ. Warwick), report on behalf of a larger collaboration:
We observed the afterglow of the possibly short GRB 080413B (Stamatikos et al., GCN 7598) with the ESO VLT equipped with FORS1. A 600 s spectrum centered on Apr 13.403 UT (49.5 min after the GRB) was acquired covering the range 3500-9000 AA.
From detection of numerous absorption features, including Fe II, Mg II and Mg I lines, we infer a redshift z = 1.10. In particular, we detect the Fe II 2396 fine-structure line, which confirms this redshift is very likely that of the host of the GRB.
We acknowledge excellent support from the VLT staff, particularly Thomas Szeifert, Jose Cortes, and Gianni Marconi.
GCN Circular #7606
S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-119 to T+148 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080413B (trigger #309111) (Stamatikos, et al., GCN Circ. 7598). The BAT ground-calculated position is RA, Dec = 326.138, -19.981 deg, which is
```
   RA(J2000)  =  21h 44m 33.1s 
   Dec(J2000) = -19d 58' 49.8" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 20%.
The mask-weighted light curve shows a single FRED-like peak starting at T-1.1 sec, peaking at T+0.2 sec, and returning to baseline at ~T+30 sec. T90 (15-350 keV) is 8.0 +- 1.0 sec (estimated error including systematics).
The time-averaged spectrum from T-1.3 to T+10.7 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.26 +- 0.27, and Epeak of 73.3 +- 15.8 keV (chi squared 32.60 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.2 +- 0.1 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T-0.26 sec in the 15-150 keV band is 18.7 +- 0.8 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.80 +- 0.06 (chi squared 45.07 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/309111/BA/
GCN Circular #7608
E. Troja (U. Leicester/INAF-IASFPa) and M. Stamatikos (NASA/ORAU) report on behalf of the Swift-XRT team:
We have analysed 9.9 ks of Swift XRT data for GRB 080413B (Stamatikos et al. GCN Circ. 7598), from T0+134 s to T0+20.1 ks. The data set consists of 376 s exposure in Windowed Timing (WT) mode followed by 9.5 ks exposure in Photon Counting (PC) mode.
By using orbits 2-4 of PC data [from T0+6.0 ks to T0+20.1 ks] in order to avoid pile-up effects, we derive an XRT refined position
```
     RA (2000) = 21h 44m 34.43s  = 326.1435 d
     Dec (2000) = -19d 58' 52.9" = -19.9814 d
```
with an uncertainty of 3.7 arcsec (90% containment). This position is 3.6 arcsec from the UVOT candidate afterglow (GCN Circ. 7598), and 3.4 arcsec from the source reported in Kruehler et al. (GCN Circ. 7599).
The X-ray light curve is well fitted by a simple power-law, with a decay slope of 0.88 +/- 0.06.
A spectrum obtained from the WT mode data, from T0+135 s to T0+511 s, can be modelled with an absorbed power-law with a photon index of 2.05 +/- 0.10 , and a redshifted absorbing column of (0.32 +/- 0.13) x 10^22 cm^-2 at a redshift of z=1.1 (Vreeswijk et al. GCN Circ 7601) in addition to the Galactic column of 3.06 x 10^20 cm^-2 (Kalberla et al. 2005). The observed (unabsorbed) 0.3-10 keV flux in this spectrum is 1.79 x 10^-10 (2.13 x 10^-10) erg/cm^2/s. The PC spectrum of the first four orbits, from T0+512 s to T0+20.1 ks, can be fit by an absorbed power-law model with photon index 1.93 +/- 0.08 and a column density consistent with the WT spectrum. All the reported errors are at the 90% confidence level.
If the source continues to decay at the present rate, we predict a count rate of 0.035 count/sec at T0+24 hours, which corresponds to a 0.3-10 keV observed (unabsorbed) flux of 1.6 x 10^-12 (1.8 x 10^-12) erg/cm^2/s.
This circular is an official product of the Swift-XRT team.
GCN Circular #7610
T. Sakamoto (GSFC/UMBC), T. Ukwatta (GWU), M. Stamatikos (GSFC/ORAU), S. D. Barthelmy (GSFC), N. Gehrels (GSFC),
We further report on additional spectral lag analysis regarding the possible short duration burst classification of GRB 080413B (Stamatikos et al. GCN Circ. 7598). We now believe GRB 080413B to be a long GRB based upon the following BAT prompt emission properties:
1) The spectral lag in 25-50 to 100-350 keV bands and 15-25 to 50-100 keV bands are 0.238 +- 0.016 sec and 0.136 +- 0.008 sec for 4 ms binning. Therefore, GRB 080413B shows a significant lag.
2) The T90 of the spike is 8.0 +- 1.0 sec based on the mask-weighted light curve (Barthelmy et al., GCN 7606), which is well within the long duration GRB population (Sakamoto et al. ApJS, 175, 179).
GCN Circular #7611
S. R. Oates and M. Stamatikos report on behalf of the Swift/UVOT team.
The Swift/UVOT began settled observations of the field of GRB 080413B 135= s after the BAT trigger (Stamatikos et al., GCN 7598). We detect the=20 afterglow in the 7 UVOT filters at the position:
```
RA(J2000.0)  =3D  21:44:34.65
DEC(J2000.0) =3D -19:58:52.40
```
with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence).=20 This position is consistent with the refined XRT position and the GROND optical position=20 (Kruehler et al., GCN 7599).
The magnitudes are reported below:
```
Filter    T_Mid(s)   Expo(s)               Magnitude
-------------------------------------------------------
White       184       98                 16.67 =B1 0.02
White       740       10                 17.67 =B1 0.15
v           440       393                17.64 =B1 0.10
v           1183      393                18.64 =B1 0.22
b           727       10                 18.82 =B1 0.71
u           796       19                 17.67 =B1 0.27
w1          682       19                 17.42 =B1 0.27
m2          810       19                 18.07 =B1 0.47
w2          762       19                 17.92 =B1 0.36
-------------------------------------------------------
```
The above magnitudes are not corrected for the Galactic extinction=20 corresponding to a reddening of E_{B-V} =3D 0.04 mag (Schlegel et al., 1998, ApJS, 500, 525)= .=20 The photometry is on the UVOT flight system described in Poole et al.=20 (2008,MNRAS,383,627).
GCN Circular #7612
L. Amati (INAF - IASF Bologna),
By assuming the VLT redshift of 1.10 (Vreeswijk et al., GCN 7601), the values of spectral parameters alpha and Ep, and the fluence, provided by Swift/BAT (Barthelmy et al., GCN 7606), a value of spectral parameter beta of -2.3 and a Lambda-CDM cosmology with H0=70 km/s/Mpc, Omega_M=0.27 and Omega_Lambda=0.73, the values of Ep,i and Eiso (1-10000 keV cosmological rest-frame) of GRB 080413B are approximately 150+/30 keV and (2.4+/-0.2)x10^52 erg, fully consistent with the Ep,i-Eiso correlation.
Given that this correlation holds for long GRBs only (see, e.g., Amati, MNRAS, 2006; Amati, astroph/0611189), this is a further evidence that GRB 080412B is not a short GRB.
This message may be cited.
GCN Circular #7615
A. Cucchiara and D. B. Fox (Penn State) with S. B. Cenko (Caltech), report on behalf of a larger collaboration:
"Starting on 2008 April 13.41 UT we observed GRB 080413B (Stamatikos et al. GCN 7598) with the GMOS spectrograph on the Gemini South telescope. We obtained a single 900-sec spectrum in the wavelength range 3900-6700A. The resolution of our spectrum is 5 Ang/pixel (R ~ 1100 at 5900A). We clearly observe several metal absorption features corresponding to the MgII doublet (2796,2803 A), MgI (2853A), FeII (2586A and 2600A), and FeI (3021A). These identifications are consistent with a host galaxy redshift of z = 1.10, confirming the result reported from VLT observations by Vreeswijk et al.(GCN 7601)."
GCN Circular #7617
Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward GRB 080413B (GCN 7598) at a frequency of 8.46 GHz at 2008 April 14.59 UT. We do not detect the GRB afterglow at the GROUND optical position (GCN 7599). The flux density at the GRB afterglow position is 86 =B1 36 uJy.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."
GCN Circular #7623
T. Enoto (Univ. of Tokyo), Y.E. Nakagawa, T. Tamagawa (RIKEN), T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira, Y. Hanabata (Hiroshima U.), K. Yamaoka, S. Sugita (Aoyama Gakuin U.), M. Tashiro, Y. Terada, Y. Urata, A. Endo, K. Onda, N. Kodaka, K. Morigami (Saitama U.), K. Nakazawa, K. Makishima (Univ. of Tokyo), E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara (Univ. of Miyazaki), M. Ohno, M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report:
The Swift GRB 080413B (Swift/BAT trigger #309111 ; Stamatikos et al., GCN 7598) was detected by the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 8:51:11.645 UT (=T0). The observed light curve shows a single peak starting at T0-0s, with a duration (T90) of about 2 seconds. The fluence in 150 - 1000 keV was (1.4 +/- 0.3) x 10^-6 erg/cm^2. The 1-s peak flux measured from T0+1s was 3.4 +/- 0.2 photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-1s to T0+8s is fitted by a single power-law with a photon index of 3.02 (+0.36, -0.32) (chi^2/d.o.f = 16.7/16) in 150 - 1000 keV. All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included.
The light curves with 1-sec time resolution for this burst are now available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html
GCN Circular #7626
A. Gomboc (Ljubljana), C. Guidorzi (U. Bicocca/INAF-OAB), A. Melandri, I.A. Steele, C.G. Mundell, D.F. Bersier, M.F. Bode, M.J. Burgdorf, S.N. Fraser, S. Kobayashi, C.J. Mottram, R.J. Smith (Liverpool JMU), P. O'Brien, N. Bannister, N. Tanvir (U. Leicester) report on behalf of larger GRB collaboration:
The 2-m Faulkes Telescope South observed the field of GRB 080413B (trigger=309111, Stamatikos et al. GCN 7598) starting 8.7-hr after the trigger time. We detect the optical afterglow (Stamatikos et al. GCN 7598, Kruehler et al. GCN 7599, Antonelli et al. GCN 7600) and measure the following magnitudes:
```
Filter   T_mid(hr)    Exposure(s)       Mag
----------------------------------------------------------------------
R          8.74          30          19.00 +/- 0.15
I          8.90         640          18.91 +/- 0.05
I          9.20        1080          19.15 +/- 0.05
I          9.54        1080          19.22 +/- 0.06
----------------------------------------------------------------------
```
Magnitudes were calibrated with respect to USNOB1 R2 and I.
GCN Circular #7629
T. Brennan, D. Reichart, M. Nysewander, A. LaCluyze, K. Ivarsen, J. A. Crain, M. Schubel, A. Foster, J. Haislip, J. Styblova, and A. Trotter report:
Skynet observed the localization of GRB 080413B (Stamatikos et al., GCN 7598) with four of the 16" PROMPT telescopes at CTIO beginning 27 seconds after the trigger (10 seconds after notification) in UBVRz'
We detect the afterglow (Stamatikos et al., GCN 7598) in BVRz'. At 42 seconds after the burst we measure B ~ 15.7 mag (calibrated to 2 USNO B1 stars), at 55 seconds we measure V ~ 15.4 mag (calibrated to 2 USNO B1 stars), and at 87 seconds we measure R ~ 15.4 mag (calibrated to 2 NOMAD stars).
1301.6204 from 29 Jan 13
J. Cant� et al.: Shock Dynamics In Relativistic Jets
We present a formalism of the dynamics of internal shocks in relativistic jets where the source has a time-dependent injection velocity and mass-loss rate. The variation of the injection velocity produces a two-shock wave structure, the working surface, that moves along the jet. This new formalism takes into account the fact that momentum conservation is not valid for relativistic flows where the relativistic mass lost by radiation must be taken into account, in contrast to the classic regime. We find analytic solutions for the working surface velocity and radiated energy for the particular case of a step function variability of the injection parameters. We model two cases: a pulse of fast material and a pulse of slow material (with respect to the mean flow). Applying these models to gamma ray burst light curves, one can determine the ratio of the Lorentz factors gamma_2 / gamma_1 and the ratio of the mass-loss rates dot{m_2} / dot{m_1} of the upstream and downstream flows. As an example, we apply this model to the sources GRB 080413B and GRB 070318 and find the values of these ratios. Assuming a Lorentz factor gamma_1=100, we further estimate jet mass-loss rates between dot{m_1} ~ 10^{-5}-1 Msun.yr^{-1}. We also calculate the fraction of the injected mass lost by radiation. For GRB 070318 this fraction is ~7%. In contrast, for GRB 080413B this fraction is larger than 50%; in this case radiation losses clearly affect the dynamics of the internal shocks.
1605.01334 from 5 May 16
J. J. Geng et al.: Imprints of Electron-positron Winds on the Multi-wavelength Afterglows of Gamma-ray Bursts
Optical re-brightenings in the afterglows of some gamma-ray bursts (GRBs) are unexpected within the framework of the simple external shock model. While it has been suggested that the central engines of some GRBs are newly born magnetars, we aim to relate the behaviors of magnetars to the optical re-brightenings. A newly born magnetar will lose its rotational energy in the form of Poynting-flux, which may be converted into a wind of electron-positron pairs through some magnetic dissipation processes. As proposed by Dai (2004), this wind will catch up with the GRB outflow and a long-lasting reverse shock would form. By applying this scenario to GRB afterglows, we find that the reverse shock propagating back into the electron-positron wind can lead to an observable optical re-brightening and a simultaneous X-ray plateau (or X-ray shallow decay). In our study, we select four GRBs, i.e., GRB 080413B, GRB 090426, GRB 091029, and GRB 100814A, of which the optical afterglows are well observed and show clear re-brightenings. We find that they can be well interpreted. In our scenario, the spin-down timescale of the magnetar should be slightly smaller than the peak time of the re-brightening, which can provide a clue to the characteristics of the magnetar.

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Jochen Greiner, last update: 05-May-2016 [Disclaimer]