Gamma-ray Burst 150801B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 22:42:04 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     650977,   Seg_Num: 0
GRB_RA:           82.959d {+05h 31m 50s} (J2000),
                  83.150d {+05h 32m 36s} (current),
                  82.345d {+05h 29m 23s} (1950)
GRB_DEC:          -5.387d {-05d 23' 14"} (J2000),
                  -5.377d {-05d 22' 36"} (current),
                  -5.423d {-05d 25' 22"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       1205 [cnts]    Image_Peak=90 [image_cnts]
TRIGGER_DUR:     0.256 [sec] 
TRIGGER_INDEX:   120     E_range: 15-50 keV
BKG_INTEN:       25806 [cnts]
BKG_TIME:        81697.06 SOD {22:41:37.06} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17235 TJD;   213 DOY;   15/08/01
GRB_TIME:        81708.64 SOD {22:41:48.64} UT
GRB_PHI:         -140.54 [deg]
GRB_THETA:        33.37 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     13.00 [sigma]
IMAGE_SIGNIF:    7.70 [sigma]
MERIT_PARAMS:     +1  +0  +0  -2  +1  -2  +0  +0 -59  +0 
SUN_POSTN:       131.80d {+08h 47m 13s}  +17.91d {+17d 54' 31"}
SUN_DIST:         53.34 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.00d {+22h 04m 01s}   -8.88d {-08d 52' 31"}
MOON_DIST:       110.88 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.15 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       82.01,-28.63 [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 = 128.13,0.46 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 22:43:13 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 47s} (J2000)
POINT_DEC:        -5.393d {-05d 23' 34"} (J2000)
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  81787.39 SOD {22:43:07.39} UT,   78.8 [sec] since BAT Trigger Time
COUNTS:          3    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 22:45:43 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     650977,   Seg_Num: 0
GRB_RA:           82.959d {+05h 31m 50s} (J2000),
                  83.150d {+05h 32m 36s} (current),
                  82.345d {+05h 29m 23s} (1950)
GRB_DEC:          -5.387d {-05d 23' 14"} (J2000),
                  -5.377d {-05d 22' 36"} (current),
                  -5.423d {-05d 25' 22"} (1950)
GRB_DATE:        17235 TJD;   213 DOY;   15/08/01
GRB_TIME:        81708.64 SOD {22:41:48.64} UT
TRIGGER_INDEX:   120
GRB_PHI:         -140.54 [deg]
GRB_THETA:        33.37 [deg]
DELTA_TIME:      -37.00 [sec]
TRIGGER_DUR:     0.256 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     13.00 [sigma]
IMAGE_SIGNIF:    7.70 [sigma]
LC_URL:          sw00650977000msb.lc
SUN_POSTN:       131.81d {+08h 47m 13s}  +17.91d {+17d 54' 29"}
SUN_DIST:         53.34 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.04d {+22h 04m 09s}   -8.86d {-08d 51' 53"}
MOON_DIST:       110.84 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.15 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       82.01,-28.63 [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 = 128.13,0.46 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 22:46:50 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 47s} (J2000)
POINT_DEC:        -5.394d {-05d 23' 36"} (J2000)
POINT_ROLL:      62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  81792.50 SOD {22:43:12.50} UT,   83.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.051
N_STARS:         14
X_OFFSET:        584 [pixels]
Y_OFFSET:        487 [pixels]
X_MAX:           1543 [pixels]
Y_MAX:           1446 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00650977000msufc0083.fits
SUN_POSTN:       131.81d {+08h 47m 13s}  +17.91d {+17d 54' 28"}
SUN_DIST:         53.36 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.05d {+22h 04m 12s}   -8.86d {-08d 51' 41"}
MOON_DIST:       110.82 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 22:47:07 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     650977,   Seg_Num: 0
GRB_RA:           82.9657d {+05h 31m 51.76s} (J2000),
                  83.1572d {+05h 32m 37.73s} (current),
                  82.3513d {+05h 29m 24.31s} (1950)
GRB_DEC:          -5.3899d {-05d 23' 23.6"} (J2000),
                  -5.3794d {-05d 22' 45.9"} (current),
                  -5.4255d {-05d 25' 31.7"} (1950)
GRB_ERROR:       3.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  81801.00 SOD {22:43:21.00} UT,   92.4 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       131.81d {+08h 47m 13s}  +17.91d {+17d 54' 28"}
SUN_DIST:         53.34 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.05d {+22h 04m 13s}   -8.86d {-08d 51' 38"}
MOON_DIST:       110.84 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.14 [deg] galactic lon,lat of the burst
ECL_COORDS:       82.02,-28.63 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 22:47:22 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 47s} (J2000)
POINT_DEC:        -5.394d {-05d 23' 36"} (J2000)
POINT_ROLL:      62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  81792.50 SOD {22:43:12.50} UT,   83.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.051
N_STARS:         14
X_OFFSET:        584 [pixels]
Y_OFFSET:        487 [pixels]
X_MAX:           1543 [pixels]
Y_MAX:           1446 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00650977000msufc0083.fits
SUN_POSTN:       131.81d {+08h 47m 14s}  +17.91d {+17d 54' 28"}
SUN_DIST:         53.36 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.06d {+22h 04m 13s}   -8.86d {-08d 51' 36"}
MOON_DIST:       110.81 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [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:     Sat 01 Aug 15 22:48:30 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 47s} (J2000)
POINT_DEC:        -5.394d {-05d 23' 36"} (J2000)
ROLL:            62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  81792.50 SOD {22:43:12.50} UT,   83.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     460161807
X_OFFSET:        903 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1063
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00650977000msuni0098.fits
SUN_POSTN:       131.81d {+08h 47m 14s}  +17.91d {+17d 54' 27"}
SUN_DIST:         53.36 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.07d {+22h 04m 16s}   -8.86d {-08d 51' 24"}
MOON_DIST:       110.80 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [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:     Sat 01 Aug 15 22:48:42 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 47s} (J2000)
POINT_DEC:        -5.394d {-05d 23' 36"} (J2000)
ROLL:            62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  81792.50 SOD {22:43:12.50} UT,   83.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     460161807
X_OFFSET:        903 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1063
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00650977000msuni0098.fits
SUN_POSTN:       131.81d {+08h 47m 14s}  +17.91d {+17d 54' 27"}
SUN_DIST:         53.36 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.07d {+22h 04m 16s}   -8.86d {-08d 51' 22"}
MOON_DIST:       110.80 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 22:54:11 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 46s} (J2000)
POINT_DEC:        -5.396d {-05d 23' 46"} (J2000)
POINT_ROLL:      62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  82004.57 SOD {22:46:44.57} UT,   295.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.611
N_STARS:         43
X_OFFSET:        344 [pixels]
Y_OFFSET:        247 [pixels]
X_MAX:           1783 [pixels]
Y_MAX:           1686 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00650977000msufc0295.fits
SUN_POSTN:       131.81d {+08h 47m 15s}  +17.91d {+17d 54' 23"}
SUN_DIST:         53.37 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.12d {+22h 04m 30s}   -8.84d {-08d 50' 25"}
MOON_DIST:       110.75 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 22:54:20 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 46s} (J2000)
POINT_DEC:        -5.396d {-05d 23' 46"} (J2000)
POINT_ROLL:      62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  82004.57 SOD {22:46:44.57} UT,   295.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.611
N_STARS:         43
X_OFFSET:        344 [pixels]
Y_OFFSET:        247 [pixels]
X_MAX:           1783 [pixels]
Y_MAX:           1686 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00650977000msufc0295.fits
SUN_POSTN:       131.81d {+08h 47m 15s}  +17.91d {+17d 54' 23"}
SUN_DIST:         53.37 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.13d {+22h 04m 30s}   -8.84d {-08d 50' 23"}
MOON_DIST:       110.75 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [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:     Sat 01 Aug 15 22:55:02 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     650977,   Seg_Num: 0
GRB_RA:           82.9669d {+05h 31m 52.05s} (J2000),
                  83.1584d {+05h 32m 38.02s} (current),
                  82.3525d {+05h 29m 24.60s} (1950)
GRB_DEC:          -5.3884d {-05d 23' 18.2"} (J2000),
                  -5.3779d {-05d 22' 40.5"} (current),
                  -5.4240d {-05d 25' 26.2"} (1950)
GRB_ERROR:       2.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  81801.00 SOD {22:43:21.00} UT,   92.4 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       131.81d {+08h 47m 15s}  +17.91d {+17d 54' 23"}
SUN_DIST:         53.34 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.13d {+22h 04m 32s}   -8.84d {-08d 50' 16"}
MOON_DIST:       110.77 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.14 [deg] galactic lon,lat of the burst
ECL_COORDS:       82.02,-28.63 [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.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 22:55:37 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 46s} (J2000)
POINT_DEC:        -5.396d {-05d 23' 46"} (J2000)
ROLL:            62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  82004.57 SOD {22:46:44.57} UT,   295.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     460162019
X_OFFSET:        903 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1063
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00650977000msuni0310.fits
SUN_POSTN:       131.81d {+08h 47m 15s}  +17.91d {+17d 54' 22"}
SUN_DIST:         53.37 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.14d {+22h 04m 33s}   -8.84d {-08d 50' 10"}
MOON_DIST:       110.74 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [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:     Sat 01 Aug 15 22:55:47 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 46s} (J2000)
POINT_DEC:        -5.396d {-05d 23' 46"} (J2000)
ROLL:            62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  82004.57 SOD {22:46:44.57} UT,   295.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     460162019
X_OFFSET:        903 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1063
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00650977000msuni0310.fits
SUN_POSTN:       131.81d {+08h 47m 15s}  +17.91d {+17d 54' 22"}
SUN_DIST:         53.37 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.14d {+22h 04m 33s}   -8.84d {-08d 50' 08"}
MOON_DIST:       110.73 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [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_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #18104
B. Sbarufatti (INAF-OAB/PSU), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), L. M. Z. Hagen (PSU), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 22:41:48 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150801B (trigger=650977). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 82.959, -5.387 which is
```
   RA(J2000) = 05h 31m 50s
   Dec(J2000) = -05d 23' 14"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several overlapping peaks with a total duration of about 20 sec. The peak count rate was ~2600 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 22:43:07.3 UT, 78.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 82.9666, -5.3883 which is equivalent to:
```
   RA(J2000)  = 05h 31m 51.99s
   Dec(J2000) = -05d 23' 18.0"
```
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This location is 27 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 83 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.24.
We note that this event is in the vicinity of the Orion Nebula. However, it appears in all other respects to be a typical GRB.
Burst Advocate for this burst is B. Sbarufatti (boris.sbarufatti AT brera.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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 23:02:12 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 46s} (J2000)
POINT_DEC:        -5.396d {-05d 23' 46"} (J2000)
POINT_ROLL:      62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  82583.10 SOD {22:56:23.10} UT,   874.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.639
N_STARS:         79
X_OFFSET:        344 [pixels]
Y_OFFSET:        247 [pixels]
X_MAX:           1783 [pixels]
Y_MAX:           1686 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00650977000msufc0874.fits
SUN_POSTN:       131.82d {+08h 47m 16s}  +17.91d {+17d 54' 18"}
SUN_DIST:         53.37 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.20d {+22h 04m 49s}   -8.82d {-08d 49' 02"}
MOON_DIST:       110.67 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Aug 15 23:02:49 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 46s} (J2000)
POINT_DEC:        -5.396d {-05d 23' 46"} (J2000)
POINT_ROLL:      62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  82583.10 SOD {22:56:23.10} UT,   874.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.639
N_STARS:         79
X_OFFSET:        344 [pixels]
Y_OFFSET:        247 [pixels]
X_MAX:           1783 [pixels]
Y_MAX:           1686 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00650977000msufc0874.fits
SUN_POSTN:       131.82d {+08h 47m 16s}  +17.90d {+17d 54' 18"}
SUN_DIST:         53.37 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.21d {+22h 04m 50s}   -8.82d {-08d 48' 55"}
MOON_DIST:       110.67 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [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:     Sat 01 Aug 15 23:04:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 46s} (J2000)
POINT_DEC:        -5.396d {-05d 23' 46"} (J2000)
ROLL:            62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  82583.10 SOD {22:56:23.10} UT,   874.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     460162598
X_OFFSET:        903 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1063
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00650977000msuni0889.fits
SUN_POSTN:       131.82d {+08h 47m 16s}  +17.90d {+17d 54' 17"}
SUN_DIST:         53.37 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.23d {+22h 04m 55s}   -8.81d {-08d 48' 35"}
MOON_DIST:       110.65 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [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:     Sat 01 Aug 15 23:04:58 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     650977,   Seg_Num: 0
POINT_RA:         82.944d {+05h 31m 46s} (J2000)
POINT_DEC:        -5.396d {-05d 23' 46"} (J2000)
ROLL:            62.993d
IMG_START_DATE:  17235 TJD;   213 DOY;   15/08/01
IMG_START_TIME:  82583.10 SOD {22:56:23.10} UT,   874.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     460162598
X_OFFSET:        903 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1063
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00650977000msuni0889.fits
SUN_POSTN:       131.82d {+08h 47m 16s}  +17.90d {+17d 54' 16"}
SUN_DIST:         53.37 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      331.23d {+22h 04m 56s}   -8.81d {-08d 48' 33"}
MOON_DIST:       110.65 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      208.60,-20.16 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       81.99,-28.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #18108
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 1630 s of XRT Photon Counting mode data and 1 UVOT images for GRB 150801B, 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 = 82.96622, -5.38930 which is equivalent to:
```
RA (J2000): 05h 31m 51.89s
Dec (J2000): -05d 23' 21.5"
```
with an uncertainty of 1.7 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #18109
P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.A. Kennea (PSU), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), A. D'ai (INAF-IASFPA) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift-XRT team:
We have analysed 12 ks of XRT data for GRB 150801B (Sbarufatti et al. GCN Circ. 18104), from 64 s to 40.0 ks after the BAT trigger. We have analysed 12 ks of XRT data for GRB 150801B (Sbarufatti et al. GCN Circ. 18104), from 64 s to 40.0 ks after the BAT trigger. The data comprise 8 s in Windowed Timing (WT) mode while Swift was slewing to the burst, 270 s in PC mode, a further 185 s in WT mode during a bright flare starting at T0+366 s (also seen in the BAT), with the remainder 11.5 ks in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 18108).
The late-time light curve (from T0+4.9 ks) can be modelled with a power-law decay with a decay index of alpha=1.74 (+0.18, -0.17).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.79 (+0.21, -0.19). The best-fitting absorption column is 3.0 (+/-0.4) x 10^22 cm^-2, in excess of the Galactic value of 2.7 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 7.6 x 10^-11 (1.5 x 10^-10) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     3.0 (+/-0.4) x 10^22 cm^-2
Galactic foreground: 2.7 x 10^21 cm^-2
Excess significance: 10.8 sigma
Photon index:	     1.79 (+0.21, -0.19)
```
If the light curve continues to decay with a power-law decay index of 1.74, the count rate at T+24 hours will be 1.4 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x 10^-13 (2.2 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00650977.
This circular is an official product of the Swift-XRT team.
GCN Circular #18110
S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150801B (trigger #650977) (Sbarufatti, et al., GCN Circ. 18104). The BAT ground-calculated position is RA, Dec = 82.961, -5.374 deg which is
```
    RA(J2000)  =  05h 31m 50.7s
    Dec(J2000) = -05d 22' 28.0"
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 62%.
The mask-weighted light curve shows two widely separated episodes. The first episode was about 40 seconds long starting at about T-20 seconds. There were two prominent overlapping FRED peaks at T0 and T+10 seconds, followed by a return to background level. The second episode became detectable in BAT at about T+330 seconds and returned to background about T+450 seconds. There were two smaller cusp-shaped peaks at T+370 and T+390 seconds, about 10 and 7 seconds long. The peaks between 330 and 450 seconds are at the same time as bright X-ray flares detected by XRT. T90 (15-350 keV) was 426 +- 30 sec (estimated error including systematics).
The time-averaged spectrum from T-30.16 to T+433.94 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.84 +- 0.14. The fluence in the 15-150 keV band is 3.1 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+9.32 sec in the 15-150 keV band is 2.5 +- 0.2 ph/cm2/sec. 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/650977/BA/
GCN Circular #18111
L. M. Z. Hagen (PSU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150801B 84 s after the BAT trigger (Sbarufatti et al., GCN Circ. 18104). No optical afterglow consistent with the XRT position (Evans et al., GCN Circ. 18108) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC            83          233          147         >20.17
white              575        12513         1345         >21.35
v                  625        16812          901         >19.63
b                  551        11601         1264         >20.68
u_FC               295          545          245         >19.42
u                  699         7399          490         >19.53
uvw1              1105         7194          432         >19.41
uvw2              4943        13218          884         >19.89
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.24 in the direction of the burst (Schlegel et al. 1998).

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Jochen Greiner, last update: 03-Aug-2015 [Disclaimer]