Gamma-ray Burst 150724A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Jul 15 05:48:43 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     650141,   Seg_Num: 0
GRB_RA:           97.540d {+06h 30m 09s} (J2000),
                  97.709d {+06h 30m 50s} (current),
                  96.995d {+06h 27m 59s} (1950)
GRB_DEC:         -19.154d {-19d 09' 12"} (J2000),
                 -19.165d {-19d 09' 53"} (current),
                 -19.118d {-19d 07' 05"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       6939 [cnts]    Image_Peak=192 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   473     E_range: 25-100 keV
BKG_INTEN:       71037 [cnts]
BKG_TIME:        20761.10 SOD {05:46:01.10} UT
BKG_DUR:         24 [sec]
GRB_DATE:        17227 TJD;   205 DOY;   15/07/24
GRB_TIME:        20795.98 SOD {05:46:35.98} UT
GRB_PHI:         -139.72 [deg]
GRB_THETA:        37.47 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.64 [sigma]
IMAGE_SIGNIF:    7.19 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +2  -3  +0  +0 -68  +0 
SUN_POSTN:       123.27d {+08h 13m 04s}  +19.92d {+19d 55' 24"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.48d {+14h 01m 55s}   -9.74d {-09d 44' 21"}
MOON_DIST:       107.75 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.93,-13.15 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       99.65,-42.34 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
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 = 75.24,6.35 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Jul 15 05:49:41 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     650141,   Seg_Num: 0
GRB_RA:           97.5606d {+06h 30m 14.54s} (J2000),
                  97.7301d {+06h 30m 55.22s} (current),
                  97.0160d {+06h 28m 03.83s} (1950)
GRB_DEC:         -19.1657d {-19d 09' 56.5"} (J2000),
                 -19.1772d {-19d 10' 38.0"} (current),
                 -19.1304d {-19d 07' 49.3"} (1950)
GRB_ERROR:       5.4 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.27e-09 [erg/cm2/sec]
GRB_SIGNIF:      7.28 [sigma]
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  20898.60 SOD {05:48:18.60} UT,   102.6 [sec] since BAT Trigger Time
TAM[0-3]:        327.69 237.22 261.56 243.37
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       123.27d {+08h 13m 05s}  +19.92d {+19d 55' 23"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.49d {+14h 01m 57s}   -9.74d {-09d 44' 29"}
MOON_DIST:       107.73 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.95,-13.14 [deg] galactic lon,lat of the burst
ECL_COORDS:       99.68,-42.35 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.40 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Jul 15 05:49:50 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     650141,   Seg_Num: 0
GRB_RA:           97.5606d {+06h 30m 14.5s} (J2000),
                  97.7301d {+06h 30m 55.2s} (current),
                  97.0160d {+06h 28m 03.8s} (1950)
GRB_DEC:         -19.1657d {-19d 09' 56.5"} (J2000),
                 -19.1772d {-19d 10' 38.0"} (current),
                 -19.1304d {-19d 07' 49.3"} (1950)
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       53 [cnts]
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  20898.60 SOD {05:48:18.60} UT,   102.6 [sec] since BAT Trigger Time
CENTROID_X:      297.48,  raw= 297  [pixels]
CENTROID_Y:      275.94,  raw= 276  [pixels]
ROLL:            34.26 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -51.52
GRB_POS_XRT_Z:   -18.42
IMAGE_URL:       sw00650141000msxps_rw.img
SUN_POSTN:       123.27d {+08h 13m 05s}  +19.92d {+19d 55' 23"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.49d {+14h 01m 57s}   -9.74d {-09d 44' 30"}
MOON_DIST:       107.73 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.95,-13.14 [deg] galactic lon,lat of the burst
ECL_COORDS:       99.68,-42.35 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Jul 15 05:50:03 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     650141,   Seg_Num: 0
GRB_RA:           97.5606d {+06h 30m 14.5s} (J2000),
                  97.7301d {+06h 30m 55.2s} (current),
                  97.0160d {+06h 28m 03.8s} (1950)
GRB_DEC:         -19.1657d {-19d 09' 56.5"} (J2000),
                 -19.1772d {-19d 10' 38.0"} (current),
                 -19.1304d {-19d 07' 49.3"} (1950)
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       53 [cnts]
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  20898.60 SOD {05:48:18.60} UT,   102.6 [sec] since BAT Trigger Time
CENTROID_X:      297.48,  raw= 297  [pixels]
CENTROID_Y:      275.94,  raw= 276  [pixels]
ROLL:            34.26 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -51.52
GRB_POS_XRT_Z:   -18.42
IMAGE_URL:       sw00650141000msxps_rw.img
SUN_POSTN:       123.27d {+08h 13m 05s}  +19.92d {+19d 55' 23"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.49d {+14h 01m 58s}   -9.74d {-09d 44' 32"}
MOON_DIST:       107.73 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.95,-13.14 [deg] galactic lon,lat of the burst
ECL_COORDS:       99.68,-42.35 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Jul 15 05:50:37 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     650141,   Seg_Num: 0
GRB_RA:           97.540d {+06h 30m 09s} (J2000),
                  97.709d {+06h 30m 50s} (current),
                  96.995d {+06h 27m 59s} (1950)
GRB_DEC:         -19.154d {-19d 09' 12"} (J2000),
                 -19.165d {-19d 09' 53"} (current),
                 -19.118d {-19d 07' 05"} (1950)
GRB_DATE:        17227 TJD;   205 DOY;   15/07/24
GRB_TIME:        20795.98 SOD {05:46:35.98} UT
TRIGGER_INDEX:   473
GRB_PHI:         -139.72 [deg]
GRB_THETA:        37.47 [deg]
DELTA_TIME:      32.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.64 [sigma]
IMAGE_SIGNIF:    7.19 [sigma]
LC_URL:          sw00650141000msb.lc
SUN_POSTN:       123.27d {+08h 13m 05s}  +19.92d {+19d 55' 23"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.50d {+14h 01m 59s}   -9.74d {-09d 44' 37"}
MOON_DIST:       107.76 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.93,-13.15 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       99.65,-42.34 [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 = 75.24,6.35 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Jul 15 05:53:04 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     650141,   Seg_Num: 0
POINT_RA:         97.545d {+06h 30m 11s} (J2000)
POINT_DEC:       -19.161d {-19d 09' 39"} (J2000)
POINT_ROLL:      34.259d
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  20904.40 SOD {05:48:24.40} UT,   108.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.192
N_STARS:         190
X_OFFSET:        232 [pixels]
Y_OFFSET:        232 [pixels]
X_MAX:           1671 [pixels]
Y_MAX:           1671 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00650141000msufc0108.fits
SUN_POSTN:       123.27d {+08h 13m 05s}  +19.92d {+19d 55' 22"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.52d {+14h 02m 04s}   -9.75d {-09d 44' 57"}
MOON_DIST:       107.77 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.94,-13.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       99.66,-42.35 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Jul 15 05:53:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     650141,   Seg_Num: 0
POINT_RA:         97.545d {+06h 30m 11s} (J2000)
POINT_DEC:       -19.161d {-19d 09' 39"} (J2000)
POINT_ROLL:      34.259d
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  20904.40 SOD {05:48:24.40} UT,   108.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.192
N_STARS:         190
X_OFFSET:        232 [pixels]
Y_OFFSET:        232 [pixels]
X_MAX:           1671 [pixels]
Y_MAX:           1671 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00650141000msufc0108.fits
SUN_POSTN:       123.27d {+08h 13m 05s}  +19.92d {+19d 55' 21"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.52d {+14h 02m 05s}   -9.75d {-09d 45' 02"}
MOON_DIST:       107.77 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.94,-13.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       99.66,-42.35 [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 24 Jul 15 05:54:25 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     650141,   Seg_Num: 0
POINT_RA:         97.545d {+06h 30m 11s} (J2000)
POINT_DEC:       -19.161d {-19d 09' 39"} (J2000)
ROLL:            34.259d
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  20904.40 SOD {05:48:24.40} UT,   108.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     459409719
X_OFFSET:        879 [pixels]
Y_OFFSET:        933 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       1093
BINNING_INDEX:   1
IM_URL:          sw00650141000msuni0123.fits
SUN_POSTN:       123.27d {+08h 13m 05s}  +19.92d {+19d 55' 21"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.53d {+14h 02m 06s}   -9.75d {-09d 45' 08"}
MOON_DIST:       107.78 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.94,-13.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       99.66,-42.35 [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 24 Jul 15 05:54:38 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     650141,   Seg_Num: 0
POINT_RA:         97.545d {+06h 30m 11s} (J2000)
POINT_DEC:       -19.161d {-19d 09' 39"} (J2000)
ROLL:            34.259d
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  20904.40 SOD {05:48:24.40} UT,   108.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     459409719
X_OFFSET:        879 [pixels]
Y_OFFSET:        933 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       1093
BINNING_INDEX:   1
IM_URL:          sw00650141000msuni0123.fits
SUN_POSTN:       123.27d {+08h 13m 05s}  +19.92d {+19d 55' 21"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.53d {+14h 02m 07s}   -9.75d {-09d 45' 09"}
MOON_DIST:       107.78 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.94,-13.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       99.66,-42.35 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #18050
J. L. Racusin (NASA/GSFC), A. P. Beardmore (U Leicester), J. R. Cummings (NASA/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 05:46:35 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150724A (trigger=650141). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 97.540, -19.154 which is
```
   RA(J2000) = 06h 30m 09s
   Dec(J2000) = -19d 09' 12"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed multiple peaks structure with a duration of about 40 sec. The peak count rate was ~1412 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 05:48:18.6 UT, 102.6 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 97.56060, -19.16395 which is equivalent to:
```
   RA(J2000)  = 06h 30m 14.54s
   Dec(J2000) = -19d 09' 50.2"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 78 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 gives a column density consistent with the Galactic value of 2.94 x 10^21 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 1.27e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 250 seconds with the U filter starting 108 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 19.2 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 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.27.
Burst Advocate for this burst is J. L. Racusin (judith.racusin AT 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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Jul 15 06:05:48 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     650141,   Seg_Num: 0
POINT_RA:         97.546d {+06h 30m 11s} (J2000)
POINT_DEC:       -19.164d {-19d 09' 49"} (J2000)
POINT_ROLL:      34.257d
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  21660.36 SOD {06:01:00.36} UT,   864.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.228
N_STARS:         190
X_OFFSET:        319 [pixels]
Y_OFFSET:        373 [pixels]
X_MAX:           1758 [pixels]
Y_MAX:           1812 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00650141000msufc0864.fits
SUN_POSTN:       123.28d {+08h 13m 07s}  +19.92d {+19d 55' 15"}
SUN_DIST:         46.44 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.62d {+14h 02m 29s}   -9.78d {-09d 46' 40"}
MOON_DIST:       107.85 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.95,-13.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       99.66,-42.35 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 24 Jul 15 06:06:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     650141,   Seg_Num: 0
POINT_RA:         97.546d {+06h 30m 11s} (J2000)
POINT_DEC:       -19.164d {-19d 09' 49"} (J2000)
POINT_ROLL:      34.257d
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  21660.36 SOD {06:01:00.36} UT,   864.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.228
N_STARS:         190
X_OFFSET:        319 [pixels]
Y_OFFSET:        373 [pixels]
X_MAX:           1758 [pixels]
Y_MAX:           1812 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00650141000msufc0864.fits
SUN_POSTN:       123.28d {+08h 13m 07s}  +19.92d {+19d 55' 15"}
SUN_DIST:         46.44 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.62d {+14h 02m 29s}   -9.78d {-09d 46' 42"}
MOON_DIST:       107.85 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.95,-13.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       99.66,-42.35 [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 24 Jul 15 06:06:34 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     650141,   Seg_Num: 0
GRB_RA:           97.5597d {+06h 30m 14.32s} (J2000),
                  97.7292d {+06h 30m 55.00s} (current),
                  97.0151d {+06h 28m 03.61s} (1950)
GRB_DEC:         -19.1644d {-19d 09' 51.8"} (J2000),
                 -19.1759d {-19d 10' 33.3"} (current),
                 -19.1291d {-19d 07' 44.7"} (1950)
GRB_ERROR:       2.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  21256.00 SOD {05:54:16.00} UT,   460.0 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       123.28d {+08h 13m 07s}  +19.92d {+19d 55' 15"}
SUN_DIST:         46.43 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.63d {+14h 02m 30s}   -9.78d {-09d 46' 46"}
MOON_DIST:       107.84 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.95,-13.14 [deg] galactic lon,lat of the burst
ECL_COORDS:       99.68,-42.35 [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:     Fri 24 Jul 15 06:07:13 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     650141,   Seg_Num: 0
POINT_RA:         97.546d {+06h 30m 11s} (J2000)
POINT_DEC:       -19.164d {-19d 09' 49"} (J2000)
ROLL:            34.257d
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  21660.36 SOD {06:01:00.36} UT,   864.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     459410475
X_OFFSET:        878 [pixels]
Y_OFFSET:        932 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1038
Y_GRB_POS:       1092
BINNING_INDEX:   1
IM_URL:          sw00650141000msuni0879.fits
SUN_POSTN:       123.28d {+08h 13m 07s}  +19.92d {+19d 55' 14"}
SUN_DIST:         46.44 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.63d {+14h 02m 32s}   -9.78d {-09d 46' 51"}
MOON_DIST:       107.86 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.95,-13.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       99.66,-42.35 [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 24 Jul 15 06:07:22 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     650141,   Seg_Num: 0
POINT_RA:         97.546d {+06h 30m 11s} (J2000)
POINT_DEC:       -19.164d {-19d 09' 49"} (J2000)
ROLL:            34.257d
IMG_START_DATE:  17227 TJD;   205 DOY;   15/07/24
IMG_START_TIME:  21660.36 SOD {06:01:00.36} UT,   864.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     459410475
X_OFFSET:        878 [pixels]
Y_OFFSET:        932 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1038
Y_GRB_POS:       1092
BINNING_INDEX:   1
IM_URL:          sw00650141000msuni0879.fits
SUN_POSTN:       123.28d {+08h 13m 07s}  +19.92d {+19d 55' 14"}
SUN_DIST:         46.44 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      210.63d {+14h 02m 32s}   -9.78d {-09d 46' 53"}
MOON_DIST:       107.86 [deg]
MOON_ILLUM:      51 [%]
GAL_COORDS:      227.95,-13.15 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       99.66,-42.35 [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 #18052
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 150724A, we find an enhanced XRT position of the afterglow: RA, Dec: 97.5600, -19.1646 which is equivalent to:
```
   RA (J2000)  = 06 30 14.41
   Dec (J2000) = -19 09 52.5
```
with an uncertainty of 2.0 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/650141.
Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular #18054
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 2472 s of XRT Photon Counting mode data and 4 UVOT images for GRB 150724A, 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 = 97.56044, -19.16479 which is equivalent to:
```
RA (J2000): 06h 30m 14.51s
Dec (J2000): -19d 09' 53.3"
```
with an uncertainty of 1.9 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 #18055
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), J. L. Racusin (NASA/GSFC), 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+902 sec from recent telemetry downlinks, we report further analysis of BAT GRB 150724A (trigger #650141) (Racusin, et al., GCN Circ. 18050). The BAT ground-calculated position is RA, Dec = 97.549, -19.147 deg, which is
```
   RA(J2000)  =  06h 30m 11.7s 
   Dec(J2000) = -19d 08' 48.1" 
```
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 48%.
The mask-weighted light curve has at least 4 peaks starting at ~T-10 sec, with peaks at ~T+1 sec, ~T+24 sec, ~T+160 sec, & ~T+220 sec, and the emission ending at ~T+300 sec. T90 (15-350 keV) is 280 +- 44 sec (estimated error including systematics).
The time-averaged spectrum from T-1.07 to T+325.42 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.06 +- 0.15. The fluence in the 15-150 keV band is 2.2 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+24.08 sec in the 15-150 keV band is 0.9 +- 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/650141/BA/
GCN Circular #18057
M. De Pasquale (UCL-MSSL) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150724A 108 s after the BAT trigger (Racusin et al., GCN Circ. 18050). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 18054) 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 summed exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

u_FC               108          358          246         >19.7

v                  415         6930          510         >19.2
b                  364        12898         1165         >20.6
u                  108        12238         1769         >20.7
w1                 464        11324         1387         >20.5
m2                 439         7135          502         >19.9
w2                 390         6726          529         >20.2
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.27 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #18059
T.G.R. Roegiers (PSU), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU) and J.L. Racusin report on behalf of the Swift-XRT team:
We have analysed 11 ks of XRT data for GRB 150724A (Racusin et al. GCN Circ. 18050), from 91 s to 24.4 ks after the BAT trigger. The data comprise 349 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 18052). The late-time light curve (from T0+4.7 ks) is consistent with a constant source of mean count rate 2.2e+00 ct/sec. A power-law fit gives an index of -0.02 (+0.19, -0.20).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.70 (+/-0.04). The best-fitting absorption column is 3.70 (+0.21, -0.20) x 10^21 cm^-2, in excess of the Galactic value of 2.9 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.13 (+0.18, -0.17) and a best-fitting absorption column of 3.6 (+0.8, -0.7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (5.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     3.6 (+0.8, -0.7) x 10^21 cm^-2
Galactic foreground: 2.9 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     2.13 (+0.18, -0.17)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00650141.
This circular is an official product of the Swift-XRT team.
GCN Circular #18060
K.L. Page, A.P. Beardmore (U. Leicester) and J.L. Racusin (NASA/GSFC) report on behalf of the Swift-XRT team:
The description of the XRT light curve given in GCN Circ. 18059 was incorrect. Following significant flaring activity during the first 1.3 ks of data, the light curve from T0+4.7 ks to 24.0 ks remains approximately constant with a mean count rate of 0.04 ct/sec (not 2.2 ct/sec as previously stated). We apologise for any confusion.
This circular is an official product of the Swift-XRT team.

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Jochen Greiner, last update: 24-Jul-2015 [Disclaimer]