Gamma-ray Burst 180715A

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 15 Jul 18 18:07:24 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     848048,   Seg_Num: 0
GRB_RA:          235.069d {+15h 40m 17s} (J2000),
                 235.308d {+15h 41m 14s} (current),
                 234.425d {+15h 37m 42s} (1950)
GRB_DEC:          -0.925d {-00d 55' 28"} (J2000),
                  -0.984d {-00d 59' 00"} (current),
                  -0.764d {-00d 45' 49"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2833 [cnts]    Image_Peak=147 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   207     E_range: 50-350 keV
BKG_INTEN:       20846 [cnts]
BKG_TIME:        65210.73 SOD {18:06:50.73} UT
BKG_DUR:         8 [sec]
GRB_DATE:        18314 TJD;   196 DOY;   18/07/15
GRB_TIME:        65225.00 SOD {18:07:05.00} UT
GRB_PHI:         170.88 [deg]
GRB_THETA:        24.73 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     39.19 [sigma]
IMAGE_SIGNIF:    7.60 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +3  -2  +0  +0 +46  +0 
SUN_POSTN:       115.05d {+07h 40m 11s}  +21.44d {+21d 26' 28"}
SUN_DIST:        118.38 [deg]   Sun_angle= -8.0 [hr] (East of Sun)
MOON_POSTN:      153.18d {+10h 12m 42s}  +13.29d {+13d 17' 16"}
MOON_DIST:        82.57 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:        5.27, 40.67 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      232.95, 18.14 [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 = 114.39,17.46 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(1.0<100sec) coincident with the CALET_GBM event (trignum=1215713118).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 15 Jul 18 18:07:29 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      49
TRIGGER_NUM:     553370830
GRB_RA:          226.217d {+15h 04m 52s} (J2000),
                 226.440d {+15h 05m 46s} (current),
                 225.614d {+15h 02m 27s} (1950)
GRB_DEC:         +10.550d {+10d 33' 00"} (J2000),
                 +10.479d {+10d 28' 43"} (current),
                 +10.744d {+10d 44' 37"} (1950)
GRB_ERROR:       10.43 [deg radius, statistical plus systematic]
GRB_INTEN:       270 [cnts/sec]
DATA_SIGNIF:     11.30 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        18314 TJD;   196 DOY;   18/07/15
GRB_TIME:        65225.06 SOD {18:07:05.06} UT
GRB_PHI:         111.00 [deg]
GRB_THETA:        65.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.28
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic Transient
DETECTORS:       0,0,0, 0,0,0, 0,0,0, 1,1,1, 0,0,
SUN_POSTN:       115.05d {+07h 40m 11s}  +21.44d {+21d 26' 27"}
SUN_DIST:        105.51 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      153.18d {+10h 12m 43s}  +13.29d {+13d 17' 15"}
MOON_DIST:        71.49 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:       11.57, 54.52 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      220.37, 26.76 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180715755/quicklook/glg_lc_medres34_bn180715755.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 70.78,24.37 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=848048).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 15 Jul 18 18:07:44 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      59
TRIGGER_NUM:     553370830
GRB_RA:          234.330d {+15h 37m 19s} (J2000),
                 234.567d {+15h 38m 16s} (current),
                 233.691d {+15h 34m 46s} (1950)
GRB_DEC:          +0.390d {+00d 23' 24"} (J2000),
                  +0.330d {+00d 19' 48"} (current),
                  +0.554d {+00d 33' 13"} (1950)
GRB_ERROR:       5.14 [deg radius, statistical only]
DATA_SIGNIF:     12.90 [sigma] 
DATA_INTERVAL:   1.024 [sec]   
GRB_DATE:        18314 TJD;   196 DOY;   18/07/15
GRB_TIME:        65225.06 SOD {18:07:05.06} UT
GRB_PHI:         121.00 [deg]
GRB_THETA:        74.00 [deg]  
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       115.05d {+07h 40m 11s}  +21.44d {+21d 26' 27"}  
SUN_DIST:        117.16 [deg]   Sun_angle= -8.0 [hr] (East of Sun)
MOON_POSTN:      153.18d {+10h 12m 43s}  +13.29d {+13d 17' 12"} 
MOON_DIST:        81.54 [deg]
MOON_ILLUM:      10 [%] 
GAL_COORDS:        6.06, 42.06 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      231.86, 19.23 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180715755/quicklook/glg_lc_medres34_bn180715755.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_553370830.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.
COMMENTS:        This Notice was ground-generated -- not flight-generated.
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.
COMMENTS:
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=848048).

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Sun 15 Jul 18 18:07:48 UT
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    8107,   Sub_Num: 0
GRB_INTEN:      9.72 [sigma]   
GRB_TIME:       65223.18 SOD {18:07:03.18} UT
GRB_DATE:       18314 TJD;   196 DOY;   18/07/15
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=2.0000 and Time_Error=1.0000.
COMMENTS:
COMMENTS:       NOTE: This SPIACS event is temporally(2.0<100sec) coincident with the FERMI_GBM event (trignum=553370830). 
COMMENTS:
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2018-07/2018-07-15T18-07-03.0750-22200-23440-0.lc

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 15 Jul 18 18:10:34 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     848048,   Seg_Num: 0
GRB_RA:          235.069d {+15h 40m 17s} (J2000),
                 235.308d {+15h 41m 14s} (current),
                 234.425d {+15h 37m 42s} (1950)
GRB_DEC:          -0.925d {-00d 55' 28"} (J2000),
                  -0.984d {-00d 59' 00"} (current),
                  -0.764d {-00d 45' 49"} (1950)
GRB_DATE:        18314 TJD;   196 DOY;   18/07/15
GRB_TIME:        65225.00 SOD {18:07:05.00} UT
TRIGGER_INDEX:   207
GRB_PHI:         170.88 [deg]
GRB_THETA:        24.73 [deg]
DELTA_TIME:      12.00 [sec]
TRIGGER_DUR:     0.512 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     39.19 [sigma]
IMAGE_SIGNIF:    7.60 [sigma]
LC_URL:          sw00848048000msb.lc
SUN_POSTN:       115.05d {+07h 40m 12s}  +21.44d {+21d 26' 26"}
SUN_DIST:        118.37 [deg]   Sun_angle= -8.0 [hr] (East of Sun)
MOON_POSTN:      153.21d {+10h 12m 50s}  +13.28d {+13d 16' 43"}
MOON_DIST:        82.54 [deg]
MOON_ILLUM:      10 [%]
GAL_COORDS:        5.27, 40.67 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      232.95, 18.14 [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 = 114.39,17.46 [deg].

GCN Circular #22947
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), S. W. K Emery (UCL-MSSL), J.D. Gropp (PSU), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC), Z. Liu (NAOC/U. Leicester), D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 18:07:05 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180715A (trigger=848048). Swift could not immediately slew to the location due to the Earth limb constraint. The BAT on-board calculated location is RA, Dec 235.069, -0.925 which is
```
   RA(J2000) = 15h 40m 17s
   Dec(J2000) = -00d 55' 28"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single short peak structure with a duration of about 0.7 sec. The peak count rate was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+50.9 minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). 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/FERMI NOTICE
NOTICE_DATE:     Sun 15 Jul 18 18:16:23 UT
NOTICE_TYPE:     Fermi-GBM Final Position 
RECORD_NUM:      0
TRIGGER_NUM:     553370830
GRB_RA:          231.810d {+15h 27m 14s} (J2000),
                 232.054d {+15h 28m 13s} (current),
                 231.153d {+15h 24m 37s} (1950)
GRB_DEC:          -4.380d {-04d 22' 47"} (J2000),
                  -4.444d {-04d 26' 36"} (current),
                  -4.207d {-04d 12' 23"} (1950)
GRB_ERROR:       4.83 [deg radius, statistical only]
GRB_DATE:        18314 TJD;   196 DOY;   18/07/15
GRB_TIME:        65225.06 SOD {18:07:05.06} UT
GRB_PHI:         119.00 [deg]
GRB_THETA:        79.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41531 (Gnd S/W Version number)
SUN_POSTN:       115.05d {+07h 40m 13s}  +21.44d {+21d 26' 24"}
SUN_DIST:        116.72 [deg]   Sun_angle= -7.8 [hr] (East of Sun)
MOON_POSTN:      153.27d {+10h 13m 04s}  +13.26d {+13d 15' 44"}
MOON_DIST:        80.16 [deg] 
MOON_ILLUM:      10 [%] 
GAL_COORDS:      359.01, 40.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      230.56, 13.98 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180715755/quicklook/glg_lc_medres34_bn180715755.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180715755/quicklook/glg_locplot_all_bn180715755.png
COMMENTS:        Fermi-GBM Final Position.
COMMENTS:        This Notice was ground-generated -- not flight-generated.
COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.       
COMMENTS:        This notice was generated completely by automated pipeline processing.     
COMMENTS:        This is likely a Short GRB.
COMMENTS:        
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=8107).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 15 Jul 18 19:07:36 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     848048,   Seg_Num: 0
POINT_RA:        235.031d {+15h 40m 07s} (J2000)
POINT_DEC:        -0.902d {-00d 54' 05"} (J2000)
IMG_START_DATE:  18314 TJD;   196 DOY;   18/07/15
IMG_START_TIME:  68392.83 SOD {18:59:52.83} UT,   3167.8 [sec] since BAT Trigger Time
COUNTS:          193    Min_needed= 20
STD_DEV:         33.48   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        2    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 15 Jul 18 19:35:52 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     848048,   Seg_Num: 0
POINT_RA:        235.029d {+15h 40m 07s} (J2000)
POINT_DEC:        -0.902d {-00d 54' 07"} (J2000)
POINT_ROLL:      293.967d
IMG_START_DATE:  18314 TJD;   196 DOY;   18/07/15
IMG_START_TIME:  69537.32 SOD {19:18:57.32} UT,   4312.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.434
N_STARS:         175
X_OFFSET:        172 [pixels]
Y_OFFSET:        687 [pixels]
X_MAX:           1131 [pixels]
Y_MAX:           1646 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00848048000msufc4312.fits
SUN_POSTN:       115.11d {+07h 40m 26s}  +21.43d {+21d 25' 52"}
SUN_DIST:        118.28 [deg]   Sun_angle= -8.0 [hr] (East of Sun)
MOON_POSTN:      154.07d {+10h 16m 18s}  +13.03d {+13d 02' 04"}
MOON_DIST:        81.64 [deg]
MOON_ILLUM:      11 [%]
GAL_COORDS:        5.26, 40.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      232.91, 18.15 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 15 Jul 18 19:36:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     848048,   Seg_Num: 0
POINT_RA:        235.029d {+15h 40m 07s} (J2000)
POINT_DEC:        -0.902d {-00d 54' 07"} (J2000)
POINT_ROLL:      293.967d
IMG_START_DATE:  18314 TJD;   196 DOY;   18/07/15
IMG_START_TIME:  69537.32 SOD {19:18:57.32} UT,   4312.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.434
N_STARS:         175
X_OFFSET:        172 [pixels]
Y_OFFSET:        687 [pixels]
X_MAX:           1131 [pixels]
Y_MAX:           1646 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00848048000msufc4312.fits
SUN_POSTN:       115.11d {+07h 40m 26s}  +21.43d {+21d 25' 52"}
SUN_DIST:        118.28 [deg]   Sun_angle= -8.0 [hr] (East of Sun)
MOON_POSTN:      154.08d {+10h 16m 19s}  +13.03d {+13d 02' 01"}
MOON_DIST:        81.64 [deg]
MOON_ILLUM:      11 [%]
GAL_COORDS:        5.26, 40.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      232.91, 18.15 [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 15 Jul 18 19:37:14 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     848048,   Seg_Num: 0
POINT_RA:        235.029d {+15h 40m 07s} (J2000)
POINT_DEC:        -0.902d {-00d 54' 07"} (J2000)
ROLL:            293.967d
IMG_START_DATE:  18314 TJD;   196 DOY;   18/07/15
IMG_START_TIME:  69537.32 SOD {19:18:57.32} UT,   4312.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     553375158
X_OFFSET:        491 [pixels]
Y_OFFSET:        1006 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       651
Y_GRB_POS:       1166
BINNING_INDEX:   1
IM_URL:          sw00848048000msuni4334.fits
SUN_POSTN:       115.11d {+07h 40m 27s}  +21.43d {+21d 25' 51"}
SUN_DIST:        118.27 [deg]   Sun_angle= -8.0 [hr] (East of Sun)
MOON_POSTN:      154.09d {+10h 16m 21s}  +13.03d {+13d 01' 50"}
MOON_DIST:        81.63 [deg]
MOON_ILLUM:      11 [%]
GAL_COORDS:        5.26, 40.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      232.91, 18.15 [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 15 Jul 18 19:37:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     848048,   Seg_Num: 0
POINT_RA:        235.029d {+15h 40m 07s} (J2000)
POINT_DEC:        -0.902d {-00d 54' 07"} (J2000)
ROLL:            293.967d
IMG_START_DATE:  18314 TJD;   196 DOY;   18/07/15
IMG_START_TIME:  69537.32 SOD {19:18:57.32} UT,   4312.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     553375158
X_OFFSET:        491 [pixels]
Y_OFFSET:        1006 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       651
Y_GRB_POS:       1166
BINNING_INDEX:   1
IM_URL:          sw00848048000msuni4334.fits
SUN_POSTN:       115.11d {+07h 40m 27s}  +21.43d {+21d 25' 51"}
SUN_DIST:        118.27 [deg]   Sun_angle= -8.0 [hr] (East of Sun)
MOON_POSTN:      154.09d {+10h 16m 22s}  +13.03d {+13d 01' 48"}
MOON_DIST:        81.63 [deg]
MOON_ILLUM:      11 [%]
GAL_COORDS:        5.26, 40.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      232.91, 18.15 [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 #22948
S. Campana (INAF-OAB), G. Cusumano (INAF-IASF PA), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), D.N. Burrows (PSU) and J.A. Kennea (PSU) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 180715A at 18:59:52.8 UT, 3167.8 seconds after the BAT trigger. No source was detected in 1.1 ks of promptly downlinked data, which covered 73% of the BAT error circle. We are waiting for the full dataset to detect and localise the XRT counterpart.
GCN Circular #22949
C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:
One of the LCO 1-m units at Sutherland Observatory (South Africa) automatically began observing Swift GRB 180715A (Ukwatta et al. GCN 22947) on July 15, 18:17:37 UT (10.5 minutes after the GRB trigger time) with the SDSS r' filter. Within the Swift-BAT error circle, well within the glare of a 8-mag catalogued object we clearly detect a source which is not present in the SDSS catalogue at the following position:
```
RA(J2000)=� 15:40:22.30
DEC(J2000)= -00:54:44.4
```
with an error radius of ~1".
GCN Circular #22950
J.Lyman, D.Steeghs (U. Warwick), G.Ramsay (Armagh O.), M.Dyer (U. Sheffield), K.Ulaczyk, B.Gompertz, A.Levan, R.Cutter (U. Warwick) K. Ackley, D.Galloway, E.Rol (Monash U.), V.Dhillon (U. Sheffield), P.O'Brien, N.Tanvir (U. Leicester), S.Poshyachinda (NARIT), D.Pollacco (U. Warwick), E.Thrane (Monash U.)
report on behalf of the GOTO collaboration:
In response to GRB 180715A (Ukwatta et al. GCN 22947), the Gravitational-wave Optical Transient Observer (GOTO) observed the field near the Swift BAT detection.
Observations started at 2018-07-15T22:37:10 UT (4.5 hours after the burst) consisted of a set of 3x120s exposures in our wide L filter (400-700nm). We detect the source identified by Guidorzi et al. (GCN 22949) but note that this source appears in PanSTARRS images of the field and in the Gaia catalogue and is thus likely to be unrelated. We did not detect any other uncatalogued source within the BAT localisation uncertainty. A preliminary analysis of the stacked image was used to derive a 5-sigma upper limit of V>20.5 mag.
GOTO is operated at the La Palma observing facilities of the University of Warwick on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT) and the Instituto de Astrofisica de Canarias (IAC)
https://goto-observatory.org/
GCN Circular #22951
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180715A (trigger #848048) (Ukwatta et al., GCN Circ. 22947). The BAT ground-calculated position is RA, Dec = 235.085, -0.899 deg which is
```
  RA(J2000)  =  15h 40m 20.5s
  Dec(J2000) = -00d 53' 57.6"
```
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 85%.
The mask-weighted light curve shows a double-peaked structure that starts at ~T-0.1 and ends at ~T+0.6, The two peaks occur at ~T+0.1 and ~T+0.5, respectively. T90 (15-350 keV) is 0.68 +- 0.09 sec (estimated error including systematics).
The time-averaged spectrum from T-0.14 to T+0.63 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.74 +- 0.27. The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.26 sec in the 15-150 keV band is 1.2 +- 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/848048/BA/
GCN Circular #22952
R. Hamburg (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 18:07:05.06 UT on 15 July 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 180715A (trigger 553370830 / 180715755) which was also detected by the Swift/BAT (Ukwatta et al. 2018, GCN 22947). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 75 degrees.
The GBM light curve shows a single structured peak with a duration (T90) of about 0.7 s (50-300 keV). The time-averaged spectrum from T0-0.19 to T+0.51 s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -0.14 +/- 0.21 and the cutoff energy, parameterized as Epeak, is 852 +/- 182 keV.
The event fluence (10-1000 keV) in this time interval is (1.7 +/- 0.1)E-06 erg/cm^2. The 64-ms peak photon flux measured starting from T0-0.064s in the 10-1000 keV band is 8.4 +/- 1.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #22953
J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), S.L. Gibson (U. Leicester), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift-XRT team:
We have analysed 14 ks of Photon Counting (PC) mode XRT data for the Swift/BAT-detected burst GRB 180715A (Ukwatta et al. GCN Circ. 22951), collected between T0+11.0 ks and T0+67.7 ks.
Five uncatalogued X-ray sources have been detected consistent with being within 296 arcsec of the Swift/BAT position, however none of them is above the RASS limit or shows definitive signs of fading. Therefore, at the present time we cannot identify which, if any, is the afterglow.
The 3-sigma upper limit at the BAT position is 9.5x10^-4 ct/sec.
Details of these sources are given below:
Source 5:
```
  RA (J2000.0):  235.1362  =  15:40:32.68
  Dec (J2000.0): -0.9559  =  -00:57:21.2
  Error: 6.1 arcsec (radius, 90% conf.)
  Count-rate: (5.4 [+2.7, -2.1])e-4 ct s^-1   
  Distance: 266 arcsec from Swift/BAT position.
```
Source 7:
```
  RA (J2000.0):  235.0967  =  15:40:23.21
  Dec (J2000.0): -0.9760  =  -00:58:33.6
  Error: 5.4 arcsec (radius, 90% conf.)
  Count-rate: (7.4 [+3.2, -2.6])e-4 ct s^-1   
  Distance: 210 arcsec from Swift/BAT position.
```
Source 8:
```
  RA (J2000.0):  235.1256  =  15:40:30.15
  Dec (J2000.0): -0.8791  =  -00:52:44.8
  Error: 6.5 arcsec (radius, 90% conf.)
  Count-rate: (8.2 [+3.3, -2.7])e-4 ct s^-1   
  Distance: 261 arcsec from Swift/BAT position.
  Flux: (5.6 [+2.3, -1.8])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)
```
Source 10:
```
  RA (J2000.0):  234.9980  =  15:39:59.51
  Dec (J2000.0): -0.9504  =  -00:57:01.5
  Error: 5.0 arcsec (radius, 90% conf.)
  Count-rate: (1.85 [+0.46, -0.42])e-3 ct s^-1	 
  Distance: 272 arcsec from Swift/BAT position.
  Flux: (8.9 [+2.2, -2.0])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)
```
Source 11:
```
  RA (J2000.0):  235.0291  =  15:40:6.98
  Dec (J2000.0): -0.9196  =  -00:55:10.6
  Error: 10.7 arcsec (radius, 90% conf.)
  Count-rate: (4.4 [+2.5, -2.0])e-4 ct s^-1   
  Distance: 144 arcsec from Swift/BAT position.
```
Ten uncatalogued sources were also detected too far from the GRB position to be likely afterglow candidates.
The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at http://www.swift.ac.uk/ToO_GRBs/00848048.
This circular is an official product of the Swift-XRT team.
GCN Circular #22954
Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), William H. Lee (UNAM), Carlos Rom�n-Z��iga (UNAM), Alexander Kutyrev (GSFC), and Eleonora Troja (GSFC) report:
We observed the field of the short GRB 180715A (Ukwatta et al., GCN Circ. 22947) with the COATLI 50-cm telescope and interim imager at the Observatorio Astron�mico Nacional on the Sierra de San Pedro M�rtir (http://coatli.astroscu.unam.mx) from 2018-07-16 03:40:25 to 08:07:12 UTC (9.55 to 14.00 hours after the trigger), obtaining a total of 3.33 hours of exposure in the w filter.
We do not detect any optical sources coincident with the five X-ray sources reported by Kennea et al. (GCN Circ. 22953) to a 5-sigma limiting magnitude of
w > 22.4
This magnitude is calibrated against the USNO-B1 catalog (adjusted to an approximate AB system) and is not corrected for Galactic extinction in the direction of the GRB.
We thank the COATLI technical team (Fernando �ngeles, Oscar Chapa, Salvador Cuevas, Alejandro Farah, Jorge Fuentes, Rosal�a Langarica, Fernando Quir�s, and Carlos Tejada) and the staff of the Observatorio Astron�mico Nacional.
GCN Circular #22955
C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:
With reference to the observation of our previous report (Guidorzi et al. GCN 22949), within the XRT error circles of the five X-ray sources (Kennea et al. GCN 22953) we found no uncatalogued source down to r'>20.0 mag at a mid time of 0.28 hours after the GRB trigger time (5x120s exposure), as calibrated against nearby SDSS objects.
GCN Circular #22956
S. Torii (Waseda U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena) and the CALET collaboration:
The short, hard GRB 180715A (Swift-BAT trigger #848048: Ukwatta, et al., GCN Circ. 22947, 22951; Fermi-GBM detection: Hamburg and Meegan, GCN Circ. 22952) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 18:07:04.799 UTC on 15 July 2018. The burst signal was seen by all CGBM detectors.
The burst light curve shows a double-peaked pulse which starts at T+0.192 sec and ends at T+0.784 sec. The T90 and the T50 durations measured by the SGM data are 0.53 +- 0.07 sec and 0.34 +- 0.12 sec (40-1000 keV), respectively.
The time-averaged spectrum of the burst (measured by the SGM from T+0.192 sec to T+0.784 sec) is best fit in the 0.03-10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.64(-0.37, +0.46) and Ep = 707(-195, +337) keV (chi2 = 29.4/32 dof). The resulting fluence in this energy range is 2.32(-0.50, +0.65)x10^-6 erg/cm2. The quoted errors are at 90% CL.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1215713118/
All the quoted values are preliminary.
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #22967
M. H. Siegel (PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180715A 4312 s after the BAT trigger (Ukwatta et al., GCN Circ. 22947). No optical afterglow consistent with the BAT position (Ukwatta et al., GCN Circ. 22951) 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          4312         4462          147         >20.6
white             4312         5695          344         >21.0
v                 4469         4669          197         >19.1
b                 5290         5490          197         >20.1
u                 5085         5284          197         >19.8
w1                4879         5079          197         >19.5
m2                4674         4874          197         >19.7
w2                5701         5726           25         >18.7
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.13 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #22968
W. Fong (Northwestern Univ.), A. J. Levan (U. Warwick), R. Chornock (Ohio Univ.) report on behalf of a larger collaboration:
"We observed the location of the short-duration GRB 180715A (Ukwatta et al., GCN 22947) with the twin Gemini-North and Gemini-South 8-meter telescopes located on Mauna Kea, Hawaii and Cerro Pachon, Chile, respectively. We used the pair of Gemini Multi-Object Spectrographs (GMOS) to obtain r-band imaging at mid-times of 5.9 hr, 13.0 hr and 1.2 days post-burst, spanning 2018 Jul 16-Jul 17 UT. Our observational coverage of the refined Swift/BAT position (90% containment; Ukwatta et al., GCN 22951) as well as the uncatalogued Swift/XRT sources (Kennea et al., GCN 22953) is as follows:
```
5.9 hr: ~70% of BAT position, XRT S7 and S11
13.0 hr: 100% of BAT position, XRT S8
1.2 days: 100% of BAT position, XRT S8
```
We identify optical sources in and around each of these 3 XRT sources (90% containment; Kennea et al., GCN 22953) in our imaging; however, all sources are clearly visible in archival PS1 or SDSS imaging and have measured magnitudes within +/- 0.3 mag of known values. Furthermore, we do not detect any uncatalogued optical sources in or around these 3 XRT sources to 3-sigma limits of r>23.6 AB mag (S7 and S11 at 5.9 hr) and r>25.2 AB mag (S8 at 13.0 hr). The photometry is calibrated to SDSS DR12 and is not corrected for Galactic extinction in the direction of the burst.
Finally, we perform image subtraction between the observations at 13.0 hr and 1.2 days, which each provide full coverage of the refined BAT position (90% containment). We note that there is significant contamination from the 8th mag star that affects ~20% of the BAT position in the subtraction. For the remaining, uncontaminated region, we place a 3-sigma limit of r>24 AB mag on the optical afterglow of GRB 180715A at 13.0 hr after the burst.
We thank the Gemini-North and Gemini-South queue observers and staff for their rapid assistance with these observations."
GCN Circular #22978
D. Vlasenko, N.Tiurina, E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Kuznetsov, V.Chazov, I. Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov Lomonosov Moscow State University,SAI 4 A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
R. Podesta, F. Podesta, C. Lopez, C.Francile Observatorio Astronomico Felix Aguilar (OAFA)
H.Levato, Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
O. Gres, N.M.Budnev , Yu.Ishmuhametova Irkutsk State University (ISU)
A. Gabovich, V. Yurkov, Yu. Sergienko Blagoveschensk Educational State University (BSPU)
D. Buckley, South African Astronomical Observatory (SAAO)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias (IAC)
MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (SAI Crimea astronomical station) was pointed to the GRB180715A (Ukwatta et al., GCN Circ #22947) 96 sec after trigger time at 2018-07-15 18:08:41 UT as sun altitude was -6.95 dec first image was at 2018-07-15 18:30:37. On our first (180s exposure) set we do not found optical transients within Swift error-box (ra=235.069 dec=-0.925 r=0.05) brighter then 20.7.
The observations made on zenit distance = 44.16 degrees, galaxy latitude b = 40,1 degree. The moon (10 % bright part) is 8 degrees above the horizon. The distance between moon and object is 82 The sun altitude is -9.85 degree. The object can be observed till 2018-07-15 21:36:28
MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical observatory) was pointed to the GRB180715A (Ukwatta et al., GCN Circ #22947) 495 sec after trigger time at 2018-07-15 18:15:20 UT . On our first (100s exposure) set we do not found optical transients within Swift error-box (ra=235.069 dec=-0.925 r=0.05) brighter then 20.8.
The observations made on zenit distance = 57.43 degrees, galaxy latitude b = 40.1 degree. The moon (10 % bright part) is 6.5 degrees above the horizon. The distance between moon and object is 83 The sun altitude is -28.83 degree. The object can be observed till 2018-07-15 22:48:22.
The visibility GRB error box (coord: 235.069 -0.925 error_box: 0.05) at trigger time at different MASTER sites:
```
obj:  44.19 sun: -6.73 - Tavrida (Crimea, Russia)
obj:  36.94 sun:  23.52 - IAC, Teide (Tenerife,Spain)
obj:  57.43 sun: -28.83 - SAAO (Sutherland, SA)
obj:  43.89 sun: -11.87 - Kislovodsk (Russia)
obj:  27.30 sun: -7.55 - Ural (Kourovka, Russia)
obj:  9.49  sun: -15.74 - Tunka (near Baykal Lake, Russia)
obj: -5.64  sun: -10.73 - Amur(Blagoveschensk)
obj: -7.22  sun:  32.97 - OAFA (Argentina)
```
The message may be cited.
GCN Circular #23012
V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:
Analysis of Astrosat CZTI data showed the detection of a GRB 180715A, which was also detected by Swift (Palmer D. et al., GCN 22947), Fermi-GBM (Hamburg R. et. al., GCN 22952) and CALET (Torii S. et al.,GCN 22956).
The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission with peak at 18:06:59.5 UT. The measured peak count rate is 403.6 cts/s above the background in combined data of four quadrants, with a total of 408 cts. The local mean background count rate was 476.4 cts/s. Using cumulative rates, we measure a T90 of 0.9 s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
GCN Circular #23059
N. Cannady (LSU), K. Yoshikawa, Y. Asaoka (Waseda U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU), S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena) and the CALET collaboration:
Using the CALET CALorimeter (CAL) data, we report GeV gamma-ray search analysis associated to GRB 180715A (Ukwatta, et al., GCN Circ. 22947, 22951; Hamburg and Meegan, GCN Circ. 22952; Torii et al., GCN Circ. 22956)
The CAL was operating in low energy trigger mode at the trigger time of the CALET Gamma-ray Burst Monitor (CGBM). We have searched for gamma-ray events in the 1-10 GeV band from -60 sec to +60 sec from the CGBM trigger time using the Swift-BAT position (Ukwatta et al. GCN Circ. 22951) and found no candidates. The 90% upper limit of CAL is 3.2e-7 erg/cm2/s (1-10 GeV) assuming a power-law spectrum of a photon index of -2.
All the quoted values are preliminary.
GCN Circular #23217
J. Bright (Oxford), K. P. Mooley (NRAO, Caltech; Jansky Fellow), R. P. Fender (Oxford)
We observed the field of short GRB 180718A (Ukwatta et al., GCN 22947) with the AMI Large Array at 15 GHz. Our observations on 2018 Jul 16.80, Jul 17.73, Jul 19.80 and Jul 23.80 (UT) (1.05 d, 1.98 d, 4.05 d and 7.05 d post-burst) does not reveal any potential afterglow candidate consistent with the BAT location (Ukwatta et al., GCN 22947), and our 3sigma upper limit to the flux density are 137 uJy, 186 uJy, 106 uJy and 146 uJy respectively.
We thank the MRAO staff for scheduling these observations. Results from the AMI Short GRB program are posted on the AMI-GRB database available at http://4pisky.org/ami-grb/.

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Jochen Greiner, last update: 10-Sep-2018 [Disclaimer]