Gamma-ray Burst 170728B

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Jul 17 23:03:33 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     765130,   Seg_Num: 0
GRB_RA:          238.044d {+15h 52m 11s} (J2000),
                 238.040d {+15h 52m 10s} (current),
                 238.060d {+15h 52m 14s} (1950)
GRB_DEC:         +70.142d {+70d 08' 32"} (J2000),
                 +70.091d {+70d 05' 26"} (current),
                 +70.290d {+70d 17' 23"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       1652 [cnts]    Image_Peak=50 [image_cnts]
TRIGGER_DUR:     0.256 [sec] 
TRIGGER_INDEX:   126     E_range: 50-350 keV
BKG_INTEN:       19025 [cnts]
BKG_TIME:        82988.55 SOD {23:03:08.55} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17962 TJD;   209 DOY;   17/07/28
GRB_TIME:        82999.43 SOD {23:03:19.43} UT
GRB_PHI:          10.00 [deg]
GRB_THETA:        55.29 [deg]
SOLN_STATUS:     0x20000083
RATE_SIGNIF:     41.55 [sigma]
IMAGE_SIGNIF:    6.73 [sigma]
MERIT_PARAMS:     +1  +0  +0  -2  +3  -3  +0  +0 -19  +0 
SUN_POSTN:       128.42d {+08h 33m 42s}  +18.76d {+18d 45' 30"}
SUN_DIST:         78.81 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.29d {+13h 09m 09s}   -2.82d {-02d 49' 02"}
MOON_DIST:        77.79 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.62, 39.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      148.61, 77.84 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 228.26,-13.88 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(0.0<100sec) coincident with the FERMI_GBM event (trignum=522975804).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 28 Jul 17 23:04:16 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      59
TRIGGER_NUM:     522975804
GRB_RA:          244.740d {+16h 18m 58s} (J2000),
                 244.658d {+16h 18m 38s} (current),
                 244.980d {+16h 19m 55s} (1950)
GRB_DEC:         +73.960d {+73d 57' 36"} (J2000),
                 +73.918d {+73d 55' 05"} (current),
                 +74.078d {+74d 04' 42"} (1950)
GRB_ERROR:       1.48 [deg radius, statistical only]
DATA_SIGNIF:     43.00 [sigma]
DATA_INTERVAL:   0.256 [sec]
GRB_DATE:        17962 TJD;   209 DOY;   17/07/28
GRB_TIME:        82999.43 SOD {23:03:19.43} UT
GRB_PHI:         144.00 [deg]
GRB_THETA:        30.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       128.43d {+08h 33m 42s}  +18.76d {+18d 45' 29"}
SUN_DIST:         78.87 [deg]   Sun_angle= -7.7 [hr] (East of Sun)
MOON_POSTN:      197.29d {+13h 09m 10s}   -2.82d {-02d 49' 09"}
MOON_DIST:        81.94 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      107.31, 36.16 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      127.62, 78.86 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170728961/quicklook/glg_lc_medres34_bn170728961.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_522975804.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        Bright hard burst in the GBM.  
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.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 28 Jul 17 23:04:04 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      48
TRIGGER_NUM:     522975804
GRB_RA:          225.983d {+15h 03m 56s} (J2000),
                 226.016d {+15h 04m 04s} (current),
                 225.894d {+15h 03m 35s} (1950)
GRB_DEC:         +69.967d {+69d 58' 00"} (J2000),
                 +69.899d {+69d 53' 55"} (current),
                 +70.160d {+70d 09' 37"} (1950)
GRB_ERROR:       5.82 [deg radius, statistical plus systematic]
GRB_INTEN:       1648 [cnts/sec]
DATA_SIGNIF:     38.50 [sigma]
INTEG_TIME:      0.256 [sec]
GRB_DATE:        17962 TJD;   209 DOY;   17/07/28
GRB_TIME:        82999.43 SOD {23:03:19.43} UT
GRB_PHI:         130.00 [deg]
GRB_THETA:        30.00 [deg]
DATA_TIME_SCALE: 0.2560 [sec]
HARD_RATIO:      0.57
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       0,0,0, 0,0,0, 1,0,0, 1,0,0, 0,0,
SUN_POSTN:       128.43d {+08h 33m 42s}  +18.76d {+18d 45' 29"}
SUN_DIST:         74.99 [deg]   Sun_angle= -6.5 [hr] (East of Sun)
MOON_POSTN:      197.29d {+13h 09m 10s}   -2.82d {-02d 49' 07"}
MOON_DIST:        75.24 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      108.07, 43.14 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      148.18, 73.73 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170728961/quicklook/glg_lc_medres34_bn170728961.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 213.10,23.77 [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=765130).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Jul 17 23:06:50 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     765130,   Seg_Num: 0
GRB_RA:          238.044d {+15h 52m 11s} (J2000),
                 238.040d {+15h 52m 10s} (current),
                 238.060d {+15h 52m 14s} (1950)
GRB_DEC:         +70.142d {+70d 08' 32"} (J2000),
                 +70.091d {+70d 05' 26"} (current),
                 +70.290d {+70d 17' 23"} (1950)
GRB_DATE:        17962 TJD;   209 DOY;   17/07/28
GRB_TIME:        82999.43 SOD {23:03:19.43} UT
TRIGGER_INDEX:   126
GRB_PHI:          10.00 [deg]
GRB_THETA:        55.29 [deg]
DELTA_TIME:      32.00 [sec]
TRIGGER_DUR:     0.256 [sec] 
SOLN_STATUS:     0x83
RATE_SIGNIF:     41.55 [sigma]
IMAGE_SIGNIF:    6.73 [sigma]
LC_URL:          sw00765130000msb.lc
SUN_POSTN:       128.43d {+08h 33m 42s}  +18.76d {+18d 45' 28"}
SUN_DIST:         78.81 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.31d {+13h 09m 15s}   -2.83d {-02d 49' 36"}
MOON_DIST:        77.80 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.62, 39.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      148.61, 77.84 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 228.26,-13.88 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Jul 17 23:13:18 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     765130,   Seg_Num: 0
POINT_RA:        237.960d {+15h 51m 50s} (J2000)
POINT_DEC:       +70.149d {+70d 08' 55"} (J2000)
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83468.28 SOD {23:11:08.28} UT,   468.9 [sec] since BAT Trigger Time
COUNTS:          15    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:     Fri 28 Jul 17 23:15:16 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     765130,   Seg_Num: 0
POINT_RA:        237.960d {+15h 51m 50s} (J2000)
POINT_DEC:       +70.149d {+70d 08' 56"} (J2000)
POINT_ROLL:      294.534d
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83472.73 SOD {23:11:12.73} UT,   473.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.448
N_STARS:         24
X_OFFSET:        316 [pixels]
Y_OFFSET:        709 [pixels]
X_MAX:           1275 [pixels]
Y_MAX:           1668 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00765130000msufc0473.fits
SUN_POSTN:       128.43d {+08h 33m 44s}  +18.76d {+18d 45' 23"}
SUN_DIST:         78.78 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.38d {+13h 09m 32s}   -2.85d {-02d 51' 03"}
MOON_DIST:        77.79 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.64, 39.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      148.58, 77.81 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Jul 17 23:15:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     765130,   Seg_Num: 0
POINT_RA:        237.960d {+15h 51m 50s} (J2000)
POINT_DEC:       +70.149d {+70d 08' 56"} (J2000)
POINT_ROLL:      294.534d
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83472.73 SOD {23:11:12.73} UT,   473.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.448
N_STARS:         24
X_OFFSET:        316 [pixels]
Y_OFFSET:        709 [pixels]
X_MAX:           1275 [pixels]
Y_MAX:           1668 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00765130000msufc0473.fits
SUN_POSTN:       128.43d {+08h 33m 44s}  +18.76d {+18d 45' 23"}
SUN_DIST:         78.78 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.39d {+13h 09m 33s}   -2.85d {-02d 51' 06"}
MOON_DIST:        77.79 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.64, 39.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      148.58, 77.81 [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 28 Jul 17 23:16:43 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     765130,   Seg_Num: 0
POINT_RA:        237.960d {+15h 51m 50s} (J2000)
POINT_DEC:       +70.149d {+70d 08' 56"} (J2000)
ROLL:            294.534d
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83472.73 SOD {23:11:12.73} UT,   473.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     522976292
X_OFFSET:        635 [pixels]
Y_OFFSET:        1028 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       795
Y_GRB_POS:       1188
BINNING_INDEX:   1
IM_URL:          sw00765130000msuni0493.fits
SUN_POSTN:       128.43d {+08h 33m 44s}  +18.76d {+18d 45' 22"}
SUN_DIST:         78.78 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.40d {+13h 09m 35s}   -2.86d {-02d 51' 18"}
MOON_DIST:        77.79 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.64, 39.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      148.58, 77.81 [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 28 Jul 17 23:16:52 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     765130,   Seg_Num: 0
POINT_RA:        237.960d {+15h 51m 50s} (J2000)
POINT_DEC:       +70.149d {+70d 08' 56"} (J2000)
ROLL:            294.534d
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83472.73 SOD {23:11:12.73} UT,   473.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     522976292
X_OFFSET:        635 [pixels]
Y_OFFSET:        1028 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       795
Y_GRB_POS:       1188
BINNING_INDEX:   1
IM_URL:          sw00765130000msuni0493.fits
SUN_POSTN:       128.43d {+08h 33m 44s}  +18.76d {+18d 45' 22"}
SUN_DIST:         78.78 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.40d {+13h 09m 35s}   -2.86d {-02d 51' 20"}
MOON_DIST:        77.79 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.64, 39.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      148.58, 77.81 [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:     Fri 28 Jul 17 23:20:03 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     765130,   Seg_Num: 0
GRB_RA:          237.9836d {+15h 51m 56.06s} (J2000),
                 237.9797d {+15h 51m 55.12s} (current),
                 237.9986d {+15h 52m 00.33s} (1950)
GRB_DEC:         +70.1212d {+70d 07' 16.3"} (J2000),
                 +70.0693d {+70d 04' 09.5"} (current),
                 +70.2688d {+70d 16' 07.5"} (1950)
GRB_ERROR:       3.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83701.00 SOD {23:15:01.00} UT,   701.6 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       128.44d {+08h 33m 45s}  +18.76d {+18d 45' 20"}
SUN_DIST:         78.80 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.42d {+13h 09m 42s}   -2.86d {-02d 51' 53"}
MOON_DIST:        77.78 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.61, 39.97 [deg] galactic lon,lat of the burst
ECL_COORDS:      148.71, 77.82 [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:     Fri 28 Jul 17 23:21:32 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     765130,   Seg_Num: 0
POINT_RA:        237.955d {+15h 51m 49s} (J2000)
POINT_DEC:       +70.147d {+70d 08' 50"} (J2000)
POINT_ROLL:      294.532d
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83875.61 SOD {23:17:55.61} UT,   876.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.592
N_STARS:         76
X_OFFSET:        76 [pixels]
Y_OFFSET:        469 [pixels]
X_MAX:           1515 [pixels]
Y_MAX:           1908 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00765130000msufc0876.fits
SUN_POSTN:       128.44d {+08h 33m 45s}  +18.76d {+18d 45' 19"}
SUN_DIST:         78.78 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.44d {+13h 09m 44s}   -2.87d {-02d 52' 08"}
MOON_DIST:        77.79 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.64, 39.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      148.59, 77.81 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Jul 17 23:21:46 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     765130,   Seg_Num: 0
POINT_RA:        237.955d {+15h 51m 49s} (J2000)
POINT_DEC:       +70.147d {+70d 08' 50"} (J2000)
POINT_ROLL:      294.532d
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83875.61 SOD {23:17:55.61} UT,   876.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.592
N_STARS:         76
X_OFFSET:        76 [pixels]
Y_OFFSET:        469 [pixels]
X_MAX:           1515 [pixels]
Y_MAX:           1908 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00765130000msufc0876.fits
SUN_POSTN:       128.44d {+08h 33m 45s}  +18.76d {+18d 45' 19"}
SUN_DIST:         78.78 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.44d {+13h 09m 45s}   -2.87d {-02d 52' 10"}
MOON_DIST:        77.79 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.64, 39.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      148.59, 77.81 [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 28 Jul 17 23:22:08 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     765130,   Seg_Num: 0
GRB_RA:          237.9810d {+15h 51m 55.43s} (J2000),
                 237.9771d {+15h 51m 54.49s} (current),
                 237.9960d {+15h 51m 59.04s} (1950)
GRB_DEC:         +70.1219d {+70d 07' 18.8"} (J2000),
                 +70.0700d {+70d 04' 12.0"} (current),
                 +70.2695d {+70d 16' 10.1"} (1950)
GRB_ERROR:       2.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83701.00 SOD {23:15:01.00} UT,   701.6 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       128.44d {+08h 33m 45s}  +18.76d {+18d 45' 19"}
SUN_DIST:         78.80 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.44d {+13h 09m 46s}   -2.87d {-02d 52' 14"}
MOON_DIST:        77.78 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.61, 39.97 [deg] galactic lon,lat of the burst
ECL_COORDS:      148.71, 77.82 [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 28 Jul 17 23:22:55 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     765130,   Seg_Num: 0
POINT_RA:        237.955d {+15h 51m 49s} (J2000)
POINT_DEC:       +70.147d {+70d 08' 50"} (J2000)
ROLL:            294.532d
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83875.61 SOD {23:17:55.61} UT,   876.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     522976695
X_OFFSET:        635 [pixels]
Y_OFFSET:        1028 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       795
Y_GRB_POS:       1188
BINNING_INDEX:   1
IM_URL:          sw00765130000msuni0896.fits
SUN_POSTN:       128.44d {+08h 33m 45s}  +18.76d {+18d 45' 18"}
SUN_DIST:         78.78 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.45d {+13h 09m 47s}   -2.87d {-02d 52' 22"}
MOON_DIST:        77.79 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.64, 39.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      148.59, 77.81 [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 28 Jul 17 23:23:07 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     765130,   Seg_Num: 0
POINT_RA:        237.955d {+15h 51m 49s} (J2000)
POINT_DEC:       +70.147d {+70d 08' 50"} (J2000)
ROLL:            294.532d
IMG_START_DATE:  17962 TJD;   209 DOY;   17/07/28
IMG_START_TIME:  83875.61 SOD {23:17:55.61} UT,   876.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     522976695
X_OFFSET:        635 [pixels]
Y_OFFSET:        1028 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       795
Y_GRB_POS:       1188
BINNING_INDEX:   1
IM_URL:          sw00765130000msuni0896.fits
SUN_POSTN:       128.44d {+08h 33m 45s}  +18.76d {+18d 45' 18"}
SUN_DIST:         78.78 [deg]   Sun_angle= -7.3 [hr] (East of Sun)
MOON_POSTN:      197.45d {+13h 09m 48s}   -2.87d {-02d 52' 24"}
MOON_DIST:        77.80 [deg]
MOON_ILLUM:      34 [%]
GAL_COORDS:      104.64, 39.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      148.59, 77.81 [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 #21371
S. B. Cenko (GSFC), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), A. Cholden-Brown (PSU), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 23:03:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170728B (trigger=765130). Due to an observing constraint, Swift executed a 6-min delayed slew to the burst. The BAT on-board calculated location is RA, Dec 238.044, +70.142, which is
```
   RA(J2000)  =  15h 52m 11s
   Dec(J2000) = +70d 08' 32"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 1 sec. The peak count rate was ~5500 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 23:11:08.2 UT, 468.9 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 237.9813, 70.1222 which is equivalent to:
```
   RA(J2000)  = 15h 51m 55.52s
   Dec(J2000) = +70d 07' 19.9"
```
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 104 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. No spectrum from the promptly downlinked event data is yet available to determine the column density.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 473 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 none of the XRT error circle. 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 0.03.
Burst Advocate for this burst is S. B. Cenko (brad.cenko 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 Circular #21372
P. D'Avanzo (INAF-OAB), V. D'Elia (INAF/OAR & ASI/ASDC), M. Cecconi, H. Stoev (INAF-TNG) report on behalf of the CIBO collaboration:
We observed the field of the short GRB 170728B (Cenko et al., GCN Circ. 21371) with the 3.6m Telescopio Nazionale Galileo (TNG) equipped with DOLoRes. Observations were carried out in the r-sdss filter. Observations started Jul 28 at 23:55:49 UT (~52.5 minutes after the burst) and consist in a single image lasting 300 seconds.
Inside the enhanced XRT position (http://www.swift.ac.uk/xrt_positions/) we detect a candidate optical afterglow. From preliminary photometry we estimate a magnitude r(AB)~20.6 (calibrated against nearby stars reported in the PAN-STARSS catalogue).
GCN Circular #21373
P. D'Avanzo (INAF-OAB), H. Stoev, M. Cecconi (INAF-TNG, V. D'Elia (INAF/OAR & ASI/ASDC) report on behalf of the CIBO collaboration:
We report here the position of the optical afterglow candidate of the short GRB 170728B (D=E2=80=99Avanzo et al. GCN Circ. 21372).
The source position is:
```
RA (J2000): 15:51:55.47
Dec (J2000): +70:07:21.1
+/- 0.3=E2=80=9D.=20
```
We apologize for the delay in sending this information.
GCN Circular #21374
K. E. Heintz (Univ. Iceland and DARK/NBI), N. R. Tanvir (Univ. Leicester)= , D. A. Perley (LJMU) and R. T. Rasmussen (NOT) report on behalf of a lar= ger collaboration:
We observed the field of the short GRB 170728B (Cenko et al., GCN 21371) = using the ALFOSC instrument equipped at the 2.56-m Nordic Optical Telesco= pe (NOT). We obtained a single image with the SDSS r-band consisting of a= 60 s exposure at 00:10:53 UT on 29 July, 2017 (i.e., 67.3 minutes after= the burst). We confirm the presence of the optical afterglow (P. D'Avanz= o et al., GCN 21372/21373) and from the single image we measure a magnitu= de of r(AB) =3D 20.9 +/- 0.1 mag calibrated against nearby stars from the= Pan-STARRS survey.=20
In addition, we obtained spectroscopy of the afterglow consisting of 3x12= 00 s exposures using grism no. 4, covering a spectral wavelength range of= 3200 =E2=80=94 9600 =C3=85, and a slit width of 1.3 arcsec. The trace is= faint and at this point we can not robustly determine a redshift. A sepa= rate GCN will be submitted later based on the reduced spectroscopic data.
The observations were carried out under good weather conditions at an air= mass of ~ 1.6 and a measured seeing of 0.74 arcsec.
GCN Circular #21375
C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), S. Kobayashi, I.A. Steele (LJMU) on behalf of a large collaboration report:
We began observing Swift GRB 170728B (Cenko et al. GCN 21371) on July 28, 23:06:47 UT (208 seconds since the GRB trigger) with 2-m Liverpool Telescope with RINGO3 polarimeter and IO:O camera in the SDSS R filter. We clearly detect the optical counterpart (D'Avanzo et al. GCN 21373; Heintz et al. GCN 21374) with r'=20.43 +- 0.12 mag in a 6x10s frame at a mid time of 36.5 minutes since GRB, as calibrated against nearby Pan-STARRS1 sources.
GCN Circular #21376
V. D'Elia (ASDC), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB) and S.B. Cenko report on behalf of the Swift-XRT team:
We have analysed 7.3 ks of XRT data for GRB 170728B (Cenko et al. GCN Circ. 21371), from 454 s to 14.4 ks after the BAT trigger. The data comprise 231 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The best available XRT position (using the promptly downlinked event data, the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) is RA, Dec = 237.9806, 70.1227 which is equivalent to:
```
RA (J2000): 15 51 55.35
Dec(J2000): +70 07 21.7
```
with an uncertainty of 2.0 arcsec (radius, 90% confidence).
The light curve can be modelled with an initial power-law decay with an index of alpha=0.66 (+0.08, -0.12), followed by a break at T+1874 s to an alpha of 1.20 (+/-0.07).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.94 (+/-0.12). The best-fitting absorption column is 1.7 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 3.2 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.81 (+/-0.08) and a best-fitting absorption column of 2.5 (+/-0.3) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.1 x 10^-11 (5.3 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.5 (+/-0.3) x 10^21 cm^-2
Galactic foreground: 3.2 x 10^20 cm^-2
Excess significance: 11.6 sigma
Photon index:	     1.81 (+/-0.08)
```
If the light curve continues to decay with a power-law decay index of 1.20, the count rate at T+24 hours will be 0.043 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x 10^-12 (2.3 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00765130.
This circular is an official product of the Swift-XRT team.
GCN Circular #21377
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 7030 s of XRT Photon Counting mode data and 10 UVOT images for GRB 170728B, 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 = 237.98125, +70.12230 which is equivalent to:
```
RA (J2000): 15h 51m 55.50s
Dec (J2000): +70d 07' 20.3"
```
with an uncertainty of 1.5 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 #21380
M. Yassine (LUPM,CNRS,IN2P3) and J. L. Racusin (NASA/GSFC) report on behalf of the Fermi-LAT team:
On July 28, 2017, Fermi-LAT detected high-energy emission from GRB 170728B, which triggered the Fermi-GBM (trigger 522975804) at 23:33:32 UT July, 28 2017. This burst was also detected by Swift (Cenko et al., GCN Circ. 21371).
The best LAT on-ground location is found to be
RA, Dec 238.97, 69.74 (degrees, J2000)
with an error radius of 0.53 deg (90% containment, statistical error only). This was 30 deg from the LAT boresight at the time of the trigger and triggered an autonomous repoint of the spacecraft.
The data from the Fermi-LAT is spatially and temporally correlated with the GBM emission with high significance. More than 10 photons above 100 MeV are observed within 100 seconds. The highest-energy photon is a 0.6 GeV event which is observed 9.3 seconds after the GBM trigger.
The Fermi-LAT point of contact for this burst is Manal Yassine (manal.yassine@lupm.in2p3.fr).
The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
GCN Circular #21381
L. Izzo, D.A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene (HETH/IAA-CSIC) and A. Sota (IAA-CSIC) report on behalf of a larger collaboration:
We observed the field of GRB 170728B (Cenko et al., GCN 21371) with the 1.5m OSN telescope of the Sierra Nevada Observatory (Granada, Spain). Observation consisted of a series of 300 s Ic-band exposures, starting at 00:06:02.7 UT (1.05 hr after the burst). The afterglow is detected at a position consistent with the one reported by D=E2=80=99Avanzo et al., (GCN 21373).
In the combination of the first 7x300s exposures we measure a magnitude of Ic(Vega) =3D 19.8+/- 0.2 as compared to USNO-B1 stars.
GCN Circular #21383
M. Stanbro and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 23:03:19.43 UT on 28 July 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170728B (trigger 522975804 / 170728961) which was also detected by the Swift/BAT (S. B. Cenko et al. 2017, GCN 21371) and Fermi LAT (M. Yassine et al. 2017, GCN 21380). The GBM on-ground location is consistent with the Swift position.
The Swift/BAT reported a short GRB in GCN 21371. Fermi GBM sees the initial short peak at trigger time but is followed up by several peaks up the ~50s later.
The trigger resulted in an Autonomous Repoint Request (ARR) by the GBM Flight Software owing to the high peak flux of the GRB. This ARR was accepted and the spacecraft slewed to the GBM in-flight location. The initial angle from the Fermi LAT boresight to the best location is 30 degrees.
The GBM light curve consists of several episodes with a duration (T90) of about 46 s (50-300 keV). The time-averaged spectrum from T0-.90 s to T0+47.23 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.10 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 175 +/- 26 keV
The event fluence (10-1000 keV) in this time interval is (4.59 +/- 0.34)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.13 s in the 10-1000 keV band is 12.7 +/- 0.32 ph/s/cm^2.
A Band function fits the spectrum equally well with Epeak= 124 +/- 30 keV, alpha = -0.93 +/- 0.19 and beta = -2.12 +/- 0.22.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #21384
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), S. B. Cenko (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-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170728B (trigger #765130) (Cenko et al., GCN Circ. 21371). The BAT ground-calculated position is RA, Dec = 238.019, 70.111 deg which is
```
  RA(J2000)  =  15h 52m 04.5s
  Dec(J2000) = +70d 06' 40.0"
```
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 5%.
The mask-weighted light curve shows a short multi-peaked structure from ~T-0.1 s to ~T+0.7 s, followed by some weak emission till ~T+50 s, Fermi/GBM also reports emission till ~T+47 s (Stanbro et al., GCN Circ. 21383). T90 (15-350 keV) is 47.7 +- 25.2 sec (estimated error including systematics).
The time-averaged spectrum for the short pulse from T-0.1 to T+0.7 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -1.10 +- 1.71, and Epeak of 82.0 +- 24.2 keV (chi squared 51.71 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 6.2 +- 1.1 x 10^-7 erg/cm2. A fit to a simple power law gives a photon index of 1.21 +- 0.24 (chi squared 61.25 for 57 d.o.f.).
The time-averaged spectrum for the extended emission from T+0.7 to T+50.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.25 +- 0.57. The fluence in the 15-150 keV band is 9.8 +- 3.9 x 10^-7 erg/cm2.
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/765130/BA/
GCN Circular #21387
Y. Kitaoka, T. Sakamoto (AGU)
We observed the field of GRB 170728B detected by Swift (Cenko et al., GCN Circ. 21371) with the iTelescope.Net (http://www.itelescope.net) T16 (Takahashi TOA-150) telescope located at the AstroCamp Observatory (Nerpio, Spain). 20 images of 60 sec exposures were taken in the R filter starting from July 28 23:03:19 (UT) about 36 mimute after the trigger and stopped on July 29 00:17:48 (UT). We do not detect the optical afterglow both in the individual images and the stacked image at the X-ray afterglow position. The estimated five sigma upper limit of the combined image (total exposure of 1200 sec) is ~15.8 using the USNO-B1 catalog.
GCN Circular #21388
GRB 170728B: Swift/UVOT Upper Limits
S. J. Laporte (PSU) and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170728B 473 s after the BAT trigger (Cenko et al., GCN Circ. 21371). No optical afterglow consistent with the optical position (D'Avanzo et al. GCN Circ. 21373) 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           473          623          147         >19.8
white              473         7867          908         >20.8
v                  630         8278          627         >19.6
b                  728        14417         1117         >21.3
u                  703        13868         1276         >21.2
w1                 679        19251         2000         >21.6
m2                6847        18681         1279         >22.1
w2                6437         8073          393         >21.5
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #21389
Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Carlos Rom=C3=A1n-Z=C3=BA=C3=B1iga (UNAM), and William H. Lee (UNAM) report:
We observed the field of the short GRB 170728B (Cenko et al., GCN Circ. 21371) with the COATLI 50-cm telescope and interim imager (Watson et al. 2016, Proc. SPIE, 9908, 50) at the Observatorio Astron=C3=B3mico Nacional on the Sierra de San Pedro M=C3=A1rtir from 2017-07-29 04:21 to 08:19 obtaining a total of 2.76 hours of observation in the clear filter.
We detect the source reported by D=E2=80=99Avanzo et al. (GCN Circ. 21372). Calibrating with respect to the USNO-B1 catalog, we estimate a preliminary magnitude of
R =3D 22.40 +/- 0.16.
This magnitude is in the USNO-B1 Vega system and is corrected for Galactic extinction in the direction of the GRB.
The source has faded by around two magnitudes between the observations in the first hour or so (D=E2=80=99Avanzo et al., GCN Circ. 21372; Heintz et al, GCN Circ. 21374; and Guidorzi et al., GCN Circ. 21375) and our observations. This confirms that the source is the optical transient associated with the GRB.
We thank the COATLI technical team (Fernando =C3=81ngeles, Oscar Chapa, Salvador Cuevas, Alejandro Farah, Jorge Fuentes, Rosal=C3=ADa Langarica, Fernando Quir=C3=B3s, and Carlos Tejada) and the staff of the Observatorio Astron=C3=B3mico Nacional.
GCN Circular #21391
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA), National University of San Juan, Argentina
H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina
O.Gres, K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, Irkutsk State University
V.Yurkov, Yu.Sergienko Blagoveschensk Educational State University, Blagoveschensk
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in IAC was pointed to the GRB170728B (Cenko et al., GCN Circ. #21371) 28 sec after notice time and 39 sec after trigger time at 2017-07-28 23:04:01 UT. On our first (10s exposure) set we found optical transient within SWIFT XRT error-box ( D'Elia et al., GCN #21376; ) in two polarizations! The 5-sigma upper limit has been about 16.9 mag We 100% found faiding OT on first 10 minutes images with m ~ 16.5 up to 18 mag.
```
RA, DEC  = 15h 51m 55s.5 , +70d 7m 19s.3
Error = +- 1.4 arcsec
```
The faiding OT may be coincide with D'Avanzo et al. position (GCN #21372) and Heintz et al., (GCN #21374) and Izzo et al., (GCN #21381) and
The observations made on zenit distance = 47 degrees, galaxy latitude b = 40 degree. The moon (34 % bright part) is 8 degrees above the horizon. The distance between moon and object is 78 The sun altitude is -33.7 degree. The error box can be observed till sunrise at 2017-07-29 06:25:17.
The message may be cited.
GCN Circular #21393
A. J. Castro-Tirado (IAA-CSIC Granada & ISA-UMA M=E1laga), A.=20 Gonz=E1lez-Rodr=EDguez, Y. Hu, R. Cunniffe, J. C. Tello, B.-B. Zhang=20 (IAA-CSIC Granada), A. Castell=F3n, I. Carrasco (UMA M=E1laga), M. Jel=ED= nek=20 (ASU-CAS Ondrejov), S. Guziy (Nikolaev Univ.), S. B. Pandey (ARIES=20 Nainital), S. Jeong (SKKU Seoul), M. D. Caballero-Garc=EDa (ASU-CAS=20 Prague), M. Wildi (Vermes Obs.) and P. Kub=E1nek (IP-ASCR Prague), on=20 behalf of a larger collaboration, report:
Following the detection of GRB 170728B by Swift (Cenko et al. GCNC=20 21371), the TELMA 0.6m robotic telescope at the BOOTES-2 astronomical=20 station at IHSM/UMA-CSIC in M=E1laga (Spain) pointed to the GRB location=20 26 sec after the notice time and 40 sec after trigger time, i.e. at=20 23:03:59 UT on July 2.
The first exposures (3 sec, unfiltered) were taken simultaneously to the=20 extended gamma-ray emission phase (Stanbro et al. GCNC 21383, Ukwatta et=20 al. GCNC 21384), confirming the optical transient within the Swift/XRT=20 error box (D'Elia et al., GCNC 21376) being coincident with the optical=20 afterglow position (D'Avanzo et al. GCN 21373) with magnitudes in the=20 range reported by Lipunov et al. (GCNC et al. 21391) starting 2 sec=20 after. A detailed analysis is ongoing.
This message can be quoted.
GCN Circular #21394
B. Dintinjana and H. Mikuz on behalf of PIKA observing program at Crni Vrh Observatory:
We observed the afterglow of GRB 170728B (Cenko et al., GCN Circ. 21371) with 60 cm Cichocki robotic telescope at Crni Vrh Observatory, Slovenia. The series of twenty-six 60 second exposures with Rc filter started at 23:04:41UT, 81 seconds after the burst. We confirm optical afterglow at coordinates reported by D=92Avanzo et al. (GCN Circ. 21372, 21373).
Photometry results are given in table below. The table contains the mid time of exposure in MJD, time since the Swift GRB detection to the middle of exposure in seconds, Rc magnitude and photometric error. The magnitudes are derived using comparison stars from the APASS catalog. The 3-sigma limiting magnitude in Rc filter is around magnitude 20.2 =B1 0.2. The light curve of the GRB 170728B: http://www.observatorij.org/vstars/GRB170728B/GRB170728B.png
```
MJD t-T0 Rc err
(s) (mag) (mag)
-------------------------------------
57962.961574 81 17.410 0.04
57962.962407 153 17.867 0.05
57962.963252 226 18.077 0.06
57962.964097 299 18.412 0.08
57962.964931 371 18.638 0.10
57962.965775 444 18.830 0.11
57962.966620 517 18.827 0.11
57962.967454 589 19.123 0.14
57962.968299 662 19.054 0.13
57962.969144 735 19.142 0.14
57962.969977 807 19.181 0.15
57962.970822 880 19.217 0.16
57962.971667 953 19.714 0.26
57962.972512 1026 19.505 0.22
57962.973345 1098 19.507 0.20
57962.974190 1171 19.586 0.23
57962.975023 1243 19.674 0.27
57962.975868 1316 19.456 0.23
57962.976713 1389 19.981 0.35
57962.977558 1462 19.734 0.25
57962.978391 1534 20.227 0.42
57962.979236 1607 19.736 0.25
57962.980081 1680 19.878 0.32
57962.980926 1753 20.200 0.38
57962.981759 1825 19.519 0.21
57962.982604 1898 19.913 0.31
-------------------------------------
```
GCN Circular #21395
W. Fong (University of Arizona), T. Laskar (NRAO/UC Berkeley), K. D. Alexander (Harvard) and E. Berger (Harvard) report:
"We observed the position of GRB 170728B (Cenko et al., GCN 21371; Yassine et al., GCN 21380; Stanbro & Meegan, GCN 21383) with the Karl G. Jansky Very Large Array (VLA) beginning on 2017 Jul 29.075 UT (2.75 hr post-burst) at a mean frequency of 6 GHz. We obtained a second set of observations beginning on 2017 Jul 29.811 UT (20.4 hr post-burst) at mean frequencies of 6 and 10 GHz.
We do not detect any radio counterpart in our first set of observations at 2.75 hr, while we clearly detect a radio source in our second set of observations at both frequencies at 20.4 hr at the position:
```
RA(J2000) = 15:51:55.45
Dec(J2000) = +70:07:21.2
```
with an uncertainty of 0.2" in each coordinate. This position is coincident with the reported optical source (D'Avanzo et al., GCN 21372, GCN 21373; Heintz et al., GCN 21374; Guidorzi et al., GCN 21375; Watson et al., GCN 21389). Given the rapid variability and positional coincidence with the X-ray (Osborne et al., GCN 21377) and optical afterglows, we consider this to be the radio afterglow of GRB 170728B.
Further observations are planned. We thank the VLA staff for quickly executing these observations."
GCN Circular #21398
A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 170728B (Swift-BAT trigger 765130: Cenko et al., GCN 21371; Ukwatta et al., GCN 21384; Fermi-LAT detection: Yassine et al., GCN 21380; Fermi-GBM observation: Stanbro et al., GCN 21383) triggered Konus-Wind at T0=82998.412 s UT (23:03:18.412).
The burst light curve shows an initial short multi-peaked structure with a duration of ~0.5 s, followed by a weaker emission seen up to ~48 s. The emission is seen up to ~2 MeV.
As observed by Konus-Wind, the burst had a fluence of 3.96(-0.75,+0.93)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0-0.016 s, of 4.38(-0.91,+0.93)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.13(-0.37,+0.45) and Ep = 160(-43,+103) keV (chi2 = 66/62 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.1 (chi2 = 66/61 dof)
The spectrum near the maximum count rate (measured from T0+0.000 to T0+0.256 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model with alpha = -0.22(-0.33,+0.39) and Ep = 166(-22,+26) keV (chi2 = 22/36 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.0 (chi2 = 22/35 dof)
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB170728_T82998/
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #21399
GRB 170728B: Swift/UVOT Detection
S. J. LaPorte (PSU), S.W.K. Emery (MSSL), and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team:
After detailed analysis of initial data reported in LaPorte and Cenko, GCN Circ. 21388, we do find a significant detection in initial optical filter exposures.
The Swift/UVOT began settled observations of the field of GRB 170728B 473 s after the BAT trigger (Cenko et al., GCN Circ. 21371). A fading source consistent with the optical position (D'Avanzo et al. GCN Circ. 21373) is detected in the initial UVOT exposures.
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              876         1026          147         20.56 +/- 0.20
v                  630         8278          627         20.23 +/- 0.27
b                  728         2561          194         20.60 +/- 0.29
u                  703        13868         1276        >21.2
w1                 679        19251         2000        >21.6
m2                6847        18681         1279        >22.1
w2                6437         8073          393        >21.5
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #21401
N.Tyurina, V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA), National University of San Juan, Argentina
H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina
O.Gres, K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, Irkutsk State University
V.Yurkov, Yu.Sergienko Blagoveschensk Educational State University, Blagoveschensk
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
We found additional image in MASTER-IAC DataBase with more early time. So the begining of our GCN Circular #21391 must be readed as:
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in IAC was pointed to the GRB170728B 19 sec after notice time and 30 sec after trigger time at 2017-07-28 23:03:49 UT. On our first (10s exposure) image we found optical transient within SWIFT error-box (Cenko et al., GCN Circ. #21371). The 5-sigma upper limit has been about 16.6 mag
The message may be cited.
GCN Circular #21419
A. Volnova (IKI), A. Kusakin (Fesenkov Astrophysical Institute), A.S. Moskvitin (SAO RAS), O.I. Spiridonova (SAO RAS), R. Inasaridze (AbAO), I. Reva (Fesenkov Astrophysical Institute), E. Mazaeva (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 170728B (Cenko et al., GCN 21371) with Zeiss-1000 of SAO RAS (July 29, August 4,5 ), AS-32 telescope of AbAO (July 29) and Zeiss-1000 telescope of Tien Shan Astronomical Observatory (July 30,31 August 1,6). Below we report the photometry of the optical afterglow (D'Avanzo et al., GCNs 21372, 21373; Heintz et al., GCN 21374; Guidorzi et al., GCN 21375) and upper limits of our observations. Preliminary photometry is following:
```
Date       UT start   t-T0    Filter Exp. OT     Err. UL  Telescope
                       (mid, days)     (s)             (3 sigma)

2017-07-29 00:41:51  0.07228  R    600   n/d     n/d  18.6  Z-1000 SAO
2017-07-29 17:27:49  0.79594 CR   43*60  n/d     n/d  20.4  AS-32  AbAO
2017-07-30 16:12:56  1.79815  R  97*120   21.93  0.25  22.1  Z-1000 TSHAO
2017-08-01 15:12:51  3.72304  R  60*120  n/d     n/d  21.6  Z-1000 TSHAO
2017-08-04 00:41:51  5.98081  R  41*300   22.6  0.23  22.8  Z-1000 SAO
```
The photometry is based on nearby USNO-B1.0 stars
1601-0108291 15:52:31.54 +70:09:31.7 R2 17.95
1601-0108289 15:52:28.99 +70:09:26.3 R2 18.08
1601-0108260 15:51:57.87 +70:09:53.8 R2 16.87
1601-0108254 15:51:50.88 +70:08:41.2 R2 15.04
1601-0108262 15:52:03.24 +70:07:32.0 R2 16.01
Coordinates of the afterglow obtained from observation on July 30 are (J2000) 15 51 55.5179 +70 07 21.123 with uncertainties on both coordinates of 0.2 arces which is compatible with coordinates of TNG (D'Avanzo et al., GCN 21373) and VLA (Fong et al., GCN 21395). The finding chart can be found in http://grb.rssi.ru/GRB170728B/GRB170728B_TShAO_R_170730.png
The light curve of the afterglow based on observations above and photometry reported in GCNs (Dintinjana et al., GCN 21394; Watson GCN 21389; D'Avanzo et al., GCN 21372; Heintz et al., GCN 21374; Guidorzi et al., GCN 21375) can be found in http://grb.rssi.ru/GRB170728B/GRB170728B_lc+GCNs_v2.png Based on our observation on July, 30 (~ 1.8 days after burst onset) one can suggest that the OT experienced rebrightening at that epoch.
GCN Circular #21441
Poonam Chandra & A. J. Nayana (NCRA-TIFR, India) report:
We observed the short hard burst GRB 170728B (Cenko et al., GCN Circ. 213= 71) with the Giant Metre Wave Radio Telescope (GMRT) at 1390 MHz band on = 2017 August 09.61 UT, i.e. 11.65 days after the burst. We do not see any = significant radio emission at the burst position (D=E2=80=99Avanzo et al.= GCN Circ. 21373). The 3-sigma upper limit on the GRB radio flux density = is 140 uJy.
We thank the GMRT staff for scheduling these observations.=20
GCN Circular #21466
K. P. Mooley (Hintze Fellow, Oxford), T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester)
The AMI Large Array robotically triggered on the Swift alert for the short GRB 170728B (Cenko et al., GCN 21371) as part of the 4pisky program, and subsequent follow up observations were obtained up to 3 days post-burst. Our observations at 15 GHz on 2017 Jul 29.00, Jul 29.80, Jul 30.80 and Jul 31.76 (UT) do not reveal any radio source at the XRT location (Osborne et al., GCN 21377), with 3sigma upper limits of 258 uJy, 201 uJy, 171 uJy and 108 uJy respectively. This upper limit is consistent with the radio afterglow detection on 2017 Jul 29.81 reported by Fong et al. (GCN 21395; much fainter than 300 uJy at 6 GHz).
We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.
Redshift z= 1.272 +- 0.002 from host galaxy emission ([OII])
W.-F. Fong et al. 2022, ApJ 940, 56

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