Gamma-ray Burst 150527A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 27 May 15 06:49:10 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     641698,   Seg_Num: 0
GRB_RA:          288.958d {+19h 15m 50s} (J2000),
                 289.149d {+19h 16m 36s} (current),
                 288.336d {+19h 13m 21s} (1950)
GRB_DEC:          +4.194d {+04d 11' 38"} (J2000),
                  +4.222d {+04d 13' 19"} (current),
                  +4.105d {+04d 06' 18"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2763 [cnts]    Image_Peak=175 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   124     E_range: 25-100 keV
BKG_INTEN:       31560 [cnts]
BKG_TIME:        24522.36 SOD {06:48:42.36} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17169 TJD;   147 DOY;   15/05/27
GRB_TIME:        24535.80 SOD {06:48:55.80} UT
GRB_PHI:         -91.77 [deg]
GRB_THETA:        10.26 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     16.03 [sigma]
IMAGE_SIGNIF:    9.07 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +2  +0  +0  +1 +62  +0 
SUN_POSTN:        63.79d {+04h 15m 09s}  +21.25d {+21d 15' 08"}
SUN_DIST:        128.78 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.71d {+11h 30m 51s}   +1.58d {+01d 34' 59"}
MOON_DIST:       116.22 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.46, -3.49 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      291.18, 26.25 [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 = 355.32,-1.13 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 27 May 15 06:47:33 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      46
TRIGGER_NUM:     454402031
GRB_RA:          286.550d {+19h 06m 12s} (J2000),
                 286.739d {+19h 06m 57s} (current),
                 285.936d {+19h 03m 45s} (1950)
GRB_DEC:          +5.700d {+05d 42' 00"} (J2000),
                  +5.725d {+05d 43' 28"} (current),
                  +5.622d {+05d 37' 20"} (1950)
GRB_ERROR:       12.82 [deg radius, statistical plus systematic]
GRB_INTEN:       121 [cnts/sec]
DATA_SIGNIF:     6.00 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        17169 TJD;   147 DOY;   15/05/27
GRB_TIME:        24428.70 SOD {06:47:08.70} UT
GRB_PHI:         175.00 [deg]
GRB_THETA:        90.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.19
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      82%  GRB
2nd_MOST_LIKELY:  13%  Cyg X-1
DETECTORS:       0,0,0, 0,0,0, 0,0,1, 0,1,1, 0,0,
SUN_POSTN:        63.79d {+04h 15m 09s}  +21.25d {+21d 15' 07"}
SUN_DIST:        129.99 [deg]   Sun_angle= 9.1 [hr] (West of Sun)
MOON_POSTN:      172.70d {+11h 30m 48s}   +1.59d {+01d 35' 14"}
MOON_DIST:       113.73 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.69, -0.67 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      288.74, 28.07 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2015/bn150527283/quicklook/glg_lc_medres34_bn150527283.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 49.95,-17.57 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 27 May 15 06:48:03 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     454402031
GRB_RA:          294.320d {+19h 37m 17s} (J2000),
                 294.511d {+19h 38m 03s} (current),
                 293.699d {+19h 34m 48s} (1950)
GRB_DEC:          +4.430d {+04d 25' 48"} (J2000),
                  +4.465d {+04d 27' 56"} (current),
                  +4.317d {+04d 19' 00"} (1950)
GRB_ERROR:       7.15 [deg radius, statistical only]
DATA_SIGNIF:     10.70 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        17169 TJD;   147 DOY;   15/05/27
GRB_TIME:        24428.70 SOD {06:47:08.70} UT
GRB_PHI:         180.00 [deg]
GRB_THETA:        84.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:        63.79d {+04h 15m 09s}  +21.25d {+21d 15' 07"}
SUN_DIST:        124.06 [deg]   Sun_angle= 8.6 [hr] (West of Sun)
MOON_POSTN:      172.70d {+11h 30m 49s}   +1.59d {+01d 35' 10"}
MOON_DIST:       121.54 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       42.18, -8.11 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      297.09, 25.61 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2015/bn150527283/quicklook/glg_lc_medres34_bn150527283.gif
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.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 27 May 15 06:50:07 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     641698,   Seg_Num: 0
POINT_RA:        288.948d {+19h 15m 48s} (J2000)
POINT_DEC:        +4.182d {+04d 10' 57"} (J2000)
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24597.63 SOD {06:49:57.63} UT,   61.8 [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:     Wed 27 May 15 06:52:33 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     641698,   Seg_Num: 0
GRB_RA:          288.958d {+19h 15m 50s} (J2000),
                 289.149d {+19h 16m 36s} (current),
                 288.336d {+19h 13m 21s} (1950)
GRB_DEC:          +4.194d {+04d 11' 38"} (J2000),
                  +4.222d {+04d 13' 19"} (current),
                  +4.105d {+04d 06' 18"} (1950)
GRB_DATE:        17169 TJD;   147 DOY;   15/05/27
GRB_TIME:        24535.80 SOD {06:48:55.80} UT
TRIGGER_INDEX:   124
GRB_PHI:         -91.77 [deg]
GRB_THETA:        10.26 [deg]
DELTA_TIME:      -63.00 [sec]
TRIGGER_DUR:     0.512 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     16.03 [sigma]
IMAGE_SIGNIF:    9.07 [sigma]
LC_URL:          sw00641698000msb.lc
SUN_POSTN:        63.79d {+04h 15m 10s}  +21.25d {+21d 15' 09"}
SUN_DIST:        128.79 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.74d {+11h 30m 57s}   +1.57d {+01d 34' 28"}
MOON_DIST:       116.19 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.46, -3.49 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      291.18, 26.25 [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 = 355.32,-1.13 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 27 May 15 06:53:57 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     641698,   Seg_Num: 0
GRB_RA:          288.9598d {+19h 15m 50.35s} (J2000),
                 289.1511d {+19h 16m 36.27s} (current),
                 288.3384d {+19h 13m 21.22s} (1950)
GRB_DEC:          +4.2003d {+04d 12' 01.0"} (J2000),
                  +4.2283d {+04d 13' 41.8"} (current),
                  +4.1113d {+04d 06' 40.5"} (1950)
GRB_ERROR:       3.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24618.00 SOD {06:50:18.00} UT,   82.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        63.79d {+04h 15m 10s}  +21.25d {+21d 15' 10"}
SUN_DIST:        128.78 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.75d {+11h 31m 00s}   +1.57d {+01d 34' 15"}
MOON_DIST:       116.19 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.46, -3.49 [deg] galactic lon,lat of the burst
ECL_COORDS:      291.18, 26.26 [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:     Wed 27 May 15 06:54:03 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     641698,   Seg_Num: 0
POINT_RA:        288.948d {+19h 15m 48s} (J2000)
POINT_DEC:        +4.182d {+04d 10' 56"} (J2000)
POINT_ROLL:      58.206d
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24603.62 SOD {06:50:03.62} UT,   67.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.760
N_STARS:         190
X_OFFSET:        566 [pixels]
Y_OFFSET:        462 [pixels]
X_MAX:           1525 [pixels]
Y_MAX:           1421 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00641698000msufc0067.fits
SUN_POSTN:        63.79d {+04h 15m 10s}  +21.25d {+21d 15' 10"}
SUN_DIST:        128.80 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.75d {+11h 31m 00s}   +1.57d {+01d 34' 14"}
MOON_DIST:       116.17 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.44, -3.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      291.16, 26.24 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 27 May 15 06:54:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     641698,   Seg_Num: 0
POINT_RA:        288.948d {+19h 15m 48s} (J2000)
POINT_DEC:        +4.182d {+04d 10' 56"} (J2000)
POINT_ROLL:      58.206d
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24603.62 SOD {06:50:03.62} UT,   67.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.760
N_STARS:         190
X_OFFSET:        566 [pixels]
Y_OFFSET:        462 [pixels]
X_MAX:           1525 [pixels]
Y_MAX:           1421 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00641698000msufc0067.fits
SUN_POSTN:        63.79d {+04h 15m 10s}  +21.25d {+21d 15' 10"}
SUN_DIST:        128.80 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.75d {+11h 31m 01s}   +1.57d {+01d 34' 09"}
MOON_DIST:       116.17 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.44, -3.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      291.16, 26.24 [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:     Wed 27 May 15 06:55:35 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     641698,   Seg_Num: 0
POINT_RA:        288.948d {+19h 15m 48s} (J2000)
POINT_DEC:        +4.182d {+04d 10' 56"} (J2000)
ROLL:            58.206d
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24603.62 SOD {06:50:03.62} UT,   67.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     454402217
X_OFFSET:        885 [pixels]
Y_OFFSET:        781 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1045
Y_GRB_POS:       941
BINNING_INDEX:   1
IM_URL:          sw00641698000msuni0081.fits
SUN_POSTN:        63.79d {+04h 15m 10s}  +21.25d {+21d 15' 10"}
SUN_DIST:        128.80 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.76d {+11h 31m 03s}   +1.57d {+01d 33' 59"}
MOON_DIST:       116.16 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.44, -3.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      291.16, 26.24 [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:     Wed 27 May 15 06:55:59 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     641698,   Seg_Num: 0
POINT_RA:        288.948d {+19h 15m 48s} (J2000)
POINT_DEC:        +4.182d {+04d 10' 56"} (J2000)
ROLL:            58.206d
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24603.62 SOD {06:50:03.62} UT,   67.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     454402217
X_OFFSET:        885 [pixels]
Y_OFFSET:        781 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1045
Y_GRB_POS:       941
BINNING_INDEX:   1
IM_URL:          sw00641698000msuni0081.fits
SUN_POSTN:        63.79d {+04h 15m 10s}  +21.25d {+21d 15' 11"}
SUN_DIST:        128.80 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.76d {+11h 31m 03s}   +1.57d {+01d 33' 56"}
MOON_DIST:       116.16 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.44, -3.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      291.16, 26.24 [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:     Wed 27 May 15 07:01:37 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     641698,   Seg_Num: 0
POINT_RA:        288.946d {+19h 15m 47s} (J2000)
POINT_DEC:        +4.181d {+04d 10' 50"} (J2000)
POINT_ROLL:      58.205d
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24815.72 SOD {06:53:35.72} UT,   279.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        2.568
N_STARS:         190
X_OFFSET:        326 [pixels]
Y_OFFSET:        222 [pixels]
X_MAX:           1765 [pixels]
Y_MAX:           1661 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00641698000msufc0279.fits
SUN_POSTN:        63.80d {+04h 15m 11s}  +21.25d {+21d 15' 13"}
SUN_DIST:        128.81 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.81d {+11h 31m 14s}   +1.55d {+01d 33' 03"}
MOON_DIST:       116.12 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.44, -3.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      291.16, 26.24 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 27 May 15 07:02:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     641698,   Seg_Num: 0
POINT_RA:        288.946d {+19h 15m 47s} (J2000)
POINT_DEC:        +4.181d {+04d 10' 50"} (J2000)
POINT_ROLL:      58.205d
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24815.72 SOD {06:53:35.72} UT,   279.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        2.568
N_STARS:         190
X_OFFSET:        326 [pixels]
Y_OFFSET:        222 [pixels]
X_MAX:           1765 [pixels]
Y_MAX:           1661 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00641698000msufc0279.fits
SUN_POSTN:        63.80d {+04h 15m 12s}  +21.25d {+21d 15' 13"}
SUN_DIST:        128.81 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.81d {+11h 31m 15s}   +1.55d {+01d 32' 58"}
MOON_DIST:       116.11 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.44, -3.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      291.16, 26.24 [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:     Wed 27 May 15 07:02:48 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     641698,   Seg_Num: 0
GRB_RA:          288.9599d {+19h 15m 50.37s} (J2000),
                 289.1512d {+19h 16m 36.29s} (current),
                 288.3386d {+19h 13m 21.25s} (1950)
GRB_DEC:          +4.2012d {+04d 12' 04.3"} (J2000),
                  +4.2292d {+04d 13' 45.0"} (current),
                  +4.1122d {+04d 06' 43.8"} (1950)
GRB_ERROR:       2.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24618.00 SOD {06:50:18.00} UT,   82.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        63.80d {+04h 15m 12s}  +21.25d {+21d 15' 13"}
SUN_DIST:        128.79 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.82d {+11h 31m 16s}   +1.55d {+01d 32' 52"}
MOON_DIST:       116.12 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.46, -3.49 [deg] galactic lon,lat of the burst
ECL_COORDS:      291.18, 26.26 [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:     Wed 27 May 15 07:03:10 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     641698,   Seg_Num: 0
POINT_RA:        288.946d {+19h 15m 47s} (J2000)
POINT_DEC:        +4.181d {+04d 10' 50"} (J2000)
ROLL:            58.205d
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24815.72 SOD {06:53:35.72} UT,   279.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     454402429
X_OFFSET:        885 [pixels]
Y_OFFSET:        781 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1045
Y_GRB_POS:       941
BINNING_INDEX:   1
IM_URL:          sw00641698000msuni0293.fits
SUN_POSTN:        63.80d {+04h 15m 12s}  +21.25d {+21d 15' 14"}
SUN_DIST:        128.81 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.82d {+11h 31m 17s}   +1.55d {+01d 32' 49"}
MOON_DIST:       116.10 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.44, -3.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      291.16, 26.24 [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:     Wed 27 May 15 07:03:20 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     641698,   Seg_Num: 0
POINT_RA:        288.946d {+19h 15m 47s} (J2000)
POINT_DEC:        +4.181d {+04d 10' 50"} (J2000)
ROLL:            58.205d
IMG_START_DATE:  17169 TJD;   147 DOY;   15/05/27
IMG_START_TIME:  24815.72 SOD {06:53:35.72} UT,   279.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     454402429
X_OFFSET:        885 [pixels]
Y_OFFSET:        781 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1045
Y_GRB_POS:       941
BINNING_INDEX:   1
IM_URL:          sw00641698000msuni0293.fits
SUN_POSTN:        63.80d {+04h 15m 12s}  +21.25d {+21d 15' 14"}
SUN_DIST:        128.81 [deg]   Sun_angle= 9.0 [hr] (West of Sun)
MOON_POSTN:      172.82d {+11h 31m 17s}   +1.55d {+01d 32' 47"}
MOON_DIST:       116.10 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       39.44, -3.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      291.16, 26.24 [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 #17874
P. A. Evans (U Leicester), S. D. Barthelmy (GSFC), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester) and T. N. Ukwatta (LANL) report on behalf of the Swift Team:
At 06:48:55 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150527A (trigger=641698). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 288.958, +4.194 which is
```
   RA(J2000) = 19h 15m 50s
   Dec(J2000) = +04d 11' 38"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 40 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 06:49:57.6 UT, 61.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 288.9599, 4.2013 which is equivalent to:
```
   RA(J2000)  = 19h 15m 50.39s
   Dec(J2000) = +04d 12' 04.7"
```
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This location is 27 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 5.67 x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 67 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the large, but uncertain extinction expected.
Burst Advocate for this burst is P. A. Evans (pae9 AT star.le.ac.uk). 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 #17876
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC),= and Harvey Moseley (GSFC) report:
We observed the field of GRB 150527A (Evans, et al., GCN 17874) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional = on Sierra San Pedro M=E1rtir from 2015/05 27.29 to 2015/05 27.32 UTC (13.2 t= o 54.6 minutes after the BAT trigger), obtaining a total of 0.58 hours exposure in the r, i, and z bands.
A source is detected within the Swift-XRT error circle. In comparison wi= th the USNO-B1 catalog, we obtain the following detections and upper limit (3-sigma):
```
  r     21.17 +/- 0.10
  i     20.83 +/- 0.14
  z     > 19.50
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Additional observations are ongoing.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #17877
J. Japelj (U. Ljubljana), C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath), S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of a larger collaboration report:
The 1-m LCOGT McDonald unit began observing Swift GRB 150527A (Evans al GCN 17874) on May 27 at 06:56:33 UT (~7.6 minutes after the burst trigger) with SDSS r and i filters. Inside the Swift-XRT error circle we provide conservative limits on detection down to the following limiting magnitudes:
```
Mid Time      Exposure       Filter       Magnitude
(s)           (s)
---------------------------------------------------
  795          5x120          r'           > 19.5
1500          5x120          i'           > 18.3
---------------------------------------------------
```
These values are compatible with the source reported by RATIR (Butler et al. GCN 17876), although no information about its position is reported. We note the presence of a faint source in our coadded image with i'=20.6 +- 0.4 mag at the following position: RA(J2000)=19:15:50.31, Dec(J2000)= +04:12:05.0. However, we caution that the field is crowded, Galactic dust extinction towards this field is high, A_V = 2.7 mag (Schlafly et al. 2011). Calibration is done against nearby USNOB-1 stars.
GCN Circular #17878
H.-F. Yu (MPE) reports on behalf of the Fermi GBM Team:
"At 06:47:08.70 UT on 27 May 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150527A (trigger 454402031 / 150527283), which was also detected by Swift (Evans et al. 2015, GCN 17874). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 89 degrees.
The GBM light curve shows one single pulse with a duration (T90) of about 9.2 s (50-300 keV). The time-averaged spectrum from T0-3.072 s to T0+7.168 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.76 +/- 0.20 and the cutoff energy, parameterized as Epeak, is 319 +/- 97 keV.
The event fluence (10-1000 keV) in this time interval is (2.2 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+2.304 s in the 10-1000 keV band is 2.1 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #17879
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 2996 s of XRT Photon Counting mode data and 4 UVOT images for GRB 150527A, 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 = 288.95986, +4.20196 which is equivalent to:
```
RA (J2000): 19h 15m 50.37s
Dec (J2000): +04d 12' 07.0"
```
with an uncertainty of 1.6 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 #17880
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), P. A. Evans (U Leicester), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+711 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150527A (trigger #641698) (Evans, et al., GCN Circ. 17874). The BAT ground-calculated position is RA, Dec = 288.962, 4.195 deg, which is
```
   RA(J2000)  =  19h 15m 50.9s 
   Dec(J2000) = +04d 11' 41.0" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 99%.
The mask-weighted light curves shows a multi-peak event starting at ~T-45 sec, with the brightest peak at ~T-14, and ending at T+25 sec. T90 (15-350 keV) is 112 +- 80 sec (estimated error including systematics).
The time-averaged spectrum from T-111.44 to T+16.56 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.69 +- 0.10. The fluence in the 15-150 keV band is 3.1 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-7.94 sec in the 15-150 keV band is 0.3 +- 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/641698/BA/
GCN Circular #17881
L. Nicastro, E. Palazzi, A. Rossi (INAF/IASF Bologna), D. Fugazza (INAF/OAB) on behalf of the REM team:
We observed the field of the GRB150527A (Evans et al., GCN 17874) simultaneously in the optical (griz) and near infrared (H) bands with the 60-cm robotic telescope REM at La Silla Observatory (Chile). The observations started about 1 min after the GRB trigger.
An uncatalogued source in the enhanced XRT error box (Evans et al., GCN 17879) is detectedi, only in the H images, at the coordinates:
```
RA(J2000) = 19:15:50.31
DEC(J2000) = +04:12:06.1
```
Possibly this is the same source mentioned by Butler et al. (GCN 17876).
A very preliminary photometry, calibrated against 2MASS, indicates that the object faded from H = 14.8 +/- 0.2 in the first image to H = 15.2 +/- 0.2 about 5 min later. Thus we identify this source as the NIR afterglow of the burst.
GCN Circular #17882
A. A. Breeveld (UCL-MSSL) and P. A. Evans (U. Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150527A 68 s after the BAT trigger (Evans et al., GCN Circ. 17874). No optical afterglow consistent with the enhanced XRT position (Evans et al. GCN Circ. 17879) or with the RATIR or REM sources (Butler et al., GCN Circ. 17876 and Nicastro et al., GCN Circ. 17881) 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            68          218          147         >20.2
u_FC               280          523          240         >19.1
white            10385        11927         1542         >21.2
v                 4315         4515          197         >18.8
b                 3700        10380         1082         >20.8
u                  280         6271          623         >19.6
w1                5920         6120          197         >19.4
w2                4110        12019          281         >19.8
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.97 in the direction of the burst (Schlegel et al. 1998). We note however that the value for extinction could be unreliable at this position.
GCN Circular #17883
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME and OISTER collaboration:
We observed the field of GRB 150527A (Evans et al., GCNC 17874) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2015-05-27 12:57:14 UT (~6.1 h after the burst). We could not detect the previously reported afterglow (Butler et al., GCNC 17527) in all the three bands.
Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc     Ic
-----------------------------------------------------
0.29760    13:57:27    5760.0   >19.5  >19.2  >18.3
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #17884
A. Amaral-Rogers (U. Leicester), A. D'a=EC (INAF-IASFPA), A. Maselli=20 (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 3.7 ks of XRT data for GRB 150527A (Evans et al. GCN Circ. 17874), from 47 s to 22.7 ks after the BAT trigger. The data comprise 598 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 enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 17879).
The late-time light curve (from T0+3.7 ks) can be modelled with a power-law decay with a decay index of alpha=3D0.9 (+0.6, -0.4).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.0 (+0.4, -0.3). The best-fitting absorption column is 1.2 (+0.5, -0.4) x 10^22 cm^-2, in excess of the Galactic value of 5.7 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.8 x 10^-11 (9.5 x 10^-11) erg cm^-2 count^-1.=20
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.2 (+0.5, -0.4) x 10^22 cm^-2
Galactic foreground: 5.7 x 10^21 cm^-2
Excess significance: 2.7 sigma
Photon index:	     2.0 (+0.4, -0.3)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00641698.
This circular is an official product of the Swift-XRT team.
GCN Circular #17885
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, 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 150527A (Swift-BAT trigger #641698: Evans, et al., GCN Circ. 17874; Lien, et al., GCN Circ. 17880; Fermi-GBM detection: Yu, GCN Circ.17878) was detected by Konus-Wind in the waiting mode.
The burst light curve shows two emission episodes: the first episode (from ~T0(BAT)-108 s to ~T0(BAT)-99 s) triggered GBM, and the second (from ~T0(BAT)-22 s to ~T0(BAT)+4s), which triggered BAT.
As observed by Konus-Wind, the burst had a fluence of 6.09(-0.62,+0.76)x10^-6 erg/cm2 and a 2.944-s peak flux, measured from ~T0(BAT)-13 s, of 3.10(-0.61,+0.65)x10^-7 erg/cm2/s (both in the 20 - 1000 keV energy range).
Fitting the K-W 3-channel time-integrated spectrum (measured from ~T0(BAT)-108 s to ~T0(BAT)+4 s) by a simple power-law model yields the photon index -2.20(-0.10,+0.10), chi2=0.88/1 dof.
Modelling the 3-channel spectrum near the peak count rate (from ~T0(BAT)-13 s to ~T0(BAT)-10 s) by the cutoff power law yields the following model parameters: the photon index alpha = -1.62(-0.31,+0.92), and the peak energy Ep = 107(-40,+100) keV.
All the quoted errors are estimated at the 1 sigma confidence level. All the presented results are preliminary.
The K-W light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB150527A/
GCN Circular #17898
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 150527A (Evans, et al., GCN 17874) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional = on Sierra San Pedro M=E1rtir initially from 2015/05 27.29 to 2015/05 27.45 U= TC (0.17 to 4.06 hours after the BAT trigger), obtaining a total of 3.10 hou= rs exposure in the r, i, and z bands and then again from 2015/05 28.25 to 2015/05 28.47 UTC (23.27 to 28.36 hours after the BAT trigger), obtaining a total of 3.91 hours exposure in the r, i, and z bands.
The source we initially detected (Butler, et al., GCN 17876; RA, Dec =3D 19:15:50.27, 4:12:4.7; J2000, +/-0.5") in the Swift-XRT error circle (Evans, et al., GCN 17874) has not faded in our extended dataset and is, therefore, unlikely to be the afterglow.
We note the REM source (Nicastro, et al., GCN 17881) is marginally detected in our first epoch observation with i=3D23.4 +/- 0.5, calibrated relative to the USNO-B1 catalog.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.

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Jochen Greiner, last update: 02-Jun-2015 [Disclaimer]