Gamma-ray Burst 090518

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 18 May 09 01:55:03 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     264304486
GRB_RA:          122.483d {+08h 09m 56s} (J2000),
                 122.614d {+08h 10m 27s} (current),
                 121.785d {+08h 07m 09s} (1950)
GRB_DEC:         +13.583d {+13d 34' 60"} (J2000),
                 +13.555d {+13d 33' 19"} (current),
                 +13.731d {+13d 43' 53"} (1950)
GRB_ERROR:       14.88 [deg radius, statistical plus systematic]
GRB_INTEN:       188 [cnts/sec]
DATA_SIGNIF:     9.00 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        14969 TJD;   138 DOY;   09/05/18
GRB_TIME:        6884.52 SOD {01:54:44.52} UT
GRB_PHI:         324.00 [deg]
GRB_THETA:        45.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      1.10
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,1,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        54.99d {+03h 39m 58s}  +19.55d {+19d 32' 56"}
SUN_DIST:         64.71 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      336.48d {+22h 25m 54s}   -6.78d {-06d 46' 55"}
MOON_DIST:       146.02 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      209.17, 23.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      121.69, -6.35 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 241.95,-18.07 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 18 May 09 01:55:44 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     264304486
GRB_RA:          117.420d {+07h 49m 41s} (J2000),
                 117.548d {+07h 50m 12s} (current),
                 116.737d {+07h 46m 57s} (1950)
GRB_DEC:          +9.630d {+09d 37' 48"} (J2000),
                  +9.606d {+09d 36' 21"} (current),
                  +9.757d {+09d 45' 24"} (1950)
GRB_ERROR:       9.67 [deg radius, statistical only]
DATA_SIGNIF:     9.00 [sigma]
DATA_INTERVAL:   1.024 [sec]
GRB_DATE:        14969 TJD;   138 DOY;   09/05/18
GRB_TIME:        6884.52 SOD {01:54:44.52} UT
GRB_PHI:         333.00 [deg]
GRB_THETA:        45.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:        54.99d {+03h 39m 58s}  +19.55d {+19d 32' 56"}
SUN_DIST:         61.05 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      336.48d {+22h 25m 56s}   -6.78d {-06d 46' 46"}
MOON_DIST:       141.38 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      210.78, 17.27 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      117.57,-11.22 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN/BACODINE POSITION NOTICE

TITLE:        GCN/SIMBAD_NED NOTICE
NOTICE_DATE:  Mon May 18 01:57:32 UTC 2009
NOTICE_TYPE:  Swift-BAT Position search
TRIGGER_NUM:  352420
RA:           119.9333 (J2000)
DEC:          0.7679 (J2000)
 
SIMBAD search for BAT_RA,Dec=119.9333,0.7679,radius=10.0arcmin
 
Num   RA         Dec                    Name                        Type  Num_Pub  Distance

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 01:57:24 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     352420,   Seg_Num: 0
GRB_RA:          119.933d {+07h 59m 44s} (J2000),
                 120.054d {+08h 00m 13s} (current),
                 119.289d {+07h 57m 09s} (1950)
GRB_DEC:          +0.768d {+00d 46' 04"} (J2000),
                  +0.742d {+00d 44' 30"} (current),
                  +0.905d {+00d 54' 20"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       1313 [cnts]    Image_Peak=120 [image_cnts]
TRIGGER_DUR:     0.256 [sec] 
TRIGGER_INDEX:   37     E_range: 25-100 keV
BKG_INTEN:       27477 [cnts]
BKG_TIME:        6867.24 SOD {01:54:27.24} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14969 TJD;   138 DOY;   09/05/18
GRB_TIME:        6884.27 SOD {01:54:44.27} UT
GRB_PHI:         -45.76 [deg]
GRB_THETA:        26.85 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     14.62 [sigma]
IMAGE_SIGNIF:    9.03 [sigma]
MERIT_PARAMS:     +1  +0  +0  -2  +2  -1  +0  +0 -40  +0 
SUN_POSTN:        54.99d {+03h 39m 58s}  +19.55d {+19d 32' 57"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.49d {+22h 25m 59s}   -6.77d {-06d 46' 24"}
MOON_DIST:       143.16 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.20, 15.51 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      121.94,-19.41 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 205.83,18.48 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(0.0<100sec) coincident with the FERMI_GBM event (trignum=264304486).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 01:58:02 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.937d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.764d {+00d 45' 50"} (J2000)
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  6957.77 SOD {01:55:57.77} UT,   73.5 [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:     Mon 18 May 09 02:00:16 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     352420,   Seg_Num: 0
GRB_RA:          119.933d {+07h 59m 44s} (J2000),
                 120.054d {+08h 00m 13s} (current),
                 119.289d {+07h 57m 09s} (1950)
GRB_DEC:          +0.768d {+00d 46' 04"} (J2000),
                  +0.742d {+00d 44' 30"} (current),
                  +0.905d {+00d 54' 20"} (1950)
GRB_DATE:        14969 TJD;   138 DOY;   09/05/18
GRB_TIME:        6884.27 SOD {01:54:44.27} UT
TRIGGER_INDEX:   37
GRB_PHI:         -45.76 [deg]
GRB_THETA:        26.85 [deg]
DELTA_TIME:      57.00 [sec]
TRIGGER_DUR:     0.256 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     14.62 [sigma]
IMAGE_SIGNIF:    9.03 [sigma]
LC_URL:          sw00352420000msb.lc
SUN_POSTN:        54.99d {+03h 39m 59s}  +19.55d {+19d 32' 59"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.52d {+22h 26m 04s}   -6.76d {-06d 45' 45"}
MOON_DIST:       143.14 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.20, 15.51 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      121.94,-19.41 [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 = 205.83,18.48 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:00:56 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.937d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.764d {+00d 45' 50"} (J2000)
POINT_ROLL:      291.081d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  6961.47 SOD {01:56:01.47} UT,   77.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.528
N_STARS:         140
X_OFFSET:        539 [pixels]
Y_OFFSET:        557 [pixels]
X_MAX:           1498 [pixels]
Y_MAX:           1516 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00352420000msufc0077.fits
SUN_POSTN:        54.99d {+03h 39m 59s}  +19.55d {+19d 32' 59"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.52d {+22h 26m 05s}   -6.76d {-06d 45' 36"}
MOON_DIST:       143.14 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.94,-19.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:01:36 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.937d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.764d {+00d 45' 50"} (J2000)
POINT_ROLL:      291.081d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  6961.47 SOD {01:56:01.47} UT,   77.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.528
N_STARS:         140
X_OFFSET:        539 [pixels]
Y_OFFSET:        557 [pixels]
X_MAX:           1498 [pixels]
Y_MAX:           1516 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00352420000msufc0077.fits
SUN_POSTN:        55.00d {+03h 39m 59s}  +19.55d {+19d 32' 60"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.53d {+22h 26m 07s}   -6.76d {-06d 45' 27"}
MOON_DIST:       143.13 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.94,-19.42 [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:     Mon 18 May 09 02:03:00 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     352420,   Seg_Num: 0
GRB_RA:          119.9552d {+07h 59m 49.24s} (J2000),
                 120.0759d {+08h 00m 18.22s} (current),
                 119.3112d {+07h 57m 14.68s} (1950)
GRB_DEC:          +0.7587d {+00d 45' 31.3"} (J2000),
                  +0.7326d {+00d 43' 57.3"} (current),
                  +0.8964d {+00d 53' 46.8"} (1950)
GRB_ERROR:       3.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  6975.00 SOD {01:56:15.00} UT,   90.7 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        55.00d {+03h 39m 59s}  +19.55d {+19d 33' 00"}
SUN_DIST:         66.34 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.54d {+22h 26m 09s}   -6.75d {-06d 45' 09"}
MOON_DIST:       143.14 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.22, 15.52 [deg] galactic lon,lat of the burst
ECL_COORDS:      121.96,-19.42 [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.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:00:56 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.937d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.764d {+00d 45' 50"} (J2000)
POINT_ROLL:      291.081d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  6961.47 SOD {01:56:01.47} UT,   77.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.528
N_STARS:         140
X_OFFSET:        539 [pixels]
Y_OFFSET:        557 [pixels]
X_MAX:           1498 [pixels]
Y_MAX:           1516 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00352420000msufc0077.fits
SUN_POSTN:        54.99d {+03h 39m 59s}  +19.55d {+19d 32' 59"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.52d {+22h 26m 05s}   -6.76d {-06d 45' 36"}
MOON_DIST:       143.14 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.94,-19.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:04:10 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     9085451,   Seg_Num: 6
POINT_RA:          0.000d {+00h 00m 00s} (J2000)
POINT_DEC:        +0.000d {+00d 00' 00"} (J2000)
ROLL:            0.000d
IMG_START_DATE:  52718 TJD;   37887 DOY;   09/135424885/146856872
IMG_START_TIME:  29203.07 SOD {08:06:43.07} UT,   22318.8 [sec] since BAT Trigger Time
FILTER:          0, illegal value
EXPOSURE_ID:     220531268
X_OFFSET:        1534 [pixels]
Y_OFFSET:        55 [pixels]
WIDTH:           1888 [pixels]
HEIGHT:          1527 [pixels]
X_GRB_POS:       191
Y_GRB_POS:       1414
BINNING_INDEX:   12
IM_URL:          sw00352420000msuni0082.fits
SUN_POSTN:        55.00d {+03h 39m 59s}  +19.55d {+19d 33' 01"}
SUN_DIST:         55.70 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      336.55d {+22h 26m 11s}   -6.75d {-06d 44' 53"}
MOON_DIST:        25.92 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:       96.34,-60.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        0.00,  0.00 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        This Notice is generated as a result of an uploaded TOO on an old GRB -- this is not a newly detected burst.  
COMMENTS:        And the IMG_START_DATE/TIME fields are the current epoch -- not the original detection.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        This notice was forced out after watchdog timer expiring -- most likely due to missing packet(s);  
COMMENTS:        as a consequence some of the fields may be incoorect (eg TRIGGER_NUM,RA,DEC).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:04:36 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     9085451,   Seg_Num: 6
POINT_RA:          0.000d {+00h 00m 00s} (J2000)
POINT_DEC:        +0.000d {+00d 00' 00"} (J2000)
ROLL:            0.000d
IMG_START_DATE:  52718 TJD;   37887 DOY;   09/135424885/146856872
IMG_START_TIME:  29203.07 SOD {08:06:43.07} UT,   22318.8 [sec] since BAT Trigger Time
FILTER:          0, illegal value
EXPOSURE_ID:     220531268
X_OFFSET:        1534 [pixels]
Y_OFFSET:        55 [pixels]
WIDTH:           1888 [pixels]
HEIGHT:          1527 [pixels]
X_GRB_POS:       191
Y_GRB_POS:       1414
BINNING_INDEX:   12
IM_URL:          sw00352420000msuni0082.fits
SUN_POSTN:        55.00d {+03h 39m 59s}  +19.55d {+19d 33' 01"}
SUN_DIST:         55.70 [deg]   Sun_angle= 3.7 [hr] (West of Sun)
MOON_POSTN:      336.55d {+22h 26m 12s}   -6.75d {-06d 44' 47"}
MOON_DIST:        25.91 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:       96.34,-60.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        0.00,  0.00 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        This Notice is generated as a result of an uploaded TOO on an old GRB -- this is not a newly detected burst.  
COMMENTS:        And the IMG_START_DATE/TIME fields are the current epoch -- not the original detection.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        All 4 attachments are included.  
COMMENTS:        This notice was forced out after watchdog timer expiring -- most likely due to missing packet(s);  
COMMENTS:        as a consequence some of the fields may be incoorect (eg TRIGGER_NUM,RA,DEC).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:10:16 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
POINT_ROLL:      291.083d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7173.83 SOD {01:59:33.83} UT,   289.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.987
N_STARS:         190
X_OFFSET:        299 [pixels]
Y_OFFSET:        317 [pixels]
X_MAX:           1738 [pixels]
Y_MAX:           1756 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00352420000msufc0289.fits
SUN_POSTN:        55.00d {+03h 40m 00s}  +19.55d {+19d 33' 04"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.59d {+22h 26m 23s}   -6.73d {-06d 43' 32"}
MOON_DIST:       143.07 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:10:54 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
POINT_ROLL:      291.083d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7173.83 SOD {01:59:33.83} UT,   289.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.987
N_STARS:         190
X_OFFSET:        299 [pixels]
Y_OFFSET:        317 [pixels]
X_MAX:           1738 [pixels]
Y_MAX:           1756 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00352420000msufc0289.fits
SUN_POSTN:        55.00d {+03h 40m 00s}  +19.55d {+19d 33' 05"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.60d {+22h 26m 24s}   -6.72d {-06d 43' 23"}
MOON_DIST:       143.07 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [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:     Mon 18 May 09 02:11:39 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
ROLL:            291.083d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7173.83 SOD {01:59:33.83} UT,   289.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     264304778
X_OFFSET:        858 [pixels]
Y_OFFSET:        876 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1018
Y_GRB_POS:       1036
BINNING_INDEX:   1
IM_URL:          sw00352420000msuni0294.fits
SUN_POSTN:        55.00d {+03h 40m 01s}  +19.55d {+19d 33' 05"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.61d {+22h 26m 25s}   -6.72d {-06d 43' 13"}
MOON_DIST:       143.06 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [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:     Mon 18 May 09 02:12:06 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
ROLL:            291.083d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7173.83 SOD {01:59:33.83} UT,   289.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     264304778
X_OFFSET:        858 [pixels]
Y_OFFSET:        876 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1018
Y_GRB_POS:       1036
BINNING_INDEX:   1
IM_URL:          sw00352420000msuni0294.fits
SUN_POSTN:        55.00d {+03h 40m 01s}  +19.55d {+19d 33' 05"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.61d {+22h 26m 26s}   -6.72d {-06d 43' 07"}
MOON_DIST:       143.06 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [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:     Mon 18 May 09 02:12:36 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     352420,   Seg_Num: 0
GRB_RA:          119.9542d {+07h 59m 49.00s} (J2000),
                 120.0749d {+08h 00m 17.98s} (current),
                 119.3102d {+07h 57m 14.44s} (1950)
GRB_DEC:          +0.7590d {+00d 45' 32.4"} (J2000),
                  +0.7329d {+00d 43' 58.3"} (current),
                  +0.8967d {+00d 53' 47.9"} (1950)
GRB_ERROR:       2.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  6975.00 SOD {01:56:15.00} UT,   90.7 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        55.00d {+03h 40m 01s}  +19.55d {+19d 33' 06"}
SUN_DIST:         66.33 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.61d {+22h 26m 27s}   -6.72d {-06d 43' 00"}
MOON_DIST:       143.07 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.22, 15.52 [deg] galactic lon,lat of the burst
ECL_COORDS:      121.96,-19.42 [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

GCN Circular #9386
P. A. Evans (U Leicester), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), A. Rowlinson (U Leicester), M. H. Siegel (PSU), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the Swift Team:
At 01:54:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090518 (trigger=352420). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 119.933, +0.768 which is
```
   RA(J2000) = 07h 59m 44s
   Dec(J2000) = +00d 46' 04"
```
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 5 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 01:55:57.8 UT, 73.5 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 119.95519, 0.75892 which is equivalent to:
```
   RA(J2000)  = 07h 59m 49.25s
   Dec(J2000) = +00d 45' 32.1"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 86 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (4.65e+20 cm^-2, Kalberla et al. 2005), with an excess column of 4.9 (+3.56/-2.94) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 77 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 0.04.
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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:17:20 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     352417,   Seg_Num: 0
POINT_RA:        129.573d {+08h 38m 18s} (J2000)
POINT_DEC:       -24.411d {-24d 24' 38"} (J2000)
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  6431.00 SOD {01:47:11.00} UT,   85946.7 [sec] since BAT Trigger Time
COUNTS:          10000    Min_needed= 0
STD_DEV:         0.00   Max_StdDev_for_Good=0.00 [arcsec]
PH2_ITER:        0    Max_iter_allowed= 287
ERROR_CODE:      16385
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        UNRECOGNIZED ERROR CODE.  
COMMENTS:        SPER date was used (by the UL processing) to determine this trigger is a non-burst trigger.  
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.php for details.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:18:16 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
POINT_ROLL:      291.082d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7752.31 SOD {02:09:12.31} UT,   868.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.383
N_STARS:         190
X_OFFSET:        299 [pixels]
Y_OFFSET:        317 [pixels]
X_MAX:           1738 [pixels]
Y_MAX:           1756 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00352420000msufc0868.fits
SUN_POSTN:        55.01d {+03h 40m 02s}  +19.55d {+19d 33' 09"}
SUN_DIST:         66.31 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.66d {+22h 26m 38s}   -6.70d {-06d 41' 44"}
MOON_DIST:       143.02 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:18:54 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
POINT_ROLL:      291.082d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7752.31 SOD {02:09:12.31} UT,   868.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.383
N_STARS:         190
X_OFFSET:        299 [pixels]
Y_OFFSET:        317 [pixels]
X_MAX:           1738 [pixels]
Y_MAX:           1756 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00352420000msufc0868.fits
SUN_POSTN:        55.01d {+03h 40m 02s}  +19.55d {+19d 33' 09"}
SUN_DIST:         66.31 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.66d {+22h 26m 39s}   -6.69d {-06d 41' 36"}
MOON_DIST:       143.01 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [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:     Mon 18 May 09 02:19:52 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
ROLL:            291.082d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7752.31 SOD {02:09:12.31} UT,   868.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     264305357
X_OFFSET:        858 [pixels]
Y_OFFSET:        876 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1018
Y_GRB_POS:       1036
BINNING_INDEX:   1
IM_URL:          sw00352420000msuni0873.fits
SUN_POSTN:        55.01d {+03h 40m 02s}  +19.55d {+19d 33' 10"}
SUN_DIST:         66.31 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.67d {+22h 26m 41s}   -6.69d {-06d 41' 23"}
MOON_DIST:       143.00 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [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:     Mon 18 May 09 02:20:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
ROLL:            291.082d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7752.31 SOD {02:09:12.31} UT,   868.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     264305357
X_OFFSET:        858 [pixels]
Y_OFFSET:        876 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1018
Y_GRB_POS:       1036
BINNING_INDEX:   1
IM_URL:          sw00352420000msuni0873.fits
SUN_POSTN:        55.01d {+03h 40m 02s}  +19.55d {+19d 33' 10"}
SUN_DIST:         66.31 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.67d {+22h 26m 42s}   -6.69d {-06d 41' 15"}
MOON_DIST:       143.00 [deg]
MOON_ILLUM:      42 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [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:     Mon 18 May 09 02:10:16 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
POINT_ROLL:      291.083d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7173.83 SOD {01:59:33.83} UT,   289.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.987
N_STARS:         190
X_OFFSET:        299 [pixels]
Y_OFFSET:        317 [pixels]
X_MAX:           1738 [pixels]
Y_MAX:           1756 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00352420000msufc0289.fits
SUN_POSTN:        55.00d {+03h 40m 00s}  +19.55d {+19d 33' 04"}
SUN_DIST:         66.32 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.59d {+22h 26m 23s}   -6.73d {-06d 43' 32"}
MOON_DIST:       143.07 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 18 May 09 02:18:16 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     352420,   Seg_Num: 0
POINT_RA:        119.939d {+07h 59m 45s} (J2000)
POINT_DEC:        +0.761d {+00d 45' 40"} (J2000)
POINT_ROLL:      291.082d
IMG_START_DATE:  14969 TJD;   138 DOY;   09/05/18
IMG_START_TIME:  7752.31 SOD {02:09:12.31} UT,   868.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.383
N_STARS:         190
X_OFFSET:        299 [pixels]
Y_OFFSET:        317 [pixels]
X_MAX:           1738 [pixels]
Y_MAX:           1756 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00352420000msufc0868.fits
SUN_POSTN:        55.01d {+03h 40m 02s}  +19.55d {+19d 33' 09"}
SUN_DIST:         66.31 [deg]   Sun_angle= -4.3 [hr] (East of Sun)
MOON_POSTN:      336.66d {+22h 26m 38s}   -6.70d {-06d 41' 44"}
MOON_DIST:       143.02 [deg]
MOON_ILLUM:      43 [%]
GAL_COORDS:      220.21, 15.51 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      121.95,-19.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN Circular #9387
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 3965 s of XRT Photon Counting mode data and 8 UVOT images for GRB 090518, 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 = 119.95404, +0.75921 which is equivalent to:
```
RA (J2000): 07h 59m 48.97s
Dec (J2000): +00d 45' 33.2"
```
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, arXiv:0812.3662).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #9388
P. A. Evans (U Leicester) reports on behalf of the Swift-XRT team:
We have analysed 6.4 ks of XRT data for GRB 090518 (Evans et al. GCN Circ. 9386), from 88 s to 13.0 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN. Circ 9387).
The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=1.5 (+0.4, -0.3). At T+332 s the decay flattens to an alpha of 0.29 (+0.16, -0.38) before breaking again at T+2743 s to a final decay with index alpha=1.1 (+/-0.3).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.1 (+/-0.4). The best-fitting absorption column is 6.2 (+2.3, -1.9) x 10^21 cm^-2, in excess of the Galactic value of 4.6 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.9 x 10^-11 (9.9 x 10^-11) erg cm^-2 count^-1.
If the light curve continues to decay with a power-law decay index of 1.1, the count rate at T+24 hours will be 0.0031 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.5 x 10^-13 (3.1 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00352420.
This circular is an official product of the Swift-XRT team.
GCN Circular #9389
T. Sako, A. Fukui, K. Nishimoto (STE Lab, Nagoya Univ.) on behalf of the MOA Collabration report:
We searched for an optical afterglow of GRB090518 (GCN 9386, Evans et al.; GCN 9387, Evans et al.) starting from 7:02:10 UT (5 hours after the burst) with the MOA-II 1.8m telescope at Mt.John observatory in New Zealand. In a single image of a 300sec exposure with a wideband Red filter (center wavelength ~ 750nm and FWHM ~ 250nm), we did not find any object within the error circle of the Swift XRT source position (GCN 9387). A 5 sigma upper limit is set in the I magnitude at 18.9 mag. This photometry was done by using the DoPhoto and calibrated against the USNO-B1.0 catalog stars, and not corrected for the Galactic extinction.
GCN Circular #9393
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-119 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 090518 (trigger #352420) (Evans, et al., GCN Circ. 9386). The BAT ground-calculated position is RA, Dec = 119.957, 0.778 deg which is
```
   RA(J2000)  =  07h 59m 49.6s 
   Dec(J2000) = +00d 46' 41.4" 
```
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 75%.
The mask-weighted light curve shows a FRED-like peak starting at T-0.5 sec, peaking at T+0 sec, and ending at T+3 sec. T90 (15-350 keV) is 6.9 +- 1.7 sec (estimated error including systematics).
The time-averaged spectrum from T-2.4 to T+6.9 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.54 +- 0.14. The fluence in the 15-150 keV band is 4.7 +- 0.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T-0.08 sec in the 15-150 keV band is 2.4 +- 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/352420/BA/
GCN Circular #9394
S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration:
We have imaged the field of GRB090518 (Evans et al., GCN 9386) with the automated Palomar 60-inch telescope beginning at 3:45 UT on 2009 May 18 (~ 1.83 hr after the burst). Observations were taken in the r', i', and z' filters at high airmass. We find no sources inside the enhanced XRT error circle (Evans et al., GCN 9387), to the following limiting magnitudes:
```
Filter     Magnitude
--------------------------------
r'         > 20.5
i'         > 20.0
z'         > 19.0
```
No correction has been applied for Galactic extinction along the line of sight.
GCN Circular #9395
A. Rossi (Tautenburg), P. Afonso and J. Greiner( both MPE Garching) report on behalf of the GROND team:
GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile), observed the field of GRB 090518 (P. Evans et al. 2009, GCN #9386) simultaneously in the g'r'i'z'JHK bands. Observations started on May 18, at 23:01 UTC, 21.1 h after the burst. In stacked images of 49 min total integration time in griz and 40 min in JHK, we do not detect any new object inside the enhanced XRT error circle (P. Evans et al., GCN #9387), down to the following limiting magnitudes (all in the AB system):
```
g' > 24.5
r' > 24.9
i' > 24.2
z' > 23.8
J  > 22.4
H  > 22.1
K  > 21.2
```
The upper limits have been obtained using GROND zero points and 2MASS field stars as reference. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04 mag.
GCN Circular #9397
F.E. Marshall (NASA/GSFC) and P. Evans (U. Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 090518 starting 77 s after the BAT trigger (Evans et al., GCN Circ. 9386). No optical afterglow is detected in the initial UVOT exposures at the position of the X-ray afterglow (Evans et al., GCN Circ. 9387). Three-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter          T_start(s)   T_stop(s)      Exp(s)        Mag 

white (FC)          77          227          147         >20.7
white               77         1367          373         >21.3
v                  620         1417           97         >19.3
b                  545         1341           78         >19.7
u                  290         1316          304         >20.0
uvw1               669         1466           97         >19.7
uvm2               644         1442           97         >21.2
uvw2               596         1392           97         >20.0
```
The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #9419
W. Paciesas (UAH) reports on behalf of the Fermi GBM Team:
"At 01:54:44.52 UT on 18 May 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090518 (trigger 264304486 / 090518080). which was also detected by the SWIFT-BAT (Evans et al. 2009, GCN 9386) The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 53 degrees.
The GBM light curve consists of a single asymmetric peak with a duration (T90) of about 9 s (8-1000 keV). The time-averaged spectrum from T0-2.048 s to T0+7.04 s is adequately fit by a simple power law function with index -1.59 +/- 0.06 (chi squared 688 for 688 d.o.f.).
The event fluence (8-1000 keV) in this time interval is (1.60 +/- 0.05)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.64 s in the 8-1000 keV band is 4.7 +/- 0.1 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #9423
C. C. Thoene (INAF/OAB), E. Kankare (NOT), J. P. U. Fynbo, D. Malesani (DARK/NBI), A. J. Levan (Univ. Warwick), P. Jakobsson (Univ. Iceland), J. Hjorth (DARK/NBI) report:
We observed the field of GRB 090518 (GCN 9386, Evans et al.) with ALFOSC/NOT on La Palma starting May 18, 20:54 UT (21 h after the burst). Observations were obtained in R (3x300s), I (3x300s) and z (6x200s) filters at high airmass.
We do not detect any new source at the XRT position (GCN 9387, Evans et al.) in the summed image of each filter. The following upper limits were obtained (based on USNO B1.0 reference stars and a NOT z-band archival zeropoint):
```
R > 23.7 mag
I > 21.8 mag
z(AB) > 22.5 mag
```

GCN Circular #10002
J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander report:
Skynet observed the Swift/BAT localization of GRB 090518 (Evans et al., GCN 9386) with four of the 16" PROMPT telescopes at CTIO beginning 3.3 minutes after the trigger in UVRI.
We do not detect the afterglow (Evans et al., GCN 9386) within the enhanced Swift/XRT localization (Evans et al., GCN 9387). Stacking only images that increase the limiting magnitude yields:

mean                                                  1-sig.  1-sig.
time                             3-sig.               sys.    stat.
since                            lim.    cal.         cal.    cal.
trig.  tel.      exp.      fil.  mag.    stars        unc.    unc.
(m)              (# x s)                              (mag)   (mag)

5.2    PROMPT-4  4 x 40    I    18.2     229 USNO B1  0.372   0.001
                  + 1 x 10
5.8    PROMPT-5  2 x 40    V    18.3     72 NOMAD     0.146   0.001
6.4    PROMPT-2  1 x 80    R    19.3     217 USNO B1  0.305   0.001
                  + 2 x 40

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Jochen Greiner, last update: 09-Oct-2009 [Disclaimer]