Gamma-ray Burst 180504A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

 
TITLE:           GCN/SWIFT NOTICE 
NOTICE_DATE:     Fri 04 May 18 19:48:25 UT 
NOTICE_TYPE:     Swift-XRT Position 
TRIGGER_NUM:     830822,   Seg_Num: 0 
GRB_RA:          331.1428d {+22h 04m 34.27s} (J2000), 
                 331.3906d {+22h 05m 33.73s} (current), 
                 330.4664d {+22h 01m 51.94s} (1950) 
GRB_DEC:         -14.6599d {-14d 39' 35.6"} (J2000), 
                 -14.5704d {-14d 34' 13.3"} (current), 
                 -14.9029d {-14d 54' 10.5"} (1950) 
GRB_ERROR:       5.6 [arcsec radius, statistical plus systematic, 90% containment] 
GRB_INTEN:       9.57e-10 [erg/cm2/sec] 
GRB_SIGNIF:      6.70 [sigma] 
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04 
IMG_START_TIME:  71280.99 SOD {19:48:00.99} UT 
TAM[0-3]:        327.65 237.18 261.59 243.73 
AMPLIFIER:       2 
WAVEFORM:        134 
SUN_POSTN:        41.84d {+02h 47m 21s}  +16.13d {+16d 07' 38"} 
SUN_DIST:         76.04 [deg]   Sun_angle= 4.7 [hr] (West of Sun) 
MOON_POSTN:      279.36d {+18h 37m 26s}  -20.62d {-20d 37' 06"} 
MOON_DIST:        49.77 [deg] 
MOON_ILLUM:      79 [%] 
GAL_COORDS:       42.11,-49.30 [deg] galactic lon,lat of the burst 
ECL_COORDS:      328.02, -2.66 [deg] ecliptic lon,lat of the burst 
COMMENTS:        SWIFT-XRT Coordinates.   
COMMENTS:            
COMMENTS:        WARNING: No BAT_Position TDRSS message was received for this trigger_number!   
COMMENTS:

GCN NOTICE

 
TITLE:           GCN/SWIFT NOTICE 
NOTICE_DATE:     Fri 04 May 18 19:48:37 UT 
NOTICE_TYPE:     Swift-XRT Image 
TRIGGER_NUM:     830822,   Seg_Num: 0 
GRB_RA:          331.1428d {+22h 04m 34.2s} (J2000), 
                 331.3906d {+22h 05m 33.7s} (current), 
                 330.4664d {+22h 01m 51.9s} (1950) 
GRB_DEC:         -14.6599d {-14d 39' 35.6"} (J2000), 
                 -14.5704d {-14d 34' 13.3"} (current), 
                 -14.9029d {-14d 54' 10.5"} (1950) 
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic] 
GRB_INTEN:       45 [cnts] 
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04 
IMG_START_TIME:  71280.99 SOD {19:48:00.99} UT 
CENTROID_X:      324.63,  raw= 325  [pixels] 
CENTROID_Y:      268.74,  raw= 269  [pixels] 
ROLL:            68.98 [deg] 
GAIN:            1 
MODE:            3, Long Image mode 
WAVEFORM:        134 
EXPO_TIME:       2.50 [sec] 
GRB_POS_XRT_Y:   -69.89 
GRB_POS_XRT_Z:   42.98 
IMAGE_URL:       sw00830822000msxps_rw.img 
SUN_POSTN:        41.84d {+02h 47m 21s}  +16.13d {+16d 07' 38"} 
SUN_DIST:         76.04 [deg]   Sun_angle= 4.7 [hr] (West of Sun) 
MOON_POSTN:      279.36d {+18h 37m 27s}  -20.62d {-20d 37' 06"} 
MOON_DIST:        49.77 [deg] 
MOON_ILLUM:      79 [%] 
GAL_COORDS:       42.11,-49.30 [deg] galactic lon,lat of the burst 
ECL_COORDS:      328.02, -2.66 [deg] ecliptic lon,lat of the burst 
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 19:48:41 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     830822,   Seg_Num: 0
GRB_RA:          331.1428d {+22h 04m 34.2s} (J2000),
                 331.3906d {+22h 05m 33.7s} (current),
                 330.4664d {+22h 01m 51.9s} (1950)
GRB_DEC:         -14.6599d {-14d 39' 35.6"} (J2000),
                 -14.5704d {-14d 34' 13.3"} (current),
                 -14.9029d {-14d 54' 10.5"} (1950)
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       45 [cnts]
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  71280.99 SOD {19:48:00.99} UT
CENTROID_X:      324.63,  raw= 325  [pixels]
CENTROID_Y:      268.74,  raw= 269  [pixels]
ROLL:            68.98 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -69.89
GRB_POS_XRT_Z:   42.98
IMAGE_URL:       sw00830822000msxps_rw.img
SUN_POSTN:        41.84d {+02h 47m 21s}  +16.13d {+16d 07' 38"}
SUN_DIST:         76.04 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.36d {+18h 37m 27s}  -20.62d {-20d 37' 06"}
MOON_DIST:        49.77 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.11,-49.30 [deg] galactic lon,lat of the burst
ECL_COORDS:      328.02, -2.66 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 19:49:45 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     830822,   Seg_Num: 0
GRB_RA:          331.134d {+22h 04m 32s} (J2000),
                 331.381d {+22h 05m 32s} (current),
                 330.457d {+22h 01m 50s} (1950)
GRB_DEC:         -14.655d {-14d 39' 17"} (J2000),
                 -14.565d {-14d 33' 54"} (current),
                 -14.898d {-14d 53' 51"} (1950)
GRB_DATE:        18242 TJD;   124 DOY;   18/05/04
GRB_TIME:        71173.28 SOD {19:46:13.28} UT
TRIGGER_INDEX:   334
GRB_PHI:          74.68 [deg]
GRB_THETA:        23.65 [deg]
DELTA_TIME:      -57.00 [sec]
TRIGGER_DUR:      [sec],  copy from BAT_POS unavailable
SOLN_STATUS:     0x0
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    0.00 [sigma]
LC_URL:          sw00830822000msb.lc
SUN_POSTN:        41.84d {+02h 47m 21s}  +16.13d {+16d 07' 39"}
SUN_DIST:         76.04 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.37d {+18h 37m 29s}  -20.62d {-20d 37' 06"}
MOON_DIST:        49.75 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.11,-49.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      328.01, -2.66 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        WARNING: No BAT_Position TDRSS message was received for this trigger_number!  
COMMENTS:           
COMMENTS:        This does not match any source in the ground catalog.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 19:51:21 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.147d {+22h 04m 35s} (J2000)
POINT_DEC:       -14.638d {-14d 38' 15"} (J2000)
POINT_ROLL:      68.982d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  71290.97 SOD {19:48:10.97} UT
FILTER:          10, White
BKG_MEAN:        4.182
N_STARS:         26
X_OFFSET:        392 [pixels]
Y_OFFSET:        712 [pixels]
X_MAX:           1351 [pixels]
Y_MAX:           1671 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00830822000msufc547156090.fits
SUN_POSTN:        41.84d {+02h 47m 21s}  +16.13d {+16d 07' 40"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.39d {+18h 37m 32s}  -20.62d {-20d 37' 06"}
MOON_DIST:        49.75 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 19:51:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.147d {+22h 04m 35s} (J2000)
POINT_DEC:       -14.638d {-14d 38' 15"} (J2000)
POINT_ROLL:      68.982d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  71290.97 SOD {19:48:10.97} UT
FILTER:          10, White
BKG_MEAN:        4.182
N_STARS:         26
X_OFFSET:        392 [pixels]
Y_OFFSET:        712 [pixels]
X_MAX:           1351 [pixels]
Y_MAX:           1671 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00830822000msufc547156090.fits
SUN_POSTN:        41.84d {+02h 47m 21s}  +16.13d {+16d 07' 40"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.39d {+18h 37m 33s}  -20.62d {-20d 37' 06"}
MOON_DIST:        49.75 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [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 04 May 18 19:53:16 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.147d {+22h 04m 35s} (J2000)
POINT_DEC:       -14.638d {-14d 38' 15"} (J2000)
ROLL:            68.982d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  71290.97 SOD {19:48:10.97} UT
FILTER:          10, White
EXPOSURE_ID:     547156111
X_OFFSET:        777 [pixels]
Y_OFFSET:        1051 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       937
Y_GRB_POS:       1211
BINNING_INDEX:   1
IM_URL:          sw00830822000msuni547156111.fits
SUN_POSTN:        41.84d {+02h 47m 21s}  +16.13d {+16d 07' 41"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.40d {+18h 37m 36s}  -20.62d {-20d 37' 07"}
MOON_DIST:        49.74 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 19:53:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.147d {+22h 04m 35s} (J2000)
POINT_DEC:       -14.638d {-14d 38' 15"} (J2000)
ROLL:            68.982d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  71290.97 SOD {19:48:10.97} UT
FILTER:          10, White
EXPOSURE_ID:     547156111
X_OFFSET:        777 [pixels]
Y_OFFSET:        1051 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       937
Y_GRB_POS:       1211
BINNING_INDEX:   1
IM_URL:          sw00830822000msuni547156111.fits
SUN_POSTN:        41.84d {+02h 47m 22s}  +16.13d {+16d 07' 41"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.40d {+18h 37m 37s}  -20.62d {-20d 37' 07"}
MOON_DIST:        49.74 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 19:59:25 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.149d {+22h 04m 36s} (J2000)
POINT_DEC:       -14.636d {-14d 38' 09"} (J2000)
POINT_ROLL:      68.981d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  71449.15 SOD {19:50:49.15} UT
FILTER:          7, U
BKG_MEAN:        1.242
N_STARS:         21
X_OFFSET:        457 [pixels]
Y_OFFSET:        731 [pixels]
X_MAX:           1416 [pixels]
Y_MAX:           1690 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00830822000msufc547156249.fits
SUN_POSTN:        41.84d {+02h 47m 22s}  +16.13d {+16d 07' 46"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.46d {+18h 37m 50s}  -20.62d {-20d 37' 09"}
MOON_DIST:        49.69 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 19:59:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.149d {+22h 04m 36s} (J2000)
POINT_DEC:       -14.636d {-14d 38' 09"} (J2000)
POINT_ROLL:      68.981d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  71449.15 SOD {19:50:49.15} UT
FILTER:          7, U
BKG_MEAN:        1.242
N_STARS:         21
X_OFFSET:        457 [pixels]
Y_OFFSET:        731 [pixels]
X_MAX:           1416 [pixels]
Y_MAX:           1690 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00830822000msufc547156249.fits
SUN_POSTN:        41.84d {+02h 47m 23s}  +16.13d {+16d 07' 46"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.46d {+18h 37m 50s}  -20.62d {-20d 37' 09"}
MOON_DIST:        49.69 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [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 04 May 18 20:00:52 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.149d {+22h 04m 36s} (J2000)
POINT_DEC:       -14.636d {-14d 38' 09"} (J2000)
ROLL:            68.981d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  71449.15 SOD {19:50:49.15} UT
FILTER:          7, U
EXPOSURE_ID:     547156270
X_OFFSET:        777 [pixels]
Y_OFFSET:        1051 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       937
Y_GRB_POS:       1211
BINNING_INDEX:   1
IM_URL:          sw00830822000msuni547156270.fits
SUN_POSTN:        41.84d {+02h 47m 23s}  +16.13d {+16d 07' 47"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.47d {+18h 37m 53s}  -20.62d {-20d 37' 09"}
MOON_DIST:        49.68 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 20:01:06 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.149d {+22h 04m 36s} (J2000)
POINT_DEC:       -14.636d {-14d 38' 09"} (J2000)
ROLL:            68.981d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  71449.15 SOD {19:50:49.15} UT
FILTER:          7, U
EXPOSURE_ID:     547156270
X_OFFSET:        777 [pixels]
Y_OFFSET:        1051 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       937
Y_GRB_POS:       1211
BINNING_INDEX:   1
IM_URL:          sw00830822000msuni547156270.fits
SUN_POSTN:        41.84d {+02h 47m 23s}  +16.13d {+16d 07' 47"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.47d {+18h 37m 53s}  -20.62d {-20d 37' 09"}
MOON_DIST:        49.67 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #22682
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J.D. Gropp (PSU), J. A. Kennea (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), A. Tohuvavohu (PSU) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Neil Gehrels Swift Observatory Team:
At 19:46:13 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180504A (trigger=830822). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 331.134, -14.655 which is
```
   RA(J2000) = 22h 04m 32s
   Dec(J2000) = -14d 39' 17"
```
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 50 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger.
Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 331.14235, -14.65988 which is equivalent to:
```
   RA(J2000)  = 22h 04m 34.16s
   Dec(J2000) = -14d 39' 35.6"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 3.50 x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 9.57e-10 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 117 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04.
Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 20:06:05 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.149d {+22h 04m 36s} (J2000)
POINT_DEC:       -14.636d {-14d 38' 09"} (J2000)
POINT_ROLL:      68.981d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  72053.35 SOD {20:00:53.35} UT
FILTER:          10, White
BKG_MEAN:        4.554
N_STARS:         50
X_OFFSET:        217 [pixels]
Y_OFFSET:        491 [pixels]
X_MAX:           1656 [pixels]
Y_MAX:           1930 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00830822000msufc547156853.fits
SUN_POSTN:        41.85d {+02h 47m 24s}  +16.13d {+16d 07' 51"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.52d {+18h 38m 04s}  -20.62d {-20d 37' 10"}
MOON_DIST:        49.63 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 04 May 18 20:06:18 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.149d {+22h 04m 36s} (J2000)
POINT_DEC:       -14.636d {-14d 38' 09"} (J2000)
POINT_ROLL:      68.981d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  72053.35 SOD {20:00:53.35} UT
FILTER:          10, White
BKG_MEAN:        4.554
N_STARS:         50
X_OFFSET:        217 [pixels]
Y_OFFSET:        491 [pixels]
X_MAX:           1656 [pixels]
Y_MAX:           1930 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00830822000msufc547156853.fits
SUN_POSTN:        41.85d {+02h 47m 24s}  +16.13d {+16d 07' 51"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.52d {+18h 38m 04s}  -20.62d {-20d 37' 10"}
MOON_DIST:        49.63 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [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 04 May 18 20:07:29 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.149d {+22h 04m 36s} (J2000)
POINT_DEC:       -14.636d {-14d 38' 09"} (J2000)
ROLL:            68.981d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  72053.35 SOD {20:00:53.35} UT
FILTER:          10, White
EXPOSURE_ID:     547156874
X_OFFSET:        776 [pixels]
Y_OFFSET:        1050 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       936
Y_GRB_POS:       1210
BINNING_INDEX:   1
IM_URL:          sw00830822000msuni547156874.fits
SUN_POSTN:        41.85d {+02h 47m 24s}  +16.13d {+16d 07' 52"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.53d {+18h 38m 07s}  -20.62d {-20d 37' 11"}
MOON_DIST:        49.62 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [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 04 May 18 20:07:35 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     830822,   Seg_Num: 0
POINT_RA:        331.149d {+22h 04m 36s} (J2000)
POINT_DEC:       -14.636d {-14d 38' 09"} (J2000)
ROLL:            68.981d
IMG_START_DATE:  18242 TJD;   124 DOY;   18/05/04
IMG_START_TIME:  72053.35 SOD {20:00:53.35} UT
FILTER:          10, White
EXPOSURE_ID:     547156874
X_OFFSET:        776 [pixels]
Y_OFFSET:        1050 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       936
Y_GRB_POS:       1210
BINNING_INDEX:   1
IM_URL:          sw00830822000msuni547156874.fits
SUN_POSTN:        41.85d {+02h 47m 24s}  +16.13d {+16d 07' 52"}
SUN_DIST:         76.03 [deg]   Sun_angle= 4.7 [hr] (West of Sun)
MOON_POSTN:      279.53d {+18h 38m 07s}  -20.62d {-20d 37' 11"}
MOON_DIST:        49.62 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:       42.15,-49.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      328.03, -2.64 [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 #22683
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 180504A, we find an enhanced XRT position of the afterglow: RA, Dec: 331.1442, -14.6583 which is equivalent to:
```
   RA (J2000)  = 22 04 34.61
   Dec (J2000) = -14 39 30.0
```
with an uncertainty of 2.0 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/830822.
Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular #22684
D. Malesani (DAWN/NBI and DARK/NBI) and Illa R. Losada (NOT, Nordita, Stockholm Univ.) report on behalf of a larger collaboration:
We observed the field of GRB 180504A (Lien et al., GCN 22682) with the Nordic Optical Telescope equipped with the AlFOSC camera. The field has a bad visibility from La Palma, and observations were carried out at large airmass (~2) and straddling twilight. The average seeing was 1.5".
Coincident with the UVOT-enhanced position reported by Evans (GCN 22683), we note the presence of a faint source, at a position (J2000; 0.5" error):
```
RA = 22:04:34.61
Dec = -14:39:30.0
```
We note that the automatically reported un-enhanced XRT position (available from http://www.swift.ac.uk/xrt_positions/) is at the time of writing significantly different from the one quoted in the GCN, and would not include our afterglow candidate.
Photometry of the candidate against nearby stars from the Pan-STARRS survey yields r = 22.5 +/- 0.3 (AB) at a mean time 2018 May 5.222 UT (9.57 hr after the trigger)
Further observations are planned.
GCN Circular #22685
V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), A. Melandri (INAF-OAB) and A.Y. Lien report on behalf of the Swift-XRT team:
We have analysed 12 ks of XRT data for GRB 180504A (Lien et al. GCN Circ. 22682), from 98 s to 30.5 ks after the BAT trigger. The data comprise 163 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 = 331.1442, -14.6583 which is equivalent to:
```
RA (J2000): 22 04 34.61
Dec(J2000): -14 39 30.0
```
with an uncertainty of 2.0 arcsec (radius, 90% confidence).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.7 (+nan, -nan).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.80 (+/-0.11). The best-fitting absorption column is 6.9 (+3.2, -2.8) x 10^20 cm^-2, in excess of the Galactic value of 3.5 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.86 (+0.25, -0.23) and a best-fitting absorption column of 1.5 (+0.8, -0.7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (4.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.5 (+0.8, -0.7) x 10^21 cm^-2
Galactic foreground: 3.5 x 10^20 cm^-2
Excess significance: 2.7 sigma
Photon index:	     1.86 (+0.25, -0.23)
```
If the light curve continues to decay with a power-law decay index of 0.7, the count rate at T+24 hours will be 7.4 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.8 x 10^-13 (3.4 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/00830822.
This circular is an official product of the Swift-XRT team.
GCN Circular #22687
P. Clark (QUB), O. McBrien (QUB), D. Malesani (DAWN, DARK), P. D'Avanzo (INAF-OAB), E. Kankare (QUB), M. T. Botticella (INAF Capodimonte), K. Maguire (QUB), M. Dennefeld (IAP, Paris), C. Inserra (Southampton), S. J. Smartt (QUB), O. Yaron (Weizmann), D. R. Young (QUB), I. Manulis (Weizmann) report:
We observed the field of GRB 180504A (Lien et al., GCN Circ. 22682) under the extended Public ESO Spectroscopic Survey for Transient Objects (ePESSTO; see Smartt et al. 2015, A&A, 579, 40 http://www.pessto.org ). The observations were performed on the ESO New Technology Telescope at La Silla with the SofI instrument in imaging mode starting from 2018-05-05 at 08:37:49 UT (i.e. about 12.9 hours from the burst) and consisted of 15 images obtained with the J filter, each one lasting 90s.
The afterglow candidate reported by Malesani et al. (GCN Circ. 22684) is clearly detected. From preliminary photometry, we estimate a magnitude of J ~ 21.3 (Vega, calibrated against the 2MASS catalogue).
GCN Circular #22690
M. Stamatikos (OSU), S. D. Barthelmy (GSFC),=A0 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), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180504A (trigger #830822) (Lien, et al., GCN Circ. 22682).=A0 The BAT ground-calculated position is RA, Dec =3D 331.144, -14.665 deg which is
```
 =A0=A0 RA(J2000)=A0 =3D=A0 22h 04m 34.7s
 =A0=A0 Dec(J2000) =3D -14d 39' 53.6"
```
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 61%.
The mask-weighted light curve shows a triangular shaped profile,=20 beginning at ~T-60 sec, peaking at ~T+20 sec, and decaying by T+80 sec. T90 (15-350 keV) is 88.3 +- 44.4 sec (estimated error including systematics).
The time-averaged spectrum from T-25.03 to T+113.85 sec is best fit by a simple power-law model.=A0 The power law index of the time-averaged spectrum is 1.50 +- 0.13.=A0 The fluence in the 15-150 keV band is 2.2 +- 0.2 x=20 10^-6erg/cm2. The 1-sec peak photon flux measured from T+16.80 sec in the 15-150 keV band is 0.8 +- 0.2 ph/cm2/sec.=A0 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/830822/BA/
GCN Circular #22691
J. D. Gropp (PSU), S. J. LaPorte (PSU), and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180504A 118 s after the BAT trigger (Lien et al., GCN Circ. 22682). No optical afterglow consistent with the enhanced XRT position (Evans GCN Circ. 22683) 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

b                     5159           6793           116      >19.04
uvm2              5978            7606          136      >18.81
u_FC                302            6588          688      >19.53
u                       705            1869          381      >19.47
v                        631              651         136      >18.20
uvw1               6183            6383         136       >18.58
uvw2               5569             7204         136      >18.87
white_FC          143             6998          557     >20.67
white                 582             1746          393    >20.46
```
The magnitudes in the table 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).

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Jochen Greiner, last update: 07-May-2018 [Disclaimer]