Gamma-ray Burst 140518A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:20:25 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     599287,   Seg_Num: 0
  GRB_RA:          227.2519d {+15h 09m 00.45s} (J2000),
                   227.3824d {+15h 09m 31.77s} (current),
                   226.7981d {+15h 07m 11.54s} (1950)
  GRB_DEC:         +42.4174d {+42d 25' 02.6"} (J2000),
                   +42.3631d {+42d 21' 47.3"} (current),
                   +42.6072d {+42d 36' 25.8"} (1950)
  GRB_ERROR:       4.9 [arcsec radius, statistical plus systematic, 90% containment]
  GRB_INTEN:       3.67e-09 [erg/cm2/sec]
  GRB_SIGNIF:      10.29 [sigma]
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33535.02 SOD {09:18:55.02} UT,   46080.2 [sec] since BAT Trigger Time
  TAM[0-3]:        327.69 237.22 261.67 243.32
  AMPLIFIER:       2
  WAVEFORM:        134
  SUN_POSTN:        55.09d {+03h 40m 22s}  +19.57d {+19d 34' 13"}
  SUN_DIST:        117.66 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.82d {+19h 03m 17s}  -17.55d {-17d 33' 14"}
  MOON_DIST:        80.47 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.65, 58.18 [deg] galactic lon,lat of the burst
  ECL_COORDS:      204.57, 56.57 [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:           
  COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
  COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
  COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:20:31 UT
  NOTICE_TYPE:     Swift-XRT Image
  TRIGGER_NUM:     599287,   Seg_Num: 0
  GRB_RA:          227.2519d {+15h 09m 00.4s} (J2000),
                   227.3824d {+15h 09m 31.7s} (current),
                   226.7981d {+15h 07m 11.5s} (1950)
  GRB_DEC:         +42.4174d {+42d 25' 02.6"} (J2000),
                   +42.3631d {+42d 21' 47.3"} (current),
                   +42.6072d {+42d 36' 25.8"} (1950)
  GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       106 [cnts]
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33535.02 SOD {09:18:55.02} UT,   46080.2 [sec] since BAT Trigger Time
  CENTROID_X:      277.28,  raw= 277  [pixels]
  CENTROID_Y:      309.81,  raw= 310  [pixels]
  ROLL:            351.69 [deg]
  GAIN:            2
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   28.32
  GRB_POS_XRT_Z:   -66.03
  IMAGE_URL:       sw00599287000msxps_rw.img
  SUN_POSTN:        55.09d {+03h 40m 22s}  +19.57d {+19d 34' 13"}
  SUN_DIST:        117.66 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.82d {+19h 03m 17s}  -17.55d {-17d 33' 13"}
  MOON_DIST:        80.47 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.65, 58.18 [deg] galactic lon,lat of the burst
  ECL_COORDS:      204.57, 56.57 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Image.  
  COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
  COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
  COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:20:45 UT
  NOTICE_TYPE:     Swift-XRT Processed Image
  TRIGGER_NUM:     599287,   Seg_Num: 0
  GRB_RA:          227.2519d {+15h 09m 00.4s} (J2000),
                   227.3824d {+15h 09m 31.7s} (current),
                   226.7981d {+15h 07m 11.5s} (1950)
  GRB_DEC:         +42.4174d {+42d 25' 02.6"} (J2000),
                   +42.3631d {+42d 21' 47.3"} (current),
                   +42.6072d {+42d 36' 25.8"} (1950)
  GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       106 [cnts]
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33535.02 SOD {09:18:55.02} UT,   46080.2 [sec] since BAT Trigger Time
  CENTROID_X:      277.28,  raw= 277  [pixels]
  CENTROID_Y:      309.81,  raw= 310  [pixels]
  ROLL:            351.69 [deg]
  GAIN:            2
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   28.32
  GRB_POS_XRT_Z:   -66.03
  IMAGE_URL:       sw00599287000msxps_rw.img
  SUN_POSTN:        55.09d {+03h 40m 22s}  +19.57d {+19d 34' 13"}
  SUN_DIST:        117.66 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.82d {+19h 03m 18s}  -17.55d {-17d 33' 12"}
  MOON_DIST:        80.48 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.65, 58.18 [deg] galactic lon,lat of the burst
  ECL_COORDS:      204.57, 56.57 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Processed Image.  
  COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
  COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
  COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:22:20 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     599287,   Seg_Num: 0
  GRB_RA:          227.269d {+15h 09m 05s} (J2000),
                   227.400d {+15h 09m 36s} (current),
                   226.816d {+15h 07m 16s} (1950)
  GRB_DEC:         +42.416d {+42d 24' 56"} (J2000),
                   +42.361d {+42d 21' 41"} (current),
                   +42.605d {+42d 36' 19"} (1950)
  GRB_DATE:        16795 TJD;   138 DOY;   14/05/18
  GRB_TIME:        33466.63 SOD {09:17:46.63} UT
  TRIGGER_INDEX:   146
  GRB_PHI:         -44.02 [deg]
  GRB_THETA:        20.25 [deg]
  DELTA_TIME:      -24.00 [sec]
  TRIGGER_DUR:      [sec],  copy from BAT_POS unavailable
  SOLN_STATUS:     0x0
  RATE_SIGNIF:     0.00 [sigma]
  IMAGE_SIGNIF:    0.00 [sigma]
  LC_URL:          sw00599287000msb.lc
  SUN_POSTN:        55.09d {+03h 40m 22s}  +19.57d {+19d 34' 14"}
  SUN_DIST:        117.66 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.84d {+19h 03m 22s}  -17.55d {-17d 33' 04"}
  MOON_DIST:        80.47 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.64, 58.17 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      204.59, 56.57 [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:     Sun 18 May 14 09:22:59 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.266d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.401d {+42d 24' 03"} (J2000)
  POINT_ROLL:      351.689d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33543.27 SOD {09:19:03.27} UT,   46088.5 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        1.495
  N_STARS:         32
  X_OFFSET:        600 [pixels]
  Y_OFFSET:        528 [pixels]
  X_MAX:           1559 [pixels]
  Y_MAX:           1487 [pixels]
  DET_THRESH:      10
  PHOTO_THRESH:    5
  SL_URL:          sw00599287000msufc132488.fits
  SUN_POSTN:        55.09d {+03h 40m 22s}  +19.57d {+19d 34' 15"}
  SUN_DIST:        117.68 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.85d {+19h 03m 23s}  -17.55d {-17d 33' 01"}
  MOON_DIST:        80.47 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.62, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.56 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:23:41 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.266d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.401d {+42d 24' 03"} (J2000)
  ROLL:            351.689d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33543.27 SOD {09:19:03.27} UT,   46088.5 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     422097555
  X_OFFSET:        900 [pixels]
  Y_OFFSET:        764 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1060
  Y_GRB_POS:       924
  BINNING_INDEX:   1
  IM_URL:          sw00599287000msuni132501.fits
  SUN_POSTN:        55.09d {+03h 40m 22s}  +19.57d {+19d 34' 15"}
  SUN_DIST:        117.68 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.85d {+19h 03m 25s}  -17.55d {-17d 32' 58"}
  MOON_DIST:        80.47 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.62, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.56 [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:     Sun 18 May 14 09:24:43 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.266d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.401d {+42d 24' 03"} (J2000)
  ROLL:            351.689d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33543.27 SOD {09:19:03.27} UT,   46088.5 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     422097555
  X_OFFSET:        900 [pixels]
  Y_OFFSET:        764 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1060
  Y_GRB_POS:       924
  BINNING_INDEX:   1
  IM_URL:          sw00599287000msuni132501.fits
  SUN_POSTN:        55.09d {+03h 40m 23s}  +19.57d {+19d 34' 16"}
  SUN_DIST:        117.68 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.87d {+19h 03m 28s}  -17.55d {-17d 32' 53"}
  MOON_DIST:        80.48 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.62, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.56 [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:     Sun 18 May 14 09:24:57 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.266d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.401d {+42d 24' 03"} (J2000)
  POINT_ROLL:      351.689d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33543.27 SOD {09:19:03.27} UT,   46088.5 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        1.495
  N_STARS:         32
  X_OFFSET:        600 [pixels]
  Y_OFFSET:        528 [pixels]
  X_MAX:           1559 [pixels]
  Y_MAX:           1487 [pixels]
  DET_THRESH:      10
  PHOTO_THRESH:    5
  SL_URL:          sw00599287000msufc132488.fits
  SUN_POSTN:        55.09d {+03h 40m 23s}  +19.57d {+19d 34' 16"}
  SUN_DIST:        117.68 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.87d {+19h 03m 28s}  -17.55d {-17d 32' 52"}
  MOON_DIST:        80.48 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.62, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.56 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:30:11 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.265d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.398d {+42d 23' 55"} (J2000)
  POINT_ROLL:      351.688d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33755.94 SOD {09:22:35.94} UT,   46301.2 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        0.430
  N_STARS:         23
  X_OFFSET:        580 [pixels]
  Y_OFFSET:        444 [pixels]
  X_MAX:           1539 [pixels]
  Y_MAX:           1403 [pixels]
  DET_THRESH:      6
  PHOTO_THRESH:    2
  SL_URL:          sw00599287000msufc132701.fits
  SUN_POSTN:        55.10d {+03h 40m 23s}  +19.57d {+19d 34' 19"}
  SUN_DIST:        117.68 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.92d {+19h 03m 41s}  -17.54d {-17d 32' 27"}
  MOON_DIST:        80.51 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.61, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.55 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:30:32 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.265d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.398d {+42d 23' 55"} (J2000)
  POINT_ROLL:      351.688d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33755.94 SOD {09:22:35.94} UT,   46301.2 [sec] since BAT Trigger Time
  FILTER:          7, U
  BKG_MEAN:        0.430
  N_STARS:         23
  X_OFFSET:        580 [pixels]
  Y_OFFSET:        444 [pixels]
  X_MAX:           1539 [pixels]
  Y_MAX:           1403 [pixels]
  DET_THRESH:      6
  PHOTO_THRESH:    2
  SL_URL:          sw00599287000msufc132701.fits
  SUN_POSTN:        55.10d {+03h 40m 23s}  +19.57d {+19d 34' 19"}
  SUN_DIST:        117.68 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.93d {+19h 03m 42s}  -17.54d {-17d 32' 26"}
  MOON_DIST:        80.51 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.61, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.55 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:31:27 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.265d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.398d {+42d 23' 55"} (J2000)
  ROLL:            351.688d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33755.94 SOD {09:22:35.94} UT,   46301.2 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     422097767
  X_OFFSET:        900 [pixels]
  Y_OFFSET:        764 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1060
  Y_GRB_POS:       924
  BINNING_INDEX:   1
  IM_URL:          sw00599287000msuni132714.fits
  SUN_POSTN:        55.10d {+03h 40m 24s}  +19.57d {+19d 34' 19"}
  SUN_DIST:        117.68 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.94d {+19h 03m 45s}  -17.54d {-17d 32' 21"}
  MOON_DIST:        80.51 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.61, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.55 [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:     Sun 18 May 14 09:31:36 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.265d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.398d {+42d 23' 55"} (J2000)
  ROLL:            351.688d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  33755.94 SOD {09:22:35.94} UT,   46301.2 [sec] since BAT Trigger Time
  FILTER:          7, U
  EXPOSURE_ID:     422097767
  X_OFFSET:        900 [pixels]
  Y_OFFSET:        764 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1060
  Y_GRB_POS:       924
  BINNING_INDEX:   1
  IM_URL:          sw00599287000msuni132714.fits
  SUN_POSTN:        55.10d {+03h 40m 24s}  +19.57d {+19d 34' 19"}
  SUN_DIST:        117.68 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      285.94d {+19h 03m 45s}  -17.54d {-17d 32' 21"}
  MOON_DIST:        80.51 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.61, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.55 [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:     Sun 18 May 14 09:37:31 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.265d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.398d {+42d 23' 55"} (J2000)
  POINT_ROLL:      351.688d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  34333.41 SOD {09:32:13.41} UT,   46878.6 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        1.312
  N_STARS:         72
  X_OFFSET:        340 [pixels]
  Y_OFFSET:        204 [pixels]
  X_MAX:           1779 [pixels]
  Y_MAX:           1643 [pixels]
  DET_THRESH:      10
  PHOTO_THRESH:    5
  SL_URL:          sw00599287000msufc133278.fits
  SUN_POSTN:        55.10d {+03h 40m 25s}  +19.57d {+19d 34' 23"}
  SUN_DIST:        117.68 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      286.00d {+19h 04m 00s}  -17.53d {-17d 31' 53"}
  MOON_DIST:        80.55 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.61, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.55 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:37:47 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.265d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.398d {+42d 23' 55"} (J2000)
  POINT_ROLL:      351.688d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  34333.41 SOD {09:32:13.41} UT,   46878.6 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        1.312
  N_STARS:         72
  X_OFFSET:        340 [pixels]
  Y_OFFSET:        204 [pixels]
  X_MAX:           1779 [pixels]
  Y_MAX:           1643 [pixels]
  DET_THRESH:      10
  PHOTO_THRESH:    5
  SL_URL:          sw00599287000msufc133278.fits
  SUN_POSTN:        55.10d {+03h 40m 25s}  +19.57d {+19d 34' 23"}
  SUN_DIST:        117.67 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      286.00d {+19h 04m 00s}  -17.53d {-17d 31' 51"}
  MOON_DIST:        80.55 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.61, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.55 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:38:45 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.265d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.398d {+42d 23' 55"} (J2000)
  ROLL:            351.688d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  34333.41 SOD {09:32:13.41} UT,   46878.6 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     422098345
  X_OFFSET:        899 [pixels]
  Y_OFFSET:        763 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1059
  Y_GRB_POS:       923
  BINNING_INDEX:   1
  IM_URL:          sw00599287000msuni133291.fits
  SUN_POSTN:        55.10d {+03h 40m 25s}  +19.57d {+19d 34' 23"}
  SUN_DIST:        117.67 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      286.01d {+19h 04m 03s}  -17.53d {-17d 31' 47"}
  MOON_DIST:        80.55 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.61, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.55 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Image.  
  COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
  COMMENTS:        The image has 2x2 binning (compression).  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 18 May 14 09:39:05 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     599287,   Seg_Num: 0
  POINT_RA:        227.265d {+15h 09m 04s} (J2000)
  POINT_DEC:       +42.398d {+42d 23' 55"} (J2000)
  ROLL:            351.688d
  IMG_START_DATE:  16795 TJD;   138 DOY;   14/05/18
  IMG_START_TIME:  34333.41 SOD {09:32:13.41} UT,   46878.6 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     422098345
  X_OFFSET:        899 [pixels]
  Y_OFFSET:        763 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1059
  Y_GRB_POS:       923
  BINNING_INDEX:   1
  IM_URL:          sw00599287000msuni133291.fits
  SUN_POSTN:        55.10d {+03h 40m 25s}  +19.57d {+19d 34' 23"}
  SUN_DIST:        117.67 [deg]   Sun_angle= -11.5 [hr] (East of Sun)
  MOON_POSTN:      286.01d {+19h 04m 04s}  -17.53d {-17d 31' 45"}
  MOON_DIST:        80.55 [deg]
  MOON_ILLUM:      84 [%]
  GAL_COORDS:       70.61, 58.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      204.60, 56.55 [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 #16298
  A. Melandri (INAF-OAB), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D. Malesani (DARK/NBI), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team:
  At 09:17:46 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140518A (trigger=599287). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 227.269, +42.416 which is

     RA(J2000) = 15h 09m 05s
     Dec(J2000) = +42d 24' 56"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a multiple-peaked structure with a duration of about 60 s. The peak count rate was ~1500 counts/s (15-350 keV) at ~0 sec after trigger.
  The XRT began observing the field at 09:18:55.0 UT, 69 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source with an enhanced position: RA, Dec 227.2519, 42.4185 which is equivalent to:

     RA(J2000)  = 15h 09m 00.45s
     Dec(J2000) = +42d 25' 06.6"
  

  with an uncertainty of 2.0 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 in excess of the Galactic value (1.56 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.5 (+2.30/-2.03) x 10^21 cm^-2 (90% confidence).
  The initial flux in the 2.5 s image was 3.67e-09 erg cm^-2 s^-1 (0.2-10 keV).
  UVOT took a finding chart exposure of 150 seconds with the White filter starting 76 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 0.02.
  Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.it). 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 #16299
  WeiKang Zheng, Alexei V. Filippenko, Adam Morgan (UC Berkeley), and S. B. Cenko (NASA/Goddard Space Flight Center) report on behalf of the KAIT GRB team:
  The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to GRB 140518A (Swift trigger 599287; Melandri et al., GCN 16298) starting at 09:22:16 UT, 270 s after the burst. Observations were performed with an automatic sequence in the clear (roughly R), V and I filters, and the exposure time was 20 s per image. We detect a faint object within XRT error circle at J2000 coordinates of:

  RA =  15:09:00.62
  DEC= +42:25:05.9
  

  with uncertainty of about 1". The object was only detected in the first clear band single image with mag R~18.3, no detection in following single images. But it is marginally detected in the co-add of next 5 single images with mag R~19.0. We suggest this to be the afterglow of the GRB. All mags are calibrated to USNO B1.0 catalog.
• GCN Circular #16300
  D. A. Perley (Caltech) reports on behalf of a larger collaboration
  The Palomar 60-inch telescope responded automatically to the Swift trigger for GRB 140518A (Melandri et al., GCN 16298) and began a repeating cycle of 60-second exposures in r, i, and z-band observations at 09:22:28 UT, 4.70 minutes after the burst.
  We weakly detect the afterglow reported by Zheng et al. (GCN 16299) in the i and z filters, but not in r-band. Only marginal detections are evident in any individual exposure in any filter, but a stack of the first six exposures in each band gives magnitudes (calibrated relative to SDSS) of:

  r > 20.31  (2 sigma)
  i = 19.03 +/- 0.16
  z = 18.20 +/- 0.17
  

  at a mid-time of approximately 16 minutes after the burst.
• GCN Circular #16301
  R. Chornock (Harvard), D. B. Fox (Penn State), A. Cucchiara (Goddard), D. A. Perley (Caltech), and A. Levan (Warwick) report on behalf of a larger collaboration:
  We obtained 2x900s of spectroscopy of the optical afterglow (Zheng et al., GCN 16299; Perley et al., GCN 16300) of GRB140518A (Melandri et al., GCN 16298) using GMOS on the 8-m Gemini-North telescope starting at 12:22 UT on May 18. Our spectra covered the wavelength range 5900-10150 Angstroms at a resolution of R~1200. A damped Lyman-alpha system is present near 6940 Angs, corresponding to z~4.71. A fit to the absorber gives z=4.706 and the log of the HI column density (in cm^-2) is 21.65 +- 0.1. Strong narrow absorption lines of S II, Si II, Si II*, O I, O I*, Si IV, C II, C IV, Fe II, and Al II associated with this absorption system have a common redshift of z=4.707. The combination of the DLA and the excited fine structure lines allow us to identify this as the redshift of the GRB.
  We thank the Gemini staff, in particular Rachel Mason and Joy Chavez, for their assistance with these observations.
• GCN Circular #16302
  A. Cucchiara (NASA/GSFC), 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),=20 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 140518A (Melandri, et al., GCN 16298) 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 2014/05 18.41 to 2014/05 18.46 UTC (9.90 to 11.05 hours after the BAT trigger), obtaining a total of 0.71 hours exposure in the r and i bands and 0.30 hours exposure in the Z, Y, J, and H bands.
  We detect the fading source identified by Zheng et al. (GCN 16299) and Perley et al. (GCN 16300) within the Swift-XRT error circle. We confirm this to be the optical afterglow of GRB 140518A.
  In comparison with the SDSS DR9 and 2MASS, we obtain the following detections:

    r	20.50 +/- 0.04
    i	19.00 +/- 0.02
    Z	18.59 +/- 0.03
    Y	18.19 +/- 0.03
    J	18.13 +/- 0.02
    H	17.80 +/- 0.02
  

  These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Based on these observations, and using our automatic photo-z analysis tool (Littlejohns et al. arXiv:1312.3967) we determine two possible photometric redshifts: assuming a Milky Way extinction curve for the GRB host we derive a photo-z of z=3D1.88 (+- 0.06) and A_V=3D1.8, while a SMC extinction law gives a z=3D4.63 (+- 0.11) and A_V=3D0.5.=20 The second solution is consistent with the spectroscopic redshift reported by Chornock et al. (GCN 16301).
  We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
• GCN Circular #16303
  N. P. M. Kuin (UCL-MSSL) and A. Melandri (INAF-OAB) report on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 140518A 77 s after the BAT trigger (Melandri et al., GCN Circ. 16298). No optical afterglow consistent with the XRT position (Melandri et al. GCN Circ. 16298) 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            77          226          147         >20.7
  u_FC               289          539          246         >20.7
  white               77        13719         1583         >22.6
  v                  619         7499          568         >20.2
  b                  545        12953         1060         >22.0
  u                  289        12041         1286         >21.6
  w1                 668         7910          568         >21.4
  m2                1071         7705          413         >21.1
  w2                 595         7295          510         >21.3
  

  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).
• GCN Circular #16304
  A. Trotter, A. LaCluyze, J. Haislip, D. Reichart, K. McLin, L. Cominsky, H. T. Cromartie, A. Foster, N. Frank, K. Ivarsen, M. Maples, J. Moore, M. Nysewander, R. Beauchemin, T. Berger, A. Dow, M. Hinckle, A. Patterson, H. Pegues, J. Pozo, D. Waddell, and J. A. Crain report:
  Skynet observed the Swift-XRT localization of GRB 140518A (Melandri et al., GCN 16298, Swift trigger 599287) with the 14" GLAST Optical Robotic Telescope (GORT) at the Hume observatory in CA, USA. Observations began at t=130s and continued until 2.4h post-trigger. Skynet took alternating exposures in the Rc and Ic bands, increasing from 10s to 160s. In early Ic and Rc images, and in later stacked Ic images, we detect an uncatalogued fading optical source at a position consistent with the afterglow candidate reported by Zheng et al. (GCN 16299).
  The source faded from Ic=16.8 at t=130s to Ic > 18.7 at a mean time t~70m. In Rc band, we detect the source marginally at Rc~18.3 at t=4m, with Rc>20.1 at a mean time t~55m.
  A preliminary light curve is at: http://www.skynet.unc.edu/grb/grb140518a.png
  Photometry is calibrated to six APASS-DR7 stars in the field, and has not been corrected for the Galactic foreground extinction corresponding to E(B-V)=0.016 (Schlegel et al. 1998).
  No further Skynet observations are scheduled.
  
• GCN Circular #16305
  A. Maselli (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), V. Mangano (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) and A. Melandri report on behalf of the Swift-XRT team:
  We have analysed 8.3 ks of XRT data for GRB 140518A (Melandri et al. GCN Circ. 16298), from 58 s to 19.5 ks after the BAT trigger. The data comprise 92 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. Using 4543 s of PC mode data and 6 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 227.25249, +42.41821 which is equivalent to:

  RA (J2000): 15h 09m 00.60s
  Dec(J2000): +42d 25' 05.6"
  

  with an uncertainty of 1.5 arcsec (radius, 90% confidence).
  The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=3.42 (+0.22, -0.19). At T+251 s the decay flattens to an alpha of 0.25 (+0.15, -0.18) before breaking again at T+2747 s to a final decay with index alpha=1.51 (+0.32, -0.27).
  A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.66 (+/-0.10). The best-fitting absorption column is 2.5 (+1.7, -1.6) x 10^22 cm^-2, at a redshift of 4.707, in addition to the Galactic value of 1.6 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.94 (+/-0.12) and a best-fitting absorption column of 2.9 (+1.7, -1.6) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1.
  A summary of the PC-mode spectrum is thus:

  Galactic foreground: 1.6 x 10^20 cm^-2
  Intrinsic column:    2.9 (+1.7, -1.6) x 10^22 cm^-2 at z=4.707
  Photon index:	     1.94 (+/-0.12)
  

  If the light curve continues to decay with a power-law decay index of 1.51, the count rate at T+24 hours will be 2.0 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.9 x 10^-14 (7.8 x 10^-14) erg cm^-2 s^-1.
  The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00599287.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #16306
  T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC) (i.e. the Swift-BAT team):
  Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 140518A (trigger #599287) (Melandri, et al., GCN Circ. 16298). The BAT ground-calculated position is RA, Dec = 227.231, 42.396 deg which is

    RA(J2000)  =  15h 08m 55.3s
    Dec(J2000) = +42d 23' 44.2"
  

  with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 89%.
  The mask-weighted light curve shows multiple peaks with roughly three main pulse structures. The first main pulse starts at ~T-4 s and ends at ~T+8 s. The second main pulse starts at ~T+38 s, followed immediately by the third main pulse structure that starts at ~T+48 s and ends at ~T+61 s. Additionally, each of these main pulse structure contains several sub-pulses. T90 (15-350 keV) is 60.5 +- 2.4 sec (estimated error including systematics).
  The time-averaged spectrum from T-4.1 to T+60.0 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.92 +- 0.61, and Epeak of 43.9 +- 7.6 keV (chi squared 54.15 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+41.94 sec in the 15-150 keV band is 1.0 +- 0.1 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.97 +- 0.13 (chi squared 65.02 for 57 d.o.f.). 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/599287/BA/
• GCN Circular #16308
  Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia= m 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=C3=A9 A. de Diego (UNAM), Leonid Georgiev (UNAM)= , Jes=C3=BAs Gonz=C3=A1lez (UNAM), Carlos Rom=C3=A1n-Z=C3=BA=C3=B1iga (UNAM), Neil Geh= rels (GSFC), and Harvey Moseley (GSFC) report:
  We observed the field of GRB 140518A (Melandri, et al., GCN 16298) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=C3=B3mico Nacional on Sierra San Pedro M=C3=A1rtir from 2014/05 19.24 to 2014/05 19.46 UTC (20.37 to 25.71 hours after the BAT trigger), obtaining a total of 2.47 hours exposure in the r and i bands and 2.06 hours exposure in the Z an J bands.
  For a source at the optical transient position (Zheng et al., GCN 16299), in comparison with the SDSS DR9 and 2MASS, we obtain the following upper limits (3-sigma):

    r  > 22.03
    i  > 22.20
    Z  > 21.28
    J  > 21.07
  

  These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Compared to our observations last night (Cucchiara, et al., GCN 16302), during which the source faded approximately as t^(-0.5), the source has now apparently faded more rapidly as t^(-1) or faster.
  We thank the staff of the Observatorio Astron=C3=B3mico Nacional in San Pedro M=C3=A1rtir.
• GCN Circular #16309
  E. Sonbas (Adiyaman Univ.), T. Guver (Istanbul Univ.), U. Temiz, F.Dolek (Cukurova Univ.), E. Gogus (Sabanci Univ.), O. Erece (Akdeniz Univ.), O. Basturk (Ankara Univ.) report on behalf of a larger collaboration
  We observed the field of Swift GRB 140518A (Melandri et al., GCN#16298) with the 1.0 meter T100 telescope (Bakirlitepe, TUBITAK National Observatory, Turkey), starting May, 18, 21:35:41 UT (~ 12.3 hours after the trigger). 5 x 300 s exposures were obtained in the R filter under moderate weather conditions.
  We do not detect an optical afterglow within the reported XRT error circle down to a limiting magnitude of >20.37 (2-sigma) in the combined R band image.
  We are grateful to TUBITAK National Observatory for prompt scheduling the observations and technical support.