Gamma-ray Burst 180828A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 18:57:55 UT
  NOTICE_TYPE:     Swift-BAT GRB Position 
  TRIGGER_NUM:     856977,   Seg_Num: 0   
  GRB_RA:          268.700d {+17h 54m 48s} (J2000),
                   268.989d {+17h 55m 57s} (current),
                   267.925d {+17h 51m 42s} (1950)
  GRB_DEC:         -25.800d {-25d 47' 58"} (J2000),
                   -25.802d {-25d 48' 05"} (current),
                   -25.792d {-25d 47' 28"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       15281 [cnts]    Image_Peak=758 [image_cnts]
  TRIGGER_DUR:     1.024 [sec]    
  TRIGGER_INDEX:   155     E_range: 50-350 keV
  BKG_INTEN:       36379 [cnts]
  BKG_TIME:        68242.49 SOD {18:57:22.49} UT
  BKG_DUR:         8 [sec] 
  GRB_DATE:        18358 TJD;   240 DOY;   18/08/28
  GRB_TIME:        68254.78 SOD {18:57:34.78} UT
  GRB_PHI:          -7.39 [deg]
  GRB_THETA:        53.36 [deg]
  SOLN_STATUS:     0x20000103  
  RATE_SIGNIF:     120.68 [sigma]
  IMAGE_SIGNIF:    16.50 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +0  +3  +5  +0  +1 +39  +0
  SUN_POSTN:       157.24d {+10h 28m 56s}   +9.52d {+09d 31' 18"}
  SUN_DIST:        113.65 [deg]   Sun_angle= -7.5 [hr] (East of Sun)
  MOON_POSTN:        2.97d {+00h 11m 54s}   -3.38d {-03d 22' 31"}
  MOON_DIST:        92.11 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.74, -0.14 [deg] galactic lon,lat of the burst (or transient)      
  ECL_COORDS:      268.83, -2.37 [deg] ecliptic lon,lat of the burst (or transient)      
  COMMENTS:        SWIFT-BAT GRB Coordinates.
  COMMENTS:        This is a rate trigger. 
  COMMENTS:        A point_source was found.
  COMMENTS:        This does not match any source in the on-board catalog.
  COMMENTS:        This matches a source in the ground catalog: SwJ1753.7-2544, delta=0.251 [deg].
  COMMENTS:        This is not a GRB.
  COMMENTS:        This trigger occurred at longitude,latitude = 75.77,8.24 [deg].
  COMMENTS:        
  COMMENTS:        NOTE: This BAT event is temporally(8.0<100sec) coincident with the FERMI_GBM event (trignum=557175451).
  

• GCN NOTICE
  

  TITLE:           GCN/FERMI NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 18:57:50 UT
  NOTICE_TYPE:     Fermi-GBM Flight Position
  RECORD_NUM:      47
  TRIGGER_NUM:     557175451
  GRB_RA:          264.800d {+17h 39m 12s} (J2000),
                   265.055d {+17h 40m 13s} (current),
                   264.116d {+17h 36m 28s} (1950)
  GRB_DEC:          -8.850d {-08d 50' 59"} (J2000),
                    -8.859d {-08d 51' 32"} (current),
                    -8.823d {-08d 49' 22"} (1950)
  GRB_ERROR:       8.95 [deg radius, statistical plus systematic]
  GRB_INTEN:       1084 [cnts/sec]
  DATA_SIGNIF:     14.00 [sigma]
  INTEG_TIME:      0.128 [sec]
  GRB_DATE:        18358 TJD;   240 DOY;   18/08/28
  GRB_TIME:        68246.58 SOD {18:57:26.58} UT
  GRB_PHI:         115.98 [deg]
  GRB_THETA:        60.00 [deg]
  DATA_TIME_SCALE: 0.1280 [sec]
  HARD_RATIO:      0.31
  LOC_ALGORITHM:   3 (version number of)
  MOST_LIKELY:      93%  GRB
  2nd_MOST_LIKELY:   3%  SGR_1806n20
  DETECTORS:       0,0,0, 0,0,0, 0,0,0, 1,1,1, 0,0,
  SUN_POSTN:       157.24d {+10h 28m 56s}   +9.52d {+09d 31' 18"}
  SUN_DIST:        108.89 [deg]   Sun_angle= -7.2 [hr] (East of Sun)
  MOON_POSTN:        2.97d {+00h 11m 54s}   -3.38d {-03d 22' 32"}
  MOON_DIST:        97.29 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:       16.53, 11.68 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      264.69, 14.49 [deg] ecliptic lon,lat of the burst (or transient)
  LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180828790/quicklook/glg_lc_medres34_bn180828790.gif
  COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
  COMMENTS:        This trigger occurred at longitude,latitude = 15.73,5.73 [deg].  
  COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
  

• GCN NOTICE
  

  TITLE:           GCN/FERMI NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 18:57:59 UT
  NOTICE_TYPE:     Fermi-GBM Flight Position
  RECORD_NUM:      59
  TRIGGER_NUM:     557175451
  GRB_RA:          264.933d {+17h 39m 44s} (J2000),
                   265.188d {+17h 40m 45s} (current),
                   264.250d {+17h 37m 00s} (1950)
  GRB_DEC:          -8.717d {-08d 43' 00"} (J2000),
                    -8.726d {-08d 43' 31"} (current),
                    -8.690d {-08d 41' 25"} (1950)
  GRB_ERROR:       4.48 [deg radius, statistical plus systematic]
  GRB_INTEN:       2207 [cnts/sec]
  DATA_SIGNIF:     128.20 [sigma]
  INTEG_TIME:      2.048 [sec]
  GRB_DATE:        18358 TJD;   240 DOY;   18/08/28
  GRB_TIME:        68246.58 SOD {18:57:26.58} UT
  GRB_PHI:         115.98 [deg]
  GRB_THETA:        60.00 [deg]
  DATA_TIME_SCALE: 2.0480 [sec]
  HARD_RATIO:      0.36
  LOC_ALGORITHM:   3 (version number of)
  MOST_LIKELY:      92%  GRB
  2nd_MOST_LIKELY:   4%  SGR_1806n20
  DETECTORS:       0,0,0, 0,0,0, 0,0,0, 1,1,1, 0,0,
  SUN_POSTN:       157.24d {+10h 28m 56s}   +9.52d {+09d 31' 18"}
  SUN_DIST:        109.00 [deg]   Sun_angle= -7.2 [hr] (East of Sun)
  MOON_POSTN:        2.97d {+00h 11m 54s}   -3.38d {-03d 22' 30"}
  MOON_DIST:        97.17 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:       16.71, 11.63 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      264.82, 14.63 [deg] ecliptic lon,lat of the burst (or transient)
  LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180828790/quicklook/glg_lc_medres34_bn180828790.gif
  COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
  COMMENTS:        This trigger occurred at longitude,latitude = 15.73,5.73 [deg].  
  COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
  COMMENTS:           
  COMMENTS:        NOTE: This GBM event is temporally(8.0<100sec) coincident with the SWIFT_BAT event (trignum=856977).  
  

• GCN NOTICE
  

  TITLE:           GCN/FERMI NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 18:58:03 UT
  NOTICE_TYPE:     Fermi-GBM Ground Position
  RECORD_NUM:      58
  TRIGGER_NUM:     557175451
  GRB_RA:          270.970d {+18h 03m 53s} (J2000),
                   271.257d {+18h 05m 02s} (current),
                   270.200d {+18h 00m 48s} (1950)
  GRB_DEC:         -24.890d {-24d 53' 23"} (J2000),
                   -24.888d {-24d 53' 16"} (current),
                   -24.893d {-24d 53' 33"} (1950)
  GRB_ERROR:       1.20 [deg radius, statistical only]
  DATA_SIGNIF:     57.20 [sigma]
  DATA_INTERVAL:   2.048 [sec]
  GRB_DATE:        18358 TJD;   240 DOY;   18/08/28
  GRB_TIME:        68246.58 SOD {18:57:26.58} UT
  GRB_PHI:         118.00 [deg]
  GRB_THETA:        77.00 [deg]
  E_RANGE:         44.032 - 279.965 [keV]
  LOC_ALGORITHM:   4153 (Gnd S/W Version number)
  SUN_POSTN:       157.24d {+10h 28m 57s}   +9.52d {+09d 31' 18"}
  SUN_DIST:        115.71 [deg]   Sun_angle= -7.6 [hr] (East of Sun)
  MOON_POSTN:        2.98d {+00h 11m 54s}   -3.38d {-03d 22' 29"}
  MOON_DIST:        90.14 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        5.55, -1.47 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      270.88, -1.45 [deg] ecliptic lon,lat of the burst (or transient)
  LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180828790/quicklook/glg_lc_medres34_bn180828790.gif
  POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_557175451.fits
  COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
  COMMENTS:        Bright hard burst in the GBM.  
  COMMENTS:        This Notice was ground-generated -- not flight-generated.  
  COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
  COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.  
  COMMENTS:           
  COMMENTS:        NOTE: This GBM event is temporally(8.0<100sec) coincident with the SWIFT_BAT event (trignum=856977).  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 18:59:57 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     856977,   Seg_Num: 0
  GRB_RA:          268.7184d {+17h 54m 52.41s} (J2000),
                   269.0076d {+17h 56m 01.83s} (current),
                   267.9434d {+17h 51m 46.41s} (1950)
  GRB_DEC:         -25.7991d {-25d 47' 56.7"} (J2000),
                   -25.8012d {-25d 48' 04.1"} (current),
                   -25.7910d {-25d 47' 27.5"} (1950)
  GRB_ERROR:       5.8 [arcsec radius, statistical plus systematic, 90% containment]
  GRB_INTEN:       7.99e-10 [erg/cm2/sec]
  GRB_SIGNIF:      5.19 [sigma]
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  68370.38 SOD {18:59:30.38} UT,   115.6 [sec] since BAT Trigger Time
  TAM[0-3]:        327.67 237.14 261.68 243.66
  AMPLIFIER:       2
  WAVEFORM:        134
  SUN_POSTN:       157.24d {+10h 28m 57s}   +9.52d {+09d 31' 16"}
  SUN_DIST:        113.66 [deg]   Sun_angle= -7.5 [hr] (East of Sun)
  MOON_POSTN:        2.99d {+00h 11m 58s}   -3.37d {-03d 22' 09"}
  MOON_DIST:        92.11 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.75, -0.15 [deg] galactic lon,lat of the burst
  ECL_COORDS:      268.85, -2.36 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Coordinates.  
  COMMENTS:        This matches a source in the BAT ground catalog: SwJ1753.7-2544,   delta=0.267 [deg].  
  COMMENTS:        The XRT position is 1.00 arcmin from the BAT position.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 19:00:07 UT
  NOTICE_TYPE:     Swift-XRT Image
  TRIGGER_NUM:     856977,   Seg_Num: 0
  GRB_RA:          268.7184d {+17h 54m 52.4s} (J2000),
                   269.0076d {+17h 56m 01.8s} (current),
                   267.9434d {+17h 51m 46.4s} (1950)
  GRB_DEC:         -25.7991d {-25d 47' 56.7"} (J2000),
                   -25.8012d {-25d 48' 04.1"} (current),
                   -25.7910d {-25d 47' 27.5"} (1950)
  GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       27 [cnts]
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  68370.38 SOD {18:59:30.38} UT,   115.6 [sec] since BAT Trigger Time
  CENTROID_X:      286.08,  raw= 286  [pixels]
  CENTROID_Y:      279.12,  raw= 279  [pixels]
  ROLL:            269.46 [deg]
  GAIN:            1
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   -45.43
  GRB_POS_XRT_Z:   -47.87
  IMAGE_URL:       sw00856977000msxps_rw.img
  SUN_POSTN:       157.24d {+10h 28m 57s}   +9.52d {+09d 31' 16"}
  SUN_DIST:        113.66 [deg]   Sun_angle= -7.5 [hr] (East of Sun)
  MOON_POSTN:        2.99d {+00h 11m 58s}   -3.37d {-03d 22' 07"}
  MOON_DIST:        92.11 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.75, -0.15 [deg] galactic lon,lat of the burst
  ECL_COORDS:      268.85, -2.36 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Image.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 19:00:10 UT
  NOTICE_TYPE:     Swift-XRT Processed Image
  TRIGGER_NUM:     856977,   Seg_Num: 0
  GRB_RA:          268.7184d {+17h 54m 52.4s} (J2000),
                   269.0076d {+17h 56m 01.8s} (current),
                   267.9434d {+17h 51m 46.4s} (1950)
  GRB_DEC:         -25.7991d {-25d 47' 56.7"} (J2000),
                   -25.8012d {-25d 48' 04.1"} (current),
                   -25.7910d {-25d 47' 27.5"} (1950)
  GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
  GRB_INTEN:       27 [cnts]
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  68370.38 SOD {18:59:30.38} UT,   115.6 [sec] since BAT Trigger Time
  CENTROID_X:      286.08,  raw= 286  [pixels]
  CENTROID_Y:      279.12,  raw= 279  [pixels]
  ROLL:            269.46 [deg]
  GAIN:            1
  MODE:            3, Long Image mode
  WAVEFORM:        134
  EXPO_TIME:       2.50 [sec]
  GRB_POS_XRT_Y:   -45.43
  GRB_POS_XRT_Z:   -47.87
  IMAGE_URL:       sw00856977000msxps_rw.img
  SUN_POSTN:       157.24d {+10h 28m 57s}   +9.52d {+09d 31' 16"}
  SUN_DIST:        113.66 [deg]   Sun_angle= -7.5 [hr] (East of Sun)
  MOON_POSTN:        2.99d {+00h 11m 58s}   -3.37d {-03d 22' 06"}
  MOON_DIST:        92.11 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.75, -0.15 [deg] galactic lon,lat of the burst
  ECL_COORDS:      268.85, -2.36 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Processed Image.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 19:01:00 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     856977,   Seg_Num: 0
  POINT_RA:        268.733d {+17h 54m 56s} (J2000)
  POINT_DEC:       -25.811d {-25d 48' 40"} (J2000)
  POINT_ROLL:      269.464d
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  68378.71 SOD {18:59:38.71} UT,   123.9 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        0.922
  N_STARS:         181
  X_OFFSET:        712 [pixels]
  Y_OFFSET:        528 [pixels]
  X_MAX:           1671 [pixels]
  Y_MAX:           1487 [pixels]
  DET_THRESH:      8
  PHOTO_THRESH:    4
  SL_URL:          sw00856977000msufc0123.fits
  SUN_POSTN:       157.24d {+10h 28m 57s}   +9.52d {+09d 31' 15"}
  SUN_DIST:        113.67 [deg]   Sun_angle= -7.5 [hr] (East of Sun)
  MOON_POSTN:        3.00d {+00h 12m 00s}   -3.37d {-03d 21' 57"}
  MOON_DIST:        92.11 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.74, -0.17 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      268.86, -2.38 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 19:01:19 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     856977,   Seg_Num: 0
  POINT_RA:        268.733d {+17h 54m 56s} (J2000)
  POINT_DEC:       -25.811d {-25d 48' 40"} (J2000)
  POINT_ROLL:      269.464d
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  68378.71 SOD {18:59:38.71} UT,   123.9 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        0.922
  N_STARS:         181
  X_OFFSET:        712 [pixels]
  Y_OFFSET:        528 [pixels]
  X_MAX:           1671 [pixels]
  Y_MAX:           1487 [pixels]
  DET_THRESH:      8
  PHOTO_THRESH:    4
  SL_URL:          sw00856977000msufc0123.fits
  SUN_POSTN:       157.24d {+10h 28m 57s}   +9.52d {+09d 31' 15"}
  SUN_DIST:        113.67 [deg]   Sun_angle= -7.5 [hr] (East of Sun)
  MOON_POSTN:        3.00d {+00h 12m 00s}   -3.37d {-03d 21' 54"}
  MOON_DIST:        92.11 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.74, -0.17 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      268.86, -2.38 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  COMMENTS:        If you have elected to receive attachments:  
  COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 19:02:10 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     856977,   Seg_Num: 0
  POINT_RA:        268.733d {+17h 54m 56s} (J2000)
  POINT_DEC:       -25.811d {-25d 48' 40"} (J2000)
  ROLL:            269.464d
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  68378.71 SOD {18:59:38.71} UT,   123.9 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     557175600
  X_OFFSET:        934 [pixels]
  Y_OFFSET:        906 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1094
  Y_GRB_POS:       1066
  BINNING_INDEX:   1
  IM_URL:          sw00856977000msuni0145.fits
  SUN_POSTN:       157.24d {+10h 28m 57s}   +9.52d {+09d 31' 14"}
  SUN_DIST:        113.67 [deg]   Sun_angle= -7.5 [hr] (East of Sun)
  MOON_POSTN:        3.01d {+00h 12m 02s}   -3.36d {-03d 21' 45"}
  MOON_DIST:        92.12 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.74, -0.17 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      268.86, -2.38 [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:     Tue 28 Aug 18 19:02:26 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     856977,   Seg_Num: 0
  POINT_RA:        268.733d {+17h 54m 56s} (J2000)
  POINT_DEC:       -25.811d {-25d 48' 40"} (J2000)
  ROLL:            269.464d
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  68378.71 SOD {18:59:38.71} UT,   123.9 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     557175600
  X_OFFSET:        934 [pixels]
  Y_OFFSET:        906 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1094
  Y_GRB_POS:       1066
  BINNING_INDEX:   1
  IM_URL:          sw00856977000msuni0145.fits
  SUN_POSTN:       157.24d {+10h 28m 57s}   +9.52d {+09d 31' 14"}
  SUN_DIST:        113.67 [deg]   Sun_angle= -7.5 [hr] (East of Sun)
  MOON_POSTN:        3.01d {+00h 12m 03s}   -3.36d {-03d 21' 42"}
  MOON_DIST:        92.12 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.74, -0.17 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      268.86, -2.38 [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 #23182
  A. P. Beardmore (U Leicester), S. W. K Emery (UCL-MSSL), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), S. J. LaPorte (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
  At 18:57:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source which is either GRB 180828A or a previously-unknown Galactic transient (trigger=856977). Swift slewed immediately to the source location. The BAT on-board calculated location is RA, Dec 268.700, -25.800 which is

     RA(J2000) = 17h 54m 48s
     Dec(J2000) = -25d 47' 58"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 15 sec. The peak count rate was ~20,000 counts/sec (15-350 keV), at ~0 sec after the trigger.
  The XRT began observing the field at 18:59:30.3 UT, 115.6 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 268.7184, -25.7991 which is equivalent to:

     RA(J2000)  = 17h 54m 52.42s
     Dec(J2000) = -25d 47' 56.8"
  

  with an uncertainty of 5.8 arcseconds (radius, 90% containment). No event data are yet available to determine the column density using X-ray spectroscopy.
  UVOT took a finding chart exposure of 30 seconds with the White filter starting 123 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. Results from the list of sources generated on-board are not available at this time. No correction has been made for the large, but uncertain, extinction expected.
  Due to its location in the Galactic Bulge (3.8 degrees from Sgr A*, 0.14 degrees below the plane), this trigger may be due to a previously unknown X-ray transient. If this source is an X-ray transient, we name it Swift J1754.9-2548. Although the initial GCN Notice identified this as possibly related to Swift J1753.7-2544, the XRT position of this transient is 16.5 arcmin away from Swift J1753.7-2544, and therefore it is unrelated.
  Burst Advocate for this burst is A. P. Beardmore (apb 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:     Tue 28 Aug 18 20:06:32 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     856977,   Seg_Num: 0
  POINT_RA:        268.680d {+17h 54m 43s} (J2000)
  POINT_DEC:       -25.793d {-25d 47' 35"} (J2000)
  POINT_ROLL:      269.499d
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  71615.05 SOD {19:53:35.05} UT,   3360.3 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        1.316
  N_STARS:         96
  X_OFFSET:        216 [pixels]
  Y_OFFSET:        639 [pixels]
  X_MAX:           1175 [pixels]
  Y_MAX:           1598 [pixels]
  DET_THRESH:      10
  PHOTO_THRESH:    5
  SL_URL:          sw00856977000msufc3360.fits
  SUN_POSTN:       157.28d {+10h 29m 07s}   +9.50d {+09d 30' 17"}
  SUN_DIST:        113.58 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
  MOON_POSTN:        3.53d {+00h 14m 07s}   -3.17d {-03d 10' 09"}
  MOON_DIST:        92.72 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.73, -0.12 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      268.81, -2.36 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 20:06:50 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     856977,   Seg_Num: 0
  POINT_RA:        268.680d {+17h 54m 43s} (J2000)
  POINT_DEC:       -25.793d {-25d 47' 35"} (J2000)
  POINT_ROLL:      269.499d
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  71615.05 SOD {19:53:35.05} UT,   3360.3 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        1.316
  N_STARS:         96
  X_OFFSET:        216 [pixels]
  Y_OFFSET:        639 [pixels]
  X_MAX:           1175 [pixels]
  Y_MAX:           1598 [pixels]
  DET_THRESH:      10
  PHOTO_THRESH:    5
  SL_URL:          sw00856977000msufc3360.fits
  SUN_POSTN:       157.28d {+10h 29m 07s}   +9.50d {+09d 30' 17"}
  SUN_DIST:        113.58 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
  MOON_POSTN:        3.53d {+00h 14m 08s}   -3.17d {-03d 10' 06"}
  MOON_DIST:        92.72 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.73, -0.12 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      268.81, -2.36 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  COMMENTS:        If you have elected to receive attachments:  
  COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Tue 28 Aug 18 20:07:55 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     856977,   Seg_Num: 0
  POINT_RA:        268.680d {+17h 54m 43s} (J2000)
  POINT_DEC:       -25.793d {-25d 47' 35"} (J2000)
  ROLL:            269.499d
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  71615.05 SOD {19:53:35.05} UT,   3360.3 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     557178836
  X_OFFSET:        535 [pixels]
  Y_OFFSET:        958 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       695
  Y_GRB_POS:       1118
  BINNING_INDEX:   1
  IM_URL:          sw00856977000msuni3382.fits
  SUN_POSTN:       157.28d {+10h 29m 07s}   +9.50d {+09d 30' 16"}
  SUN_DIST:        113.58 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
  MOON_POSTN:        3.54d {+00h 14m 10s}   -3.17d {-03d 09' 54"}
  MOON_DIST:        92.73 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.73, -0.12 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      268.81, -2.36 [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:     Tue 28 Aug 18 20:08:05 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     856977,   Seg_Num: 0
  POINT_RA:        268.680d {+17h 54m 43s} (J2000)
  POINT_DEC:       -25.793d {-25d 47' 35"} (J2000)
  ROLL:            269.499d
  IMG_START_DATE:  18358 TJD;   240 DOY;   18/08/28
  IMG_START_TIME:  71615.05 SOD {19:53:35.05} UT,   3360.3 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     557178836
  X_OFFSET:        535 [pixels]
  Y_OFFSET:        958 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       695
  Y_GRB_POS:       1118
  BINNING_INDEX:   1
  IM_URL:          sw00856977000msuni3382.fits
  SUN_POSTN:       157.28d {+10h 29m 07s}   +9.50d {+09d 30' 16"}
  SUN_DIST:        113.58 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
  MOON_POSTN:        3.54d {+00h 14m 10s}   -3.16d {-03d 09' 52"}
  MOON_DIST:        92.73 [deg]
  MOON_ILLUM:      95 [%]
  GAL_COORDS:        3.73, -0.12 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      268.81, -2.36 [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 #23183
  O.J. Roberts (USRA/NASA) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
  "At 18:57:26.58 UT on 28 August 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 180828A (trigger 557175451 / 180828790), which was also detected by Swift (Beardmore et al. 2018, GCN 23182). The GBM on-ground location is consistent with the Swift position.
  The angle from the Fermi LAT boresight at the GBM trigger time using the Swift-XRT position is 77 degrees.
  The GBM light curve consists of multiple bright pulses with a duration (T90) of 8.3 s (50-300 keV). The time-averaged spectrum from T0+1.5s to T0+11 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.46 +/- 0.02 and the cutoff energy, parameterized as Epeak, is 358 +/- 9 keV.
  A Band function fits the interval equally well, with Epeak =346 +/- 12 keV, alpha = -0.44 +/- 0.03 and beta = -3.01 +/- 0.33.
  The event fluence (10-1000 keV) over the T90 interval is (3.39 +/- 0.5)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0 +8s in the 10-1000 keV band is 38 +/- 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 #23184
  P.A. Evans, M.R. Goad and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team:
  Using 973 s of XRT Photon Counting mode data and 1 UVOT images, 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 = 268.71784, -25.79805 which is equivalent to:

  RA (J2000):  17 54 52.28
  Dec (J2000): -25 47 53.0
  

  with an uncertainty of 2.0 arcsec (radius, 90% confidence).
  This position may be improved as more data are received. The latest position can be viewed athttp://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
  Preliminary analysis of the XRT light curve (http://www.swift.ac.uk/xrt_curves/00856977/) suggests that this object is likely a GRB, not a Galactic transient. Analysis is ongoing.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #23185
  S. J. LaPorte (PSU), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU) and A.P. Beardmore report on behalf of the Swift-XRT team:
  We have analysed 6.6 ks of XRT data for GRB 180828A (Beardmore et al. GCN Circ. 23182), from 121 s to 28.1 ks after the BAT trigger. The data comprise 1.8 ks in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. Using 2040 s of PC mode data and 4 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 = 268.71817, -25.79815 which is equivalent to:

  RA (J2000): 17h 54m 52.36s
  Dec(J2000): -25d 47' 53.3"
  

  with an uncertainty of 1.7 arcsec (radius, 90% confidence).
  The light curve can be modelled with a power-law decay with a decay index of alpha=1.22 (+/-0.05).
  A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.1 (+1.3, -1.1). The best-fitting absorption column is 2.5 (+1.3, -1.0) x 10^23 cm^-2, in excess of the Galactic value of 1.4 x 10^22 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 1.2 x 10^-10 (7.0 x 10^-10) erg cm^-2 count^-1.
  A summary of the WT-mode spectrum is thus:

  Total column:	     2.5 (+1.3, -1.0) x 10^23 cm^-2
  Galactic foreground: 1.4 x 10^22 cm^-2
  Excess significance: 4.0 sigma
  Photon index:	     2.1 (+1.3, -1.1)
  

  If the light curve continues to decay with a power-law decay index of 1.22, the count rate at T+24 hours will be 2.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.0 x 10^-13 (1.8 x 10^-12) erg cm^-2 s^-1.
  The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00856977.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #23188
  C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
  Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180828A (trigger #856977) (Beardmore et al., GCN Circ. 23182). The BAT ground-calculated position is RA, Dec = 268.704, -25.791 deg which is

    RA(J2000)  =  17h 54m 49.1s
    Dec(J2000) = -25d 47' 28.3"
  

  with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 19%.
  The mask-weighted light curve shows a few overlapping pulses that starts at ~ T-7 s and ends at ~T+2 s, with some weak tail emission that lasts till ~ T+30 s. T90 (15-350 keV) is 14.0 +- 8.0 sec (estimated error including systematics).
  The time-averaged spectrum from T-7.29 to T+28.71 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.89 +- 0.06. The fluence in the 15-150 keV band is 8.8 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.29 sec in the 15-150 keV band is 17.8 +- 0.9 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
  The BAT temporal and spectral characteristics are consistent with those of a GRB.
  The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/856977/BA/
• GCN Circular #23189
  Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report:
  We observed the field of GRB 180828A (Beardmore, et al., GCN 23182) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2018/08 29.14 to 2018/08 29.28 UTC (8.29 to 11.70 hours after the BAT trigger), obtaining a total of 1.73 hours exposure in the r and i bands and 0.79 hours exposure in the Z, Y, J, and H bands.
  We find one uncatalogued source within the Swift-XRT error circle (Beardmore at at., GCN 23182) at RA, Dec = 17:54:52.5 -25:47:56.3 (J2000, +/-0.5"). This source is outside the enhanced XRT error region (Evans et al., GCN 23184), within which we find no new sources. In comparison with the 2MASS catalog, we obtain the following detection and 3-sigma upper limit:

   J > 21.4
   H = 20.8 +/- 0.3
  

  These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We note that this field has high extinction, with E[B-V]~16.
  We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
• GCN Circular #23190
  S.W.K. Emery (UCL-MSSL) and A. P. Beardmore (U. Leicester) report on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 180828A 124 s after the BAT trigger (Beardmore et al., GCN Circ. 23182). No optical afterglow consistent with the XRT position (LaPorte et al., GCN Circ. 23185) or the position of the source detected outside the enhanced XRT error region by RATIR (Butler et al., GCN Circ. 23189) 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 initial exposures are:

  Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
  
  white              124        23102         1057         >21.8
  v                16882        39624         1367         >20.3
  b                 5752        28839         1439         >21.7
  u                 5547        34577         1709         >21.1
  uvw1              5342        33925         1082         >20.7
  uvm2              5137        40314         1756         >21.0
  uvw2             11215        38709         2087         >21.2
  

  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 23.65 in the direction of the burst (Schlegel et al. 1998).
• GCN Circular #23191
  T. Khanam, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
  Analysis of AstroSat CZTI data showed the detection of a long GRB 180828A, which was also detected by Swift (Beardmore A. P. et al., GCN 23182) and Fermi-GBM (Roberts O. J. et al., GCN 23183).
  The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 18:57:35.500 UT. The measured peak count rate is 947 cts/s above the background in combined data of four quadrants, with a total of 3607 cts. The local mean background count rate was 557 cts/s. Using cumulative rates, we measure a T90 of 8.9 s.
  It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
  CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
• GCN Circular #23193
  A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report:
  The long-duration GRB 180828A (Swift-BAT detection: Beardmore et al., GCN 23182; Markwardt et al., GCN 23188; Fermi-GBM observation: Roberts & Meegan, GCN 23183; AstroSat-CZTI detection: Khanam et al., GCN 23191) triggered Konus-Wind at T0=68250.016 s UT (18:57:30.016).
  The burst light curve shows a multipeaked structure which starts at ~T0-6 s and has a duration of ~14.7 s. The emission is seen up to ~10 MeV.
  As observed by Konus-Wind, the burst had a fluence of 4.41(-0.17,+0.17)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+7.456 s, of 1.57(-0.24,+0.26)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
  The time-averaged spectrum of the burst (measured from T0 to T0+15.104 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.50(-0.12,+0.12) and Ep = 341(-21,+24) keV (chi2 = 72/88 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.7 (chi2 = 70/87 dof).
  The spectrum near the maximum count rate (measured from T0+6.912 to T0+15.104 s) is best fit in the 20 keV - 10 MeV range by the CPL model with alpha = -0.36(-0.23,+0.26) and Ep = 395(-45,+59) keV (chi2 = 61/86 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.5 (chi2 = 61/85 dof).
  The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180828_T68250/
  All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.