Gamma-ray Burst 181228A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:53:37 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     879909,   Seg_Num: 0
GRB_RA:           49.831d {+03h 19m 19s} (J2000),
                  50.093d {+03h 20m 22s} (current),
                  49.141d {+03h 16m 34s} (1950)
GRB_DEC:         +13.195d {+13d 11' 42"} (J2000),
                 +13.263d {+13d 15' 46"} (current),
                 +13.014d {+13d 00' 51"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5189 [cnts]    Image_Peak=443 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   147     E_range: 25-100 keV
BKG_INTEN:       21663 [cnts]
BKG_TIME:        10385.84 SOD {02:53:05.84} UT
BKG_DUR:         8 [sec]
GRB_DATE:        18480 TJD;   362 DOY;   18/12/28
GRB_TIME:        10397.62 SOD {02:53:17.62} UT
GRB_PHI:         114.59 [deg]
GRB_THETA:        32.85 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     53.74 [sigma]
IMAGE_SIGNIF:    15.47 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +4  +0  +0 +69  +0 
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        134.67 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.05d {+11h 28m 13s}   +7.90d {+07d 54' 08"}
MOON_DIST:       118.60 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.32,-36.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       50.92, -4.96 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 194.20,10.87 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(3.0<100sec) coincident with the FERMI_GBM event (trignum=567658399).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:53:51 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     567658399
GRB_RA:           44.717d {+02h 58m 52s} (J2000),
                  44.975d {+02h 59m 54s} (current),
                  44.039d {+02h 56m 09s} (1950)
GRB_DEC:         +10.967d {+10d 58' 00"} (J2000),
                 +11.042d {+11d 02' 30"} (current),
                 +10.768d {+10d 46' 04"} (1950)
GRB_ERROR:       6.50 [deg radius, statistical plus systematic]
GRB_INTEN:       314 [cnts/sec]
DATA_SIGNIF:     31.10 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18480 TJD;   362 DOY;   18/12/28
GRB_TIME:        10394.96 SOD {02:53:14.96} UT
GRB_PHI:         134.00 [deg]
GRB_THETA:        70.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.34
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,0,0, 1,1,0, 0,0,
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        129.20 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      172.05d {+11h 28m 13s}   +7.90d {+07d 54' 05"}
MOON_DIST:       124.04 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      166.25,-40.95 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       45.48, -5.75 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181228120/quicklook/glg_lc_medres34_bn181228120.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 171.30,12.47 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(3.0<100sec) coincident with the SWIFT_BAT event (trignum=879909).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:53:56 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      69
TRIGGER_NUM:     567658399
GRB_RA:           43.800d {+02h 55m 12s} (J2000),
                  44.065d {+02h 56m 16s} (current),
                  43.102d {+02h 52m 25s} (1950)
GRB_DEC:         +16.733d {+16d 43' 60"} (J2000),
                 +16.809d {+16d 48' 34"} (current),
                 +16.531d {+16d 31' 52"} (1950)
GRB_ERROR:       5.05 [deg radius, statistical plus systematic]
GRB_INTEN:       525 [cnts/sec]
DATA_SIGNIF:     52.20 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18480 TJD;   362 DOY;   18/12/28
GRB_TIME:        10394.96 SOD {02:53:14.96} UT
GRB_PHI:         138.00 [deg]
GRB_THETA:        65.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.96
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   3%  GRO_J0422_32
DETECTORS:       0,0,0, 0,0,0, 0,0,0, 1,1,0, 0,0,
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        130.23 [deg]   Sun_angle= -8.5 [hr] (East of Sun)
MOON_POSTN:      172.06d {+11h 28m 13s}   +7.90d {+07d 54' 04"}
MOON_DIST:       122.95 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      160.91,-36.85 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       46.28,  0.03 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181228120/quicklook/glg_lc_medres34_bn181228120.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 171.30,12.47 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(3.0<100sec) coincident with the SWIFT_BAT event (trignum=879909).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:53:43 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     567658399
GRB_RA:           45.350d {+03h 01m 24s} (J2000),
                  45.600d {+03h 02m 24s} (current),
                  44.693d {+02h 58m 46s} (1950)
GRB_DEC:          +4.800d {+04d 47' 60"} (J2000),
                  +4.874d {+04d 52' 27"} (current),
                  +4.603d {+04d 36' 12"} (1950)
GRB_ERROR:       20.15 [deg radius, statistical plus systematic]
GRB_INTEN:       298 [cnts/sec]
DATA_SIGNIF:     6.80 [sigma]
INTEG_TIME:      0.256 [sec]
GRB_DATE:        18480 TJD;   362 DOY;   18/12/28
GRB_TIME:        10394.96 SOD {02:53:14.96} UT
GRB_PHI:         130.00 [deg]
GRB_THETA:        75.00 [deg]
DATA_TIME_SCALE: 0.2560 [sec]
HARD_RATIO:      1.40
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,0,0, 1,1,0, 0,0,
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        127.32 [deg]   Sun_angle= -8.6 [hr] (East of Sun)
MOON_POSTN:      172.05d {+11h 28m 13s}   +7.90d {+07d 54' 07"}
MOON_DIST:       125.08 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      172.40,-45.23 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       44.31,-11.84 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181228120/quicklook/glg_lc_medres34_bn181228120.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 171.30,12.47 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(3.0<100sec) coincident with the SWIFT_BAT event (trignum=879909).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:53:52 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     567658399
GRB_RA:           51.050d {+03h 24m 12s} (J2000),
                  51.310d {+03h 25m 14s} (current),
                  50.366d {+03h 21m 28s} (1950)
GRB_DEC:         +11.420d {+11d 25' 12"} (J2000),
                 +11.486d {+11d 29' 11"} (current),
                 +11.244d {+11d 14' 37"} (1950)
GRB_ERROR:       3.07 [deg radius, statistical only]
DATA_SIGNIF:     -214748364.80 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        18480 TJD;   362 DOY;   18/12/28
GRB_TIME:        10394.96 SOD {02:53:14.96} UT
GRB_PHI:         139.00 [deg]
GRB_THETA:        74.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        135.15 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      172.05d {+11h 28m 13s}   +7.90d {+07d 54' 05"}
MOON_DIST:       117.96 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      171.90,-36.54 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       51.63, -6.98 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181228120/quicklook/glg_lc_medres34_bn181228120.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_567658399.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
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(3.0<100sec) coincident with the SWIFT_BAT event (trignum=879909).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 28 Dec 18 03:02:33 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     567658399
GRB_RA:           51.750d {+03h 27m 00s} (J2000),
                  52.013d {+03h 28m 03s} (current),
                  51.059d {+03h 24m 14s} (1950)
GRB_DEC:         +13.270d {+13d 16' 12"} (J2000),
                 +13.335d {+13d 20' 07"} (current),
                 +13.096d {+13d 05' 47"} (1950)
GRB_ERROR:       1.17 [deg radius, statistical only]
GRB_DATE:        18480 TJD;   362 DOY;   18/12/28
GRB_TIME:        10394.96 SOD {02:53:14.96} UT
GRB_PHI:         141.00 [deg]
GRB_THETA:        73.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41531 (Gnd S/W Version number)
SUN_POSTN:       276.88d {+18h 27m 30s}  -23.29d {-23d 17' 07"}
SUN_DIST:        136.44 [deg]   Sun_angle= -9.0 [hr] (East of Sun)
MOON_POSTN:      172.14d {+11h 28m 33s}   +7.87d {+07d 52' 20"}
MOON_DIST:       116.88 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      170.96,-34.72 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       52.76, -5.36 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181228120/quicklook/glg_lc_medres34_bn181228120.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181228120/quicklook/glg_locplot_all_bn181228120.png
COMMENTS:        Fermi-GBM Final Position.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.  
COMMENTS:        This notice was generated completely by automated pipeline processing.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(3.0<100sec) coincident with the SWIFT_BAT event (trignum=879909).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:55:16 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     879909,   Seg_Num: 0
GRB_RA:           49.8142d {+03h 19m 15.4s} (J2000),
                  50.0765d {+03h 20m 18.3s} (current),
                  49.1244d {+03h 16m 29.8s} (1950)
GRB_DEC:         +13.2027d {+13d 12' 09.7"} (J2000),
                 +13.2707d {+13d 16' 14.6"} (current),
                 +13.0218d {+13d 01' 18.3"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       24 [cnts]
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10480.14 SOD {02:54:40.14} UT,   82.5 [sec] since BAT Trigger Time
CENTROID_X:      338.25,  raw= 338  [pixels]
CENTROID_Y:      270.65,  raw= 271  [pixels]
ROLL:            250.20 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -65.39
GRB_POS_XRT_Z:   75.08
IMAGE_URL:       sw00879909000msxps_rw.img
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        134.65 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.07d {+11h 28m 16s}   +7.90d {+07d 53' 48"}
MOON_DIST:       118.63 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.03 [deg] galactic lon,lat of the burst
ECL_COORDS:       50.91, -4.95 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:55:19 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     879909,   Seg_Num: 0
GRB_RA:           49.8142d {+03h 19m 15.4s} (J2000),
                  50.0765d {+03h 20m 18.3s} (current),
                  49.1244d {+03h 16m 29.8s} (1950)
GRB_DEC:         +13.2027d {+13d 12' 09.7"} (J2000),
                 +13.2707d {+13d 16' 14.6"} (current),
                 +13.0218d {+13d 01' 18.3"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       24 [cnts]
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10480.14 SOD {02:54:40.14} UT,   82.5 [sec] since BAT Trigger Time
CENTROID_X:      338.25,  raw= 338  [pixels]
CENTROID_Y:      270.65,  raw= 271  [pixels]
ROLL:            250.20 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -65.39
GRB_POS_XRT_Z:   75.08
IMAGE_URL:       sw00879909000msxps_rw.img
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        134.65 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.07d {+11h 28m 16s}   +7.90d {+07d 53' 47"}
MOON_DIST:       118.63 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.03 [deg] galactic lon,lat of the burst
ECL_COORDS:       50.91, -4.95 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:55:04 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     879909,   Seg_Num: 0
GRB_RA:           49.8142d {+03h 19m 15.40s} (J2000),
                  50.0765d {+03h 20m 18.36s} (current),
                  49.1244d {+03h 16m 29.85s} (1950)
GRB_DEC:         +13.2027d {+13d 12' 09.7"} (J2000),
                 +13.2707d {+13d 16' 14.6"} (current),
                 +13.0218d {+13d 01' 18.3"} (1950)
GRB_ERROR:       6.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       5.46e-10 [erg/cm2/sec]
GRB_SIGNIF:      4.89 [sigma]
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10480.14 SOD {02:54:40.14} UT,   82.5 [sec] since BAT Trigger Time
TAM[0-3]:        327.65 237.20 261.66 243.51
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        134.65 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.07d {+11h 28m 16s}   +7.90d {+07d 53' 50"}
MOON_DIST:       118.63 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.03 [deg] galactic lon,lat of the burst
ECL_COORDS:       50.91, -4.95 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.07 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:57:37 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     879909,   Seg_Num: 0
GRB_RA:           49.831d {+03h 19m 19s} (J2000),
                  50.093d {+03h 20m 22s} (current),
                  49.141d {+03h 16m 34s} (1950)
GRB_DEC:         +13.195d {+13d 11' 42"} (J2000),
                 +13.263d {+13d 15' 46"} (current),
                 +13.014d {+13d 00' 51"} (1950)
GRB_DATE:        18480 TJD;   362 DOY;   18/12/28
GRB_TIME:        10397.62 SOD {02:53:17.62} UT
TRIGGER_INDEX:   147
GRB_PHI:         114.59 [deg]
GRB_THETA:        32.85 [deg]
DELTA_TIME:      -56.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     53.74 [sigma]
IMAGE_SIGNIF:    15.47 [sigma]
LC_URL:          sw00879909000msb.lc
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        134.66 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.09d {+11h 28m 22s}   +7.89d {+07d 53' 20"}
MOON_DIST:       118.64 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.32,-36.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       50.92, -4.96 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 194.20,10.87 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:58:10 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.800d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.179d {+13d 10' 43"} (J2000)
POINT_ROLL:      250.203d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10490.85 SOD {02:54:50.85} UT,   93.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.574
N_STARS:         18
X_OFFSET:        396 [pixels]
Y_OFFSET:        736 [pixels]
X_MAX:           1355 [pixels]
Y_MAX:           1695 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00879909000msufc0093.fits
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        134.63 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.09d {+11h 28m 23s}   +7.89d {+07d 53' 13"}
MOON_DIST:       118.68 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.31,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Dec 18 02:58:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.800d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.179d {+13d 10' 43"} (J2000)
POINT_ROLL:      250.203d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10490.85 SOD {02:54:50.85} UT,   93.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.574
N_STARS:         18
X_OFFSET:        396 [pixels]
Y_OFFSET:        736 [pixels]
X_MAX:           1355 [pixels]
Y_MAX:           1695 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00879909000msufc0093.fits
SUN_POSTN:       276.87d {+18h 27m 29s}  -23.29d {-23d 17' 08"}
SUN_DIST:        134.63 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.10d {+11h 28m 23s}   +7.89d {+07d 53' 09"}
MOON_DIST:       118.69 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.31,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [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 28 Dec 18 03:00:06 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.800d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.179d {+13d 10' 43"} (J2000)
ROLL:            250.203d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10490.85 SOD {02:54:50.85} UT,   93.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     567658513
X_OFFSET:        716 [pixels]
Y_OFFSET:        1056 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       876
Y_GRB_POS:       1216
BINNING_INDEX:   1
IM_URL:          sw00879909000msuni0116.fits
SUN_POSTN:       276.87d {+18h 27m 30s}  -23.29d {-23d 17' 08"}
SUN_DIST:        134.63 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.11d {+11h 28m 27s}   +7.88d {+07d 52' 50"}
MOON_DIST:       118.70 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.31,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [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 28 Dec 18 03:04:49 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.799d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.180d {+13d 10' 47"} (J2000)
POINT_ROLL:      250.205d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10702.85 SOD {02:58:22.85} UT,   305.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.848
N_STARS:         9
X_OFFSET:        396 [pixels]
Y_OFFSET:        736 [pixels]
X_MAX:           1355 [pixels]
Y_MAX:           1695 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00879909000msufc0305.fits
SUN_POSTN:       276.88d {+18h 27m 31s}  -23.29d {-23d 17' 07"}
SUN_DIST:        134.62 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.16d {+11h 28m 38s}   +7.86d {+07d 51' 53"}
MOON_DIST:       118.75 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Dec 18 03:05:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.799d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.180d {+13d 10' 47"} (J2000)
POINT_ROLL:      250.205d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10702.85 SOD {02:58:22.85} UT,   305.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.848
N_STARS:         9
X_OFFSET:        396 [pixels]
Y_OFFSET:        736 [pixels]
X_MAX:           1355 [pixels]
Y_MAX:           1695 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00879909000msufc0305.fits
SUN_POSTN:       276.88d {+18h 27m 31s}  -23.29d {-23d 17' 07"}
SUN_DIST:        134.62 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.16d {+11h 28m 38s}   +7.86d {+07d 51' 50"}
MOON_DIST:       118.75 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [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 28 Dec 18 03:00:20 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.800d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.179d {+13d 10' 43"} (J2000)
ROLL:            250.203d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10490.85 SOD {02:54:50.85} UT,   93.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     567658513
X_OFFSET:        716 [pixels]
Y_OFFSET:        1056 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       876
Y_GRB_POS:       1216
BINNING_INDEX:   1
IM_URL:          sw00879909000msuni0116.fits
SUN_POSTN:       276.87d {+18h 27m 30s}  -23.29d {-23d 17' 08"}
SUN_DIST:        134.63 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.12d {+11h 28m 28s}   +7.88d {+07d 52' 47"}
MOON_DIST:       118.70 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.31,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [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 28 Dec 18 03:06:13 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.799d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.180d {+13d 10' 47"} (J2000)
ROLL:            250.205d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10702.85 SOD {02:58:22.85} UT,   305.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     567658725
X_OFFSET:        716 [pixels]
Y_OFFSET:        1056 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       876
Y_GRB_POS:       1216
BINNING_INDEX:   1
IM_URL:          sw00879909000msuni0328.fits
SUN_POSTN:       276.88d {+18h 27m 31s}  -23.29d {-23d 17' 07"}
SUN_DIST:        134.62 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.17d {+11h 28m 41s}   +7.86d {+07d 51' 36"}
MOON_DIST:       118.76 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [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 28 Dec 18 03:06:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.799d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.180d {+13d 10' 47"} (J2000)
ROLL:            250.205d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10702.85 SOD {02:58:22.85} UT,   305.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     567658725
X_OFFSET:        716 [pixels]
Y_OFFSET:        1056 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       876
Y_GRB_POS:       1216
BINNING_INDEX:   1
IM_URL:          sw00879909000msuni0328.fits
SUN_POSTN:       276.88d {+18h 27m 31s}  -23.29d {-23d 17' 07"}
SUN_DIST:        134.62 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.17d {+11h 28m 41s}   +7.86d {+07d 51' 33"}
MOON_DIST:       118.77 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [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 28 Dec 18 03:05:26 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     879909,   Seg_Num: 0
GRB_RA:           49.8113d {+03h 19m 14.71s} (J2000),
                  50.0736d {+03h 20m 17.67s} (current),
                  49.1215d {+03h 16m 29.16s} (1950)
GRB_DEC:         +13.1999d {+13d 11' 59.6"} (J2000),
                 +13.2679d {+13d 16' 04.5"} (current),
                 +13.0190d {+13d 01' 08.2"} (1950)
GRB_ERROR:       2.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  10615.00 SOD {02:56:55.00} UT,   217.4 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       276.88d {+18h 27m 31s}  -23.29d {-23d 17' 07"}
SUN_DIST:        134.64 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.16d {+11h 28m 39s}   +7.86d {+07d 51' 45"}
MOON_DIST:       118.74 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.04 [deg] galactic lon,lat of the burst
ECL_COORDS:       50.90, -4.95 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.11% < P(seren) < 0.58%.

GCN Circular #23570
M. J. Moss (George Washington University), S. D. Barthelmy (GSFC), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 02:53:17 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 181228A (trigger=879909). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 49.831, +13.195, which is
```
   RA(J2000)  =  03h 19m 19s
   Dec(J2000) = +13d 11' 42"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple overlapping peaks with a duration of about 25 sec. The peak count rate was ~7000 counts/sec (15-350 keV), at ~13 sec after the trigger.
The XRT began observing the field at 02:54:40.1 UT, 82.5 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source with an enhanced position: RA, Dec 49.8114, 13.2000 which is equivalent to:
```
   RA(J2000)  = 03h 19m 14.75s
   Dec(J2000) = +13d 12' 00.1"
```
with an uncertainty of 2.6 arcseconds (radius, 90% containment). This location is 71 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. No spectrum from the promptly downlinked event data is yet available to determine the column density.
The initial flux in the 2.5 s image was 5.46e-10 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of nominal 150.000 seconds with the White filter starting 93 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. Data from the 2.7'x2.7' sub-image are not available at this time. 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 0.51.
Burst Advocate for this burst is M. J. Moss (mikejmoss3 AT gmail.com). 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 28 Dec 18 03:12:27 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.799d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.180d {+13d 10' 47"} (J2000)
POINT_ROLL:      250.205d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  11256.51 SOD {03:07:36.51} UT,   858.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.882
N_STARS:         59
X_OFFSET:        156 [pixels]
Y_OFFSET:        496 [pixels]
X_MAX:           1595 [pixels]
Y_MAX:           1935 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00879909000msufc0858.fits
SUN_POSTN:       276.88d {+18h 27m 32s}  -23.29d {-23d 17' 06"}
SUN_DIST:        134.62 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.23d {+11h 28m 55s}   +7.84d {+07d 50' 21"}
MOON_DIST:       118.82 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Dec 18 03:12:44 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.799d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.180d {+13d 10' 47"} (J2000)
POINT_ROLL:      250.205d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  11256.51 SOD {03:07:36.51} UT,   858.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.882
N_STARS:         59
X_OFFSET:        156 [pixels]
Y_OFFSET:        496 [pixels]
X_MAX:           1595 [pixels]
Y_MAX:           1935 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00879909000msufc0858.fits
SUN_POSTN:       276.88d {+18h 27m 32s}  -23.29d {-23d 17' 06"}
SUN_DIST:        134.62 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.23d {+11h 28m 55s}   +7.84d {+07d 50' 17"}
MOON_DIST:       118.83 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [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 28 Dec 18 03:13:50 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.799d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.180d {+13d 10' 47"} (J2000)
ROLL:            250.205d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  11256.51 SOD {03:07:36.51} UT,   858.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     567659278
X_OFFSET:        715 [pixels]
Y_OFFSET:        1055 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       875
Y_GRB_POS:       1215
BINNING_INDEX:   1
IM_URL:          sw00879909000msuni0881.fits
SUN_POSTN:       276.88d {+18h 27m 32s}  -23.29d {-23d 17' 06"}
SUN_DIST:        134.62 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.24d {+11h 28m 58s}   +7.83d {+07d 50' 04"}
MOON_DIST:       118.84 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [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 28 Dec 18 03:14:00 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     879909,   Seg_Num: 0
POINT_RA:         49.799d {+03h 19m 12s} (J2000)
POINT_DEC:       +13.180d {+13d 10' 47"} (J2000)
ROLL:            250.205d
IMG_START_DATE:  18480 TJD;   362 DOY;   18/12/28
IMG_START_TIME:  11256.51 SOD {03:07:36.51} UT,   858.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     567659278
X_OFFSET:        715 [pixels]
Y_OFFSET:        1055 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       875
Y_GRB_POS:       1215
BINNING_INDEX:   1
IM_URL:          sw00879909000msuni0881.fits
SUN_POSTN:       276.88d {+18h 27m 32s}  -23.29d {-23d 17' 06"}
SUN_DIST:        134.62 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:      172.24d {+11h 28m 58s}   +7.83d {+07d 50' 02"}
MOON_DIST:       118.84 [deg]
MOON_ILLUM:      64 [%]
GAL_COORDS:      169.30,-36.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       50.89, -4.97 [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 #23571
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 181228A (Moss et al., GCN 23570) starting at 03:03:30 UT, 613 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 do not detect any optical afterglow candidate within the XRT position error circle (Moss et al., GCN 23570), neither in single image, nor in the co-add images. The typical limiting magnitude of our single clear image is about 18.5 mag calibrated to the Pan-STARRS1 catalog.
GCN Circular #23574
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1212 s of XRT Photon Counting mode data and 2 UVOT images for GRB 181228A, 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 = 49.81214, +13.20208 which is equivalent to:
```
RA (J2000): 03h 19m 14.91s
Dec (J2000): +13d 12' 07.5"
```
with an uncertainty of 1.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #23575
P. D'Avanzo, S.Covino, D. Fugazza, A. Melandri (INAF-OAB), on behalf of the REM team, report:
We observed the field of GRB 181228A (Moss et al. GCN 23570) with the REM 60cm robotic telescope located at the ESO premise of La Silla (Chile). The observations were performed starting on 2018 December 28 at 02:54:10 UT (i.e. 53 seconds after the burst) and were carried in the g, r, i, z, J, H and K bands.
In the first set of NIR images (carried out in the H band) we detect an uncatalogued, fading source at the following position:
```
RA (J2000): 03:19:15.05
Dec (J2000): +13:12:06.7
+/- 0.5". 
```
This position is consistent with the enhanced XRT position reported by Beardmore et al. (GCN 23574). The NIR source we detect is not present in the 2MASS catalogue. We propose this source as the NIR afterglow of GRB 181228A.
From preliminary photometry we estimate the following magnitudes:
```
H = 14.3 +/- 0.1 at t-t0 = 122 s
H = 16.4 +/- 0.3 at t-t0 = 601 s
```
(Vega; calibrated against the 2MASS catalogue). At the same epochs, the source is not detected in the optical down to a 3sigma limiting magnitude of r ~ 18.0 (AB; calibrated against the pan-STARRS catalogue). This is consistent with the early optical non-detection reported by Zheng & Filippenko (GCN 23571).
GCN Circular #23576
V. Lipunov, N.Tiurina, E. Gorbovskoy, V.Kornilov, P.Balanutsa, A.Kuznetsov, D. Vlasenko, D.Kobtsev (Lomonosov Moscow State University, SAI),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar),
H. Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio of San Juan National University, Argentina)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
A. Tlatov, V.Senik, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
O. Gress, N.M. Budnev, S. Yazev, O. Chuvalaev (Irkutsk State University, API)
V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University)
MASTER-OAFA robotic telescope (Global MASTER Net http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the GRB181228A (Moss et al., GCN #23570) 26 sec after notice time and 47 sec after trigger time at 2018-12-28 02:54:05 UT. On our first (10s exposure) set we found 1 optical transient within SWIFT XRT error-box (Beardmore et al., GCN #23574) brighter than 17.5.
```
  T-Tmid      Date      Time     Expt.        Ra                Dec    Mag
    s                   UTC       s 
---------|-------------------|------|-----------------|-----------------|-------
     52   2018-12-28 02:54:05     10  ( 03h 19m 14.80s , +13d 12' 02".80 ) 17.0
```
The 5-sigma upper limit has been about 17.5 mag . Coordinate error ~2".
The galactic latitude b = -35 deg., longitude l = 170 deg. The observations made on zenit distance = 49 deg.The moon (64 % bright part) below the horizon (The altitude of the Moon is -14 deg. ). The sun altitude is -29.6 deg. The object can be observed till 2018-12-28 06:59:09 The message may be cited.
GCN Circular #23578
N.Tyurina, V. Lipunov, E. Gorbovskoy, V.Kornilov, P.Balanutsa, A.Kuznetsov, D. Vlasenko, D.Kobtsev Lomonosov Moscow State University, SAI
R. Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA)
H. Levato Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
D. Buckley, South African Astronomical Observatory
A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, Irkutsk State University
V. Yurkov, A. Gabovich, Yu. Sergienko, Blagoveschensk Educational State University, Blagoveschensk
MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the GRB181228A (Moss et al., GCN #23570) 26 sec after notice time and 47 sec after trigger time at 2018-12-28 02:54:05 UT. On our first (10s exposure) set we found 1 optical transient within SWIFT XRT error-box (Beardmore et al., GCN #23574) brighter than 17.5.
```
  T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
    s                   UTC         s 
---------|---------------------|-------|-----------------|-----------------|-------
     52   2018-12-28 02:54:05       10   ( 03h 19m 14.80s , +13d 12' 02".8 )    17.0
```
The 5-sigma upper limit has been about 17.5 mag . Coordinate error ~1".
The galactic latitude b = -35 deg., longitude l = 170 deg. The observations made on zenit distance = 49 deg.The moon (64 % bright part) below the horizon (The altitude of the Moon is -14 deg. ). The sun altitude is -29.6 deg. The object can be observed till 2018-12-28 06:59:09 The message may be cited.
GCN Circular #23579
E. Bissaldi (Politecnico & INFN Bari) and P. Veres (UAH) report on behalf of the Fermi GBM Team:
"At 02:53:14.96 UT on 28 December 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 181228A (trigger 567658399 / 181228120), which was also detected by the Swift/BAT (Moss et al. 2018, GCN 23570). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 72 degrees.
The GBM light curve consists of a two-peaked emission episode with a duration (T90) of about 18 s (50-300 keV). The time-averaged spectrum from T0 to T0+19 s is best fit by a Band function with Epeak = 182 +/- 8 keV, alpha = -0.82 +/- 0.03, and beta = -2.25 +/- 0.07.
The event fluence (10-1000 keV) in this time interval is (2.56 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+15.6 s in the 10-1000 keV band is 16.0 +/- 0.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #23580
A. Volnova (IKI), I. Reva (FAPHI), A. Pozanenko (IKI), E. Mazaeva (IKI), S. Belkin (IKI), A. Kusakin (FAPHI), M. Krugov (FAPHI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 181228A (Moss et al., GCN 23570; Beardmoreet al., GCN 23574) with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting on Dec. 28 (UT) 13:35:51. We do not detected the OT (D'Avanzo et al., GCN 23574; Lipunov et al. GCN 23576). Preliminary photometry of the field is following.
```
Date       UT start t-T0    Filter Exp.   OT   Err. UL
                     (mid, days) (s)

2018-12-28 13:35:51 0.46359 R      21*120 n/d  n/d  21.7
```
The photometry is based on nearby USNO-B1.0 star
```
USNO-B1.0_id R2
1032-0046066 16.66
```
GCN Circular #23581
GRB 181228A: Swift/UVOT Upper Limits
S. J. LaPorte (PSU) and M. J. Moss (George Washington University) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 181228A 93 s after the BAT trigger (Moss et al., GCN Circ. 23570). No optical afterglow consistent with the XRT position (Moss et al. GCN Circ. 23570) 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            93          243          147         >20.4
u_FC               305          555          246         >20.6
white               93         1354          373         >21.0
v                  634         1404           97         >19.1
b                  561         1330           78         >20.5
u                  305         1305          304         >20.5
w1                 684         1280           39         >18.4
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.51 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #23583
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC), M. J. Moss (GWU), 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-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 181228A (trigger #879909) (Moss et al., GCN Circ. 23570). The BAT ground-calculated position is RA, Dec = 49.831, 13.212 deg which is
```
  RA(J2000)  =  03h 19m 19.5s
  Dec(J2000) = +13d 12' 44.0"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 30%.
The mask-weighted light curve shows a multi-peaked structure. The main structure starts at ~T-4 s and ends at ~T+20 s, with the highest peak occurs at ~ T+13 s. After the main pulse, there is another much weaker pulse that starts at ~ T+200 s and ends at ~T+340 s. T90 (15-350 keV) is 257.3 +- 102.5 sec (estimated error including systematics).
The time-averaged spectrum from T-4.0 to T+337.9 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.45 +- 0.06. The fluence in the 15-150 keV band is 1.0 +- 0.03 x 10^-05 erg/cm2. The 1-sec peak photon flux measured from T+13.08 sec in the 15-150 keV band is 9.5 +- 0.5 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/879909/BA/
GCN Circular #23584
S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and M.J. Moss report on behalf of the Swift-XRT team:
We have analysed 6.2 ks of XRT data for GRB 181228A (Moss et al. GCN Circ. 23570), from 88 s to 58.6 ks after the BAT trigger. The data comprise 405 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 23574).
The late-time light curve (from T0+12.9 ks) can be modelled with a power-law decay with a decay index of alpha=0.95 (+0.29, -0.28).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.60 (+/-0.05). The best-fitting absorption column is 3.30 (+0.28, -0.27) x 10^21 cm^-2, in excess of the Galactic value of 2.9 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.80 (+0.20, -0.19) and a best-fitting absorption column of 5.3 (+1.4, -1.2) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.6 x 10^-11 (6.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     5.3 (+1.4, -1.2) x 10^21 cm^-2
Galactic foreground: 2.9 x 10^21 cm^-2
Excess significance: 3.2 sigma
Photon index:	     1.80 (+0.20, -0.19)
```
If the light curve continues to decay with a power-law decay index of 0.95, the count rate at T+24 hours will be 0.012 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.7 x 10^-13 (8.4 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/00879909.
This circular is an official product of the Swift-XRT team.
GCN Circular #23588
Z.P. Zhu, L.P. Xin, D. Xu, J.B. Zhang (NAOC), X. Zhang, J.H. Liu (XAO) report:
We observed the field of GRB 181228A (Moss et al., GCN 23570) using the 2.16-m telescope located at Xinglong, Hebei, China, equipped with the BFOSC camera. We obtained 6x300s and 2x600s frames in I-band, starting at 13:04:00 UT on 2018-12-28, i.e., 10.18 hrs after the BAT trigger.
The afterglow of GRB 181228A (e.g., Moss et al., GCN 23570; D'Avanzo et al., GCN 23575; Lipunov et al., GCN 23576) is not detected in our stacked image, down to a limiting magnitude of ~20.5 mag, calibrated with the nearby PanSTARRS field.
GCN Circular #23590
M. Oeda, K. L. Murata, R. Itoh, Y. Tachibana, S. Harita, K. Morita, K. Shiraishi, K. Iida, M. Niwano, R. Adachi, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 181228A (M. J. Moss et al., GCN Circular #23570) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 09:04:35.19 UT. We did not find any new point source within the enhanced XRT circle (A.P. Beardmore et al., GCN Circular #23574) in all three bands. We obtained following limits for the magnitudes.
```
T0+[hour]    MID-UT      T-EXP[sec]    g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
6.188       13:04:51          25320      >19.1     >19.0     >18.6
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used UCAC-4 catalog for flux calibration.
GCN Circular #23593
D. Xu (NAOC), D.B. Malesani (DAWN/NBI/DTU and DARK/NBI), J.P.U. Fynbo (DAWN/NBI and DAWN/DTU), M.I. Andersen (NBI), T. Pursimo (NOT) report:
We observed the field of GRB 181228A (Moss et al., GCN 23570) using the 2.56m Nordic Optical Telescope (NOT) equipped with ALFOSC, starting at 23:56:20 UT on 2018-12-28, i.e., 21.05 hr after the BAT trigger. We obtained 3x300s unfiltered frames and 3x300s frames in the Sloan i-band.
There is a weak detection in our stacked image at the REM position (D'Avanzo et al., GCN 23575), thus also being consistent with the enhanced XRT error circle (Beardmore et al., GCN 23574). The above position is not consistent with that of MASTER OT reported in Lipunov et al. (GCN 23576). The NOT source has m(i)~25.0+/-0.5, calibrated with nearby PanSTARRS stars, and thus it could be the optical counterpart of GRB 181228A.
GCN Circular #23594
V. Lipunov, N.Tiurina, E. Gorbovskoy, V.Kornilov, P.Balanutsa, A.Kuznetsov, D. Vlasenko, D.Kobtsev (Lomonosov Moscow State University, SAI),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar),
H. Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio of San Juan National University, Argentina)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
A. Tlatov, V.Senik, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
O. Gress, N.M. Budnev, S. Yazev, O. Chuvalaev (Irkutsk State University, API)
V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University)
The optical source detected by MASTER (Lipunov et al., GCN 23576) insidet Swift BAT GRB 181228A error box (Moss et al., GCN 23570) regardless of the infrared telescope REM (D'Avanzo et al., GCN 23575) is one and the same source. The difference in coordinates is less than 3 sigma. Our coordinates are of course rather rough, since the source itself is very weak. Let me remind you that the pixel MASTER is equal to 2.5 arcsec. OT (not infrared) discovered by MASTER is disappear on late imeges!
HNY!
The message may be cited.
GCN Circular #23596
S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), R. Ya. Inasaridze (AbAO), E. Mazaeva (IKI), A. Volnova (IKI), V. R. Ayvazian (AbAO), G. V. Kapanadze (AbAO) report on behalf of the IKI GRB-FuN:
We observed the field of GRB 181228A (Moss et al., GCN 23570; Beardmore et al., GCN 23574) with AZT-33IK telescope of Sayan observatory (Mondy) starting on Dec. 28 (UT) 13:48:11 in I-filter, and AS-32 telescope of Abastumani Observatory (AbAO) on Dec. 28 (UT) 15:13:46 in R-filter. We do not detected the afterglow (D'Avanzo et al., GCN 23575; Lipunov et al. GCN 23576; Xu et al., GCN 23593).
Preliminary photometry of the field is following.
```
Date       UT start t-T0    Filter Exp.  OT    Err. UL
                    (mid, days) (s)

2018-12-28 13:48:11 0.47494 I      30*120 n/d  n/d   23.8
2018-12-28 15:13:46 0.54879 R      63*60  n/d  n/d   21.0
```
The photometry is based on nearby USNO-B1.0 stars
```
USNO-B1.0_id R2    I2
1032-0046066 16.66 16.08
1031-0043284 16.04 15.36
```
GCN Circular #23669
Martin Jelinek and Jan Strobl (ASU CAS Ondrejov, CZ), Martin Masek, Petr Janecek, Sergey Karpov, Jakub Jurysek, Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza (Institute of Physics, Prague, CZ)
report:
The 25cm robotic telescope FRAM-ORM at La Palma (Spain) reacted robotically to the alert of GRB181228A (Moss et al, GCNC 23570), obtaining a series of 20s R-band images starting at 02:53:51.1UT, i.e. 34s post trigger.
We do not detect any new source in comparison to USNO-B1.0 catalog neither in single images (3-sigma limit R>~17.1) nor in a combined 20x20s frame (mean exp time 269s post trigger, 3-sigma limit R>~18.7).
Martin Jelínek, +420602105255, +34617840945, lascaux.asu.cas.cz/mates Astronomický ústav AVČR, Ondřejov

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