Gamma-ray Burst 181231A

(All information courtesy of the instrument teams.)

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Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 31 Dec 18 03:28:08 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      46
TRIGGER_NUM:     567919668
GRB_RA:          256.650d {+17h 06m 36s} (J2000),
                 256.898d {+17h 07m 35s} (current),
                 255.998d {+17h 04m 00s} (1950)
GRB_DEC:          -2.450d {-02d 27' 00"} (J2000),
                  -2.474d {-02d 28' 26"} (current),
                  -2.384d {-02d 23' 02"} (1950)
GRB_ERROR:       29.43 [deg radius, statistical plus systematic]
GRB_INTEN:       72 [cnts/sec]
DATA_SIGNIF:     5.20 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18483 TJD;   365 DOY;   18/12/31
GRB_TIME:        12463.75 SOD {03:27:43.75} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:        55.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.62
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      93%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       0,1,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       280.22d {+18h 40m 52s}  -23.10d {-23d 06' 13"}
SUN_DIST:         30.59 [deg]   Sun_angle= 1.6 [hr] (West of Sun)
MOON_POSTN:      210.81d {+14h 03m 13s}   -6.89d {-06d 53' 09"}
MOON_DIST:        46.13 [deg]
MOON_ILLUM:      32 [%]
GAL_COORDS:       17.99, 21.91 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      255.76, 20.33 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181231144/quicklook/glg_lc_medres34_bn181231144.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 61.22,24.82 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 31 Dec 18 03:28:18 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     567919668
GRB_RA:          256.733d {+17h 06m 56s} (J2000),
                 256.981d {+17h 07m 55s} (current),
                 256.081d {+17h 04m 20s} (1950)
GRB_DEC:          -2.433d {-02d 25' 59"} (J2000),
                  -2.457d {-02d 27' 25"} (current),
                  -2.368d {-02d 22' 03"} (1950)
GRB_ERROR:       20.27 [deg radius, statistical plus systematic]
GRB_INTEN:       99 [cnts/sec]
DATA_SIGNIF:     7.80 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18483 TJD;   365 DOY;   18/12/31
GRB_TIME:        12463.75 SOD {03:27:43.75} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:        55.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.37
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      91%  GRB
2nd_MOST_LIKELY:   4%  Cyg X-1
DETECTORS:       0,1,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       280.22d {+18h 40m 52s}  -23.10d {-23d 06' 13"}
SUN_DIST:         30.54 [deg]   Sun_angle= 1.5 [hr] (West of Sun)
MOON_POSTN:      210.81d {+14h 03m 14s}   -6.89d {-06d 53' 11"}
MOON_DIST:        46.21 [deg]
MOON_ILLUM:      32 [%]
GAL_COORDS:       18.05, 21.85 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      255.84, 20.36 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181231144/quicklook/glg_lc_medres34_bn181231144.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 61.22,24.82 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 31 Dec 18 03:28:22 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     567919668
GRB_RA:          251.530d {+16h 46m 07s} (J2000),
                 251.774d {+16h 47m 06s} (current),
                 250.887d {+16h 43m 33s} (1950)
GRB_DEC:          -0.580d {-00d 34' 47"} (J2000),
                  -0.613d {-00d 36' 47"} (current),
                  -0.490d {-00d 29' 24"} (1950)
GRB_ERROR:       11.92 [deg radius, statistical only]
DATA_SIGNIF:     -214748364.80 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        18483 TJD;   365 DOY;   18/12/31
GRB_TIME:        12463.75 SOD {03:27:43.75} UT
GRB_PHI:         357.00 [deg]
GRB_THETA:        50.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       280.22d {+18h 40m 52s}  -23.10d {-23d 06' 13"}
SUN_DIST:         35.62 [deg]   Sun_angle= 1.9 [hr] (West of Sun)
MOON_POSTN:      210.81d {+14h 03m 14s}   -6.89d {-06d 53' 12"}
MOON_DIST:        41.33 [deg]
MOON_ILLUM:      32 [%]
GAL_COORDS:       16.86, 27.27 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      250.08, 21.59 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181231144/quicklook/glg_lc_medres34_bn181231144.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_567919668.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
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.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 31 Dec 18 03:36:55 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     567919668
GRB_RA:          253.450d {+16h 53m 48s} (J2000),
                 253.706d {+16h 54m 49s} (current),
                 252.777d {+16h 51m 06s} (1950)
GRB_DEC:          -7.070d {-07d 04' 11"} (J2000),
                  -7.100d {-07d 05' 59"} (current),
                  -6.989d {-06d 59' 20"} (1950)
GRB_ERROR:       6.13 [deg radius, statistical only]
GRB_DATE:        18483 TJD;   365 DOY;   18/12/31
GRB_TIME:        12463.75 SOD {03:27:43.75} UT
GRB_PHI:         353.00 [deg]
GRB_THETA:        56.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41531 (Gnd S/W Version number)
SUN_POSTN:       280.22d {+18h 40m 53s}  -23.10d {-23d 06' 11"}
SUN_DIST:         30.09 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      210.88d {+14h 03m 32s}   -6.91d {-06d 54' 50"}
MOON_DIST:        42.49 [deg]
MOON_ILLUM:      32 [%]
GAL_COORDS:       11.94, 22.18 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      252.95, 15.40 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181231144/quicklook/glg_lc_medres34_bn181231144.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn181231144/quicklook/glg_locplot_all_bn181231144.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:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 31 Dec 18 16:39:30 UT
NOTICE_TYPE:     Fermi-LAT Offline Position
TRIGGER_NUM:     567919668 
GRB_RA:          254.590d {+16h 58m 22s} (J2000),
                 254.832d {+16h 59m 20s} (current),
                 253.953d {+16h 55m 49s} (1950)
GRB_DEC:          +0.610d {+00d 36' 36"} (J2000),
                  +0.582d {+00d 34' 55"} (current),
                  +0.685d {+00d 41' 07"} (1950)
GRB_ERROR:       14.39 [arcmin radius, 90% containment, statistical only]
GRB_DATE:        18483 TJD;   365 DOY;   18/12/31
GRB_TIME:        12463.00 SOD {03:27:43.00} UT
TRIGGER_ID:      0x0
MISC:            0x40000000
SUN_POSTN:       280.82d {+18h 43m 17s}  -23.06d {-23d 03' 46"}
SUN_DIST:         34.61 [deg]   Sun_angle= 1.7 [hr] (West of Sun)
MOON_POSTN:      217.65d {+14h 30m 35s}   -9.35d {-09d 20' 45"}  
MOON_DIST:        38.33 [deg] 
MOON_ILLUM:      26 [%] 
GAL_COORDS:       19.74, 25.24 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      253.20, 23.16 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi LAT Offline position.
COMMENTS:        This Notice was ground-generated -- not flight-generated.
COMMENTS:        It is the result of human-in-the-loop processing.
COMMENTS:        This is a human generated position of a LAT ground detection.
COMMENTS:        This source corresponds to GBM trigger.

GCN Circular #23597
F. Dirirsa (U. Johannesburg) and M. Ohno (Hiroshima U.) report on behalf of the Fermi-LAT team:
On December, 31, 2018 Fermi-LAT detected high-energy emission from GRB 181231A, which was also detected by Fermi-GBM (trigger 567919668 / 181231144).
The best LAT on-ground location is found to be
RA, Dec = 254.59, 0.61 (degrees, J2000)
with an error radius of 0.24 deg (90 % containment, statistical error only). This was 51 deg from the LAT boresight at the time of the GBM trigger:
T0 = 03:27:43.8 UT.
The data from the Fermi-LAT show a significant increase in the event rate after the GBM trigger that is spatially correlated with the GBM emission (7.8 degrees from the GBM location) with high significance. The photon flux above 100 MeV in the time interval 0-5000 s after the GBM trigger is 2.4 (+/-1.2)E-6 ph/cm2/s. The estimated photon index above 100 MeV is 2.21 (+/-0.37).
A Swift ToO has been requested for this burst
The Fermi-LAT point of contact for this burst is Feraol F. Dirirsa ( fdirirsa@uj.ac.za).
The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
GCN Circular #23598
P. Veres, R. Hamburg and C. Meegan (all UAH) report on behalf of the Fermi GBM Team:
"At 03:27:43.75 UT on 31 December 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 181231A (trigger 567919668 / 181231144) which was also detected by Fermi/LAT (Dirirsa et al., GCN 23597). The GBM on-ground location is consistent with the LAT position.
The GBM light curve shows multiple peaks with a duration (T90) of about 37 s (50-300 keV). The time-averaged spectrum from T0-7.2 s to T0+30.7 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.63 +/- 0.13 and the cutoff energy, parameterized as Epeak, is 215 +/- 25 keV.
The event fluence (10-1000 keV) in this time interval is (6.23 +/- 0.46)E-6 erg/cm^2. The 1 second peak photon flux measured starting from T0+14.3 s in the 10-1000 keV band is 2.70 +/- 0.27 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #23599
Y.-D. Hu, X.-Y.Li, E. Fernandez-Garcia, A. Ayala, A. J. Castro-Tirado (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga), R. Fernandez-Munoz (IHSM/UMA-CSIC), M.D. Caballero-Garcia and M. Jelinek (ASU-CAS), on behalf of a larger collaboration, report:
The 60cm BOOTES-2/TELMA robotic telescope at IHSM La Mayora (UMA-CSIC) in Algarrobo Costa (Malaga, Spain) followed up GRB 181231A (Veres et al GCNC 23598). Nine images (60s exposure, unfiltered) were obtained with the COLORES imager spectrograph starting at 05:35:26 UT (~26.1 hr after trigger) in order to cover the entire Fermi/LAT error box (Dirirsa et al. GCNC 23597). No new optical sources were detected down to 18 mag.
This message can be quoted.

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Jochen Greiner, last update: 05-Jan-2019 [Disclaimer]