Gamma-ray Burst 191227A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 27 Dec 19 01:39:55 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     946344,   Seg_Num: 0
GRB_RA:          319.170d {+21h 16m 41s} (J2000),
                 319.447d {+21h 17m 47s} (current),
                 318.474d {+21h 13m 54s} (1950)
GRB_DEC:         -16.704d {-16d 42' 15"} (J2000),
                 -16.620d {-16d 37' 11"} (current),
                 -16.914d {-16d 54' 49"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       6770 [cnts]    Image_Peak=379 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   155     E_range: 50-350 keV
BKG_INTEN:       20413 [cnts]
BKG_TIME:        5959.84 SOD {01:39:19.84} UT
BKG_DUR:         8 [sec]
GRB_DATE:        18844 TJD;   361 DOY;   19/12/27
GRB_TIME:        5977.57 SOD {01:39:37.57} UT
GRB_PHI:         -142.05 [deg]
GRB_THETA:        49.80 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     76.49 [sigma]
IMAGE_SIGNIF:    16.65 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +3  +5 -100  +0 -74  +0 
SUN_POSTN:       275.43d {+18h 21m 44s}  -23.34d {-23d 20' 30"}
SUN_DIST:         41.75 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:      286.61d {+19h 06m 26s}  -23.30d {-23d 18' 06"}
MOON_DIST:        31.51 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       33.14,-39.48 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      316.45, -0.84 [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 = 183.85,11.85 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(13.0<100sec) coincident with the FERMI_GBM event (trignum=599103569).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 27 Dec 19 01:39:59 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     599103569
GRB_RA:          326.933d {+21h 47m 44s} (J2000),
                 327.216d {+21h 48m 52s} (current),
                 326.226d {+21h 44m 54s} (1950)
GRB_DEC:         -23.417d {-23d 25' 00"} (J2000),
                 -23.323d {-23d 19' 23"} (current),
                 -23.649d {-23d 38' 56"} (1950)
GRB_ERROR:       25.77 [deg radius, statistical plus systematic]
GRB_INTEN:       193 [cnts/sec]
DATA_SIGNIF:     8.00 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        18844 TJD;   361 DOY;   19/12/27
GRB_TIME:        5964.72 SOD {01:39:24.72} UT
GRB_PHI:          47.00 [deg]
GRB_THETA:       105.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.57
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      93%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
SUN_POSTN:       275.43d {+18h 21m 44s}  -23.34d {-23d 20' 30"}
SUN_DIST:         47.27 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      286.61d {+19h 06m 26s}  -23.30d {-23d 18' 06"}
MOON_DIST:        37.16 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       27.50,-48.53 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      321.24, -9.52 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191227069/quicklook/glg_lc_medres34_bn191227069.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(13.0<100sec) coincident with the SWIFT_BAT event (trignum=946344).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 27 Dec 19 01:39:48 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     599103569
GRB_RA:          340.417d {+22h 41m 40s} (J2000),
                 340.690d {+22h 42m 46s} (current),
                 339.733d {+22h 38m 56s} (1950)
GRB_DEC:         -24.467d {-24d 28' 00"} (J2000),
                 -24.362d {-24d 21' 41"} (current),
                 -24.728d {-24d 43' 41"} (1950)
GRB_ERROR:       26.92 [deg radius, statistical plus systematic]
GRB_INTEN:       105 [cnts/sec]
DATA_SIGNIF:     5.10 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        18844 TJD;   361 DOY;   19/12/27
GRB_TIME:        5964.72 SOD {01:39:24.72} UT
GRB_PHI:          59.00 [deg]
GRB_THETA:       110.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      1.30
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      93%  GRB
2nd_MOST_LIKELY:   4%  Solar Flare
SUN_POSTN:       275.43d {+18h 21m 44s}  -23.34d {-23d 20' 30"}
SUN_DIST:         59.10 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      286.61d {+19h 06m 26s}  -23.30d {-23d 18' 06"}
MOON_DIST:        49.16 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       30.78,-60.75 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      332.59,-14.99 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191227069/quicklook/glg_lc_medres34_bn191227069.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 27 Dec 19 01:40:05 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     599103569
GRB_RA:          328.770d {+21h 55m 05s} (J2000),
                 329.058d {+21h 56m 14s} (current),
                 328.049d {+21h 52m 12s} (1950)
GRB_DEC:         -28.860d {-28d 51' 35"} (J2000),
                 -28.765d {-28d 45' 52"} (current),
                 -29.097d {-29d 05' 49"} (1950)
GRB_ERROR:       19.42 [deg radius, statistical only]
DATA_SIGNIF:     5.90 [sigma]
DATA_INTERVAL:   2.048 [sec]
GRB_DATE:        18844 TJD;   361 DOY;   19/12/27
GRB_TIME:        5964.72 SOD {01:39:24.72} UT
GRB_PHI:          47.00 [deg]
GRB_THETA:       111.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       275.43d {+18h 21m 44s}  -23.34d {-23d 20' 30"}
SUN_DIST:         48.09 [deg]   Sun_angle= -3.6 [hr] (East of Sun)
MOON_POSTN:      286.61d {+19h 06m 27s}  -23.30d {-23d 18' 06"}
MOON_DIST:        38.33 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       19.75,-51.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      320.90,-15.20 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191227069/quicklook/glg_lc_medres34_bn191227069.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_599103569.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(13.0<100sec) coincident with the SWIFT_BAT event (trignum=946344).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 27 Dec 19 01:40:10 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      70
TRIGGER_NUM:     599103569
GRB_RA:          329.800d {+21h 59m 12s} (J2000),
                 330.053d {+22h 00m 13s} (current),
                 329.167d {+21h 56m 40s} (1950)
GRB_DEC:          +3.050d {+03d 02' 60"} (J2000),
                  +3.146d {+03d 08' 47"} (current),
                  +2.810d {+02d 48' 37"} (1950)
GRB_ERROR:       4.08 [deg radius, statistical plus systematic]
GRB_INTEN:       1254 [cnts/sec]
DATA_SIGNIF:     121.90 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18844 TJD;   361 DOY;   19/12/27
GRB_TIME:        5964.72 SOD {01:39:24.72} UT
GRB_PHI:          57.00 [deg]
GRB_THETA:        80.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.70
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
SUN_POSTN:       275.43d {+18h 21m 44s}  -23.34d {-23d 20' 30"}
SUN_DIST:         59.40 [deg]   Sun_angle= -3.6 [hr] (East of Sun)
MOON_POSTN:      286.61d {+19h 06m 27s}  -23.30d {-23d 18' 06"}
MOON_DIST:        49.90 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       62.07,-38.69 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      333.00, 14.40 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191227069/quicklook/glg_lc_medres34_bn191227069.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(13.0<100sec) coincident with the SWIFT_BAT event (trignum=946344).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 27 Dec 19 01:48:51 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     599103569
GRB_RA:          319.700d {+21h 18m 48s} (J2000),
                 319.973d {+21h 19m 53s} (current),
                 319.017d {+21h 16m 04s} (1950)
GRB_DEC:         -13.170d {-13d 10' 11"} (J2000),
                 -13.085d {-13d 05' 05"} (current),
                 -13.381d {-13d 22' 52"} (1950)
GRB_ERROR:       1.00 [deg radius, statistical only]
GRB_DATE:        18844 TJD;   361 DOY;   19/12/27
GRB_TIME:        5964.72 SOD {01:39:24.72} UT
GRB_PHI:          43.00 [deg]
GRB_THETA:        93.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       275.44d {+18h 21m 46s}  -23.34d {-23d 20' 29"}
SUN_DIST:         43.35 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:      286.70d {+19h 06m 47s}  -23.30d {-23d 18' 00"}
MOON_DIST:        33.13 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.59,-38.57 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      318.01,  2.38 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191227069/quicklook/glg_lc_medres34_bn191227069.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191227069/quicklook/glg_locplot_all_bn191227069.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(8.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=8473).

GCN NOTICE

 
TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 27 Dec 19 01:40:48 UT
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    8473,   Sub_Num: 0
GRB_INTEN:      9.43 [sigma]
GRB_TIME:       5972.32 SOD {01:39:32.32} UT
GRB_DATE:       18844 TJD;   361 DOY;   19/12/27
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=2.0000 and Time_Error=1.0000.
COMMENTS:
COMMENTS:       NOTE: This SPIACS event is temporally(8.0<100sec) coincident with the FERMI_GBM event (trignum=599103569).
COMMENTS:
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2019-12/2019-12-27T01-39-32.2549-25168-11152-0.lc

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 27 Dec 19 01:43:48 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     946344,   Seg_Num: 0
GRB_RA:          319.170d {+21h 16m 41s} (J2000),
                 319.447d {+21h 17m 47s} (current),
                 318.474d {+21h 13m 54s} (1950)
GRB_DEC:         -16.704d {-16d 42' 15"} (J2000),
                 -16.620d {-16d 37' 11"} (current),
                 -16.914d {-16d 54' 49"} (1950)
GRB_DATE:        18844 TJD;   361 DOY;   19/12/27
GRB_TIME:        5977.57 SOD {01:39:37.57} UT
TRIGGER_INDEX:   155
GRB_PHI:         -142.05 [deg]
GRB_THETA:        49.80 [deg]
DELTA_TIME:      -11.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     76.49 [sigma]
IMAGE_SIGNIF:    16.65 [sigma]
LC_URL:          sw00946344000msb.lc
SUN_POSTN:       275.44d {+18h 21m 45s}  -23.34d {-23d 20' 30"}
SUN_DIST:         41.75 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:      286.65d {+19h 06m 36s}  -23.30d {-23d 18' 03"}
MOON_DIST:        31.47 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       33.14,-39.48 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      316.45, -0.84 [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 = 183.85,11.85 [deg].

GCN Circular #26593
The Fermi GBM team reports the detection of a likely LONG GRB
At 01:39:24 UT on 27 Dec 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191227A (trigger 599103569.720864 / 191227069).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 319.7, Dec = -13.2 (J2000 degrees, equivalent to J2000 21h 18m, -13d 11'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 93.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191227069/quicklook/glg_skymap_all_bn191227069.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191227069/quicklook/glg_healpix_all_bn191227069.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191227069/quicklook/glg_lc_medres34_bn191227069.gif
GCN Circular #26594
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
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 Swift GRB191227.07 (trigger No 946344,21h 16m 40.68s , -16d 42m 15.8s, R=0.05) errorbox 19 sec after notice time and 51 sec after trigger time at 2019-12-27 01:40:28 UT, with upper limit up to 16.8 mag. The observations began at zenith distance = 83 deg. The sun altitude is -21.4 deg.
The galactic latitude b = -40 deg., longitude l = 34 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1240958
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

      56 |         MASTER-OAFA |   C |    10 | 15.8 |        
      97 |         MASTER-OAFA |   C |    10 | 15.7 |        
     144 |         MASTER-OAFA |   C |    20 | 16.1 |        
     201 |         MASTER-OAFA |   C |    30 | 16.4 |        
     274 |         MASTER-OAFA |   C |    50 | 16.8 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #26595
A. Melandri (INAF-OAB), S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), N. J. Klingler (PSU), S Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC) and M. J. Moss (GWU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 01:39:37 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 191227A (trigger=946344). Swift did not slew immediately due to an observing constraint. The BAT on-board calculated location is RA, Dec 319.170, -16.704 which is
```
   RA(J2000) = 21h 16m 41s
   Dec(J2000) = -16d 42' 15"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 30 sec. The peak count rate was ~12000 counts/sec (15-350 keV), at ~3 sec after the trigger.
Due to a Sun observing constraint, Swift cannot slew to the BAT position until 15:10 UT on 2020 March 23. There will thus be no XRT or UVOT data for this trigger before this time.
Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular #26596
V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, F. Balakin Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
R. Podesta, Carlos Lopez and F. Podesta Observatorio Astronomico Felix Aguilar (OAFA)
D. Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory
K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk Irkutsk State University
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
V. Yurkov, A. Gabovich, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk
Hugo 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
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 GRB191227.07 31 sec after notice time and 51 sec after trigger time at 2019-12-27 01:40:28 UT. On our first (10s exposure) set we found 1 optical transient within Swift error-box (ra=319.167 dec=-16.7033 r=0.05) brighter than 15.3.
```
  T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
       56   2019-12-27 01:40:28      10   (21h 16m 37.28s , -16d 43m 33.5s)     14.4
```
The 5-sigma upper limit has been about 15.3mag The message may be cited.
The OT has irregular early time behaviour since 51.1 till 501.5 seconds after the trigger.
The galactic latitude b = -40 deg., longitude l = 34 deg. The observations made on zenith distance = 83 deg.The moon ( 1 % bright part) below the horizon (The altitude of the Moon is -14 deg. ). The sun altitude is -20.6 deg.
GCN Circular #26597
R. Adachi, K. L. Murata, M. Oeda, K.Shiraishi, K. Iida, M. Niwano, F. Ogawa, R. Hosokawa, S. Toma, N. Nakamura, Y. Yatsu, and N. Kawai (TokyoTech) report on behalf of the MITSuME collaboration:
We observed the field of the optical counterpart (V. Lipunov et al. #26596) of GRB 191227A (The Fermi GBM team #26593, A. Melandri et al. #26595) 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 19/12/27 08:08:42.73 UT. We did not detect the optical counterpart in all three bands. We obtained the following 5-sigma limits for the magnitudes.
```
T0+[hour]    MID-UT T-EXP[sec]   5-sigma limits
-----------------------------------------------------------------------------------------------------
~6.75        08:57:46.67 3360         g’>17.4, Rc>16.9, Ic>16.2
-----------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used UCAC4 catalog for flux calibration. The magnitudes are expressed in the AB system.
GCN Circular #26598
F. Fana Dirirsa (Univ. of Johannesburg), F. Longo (University & INFN, Trieste), M. Axelsson (KTH & Stockholm Univ.), D. Kocevski (NASA/MSFC) and J. Racusin (NASA/GSFC) report on behalf of the Fermi-LAT team:
On December 27, 2019, Fermi-LAT marginally detected high-energy emission from GRB 191227A, which was also detected by Fermi-GBM (GCN 26593) and Swift/BAT (Melandri et al, GCN 26595). The best LAT on-ground location is found to be
RA, Dec 318.0, -16.9 (degrees, J2000)
with an error radius of 0.33 deg (90% containment, statistical error only).
This was 96 deg from the LAT boresight at the time of the GBM trigger and entered in the LAT field of view around 1 ks later. The localisation is consistent with the Swift/BAT position.
The detection significance lies just below the 5-sigma threshold, but more than 3 photons with >90% probability to be associated with the GRB are found in the time interval up to 10ks after the GBM trigger. The photon flux above 100 MeV in this time interval is (9 +/- 4) e-7 ph/cm2/s.
The estimated photon index above 100 MeV is -2.0 +/- 0.3.
Further analysis is ongoing.
The Fermi-LAT point of contact for this burst is Feraol Fana 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 #26599
S.Poolakkil(UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 01:39:24.72 UT on 27 December 2019, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 191227A(trigger 599103569 / 191227069), which was also detected by the Swift/BAT (Melandri et al. 2019, GCN 26595) and Fermi LAT (Fana Dirirsa et al. 2019, GCN 26598). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 96 degrees.
The GBM light curve consists of multiple overlapping pulses with a duration (T90) of about 25 s (50-300 keV). The time-averaged spectrum from T0+8.19 s to T0+37.88 s is best fit by a Band function with Epeak = 362 +/- 10 keV, alpha = -0.93 +/- 0.01 and beta = -2.36 +/- 0.07.
The event fluence (10-1000 keV) in this time interval is (7.30 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+15.8 s in the 10-1000 keV band is 38.0 +/- 0.5 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular #26608
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sakamoto (AGU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 191227A (trigger #946344) (Melandri et al., GCN Circ. 26595). The BAT ground-calculated position is RA, Dec = 319.172, -16.717 deg which is
```
   RA(J2000)  =  21h 16m 41.4s
   Dec(J2000) = -16d 43' 02.5"
```
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 13%.
The mask-weighted light curve shows many overlapping pulses that starts from ~T-30 s and ends at ~T+105 s. Several obvious peaks can be seen at ~T0, ~T+3 s, ~T+5 s, and ~T+11 s, respectively. T90 (15-350 keV) is 58.5 +- 14.4 sec (estimated error including systematics).
The time-averaged spectrum from T-30.55 to T+105.93 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.30 +- 0.05. The fluence in the 15-150 keV band is 2.5 +- 0.1 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+5.28 sec in the 15-150 keV band is 21.8 +- 1.3 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/946344/BA/
GCN Circular #26614
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 191227A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 26593; Swift-BAT detection: Melandri et al., GCN Circ. 26595; Stamatikos et al., GCN Circ. 26608; Fermi-LAT detection: Fana Dirirsa et al., GCN Circ. 26598) triggered Konus-Wind at T0=5970.414 s UT (01:39:30.414).
The burst light curve shows a multi-peaked structure which starts at ~T0-27 s and has a total duration of ~52 s. The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB191227_T05970/
As observed by Konus-Wind, the burst had a fluence of 1.02(-0.08,+0.09)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+8.096 s, of 1.86(-0.35,+0.36)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+29.440 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.70(-0.12,+0.13), the high energy photon index beta = -2.28(-0.16,+0.12), the peak energy Ep = 275(-26,+30) keV (chi2 = 102/97 dof).
The spectrum near the maximum count rate (measured from T0+6.400 to T0+13.056 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.65(-0.18,+0.22), the high energy photon index beta = -2.25(-0.22,+0.15), the peak energy Ep = 266(-40,+46) keV (chi2 = 82/97 dof).
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #26618
Y. F. Du, Y. G. Zheng, C. Cai, Q. Luo, S. Xiao, Q. B. Yi, Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:
At 2019-12-27T01:39:34.400 (T0), Insight-HXMT/HE detected GRB 191227A (trigger ID: HEB191227069) in a routine search of the data, which was also triggered by Fermi/GBM, Swift/BAT and Konus-Wind (GCN #26593).
The Insight-HXMT/HE light curve mainly consists of multiple pulses with a duration (T90) of 20.65 s measured from T0+0.40 s. The 1-ms peak rate, measured from T0+6.72 s, is 18,542 cnts/sec. The total counts from this burst is 118,722 counts. URL_LC: http://www.hxmt.org/images/GRB/HEB191227069_lc.jpg
All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope.
Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org.

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Jochen Greiner, last update: 31-Dec-2019 [Disclaimer]