Gamma-ray Burst 201128B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 28 Nov 20 17:54:37 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     628278856
GRB_RA:          325.633d {+21h 42m 32s} (J2000),
                 326.009d {+21h 44m 02s} (current),
                 324.729d {+21h 38m 55s} (1950)
GRB_DEC:         -58.783d {-58d 46' 59"} (J2000),
                 -58.687d {-58d 41' 12"} (current),
                 -59.012d {-59d 00' 42"} (1950)
GRB_ERROR:       18.90 [deg radius, statistical plus systematic]
GRB_INTEN:       63 [cnts/sec]
DATA_SIGNIF:     5.60 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        19181 TJD;   333 DOY;   20/11/28
GRB_TIME:        64451.61 SOD {17:54:11.61} UT
GRB_PHI:         267.00 [deg]
GRB_THETA:        55.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.74
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   2%  Generic Transient
DETECTORS:       0,0,0, 1,0,0, 0,1,0, 0,0,0, 0,0,
SUN_POSTN:       245.14d {+16h 20m 34s}  -21.47d {-21d 28' 13"}
SUN_DIST:         67.08 [deg]   Sun_angle= -5.4 [hr] (East of Sun)
MOON_POSTN:       47.28d {+03h 09m 08s}  +14.78d {+14d 46' 58"}
MOON_DIST:        98.15 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:      335.28,-44.68 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      305.10,-41.93 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201128746/quicklook/glg_lc_medres34_bn201128746.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 273.52,-4.22 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 28 Nov 20 17:54:54 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     628278856
GRB_RA:          331.520d {+22h 06m 05s} (J2000),
                 331.857d {+22h 07m 26s} (current),
                 330.711d {+22h 02m 51s} (1950)
GRB_DEC:         -51.330d {-51d 19' 47"} (J2000),
                 -51.228d {-51d 13' 38"} (current),
                 -51.574d {-51d 34' 25"} (1950)
GRB_ERROR:       8.51 [deg radius, statistical only]
DATA_SIGNIF:     5.90 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        19181 TJD;   333 DOY;   20/11/28
GRB_TIME:        64451.61 SOD {17:54:11.61} UT
GRB_PHI:         269.00 [deg]
GRB_THETA:        63.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       245.14d {+16h 20m 34s}  -21.47d {-21d 28' 13"}
SUN_DIST:         71.41 [deg]   Sun_angle= -5.8 [hr] (East of Sun)
MOON_POSTN:       47.29d {+03h 09m 09s}  +14.78d {+14d 47' 01"}
MOON_DIST:        92.67 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:      343.57,-50.67 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      313.25,-36.71 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201128746/quicklook/glg_lc_medres34_bn201128746.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_628278856.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.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 28 Nov 20 18:27:34 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     628278856
GRB_RA:          337.640d {+22h 30m 34s} (J2000),
                 337.976d {+22h 31m 54s} (current),
                 336.831d {+22h 27m 20s} (1950)
GRB_DEC:         -57.230d {-57d 13' 47"} (J2000),
                 -57.122d {-57d 07' 19"} (current),
                 -57.487d {-57d 29' 11"} (1950)
GRB_ERROR:       10.10 [deg radius, statistical only]
GRB_DATE:        19181 TJD;   333 DOY;   20/11/28
GRB_TIME:        64451.61 SOD {17:54:11.61} UT
GRB_PHI:         262.00 [deg]
GRB_THETA:        60.00 [deg]
E_RANGE:         50.000 - 300.000 [keV]
LOC_ALGORITHM:   415 (Gnd S/W Version number)
SUN_POSTN:       245.17d {+16h 20m 40s}  -21.47d {-21d 28' 27"}
SUN_DIST:         73.58 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       47.55d {+03h 10m 12s}  +14.88d {+14d 52' 36"}
MOON_DIST:        91.86 [deg]
MOON_ILLUM:      98 [%]
GAL_COORDS:      332.66,-50.98 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      313.72,-43.60 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201128746/quicklook/glg_lc_medres34_bn201128746.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201128746/quicklook/glg_locplot_all_bn201128746.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 has human-in-the-loop processing.

GCN Circular #28971
James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Jamie Kennea (PSU) report:
Swift/BAT did not trigger on GRB 201128B (T0: 2020-11-28 17:54:11 UTC, Fermi/GBM TRIGGER 628278856).
The Fermi/GBM notice, distributed in near real-time triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
The burst is detected in BAT with a duration of ~15 seconds. This was a weak and slow burst that occurred during a rapid part of a Swift slew. The position of the burst was found with a novel and uncalibrated slew image mosaicing procedure, and so the positional uncertainty is not yet well characterized.
The BAT position is RA, Dec = 339.354, -49.246 deg which is
```
   RA(J2000)  = 22h 37m 24.96s
   Dec(J2000) =  -49d 14’ 45.6”
```
with an estimated uncertainty of at least 5 arcmin.
This position is consistent with the Fermi GBM localization (https://gcn.gsfc.nasa.gov/other/628278856.fermi).
XRT and UVOT follow-up has been requested. Results of follow-up observations will be reported in future circulars.
GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
GCN Circular #28974
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Swift/BAT GRB 201128B. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021044
Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Swift/BAT event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.

GCN Circular #28980
M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the Swift/BAT-detected burst GRB 201128B (James DeLaunay et al. GCN Circ. 28971), collecting 5.0 ks of Photon Counting (PC) mode data between T0+246.0 ks and T0+303.8 ks.
Ten uncatalogued X-ray sources have been detected, however none of them is above the RASS limit or shows definitive signs of fading. Therefore, at the present time we cannot identify which, if any, is the afterglow. Details of these sources are given below:
Source 1:

  RA (J2000.0):  339.4164  =  22:37:39.94
  Dec (J2000.0): -49.2698  =  -49:16:11.1
  Error: 5.1 arcsec (radius, 90% conf.)
  Count-rate: (3.32 [+1.13, -0.93])e-3 ct s^-1	 
  Distance: 169 arcsec from Swift/BAT position.
  Flux: (1.67 [+0.57, -0.47])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:

  RA (J2000.0):  339.0250  =  22:36:5.99
  Dec (J2000.0): -49.1319  =  -49:07:54.7
  Error: 5.2 arcsec (radius, 90% conf.)
  Count-rate: (4.7 [+2.8, -2.0])e-3 ct s^-1   
  Distance: 876 arcsec from Swift/BAT position.

Source 4:

  RA (J2000.0):  339.5648  =  22:38:15.55
  Dec (J2000.0): -49.2141  =  -49:12:50.9
  Error: 7.7 arcsec (radius, 90% conf.)
  Count-rate: (2.35 [+1.05, -0.81])e-3 ct s^-1	 
  Distance: 508 arcsec from Swift/BAT position.
  Flux: (7.8 [+3.5, -2.7])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 5:

  RA (J2000.0):  339.4267  =  22:37:42.42
  Dec (J2000.0): -49.1173  =  -49:07:02.2
  Error: 5.3 arcsec (radius, 90% conf.)
  Count-rate: (1.36 [+0.77, -0.57])e-3 ct s^-1	 
  Distance: 494 arcsec from Swift/BAT position.
  Flux: (9.5 [+5.4, -4.0])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 6:

  RA (J2000.0):  339.2905  =  22:37:9.71
  Dec (J2000.0): -49.3858  =  -49:23:08.7
  Error: 5.1 arcsec (radius, 90% conf.)
  Count-rate: (6.6 [+2.0, -1.6])e-3 ct s^-1   
  Distance: 524 arcsec from Swift/BAT position.
  Flux: (1.69 [+0.50, -0.42])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 7:

  RA (J2000.0):  339.2768  =  22:37:6.43
  Dec (J2000.0): -49.1392  =  -49:08:21.0
  Error: 4.9 arcsec (radius, 90% conf.)
  Count-rate: (4.7 +/- 1.3)e-3 ct s^-1	 
  Distance: 425 arcsec from Swift/BAT position.
  Flux: (2.03 +/- 0.55)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 8:

  RA (J2000.0):  339.2888  =  22:37:9.31
  Dec (J2000.0): -49.1961  =  -49:11:45.9
  Error: 7.2 arcsec (radius, 90% conf.)
  Count-rate: (2.17 [+0.97, -0.77])e-3 ct s^-1	 
  Distance: 236 arcsec from Swift/BAT position.
  Flux: (1.84 [+0.83, -0.65])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 9:

  RA (J2000.0):  339.2747  =  22:37:5.92
  Dec (J2000.0): -49.1221  =  -49:07:19.5
  Error: 9.8 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (3.04 [+1.19, -0.95])e-3 ct s^-1	 
  Distance: 483 arcsec from Swift/BAT position.
  Flux: (7.4 [+2.9, -2.3])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 10:

  RA (J2000.0):  339.5188  =  22:38:4.51
  Dec (J2000.0): -49.1801  =  -49:10:48.4
  Error: 6.9 arcsec (radius, 90% conf.)
  Count-rate: (1.89 [+0.94, -0.72])e-3 ct s^-1	 
  Distance: 454 arcsec from Swift/BAT position.
  Flux: (3.0 [+1.5, -1.1])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 11:

  RA (J2000.0):  339.5043  =  22:38:1.04
  Dec (J2000.0): -49.3084  =  -49:18:30.2
  Error: 5.2 arcsec (radius, 90% conf.)
  Count-rate: (2.14 [+1.07, -0.81])e-3 ct s^-1	 
  Distance: 418 arcsec from Swift/BAT position.
  Flux: (1.04 [+0.52, -0.39])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

A catalogued source was also detected.
The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021044.
This circular is an official product of the Swift-XRT team.

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Jochen Greiner, last update: 13-Dec-2020 [Disclaimer]