Gamma-ray Burst 131028A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 28 Oct 13 01:49:27 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      50
TRIGGER_NUM:     404617745
GRB_RA:           53.883d {+03h 35m 32s} (J2000),
                  54.236d {+03h 36m 57s} (current),
                  52.618d {+03h 30m 28s} (1950)
GRB_DEC:         +70.433d {+70d 25' 60"} (J2000),
                 +70.478d {+70d 28' 42"} (current),
                 +70.267d {+70d 16' 00"} (1950)
GRB_ERROR:       14.38 [deg radius, statistical plus systematic]
GRB_INTEN:       235 [cnts/sec]
DATA_SIGNIF:     8.60 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        16593 TJD;   301 DOY;   13/10/28
GRB_TIME:        6542.35 SOD {01:49:02.35} UT
GRB_PHI:          37.00 [deg]
GRB_THETA:       125.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      1.02
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,1, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       212.53d {+14h 10m 07s}  -13.12d {-13d 07' 17"}
SUN_DIST:        121.09 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:      137.60d {+09h 10m 25s}  +10.81d {+10d 48' 53"}
MOON_DIST:        77.60 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      135.91, 11.82 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       72.42, 49.19 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 149.32,-3.77 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 28 Oct 13 01:49:36 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      61
TRIGGER_NUM:     404617745
GRB_RA:           74.417d {+04h 57m 40s} (J2000),
                  74.742d {+04h 58m 58s} (current),
                  73.245d {+04h 52m 59s} (1950)
GRB_DEC:         +63.333d {+63d 19' 60"} (J2000),
                 +63.354d {+63d 21' 14"} (current),
                 +63.256d {+63d 15' 21"} (1950)
GRB_ERROR:       3.63 [deg radius, statistical plus systematic]
GRB_INTEN:       2718 [cnts/sec]
DATA_SIGNIF:     134.50 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        16593 TJD;   301 DOY;   13/10/28
GRB_TIME:        6542.35 SOD {01:49:02.35} UT
GRB_PHI:          50.00 [deg]
GRB_THETA:       125.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.00
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:     100%  Below horizon
2nd_MOST_LIKELY:   0%  n/a
DETECTORS:       0,0,1, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       212.53d {+14h 10m 07s}  -13.12d {-13d 07' 17"}
SUN_DIST:        121.76 [deg]   Sun_angle= 9.2 [hr] (West of Sun)
MOON_POSTN:      137.60d {+09h 10m 25s}  +10.81d {+10d 48' 52"}
MOON_DIST:        68.37 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      146.78, 12.55 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       80.89, 40.39 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 149.32,-3.77 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 28 Oct 13 01:49:42 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      72
TRIGGER_NUM:     404617745
GRB_RA:           74.417d {+04h 57m 40s} (J2000),
                  74.742d {+04h 58m 58s} (current),
                  73.245d {+04h 52m 59s} (1950)
GRB_DEC:         +63.333d {+63d 19' 60"} (J2000),
                 +63.354d {+63d 21' 14"} (current),
                 +63.256d {+63d 15' 21"} (1950)
GRB_ERROR:       3.52 [deg radius, statistical plus systematic]
GRB_INTEN:       3700 [cnts/sec]
DATA_SIGNIF:     256.30 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        16593 TJD;   301 DOY;   13/10/28
GRB_TIME:        6542.35 SOD {01:49:02.35} UT
GRB_PHI:          50.00 [deg]
GRB_THETA:       125.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.00
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:     100%  Below horizon
2nd_MOST_LIKELY:   0%  n/a
DETECTORS:       0,0,1, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       212.53d {+14h 10m 07s}  -13.12d {-13d 07' 17"}
SUN_DIST:        121.76 [deg]   Sun_angle= 9.2 [hr] (West of Sun)
MOON_POSTN:      137.60d {+09h 10m 25s}  +10.81d {+10d 48' 51"}
MOON_DIST:        68.37 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      146.78, 12.55 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       80.89, 40.39 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 149.32,-3.77 [deg].

GCN Circular #15396
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 01:49:02.35 UT on 28 October 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 131028A (trigger 404617745 / 131028076).
The on-ground calculated location, using the GBM trigger data, is RA = 57.0, DEC = +72.2 (J2000 degrees, equivalent to 03 h 48 m, 72 d 12 '), with an uncertainty of 1.2 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 123 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of a single pulse with a duration (T90) of about 17 s (50-300 keV). The time-averaged spectrum from T0-1.28 s to T0+22.27 s is best fit by a Band function with Epeak = 888 +/-18 keV, alpha = -0.71 +/- 0.01, and beta = -3.4 +/-0.2.
The event fluence (10-1000 keV) in this time interval is (1.62 +/- 0.02)E-04 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+8.13 s in the 10-1000 keV band is 62 +/- 1 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #15397
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
V. Connaughton, M. S. Briggs, C. Meegan, and V. Pelassa, on behalf of the Fermi GBM team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, and
G. Di Cocco, F. Fuschino, M. Galli, C. Labanti, and M. Marisaldi, on behalf of the AGILE MCAL team, report:
The long, bright GRB 131028A was observed by Konus-Wind, Fermi (GCN 15396), INTEGRAL (SPI-ACS), Swift (BAT), AGILE (MCAL), and MESSENGER (GRNS) at about 6542 s UT (01:49:02). The burst was outside the coded field of view of the BAT.
We have triangulated it to a 3 sigma error box whose coordinates are:
```
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    61.225 (04h 04m 54s) +71.595 (+71d 35' 41")
  Corners:
    69.087 (04h 36m 21s) +70.098 (+70d 05' 51")
    66.215 (04h 24m 52s) +70.982 (+70d 58' 56")
    52.752 (03h 31m 00s) +72.570 (+72d 34' 14")
    56.127 (03h 44m 30s) +72.015 (+72d 00' 52")
  ---------------------------------------------
```
The error box area is 1.3 sq. deg, and its maximum dimension is 5.8 deg (the minimum one is 1.2 deg).
A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB131028_T06546/IPN/
Some improvement in this triangulation is possible.
GCN Circular #15398
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report:
The bright, long-duration, hard-spectrum GRB 131028A (Fermi GBM detection: von Kienlin, GCN 15396; IPN triangulation: Hurley at al., GCN 15397) triggered Konus-Wind at T0=3D6546.966 s UT (01:49:06.966).
The burst light curve shows a bright, hard pulse from ~T0 to ~T0+20 s, followed by a tail of softer emission in next ~50 s. The emission in the main pulse is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB131028_T06546/
As observed by Konus-Wind, the burst had a fluence of (2.41 =B1 0.05)x10-4 erg/cm2, and a 64-ms peak flux, measured from T0+5.760 s, of (6.6 =B1 0.3)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+20.736 s) is best fit in the 50 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha =3D -0.82 =B1 0.02, the high energy photon index beta =3D -3.07 =B1 0.17, the peak energy Ep =3D 901 =B1 25 keV, chi2 =3D 97.2/93 dof.
The spectrum near the maximum count rate (measured from T0+5.376 s to T0+6.400 s) is best fit in the 50 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha =3D -0.56 =B1 0.06, the high energy photon index beta =3D -3.18 =B1 0.42, the peak energy Ep =3D 1277 =B1 91 keV, chi2 =3D 119/86 dof.
All the quoted values are preliminary.

Back to JG's homepage

Jochen Greiner, last update: 29-Oct-2013 [Disclaimer]