Gamma-ray Burst 130504B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 May 13 07:32:30 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      46
TRIGGER_NUM:     389345526
GRB_RA:           11.750d {+00h 47m 00s} (J2000),
                  11.926d {+00h 47m 42s} (current),
                  11.092d {+00h 44m 22s} (1950)
GRB_DEC:         +17.783d {+17d 46' 60"} (J2000),
                 +17.856d {+17d 51' 22"} (current),
                 +17.510d {+17d 30' 37"} (1950)
GRB_ERROR:       4.62 [deg radius, statistical plus systematic]
GRB_INTEN:       1638 [cnts/sec]
DATA_SIGNIF:     57.90 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        16416 TJD;   124 DOY;   13/05/04
GRB_TIME:        27123.39 SOD {07:32:03.39} UT
GRB_PHI:         280.00 [deg]
GRB_THETA:        30.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      0.26
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic Transient
DETECTORS:       1,0,0, 1,1,1, 1,1,0, 0,0,0, 0,0,
SUN_POSTN:        41.55d {+02h 46m 11s}  +16.04d {+16d 02' 27"}
SUN_DIST:         28.36 [deg]   Sun_angle= 2.0 [hr] (West of Sun)
MOON_POSTN:      337.05d {+22h 28m 13s}   -4.22d {-04d 12' 54"}
MOON_DIST:        40.86 [deg]
MOON_ILLUM:      30 [%]
GAL_COORDS:      121.44,-45.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       17.80, 11.72 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 62.90,-25.05 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 04 May 13 07:32:44 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     389345526
GRB_RA:          353.450d {+23h 33m 48s} (J2000),
                 353.622d {+23h 34m 29s} (current),
                 352.806d {+23h 31m 13s} (1950)
GRB_DEC:          -5.510d {-05d 30' 35"} (J2000),
                  -5.436d {-05d 26' 09"} (current),
                  -5.786d {-05d 47' 10"} (1950)
GRB_ERROR:       1.00 [deg radius, statistical only]
DATA_SIGNIF:     66.30 [sigma]
DATA_INTERVAL:   0.512 [sec]
GRB_DATE:        16416 TJD;   124 DOY;   13/05/04
GRB_TIME:        27123.39 SOD {07:32:03.39} UT
GRB_PHI:         298.00 [deg]
GRB_THETA:        57.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4143 (Gnd S/W Version number)
SUN_POSTN:        41.55d {+02h 46m 11s}  +16.04d {+16d 02' 27"}
SUN_DIST:         52.05 [deg]   Sun_angle= 3.2 [hr] (West of Sun)
MOON_POSTN:      337.06d {+22h 28m 14s}   -4.21d {-04d 12' 51"}
MOON_DIST:        16.55 [deg]
MOON_ILLUM:      30 [%]
GAL_COORDS:       78.94,-61.56 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      351.81, -2.46 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        Bright hard burst in the GBM.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN Circular #14560
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 07:32:03.39 UT on 04 May 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130504B (trigger 389345526/ 130504314).
The on-ground calculated location, using the GBM trigger data, is RA = 353.5, DEC = -5.6 (J2000 degrees, equivalent to 23 h 34 m, -05 d 34'), with an uncertainty of 1 degree (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 57 degrees. Moreover, this burst was bright enough to result in a Fermi spacecraft autonomous rapid repoint (ARR) maneuver.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of a single spike with a duration (T90) of about 0.4 s (50-300 keV). The time-averaged spectrum from T0-0.064 s to T0+0.448 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.42 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 1300 (+80/-70)keV.
The event fluence (10-1000 keV) in this time interval is (6.01 +/- 0.14)E-06 erg/cm^2. The 0.064-sec peak photon flux measured starting from T0+0.32 s in the 10-1000 keV band is 40 +/- 2 ph/s/cm^2.
A Band function fits the spectrum equally well with Epeak= 1300 +/-80 keV, alpha = -0.42 +/-0.04 and beta = -3.4 (+0.4/-0.9).
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #14561
S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
V. Connaughton, M. Briggs, and C. Meegan, 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, and
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, report:
The short-duration, hard spectrum, intense GRB 130504B (von Kienlin et al., GCN Circ. 14560) has been observed by Fermi GBM, INTEGRAL (SPI-ACS), Konus-Wind, Swift (BAT), and MESSENGER (GRNS), so far, at about 27123 s UT (07:32:03). The burst was outside the coded field of view of the BAT.
We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:
```
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   347.952 (23h 11m 49s)  -5.739 ( -5d 44' 20")
  Corners:
   347.658 (23h 10m 38s)  -5.056 ( -5d 03' 20")
   348.087 (23h 12m 21s)  -6.133 ( -6d 07' 58")
   348.256 (23h 13m 01s)  -6.420 ( -6d 25' 10")
   347.821 (23h 11m 17s)  -5.345 ( -5d 20' 41")
  ---------------------------------------------
```
The error box area is 196 sq. arcmin, and its maximum dimension is 1.5 deg (the minimum one is 2.9 arcmin). The Sun distance was 57 deg.
This box can be improved.
The center of the GBM location (von Kienlin, GCN Circ. 14560) is 5.6 deg from the center of the IPN box.
A triangulation map will be posted at http://www.ioffe.ru/LEA/GRBs/GRB130504_T27119/IPN/
GCN Circular #14565
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report:
The short-duration hard GRB 130504B (Fermi-GBM detection: von Kienlin, GCN 14560; IPN triangulation: Golenetskii et al., GCN 14561) triggered Konus-Wind at T0=3D27119.723s UT (07:31:59.723)
The light curve shows a double-peaked structure from ~T0-0.064 s to ~T0+0.368s. The total duration of the burst is ~0.430 s The emission is seen up to ~8 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130504_T27119/
As observed by Konus-Wind, the burst had a fluence of (9.3 =B1 0.9)x10-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.320s, of (5.0 =B1 0.9)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 15 MeV range by the cutoff power law with the following model parameters: the photon index alpha =3D -0.50 =B1 0.13, the peak energy Ep =3D 980 =B1 125 keV, chi2 =3D 40/36 dof.
All the quoted results are preliminary.
GCN Circular #14600
T. Yasuda, M. Tashiro, Y. Terada, Y. Ishida, H. Ueno, S. Sugimoto (Saitama U.), M. Ohno, K. Takaki, T. Kawano, R. Nakamura, S. Furui, Y. Fukazawa (Hiroshima U.), M. Yamauchi, N. Ohmori, M. Akiyama (Univ. of Miyazaki), K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.), Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA), W. Iwakiri (RIKEN), Y. Hanabata (ICRR), Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo) on behalf of the Suzaku WAM team, report:
The bright, short, IPN localized GRB 130504B (GCN 14560; von Kienlin et al., GCN 14561; Golenetskii et al.) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 07:32:03.063 UT (=T0).
The observed light curve shows a double-peaked structure starting at T0+0.25 s, ending at T0+0.75 s with a duration (T90) of about 0.38 seconds. The fluence in 100 - 1000 keV was 4.97(+0.15/-0.30) x10^-6 erg/cm^2. The 1-s peak flux measured was 7.60 (+0.28/-0.54) photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0 to T0+1 s is well fitted by a power-law with exponential cutoff model:
```
dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha       0.41 (+0.20/-0.22), and
Epeak      1321 (+139/-129) keV (chi^2/d.o.f. = 35.1/24).
```
All the quoted errors are at statistical 90% confidence level.
The light curves for this burst are available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html

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Jochen Greiner, last update: 08-May-2013 [Disclaimer]