Gamma-ray Burst 140620A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN Circular #16444
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and=20 T. Cline on behalf of the Konus-Wind team,
K. Hurley, on behalf of the IPN team,
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.=20 Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein,=20 on behalf of the Fermi GBM team, and
K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM team, report:
The long-duration GRB 140621A has been observed by Konus-Wind, Fermi(GBM=20 trigger 425073013), Swift (BAT), Suzaku (WAM), and INTEGRAL (SPI-ACS),=20 so far, at about 71411 s UT (19:50:11). The burst was outside the coded=20 field of view of the BAT.
We have triangulated it to a Konus-SPI-ACS annulus centered at=20 RA(2000)=3D73.277 deg (04h 53m 07s) Dec(2000)=3D+14.648 deg (+14d 38' 54= "),=20 whose radius is 46.161 =C2=B1 0.185 deg (3 sigma), and to a GBM-SPI-ACS=20 annulus centered at RA(2000)=3D295.874 deg (19h 43m 30s) Dec(2000)=3D+52.= 624=20 deg (+52d 37' 26"), whose radius is 73.043 =C2=B1 1.325 deg (3 sigma). Th= ese=20 annuli intersect to form the error box whose portion with declination=20 lower than about 22.2 degrees is ruled out due to the BAT non-detection=20 in the coded FoV.
The corners of the combined IPN+BAT box are:
```
   ---------------------------------------------
    RA(2000), deg                 Dec(2000), deg
   ---------------------------------------------
   Corners:
     24.883 (01h 39m 32s) +22.492 (+22d 29' 30")
     25.291 (01h 41m 10s) +22.804 (+22d 48' 16")
     25.278 (01h 41m 07s) +22.200 (+22d 12' 00")
     24.879 (01h 39m 31s) +22.200 (+22d 12' 00")
   ---------------------------------------------
```
The error box area is about 720 sq. arcmin, and its maximum dimension is 43 arcmin.
This box may be improved.
A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB140621_T71407/IPN/
A Swift ToO observation has been requested.
The time history and spectrum will be given in a forthcoming GCN Circular.
GCN Circular #16445
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lyssenko, and T. Cline on behalf of the Konus-Wind team, report:
GRB 140621A (IPN triangulation: Golenetskii at al., GCN 16444) triggered Konus-Wind at T0=71407.498 s UT (19:50:07.498).
The burst light curve shows a multipeak structure from ~T0-0.1 s to ~T0+6.2 s; the total duration of the burst is ~6.3 s. The emission is seen up to ~5 MeV.
As observed by Konus-Wind, the burst had a fluence of 7.8(-1.8,+2.9)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0-0.064 s, of 5.6(-1.2,+1.3)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.11 (-0.24,+0.32), and Ep = 740(-260,+640) keV, chi2 = 82/98 dof. Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.0.
The spectrum near the maximum count rate (measured from T0-0.064 to T0+0.064 s) is best fit in the 20 keV - 1.5 MeV range, by a power law with exponential cutoff model with alpha = -0.20(-0.35,+0.55), and Ep = 340(-80,+140) keV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB140621_T71407/
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #16447
G. Younes (USRA/NASA-MSFC) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 19:50:10.89 UT on 21 June 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140621A (trigger 425073013/140621827, IPN triangulation: Golenetskii at al., GCN 16444), which was also detected by Konus-Wind (Golenetskii et al., GCN 16445), and INTEGRAL SPI-ACS.
The angle from the Fermi LAT boresight, using the GBM on-ground calculated location, is 97 degrees.
The GBM light curve consists of two prominent peaks with a duration (T90) of about 6.4 s (50-300 keV). The time-averaged spectrum from T0-0.064 s to T0+6.14 s is adequately fit by a Band function with Epeak = 298 +/- 24 keV, alpha = -0.3 +/- 0.1, and beta = -2.3 +/- 0.2
The event fluence (10-1000 keV) in this time interval is (1.13 +/- 0.03)E-05 erg/cm^2. The 1 second peak photon flux measured starting from T0-0.128 s in the 10-1000 keV band is 8.3 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #16449
V. D'Elia (ASDC), L. Izzo (URoma/ICRA) & J. R. Cummings (NASA/UMBC) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 140621A on 2014-06-23 at 21:01:54 UT, 177 ks after the IPN trigger (Golenetskii et al. GCN Circ 16444, 16445; Younes & Meegan, GCN Circ 16447). An observation centered on RA, Dec: 25.0642, 22.4111 has been secured.
In the 4 ks exposure covering 60% of the IPN box that remained after the BAT non-detection exclusion, we do not find any new X-ray source, down to a three sigma upper limit of 3.05E-03 cts/s.
This circular is an official product of the Swift/XRT team.
GCN Circular #16519
T. Nagayoshi, M. Tashiro, Y. Terada, T. Yasuda, S. Koyama, S. Takeda, J. Enomoto, S. Nakaya, T. Fujinuma, S. Matsuoka (Saitama U.), M. Yamauchi, N. Ohmori, R. Kinoshita (Univ. of Miyazaki), W. Iwakiri (RIKEN), K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.), Y. Hanabata (ICRR), M. Ohno, K. Takaki, T. Kawano, R. Nakamura, S. Furui, Y. Fukazawa (Hiroshima U.), Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA), Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo) on behalf of the Suzaku WAM team, report:
The long-duration GRB 140621A (IPN localization: S. Golenetskii et al., GCN 16444; Konus-Wind observation: S. Golenetskii et al., GCN 16445; Fermi-GBM detection: G. Younes et al., GCN 16447; Swift-XRT observation: V. D'Elia et al., GCN 16449) triggered theSuzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 19:50:10.596 UT (=T0).
The observed light curve shows a multi-peaked structure lasting from T0 to T0+7 s with a duration(T90) of about 6.135 seconds. The fluence in 100 - 1000 keV was 4.96 (+0.11, -0.33) x10^-6 erg/cm^2. The 1-s peak flux measured from T0 was 3.74 (+0.15, -0.30) photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0 to T0+7 s is well fitted by a power-law with exponential cutoff model: dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha 0.87 (+0.30, -0.25), and Epeak 689 (+127, -93) keV (chi^2/d.o.f. = 28.3/29).
All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included.
The light curves for this burst will be 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: 04-Jul-2014 [Disclaimer]