//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8646 SUBJECT: IPN triangulation of short hard GRB 081209 DATE: 08/12/10 16:36:58 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and K. Hurley on behalf of the Konus-Wind team, J. Cummings, S. Barthelmy, N. Gehrels, and H. Krimm, on behalf of the Swift-BAT team, M. Marisaldi, F. Fuschino, E. Del Monte, Y. Evangelista, I. Lapshov, M. Rapisarda, and A. Giuliani, on behalf of the AGILE Team, report: AGILE-MCAL, Swift-BAT, and Konus-Wind observed the short-duration hard spectrum GRB 081209 at about 23:31:56 UT (corresponds to the Fermi/GBM trigger 250558317). The burst was outside the coded field of view of the BAT and SuperAGILE. The burst light curve shows a single peak with a duration of ~0.2 sec. Triangulation gives an annulus centered at RA(2000)=77.269 (05h 09m 05s) Dec(2000)=+17.346 (+17d 20' 47"), whose radius is 48.435 +/- 0.181 deg (3sigma). This intersects the GBM error circle (the Fermi-GBM ground position is RA(2000), Dec(2000) = 88.980d (+05h 55m 55s), +71.450d (+71d 27' 00")) assuming its 3sigma uncertainty of 11.8 deg (7.8deg stat + 3deg syst)) to form a long 3sigma error box whose corners are at ------------------------------------------------- RA(2000) Dec(2000) ------------------------------------------------- 104.995 (06h 59m 59s) +61.438 (+61d 26' 16") 105.760 (07h 03m 02s) +61.616 (+61d 36' 58") 62.128 (04h 08m 31s) +64.879 (+64d 52' 43") 62.813 (04h 11m 15s) +64.597 (+64d 35' 47") -------------------------------------------------- This error box may be improved. Preliminary analysis of the Konus-Wind data yields a burst fluence of ~2x10^-6 erg/cm2 (in the 20 keV - 3 MeV range), and an Epeak of the time-integrated spectrum of ~1 MeV. Detailed spectral parameters will be reported later. The K-W light curve of this GRB and IPN triangulation map is available at http://www.ioffe.ru/LEA/GRBs/GRB081209_T84720/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8647 SUBJECT: Konus-Wind observation of GRB 081209 DATE: 08/12/10 17:49:19 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The short hard GRB 081209 (Golenetskii et al., GCN 8646; Fermi GBM trigger 250558317) triggered Konus-Wind at T0=84720.033 s UT (23:32:00.033). As observed by Konus-Wind the burst had a fluence of 2.39(-0.52, +0.58)x10^-6 erg/cm2, and a 16-ms peak flux measured from T0-0.012 s of 2.68(-0.83, +0.87)x10^-5 erg/cm2/s (both in the 20 keV - 3 MeV energy range). The spectrum accumulated from T0 to T0+0.128 s is well fitted (in the 20 keV - 3 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.33(-0.31, +0.41), and Ep = 961(-257, +432) keV (chi2 = 11.2/17 dof). Fitting by GRB (Band) model yields the same alpha and Ep, and only an upper limit on the high energy photon index: beta < -1.7 (chi2 = 11.2/16 dof). All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8664 SUBJECT: GRB 081209: Fermi GBM detection DATE: 08/12/12 21:24:02 GMT FROM: Colleen A. Wilson at NASA/MSFC/NSSTC Colleen A. Wilson-Hodge (NASA/MSFC) and Valerie Connaughton (UAH) report on behalf of the Fermi GBM Team: "At 23:41:56.39 UT on 9 December 2008, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 081209 (trigger 250558317 / 081209981). The on-ground calculated location, using the GBM trigger data, is RA = 45.3, DEC = 63.5 (J2000 degrees, equivalent to 02 h 20 m, 68 d 52'), with an uncertainty of 4.9 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location overlaps the IPN arc reported in Golenetskii et al. 2008 (GCN Circular #8646). The angle from the Fermi LAT boresight is 109 degrees. The GBM light curve consists of a single peak with a duration (T90) of about 0.4 s (8-1000 keV). The time-averaged spectrum from T0-0.110 s to T0+0.210 s is best fit by a Band function with Epeak = 808 +/- 163 keV, alpha = -0.5 +/- 0.1, and beta = -2.0 +/- 0.1. (chi squared 321.85 for 360 d.o.f.). The event fluence (8-1000 keV) in this time interval is (5.9 +/- 0.3)E-07 erg/cm^2. The 1-sec photon flux measured starting from T0-0.110 s in the 8-1000 keV band is 7.8 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."