//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6767 SUBJECT: GRB 070824 - Combined SuperAGILE/IPN Localization DATE: 07/08/30 17:46:04 GMT FROM: Marco Feroci at IASF/INAF Combined SuperAGILE/IPN Localization of the long and bright GRB 070824 I. Donnarumma, E. Del Monte, F. Lazzarotto, M. Feroci, A. Giuliani, M. Marisaldi, on behalf of the AGILE Team, B. Preger, on behalf of the AGILE Science Data Center, S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov and T. Cline on behalf of the Konus-Wind and Konus-A teams, K. Hurley on behalf of the IPN Teams, J. Cummings, D. Palmer and H. Krimm, on behalf of the Swift/BAT team, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, report: GRB 070824 triggered the SuperAGILE ground software trigger on 24 August 2007, at 20:50:09 UT. The GRB was seen as a 3 s long event, preceded by a weaker 2 s precursor 5 s earlier. The SuperAGILE T90 for this event was 9.5 s. The event was observed by SuperAGILE at 48.1 deg off-axis, which is in a region of the instrument field of view with only one-dimensional imaging. In spite of this, the event was observed on all SuperAGILE detectors; due to its hardness, it passed through the collimator shields. In addition, its arrival direction was partially obscured by the Earth's atmosphere for AGILE. For these reasons, the event was imaged by SuperAGILE with only 4.6 sigma significance. The SuperAGILE-only error box is thus a long, narrow strip, limited by the instrument field of view and Earth occultation in one direction and by the imaging uncertainty in the other. For the latter we assumed a 20 arcmin error radius, including statistics and systematics, due to the low statistics of the detection and the far off-axis position. The resulting error box is: RA Dec =============== 172.281 -27.240 171.938 -26.648 147.942 -34.944 148.056 -34.281 The SuperAGILE light curve may be found at the AGILE Science Data Center and AGILE-Team web pages. This event was independently detected by other IPN experiments, namely Konus-Wind, Swift/BAT, RHESSI, AGILE/Minicalorimeter, and the AGILE/Anticoincidence, as well as by Konus-A (Cosmos-2421). Their detection combined to provide further constraints to the burst localization, as shown in the figure at www.ssl.berkeley.edu/ipn3/070824. The final localization of GRB 070824 is thus limited by the corners of a triangular area: RA Dec ================== 1: 172.055 -26.864 2: 171.188 -27.715 3: 172.281 -27.240 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6768 SUBJECT: Konus-Wind observation of GRB 070824 DATE: 07/08/31 12:05:53 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team: The bright long GRB 070824 localized by SuperAGILE/IPN (Donnarumma et al., GCN 6767) triggered Konus-Wind at T0=74999.585 s UT (20:49:59.585). The Konus-Wind light curve shows two pulses with a total duration of ~12 s. As observed by Konus-Wind the burst had a fluence of 2.84(-0.26, +0.09)x10^-5 erg/cm2, and a 16-ms peak flux measured from T0+8.368 s of 2.85(-0.38, +0.29)x10^-5 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 s to T0+16.986 s) is well fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model: dN/dE ~ E^(-alpha)*exp(-E*(2-alpha)/Ep) with alpha = 1.051 (-0.081, +0.078) and Ep = 253 (-19, +22) keV (chi2 = 66.2/60 dof). Fitting by a GRBM (Band) model yields: the low-energy photon index alpha = -1.025 +/- 0.084, the high energy photon index beta < -2.55, the peak energy Ep = 243(-20, +24) keV (chi2 = 64.5/59 dof). All the quoted errors are at the 90% confidence level. The Konus-Wind light curve of this GRB is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB070824_T74999/