This file contains "B" and "C". Due to a naming confusion, there is no "A" burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8133 SUBJECT: GRB 080825B: GRB Localization by SuperAGILE DATE: 08/08/25 20:11:07 GMT FROM: Marco Feroci at IASF/INAF Y. Evangelista, P. Soffitta, E. Del Monte, I. Donnarumma, M. Feroci, F. Lazzarotto, L. Pacciani, E. Costa, I. Lapshov, M. Rapisarda (INAF/IASF Rome), A. Giuliani, S. Vercellone, A. Chen, S. Mereghetti, A. Pellizzoni, F. Perotti, F. Fornari, P. Caraveo (INAF/IASF Milan), A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C. Labanti, F. Fuschino, M. Marisaldi, M. Galli, (INAF/IASF Bologna), M. Tavani, G. Pucella, F. D'Ammando, V. Vittorini, A. Argan, A. Trois (INAF/IASF Rome), G. Barbiellini, F. Longo (INFN Trieste), P. Picozza, A. Morselli (INFN Roma-2), M. Prest, E. Vallazza (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), and P. Giommi, C. Pittori, B. Preger, P. Santolamazza, F. Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team, report: "SuperAGILE detected a gamma ray burst on 25 August 2008, at 17:46:40 UT. The event was approximately 10 degrees off-axis, with a duration of about 50 s in the 20-60 keV energy range, with a multi-peaked structure. The burst position was reconstructed as (RA, Dec) (209.281 deg, -68.943 deg), which is: RA(J2000) = 13h 57m 07.42s Dec(J2000) = -68d 56' 34.0" with an uncertainty of 3' radius. The given uncertainty accounts for both the statistical and systematic errors. An analysis of the AGILE Gamma Ray Imager (GRID) data is in progress." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8135 SUBJECT: GRB 080825B - optical counterpart candidate DATE: 08/08/26 01:15:20 GMT FROM: Christina Thoene at Niels Bohr Institute,DARK Cosmo Ctr Christina C. Thoene (DARK/NBI), Antonio de Ugarte Postigo (ESO) and Davide Ricci (Univ. of Liege) report: We observed the complete 3' error box of the SuperAGILE GRB 080825B (Evangelista et al., GCN 8133) using the Danish 1.54m + DFOSC at La Silla (Chile) starting Aug. 25 at 23:18:31 UT (5.53 hours after the burst). In the first I-band frame we detect a new source not present in the DSS-2 catalogue at the following coordinates (J2000.0 +/- 0.7"): RA: 13:56:48.22 DEC: -68:57:18.5 for which we measure an I-band magnitude of 17.4 +/- 0.2 as compared to several USNO-B1 stars. A finding chart can be found at: http://www.sc.eso.org/~adeugart/GRB/080825/080825.jpg Further observations and analysis are ongoing to establish the connection to the GRB and the fading of the object. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8137 SUBJECT: GRB080825: Afterglow confirmation and redshift estimate DATE: 08/08/26 02:43:47 GMT FROM: Christina Thoene at Niels Bohr Institute,DARK Cosmo Ctr Antonio de Ugarte Postigo (ESO), Christina C. Thoene (DARK/NBI) and Davide Ricci (Univ. of Liege) report: We obtained further observations of the candidate optical counterpart of GRB 080825B (Evangelista et al., GCN 8133) in Bessel-UBVRI bands. The object is found to be fading in a series of I band images. From 23:18 UT to 01:41 UT, the candidate afterglow faded from 17.4+/-0.2 to 18.1+/-0.2 mag compared to several USNO-B stars, confirming the reality of the afterglow proposed by Thoene et al. (GCN 8135). Furthermore the object is detected in V, R and I band, but not in U and B. We therefore derive a redshift limit of z>3 if the nondetection is due to Lyman alpha absorption or z>4.3 if due to the Lyman limit. Further analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8140 SUBJECT: GRB 080825B: Swift-XRT team analysis DATE: 08/08/27 02:06:25 GMT FROM: Claudio Pagani at PSU/Swift-XRT C. Pagani reports on behalf of the Swift-XRT team: We have analyzed the Swift XRT data on the field of the AGILE detected GRB 080825B (Evangelista et al., GCN Circ. 8133), consisting of 7.5 ks of Photon Counting data collected from T0+44 ks to T0+78 ks. We detect a point source at the position of the optical afterglow (Thoene et al., GCN Circ. 8135). During the XRT observations the source faded from an initial count rate of 0.05 counts/s to a later count rate of 0.01 counts/s. The spectrum from the PC data can be fitted by an absorbed power law model with photon index of 2.1 and the absorption consistent with the Galactic value along the line of sight (2.10e21 cm^-2, Kalberla et al. 2005). The average observed (unabsorbed) flux of the PC mode data is 5.8e-13 (9.0e-13) ergs cm^-2 s^-1. This Circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8141 SUBJECT: GRB080825C: GLAST Burst Monitor detection DATE: 08/08/27 03:38:23 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (NASA/ORAU) and V. Connaughton (UAH) report on behalf of the Fermi GBM Team: "At 14:13:48 UT on 25 August 2008, the Fermi GBM triggered and located GRB 080825C (trigger 241366429 / 080825.593). The on-ground calculated location, using the GBM trigger data, is RA = 232.2, Dec = -4.9 (J2000 degrees, equivalent to 15h 29m, -4d 54'), with an uncertainty of 1.5 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 60 degrees. This GRB has several peaks, with T90 (50-300 keV) = 22 s and T50 (50-300 keV) = 12 s. The time-averaged spectrum (8-910 keV) from T0 to T0+22.1 s is best fit by a Band function with Epeak = 155 +/- 5 keV, alpha = -0.39 +/- 0.04, and beta = -2.34 +/- 0.09. The fluence (50-300 keV) is 2.4E-5 erg/cm^2. The spectral analysis results presented above are preliminary; the final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8142 SUBJECT: Konus-Wind observation of GRB 080825B DATE: 08/08/27 13:26:45 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, D. Svinkin, M. Ulanov and T. Cline, on behalf of the Konus-Wind team report: The most intense part of the GRB 080825B localized by SuperAGILE (Evangelista et al., GCN 8133) triggered Konus-Wind at T0=64012.487 s UT (17:46:52.487). The burst light curve shows a weak emission starting at ~T0-70s, the main multipeaked part (from ~T0-5s to ~T0+15s), and an extended emission seen up to ~T0+40s. As observed by Konus-Wind the burst had a fluence of 7.81(-0.70, +0.83)x10^-6 erg/cm2, and a 256-ms peak flux measured from T0-0.080 s of 1.21(-0.31, +0.32)x10^-6 erg/cm2/s (both in the 20 keV - 1 MeV energy range). The spectrum of the most intense part (from T0 to T0+16.640 s) is well fitted (in the 20 keV-1 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.13(-0.36, +0.40), and Ep = 72(-9, +11) keV (chi2 = 40.0/51 dof). Fitting by GRBM (Band) model yields: the low-energy photon index is alpha = -1.05(-0.38, +0.56), the high energy photon index beta < -2.52, the peak energy Ep = 71(-9, +11) keV (chi2 = 38.8/50 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/GRB080825_T64012/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8143 SUBJECT: GRB 080825B: pseudo-z= 0.83 from prompt emission spectrum DATE: 08/08/27 14:29:29 GMT FROM: Alexandre Pelangeon at LATT,OMP,Toulouse We used the spectral parameters of GRB 080825B provided by Golenetskii et al. (GCNC 8142) to compute the spectral pseudo-redshift(**) of this burst localized by SuperAGILE (Evangelista et al., GCN 8133). We find a pseudo-redshift pz= 0.83 ± 0.30 (**) cf. http://www.ast.obs-mip.fr/grb/pz //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8158 SUBJECT: GRB080825B: Swift/UVOT Upper Limits DATE: 08/08/29 01:10:54 GMT FROM: Peter Brown at PSU P. J. Brown (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT observed the field of GRB 080825B starting about 45 ks after the SuperAGILE detection (Evangelista et al., GCN Circ. 8133). We do not detect the optical afterglow seen by Thoene et al. (GCN Circ. 8135) in any of the UVOT filters down to the following 3 sigma upper limits. Filter T_start(s) T_stop Exp(s) MagLimit white 49916 50823 885 >22.1 uvw2 44237 78448 1903 >21.5 uvm2 61477 67242 988 >20.8 uvw1 67248 73020 1036 >20.9 u 73027 73522 483 >20.8 b 49004 49911 885 >21.2 v 45144 61472 1234 >20.5 The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E(B-V) ~ 0.25 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383,627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8183 SUBJECT: GRB080825C: Fermi-LAT observations DATE: 08/09/05 17:45:46 GMT FROM: Aurelien Bouvier at Stanford A. Bouvier (SLAC), D. Band (GSFC), J. Bregeon (INFN Pisa), J. Chiang (SLAC), S. Cutini (ASDC), B. Dingus (LANL), N. Gehrels (GSFC), Y. Fukazawa (Hiroshima U), M. Hayashida (SLAC), F. Longo (INFN Trieste), J. McEnery (GSFC), M. Ohno (JAXA), N. Omodei (INFN Pisa), V. Pelassa (LPTA), F. Piron (LPTA), D. Sanchez (LLR), J. Scargle (NASA Ames), H. Tajima (SLAC), T. Tanaka (SLAC), G. Thayer (SLAC) on behalf of the Fermi LAT team: We report a detection by the Fermi Large Area Telescope (LAT) of emission from GRB080825C, which was triggered by the Fermi Gamma-ray Burst Monitor (GBM) at 14:13:48 UT on August 25th 2008 (GCN 8141 by Van der Horst et al.). The angle of the GBM best localization (ra, dec=232.2,-4.6) with the LAT boresight was 60 deg at the time of the trigger which is on the edge of our field of view. The data from the Fermi LAT shows a significant increase in the event rate within 10 degree of the GBM localization and up to 35 seconds after the GBM trigger that is spatially and temporally correlated with the GBM emission with a significance of more than 5 sigma. All the LAT events detected during the GBM emission have energies below 1 GeV. The best LAT on-ground localization is found to be RA,DEC=233.96,-4.72 deg with a 90% containment radius of 1.5 deg (statistical+systematics; 68% containment radius: 0.95 deg) which is consistent with the GBM localization. This circular is an official product of the Fermi LAT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8184 SUBJECT: GRB 080825C: Fermi GBM Spectral Analysis DATE: 08/09/05 18:01:27 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (NASA/ORAU), V. Connaughton and M.S. Briggs (UAH) report on behalf of the Fermi GBM Team: "We have performed time-resolved spectroscopy of GRB 080825C (GCN 8141, GCN 8183). The main emission up to 23 seconds is best fit by the Band function. Time-resolved spectra of this emission period display the commonly observed hard-to-soft spectral evolution, with Epeak decreasing from 170 to 110 keV, while the spectral indices remain roughly constant at alpha ~ -0.4 and beta ~ -2.4, consistent with the time-averaged spectral result (GCN 8141). Weaker emission following this period lasts a further 11 seconds and deviates from this spectral behaviour. The spectrum of this tail over the energy range 8-900 keV is best fit by a single power law with index -1.41 +/- 0.09. The spectral analysis results presented above are preliminary; the final results will be published in the GBM GRB Catalog."