//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8305 SUBJECT: GRB081001: SuperAGILE Localization of a long GRB DATE: 08/10/01 22:55:08 GMT FROM: Marco Feroci at IASF/INAF F. Lazzarotto, E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci, L. Pacciani, P. Soffitta, 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 1st October 2008, at 21:17:42 UT. The event had a duration of about 40 s in the 20-60 keV energy range, with a first 10-s long bright peak, followed by a second broad peak about 20s apart. Assuming a Crab-like energy spectrum, the peak flux on 1-s timescale was about 6 ph/cm2/s or 5E-07 erg/cm2/s (20-60 keV). The burst position was reconstructed as (RA, Dec) (276.576 deg, -8.754 deg), which is: RA(J2000) = 18h 26m 18.34s Dec(J2000) = -8d 45' 14.65" 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: 8306 SUBJECT: GRB081001: optical limit from ASH-Centurion DATE: 08/10/02 02:24:13 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada Martin Jelinek, Rene Duffard, Pablo Santos Sanz and Alberto J. Castro Tirado (IAA CSIC Granada) report on behalf of a larger collaboration: We observed the errorbox of the SuperAGILE GRB081001 (Lazzarotto et al., GCN 8305) with the 40cm ASH-Centurion telescope at Cerro Burek in Argentina starting at 23:28 UT. The combined 600s unfiltered image with exposure mid-time 2.30h after the GRB trigger does not reveal any new source down to limiting magnitude of ~19.0 in comparison to the Digitized Sky Survey. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8307 SUBJECT: GRB 081001: Swift-XRT position DATE: 08/10/02 16:14:48 GMT FROM: Kim Page at U.of Leicester K.L. Page (U. Leicester) and H.A. Krimm (CRESST/GSFC/USRA) report on behalf of the Swift-XRT team: Swift-XRT started observing the field of the SuperAGILE GRB 081001 (Lazzarotto et al., GCN Circ. 8305) 15.5 ks after the trigger. A single, fading source was identified within the SuperAGILE error circle, which we identify as the X-ray afterglow. Using 4307 s of XRT Photon Counting mode data and 4 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 276.59076, -8.71903 which is equivalent to: RA (J2000): 18 26 21.78 Dec (J2000): -08 43 08.5 with an uncertainty of 2.0 arcsec (radius, 90% confidence). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8308 SUBJECT: GRB 081001: Swift UVOT Observations DATE: 08/10/02 17:29:21 GMT FROM: Erik Hoversten at Swift/Penn State E. A. Hoversten (PSU), and H.A. Krimm (CRESST/GSFC/USRA) report on behalf of the Swift UVOT team: The Swift/UVOT began observations of the field of GRB 081001 14.5 ks after the SuperAGILE dectection (Lazzarotto et al., GCN Circ. 8305). No afterglow is detected within the Swift XRT error circle (Page et al., GCN 8307) in any of the observed UVOT filters. UVOT magnitude 3-sigma upper limits are reported in the following table: Filter T_start T_stop Exp(s) Mag (3-sigma upper limit) ------------------------------------------------------------- v 16285 22214 350 > 19.84 b 15213 21209 416 > 20.90 u 14997 20992 416 > 20.51 uvw1 14568 20776 834 > 20.84 uvm2 16502 16696 191 > 19.81 uvw2 15431 22064 1670 > 21.65 The quoted upper limits have not been corrected for the large expected Galactic extinction along the line of sight of E(B-V) = 2.63 mag (Schlegel et al., 1998). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8310 SUBJECT: GRB 081001: Observations from OSN DATE: 08/10/03 01:29:37 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (ESO, Santiago), F. Aceituno, M. Jelínek, J. Gorosabel and A.J. Castro-Tirado (IAA-CSIC, Granada) on behalf of a larger collaboration report, We have observed the field of the SuperAGILE GRB 081001 (Lazzarotto et al., GCN 8305) and in particular the Swift/XRT error box (Page et al., GCN 8307) from the 1.5m OSN telescope at Sierra Nevada Observatory in Granada (Spain). The observation consisted of 3x300s I-band exposures with a mean time of Oct 2.8348 UT (22.7 hours after the burst). We detect just one source on the edge of the XRT error box, located at the following coordinates (J2000 +/- 0.7"): R.A.: 18:26:21.65 Dec.: -08:43:07.6 With a magnitude of I = 19.90+/-0.26 as compared to several USNO-B1 stars. A finding chart (with the object is marked as A) can be found in: http://www.sc.eso.org/~adeugart/GRB/081001/081001.gif No variability can be established at this point. Rechecking of the unfiltered image reported by Jelínek et al. (GCN 8306) does not show any significant emission at the location of the object. Further observations would be needed in order to determine any relation of this source with the GRB. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8322 SUBJECT: GRB 081001: Further observations from OSN DATE: 08/10/04 01:07:27 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (ESO, Santiago), F. Aceituno, M. Jelínek, J. Gorosabel and A.J. Castro-Tirado (IAA-CSIC, Granada) on behalf of a larger collaboration report, We have observed again the field of GRB 081001 (Lazzarotto et al., GCN 8305, Page et al., GCN 8307) from the 1.5m OSN telescope at Sierra Nevada Observatory in Granada (Spain). In a combined 5x300s exposure in I-band we still detect the source reported in our previous GCN (de Ugarte Postigo et al. GCN 8310) with no variation in brightness indicating that it is probably unrelated with the GRB. No further source is detected within the XRT error box. The 3-sigma limiting magnitudes of the images obtained from OSN are I > 20.7 0.95 days after the burst and I > 21.2 1.94 days after the burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8353 SUBJECT: Konus-Wind observation of GRB 081001 DATE: 08/10/10 14:05:56 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 GRB 081001 localized by SuperAGILE (Lazzarotto et al., GCN 8305) triggered Konus-Wind at T0=76663.649 s UT (21:17:43.649). The burst light curve shows a main pulse with a duration of ~6 s followed by a much weaker pulse at T0+~30 s with a duration of ~10 s. As observed by Konus-Wind the burst had a fluence of 9.70(-0.86, +1.00)x10^-6 erg/cm2, and a 64-ms peak flux measured from T0+0.688 s of 5.63(-1.12, +1.16)x10^-6 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The spectrum of the main pulse (from T0 to T0+8.448 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 = -0.99(-0.18, +0.21), and Ep = 239(-32, +45) keV (chi2 = 54.9/61 dof). Fitting by GRBM (Band) model yields: the low-energy photon index is alpha = -0.95(-0.21, +0.48), the high energy photon index beta < -2.14, the peak energy Ep = 227(-70, +52) keV (chi2 = 54.1/60 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/GRB081001_T76663/