//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10298 SUBJECT: GRB 091230: a long GRB detected by INTEGRAL DATE: 09/12/30 07:57:12 GMT FROM: Sandro Mereghetti at IASF/CNR D.Gotz (CEA-Saclay), S. Mereghetti, A.Paizis (IASF-Milano), E.Bozzo, L.Gibaud, C.Ferrigno, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: A GRB with duration of about 120 s has been detected by IBAS in IBIS/ISGRI data at 06:27:30 UT on December 30. The refined coordinates (J2000) are: RA: 132.9146 [degrees] DEC: -53.8825 [degrees] with an uncertainty of 2.5 arcmin (90% c.l.). A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10299 SUBJECT: GRB 091230: GROND optical/NIR afterglow candidate DATE: 09/12/30 13:00:36 GMT FROM: Thomas Kruehler at MPE/MPI R. Filgas, T. Kruehler and J. Greiner (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 091230 (INTEGRAL trigger #5967, D. Gotz et al., GCN #10298) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile). Observations started on 30 Dec. 2009 at 06:30:27 UT, 2.9 min after the burst. Image subtraction reveals a variable point source inside the INTEGRAL error circle (D. Gotz et al., GCN #10298) at RA (J2000.0) = 08:51:39.18 DEC (J2000.0) = -53:53:52.7 with an uncertainty of 0.5" in each coordinate. This is 56" from the refined INTEGRAL position. Preliminary photometry yields the following magnitudes in stacked images: Filter T_mid[s] Exp[s] AB Mag MagErr --------------------------------------- g' 390 4x 66 21.63 0.07 r' 390 4x 66 20.76 0.04 i' 390 4x 66 20.45 0.05 z' 390 4x 66 20.22 0.05 J 403 24x 10 19.75 0.12 H 403 24x 10 19.58 0.14 K 403 24x 10 19.26 0.15 The quoted error is statistical only. There is an additional systematic error in the absolute calibration using the GROND zeropoints and 2MASS field stars which is expected to be in the 0.1 to 0.2 mag range. The object fades by two magnitudes to r' = 22.8 ± 0.1 until the end of our optical observations two hours after the trigger - thus we propose this object as the optical/NIR afterglow of GRB 091230. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10300 SUBJECT: GRB 091230: Swift-XRT observation DATE: 09/12/31 01:45:38 GMT FROM: Andy Beardmore at U Leicester A. P. Beardmore (U. Leicester) and H. A. Krimm (CRESST/GSFC/USRA) report on behalf of the Swift-XRT team: At 2009-12-30 15:25UT Swift performed a TOO observation of the INTEGRAL discovered long GRB 091230 (Gotz et al., GCN Circ. 10298). In 3.7 ks of XRT Photon Counting (PC) mode data, taken from 32.3 ks to 39.4 ks after the INTEGRAL trigger, we find an X-ray source within the INTEGRAL error circle, with a 0.3-10 keV count rate of 0.01 count/s. Using 1096 s of PC mode data and 1 UVOT image, the enhanced XRT position for this source (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue, as described by Goad et al., 2007, A&A, 476, 1401 and Evans et al., 2009, MNRAS, 397, 1177) is: RA, Dec = 132.91150, -53.89780, which is equivalent to: RA (J2000): 08 51 38.77 Dec(J2000): -53 53 52.0 with an uncertainty of 2.7 arcsec (radius, 90% confidence). This position lies 3.8 arcsec from the location of the Grond optical/NIR afterglow candidate (Filgas et al., GCN Circ. 10299). At this stage, we cannot tell whether the X-ray source is fading, but its coincidence with the Grond candidate suggests it is likely the X-ray counterpart to GRB 091230. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020124. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10302 SUBJECT: GRB 091230: Swift/UVOT Observations DATE: 09/12/31 18:50:34 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and H. A. Krimm (CRESST/GSFC/USRA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 091230 32291 s after the Integral detection (Gotz et al., GCN Circ. 10298). We do not detect the afterglow reported by GROND (Filgas et al., GCN Circ. 10299) and Swift-XRT (Beardmore et al., GCN Cic. 10300). Preliminary 3-sigma upper limits are: FILTER T_start(s) T_stop Exposure Mag/3UL ============================================================= white 32291 42824 3898 >22.2 The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.36 (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).