//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15607 SUBJECT: GRB 131224A: A short GRB detected by INTEGRAL DATE: 13/12/24 18:17:19 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), E.Bozzo, C.Ferrigno, D.Malishev (ISDC, Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report: a short gamma ray burst lasting about 0.8 s has been detected by IBAS in the IBIS/ISGRI data at 16:54:37 UT of 24 December. The refined coordinates (J2000) are: R.A.= 296.8337 deg DEC.= +31.6677 deg with an uncertainty of 2 arcmin (90% c.l.). The burst had a peak flux of about 1 counts/cm2/s (20-200 keV, 0.1-s integration time) and a fluence in the same energy range of about 3x10e-8 erg/cmq. A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15608 SUBJECT: GRB 131224A: MASTER-Net early optical observations DATE: 13/12/25 08:14:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, D.Denisenko, A.Sankovich Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB131224A 33 sec after notice time and 39 sec after trigger time at 2013-12-24 16:55:24 UT in two polarizations. Observations were made on high (z=75 deg) zenith distance and on the extremely stars rich field (with galactic latitude b=3 deg). On our first (10s exposure) set we haven`t found optical transient within INTEGRAL error-box (S.Mereghetti et. al. GCN 15607). The 5-sigma upper limit has been about 15.5 mag The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15610 SUBJECT: GRB 131224A: Swift-XRT observation DATE: 13/12/25 21:21:07 GMT FROM: Ben Gompertz at U.of Leicester B.P Gompertz, K.L. Page (U. Leicester) and M. De Pasquale (UCL-MSSL) report on behalf of the Swift-XRT team: We report on Swift-XRT observations of the field of the INTEGRAL discovered GRB 131224A (Mereghetti et al. GCN Circ 15607), starting 10.8 ks after the trigger. XRT began observing the field on 2013-12-24 at 19:53:56 UT (10.8 ks after trigger), with an exposure time of of 3.96 ks. No source is detected within the INTEGRAL error circle. The 3-sigma upper limit on the count rate is 3.5E-03 cts/s, which is 1.4E-13 erg cm^-2 s^-1 using a typical flux conversion of 4E-11 erg cm^-2 count^-1. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15615 SUBJECT: GRB 131224A: Swift/UVOT Upper Limits DATE: 13/12/26 17:44:22 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and M. De Pasquale (UCL-MSSL) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 131224A 10748 s after the INTEGRAL trigger (Mereghetti et al., GCN Circ. 15607). The field is very crowded and no optical afterglow consistent with the INTEGRAL position is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag u 10748 18662 3918 >21.1 The magnitudes in the table are not corrected for the strong Galactic extinction due to the reddening of E(B-V) = 0.96 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15626 SUBJECT: GRB 131224A: 5.8 GHz VLA observations DATE: 13/12/27 23:35:41 GMT FROM: Wen-fai Fong at CFA W. Fong, B. A. Zauderer and E. Berger (Harvard) report: "We observed the field of the INTEGRAL short-duration GRB 131224A (Mereghetti et al., GCN 15607) with the Karl G. Jansky Very Large Array (VLA). We obtained two sets of 1-hour observations beginning on 2013 Dec 24.907 UT and 2013 Dec 26.971 UT (0.202 and 2.267 days post-burst, respectively) at a mean frequency of 5.8 GHz. We find no evidence for variability within the INTEGRAL error circle to a 3-sigma limit of 33 microJy at the time of the two observations. We thank the VLA staff for quickly executing these observations."