GRB081224A

This page lists all entries on GRB081224A in GRBweb

Summary Fermi GBM GCN 8723 GCN 8725 GCN 8726 GCN 8739

Summary table
Variable Value Source
GRB_name_Fermi GRB081224887
T0 21:17:55.410 UTC GCN_circulars,Fermi GBM Det
ra 213.1494° GCN_circulars,Swift-XRT Other
decl 74.1999° GCN_circulars,Swift-XRT Other
T90 16.448 s Fermi_GBM
T90_error 1.159 s Fermi_GBM
T90_start 21:17:56.150 UTC Fermi_GBM
fluence 3.76e-05 erg/cm² Fermi_GBM
fluence_error 1.69e-07 erg/cm² Fermi_GBM
T100 17.188 s
GBM_located False
mjd 54824.887446875 GCN_circulars,Fermi GBM Det
Fermi GBM table
GRB_name_Fermi GRB081224887
trigger_name bn081224887
ra 201.7000°
decl 75.1000°
pos_error 2.45e+00°
datum 2008-12-24
t_trigger 21:17:55.414 UTC
T90 16.448 s
T90_error 1.159 s
T90_start 21:17:56.150 UTC
fluence 3.76e-05 erg/cm²
fluence_error 1.69e-07 erg/cm²
flux_1024 2.38e+01 erg/cm²/s
flux_1024_error 2.79e-01 erg/cm²/s
flux_1024_time 2.53e+00 erg/cm²/s
flux_64 2.67e+01 erg/cm²/s
flux_64_error 1.15e+00 erg/cm²/s
GCN 8723 table
GRB_name GRB081224A
GCN_number 8723
Detection_method Fermi GBM Det
t_trigger 21:17:55.410 UTC
ra 206.2000°
decl 74.2330°
Circular_text TITLE: GCN CIRCULAR NUMBER: 8723 SUBJECT: GRB 081224: Fermi GBM Detection & LAT Localization DATE: 08/12/25 00:43:55 GMT FROM: Valerie Connaughton at MSFC Colleen Wilson-Hodge (MSFC) and Valerie Connaughton (UAH) on behalf of the Fermi-GBM team, Francesco Longo (INFN Trieste) and Nicola Omodei (INFN Pisa) on behalf of the Fermi LAT team. "On 21:17:55.41 UT of Dec 24 2008 GBM detected a bright GRB. Preliminary analysis of the real-time Fermi GBM data from Trigger number 251846276/ GRB 081224887 / GRB 081224 shows that this is a FRED (Fast Rise Exponential Decay) lasting approximately 50 seconds with a peak of FWHM 15 sec long. It is located to a position of RA=206.2, Dec= 73.3 with statistical uncertainty 1 deg (and an estimated systematic uncertainty of 2-3 deg) which places it at 16 deg to the LAT boresight. The Large Area Telescope (LAT) also provided a tentative onboard localization: RA=213.367, DEC=74.233 (J2000) corresponding to: RA: +14h 13m 28s (J2000), DEC: +74d 13' 60" (J2000) with on board estimated error of 36 arcmin (statistical only). The current estimated onboard systematic error is 1 deg. The estimated LAT position is 2.2 deg from the ground GBM location and may be considered more reliable. Accurate LAT localization and spectral analysis will await the downlink of both LAT and GBM data which could take several hours. We further report that the Fermi Observatory executed a maneuver following this trigger and will track the burst location for the next 5 hours, subject to Earth-angle constraints. We encourage follow up observations. The Fermi LAT point of contact for this burst is Francesco Longo (francesco.longo@ts.infn.it). The Fermi GBM point of contact is Valerie Connaughton (valerie@nasa.gov) The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. This message can be cited."
GCN 8725 table
GRB_name GRB081224A
GCN_number 8725
Detection_method Swift-XRT Other
ra 213.1494°
decl 74.1999°
Circular_text TITLE: GCN CIRCULAR NUMBER: 8725 SUBJECT: GRB 081224: Swift-XRT observation DATE: 08/12/25 10:17:22 GMT FROM: Kim Page at U.of Leicester K.L. Page and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift performed a Target of Opportunity follow-up observation of the Fermi GBM and LAT burst GRB 081224 (Wilson-Hodge et al., GCN Circ. 8723), starting 18 ks after the trigger. There is a faint X-ray source (~6.7x10^-3 count s^-1) within the XRT field of view, detected in the 3.6 ks of data collected so far. Using 1193 s of XRT Photon Counting mode data and 1 UVOT image, 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 = 213.1494, 74.1999, which is equivalent to: RA (J2000): 14 12 35.85 Dec (J2000): +74 11 59.5 with an uncertainty of 3.4 arcsec (radius, 90% confidence). However, we note that the uncertainty on the LAT position (36 arcmin) is larger than the XRT field of view, so Swift has not observed the complete error circle. We also cannot say whether the XRT source is fading at this time. This circular is an official product of the Swift-XRT team.
GCN 8726 table
GRB_name GRB081224A
GCN_number 8726
Detection_method retraction
Circular_text TITLE: GCN CIRCULAR NUMBER: 8726 SUBJECT: GRB081224: LAT retraction DATE: 08/12/25 14:50:33 GMT FROM: Julie McEnery at UMBC/GSFC Julie McEnery (NASA/GSFC) reports on behalf of the LAT collaboration On-ground analysis of GRB 081224 did not confirm the tentative LAT on-board detection reported in GCN 8723. The apparent onboard excess was likely a statistical fluctuation.
GCN 8739 table
GRB_name GRB081224A
GCN_number 8739
Detection_method Suzaku WAM Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 8739 SUBJECT: GRB 081224: Suzaku WAM observation of the prompt emission DATE: 08/12/27 03:55:50 GMT FROM: Hidenori Hayasi at Miyazaki U H. Hayashi E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono (Univ. of Miyazaki) A. Endo, M. Tashiro, Y. Terada, Y. Urata, K. Onda, N. Kodaka, K. Morigami, T. Sugasahara, W. Iwakiri (Saitama U.), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Sugita, K. Yamaoka (Aoyama Gakuin U.), M. Ohno, M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), Y.E. Nakagawa, T. Tamagawa (RIKEN), Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira (Hiroshima U.), S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report: The long, bright GRB 081224 (Fermi-GBM trigger #251846276; Colleen et al., GCN 8725) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2008-12-24 21:17:55.214 UT (=T0). The observed light curve shows a FRED-like peak structure starting at T0-0.2s, ending at T0+19.8s with a duration (T90) of about 10.3 seconds. The fluence in 100 - 1000 keV was 2.87(+0.09, -0.04) erg/cm^2. The 1-s peak flux measured from T0+2s - T0+3s was 16.95(+0.91, -0.55) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-0.2s to T0+19.8s is well fitted by a power-law with exponential cutoff model dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha 0.83(+0.27, -0.28), and Epeak 447(+57, -40) keV (chi^2/d.o.f. = 19/22). All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included. The light curves for this burst are available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html