SIMBAD references

On January 6th 2004, the IBAS burst alert system triggered the 8th gamma-ray burst (GRB) to be located by the INTEGRAL satellite. The position was determined and publicly distributed within 12s, prompting ESA's XMM-Newton to execute a ToO observation just 5h later, during which an X-ray afterglow was detected. The GRB had a duration ∼52s with two distinct pulses separated by ∼42s. Here we present the results of imaging and spectral analyses of the prompt emission from INTEGRAL data and the X-ray afterglow from XMM-Newton data. The γ-ray spectrum is consistent with a single power-law of photon index -1.72±0.15. The fluence (20-200keV) was 8.2x10^–7erg/cm². The X-ray afterglow (F_ν(t)∝ν^–βX_^t-δ^) was extremely hard with β_X=0.47±0.01 and δ=1.46±0.04. The 2-10keV flux 11h after the burst was 1.1x10^–12erg/cm²/s. The time profile of the GRB is consistent with the observed trends from previous analysis of BATSE GRBs. We find that the X-ray data are not well-fit by either a simple spherical fireball or by a speading jet, expanding into a homogeneous medium or a wind environment. Based on previously determined correlations between GRB spectra and redshift, we estimate a redshift of ∼0.9^+0.5_–0.4 (1σ) and a lower limit on the isotropic radiated energy of ∼5x10⁵¹erg in this burst.