EDP Sciences
Free access
Issue
A&A
Volume 432, Number 2, March III 2005
Page(s) 467 - 473
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20041267


A&A 432, 467-473 (2005)
DOI: 10.1051/0004-6361:20041267

INTEGRAL and XMM-Newton observations of GRB 040106

L. Moran1, 2, S. Mereghetti3, D. Götz3, L. Hanlon1, A. von Kienlin4, B. McBreen1, A. Tiengo3, R. Preece5, O. R. Williams6, K. Bennett6, R. M. Kippen7, S. McBreen1 and S. McGlynn1

1  Department of Experimental Physics, University College Dublin, Dublin 4, Ireland
2  School of Physics and Astronomy, University of Southampton, Southampton, UK
    e-mail: lmoran@astro.soton.ac.uk
3  Istituto di Astrofisica Spaziale e Fisica Cosmica - CNR, via Bassini 15, 20133 Milano, Italy
4  Max-Planck-Institut für extraterrestrische Physik, 85748 Garching, Germany
5  Department of Physics, University of Alabama at Huntsville, USA
6  Science Operations and Data Systems Division of ESA/ESTEC,SCI-SDG, 2200 AG Noordwijk, The Netherlands
7  Space and Remote Sensing Sciences, Los Alamos National Laboratory, USA

(Received 10 May 2004 / Accepted 15 November 2004)

Abstract
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 12 s, prompting ESA's XMM-Newton to execute a ToO observation just 5 h later, during which an X-ray afterglow was detected. The GRB had a duration ~52 s with two distinct pulses separated by ~42 s. 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 $\gamma$-ray spectrum is consistent with a single power-law of photon index -1.72 $\pm$ 0.15. The fluence (20-200 keV) was 8.2 $\times$ 10-7 erg cm-2. The X-ray afterglow ( $F_{\nu}(t) \propto {\nu}^{-{\beta_{\rm X}}} {t}^{-{\delta}}$) was extremely hard with $\beta_{\rm X} = 0.47$ $\pm$ 0.01 and $\delta = 1.46$ $\pm$ 0.04. The 2-10 keV flux 11 h after the burst was 1.1 $\times$ 10-12 erg cm-2 s-1. 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 (1$\sigma$) and a lower limit on the isotropic radiated energy of ~5 $\times$ 1051 erg in this burst.


Key words: gamma-rays: bursts -- gamma-rays: observations

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