EDP Sciences
Free access
Volume 401, Number 2, April II 2003
Page(s) 491 - 498
Section Galactic structure and dynamics
DOI http://dx.doi.org/10.1051/0004-6361:20030143

A&A 401, 491-498 (2003)
DOI: 10.1051/0004-6361:20030143

The dark burst 010214 with BeppoSAX: Possible variable absorption and jet X-ray emission

C. Guidorzi1, F. Frontera1, 2, E. Montanari1, 3, L. Amati2, L. A. Antonelli4, J. J. M. in 't Zand5, E. Costa6, R. Farinelli1, M. Feroci6, J. Heise5, N. Masetti2, L. Nicastro7, M. Orlandini2, E. Palazzi2 and L. Piro6

1  Dipartimento di Fisica, Università di Ferrara, via Paradiso 12, 44100 Ferrara, Italy
2  Istituto Astrofisica Spaziale e Fisica Cosmica, Sezione di Bologna, CNR, via Gobetti 101, 40129 Bologna, Italy
3  ITA "I. Calvi", Finale Emilia (MO), Italy
4  Osservatorio Astronomico di Roma, via Frascati 33, Monteporzio 00040, Italy
5  Space Research Organization in the Netherlands, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
6  Istituto Astrofisica Spaziale e Fisica Cosmica, Sezione di Roma, CNR, via Fosso del Cavaliere, 00133 Roma, Italy
7  Istituto Astrofisica Spaziale e Fisica Cosmica, Sezione di Palermo, CNR, via U. La Malfa 153, 90146 Palermo, Italy

(Received 10 October 2002 / Accepted 22 January 2003 )

We report on the prompt and afterglow emission observations of the dark burst GRB010214 with BeppoSAX. The prompt emission shows possible evidence of variable absorption from $N_{\rm H} = 3.0^{+5.1}_{-2.0} \times
10^{23}$  cm -2 in the first 6 s of the event to a value consistent with the Galactic column density ( $N_{\rm H}^{\rm G} = 2.66\times 10^{20}$ cm -2) in the GRB direction. An X-ray afterglow emission in the 2-10 keV energy band was detected with BeppoSAX, but an analogue search at lower wavelengths (optical, IR and radio) was unsuccessful. The X-ray afterglow spectrum is consistent with a power-law with Galactic absorption. The light curve shows a complex decay, if the tail of the prompt emission is assumed as the onset of the afterglow: if the origin of the afterglow is coincident with the GRB onset, a bump before ~ $3\times10^4$ s is inferred, while if the afterglow is assumed to start later, a steepening of the power-law light curve at $t\sim 3\times10^4$ s is deduced. We discuss these results in the light of the current models of afterglows and the possible origin of the GRB darkness. Finally, we tentatively derive an estimate of the burst redshift.

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

Offprint request: C. Guidorzi, guidorzi@fe.infn.it

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