Intrinsic properties of a complete sample of HETE-2 gamma-ray bursts. A measure of the GRB rate in the Local Universe
astro-ph
/ Authors
A. Pélangeon, J. -L. Atteia, Y. E. Nakagawa, K. Hurley, A. Yoshida, R. Vanderspek, M. Suzuki, N. Kawai, G. Pizzichini, M. Boër
and 25 more authors
J. Braga, G. Crew, T. Q. Donaghy, J. P. Dezalay, J. Doty, E. E. Fenimore, M. Galassi, C. Graziani, J. G. Jernigan, D. Q. Lamb, A. Levine, J. Manchanda, F. Martel, M. Matsuoka, J. -F. Olive, G. Prigozhin, G. R. Ricker, T. Sakamoto, Y. Shirasaki, S. Sugita, K. Takagishi, T. Tamagawa, J. Villasenor, S. E. Woosley
/ Abstract
Aims: Taking advantage of the forthcoming Catalog of the HETE-2 mission, the aim of this paper is to evaluate the main properties of HETE-2 GRBs - the E_peak, the T_90 and the E_iso - in their source frames and to derive their unbiased distribution. Methods: We first construct a complete sample containing all the bursts localized by the WXM on-board HETE-2, which are selected with a uniform criterion and whose observed parameters can be constrained. We then derive the intrinsic E_peak, T_90 and E_iso distributions using their redshift when it is available, or their pseudo-redshift otherwise. We finally compute the number of GRB (N_Vmax) within the visibility volume (V_max) of each GRB, in order to derive a weight for each detected burst accounting both for the detection significance and the star formation history of the universe. Results: The unbiased distributions obtained clearly show the predominence of X-ray flashes (XRFs) in the global GRB population. We also derive the rate of local GRBs: R0^H2 > 11 Gpc-3 yr-1, which is intermediate between the local rate obtained by considering only the high-luminosity bursts (~1 Gpc-3 yr-1) and that obtained by including the low-luminosity bursts (>200 Gpc-3 yr-1).