GCN Circular 5004
A. Pelangeon & J-L. Atteia (LATT-OMP) report: A "Pseudo-redshift Calculator" for *long Gamma-Ray Bursts* is now available at this address: http://www.ast.obs-mip.fr/grb/pz This calculator computes redshift-estimates using the redshift indicator described in Pelangeon et al. (astro-ph/0601150), which is an improvement of the first version proposed by Atteia (A&A, 407, L1-L4, 2003). This version is based on the spectral parameters of the prompt emission measured during the most intense part of the burst. In this web site you will find: - Explanations on the redshift indicator, and directions to follow in order to compute valuable pseudo-redshifts. - An interactive program to compute pseudo-redshifts. This program requires the measure of the GRB spectral parameters, especially alpha, Epeak and the fluence. - A catalog of pseudo-redshifts for recent GRBs. We provide this tool as a service to the community. Pseudo-redshifts may constitute a useful piece of information to establish the follow-up strategy of newly detected GRBs with known spectral parameters.