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.