Redshift-dependent lag-luminosity relation in 565 BATSE gamma-ray bursts

We compared redshifts z(Y) measured from the Yonetoku relation and z(lag) from the lag luminosity relation for 565 BATSE gamma-ray bursts ( GRBs) and were surprised to find that the correlation between these two redshifts is very low. Assuming that the luminosity is a function of both zY and the intrinsic spectral lag tau(lag), we found a new redshift-dependent lag-luminosity relation L= 7.5 x 10(50) erg s(-1) ( 1+ z) (2.53)tau(- 0.282)(lag) with the correlation coefficient of 0.77 and the chance probability of 7.9 x 10(-75). Although the spectral lag is computed from two channels of the Burst and Transient Source Experiment ( BATSE), our new lag - luminosity relation suggests that a future lag - luminosity relation defined in the Swift data should also depend on the redshift.