2007/05/30 by Li-Xin Li, Li, Li-Xin
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.0705.4401
4 pages, including 4 figures. To appear in the proceedings of "070228: The Next Decade of GRB afterglows", Amsterdam, 19-23 March 2007
arxiv created 2007/05/30 · arxiv updated 2009/12/01
By dividing a sample of 48 long-duration gamma-ray bursts (GRBs) into four groups with redshift from low to high and fitting each group with the Amati relation log Eiso = a + b log Epeak, I find that parameters a and b vary with the mean redshift of the GRBs in each group systematically and significantly. The results suggest that GRBs evolve strongly with the cosmic redshift and hence are not standard candles.