English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Because of the limit in the number of gamma‐ray bursts (GRBs) with available redshifts and spectra, all current investigations on the correlation among GRB variables use burst samples with redshifts that span a very large range. Evolution and selection effects have thus been ignored, which might have an important influence on the results. In this Letter, we divide the 48 long‐duration GRBs studied by Amati into four groups with redshift from low to high, each group containing 12 GRBs. Then we fit each group with the Amati relation log  E  iso = a + b  log  E  peak , and check whether the parameters  a  and  b  evolve with the GRB redshift. We find that  a  and  b  vary with the mean redshift of the GRBs in each group systematically and significantly. Monte Carlo simulations show that there is only a ∼4 per cent chance that the variation is caused by the selection effect arising from the fluence limit. Hence our results may indicate that GRBs evolve strongly with cosmological redshift.

Variation of the Amati relation with cosmological redshift: a selection effect or an evolution effect?