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/

Zendy Plus

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

Zendy Tools

Zendy Open

GRB 090423 is the new high-z record holder of Gamma-ray bursts (GRBs) with z~8.2. We present a detailed analysis of both the spectral and temporal featuresof GRB 090423 observed with Swift/BAT and Fermi/GBM. We find that the T90observed with BAT in the 15-150 keV band is 13.2 s, corresponding to ~ 1.4 s atz=8.2. It once again gives rise to an issue whether the progenitors of high-zGRBs are massive stars or mergers since the discovery of GRB 080913 at z=6.7.In comparison with T90 distribution in the burst frame of currentredshift-known GRB sample, we find that it is marginally grouped into the longgroup (Type II GRBs). The spectrum observed with both BAT and GBM is wellfitted by a power-law with exponential cutoff, which yields an Ep=50.4+/-7.0keV. The event well satisfies the Amati-relation for the Type II GRBs withintheir 3 siggma uncertainty range. Our results indicate that this event would beproduced by the death of a massive star. Based on the Amati-relation, we deriveits distance modulus, which follows the Hubble diagram of the concordancecosmology model at a redshift of ~8.2.

GRB 090423: Marking the Death of a Massive Star at z=8.2