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

In this work, the time-resolved BAT/GBM/LAT joint spectral analysis ofGRB110731A during the prompt phase from the GBM trigger and up to 13 secondslater showed that, at the very early phase of prompt emission, the emissionmechanism is closest to the standard fireball model. This model over-predictsthe thermal photospheric emission and used to contradict observations.Lightcurves at different energy bands revealed two distinguishable phases thatmay come from different regions. First, we have an early phase, which is notdetected by LAT, and is dominated by lower energies, which arises from thephotospheric emissions without any emissions involved in dissipation mechanismsand characterized by low Lorentz factor and high radiation efficiency. This isfollowed by a later phase, having a more complex structure that remarkablyfollows the same track in all energy bands and is attributed to emissions frominternal shocks. This burst is a good candidate to study both thermal andnon-thermal emissions, since the two phases can be clearly separated inlightcurve and spectrum. The rapid variation of Lorentz factor and the valuesof photospheric radii, which are relatively far away from the central engine inPhase 2, are more consistent with the mechanism of collisional heating inbaryonic jets. Further information can be obtained by combining morewavelengths with the help of the other detectors.

Two distinct phases in the first 13 seconds of GRB110731A prompt emission