The high-redshift star formation rate derived from GRBs: possible origin and cosmic reionization

Understand

The collapsar model of long gamma-ray bursts (GRBs) indicates that they may trace the star formation history.

• So long GRBs may be a useful tool of measuring the high-redshift star formation rate (SFR).
• The collapsar model explains GRB formation via the collapse of a rapidly rotating massive star with $M> 30M_\odot$ into a black hole, which may imply a decrease of SFR at high redshift.
• However, we find that the \emph{Swift} GRBs during 2005-2012 are biased tracing the SFR, including a factor about $(1+z)^{0.5}$, which is in agreement with recent results.