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

GRB 090426 is a short‐duration burst detected by  Swift  ( s in the observer frame and  s in the burst frame at   z = 2.609 ). Its host galaxy properties and some gamma‐ray‐related correlations are analogous to those seen in long‐duration gamma‐ray bursts (GRBs), which are believed to be of a massive star origin (so‐called Type II GRBs). We present the results of its early optical observations with the 0.8‐m Tsinghua University–National Astronomical Observatory of China Telescope (TNT) at Xinglong Observatory and the 1‐m LOAO telescope at Mt Lemmon Optical Astronomy Observatory in Arizona. Our well‐sampled optical afterglow light curve covers from  to 10 4  s after the GRB trigger. It shows two shallow decay episodes that are likely due to energy injection, which end at  and 7100 s, respectively. The decay slopes after the injection phases are consistent with each other (). The X‐ray afterglow light curve appears to trace the optical, although the second energy‐injection phase was missed due to visibility constraints introduced by the  Swift  orbit. The X‐ray spectral index is  without temporal evolution. Its decay slope is consistent with the prediction of the forward shock model. Both X‐ray and optical emission are consistent with being in the same spectral regime above the cooling frequency (). The fact that  is below the optical band from the very early epoch of the observation provides a constraint on the burst environment, which is similar to that seen in classical long‐duration GRBs. We therefore suggest that death of a massive star is the possible progenitor of this short burst.

Probing the nature of high‐ z short GRB 090426 with its early optical and X‐ray afterglows