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

We present multiwavelength observations of the gamma-ray burst GRB 051028detected by HETE-2 in order to derive its afterglow emission parameters and todetermine the reason for its optical faintness when compared to other events.Observations were taken in the optical (2.0m Himalayan Chandra Telescope, 1.34mTautenburg, 4.2m William Herschel Telescope) and in X-rays (Swift/XRT) between2.7 hours and 10 days after the onset of the event. The data can be interpretedby collimated emission in a jet with a typical value of $p$ = 2.4 which ismoving in an homogeneous interstellar medium and with a cooling frequencynu_{c} still above the X-rays at 0.5 days after the burst onset. GRB 051028 canbe classified as a ``gray'' or ``potentially dark'' GRB. On the basis of thecombined optical and Swift/XRT data, we conclude that the reason for theoptical dimness is not extra absorption in the host galaxy, but rather the GRBtaking place at high-redshift.We also notice the very striking similarity withthe optical lightcurve of GRB 050730, a burst with a spectroscopic redshift of3.967, although GRB 051028 is about 3 mag fainter. We suggest that the bumpcould be explained by multiple energy injection episodes and that the burst isintrinsically faint when compared to the average afterglows detected since1997. The non-detection of the host galaxy down to R = 25.1 is also consistentwith the burst arising at high redshift, compatible with the published pseudo-zof 3.7 +/- 1.8.Comment: 5 pages, 7 figures. Accepted in Astronomy and Astrophysic

GRB 051028: an intrinsically faint gamma-ray burst at high redshift?