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

GRB050904 is the gamma-ray burst with the highest measured redshift. Weperformed time resolved X-ray spectroscopy of the late GRB and early afterglowemission. We find robust evidence for a decrease with time of the soft X-rayabsorbing column. We model the evolution of the column density due to the flashionization of the GRB and early afterglow photons. This allows us to constrainthe metallicity and geometry of the absorbing cloud. We conclude that theprogenitor of GRB050904 was a massive star embedded in a dense metal enrichedmolecular cloud with Z~0.03 Z_solar. This is the first local measurement ofmetallicity in the close environment of a GRB and one of the highest redshiftmetallicity measurements. We also find that the dust associated with the cloudcannot be similar to that of our Galaxy but must be either sizably depleted ordominated by silicate grains. We discuss the implications of these results forGRB progenitors and high redshift star formation.Comment: 4 pages, 2 figures. Accepted for publication on Astrophysical Journal  Letter

A Metal-rich Molecular Cloud Surrounds GRB 050904 at Redshift 6.3