GRB 090423 at redshift 8 - the most distant object we know to date

GRB 090423 at a redshift of about 8 is by far the most distant gamma-ray burst seen to date, and also the most distant object of the Universe we know so far. As such, its discovery is an important event for astrophysics and cosmology.

Pending an accurate determination of the redshift (8.0 or 8.2 or anything similar), the following rough numbers apply:
   look-back time: 13 Gyr
   age of the Universe: 600 Myr (4.5% of 13.66 Billion years)
   luminosity distance: 85 Gpc

Since some years, Gamma-ray bursts were believed (at least within the GRB community) to be ideal probes for the early Universe. The discovery of GRB 090423 is a wonderful confirmation of this believe. The quick succession of two record-breaking GRBs (the previous record holder was GRB 080913, Greiner et al. 2009, ApJ 693, 1610) implies that present-day routine follow-up strategies are now adequate to not miss high-redshift afterglows, and let us hope that even more distant GRBs will be identified to allow us to study the era of the formation of the first stars.

Details on GRB 090423

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Jochen Greiner [Disclaimer]
Last modified: Fri Oct 30 17:42:49 MET 2009