First Detection of Hydrogen 21-cm Emission
in a Galaxy at Cosmological Distance.
Martin Zwaan, Peter van Dokkum, Marc Verheijen
The purple contours show the distribution of the neutral hydrogen
This gas has been detected in our deep survey with the
Synthesis Radio Telescope and is at a distance of approximately three
billion light-years. The underlying colour image shows that the hydrogen
gas coincides with a spiral galaxy in the outskirts of galaxy cluster Abell
2218. One of the galaxy's spiral arms seems to be connected with a
smaller companion galaxy.
(Optical image taken with the Keck
Telescope on Hawaii.)
This Hubble Space Telescope image shows the center of cluster Abell
here for a larger version.) Our detection of neutral hydrogen is
approximately 6 million light years to the west of this dense centre.
(picture credit: Hubble Space Telescope, NASA)
The paper will be published in the 7 September edition of Science.