2003/11/03 by Nissim Kanekar, N. Kanekar, F. H. Briggs · 2 citations
Physics and Astronomy · #Galaxies: Formation, Evolution, Phenomena #Pulsars and Gravitational Waves Research #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1051/0004-6361:20031676
published as Astron.Astrophys. 412 (2003) L29 · 4 pages, 4 figures. Accepted for publication in A&A Letters
arxiv created 2003/11/03 · openalex publication_date 2003/11/28 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/08/01
We have used the Westerbork Synthesis Radio Telescope to detect HI 21 cm absorption at in the gravitational lens system towards PMN J0134-0931. The 21 cm profile has two broad components, with peak optical depths of and , at heliocentric redshifts and , respectively. The redshift of the stronger component matches that of CaII H and K absorption detected earlier. The absorption has a total velocity width of ~500 km s-1 (between nulls) and an equivalent width of km s-1. This would imply a total HI column density of cm-2, for a spin temperature of 200 K and a covering factor of unity. The high estimated HI column density is consistent with the presence of large amounts of dust at the lens redshift; the intervening dust could be responsible for the extremely red colour of the background quasar.