Kanekar, N. ; Briggs, F. H. (2003) HI absorption in a gravitational lens at z ~ 0.7645 Astronomy & Astrophysics, 412 (2). L29-L32. ISSN 0004-6361
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Official URL: http://doi.org/10.1051/0004-6361:20031676
Related URL: http://dx.doi.org/10.1051/0004-6361:20031676
Abstract
We have used the Westerbork Synthesis Radio Telescope to detect HI 21 cm absorption at $z \sim 0.7645$ in the gravitational lens system towards PMN J0134-0931. The 21 cm profile has two broad components, with peak optical depths of $0.047 \pm 0.007$ and $0.039 \pm 0.007$, at heliocentric redshifts $0.76470 \pm 0.00006$ and $0.76348 \pm 0.00006$, 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 $\sim $500 km s-1 (between nulls) and an equivalent width of $7.1 \pm 0.08$ km s-1. This would imply a total HI column density of $2.6 \pm 0.3 \times 10^{21}$ 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.
Item Type: | Article |
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Source: | Copyright of this article belongs to The European Southern Observatory. |
Keywords: | Galaxies: Individual: Pmn J0134-0931; Gravitational Lensing; Radio Line; ISM. |
ID Code: | 118123 |
Deposited On: | 14 May 2021 06:57 |
Last Modified: | 14 May 2021 06:57 |
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