H iand OH absorption in the lensing galaxy of MG J0414+0534
We report the detection of H i21-cm absorption in the z= 0.96 early-type lensing galaxy towards MG J0414+0534 with the Green Bank Telescope. The absorption, with total NH i= 1.6 × 1018 (Ts/f) cm−2, is resolved into two strong components, probably due to the two strongest lens components, which are separated by 0.4 arcsec. Unlike the other three lenses that have been detected in H i, J0414+0534 does not exhibit strong OH absorption, giving an OH/H icolumn density ratio of NOH/NH i≲ 10−6 (for Ts= 100 K, Tx= 10 K and fH i=fOH= 1 ). This underabundance of molecular gas may indicate that the extreme optical–near-infrared colour (V−K= 10.26) along the line of sight is not due to the lens. We therefore suggest that despite the strong upper limits on molecular absorption at the quasar redshift, as traced by millimetre lines, the extinction occurs primarily in the quasar host galaxy.
Document Type: Research Article
Affiliations: 1: Centre for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309-0389, USA 2: CSIRO Australia Telescope National Facility, PO Box 76, Epping, NSW 1710, Australia 3: National Radio Astronomy Observatory, PO Box 2, Rt. 28/92 Green Bank, WV 24944-0002, USA 4: School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
Publication date: November 1, 2007