Abstract / Description of output
Measuring rest-frame ultraviolet rotational transitions from the Lyman
and Werner bands in absorption against a bright background continuum is
one of the few ways to directly measure molecular hydrogen
(H2). Here, we report the detection of absorption from
H2 at z = 0.56 in a subdamped Lyα system with neutral
hydrogen column density NHI = 1019.5 ± 0.2
cm-2. This is the first H2 system analysed at a
redshift of
-1.93 ± 0.36 based on modelling the line profiles, with a robust
model-independent lower limit of fH2 >
10-3. This is higher than fH2 values
seen along sightlines with similar NHI through the Milky Way
disc and the Magellanic Clouds. The metallicity of the absorber is
0.19+0.21-0.10 solar, with a dust-to-gas ratio of
Original language | English |
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Pages (from-to) | 178-193 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 433 |
Issue number | 1 |
DOIs | |
Publication status | Published - 27 May 2013 |
Keywords / Materials (for Non-textual outputs)
- ISM: molecules
- galaxies: haloes
- quasars: absorption lines