Abstract
We present Hubble Space Telescope and ground-based data on the zabs = 0.8596 metal-line absorption system along the line of sight to PKS 0454+0356. The system is a moderate-redshift damped Lyα system, with N(H I) = (5.7 ± 0.3) × 1020 cm-2 as measured from the faint Object Spectrograph spectrum. We also present ground-based images which we use to identify the galaxy which most probably gives rise to the damped system; the most likely candidate is relatively underluminous by QSO absorber standards (MB ∼ - 19.0 for q0 = 0.5 and H0 = 50 km s-1 Mpc-1) and lies ∼8.5 h-1 kpc in projection from the QSO sight line. Ground-based measurements of Zn II, Cr II, and Fe II absorption lines from this system allow us to infer abundances of [Zn/H] = -1.1, [Cr/H] = -1.2, and [Fe/H] = -1.2, indicating overall metallicity similar to damped systems at z > 2, and that the depletion of Cr and Fe onto dust grains may be even less important than in many of the high-redshift systems of comparable metallicity. Limits previously placed on the 21 cm optical depth in the z = 0.8596 system, together with our new N(H I) measurement, suggest a very high spin temperature for the H I, Ts > 580 K.
Original language | English (US) |
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Pages (from-to) | L45-L48 |
Journal | Astrophysical Journal |
Volume | 440 |
Issue number | 2 PART 2 |
DOIs | |
State | Published - Feb 20 1995 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
Keywords
- Galaxies: distances and redshifts
- Galaxies: evolution
- Quasars: absorption lines