Quasar Absorption-Line Systems and Astrobiology

Vladilo, G.

doi:10.1007/978-94-007-1003-0_35

Cited by 2 publications

(2 citation statements)

References 6 publications

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“…Overall, we conclude that the existing data do not suggest much evolution of the conventional dust content indicator, [Cr/Zn] in DLAs with redshift. Recently Vladilo (2004) has found evidence for an increase of dust-to-gas ratio with increasing metallicity, using [Fe/Zn] in 38 DLAs, but has found only a weak evidence for the evolution of this ratio with time.…”

Section: Redshift Evolution Of Dust Contentmentioning

confidence: 99%

Metals and Dust in Intermediate‐Redshift Damped Lyα Galaxies

Khare¹,

Kulkarni²,

Lauroesch³

et al. 2004

ApJ

136

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We report spectroscopic observations with the Multiple Mirror Telescope for 11 damped Lyman-alpha absorbers (DLAs) or strong DLA candidates at 0.1 < z < 1.5, including several absorbers discovered in the Sloan Digital Sky Survey. In particular, we have measured absorption lines of Zn II, Cr II, Ni II, Fe II, Mn II, Ti II, Ca II, and Si II. These measurements have doubled the sample of Zn and Cr measurements at z < 1. The average relative abundance patterns in these objects are very similar to those found for high-redshift DLAs reported in the literature. Our observations suggest that the dust content, as determined by [Cr/Zn], does not show much change with redshift. We also examine the sample for correlation of [Cr/Zn] with estimates of the quasar reddening. Our data suggest that the global mean metallicity of DLAs, as measured by the gas phase abundance of Zn, at best shows a weak evolution with redshift over the range 0.4 < z < 3.9.

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Section: Redshift Evolution Of Dust Contentmentioning

confidence: 99%

Metals and Dust in Intermediate‐Redshift Damped Lyα Galaxies

Khare¹,

Kulkarni²,

Lauroesch³

et al. 2004

ApJ

136

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“…Dust effects can be important if the extinction increases with metal column density as found in interstellar clouds (Vladilo et al 2006;Vladilo & Péroux 2005). Indeed, the dust content increases with metallicity (Vladilo 2004) and dust is expected to play a significant role at z < 1.5 if the metallicity increases with cosmic time. A way to find metal-rich absorbers minimising dust effects is to search for quasar absorbers with relatively low H i column density.…”

Section: Introductionmentioning

confidence: 99%

Metal abundances at z < 1.5: new measurements in sub-damped Lyman α absorbers

Péroux

Meiring

Kulkarni

et al. 2008

Monthly Notices RAS

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Damped Lyman α systems (DLAs) and sub‐DLAs seen towards background quasars provide the most detailed probes of elemental abundances. Somewhat paradoxically these measurements are more difficult at lower redshifts due to the atmospheric cut‐off, and so a few years ago our group began a program to study abundances at z < 1.5 in quasar absorbers. In this paper, we present new Ultraviolet and Visual Echelle Spectrograph (UVES) observations of six additional quasar absorption‐line systems at z < 1.5, five of which are sub‐DLAs. We find solar or above solar metallicity, as measured by the abundance of zinc, assumed not to be affected by dust, in two sub‐DLAs: one, towards Q0138−0005 with [Zn/H]=+0.28 ± 0.16; the other towards Q2335+1501 with [Zn/H]=+0.07 ± 0.34. Relatively high metallicity was observed in another system: Q0123−0058 with [Zn/H]=−0.45 ± 0.20. Only for the one DLA in our sample, in Q0449−1645, do we find a low metallicity, [Zn/H]=−0.96 ± 0.08. We also note that in some of these systems large relative abundance variations from component to component are observed in Si, Mn, Cr and Zn.

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Quasar Absorption-Line Systems and Astrobiology

Cited by 2 publications

References 6 publications

Metals and Dust in Intermediate‐Redshift Damped Lyα Galaxies

Metals and Dust in Intermediate‐Redshift Damped Lyα Galaxies

Metal abundances at z < 1.5: new measurements in sub-damped Lyman α absorbers

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