The Metallicity of High‐Redshift Galaxies: The Abundance of Zinc in 34 Damped Lyα Systems from<i>z</i>= 0.7 to 3.4

Pettini, Max; Smith, L. J.; King, David L.; Hunstead, R. W.

doi:10.1086/304564

Cited by 313 publications

(420 citation statements)

References 65 publications

(104 reference statements)

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“…The observed distribution of [Zn/H] measurements peaks at [Zn/H] −1.1 dex and does not show systems below ≈−2 dex or above solar metallicity (Pettini et al 1997). Although this distribution is likely biased at both ends, we do expect a genuine decline in the number of DLAs below and above some critical values of metallicity.…”

Section: The Shape Of the True Metallicity Distributionmentioning

confidence: 67%

The dust obscuration bias in damped Lyman αsystems

Vladilo

Péroux

2005

A&A

141

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We present a new study of the effects of quasar obscuration on the statistics of Damped Ly α (DLA) systems. We show that the extinction of any Galactic or extragalactic H i region, A λ , increases linearly with the column density of zinc, with a turning point ∂A λ /∂(log N Zn ) = 1, above which background sources are suddenly obscured. We derive a relation A λ = A λ (N H , Z, z) between the extinction of a DLA system and its H i column density, N H , metallicity, Z, fraction of iron in dust, f Fe (Z), and redshift, z. From this relation we estimate the fraction of DLA systems missed as a consequence of their own extinction in magnitude-limited surveys. We derive a method for recovering the true frequency distributions of N H and Z in DLAs, f N H and f Z , using the biased distributions measured in the redshift range where the observations have sufficient statistics (1.8 ≤ z ≤ 3). By applying our method we find that the well-known empirical thresholds of DLA column densities, N Zn < ∼ 10 13.1 atoms cm −2 and N H i < ∼ 10 22 atoms cm −2 , can be successfully explained in terms of the obscuration effect without tuning of the local dust parameters. The obscuration has a modest effect on the distribution of quasar apparent magnitudes, but plays an important role in shaping the statistical distributions of DLAs. The exact estimate of the bias is still limited by the paucity of the data ( 40 zinc measurements at 1.8 ≤ z ≤ 3). We find that the fraction of DLAs missed as a consequence of obscuration is ∼30% to 50%, consistent with the results of surveys of radio-selected quasars. By modelling the metallicity distribution with a Schechter function we find that the mean metallicity can be ∼5 to 6 times higher than the value commonly reported for DLAs at z ∼ 2.3.

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Section: The Shape Of the True Metallicity Distributionmentioning

confidence: 67%

The dust obscuration bias in damped Lyman αsystems

Vladilo

Péroux

2005

A&A

141

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“…Elements classified as volatiles and refractories according to condensation calculations (Lodders 2003) are characterized by low and high levels of depletion, respectively (Savage & Sembach 1996). Dust depletion in DLAs is known to be moderate, similar to that found in low-density components of the Galactic ISM (Pettini et al 1994(Pettini et al , 1997Ledoux et al 2002;Vladilo et al 2011). For this reason, depletions of well-known volatile elements, such as zinc or sulphur, or even moderately refractory elements, such as silicon, have negligible or modest effects on DLA abundance measurements.…”

Section: Dust Depletionmentioning

confidence: 94%

The ESO UVES Advanced Data Products Quasar Sample – IV. On the deficiency of argon in DLA systems

Zafar¹,

Vladilo²,

Péroux³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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In this work, we study argon abundances in the interstellar medium of high-redshift galaxies (2.0 z abs 4.2) detected as Damped Lyα absorbers (DLA) in the spectra of background quasars. We use high-resolution quasar spectra obtained from the ESO-UVES advanced data products (EUADP) database. We present 3 new measurements and 5 upper limits of Ar i. We further compiled DLAs/sub-DLA data from the literature with measurements available of argon and α-capture elements (S or Si), making up a total of 37 systems, i.e. the largest DLA argon sample investigated so far. We confirm that argon is generally deficient in DLAs, with a mean value [Ar/α] ≃ −0.4 ± 0.06 dex (standard error of the mean). The [Ar/α] ratios show a weak, positive trend with increasing H i column density and increasing absorption redshift, and a weak, negative trend with dust-free metallicity, [S/H]. Detailed analysis of the abundance ratios indicates that Ar i ionisation, rather than dust depletion or nucleosynthetic evolution, is responsible for the argon deficiency. Altogether, the observational evidence is consistent with a scenario of argon ionisation dominated by quasar metagalactic radiation modulated by local H i self-shielding inside the DLA host galaxies. Our measurements and limits of argon abundances suggest that the cosmic reionisation of He ii is completed above z ∼ 3, but more measurements at z abs > 3.5 are required to probe the final stages of this process of cosmic reionisation.

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“…should account for the discrepancy between theory (solid line) and observations (data from [11]) b) Evolution of gas and stars; data for HI gas density from [29]. c) The evolution of Zn/H in various regions of spiral disks (only three are shown here, corresponding to those on the left) brackets well the observed abundances of Zn/H in Lyo absorbers (data from [18,15]); those systems may well be (proto)galactic disks. d) The corresponding evolution of D shows that considerable depletion may take place in the inner disk regions, but only at low redshifts; abundances measured at high redshifts should be close to the primordial value.…”

Section: Implications For "Cosl\tiic Chemical Evolution"mentioning

confidence: 63%

“…These observations concern: i) the "global" SFR ( [11]); ii) the HI content of the Universe ( [29]) and iii) the abundances of various elements in gaseous systems, in the line of sight of quasars ( [15,18]). To these one should include observations of D abundances, although the current status of those observations does not allow to establish a trend as a function of redshift.…”

Section: Implications For "Cosl\tiic Chemical Evolution"mentioning

confidence: 99%

The Chemical Evolution of Light Elements in Our Galaxy

Prantzos

2002

Symp. - Int. Astron. Union

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Progress in the theory of galactic chemical evolution has been very slow and it is only in the solar neighborhood that observations constrain seriously the parameters of the various models. The history revealed on the basis of these data allows only for a small depletion of deuterium (D), less than a factor of 3 from its pregalactic value (Sec. 2.1). The observational data for the rest of the Milky Way disk are much less constraining for the models. They suggest, however, that a much larger astration (and, hence, D depletion) has taken place in the inner Galaxy; the resulting D gradient, measurable by the future FUSE-LYMAN mission, should provide invaluable information as to the past history of the disk (Sec. 2.2). Also, assuming that our Galaxy is a typical spiral, one can calculate the properties of disk galaxies as a function of redshift (in the framework of a given cosmological model) and compare to the observed properties of the extragalactic universe: global star formation rate, gas content and metal abundances in gas clouds. It turns out that D can be considerably depleted in galaxy disks, but only at low redshifts (Sec. 2.3).

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The Metallicity of High‐Redshift Galaxies: The Abundance of Zinc in 34 Damped Lyα Systems fromz= 0.7 to 3.4

Cited by 313 publications

References 65 publications

The dust obscuration bias in damped Lyman αsystems

The dust obscuration bias in damped Lyman αsystems

The ESO UVES Advanced Data Products Quasar Sample – IV. On the deficiency of argon in DLA systems

The Chemical Evolution of Light Elements in Our Galaxy

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