J/A+A/611/A76 DLAS dust-corrected metallicity (De Cia+, 2018)
The cosmic evolution of dust-corrected metallicity in the neutral gas.
De Cia A., Ledoux C., Petitjean P., Savaglio S.
<Astron. Astrophys., 611, A76 (2018)>
=2018A&A...611A..76D 2018A&A...611A..76D (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Abundances ; Extinction ; Redshifts
Keywords: quasars: absorption lines - galaxies: abundances -
dust, extinction
Abstract:
Interpreting abundances of damped Ly-α absorbers (DLAs) from
absorption-line spectroscopy has typically been a challenge because of
the presence of dust. Nevertheless, because DLAs trace distant
gas-rich galaxies regardless of their luminosity, they provide an
attractive way of measuring the evolution of the metallicity of the
neutral gas with cosmic time. This has been done extensively so far,
but typically not taking proper dust corrections into account. The
aims of this paper are to: (i) provide a simplified way of calculating
dust corrections, based on a single observed [X/Fe], (ii) assess the
importance of dust corrections for DLA metallicities and their
evolution, and (iii) investigate the cosmic evolution of iron for a
large DLA sample. We have derived dust corrections based on the
observed [Zn/Fe], [Si/Fe], or [S/Fe], and confirmed their robustness.
We present dust-corrected metallicities in a scale of [Fe/H]tot for
236 DLAs over a broad range of z, and assess the extent of dust
corrections for different metals at different metallicities. Dust
corrections in DLAs are important even for Zn (typically of 0.1-0.2,
and up to 0.5dex), which is often neglected. Finally, we study the
evolution of the dust-corrected metallicity with z. The DLA
metallicities decrease with redshift, by a factor of 50-100 from
today to ∼12.6 billion years ago (z=5). When including dust
corrections, the average DLA metallicities are 0.4-0.5dex higher
than without corrections. The upper envelope of the relation between
metallicity and z reaches solar metallicity at z≲0.5, although
some systems can have solar metallicity already out to z∼3.
Description:
We developed a simplified method for calculating dust corrections to
metal abundances (which we called the single-reference method), and
confirmed the robustness of this method by comparing the dust
corrections to the solid ones derived in Paper I (De Cia et al.,
2016A&A...596A..97D 2016A&A...596A..97D) by studying several metals simultaneously. We
applied the new dust corrections to two DLA samples with published
abundances: (i) a selection of high-quality measurements (the clean
sample), and (ii) the largest number of available measurements (the
large sample).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablec1.dat 87 24 *Dust-corrected metallicities and depletions for
the clean sample
tablec2.dat 85 236 *Dust-corrected metallicities and depletions for
the large sample
--------------------------------------------------------------------------------
Note on tablec1.dat and tablec2.dat: Additional metallicities and depletions
from the DLA sample of Ledoux et al. (2006ApJ...640L..25L 2006ApJ...640L..25L) are already
reported in Paper I (De Cia et al., 2016A&A...596A..97D 2016A&A...596A..97D).
--------------------------------------------------------------------------------
See also:
J/ApJ/755/89 : Metallicities of damped Lyα systems (Rafelski+, 2012)
J/MNRAS/452/4326 : Metal-rich damped Lyα systems at z∼2 (Berg+, 2015)
J/A+A/606/A13 : QSO eHAQ0111+0641 spectra (Fynbo+, 2017)
Byte-by-byte Description of file: tablec1.dat tablec2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Name
17- 21 F5.3 --- z Redshift
23- 27 F5.2 [cm-2] logN(HI) HI column density
29- 32 F4.2 [cm-2] e_logN(HI) rms uncertainty on N(HI)
33- 34 A2 --- Note [aa] Not eon N(HI) (1)
36- 40 F5.2 [-] [Fe/H]tot Dust-corrected metallicity
42- 45 F4.2 [-] e_[Fe/H]tot rms uncertainty on [Fe/H]tot
47- 51 F5.2 [-] [Zn/Fe]exp Expected [Zn/Fe] abundance
53- 57 F5.2 --- dZn Depletion of Zn
59- 63 F5.2 --- dSi Depletion of Si
65- 69 F5.2 --- dFe Depletion of Fe
71- 75 F5.2 --- d[X/Fe] Dust-corrected [X/Fe] abundance
77- 80 F4.2 --- e_d[X/Fe] rms uncertainty on d[X/Fe]
82- 83 A2 --- X Element of [X/Fe] abundance
85- 87 A3 --- Ref References (2)
--------------------------------------------------------------------------------
Note (1): aa: The sum of N(HI) and 2 N(H2) for this strong molecular system.
Note (2): References as follows:
a = Ellison et al. (2012MNRAS.424..293E 2012MNRAS.424..293E)
b = Peroux et al. (2006MNRAS.372..369P 2006MNRAS.372..369P)
c = Pettini et al. (2000ApJ...532...65P 2000ApJ...532...65P)
d = Peroux et al. (2008MNRAS.386.2209P 2008MNRAS.386.2209P)
e = Rao et al. (2005AJ....129....9R 2005AJ....129....9R)
f = Meiring et al. (2011ApJ...732...35M 2011ApJ...732...35M)
g = Pettini et al. (1999ApJ...510..576P 1999ApJ...510..576P)
h = Moller et al. (2013MNRAS.430.2680M 2013MNRAS.430.2680M)
i = Rafelski et al. (2012, Cat. J/ApJ/755/89)
j = Ma et al. (2015MNRAS.454.1751M 2015MNRAS.454.1751M)
k = Fynbo et al. (2017, Cat. J/A+A/606/A13)
l = Noterdaeme et al. (2017A&A...597A..82N 2017A&A...597A..82N)
m = Noterdaeme et al. (2010A&A...523A..80N 2010A&A...523A..80N)
n = Poudel et al. (2018MNRAS.473.3559P 2018MNRAS.473.3559P)
o = Berg et al. (2015, Cat. J/MNRAS/452/4326) and references therein
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
De Cia et al., Paper I 2016A&A...596A..97D 2016A&A...596A..97D
(End) Patricia Vannier [CDS] 31-May-2018