The ESO UVES advanced data products quasar sample: II. Cosmological evolution of the neutral gas mass density

By T. Zafar, C. Péroux, A. Popping, Bruno Milliard, J. Deharveng, S. Lam, Icrar, O. University. 2013

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Quasar foreground damped absorbers, associated with HI-rich galaxies allow to estimate the neutral gas mass over cosmic time, which is a possible indicator of gas consumption as star formation proceeds. The DLAs and sub-DLAs are believed to contain a large fraction of neutral gas mass in the Universe. In Paper I of the series, we present the results of a search for DLAs and sub-DLAs in the ESO-UVES Advanced Data Products dataset of 250 quasars. Here we use an unbiased sub-sample of sub-DLAs from this dataset. We build a subset of 122 quasars ranging from 1.5 <z_em < 5.0, suitable for statistical analysis. The statistical sample is analyzed in conjunction with other sub-DLA samples from the literature. This makes up a combined sample of 89 sub-DLAs over a redshift path of $\Delta z=193$. Redshift evolution of the number density and the line density are derived for sub-DLAs and compared with the LLSs and DLAs measurements from the literature. The results indicate that these three classes of absorbers are evolving in the redshift interval 1 < z < 5. The column density distribution, f(N,z), down to the sub-DLA limit is determined. The flattening of f_(N,z) in the sub-DLA regime is present in the observations. The redshift evolution of f_(N,z) down to sub-DLA regime is also presented, indicating the presence of more sub-DLAs at high-redshift as compared to low-redshift. f_(N,z) is further used to determine the neutral gas mass density, Omega_g, at 1.5 < z < 5.0. The complete sample shows that sub-DLAs contribute 8-20% to the total Omega_g from 1.5 < z < 5.0. In agreement with previous studies, no evolution of Omega_g is seen from low-redshift to high-redshift, suggesting that star formation solely cannot explain this non-evolution and replenishment of gas and/or recombination of ionized gas is needed. (Abridged)

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d25b83d00f425899441fe162dc6a630d4c82c772

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Citations in the corpus

Evolution of the atomic and molecular gas content of galaxies (2013, methodology): “…& Rawlings 2009b; Martin et al. 2010; Braun 2012) and high-z estimates of the HI density obtained from Damped Lyman-α (DLA) absorption systems (e.g., Péroux et al. 2005; Rao, Turnshek & Nestor 2006; Guimarães et al. 2009; Prochaska & Wolfe 2009; Noterdaeme et al. 2012; Zafar et al. 2013).”
Ingredients for 21 cm Intensity Mapping (2018, result): “We find excellent agreement with the observations, which are shown as black points with errorbars, at redshifts [1.8-3.5] (Péroux et al. 2005), [2.0-3.5] (Noterdaeme et al. 2012), [3.5- 5.4] (Crighton et al. 2015) and [1.5-5.0] (Zafar et al. 2013).”
The Neutral Hydrogen Cosmological Mass Density at z = 5 (2015, background): “…neutral gas at 2 < z < 5 is in DLAs, with a ∼ 15% contribution from sub-damped Lyα systems (which have 1019 < NHI/(cm −2) < 1020.3) and more highly ionized Lyman limit and Lyα forest absorbers with NHI < 1019cm−2 (Péroux et al. 2005; Prochaska et al. 2005; O’Meara et al. 2007; Zafar et al. 2013).”
Star formation sustained by gas accretion (2014, background): “From ESO UVES spectra of 122 QSOs and data from the literature, Zafar et al. (2013) find a constant neutral gas mass density in the universe for 0.1 < z < 5, even though star formation varies significantly during that period (Fig.”