The connection between metallicity and metal-line kinematics in (sub-)damped Lyα systems

Murphy, Michael T.; Curran, S. J.; Webb, John R.; Menager, H.; Zych, Berkeley J.

doi:10.1111/j.1365-2966.2007.11457.x

Cited by 54 publications

(77 citation statements)

References 76 publications

(114 reference statements)

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“…Note that the interpretation of broad high-ion components in DLAs and sub-DLAs as hot and collisionally ionized is different from the interpretation of the O vi components in the IGM at z > ∼ 2, which (generally) appear to be photoionized (Carswell et al 2002;Bergeron et al 2002;Levshakov et al 2003;Bergeron & Herbert-Fort 2005;Reimers et al 2006;Lopez et al 2007), though see Reimers et al (2001) and Simcoe et al (2002Simcoe et al ( , 2006. Ledoux et al (2006) have presented a [Z/H]-∆v Neut correlation in DLAs and sub-DLAs, and have interpreted it as implying an underlying mass-metallicity relation (see also Wolfe & Prochaska 1998;Ledoux et al 1998;Murphy et al 2007;Prochaska et al 2007a). In this interpretation, ∆v Neut traces motions due to gravity.…”

Section: Narrow and Broad Componentsmentioning

confidence: 97%

“…We are partly motivated by the recent work of Ledoux et al (2006), who reported a correlation between low-ion line width ∆v Neut and metallicity [Z/H] in a sample of 70 DLAs and sub-DLAs, covering over two orders of magnitude in metallicity (see also Wolfe & Prochaska 1998;Murphy et al 2007;Prochaska et al 2007a). Since the line widths of the neutral species are thought to be gravitationally-dominated, the broader lines may be tracing the more massive halos, and so the ∆v Neut -[Z/H] correlation has been interpreted as evidence for an underlying massmetallicity relation.…”

Section: Introductionmentioning

confidence: 99%

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C IV absorption in damped and sub-damped Lyman-α systems

Fox¹,

Ledoux

Petitjean

et al. 2007

A&A

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We present a study of C iv absorption in a sample of 63 damped Lyman-α (DLA) systems and 11 sub-DLAs in the redshift range 1.75 < z abs < 3.61, using a dataset of high-resolution (6.6 km s −1 FWHM), high signal-to-noise VLT/UVES spectra. The complex absorption line profiles show both narrow and broad C iv components, indicating the presence of both warm, photoionized and hot, collisionally ionized gas. We report new correlations between the metallicity (measured in the neutral-phase) and each of the C iv column density, the C iv total line width, and the maximum C iv velocity. We explore the effect on these correlations of the sub-DLAs, the proximate DLAs (defined as those within 5000 km s −1 of the quasar), the saturated absorbers, and the metal line used to measure the metallicity, and we find the correlations to be robust. There is no evidence for any difference between the measured properties of DLA C iv and sub-DLA C iv. In 25 DLAs and 4 sub-DLAs, covering 2.5 dex in [Z/H], we directly observe C iv moving above the escape speed, where v esc is derived from the total line width of the neutral gas profiles. These high-velocity C iv clouds, unbound from the central potential well, can be interpreted as highly ionized outflowing winds, which are predicted by numerical simulations of galaxy feedback. The distribution of C iv column density in DLAs and sub-DLAs is similar to the distribution in Lyman Break galaxies, where winds are directly observed, supporting the idea that supernova feedback creates the ionized gas in DLAs. The unbound C iv absorbers show a median mass flow rate of ∼22 (r/40 kpc) M yr −1 , where r is the characteristic C iv radius.Their kinetic energy fluxes are large enough that a star formation rate (SFR) of ∼2 M yr −1 is required to power them.

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Section: Narrow and Broad Componentsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

C IV absorption in damped and sub-damped Lyman-α systems

Fox¹,

Ledoux

Petitjean

et al. 2007

A&A

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“…While some authors present observations that suggest strong Mg ii absorbers originate primarily in galactic superwinds from low-mass galaxies (Prochter et al 2006;Bouché et al 2006;Murphy et al 2007), others show that Mg ii absorbing galaxies resemble typical field galaxies ( Zibetti et al 2005;Kacprzak et al 2007;Nestor et al 2007) and the covering fraction of Mg + ions is roughly 50% (Tripp & Bowen 2005). A particularly puzzling result is the anticorrelation between W r (2796) ( hereafter W r ) and the clustering amplitude by Bouché et al (2006, hereafter B06).…”

Section: à2mentioning

confidence: 99%

On The Halo Occupation of Dark Baryons

Tinker

Chen

2008

ApJ

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We introduce a new technique that adopts the halo occupation framework for understanding the origin of QSO absorption-line systems. Our initial study focuses specifically on Mg ii absorbers. We construct a model of the gaseous content in which the absorption equivalent width W r is determined by the amount of cold gas, in the form of discrete clouds, along a sight line through a halo. The two quantities that we specify per halo in the model are (1) the mean absorption strength per unit surface mass density A W (M ), and (2) the mean covering factor g (M ) of the gaseous clouds. These parameters determine the conditional probability distribution of W r as a function of halo mass, P(W r jM ). Two empirical measurements are applied to constrain the model: (1) the absorber frequency distribution function and (2) the W r -dependent clustering amplitude. We find that the data demand a rapid transition in the gas content of halos at $10 11.5 h À1 M , below which halos contain predominantly cold gas and beyond which gas becomes predominantly hot. In order to reproduce the observed overall strong clustering of the absorbers and the anticorrelation between W r and halo mass M, roughly 5% of gas in halos up to 10 14 h À1 M is required to be cold. The gas covering factor is near unity over a wide range of halo masses, supporting the idea that Mg ii systems probe an unbiased sample of typical galaxies. We discuss the implications of our study in the contexts of mass assembly of distant galaxies and the origin of QSO absorption-line systems.

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“…The probability of resolving these features can be increased by finding gas clouds with simple kinematics, which are more common at the lowest metallicity (Ledoux et al 2006;Murphy et al 2007;Prochaska et al 2008;Jorgenson et al 2013;Neeleman et al 2013;Cooke et al 2015); in general, the most metal-poor systems exhibit simple and quiescent kinematics. Given the low metallicity of the DLA toward J1358+0349, based on the ESI spectra, we acquired two high-quality, highresolution spectra of this quasar with the aim of measuring D/H.…”

Section: Observations and Data Reductionmentioning

confidence: 99%