Gas Accretion via Lyman Limit Systems

Lehner, N.

doi:10.1007/978-3-319-52512-9_6

Cited by 10 publications

(4 citation statements)

References 123 publications

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“…This low metallicity is among the most metal-poor LLS at z < 1 (e.g., Wotta et al 2016) and suggests that the absorber originates in inflows of pristine IGM into the LRG halo (e.g., Hafen et al 2017). The detection of a chemically-pristine Lyman limit absorber at z = 0.33 also shows that intergalactic medium at z < 1 may not be as chemically-enriched as previously thought (e.g., Shull et al 2014;Lehner 2017).…”

Section: Incidence Of Heavy Ions Around Lrgsmentioning

confidence: 78%

Characterizing circumgalactic gas around massive ellipticals at z ∼ 0.4 – I. Initial results★

Chen

Zahedy

Johnson

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present a new Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) absorption-line survey to study halo gas around 16 luminous red galaxies (LRGs) at z = 0.21 − 0.55. The LRGs are selected uniformly with stellar mass M star > 10 11 M and no prior knowledge of the presence/absence of any absorption features. Based on observations of the full Lyman series, we obtain accurate measurements of neutral hydrogen column density N (H I) and find that high-N (H I) gas is common in these massive quiescent halos with a median of log N (H I) = 16.6 at projected distances d < ∼ 160 kpc. We measure a mean covering fraction of optically-thick gas with log N (H I) > ∼ 17.2 of κ LLS = 0.44 +0.12 −0.11 at d < ∼ 160 kpc and κ LLS = 0.71 +0.11 −0.20 at d < ∼ 100 kpc. The line-of-sight velocity separations between the H I absorbing gas and LRGs are characterized by a mean and dispersion of v gas−gal = 29 km s −1 and σ v gas−gal = 171 km s −1 . Combining COS far-ultraviolet and ground-based echelle spectra provides an expanded spectral coverage for multiple ionic transitions, from low-ionization Mg II and Si II, to intermediate ionization Si III and C III, and to highionization O VI absorption lines. We find that intermediate ions probed by C III and Si III are the most prominent UV metal lines in LRG halos with a mean covering fraction of κ(C III) 0.1 = 0.75 +0.08 −0.13 for W r (977) 0.1Å at d < 160 kpc, comparable to what is seen for C III in L * and sub-L * star-forming and red galaxies but exceeding Mg II or O VI in quiescent halos. The COS-LRG survey shows that massive quiescent halos contain widespread chemically-enriched cool gas and that little distinction between LRG and star-forming halos is found in their H I and C III content.

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Section: Incidence Of Heavy Ions Around Lrgsmentioning

confidence: 78%

Characterizing circumgalactic gas around massive ellipticals at z ∼ 0.4 – I. Initial results★

Chen

Zahedy

Johnson

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…The KODIAQ survey shows that for H I-selected absorbers at z 2-3.5 with  N log 16 (Burns 2014;Lehner et al 2014; N. Lehner et al 2016, in preparation;Lehner 2017; see also Figure O VI -km s 1 . The breadth and strength of the O VI absorption in strong H I absorbers atz 2-3.5 are quite similar to those observed in starburst galaxies at low redshift (see, e.g., Grimes et al 2009;Tripp et al 2011;Muzahid et al 2015) Simcoe et al 2002;Muzahid et al 2012).…”

Section: O VI Associated With Pllss and Llssmentioning

confidence: 99%

“…The KODIAQ survey shows that for H I-selected absorbers at z ∼ 2-3.5 with log N HI 16, the O VI absorption has typically total column densities 14.2 log N OVI 15.5 and full-widths 150 ∆v OVI 500 km s −1 (Lehner et al 2014;Burns 2014;Lehner 2017; N. Lehner, J.C. Howk, J. O'Meara al. 2016, in prep., and see also Fig.…”

Section: O VI Associated With Pllss and Llssmentioning

confidence: 99%

The Cosmic Evolution of the Metallicity Distribution of Ionized Gas Traced by Lyman Limit Systems

Lehner

O’Meara

Howk

et al. 2016

ApJ

Self Cite

192

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(2016) 'The cosmic evolution of the metallicity distribution of ionized gas traced by Lyman limit systems.', Astrophysical journal., Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ), which are probed of the interface regions between the intergalactic medium (IGM) and galaxies. We study 31 H Iselected pLLSs and LLSs at < < z 2.3 3.3 observed with Keck/HIRES in absorption against background QSOs. We compare the column densities of metal ions to H I and use photoionization models to assess the metallicity. The metallicity distribution of the pLLSs/LLSs at < < z 2.3 3.3 is consistent with a unimodal distribution peaking atThe metallicity distribution of these absorbers therefore evolves markedly with z since at  z 1 it is bimodal with peaks atThere is a substantial fraction (25%-41%) of pLLSs/LLSs with metallicities well below those of damped Lyα absorbers (DLAs) at any studied z from  z 1 toz 2-4, implying reservoirs of metal-poor, cool, dense gas in the IGM/galaxy interface at all z. However, the gas probed by pLLSs and LLSs is rarely pristine, with a fraction of 3%-18% for pLLSs/LLSs withWe find C/α enhancement in several pLLSs and LLSs in the metallicity range, where C/α is 2-5 times larger than observed in Galactic metal-poor stars or high-redshift DLAs at similar metallicities. This is likely caused by preferential ejection of carbon from metal-poor galaxies into their surroundings.

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“…These observations provide us with clues as to (i) how galaxies balance external gas accretion (e.g., Lehner 2017;Rubin 2017) with turbulent outflows of material from supernovae (e.g., Hummels & Bryan 2012;Fielding et al 2017) and supermassive black holes (e.g., Johnson et al 2015;Kacprzak et al 2015); (ii) what is happening in the vast volume of "empty" space between galaxies (e.g., Peeples et al 2014);and (iii) what the CGM/IGM can tell us about the evolution of the universe as a whole (e.g.,…”

Section: Why Observe Simulated Data?mentioning

confidence: 99%

Trident: A Universal Tool for Generating Synthetic Absorption Spectra from Astrophysical Simulations

Hummels

Smith

Silvia

2017

ApJ

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Hydrodynamical simulations are increasingly able to accurately model physical systems on stellar, galactic, and cosmological scales; however, the utility of these simulations is often limited by our ability to directly compare them with the data sets produced by observers: spectra, photometry, etc. To address this problem, we have created TRIDENT, a Python-based open-source tool for post-processing hydrodynamical simulations to produce synthetic absorption spectra and related data. TRIDENT can (i) create absorption-line spectra for any trajectory through a simulated data set mimicking both background quasar and down-the-barrel configurations; (ii) reproduce the spectral characteristics of common instruments like the Cosmic Origins Spectrograph; (iii) operate across the ultraviolet, optical, and infrared using customizable absorption-line lists; (iv) trace simulated physical structures directly to spectral features; (v) approximate the presence of ion species absent from the simulation outputs; (vi) generate column density maps for any ion; and (vii) provide support for all major astrophysical hydrodynamical codes. TRIDENT was originally developed to aid in the interpretation of observations of the circumgalactic medium and intergalactic medium, but it remains a general tool applicable in other contexts.

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Gas Accretion via Lyman Limit Systems

Cited by 10 publications

References 123 publications

Characterizing circumgalactic gas around massive ellipticals at z ∼ 0.4 – I. Initial results★

Characterizing circumgalactic gas around massive ellipticals at z ∼ 0.4 – I. Initial results★

The Cosmic Evolution of the Metallicity Distribution of Ionized Gas Traced by Lyman Limit Systems

Trident: A Universal Tool for Generating Synthetic Absorption Spectra from Astrophysical Simulations

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