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A comparison of observed and simulated absorption from H I, C IV, and Si IV around z ≈ 2 star-forming galaxies suggests redshift–space distortions are due to inflows

Turner, Monica L. and Schaye, Joop and Crain, Robert A. and Rudie, Gwen and Steidel, Charles C. and Strom, Allison and Theuns, Tom (2017) A comparison of observed and simulated absorption from H I, C IV, and Si IV around z ≈ 2 star-forming galaxies suggests redshift–space distortions are due to inflows. Monthly Notices of the Royal Astronomical Society, 471 (1). pp. 690-705. ISSN 0035-8711. https://resolver.caltech.edu/CaltechAUTHORS:20170911-124424108

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Abstract

We study H I and metal-line absorption around z ≈ 2 star-forming galaxies by comparing an analysis of data from the Keck Baryonic Structure Survey to mock spectra generated from the Evolution and Assembly of Galaxies and their Environments (EAGLE) cosmological, hydrodynamical simulations. We extract sightlines from the simulations and compare the properties of the absorption by H I, C IV, and Si IV around simulated and observed galaxies using pixel optical depths. We mimic the resolution, pixel size, and signal-to-noise ratio of the observations, as well as the distributions of impact parameters and galaxy redshift errors. We find that the EAGLE reference model is in excellent agreement with the observations. In particular, the simulation reproduces the high metal-line optical depths found at small galactocentric distances, the optical depth enhancements out to impact parameters of 2 proper Mpc, and the prominent redshift–space distortions which we find are due to peculiar velocities rather than redshift errors. The agreement is best for halo masses ∼10^(12.0) M⊙, for which the observed and simulated stellar masses also agree most closely. We examine the median ion mass-weighted radial gas velocities around the galaxies, and find that most of the gas is infalling, with the infall velocity depending on halo rather than stellar mass. From this, we conclude that the observed redshift–space distortions are predominantly caused by infall rather than outflows.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1093/mnras/stx1616DOIArticle
https://arxiv.org/abs/1703.00086arXivDiscussion Paper
ORCID:
AuthorORCID
Rudie, Gwen0000-0002-8459-5413
Steidel, Charles C.0000-0002-4834-7260
Strom, Allison0000-0001-6369-1636
Additional Information:© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 June 23. Received 2017 May 17; in original form 2017 February 28. Published: 30 June 2017. We would like to thank the anonymous referee for a constructive report that improved this article. This work used the DiRAC Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by BIS National E-infrastructure capital grant ST/K00042X/1, STFC capital grants ST/H008519/1 and ST/K00087X/1, STFC DiRAC Operations grant ST/K003267/1 and Durham University. DiRAC is part of the National E-Infrastructure. This work was supported by the Netherlands Organisation for Scientific Research (NWO), through VICI grant 639.043.409 and by the European Research Council under the European Union's Seventh Framework Programme (FP7/2007- 2013)/ERC Grant agreement 278594-GasAroundGalaxies. RAC is a Royal Society University Research Fellow.
Group:Astronomy Department
Funders:
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/K00042X/1
Science and Technology Facilities Council (STFC)ST/H008519/1
Science and Technology Facilities Council (STFC)ST/K00087X/1
Science and Technology Facilities Council (STFC)ST/K003267/1
Durham UniversityUNSPECIFIED
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)639.043.409
European Research Council (ERC)278594
Royal SocietyUNSPECIFIED
Subject Keywords:galaxies: formation – intergalactic medium – quasars: absorption lines
Issue or Number:1
Record Number:CaltechAUTHORS:20170911-124424108
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170911-124424108
Official Citation:Monica L. Turner, Joop Schaye, Robert A. Crain, Gwen Rudie, Charles C. Steidel, Allison Strom, Tom Theuns; A comparison of observed and simulated absorption from H I, C IV, and Si IV around z ≈ 2 star-forming galaxies suggests redshift–space distortions are due to inflows, Monthly Notices of the Royal Astronomical Society, Volume 471, Issue 1, 11 October 2017, Pages 690–705, https://doi.org/10.1093/mnras/stx1616
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:81294
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:11 Sep 2017 19:56
Last Modified:04 Dec 2019 23:24

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