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Title: A Fundamental Test for Galaxy Formation Models: Matching the Lyman- α Absorption Profiles of Galactic Halos Over Three Decades in Distance

Abstract

Galaxy formation depends critically on the physical state of gas in the circumgalactic medium (CGM) and its interface with the intergalactic medium (IGM), determined by the complex interplay between inflow from the IGM and outflows from supernovae and/or AGN feedback. The average Lyα absorption profile around galactic halos represents a powerful tool to probe their gaseous environments. We compare predictions from Illustris and Nyx hydrodynamical simulations with the observed absorption around foreground quasars, damped Lyα systems, and Lyman-break galaxies. We show how large-scale BOSS and small-scale quasar pair measurements can be combined to precisely constrain the absorption profile over three decades in transverse distance 20 kpc ≲ b ≲ 20 Mpc. Far from galaxies, ≲ 2 Mpc, the simulations converge to the same profile and provide a reasonable match to the observations. This asymptotic agreement arises because the ΛCDM model successfully describes the ambient IGM and represents a critical advantage of studying the mean absorption profile. However, significant differences between the simulations, and between simulations and observations, are present on scales 20 kpc ≲ b ≲ 20 Mpc, illustrating the challenges of accurately modeling and resolving galaxy formation physics. It is noteworthy that these differences are observed as far outmore » as ~2 Mpc, indicating that the "sphere of influence" of galaxies could extend to approximately ~7 times the halo virial radius. Current observations are very precise on these scales and can thus strongly discriminate between different galaxy formation models. We demonstrate that the Lyα absorption profile is primarily sensitive to the underlying temperature-density relationship of diffuse gas around galaxies, and argue that it thus provides a fundamental test of galaxy formation models.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [4]
  1. Max-Planck-Inst. für Astronomie, Heidelberg (Germany); Univ. of Heidelberg, Heidelberg (Germany). International Max Planck Research School for Astronomy and Cosmic Physics
  2. Max-Planck-Inst. für Astronomie, Heidelberg (Germany); Univ. of Edinburgh, Scotland (United Kingdom). Scottish Univ. Physics Alliance (SUPA), Inst. for Astronomy
  3. Max-Planck-Inst. für Astronomie, Heidelberg (Germany); Univ. of California, San Diego, CA (United States). Dept. of Physics
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1493258
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 859; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; cosmology: miscellaneous; galaxies: halos; intergalactic medium; methods: numerical; quasars: absorption lines

Citation Formats

Sorini, Daniele, Oñorbe, José, Hennawi, Joseph F., and Lukić, Zarija. A Fundamental Test for Galaxy Formation Models: Matching the Lyman-α Absorption Profiles of Galactic Halos Over Three Decades in Distance. United States: N. p., 2018. Web. doi:10.3847/1538-4357/aabb52.
Sorini, Daniele, Oñorbe, José, Hennawi, Joseph F., & Lukić, Zarija. A Fundamental Test for Galaxy Formation Models: Matching the Lyman-α Absorption Profiles of Galactic Halos Over Three Decades in Distance. United States. doi:10.3847/1538-4357/aabb52.
Sorini, Daniele, Oñorbe, José, Hennawi, Joseph F., and Lukić, Zarija. Wed . "A Fundamental Test for Galaxy Formation Models: Matching the Lyman-α Absorption Profiles of Galactic Halos Over Three Decades in Distance". United States. doi:10.3847/1538-4357/aabb52. https://www.osti.gov/servlets/purl/1493258.
@article{osti_1493258,
title = {A Fundamental Test for Galaxy Formation Models: Matching the Lyman-α Absorption Profiles of Galactic Halos Over Three Decades in Distance},
author = {Sorini, Daniele and Oñorbe, José and Hennawi, Joseph F. and Lukić, Zarija},
abstractNote = {Galaxy formation depends critically on the physical state of gas in the circumgalactic medium (CGM) and its interface with the intergalactic medium (IGM), determined by the complex interplay between inflow from the IGM and outflows from supernovae and/or AGN feedback. The average Lyα absorption profile around galactic halos represents a powerful tool to probe their gaseous environments. We compare predictions from Illustris and Nyx hydrodynamical simulations with the observed absorption around foreground quasars, damped Lyα systems, and Lyman-break galaxies. We show how large-scale BOSS and small-scale quasar pair measurements can be combined to precisely constrain the absorption profile over three decades in transverse distance 20 kpc ≲ b ≲ 20 Mpc. Far from galaxies, ≲ 2 Mpc, the simulations converge to the same profile and provide a reasonable match to the observations. This asymptotic agreement arises because the ΛCDM model successfully describes the ambient IGM and represents a critical advantage of studying the mean absorption profile. However, significant differences between the simulations, and between simulations and observations, are present on scales 20 kpc ≲ b ≲ 20 Mpc, illustrating the challenges of accurately modeling and resolving galaxy formation physics. It is noteworthy that these differences are observed as far out as ~2 Mpc, indicating that the "sphere of influence" of galaxies could extend to approximately ~7 times the halo virial radius. Current observations are very precise on these scales and can thus strongly discriminate between different galaxy formation models. We demonstrate that the Lyα absorption profile is primarily sensitive to the underlying temperature-density relationship of diffuse gas around galaxies, and argue that it thus provides a fundamental test of galaxy formation models.},
doi = {10.3847/1538-4357/aabb52},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 859,
place = {United States},
year = {2018},
month = {5}
}

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