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Title: Cosmological simulations of isotropic conduction in galaxy clusters

Abstract

Simulations of galaxy clusters have a difficult time reproducing the radial gas-property gradients and red central galaxies observed to exist in the cores of galaxy clusters. Thermal conduction has been suggested as a mechanism that can help bring simulations of cluster cores into better alignment with observations by stabilizing the feedback processes that regulate gas cooling, but this idea has not yet been well tested with cosmological numerical simulations. Here we present cosmological simulations of 10 galaxy clusters performed with five different levels of isotropic Spitzer conduction, which alters both the cores and outskirts of clusters, though not dramatically. In the cores, conduction flattens central temperature gradients, making them nearly isothermal and slightly lowering the central density, but failing to prevent a cooling catastrophe there. Conduction has little effect on temperature gradients outside of cluster cores because outward conductive heat flow tends to inflate the outer parts of the intracluster medium (ICM), instead of raising its temperature. In general, conduction tends reduce temperature inhomogeneity in the ICM, but our simulations indicate that those homogenizing effects would be extremely difficult to observe in ∼5 keV clusters. Outside the virial radius, our conduction implementation lowers the gas densities and temperatures because itmore » reduces the Mach numbers of accretion shocks. We conclude that, despite the numerous small ways in which conduction alters the structure of galaxy clusters, none of these effects are significant enough to make the efficiency of conduction easily measurable, unless its effects are more pronounced in clusters hotter than those we have simulated.« less

Authors:
; ; ;  [1]
  1. Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)
Publication Date:
OSTI Identifier:
22341944
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 778; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALIGNMENT; COMPUTERIZED SIMULATION; DENSITY; EFFICIENCY; FEEDBACK; GALAXIES; GALAXY CLUSTERS; GAS COOLING; HEAT FLUX; HYDRODYNAMICS; KEV RANGE; TEMPERATURE GRADIENTS; THERMAL CONDUCTION

Citation Formats

Smith, Britton, O'Shea, Brian W., Voit, G. Mark, Ventimiglia, David, and Skillman, Samuel W., E-mail: smit1685@msu.edu. Cosmological simulations of isotropic conduction in galaxy clusters. United States: N. p., 2013. Web. doi:10.1088/0004-637X/778/2/152.
Smith, Britton, O'Shea, Brian W., Voit, G. Mark, Ventimiglia, David, & Skillman, Samuel W., E-mail: smit1685@msu.edu. Cosmological simulations of isotropic conduction in galaxy clusters. United States. https://doi.org/10.1088/0004-637X/778/2/152
Smith, Britton, O'Shea, Brian W., Voit, G. Mark, Ventimiglia, David, and Skillman, Samuel W., E-mail: smit1685@msu.edu. 2013. "Cosmological simulations of isotropic conduction in galaxy clusters". United States. https://doi.org/10.1088/0004-637X/778/2/152.
@article{osti_22341944,
title = {Cosmological simulations of isotropic conduction in galaxy clusters},
author = {Smith, Britton and O'Shea, Brian W. and Voit, G. Mark and Ventimiglia, David and Skillman, Samuel W., E-mail: smit1685@msu.edu},
abstractNote = {Simulations of galaxy clusters have a difficult time reproducing the radial gas-property gradients and red central galaxies observed to exist in the cores of galaxy clusters. Thermal conduction has been suggested as a mechanism that can help bring simulations of cluster cores into better alignment with observations by stabilizing the feedback processes that regulate gas cooling, but this idea has not yet been well tested with cosmological numerical simulations. Here we present cosmological simulations of 10 galaxy clusters performed with five different levels of isotropic Spitzer conduction, which alters both the cores and outskirts of clusters, though not dramatically. In the cores, conduction flattens central temperature gradients, making them nearly isothermal and slightly lowering the central density, but failing to prevent a cooling catastrophe there. Conduction has little effect on temperature gradients outside of cluster cores because outward conductive heat flow tends to inflate the outer parts of the intracluster medium (ICM), instead of raising its temperature. In general, conduction tends reduce temperature inhomogeneity in the ICM, but our simulations indicate that those homogenizing effects would be extremely difficult to observe in ∼5 keV clusters. Outside the virial radius, our conduction implementation lowers the gas densities and temperatures because it reduces the Mach numbers of accretion shocks. We conclude that, despite the numerous small ways in which conduction alters the structure of galaxy clusters, none of these effects are significant enough to make the efficiency of conduction easily measurable, unless its effects are more pronounced in clusters hotter than those we have simulated.},
doi = {10.1088/0004-637X/778/2/152},
url = {https://www.osti.gov/biblio/22341944}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 778,
place = {United States},
year = {Sun Dec 01 00:00:00 EST 2013},
month = {Sun Dec 01 00:00:00 EST 2013}
}