NONEQUILIBRIUM ELECTRONS AND THE SUNYAEV-ZEL'DOVICH EFFECT OF GALAXY CLUSTERS

Journal Article · Mon Aug 10 04:00:00 EDT 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/701/1/L16; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21313697

Rudd, Douglas H ^[1]; Nagai, Daisuke ^[2]

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1. School of Natural Sciences, Institute for Advanced Study, Princeton, NJ 08540 (United States)
2. Department of Physics, Yale University, New Haven, CT 06520 (United States)

We present high-resolution cosmological hydrodynamic simulations of three galaxy clusters employing a two-temperature model for the intracluster medium. We show that electron temperatures in cluster outskirts are significantly lower than the mean gas temperature, because Coulomb collisions are insufficient to keep electrons and ions in thermal equilibrium. This deviation is larger in more massive and less relaxed systems, ranging from 5% in relaxed clusters to 30% for clusters undergoing major mergers. The presence of nonequilibrium electrons leads to significant suppression of the Sunyaev-Zel'dovich effect (SZE) signal at large cluster-centric radius. The suppression of the electron pressure also leads to an underestimate of the hydrostatic mass. Merger-driven, internal shocks may also generate significant populations of nonequilibrium electrons in the cluster core, leading to a 5% bias on the integrated SZ mass proxy during cluster mergers.

• OSTI ID: 21313697
• Journal Information: Astrophysical Journal (Online), Journal Name: Astrophysical Journal (Online) Journal Issue: 1 Vol. 701; ISSN 1538-4357
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
79 ASTRONOMY AND ASTROPHYSICS
ELECTRON TEMPERATURE
ELECTRONS
GALAXY CLUSTERS
MASS
SIGNALS
SIMULATION
THERMAL EQUILIBRIUM