On Cooling Flows and the Sunyaev-Zeldovich Effect

Majumdar, Subhabrata and Nath, Biman B (2000) On Cooling Flows and the Sunyaev-Zeldovich Effect. In: Astrophysical Journal, 542 (2). pp. 597-607.

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Abstract

We study the effect of cooling flows in galaxy clusters on the Sunyaev-Zeldovich (SZ) distortion and the possible cosmological implications. The SZ effect, along with X-ray observations of clusters, is used to determine the Hubble constant $H_o$, Blank-sky surveys of SZ effect are being planned to constrain the geometry of the universe through cluster counts. It is also known that a significant fraction of clusters have cooling flows in them, which change the pressure profile of intracluster gas. Since the SZ decrement depends essentially on the pressure profile, it is important to study possible changes in the determination of cosmological parameters in the presence of a cooling flow.We build several representative models of cooling flows and compare the results with the corresponding case of gas in hydrostatic equilibrium. We find that cooling flows can lead to an overestimation of the Hubble constant. Specifically, we find that for realistic models of cooling flow with mass deposition (varying with radius), there is of the order of m5 ~10% deviation in the estimated value of the Hubble constant (from that for gas without a cooling flow) even after excluding ~80% of the cooling-flow region from the analysis. We also discuss the implications of using cluster counts from SZ observations to constrain other cosmological parameters in the presence of clusters with cooling flows.

Item Type:	Journal Article
Publication:	Astrophysical Journal
Publisher:	The American Astronomical Society
Additional Information:	Copyright of this article belongs The American Astronomical Society.
Keywords:	Cooling flows;Cosmic microwave background;Distance scale; Galaxies:clusters:general;Large-scale structure of universe
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	29 Aug 2006
Last Modified:	19 Sep 2010 04:30
URI:	http://eprints.iisc.ac.in/id/eprint/8095

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