Journal Article

Mass and gas profiles in A1689: joint X-ray and lensing analysis

Doron Lemze, Rennan Barkana, Tom J. Broadhurst and Yoel Rephaeli

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 386, issue 2, pages 1092-1106
Published in print May 2008 | ISSN: 0035-8711
Published online April 2008 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2008.13116.x
Mass and gas profiles in A1689: joint X-ray and lensing analysis

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We carry out a comprehensive joint analysis of high-quality HST/ACS and Chandra measurements of A1689, from which we derive mass, temperature, X-ray emission and abundance profiles. The X-ray emission is smooth and symmetric, and the lensing mass is centrally concentrated indicating a relaxed cluster. Assuming hydrostatic equilibrium we deduce a 3D mass profile that agrees simultaneously with both the lensing and X-ray measurements. However, the projected temperature profile predicted with this 3D mass profile exceeds the observed temperature by ∼30 per cent at all radii, a level of discrepancy comparable to the level found for other relaxed clusters. This result may support recent suggestions from hydrodynamical simulations that denser, more X-ray luminous small-scale structure can bias observed temperature measurements downward at about the same (∼30 per cent) level. We determine the gas entropy at 0.1rvir (where rvir is the virial radius) to be ∼800 keV cm2, as expected for a high-temperature cluster, but its profile at >0.1rvir has a power-law form with index ∼0.8, considerably shallower than the ∼1.1 index advocated by theoretical studies and simulations. Moreover, if a constant entropy ‘floor’ exists at all, then it is within a small region in the inner core, r < 0.02rvir, in accord with previous theoretical studies of massive clusters.

Keywords: galaxies: clusters: individual: A1689

Journal Article.  12390 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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