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

Authors :
Doron Lemze
Rennan Barkana
Yoel Rephaeli
Tom Broadhurst
Source :
Monthly Notices of the Royal Astronomical Society. 386:1092-1106
Publication Year :
2008
Publisher :
Oxford University Press (OUP), 2008.

Abstract

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% 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%) level. We determine the gas entropy at 0.1r_{vir} (where r_{vir} is the virial radius) to be ~800 keV cm^2, as expected for a high temperature cluster, but its profile at >0.1r_{vir} 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<br />18 pages, 20 figures, 7 tables, accepted for publication in MNRAS, minor changes to match published version

Details

ISSN :
13652966 and 00358711
Volume :
386
Database :
OpenAIRE
Journal :
Monthly Notices of the Royal Astronomical Society
Accession number :
edsair.doi.dedup.....b21a9a9303307f6b88dd2c7771945579
Full Text :
https://doi.org/10.1111/j.1365-2966.2008.13116.x