An optimal and model-independent measurement of the intracluster pressure profile - I. Methodology and first applications

作者：Aslanbeigi Siavash^*; Lavaux Guilhem; Hajian Amir; Afshordi Niayesh

来源：Monthly Notices of the Royal Astronomical Society, 2013, 435(2): 1788-1808.

DOI：10.1093/mnras/stt1416

• methods: observational
• methods: statistical
• intergalactic medium
• cosmic background radiation
• cosmology: observations
• large-scale structure of Universe

We present a statistically optimal and model-independent method to extract the pressure profile of hot gas in the intracluster medium (ICM). Using the thermal Sunyaev-Zeldovich effect, we constrain the mean pressure profile of the ICM by appropriately considering all primary cosmic microwave background (CMB) and instrumental noise correlations, while using the maximum resolution and sensitivity of all frequency channels. As a first application, we analyse CMB maps of Wilkinson Microwave Anisotropy Probe 9-year data through a study of the Meta-Catalogue of X-ray Detected Clusters of Galaxies. We constrain the universal pressure profile out to 4R(500) with 15 Sigma confidence, though our measurements are only significant out to R-200. Using a temperature profile constrained from X-ray observations, we measure the mean gas mass fraction out to R-200. Within statistical and systematic uncertainties, our constraints are compatible with the cosmic baryon fraction and the expected gas fraction in haloes. While Planck multifrequency CMB data are expected to reduce statistical uncertainties by a factor of similar to 20, we argue that systematic errors in determining mass of clusters dominate the uncertainty in gas mass fraction measurements at the level of similar to 20 per cent.

• 出版日期2013-10