Volume 509, January 2010
|Number of page(s)||9|
|Section||Cosmology (including clusters of galaxies)|
|Published online||22 January 2010|
Galaxy clusters as mirrors of the distant Universe
Implications of the blurring term for the kSZ and ISW effects
Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741
Garching bei München, Germany e-mail: email@example.com
2 Space Research Institute, Russian Academy of Sciences, Profsoyuznaya 84/32, 117997 Moscow, Russia e-mail: firstname.lastname@example.org
Accepted: 26 October 2009
It is well known that Thomson scattering of cosmic microwave background (CMB) photons in galaxy clusters introduces new anisotropies in the CMB radiation field, but still little attention is payed to the fraction of CMB photons that are scattered off the line of sight, causing a slight blurring of the CMB anisotropies present at the moment of scattering. In this work we study this blurring effect and find that it can provide an independent measurement of the cluster's gas mass. Likewise, this effect has a non-negligible impact on estimations of the kSZ effect: it induces a 10% correction in 20-40% of the clusters/groups and a dominant over kSZ correction in % of the clusters in an ideal (noiseless) experiment. For rich clusters, CMB, tSZ and X-ray observations can provide estimates for the amplitude and sign of the blurring effect that can be used for correcting kSZ estimations. We explore the possibility of using this blurring term to probe the CMB anisotropy field at different epochs in our Universe. In particular, we study the required precision in the removal of the kSZ which enables us to detect the blurring term in galaxy cluster populations placed at different redshift shells. By mapping this term in those shells, we provide a tomographic probe for the growth of the Integrated Sachs-Wolfe effect (ISW) during the late evolutionary stages of the Universe. We find that the required precision on the removal of the cluster's peculiar velocity is of the order of 100-200 km s-1 in the redshift range 0.2-0.8, after assuming that all clusters more massive than 10 are observable. These errors are comparable to the total expected linear line of sight velocity dispersion for clusters in WMAPV cosmogony and correspond to a residual level of roughly 900-1800 K per cluster, including all types of contaminants and systematics. Were this precision requirement achieved, then independent constraints on the intrinsic cosmological dipole would be simultaneously provided.
Key words: cosmic microwave background / large-scale structure of Universe
© ESO, 2010
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.