Volume 483, Number 2, May IV 2008
|Page(s)||389 - 400|
|Section||Cosmology (including clusters of galaxies)|
|Published online||11 March 2008|
Statistical properties of SZ and X-ray cluster detections
ITA, Zentrum für Astronomie, Universität Heidelberg, Albert Überle Str. 2, 69120 Heidelberg, Germany e-mail: email@example.com
2 Max Planck Institut für Extraterrestrische Physik, 85478 Garching, Germany
3 Max Planck Institut für Astrophysik, 85478 Garching, Germany
4 INAF – Osservatorio Astronomico di Bologna, Via Ranzani 1, 40127 Bologna, Italy
5 Dipartimento di Astronomia, Università di Bologna, Via Ranzani 1, 40127 Bologna, Italy
6 INFN-National Institute for Nuclear Physics, Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
Accepted: 29 February 2008
Aims. We calibrate the number density, completeness, reliability, and the lower mass limit of galaxy-cluster detections through their thermal SZ signal and compare them to X-ray cluster detections.
Methods. We simulate maps of the thermal SZ effect and the X-ray emission from light cones constructed in a large, hydrodynamical, cosmological simulation volume, including realistic noise contributions. The maps are convolved with linear, optimised, single- and multi-band filters to identify local peaks and their signal-to-noise ratios. The resulting peak catalogues are then compared to the halo population in the simulation volume to identify true and spurious detections.
Results. Multi-band filtering improves the statistics of SZ cluster detections considerably compared to single-band filtering. Observations with the characteristics of ACT detect clusters with masses M ≥ 6-91013 , quite independent of redshift, reach 50% completeness at ~1014 and 100% completeness at ~21014 . Samples are contaminated by a few spurious detections, but they are only a small percentage of all detections. This is broadly comparable to X-ray cluster detections with XMM-Newton with 100 ks exposure time in the soft band, except that the mass limit for X-ray detections increases much more steeply with redshift than for SZ detections. A comparison of true and filtered signals in the SZ and X-ray maps confirms that the filters introduce at most a negligible bias.
Key words: cosmology: theory / cosmology: cosmic microwave background / galaxies: clusters: general / X-rays: galaxies: clusters / methods: N-body simulations
© ESO, 2008
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.