Issue |
A&A
Volume 483, Number 2, May IV 2008
|
|
---|---|---|
Page(s) | 389 - 400 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:200809550 | |
Published online | 11 March 2008 |
Statistical properties of SZ and X-ray cluster detections
1
ITA, Zentrum für Astronomie, Universität Heidelberg, Albert Überle Str. 2, 69120 Heidelberg, Germany e-mail: francesco@ita.uni-heidelberg.de
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
Received:
8
February
2008
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
~2
1014
. 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
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