EDP Sciences
Free access
Volume 408, Number 1, September II 2003
Page(s) 43 - 49
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20030954

A&A 408, 43-49 (2003)
DOI: 10.1051/0004-6361:20030954

Measuring $\mathsf{\Omega_{m}}$ using clusters evolution

A. Del Popolo

Dipartimento di Matematica, Università Statale di Bergamo, via dei Caniana 2, 24129 Bergamo, Italy Feza Gürsey Institute, PO Box 6 Çengelköy, Istanbul, Turkey Bo$\rm \breve{g}azi$çi University, Physics Department, 80815 Bebek, Istanbul, Turkey
(Received 7 May 2003 / Accepted 17 June 2003 )

The constraints obtained by several authors (Eke et al. 1998; Henry 2000) on the estimated values of  $\Omega_{\rm m}$, n and  $\sigma_8$ are revisited in the light of recent theoretical developments: 1) new theoretical mass functions; 2) a more accurate mass-temperature relation, also determined for arbitrary  $\Omega_{\rm m}$ and  $\Omega_{\rm\Lambda}$. I re-derive the X-ray Temperature Function (XTF), similarly to Henry (2000) and Eke et al. (1999), re-obtaining the constraints on  $\Omega_{\rm m}$, n, $\sigma_8$. The result shows that changes in the mass function and M-T relation produces an increase in  $\Omega_{\rm m}$ of  $\simeq$ $20\%$ and similar results in  $\sigma_8$ and  n.

Key words: cosmology: theory -- large-scale structure of Universe -- galaxies: formation

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