Journal Article

Constraining the cosmological baryon density with X-ray clusters

Claudio Gheller, Ornella Pantano and Lauro Moscardini

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 296, issue 1, pages 85-99
Published in print May 1998 | ISSN: 0035-8711
Published online May 1998 | e-ISSN: 1365-2966 | DOI:
Constraining the cosmological baryon density with X-ray clusters

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We study the properties of X-ray galaxy clusters in four cold dark matter models with different baryon fractions ΩBM, ranging from 5 to 20 per cent. By using an original three-dimensional hydrodynamic code based on the piecewise parabolic method, we run simulations on a box with a size of 64 h−1 Mpc and we identify the clusters by selecting the peaks in the X-ray luminosity field. We analyse these mock catalogues by computing the mass function, the luminosity function, the temperature distribution and the luminosity–temperature relation. By comparing the predictions of the different models to a series of recent observational results, we find that only the models with low baryonic content agree with the data, while models with larger baryon fraction are well outside the 1σ error bars. In particular, the analysis of the luminosity functions, both bolometric and in the energy band [0.5–2] keV, requires ΩBM ≲ 0.05 when we fix the values h = 0.5 and n = 0.8 for the Hubble parameter and the primordial spectral index, respectively. Moreover we find that, independently of the cosmological scenario, all the considered quantities have very little redshift evolution, particularly between z = 0.5 and 0.

Keywords: hydrodynamics; galaxies: clusters: general; dark matter; large-scale structure of Universe; X-rays: galaxies; X-rays: general

Journal Article.  0 words. 

Subjects: Astronomy and Astrophysics

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