Journal Article

Imprints of primordial non-Gaussianities in X-ray and SZ signals from galaxy clusters

M. Roncarelli, L. Moscardini, E. Branchini, K. Dolag, M. Grossi, F. Iannuzzi and S. Matarrese

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 402, issue 2, pages 923-933
Published in print February 2010 | ISSN: 0035-8711
Published online February 2010 | e-ISSN: 1365-2966 | DOI:
Imprints of primordial non-Gaussianities in X-ray and SZ signals from galaxy clusters

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Several inflationary models predict the possibility that the primordial perturbations of the density field may contain a degree of non-Gaussianity which would influence the subsequent evolution of cosmic structures at large scales. In order to study their impact, we use a set of three cosmological dark-matter-only simulations starting from initial conditions with different levels of non-Gaussianity: fNL= 0, ±100. More specifically, we focus on the distribution of galaxy clusters at different redshifts and, using suitable scaling relations, we determine their X-ray and Sunyaev–Zel'dovich signals. Our analysis allows us to estimate the differences in log N–log S and log N–log Y due to the different initial conditions and to predict the cluster counts at different redshifts expected for future surveys (eROSITA and SPT). We also use a second set of simulations assuming a different cosmological scenario to estimate how the dependence on fNL is degenerate with respect to other parameters. Our results indicate that the effects introduced by a realistic amount of primordial non-Gaussianity are small when compared to the ones connected with current uncertainties in cosmological parameters, particularly with σ8. However, if future surveys will be associated with optical follow-up campaigns to determine the cluster redshift, an analysis of the samples at z > 1 can provide significant constraints on fNL. In particular, we predict that the SPT cluster survey will be able to detect ∼1000 clusters at z > 1 for the Gaussian case, with a difference of 15–20 per cent associated with fNL=±100.

Keywords: methods: N-body simulations; methods: statistical; galaxies: clusters: general; cosmology: theory; large-scale structure of Universe; X-rays: galaxies: clusters

Journal Article.  8361 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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