Voids in the Las Campanas Redshift Survey versus cold dark matter models |
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| Authors: | V Müller S Arbabi-Bidgoli J Einasto D Tucker |
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| Institution: | Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany;Tartu Observatory, 61602 Tõravere, Estonia;Fermilab, MS 127, PO Box 500, Batavia, IL 60510, USA |
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| Abstract: | We analysed the distribution of void sizes in the two-dimensional slices of the Las Campanas Redshift Survey (LCRS). Fourteen volume-limited subsamples were extracted from the six slices to cover a large part of the survey and to test the robustness of the results against cosmic variance. Thirteen samples were randomly culled to produce homogeneously selected samples. We then studied the relationship between the cumulative area covered by voids and the void size as a property of the void hierarchy. We found that the distribution of void sizes scaled with the mean galaxy separation, λ . In particular, we found that the size of voids covering half of the area is given by D med≈ λ +(12±3) h −1 Mpc. Next, by employing an environmental density threshold criterion to identify mock galaxies, we were able to extend this analysis to mock samples from dynamical N -body simulations of cold dark matter (CDM) models. To reproduce the observed void statistics, overdensity thresholds of δ th≈0,…,1 are necessary. We compared standard (SCDM), open (OCDM), vacuum energy dominated (ΛCDM) and broken scale invariant CDM models (BCDM): we found that both the void size distribution and the two-point correlation function provided important and complementary information on the large-scale matter distribution. The dependence of the void statistics on the threshold criterion for the mock galaxy identification showed that the galaxy biasing was more crucial for the void size distribution than were differences between the cosmological models. |
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| Keywords: | galaxies: formation dark matter large-scale structure of Universe |
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