Filaments in observed and mock galaxy catalogues

¹ Université Lille 1, Laboratoire Paul Painlevé, 59655 Villeneuve d'Ascq Cedex, France e-mail: radu.stoica@math.univ-lille1.fr
² Observatori Astronòmic and Departament d'Astronomia i Astrofísica, Universitat de València, Apartat de correus 22085, 46071 València, Spain e-mail: martinez@uv.es
³ Tartu Observatoorium, Tõravere 61602, Estonia e-mail: saar@aai.ee

Received: 3 July 2009
Accepted: 10 November 2009

Abstract

Context. The main feature of the spatial large-scale galaxy distribution is an intricate network of galaxy filaments. Although many attempts have been made to quantify this network, there is no unique and satisfactory recipe for that yet.

Aims. The present paper compares the filaments in the real data and in the numerical models, to see if our best models reproduce statistically the filamentary network of galaxies.

Methods. We apply an object point process with interactions (the Bisous process) to trace and describe the filamentary network both in the observed samples (the 2dFGRS catalogue) and in the numerical models that have been prepared to mimic the data. We compare the networks.

Results. We find that the properties of filaments in numerical models (mock samples) have a large variance. A few mock samples display filaments that resemble the observed filaments, but usually the model filaments are much shorter and do not form an extended network.

Conclusions. We conclude that although we can build numerical models that are similar to observations in many respects, they may fail yet to explain the filamentary structure seen in the data. The Bisous-built filaments are a good test for such a structure.