The Size, Shape, and Orientation of Cosmological Voids in the Sloan Digital Sky Survey

Abstract

We present a detailed description of our void finding algorithm which is an extension of the prescription by Hoyle and Vogeley. We include a discussion of the reproducibility and robustness of the algorithm as well as the statistical significance of the detected voids. We apply our void finder to the Data Release 5 of the Sloan Digital Sky Survey and identify 232 cosmological voids. A void catalog which contains the most salient properties of the detected voids is created. We present a statistical analysis of the distribution of the size, shape, and orientation of our identified cosmological voids. We also investigate possible trends with redshift for 0.04 z 0.16. We compare our results to those from an identical analysis of a mock catalog based on the ΛCDM model and find reasonable agreement. However, some statistically significant differences in the overall orientation of cosmological voids are exhibited and will have to be reconciled by further refinement of the simulations.

Probing supervoids with weak lensing

“…In order to find voids with haloes, we ran the publicly available VoidFinder code (see details in Foster & Nelson 2009;Higuchi et al 2013). In the VoidFinder, the space is divided into cells and then a sphere is enlarged with respect to a cell until the edge of the sphere reaches the third nearest halo.…”

Precision cosmology with voids: definition, methods, dynamics

“…The void finders of the first class try to find emptier regions in a distribution of points, which in actual catalogues correspond to galaxies. The void finder developed by El‐Ad et al (1997), and one of its later versions by Hoyle & Vogeley (2002), is popularly used in observations (Hoyle & Vogeley 2004; Hoyle et al 2005; Tikhonov & Karachentsev 2006; Foster & Nelson 2009). In these void finders, the first step consists in classifying galaxies in two types.…”

“…They are separated in three broad classes. In the first class, the void finders try to find regions empty of galaxies (Kauffmann & Fairall 1991; El‐Ad, Piran & Dacosta 1997; Hoyle & Vogeley 2002; Patiri et al 2006; Foster & Nelson 2009). The second class of void finders try to identify voids as geometrical structures in the dark matter distribution traced by galaxies (Plionis & Basilakos 2002; Colberg et al 2005; Shandarin et al 2006; Platen, van de Weygaert & Jones 2007; Neyrinck 2008).…”

Cosmic voids in Sloan Digital Sky Survey Data Release 7

“…For the purpose of finding voids in redshift survey observations, methods that are applicable to the distribution of galaxies include Kauffmann & Fairall (1991), El‐Ad & Piran (1997), Aikio & Maehoenen (1998), Hoyle & Vogeley (2002), Neyrinck (2008) and Aragon‐Calvo, van de Weygaert & Araya‐Melo (2010). Examples of applications of such methods to galaxy redshift surveys include analyses of the Southern Sky Redshift Survey (Pellegrini, da Costa & de Carvalho 1989), the first slice of the Center for Astrophysics Redshift Survey (Slezak, de Lapparent & Bijaoui 1993), as well as the full extension of the CfA Redshift Survey (Hoyle & Vogeley 2002), the IRAS 1.2 Jy and Optical Redshift Surveys (El‐Ad, Piran & Dacosta 1997; El‐Ad & Piran 1997, 2000), the Las Campanas Redshift Survey (Müller, Arbabi‐Bidgoli & Einasto 2000), the IRAS PSCz Survey (Hoyle & Vogeley 2002; Plionis & Basilakos 2002), the 2dFGRS (Hoyle & Vogeley 2004; Ceccarelli et al 2006; Tikhonov 2006) and preliminary data from the SDSS (Tikhonov 2007; Foster & Nelson 2009).…”