A Comparison of Void-finding Algorithms Using Crossing Numbers

Journal Article · 13 November 2023 · The Astrophysical Journal

DOI: https://doi.org/10.3847/1538-4357/acf4f5 · OSTI ID:2205546

Veyrat, Dahlia  ^[1]; Douglass, Kelly A.  ^[1]; BenZvi, Segev  ^[1]

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1. University of Rochester, NY (United States)

We study how well void-finding algorithms identify cosmic void regions and whether we can quantitatively and qualitatively compare the voids they find with dynamical information from the underlying matter distribution. Using the ORIGAMI algorithm to determine the number of dimensions along which dark matter particles have undergone shell crossing (crossing number) in N-body simulations from the AbacusSummit simulation suite, we identify dark matter particles that have undergone no shell crossing as belonging to voids. We then find voids in the corresponding halo distribution using two different void-finding algorithms: VoidFinder and V², a ZOBOV-based algorithm. The resulting void catalogs are compared to the distribution of dark matter particles to examine how their crossing numbers depend on void proximity. While both algorithms' voids have a similar distribution of crossing numbers near their centers, we find that beyond 0.25 times the effective void radius, voids found by VoidFinder exhibit a stronger preference for particles with low crossing numbers than those found by V². We examine two possible methods of mitigating this difference in efficacy between the algorithms. While we are able to partially mitigate the ineffectiveness of V² by using the distance from the void edge as a measure of centrality, we conclude that VoidFinder more reliably identifies dynamically distinct regions of low crossing number.

• Research Organization: Univ. of Rochester, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); John Templeton Foundation; USDOE
• Grant/Contract Number: SC0008475; 62177
• OSTI ID: 2205546
• Alternate ID(s): OSTI ID: 2474835
• Journal Information: The Astrophysical Journal, Vol. 958, Issue 1; ISSN 0004-637X
• Publisher: IOP PublishingCopyright Statement
• Country of Publication: United States
• Language: English