The J-PAS survey: The effect of photometric redshift errors on cosmic voids

¹ Tartu Observatory, University of Tartu, Observatooriumi 1, 61602 Tõravere, Estonia
² Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, 05508-090 São Paulo, Brazil
³ Departamento de Astronomia, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, Brazil
⁴ Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia
⁵ Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza San Juan, 1, E-44001 Teruel, Spain
⁶ Observatório Nacional, Ministério da Ciencia, Tecnologia, Inovação e Comunicações, Rua General José Cristino, 77, São Cristóvão, 20921-400 Rio de Janeiro, Brazil
⁷ Instituto de Astrofísica de Andalucía (CSIC), PO Box 3004 18080 Granada, Spain
⁸ Donostia International Physics Centre, Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastian, Spain
⁹ Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
¹⁰ Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, BA, Brazil
¹¹ Department of Astronomy, University of Michigan, 311 West Hall, 1085 South University Ave., Ann Arbor, USA
¹² Departamento de Astronomia, Instituto de Astronomia, Geofísica e Ciências Atmosféricas da USP, Cidade Universitária, 05508-900 São Paulo, SP, Brazil
¹³ Instruments4, 4121 Pembury Place, La Cañada-Flintridge, CA 91011, USA
¹⁴ Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória, ES, Brazil
¹⁵ INAF – Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34131 Trieste, Italy
¹⁶ IFPU – Institute for Fundamental Physics of the Universe, Via Beirut 2, 34151 Trieste, Italy
¹⁷ Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
¹⁸ Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain

^⋆ Corresponding author; jad-alexandru.mansour@ut.ee

Received: 24 October 2024
Accepted: 31 January 2025

Abstract

Aims. We investigated the impact of photometric redshift errors in the ongoing Javalambre Physics of the Accelerating Universe Astrophysical Survey (J-PAS) on void identification and void properties using a watershed-based method. Our aim is to assess the recovery of individual voids and the overall void environment.

Methods. We created galaxy mock catalogues for a redshift of z = 0.1, using the IllustrisTNG300-1 simulation and defining two datasets: an ideal sample (m_r < 21 mag) and a perturbed sample with the Z-coordinate errors mimicking J-PAS’s line-of-sight errors, derived from the precursor miniJPAS survey data. We identified voids using the watershed algorithm ZOBOV.

Results. We found 1065 voids in the ideal sample and 2558 voids in the perturbed sample. The perturbed sample voids have, on average, smaller sizes and denser interiors. We filtered out voids based on density and radius to eliminate overdense and small spurious instances. The stacked density profile of filtered voids in the perturbed sample remains close to the average density, even at the boundary peak, indicating a strong blurring of structures by the redshift errors. The number of the ideal sample voids for which at least 50% of the volume is recovered by a void in the perturbed sample is 53 (29 for the filtered sample). The volume occupied by these voids is less than 10% of the simulation volume. Merging voids in the perturbed sample marginally improves the recovery. The overall volumes defined as voids in the two samples have an overlap of 80%, making up 61% of the simulation box volume.

Conclusions. While some statistical properties of voids might be recovered sufficiently well, the watershed algorithms may not be optimal for recovering the large-scale structure voids if they are applied directly to photometric redshift survey data.