A Spectro-photometric Search for Galaxy Clusters in SDSS

TL;DR

This paper presents a new spectro-photometric method to identify galaxy clusters in SDSS data, overcoming fiber collision issues, resulting in the detection of 924 clusters including 212 new ones.

Contribution

The study introduces a novel density measurement technique combining spectroscopic and photometric data to improve galaxy cluster detection accuracy.

Findings

924 galaxy clusters identified in SDSS DR5

212 new galaxy clusters discovered

Method aligns well with visual cluster features

Abstract

Recent large-scale galaxy spectroscopic surveys, such as the Sloan Digital Sky Survey (SDSS), enable us to execute a systematic, relatively-unbiased search for galaxy clusters. Such surveys make it possible to measure the 3-d distribution of galaxies but are hampered by the incompleteness problem due to fiber collisions. In this study we aim to develop a density measuring technique that alleviates the problem and derives densities more accurately by adding additional cluster member galaxies that follow optical color-magnitude relations for the given redshift. The new density measured with both spectroscopic and photometric data shows a good agreement with apparent information on cluster images and is supported by follow-up observations. By adopting this new method, a total of 924 $robust$ galaxy clusters are found from the SDSS DR5 database in the redshift range $0.05<z<0.1$, of which 212 are new. Local maximum-density galaxies successfully represent cluster centers. We provide the cluster catalogue including a number of cluster parameters.