Artículo de revista
A 3D Voronoi+Gapper Galaxy Cluster Finder in Redshift Space to z ∼ 0.2. II. An Abundant Cluster Population Dominated by Late-type Galaxies Unveiled
Fecha
2020Registro en:
The Astrophysical Journal, 890:91 (2pp), 2020 February 10
10.3847/1538-4357/ab6b26
Autor
Campusano Brown, Luis
Marinello, Gabriel
Clowes, Roger G.
Haines, Christopher P.
Pereira, Sebastián
Pizarro, Daniel
Hitschfeld Kahler, Nancy
Söchting, Ilona K.
Institución
Resumen
We identify 1901 galaxy clusters (N-g >= 2) with the VoML+G algorithm (Paper I) on the Two-Degree Field Galaxy Redshift Survey. We present the 341 clusters with at least 10 galaxies that are within 0.009 < z < 0.14 (the Catalog), of which 254 (similar to 75%) have counterparts in the literature (NED), with the remainder (87) plausibly "new" because of incompleteness of previous searches or unusual galaxy contents. The 207 clusters within z = 0.04-0.09 are used to study the properties of the galaxy systems in the nearby universe, including their galaxy contents parameterized by the late-type galaxy fractions (f(L)). For this nearly complete cluster subsample, we find the following: (i) 63% are dominated by early-type galaxies (i.e., the late-type-poor clusters, f(L) < 0.5) with corresponding mean multiplicity and logarithmic virial mass (in units of M-circle dot) of 22 +/- 1 and 12.91 +/- 0.04, respectively; and (ii) 37% are dominated by late-type galaxies (i.e., the late-type-rich clusters, f(L) >= 0.5) with corresponding mean multiplicity and logarithmic virial mass (in units of M-circle dot) of 15.7 +/- 0.9 and 12.66 +/- 0.07, respectively. The statistical analysis of the late-type fraction distribution supports, with a 3 sigma confidence level, the presence of two population components. It is suggested that the late-type-poor galaxy systems reflect and extend the class of Abell-APM-EDCC clusters and that the late-type-rich systems (similar to one-third of the total) belong to a new, previously unappreciated class. The late-type-rich clusters, on average high mass-to-light ratio systems, appear to be more clustered on large scales than the late-type-poor clusters. A class of late-type-rich clusters is not predicted by current theory.