2019ApJ...873..124W


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.22CEST02:45:59

2019ApJ...873..124W - Astrophys. J., 873, 124-124 (2019/March-2)

The occurrence of compact groups of galaxies through cosmic time.

WIENS C.D., WENGER T.V., TZANAVARIS P., JOHNSON K.E., GALLAGHER S.C. and XIAO L.

Abstract (from CDS):

We use the outputs of a semianalytical model of galaxy formation run on the Millennium Simulation to investigate the prevalence of 3D compact groups (CGs) of galaxies from z = 11 to 0. Our publicly available code identifies CGs using the 3D galaxy number density, the mass ratio of secondary+tertiary to the primary member, mass density in a surrounding shell, the relative velocities of candidate CG members, and a minimum CG membership of three. We adopt "default" values for the first three criteria, representing the observed population of Hickson CGs at z = 0. The percentage of nondwarf galaxies (M > 5 x 108 h–1 M) in CGs peaks near z ∼ 2 for the default set and in the range of z ∼ 1-3 for other parameter sets. This percentage declines rapidly at higher redshifts (z >= 4), consistent with the galaxy population as a whole being dominated by low-mass galaxies excluded from this analysis. According to the most liberal criteria, <=3% of nondwarf galaxies are members of CGs at the redshift where the CG population peaks. Our default criteria result in a population of CGs at z < 0.03 with number densities and sizes consistent with Hickson CGs. Tracking identified CG galaxies and merger products to z = 0, we find that <=16% of nondwarf galaxies have been CG members at some point in their history. Intriguingly, the great majority (96%) of z = 2 CGs have merged to a single galaxy by z = 0. There is a discrepancy in the velocity dispersions of Millennium Simulation CGs compared to those in observed CGs, which remains unresolved.

Abstract Copyright: © 2019. The American Astronomical Society. All rights reserved.

Journal keyword(s): galaxies: evolution - galaxies: groups: general - galaxies: interactions - galaxies: statistics

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 10563 1
2 NAME Stephan's Quintet CGG 22 35 57.5 +33 57 36           ~ 373 1
3 NGC 7319 Sy2 22 36 03.602 +33 58 33.18   14.57 13.53 12.65   ~ 248 0
4 NGC 7320C G 22 36 20.3667448361 +33 59 06.166668958   17       ~ 41 0
5 NAME Local Group GrG ~ ~           ~ 6661 0

    Equat.    Gal    SGal    Ecl

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2019.10.22-02:45:59

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