Optical Studies of Small Groups of Galaxies

1978 ◽  
pp. 21-29
Author(s):  
Edwin L. Turner
Keyword(s):  
Small Groups ◽  
Optical Studies ◽  
Groups Of Galaxies

scholarly journals Optical Studies of Small Groups of Galaxies

1978 ◽  
Vol 79 ◽  
pp. 21-29
Author(s):  
Edwin. L. Turner
Keyword(s):  
Small Groups ◽  
Local Group ◽  
Optical Studies ◽  
Substantial Fraction ◽  
Groups Of Galaxies ◽  
Wide Range

Galaxies occur in a wide variety of systems ranging from binary pairs through small groups to rich clusters. These systems in turn possess a wide range of densities, with typical separations between bright (L ≫ L* = 3.4 × 1010 L⊙) galaxies varying from ≲ 10 kpc up to ~ 1 Mpc. Among the most common of these systems are small, loose groups containing ≲ 10 bright galaxies with separations ≳ 100 kpc. Such systems probably contain a substantial fraction of all galaxies (de Vaucouleurs 1975; van den Bergh 1962; Karachentseva 1973). Familiar examples include the Local Group and M81 group.

scholarly journals On the Formation of Small Groups of Galaxies at High Redshifts

2000 ◽  
Vol 174 ◽  
pp. 412-422
Author(s):  
William C. Saslaw
Keyword(s):  
Velocity Distribution ◽  
Small Groups ◽  
High Redshift ◽  
Distribution Functions ◽  
Many Body ◽  
Redshift Distribution ◽  
Groups Of Galaxies ◽  
Velocity Distribution Functions ◽  
Free Parameters

AbstractCosmological many-body clustering agrees with the spatial and velocity distribution functions of galaxies at low redshifts, and it can be extended to high redshifts z ≈ 3 or more. The high redshift distribution functions are predicted to have a particular form. In the simplest case, there are no free parameters in this prediction, but the degree of clustering depends sensitively on Ω0. Current observations of small groups at high redshifts suggest that Ω0 = 0.3 ± 0.2 for Einstein-Friedmann cosmologies.

scholarly journals Small Galaxy Groups in the Universe

2000 ◽  
Vol 174 ◽  
pp. 209-216
Author(s):  
A. Cavaliere
Keyword(s):  
Small Groups ◽  
Groups Of Galaxies ◽  
Galaxy Groups ◽  
Intracluster Gas ◽  
The Universe

AbstractI discuss the steering role played by small groups of galaxies concerning sources and structures on widely different scales: the very compact quasars, and the extended atmospheres of hot intracluster gas. The evolution of such sources out to substantial z is ruled by astrophysical processes taking place in early small groups.

scholarly journals Collisional Ring Galaxies in Small Groups

2000 ◽  
Vol 174 ◽  
pp. 277-280
Author(s):  
C. Horellou
Keyword(s):  
High Resolution ◽  
Numerical Model ◽  
Numerical Simulations ◽  
Small Groups ◽  
Large Scale ◽  
Rotating Disk ◽  
Groups Of Galaxies ◽  
Ring Galaxies ◽  
History Of

AbstractThe probability of plunging orbits is enhanced in groups of galaxies and indeed, observations show that ring galaxies, which are believed to form when a galaxy passes through the center of a larger rotating disk, are often found in small groups. Numerical simulations combined with a knowledge of the large-scale H I distribution provide strong constraints on the dynamical history of these systems and on the identity of the intruder. Here we present a numerical model of the Cartwheel galaxy which supports the suggestion that the most distant companion is the intruder. We also present high-resolution H I observations of the more irregular system Arp 119 that reveal a possible connection to the most distant companion.

scholarly journals Dust in Nearby Groups of Galaxies?

1990 ◽  
Vol 139 ◽  
pp. 375-376
Author(s):  
M. Girardi ◽  
G. Giuricin ◽  
F. Mardirossian ◽  
M. Mezzetti
Keyword(s):  
Optical Depth ◽  
Small Groups ◽  
Negative Correlation ◽  
Evolutionary Stage ◽  
Nearby Galaxy ◽  
Groups Of Galaxies ◽  
Galaxy Groups ◽  
Redshift Galaxies

The excess of higher redshift galaxies relative to the brightest member, found by several authors in poor, loose groups, is found to be present also in nearby, small groups identified by Geller and Huchra (1983) in the Center for Astrophysics Survey. This effect is explained as being due to the presence of diffuse intragroup dust together with an early evolutionary stage of nearby galaxy groups. An expected negative correlation between color excesses of galaxies and the velocity relative to the brightest member is found to be highly significant for both B-V and U-B colors. The optical depth produced by dust in groups turns out to be on the order of one, with a density of about 10−29 g/cm3.

scholarly journals Abundances of the Very Light Elements (D, 3He, 4He and 7LI) And Primordial Nucleosynthesis

1986 ◽  
Vol 7 ◽  
pp. 377-382
Author(s):  
Jean Audouze
Keyword(s):  
Small Groups ◽  
Big Bang ◽  
Galactic Evolution ◽  
Light Elements ◽  
Big Bang Nucleosynthesis ◽  
Primordial Nucleosynthesis ◽  
Groups Of Galaxies

AbstractThe determinations of the primordial abundances of D, 3He, 4He and 7Li play a major role in building up models of Big Bang nucleosynthesis. Much progress has been made recently in that respect but there are still large uncertainties on these determinations. Although canonical Big Bang models predicting a cosmological baryonic parameter ΩB ~ 0.10 consistent with the dynamics of small groups of galaxies and three different families of neutrinos seem to be the most appropriate in accounting for these abundances, the simplest models of galactic evolution lead to discrepant comparisons concerning D and 4He. The relatively small abundance of 4He might challenge the canonical Big Bang models unless specific models of galactic evolution are invoked.

Photographic photometry of two small groups of galaxies

Astrophysics ◽  
1994 ◽  
Vol 36 (3) ◽  
pp. 205-216
Author(s):  
R. K. Shahbazian ◽  
P. Notni ◽  
F. W. Baier
Keyword(s):  
Small Groups ◽  
Groups Of Galaxies ◽  
Photographic Photometry

Nearby Small Groups of Galaxies

1978 ◽  
pp. 31-47 ◽  
Author(s):  
R. Brent Tully ◽  
J. Richard Fisher
Keyword(s):  
Small Groups ◽  
Groups Of Galaxies
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