Environment of Compact Groups of Galaxies
Abstract
Fields surrounding 91 compact groups of galaxies in Hickson's catalog have been searched for neighboring galaxies within a radius of 1.0h^-1^ Mpc. Positions, magnitudes, sizes, and morphological types of 2711 galaxies, measured from paper prints of the Palomar Observatory Sky Survey, are used to study the density distribution and fraction of spiral galaxies in the environments of these groups. 71% of the groups shows typical surface densities over 100 times larger than their close environments. 82% show no significant concentrations of galaxies near the groups. The remaining 18% (16 groups) do have significant concentrations of galaxies within a 0.5 h^-1^ Mpc radius. The compact groups have a significantly different distribution of spiral fraction than do their environments, as does the subsample of the 16 groups embedded in a rich environment. There is no correlation between the spiral fraction in a group and in its environment. The mean spiral fraction for the galaxies in the environments is 54%, as compared to 45% for the compact groups. These results contradict the view that most compact groups are a result of chance alignments. Rather, they suggest that the compact group formation process can efficiently operate in regions of relatively low galaxy density.
- Publication:
-
The Astronomical Journal
- Pub Date:
- April 1995
- DOI:
- 10.1086/117377
- Bibcode:
- 1995AJ....109.1476P
- Keywords:
-
- Compact Galaxies;
- Density Distribution;
- Spatial Distribution;
- Spiral Galaxies;
- Astronomical Catalogs;
- Astronomical Satellites;
- Galactic Mass;
- Magnitude;
- Morphology;
- Position (Location);
- Sky Surveys (Astronomy);
- Astrophysics;
- GALAXIES: CLUSTERING;
- GALAXIES: KINEMATICS AND DYNAMICS;
- GALAXIES: INTERACTIONS