The redshift-space two-point correlation function of galaxy groups in the CfA2 and SSRS2 surveys

Citation
M. Girardi et al., The redshift-space two-point correlation function of galaxy groups in the CfA2 and SSRS2 surveys, ASTRON ASTR, 353(1), 2000, pp. 57-62
Citations number
46
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
00046361 → ACNP
Volume
353
Issue
1
Year of publication
2000
Pages
57 - 62
Database
ISI
SICI code
0004-6361(200001)353:1<57:TRTCFO>2.0.ZU;2-R
Abstract
We measure the two-point redshift-space correlation function of loose group s of galaxies, xi(GG)(s), for the combined CfA2 and SSRS2 surveys. Our comb ined group catalog constitutes the largest homogeneous sample available (88 5 groups). We compare xi(GG)(s) with the correlation function of galaxies, xi(gg) (s), in the same volume. We find that groups are significantly more clustered than galaxies: (xi(GG) / xi(gg) ) =1.64+/-0.16 A similar result h olds when we analyze a volume-limited sample (distance limit 78 h(-1) Mpc) of 139 groups. For these groups, with median velocity dispersion sigma(v) s imilar to 200km s(-1) and mean group separation d similar to 16 h(-1) Mpc, we find that the correlation length is s(0) = 8 +/- 1 h(-1) Mpc, which is s ignificantly smaller than that found for rich clusters. We conclude that cl ustering properties of loose groups of galaxies are intermediate between ga laxies and rich clusters. Moreover, we find evidence that group clustering depends on physical properties of groups: correlation strengthens for incre asing sigma(v).