2008A&A...486..113M


C.D.S. - SIMBAD4 rel 1.7 - 2020.05.27CEST10:38:57

2008A&A...486..113M - Astronomy and Astrophysics, volume 486, 113-117 (2008/7-4)

The nature of the nearest compact group of galaxies from precise distance measurements.

MAMON G.A.

Abstract (from CDS):

Compact groups (CGs) of galaxies, similar to those catalogued by Hickson, appear to be the densest galaxy structures in the Universe. Redshift information is insufficient to determine whether a CG is roughly as dense in three dimensions as it appears in projection, or whether it is caused by a chance alignment along the line of sight within a larger galaxy system. Recent precise distance measurements help probe the nature of the nearest CG, situated in the Virgo cluster, whose dominant member is M60. The isolated status of the CG is reassessed with recent photometry and a statistical analysis is performed on the surface brightness fluctuation (SBF) distances measured by Mei et al. in Virgo, for 4 of the 5 CG members. The neighboring galaxy NGC 4606 appears (with 80-90% confidence) to be too faint to affect the isolated status of the CG. Taken at face value, the SBF distances suggest that M59 and NGC 4660 lie roughly 2Mpc to the foreground of M60, NGC 4638, and the bulk of the Virgo cluster. The statistical analysis confirms that the CG is, indeed, the result of a chance alignment of its galaxies, with NGC 4638 lying at least 800kpc further away (with 99% confidence) than either M59 or NGC 4660. The first two galaxy distances are consistent with M59 and NGC 4660 constituting a tight pair. The dominant galaxy, M60, is at least 440 kpc more distant (95% confidence) than the M59+NGC 4660 pair, and over 1Mpc (99% confidence) more distant if one uses the broken linear calibration of the SBF distances. This work constitutes the first direct analysis of the nature of a compact group of galaxies. Chance alignments of galaxies represent a realistic alternative to truly dense groups to explain the nature of CGs. With current SBF distance accuracies, one could determine the nature of HCG 68 in the same way.

Abstract Copyright:

Journal keyword(s): galaxies: clusters: individual: Virgo - galaxies: distances and redshifts

Status at CDS:  

Simbad objects: 13

goto Full paper

goto View the reference in ADS

Number of rows : 13

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 HCG 54 CGG 11 29 15 +20 34.7           ~ 49 0
2 M 86 GiG 12 26 11.814 +12 56 45.49 10.32 9.83 8.90   7.50 ~ 1008 1
3 NAME Vir I ClG 12 26 32.1 +12 43 24   10.00 8.49     ~ 5788 0
4 M 49 Sy2 12 29 46.798 +08 00 01.48   13.21 12.17     ~ 1953 2
5 M 87 BiC 12 30 49.42338230 +12 23 28.0438581 10.16 9.59 8.63   7.49 ~ 6165 3
6 NGC 4606 GiP 12 40 57.557 +11 54 43.87   12.7       ~ 133 0
7 M 59 GiG 12 42 02.322 +11 38 48.95   11.0       ~ 653 0
8 NGC 4638 GiP 12 42 47.4239000267 +11 26 32.961349655   12.2 11.23     ~ 263 1
9 NGC 4647 H2G 12 43 32.542 +11 34 56.89   12.5 12.5     ~ 375 0
10 M 60 GiP 12 43 40.008 +11 33 09.40   10.3       ~ 1247 0
11 NAME M 60 Group GrG 12 43.7 +11 33           ~ 5 0
12 NGC 4660 GiP 12 44 31.9848549289 +11 11 25.730688043   12.1       ~ 395 0
13 HCG 68 CGG 13 53 40.9 +40 19 07     12.4     ~ 107 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2008A&A...486..113M and select 'bookmark this link' or equivalent in the popup menu


2020.05.27-10:38:57

© Université de Strasbourg/CNRS

    • Contact