J/MNRAS/412/2498 Galaxy groups and clouds in the local universe (Makarov+, 2011)
Galaxy groups and clouds in the local (z∼0.01) universe.
Makarov D., Karachentsev I.
<Mon. Not. R. Astron. Soc., 412, 2498-2520 (2011)>
=2011MNRAS.412.2498M 2011MNRAS.412.2498M
ADC_Keywords: Galaxies, nearby ; Clusters, galaxy
Keywords: catalogues - galaxies: groups: general - cosmological parameters
Abstract:
We present an all-sky catalogue of 395 nearby galaxy groups revealed
in the Local Supercluster and its surroundings. The groups and their
associations are identified among 10914 galaxies at |b|>15° with
radial velocities VLG<3500km/s. Our group-finding algorithm
requires the group members to be located inside their zero-velocity
surface. Hereby, we assume that individual galaxy masses are
proportional to their total K-band luminosities,
M/LK=6M☉/L☉.
The sample of our groups, where each group has n≥4 members, is
characterized by the following medians: mean projected radius
=268kpc, radial velocity dispersion σV=74km/s, K-band
luminosity LK=1.2x1011L☉, virial and projected masses
Mvir=2.4x1012 and Mp=3.3x1012M☉, respectively.
Accounting for measurement error reduces the median masses by 30 per
cent. For 97 per cent of identified groups the crossing time does not
exceed the cosmic time, 13.7Gyr, with the median at 3.8Gyr.
We examine different properties of the groups, in particular of the
known nearby groups and clusters in Virgo and Fornax. About a quarter
of our groups can be classified as fossil groups where the dominant
galaxy is at least 10 times brighter than the other group members.
Description:
We use the HyperLEDA (Paturel et al., 2003,
http://atlas.obs-hp.fr/hyperleda/) and the NED
(http://ned.ipac.caltech.edu) data bases as the main sources of data
on radial velocities, apparent magnitudes, morphological types and
other parameters of galaxies.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 82 395 The main properties of the groups
--------------------------------------------------------------------------------
See also:
J/ApJ/743/123 : Coma I cloud fast motions of galaxies (Karachentsev+, 2011)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Group Principal name of the group's brightest
galaxy, taken, as a rule, from LEDA
15- 16 I2 h RAh Right ascension of group's main member (J2000)
17- 18 I2 min RAm Right ascension of group's main member (J2000)
19- 22 F4.1 s RAs Right ascension of group's main member (J2000)
23 A1 --- DE- Declination sign of group's main member (J2000)
24- 25 I2 deg DEd Declination of the group's main member (J2000)
26- 27 I2 arcmin DEm Declination of the group's main member (J2000)
28- 29 I2 arcsec DEs [0/60] Declination of group's main member (J2000)
31- 33 I3 --- N [4/355] Number of group members with known
radial velocities
35- 38 I4 km/s VLG Mean radial velocity of the group relative to
the centroid of the Local Group
40- 42 I3 km/s sigV Standard deviation of radial velocities of the
group members σV not corrected for the
velocity measurement errors
44- 46 I3 kpc Rh Mean harmonic radius of the group (1)
48- 52 F5.2 [Lsun] logLK Total luminosity of the group in the Ks band (2)
54- 58 F5.2 [Msun] logM Projected mass of the group, as defined by
Heisler et al. (1985ApJ...298....8H 1985ApJ...298....8H)
60- 63 F4.2 [Sun] logM/L [0/3] projected mass-to-total luminosity ratio in
the K band
65- 66 I2 --- T [-5/2] Morphological type of the group's main
member according to the RC2 classification
(de Vaucouleurs et al., 1976RC2...C......0D 1976RC2...C......0D)
68- 71 F4.2 mag Dm21 Difference in apparent K magnitudes of the first
and second members of the group, ranked
by K-luminosity mK(2)-mK
73- 82 A10 --- Assoc Group's membership in an association (3)
--------------------------------------------------------------------------------
Note (1): at its computation the distance to the group was determined
from the mean radial velocity with the Hubble parameter H0=73km/s/Mpc.
Note (2): Luminosity in the photometric Ks band, where M☉,K=3.28mag
(Binney & Merrifield, Galactic Astronomy. Princeton Univ. Press,
Princeton, NJ.)
Note (3): Group's membership in an association (cloud, clan), which is
identified at a higher value of the dimensionless parameter adopted to be
κ=40. Here the name of the association is given by the name of the
group that is dominant in it; as is evident from these data, a significant
number of groups are isolated entities not associated with other
neighbouring groups.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Oct-2014