Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Galaxy groups and clouds in the Local (z~0.01) universe   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|>15deg with radial velocities VLG<3500
km/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/L_K=6 Msun/Lsun.
  The sample of our groups, where each group has n>=4 members, is characterized
by the following medians: mean projected radius <R>=268 kpc, radial velocity
dispersion sigma_V=74 km/s, K-band luminosity L_K=1.2x10^11 Lsun, virial and
projected masses Mvir=2.4x10^12 and Mp=3.3x10^12 Msun, 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, 13.7
Gyr, having the median at 3.8 Gyr.
  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 ten
times brighter than the other group members.
  In total, our algorithm identifies 54 per cent of galaxies to be members of
groups. Together with triple systems and pairs they gather 82 per cent of the
K-band light in Local universe. We have obtained the local value of matter
density to be Omega_m=0.08+-0.02 within a distance of ~40 Mpc assuming H0=73
km/s/Mpc. It is significantly smaller than the cosmic value, 0.28, in the
standard lambdaCDM model. The discrepancy between the global and local
quantities of Omega_m may be caused by the existence of Dark Matter component
unrelated to the virial masses of galaxy systems.

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The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: nlin
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The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
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The categories of this paper are: cs
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: solv-int