Low Density Structures in the Local Universe. I. Diffuse Agglomerates of
  Galaxies
  This paper is the first of a series considering the properties of
distribution of nearby galaxies in the low density regions. Among 7596 galaxies
with radial velocities V_{LG}<3500 km/s, absolute magnitudes M_K<-18.4^m$, and
Galactic latitudes |b| >15 degr there are 3168 field galaxies (i.e. 42%) that
do not belong to pairs, groups or clusters in the Local universe. Applying to
this sample the percolation method with a radius of r_0=2.8 Mpc, we found 226
diffuse agglomerates with n>=4 number of members. The structures of eight most
populated objects among them (n>=25) are discussed. These non-virialized
agglomerates are characterized by a median dispersion of radial velocities of
about 170 km/s, the linear size of around 6 Mpc, integral K-band luminosity of
3*10^{11} L_sun, and a formal virial-mass-to-luminosity ratio of about 700
M_sun/L_sun. The mean density contrast for the considered agglomerates is only
<Delta n/\bar{n}\gtrsim 5, and their crossing time is about 30-40 Gyr.
