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arXiv · 1210.6571

Low Density Structures in the Local Universe. I. Diffuse Agglomerates of Galaxies

I. D. Karachentsev·V. E. Karachentseva·O. V. Melnyk·A. A. Elyiv·D. I. Makarov
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Abstract

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.

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I. D. Karachentsev, V. E. Karachentseva, O. V. Melnyk, A. A. Elyiv, D. I. Makarov. 2012-10-24. Low Density Structures in the Local Universe. I. Diffuse Agglomerates of Galaxies. https://doi.org/10.1134/s1990341312040013

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