* Astronomy

Title: Nearby groups of galaxies in the Hercules-Bootes constellations
Author: Igor D. Karachentsev, Olga G. Kashibadze, Valentina E. Karachentseva

We consider a sample of 412 galaxies with radial velocities VLG<2500km s^-1 situated in the sky region of RA=13h.0 ... 19h.0, Dec=+10°... +40° between the Local Void and the Supergalactic plane. One hundred and eighty-one of them have individual distance estimates. Peculiar velocities of the galaxies as a function of Supergalactic latitude SGB show signs of Virgocentric infall at SGB<10° and motion from the Local Void at SGB>60°. A half of the Hercules-Bootes galaxies belong to 17 groups and 29 pairs, with the richest group around NGC5353. A typical group is characterized by the velocity dispersion of 67 km s^-1, the harmonic radius of 182 kpc, the stellar mass of 4.3 x 10^10 solar masses and the virial-to-stellar mass ratio of 32. The binary galaxies have the mean radial velocity difference of 37 km s^-1, the projected separation of 96 kpc, the mean integral stellar mass of 2.6 x 10^9 solar masses and the mean virial-to-stellar mass ratio of about 8. The total dark-matter-to-stellar mass ratio in the considered sky region amounts to 37 being almost the same as that in the Local Volume.

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