New dwarf galaxy candidates in the Leo-I Group |
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Authors: | I D Karachentsev V E Karachentseva |
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Institution: | (1) Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz, Karachai-Cherkessian Republic, 357147, Russia;(2) Astronomical Observatory, Kiev Taras Shevchenko National University, Observatorna str., Kiev, 304053, Ukraine |
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Abstract: | We have carried out a search for low-surface-brightness dwarf galaxies in the region of the Leo-I Group (M96) in images of the second Palomar Sky Survey. We found a total of 36 likely dwarf members of the group with typical magnitudes B t ~18m–19m in an area of sky covering 120 square degrees. Half of these galaxies are absent from known catalogs and lists of galaxies. The radial-velocity dispersion calculated for 19 galaxies is 130 km/s. The Leo-I Group has a mean distance from the Sun of 10.4 Mpc, a mean projected radius of 352 kpc, an integrated luminosity of 6.7 × 1010L⊙, a virial mass-to-luminosity ratio of 107 M⊙/L⊙, and a mean crossing time of 2.7 Gyr. The group shows evidence for a radial segregation of the galaxies according to morphological type and luminosity, suggesting that the group is in a state of dynamical relaxation. The subsystem of bright galaxies in the Leo-I Group is smaller in size (250 kpc) and has a lower velocity dispersion (92 km/s), resulting in a lower virial mass-to-luminosity ratio (34 M⊙/L⊙), as is typical of the Local Group and other nearby groups of galaxies. |
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