Investigation of the new Local Group galaxy VV 124 |
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Authors: | N A Tikhonov S N Fabrika O N Sholukhova A I Kopylov |
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Institution: | (1) Devon, UK; |
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Abstract: | We present the results of our stellar photometry and spectroscopy for the new Local Group galaxy VV124 (UGC4879) obtainedwith
the 6-m BTAtelescope. The presence of a fewbright supergiants in the galaxy indicates that the current star formation process
is weak. The apparent distribution of stars with different ages in VV 124 does not differ from the analogous distributions
of stars in irregular galaxies, but the ratio of the numbers of young and old stars indicates that VV 124 belongs to the rare
Irr/Sph type of galaxies. The old stars (red giants) form the most extended structure, a thick disk with an exponential decrease
in the star number density to the edge. Definitely, the young population unresolvable in images makes a great contribution
to the background emission from the central galactic regions. The presence of young stars is also confirmed by the OIII]
emission line visible in the spectra that belongs to extensive diffuse galactic regions. The mean radial velocity of several
components (two bright supergiants, the unresolvable stellar population, and the diffuse gas) is υ
h = −70 ± 15 km s−1 and the velocity with which VV 124 falls into the Local Group is υ
LG = −12 ± 15 km s−1. We confirm the distance to the galaxy (D = 1.1 ± 0.1 Mpc) and the metallicity of red giants (Fe/H] = −1.37) found by Kopylov et al. (2008). VV 124 is located on
the periphery of the Local Group approximately at the same distance from M31 and our Galaxy and is isolated from other galaxies.
The galaxy LeoA nearest to it is 0.5 Mpc away. |
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