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оригинального документа
: http://www.sao.ru/Doc-en/SciNews/2011/Makarovy/
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The study of star formation in KDG61 and KDG64 based on spectroscopy
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Russian version |
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The history of star formation was successfully analyzed for the first
time based on the spectra of the stellar population of dwarf galaxies
of low surface brightness outside the Local Group.
We have investigated the stellar population of two dwarf spheroidal
galaxies KDG61 and KDG64 in the central part of a close group of
galaxies M81.
The integral spectra were obtained on the 6-m BTA telescope. Direct
imaging performed on the Hubble Space Telescope (HST /ACS) was as well
used for the quantitative analysis of the history of star formation.
Both approaches have yielded consistent results. These galaxies are
dominated by the old stellar population (12-14 billion years) of
low metallicity ([Fe/H] ~ -1.5). Both galaxies reveal stars aged
from 1 to 4 billion years.
This population demonstrates a slight enrichment of metals. No significant
radial gradient in age or metallicity was observed in the resolved
stellar population.
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Fig.1. KDG61 
Fig.2. KDG64 |