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Дата изменения: Wed Jun 16 13:46:46 2004 Дата индексирования: Tue Oct 2 02:33:58 2012 Кодировка: Поисковые слова: iss |
| Search for the youngest galaxies and the problems of galaxy formation |
During 2 last years of work on the search for new galaxies in the
phase of first star formation (SF) burst there were carried
out spectral observations of 39 blue compact galaxies
(BCGs) - candidates to the most metal deficient unevolved
galaxies. 23 of them indeed have appeared new metal-poor
galaxies with the oxygen abundance (O/H) (as an indicator
of chemical evolution) less than 1/10 of the solar value.
Of them 12 are new BCGs with O/H less than 1/15 of solar
value. Thus, the number of these very rare galaxies
increased twice. Several of them can be good candidates to
young galaxies. The galaxy HS 0822+3542 is discovered with
O/H only 1/36 of solar value, the third one on metal
deficit among more than 1000 BCGs known. The two most metal-
deficient BCGs I Zw 18 and SBS 0335-052, with O/H ~1/56
and 1/41 respectively, are well known and carefully
studied. The new BCG is very interesting, on one hand, as
the most nearby (12 Mpc) of probable young galaxies,
and on the other hand, as the least massive of such galaxies. HS
0822+3542, being 60 times less massive than SBS 0335-052
fixes the large range of protogalaxy parameters, with which
retarded primeval galaxies can form on modern epoch.For 5
new galaxies the observations of HI in the line 21 cm were
carried out with 200-m Nancay radiotelescope (France). The
mass of HI in these galaxies is estimated. For the same
BCGs CCD-images in UBVRI were obtained to study their
morphology and color distribution. The latter allows to
determine the age of stars in various parts of galaxy and
check its suggested evolution status.
This work was carried out during 1997-1998 with financial support
from RFBR grant No. 97-02-16755
6-m telescope spectrum of one of new BCG HS 0837+4717 with metallicity Z = 1/20 Zo
The copy of this figure as a Postscript file
January 14, 1999 