Issue |
Astron. Astrophys. Suppl. Ser.
Volume 134, Number 1, January I 1999
|
|
---|---|---|
Page(s) | 21 - 37 | |
DOI | https://doi.org/10.1051/aas:1999435 | |
Published online | 15 January 1999 |
The Local Group dwarf irregular galaxy IC 1613
I. The young stellar content
1
Instituto de Astronomía, Universidad Nacional Autónoma de México, México
2
Institute of Astronomy, Bulgarian Academy of Sciences, 72 Tsarigradsko chaussèe, BG – 1784 Sofia, Bulgaria
3
Department of Astronomy, Sofia University, BG – 1164 Sofia, Bulgaria
Send offprint request to: J. Borissova
Received:
26
March
1998
Accepted:
1
July
1998
We obtained U-band photometry of 1500 stars and BV-band photometry
of 3100 stars in a field centred on the HII regions of the northeast sector of
the dwarf irregular galaxy IC 1613 – a member of the Local Group. The ages of
the stellar populations were determined from the
color-magnitude using the isochrones from Padua's library. The stellar populations were
split into three groups: the group of the youngest stars with ages of between 5
and 20 Myr, the group of intermediate stars with ages of 200-300 Myr and the
group of old stars with ages up to 10 Gyr.
The slope of the Stellar Initial Mass Function (IMF) for blue stars
is
which is
similar to that of other nearby galaxies. We investigated the stellar
content of nine Hodge associations as well as that of seven new OB associations
determined by cluster analysis. The total U, B and V magnitudes of eight
Hodge open clusters and two new cluster candidates are given and there are
six new possible nonstellar objects reported. The latter are most probably
distant galaxies visible through the disk of IC 1613, which confirms the
original suggestion of Baade that IC 1613 contains no bright globular
clusters.
Key words: galaxies: individual: IC 1613 / galaxies: stellar content / galaxies: star clusters and associations
© European Southern Observatory (ESO), 1999