Bibcode
Maiz-Apellaniz, J.; Mas-Hesse, J. M.; Munoz-Tunon, C.; Vilchez, J. M.; Castaneda, H. O.
Bibliographical reference
Astronomy and Astrophysics, v.329, p.409-430 (1998)
Advertised on:
1
1998
Journal
Citations
56
Refereed citations
53
Description
We have mapped spectrophotometrically the star--forming regions in the
center of the nearby SBm galaxy NGC 4214 with the aim of analyzing the
spatial distribution of some of its physical properties (density,
excitation, emission line intensity, extinction) and their relationship
with the distribution and evolutionary state of the stellar population.
Star formation takes place mainly in two big complexes, although several
smaller star--forming regions spread over the central bar of the galaxy
have also been identified. The comparison of different observable
parameters (W(Hβ ), Wolf-Rayet population, effective temperature,
UV absorption lines) with the predictions of synthesis models provides a
consistent picture in which the different star formation episodes took
all place around 3 Myr ago, with a very narrow spread in time (in any
case within 1 Myr). The brightest star forming complex, located at the
visible nucleus of the galaxy, is apparently the most evolved one. The
surrounding interstellar medium is being disrupted, with a clear spatial
decoupling between stars, gas and dust clouds. The dust appears
concentrated at the boundaries of the ionized region, affecting mainly
the nebular emission lines, while the stellar continuum itself is
located in a region relatively free of dust and gas. This decoupling may
explain the differences in extinction found previously between the
stellar continuum and the emission lines. On the other hand, the ionized
gas is essentially co-spatial with the massive stellar clusters in the
SE complex, which apparently is less evolved. Nevertheless, the dust
tends to be concentrated in isolated clouds located generally at the
boundaries of the line emitting nebulae. We postulate that stellar winds
have contributed to concentrate these dust particles in the
inter-cluster medium.