A detailed insight into the star formation history of a sample of HII galaxies has been obtained, based on radio continuum and optical broad band and narrow band observations. HII galaxies are dwarf galaxies whose optical spectrum resembles that of HII regions, many of which are also known as Blue Compact Dwarf Galaxies. VLA observations at several

The discovery of a very high velocity, low-intensity gas feature in the giant extragalactic H II region NGC 5471 is reported. A broad component in the emission lines of H-alpha + forbidden N II 6548, 6584 A is located within an area less than 1 arcsec in diameter at the position known as knot C. The broad component is characterized by its low

We define a method for the analysis of the integrated spectra of extragalactic globular clusters that provides more reliable measures of the age, metallicity and α-element abundance ratio than have so far been achieved. The method involves the simultaneous fitting of up to 25 Lick indices in a χ2 fitting technique that maximizes the use of the

In an effort to test stellar structure and evolution models, analysis of oscillations in A and F stars in open clusters is carried out by the STACC network (Frandsen cite{stacc}). In this paper we describe our effort to locate a suitable open cluster in the northern hemisphere for a future multi-site campaign. We present BV Johnson and time series

One of the classical tests of the early dynamical evolution of the Milky Way is the prediction of the monolithic collapse model (e.g., Eggen, Lynden-Bell, & Sandage 1962) of a decline in the mean stellar abundance of the halo population as one proceeds to stars at greater distances, or equivalently, with higher local space velocities in the solar

Aims.We present a study of the neutron star X-Ray Transient Cen X-4. Our aim is to look for any evidence of irradiation of the companion with a detailed analysis of its radial velocity curve, relative contribution of the donor star and Doppler tomography of the main emission lines. Methods: .To improve our study all our data are compared with a set