We present a study of the grand-design spiral galaxy NGC 5248 (Jogee et al. 2002a,b) based on a combination of multi-wavelength % optical, near-infrared, and CO (J=1--O) observations and hydrodynamical modeling.

We derived photospheric parameters, mass-loss rates, and wind velocities of Galactic O6-O7 stars by analyzing high-resolution spectra in the far-UV and UV ranges with line-blanketed, hydrodynamic, non-LTE spherical models. We combined spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE) in the range 905-1187 Å and International

We have studied the effect of the mass of the central star (CS) on the gas evolution during the planetary nebula (PN) phase. We have performed numerical simulations of PN formation using CS tracks for six stellar core masses corresponding to initial masses from 1 to 5 Msolar. The gas structure resulting from the previous asymptotic giant branch

A further fundamental modification needs to be made to the Freeman (1970) law, such that not only do LSB galaxies possess fainter central surface brightnesses than the canonical Freeman value, but the upper limit is in fact an upper (bright) `envelope' of points in the central disk surface-brightness - log(scale-length) diagram, with slope ~2.

The Century Survey is a photometric survey strip from which we select blue stars to probe the Milky Way halo. We obtain S/N=30 spectra for every star with (V-R)

We present extensive new spectroscopy and imaging of PNG 135.9+55.9. We use these data as constraints to photoionization models to derive limits on the oxygen abundance. We find that PNG 135.9+55.9 has an oxygen abundance less than 1/50 of the solar value. Our models favour a value of 12 + log O/H between 5.8 and 6.5 dex, confirming that PNG 135.9