If dwarf galaxies are primeval objects in the universe, as hierarchical galaxy formation scenarios predict, they should show traces of their old stellar populations, perhaps distributed in extended, differentiated structures. The working hypothesis that such a structure could exist is tested for the case of DDO 187, a field, dwarf irregular galaxy

The solar rotation rate at latitudes 0 deg, 15 deg and 30 deg has been inferred by averaging the results of 120 regions of 15 degx15 deg, which have been studied over a total area of about 75 deg in latitude and 360 deg in longitude. A local helioseismology technique, the ring diagram analysis method, has been used to analyse the horizontal

Not Available

We have acquired narrowband imaging of NGC 2346 in the transitions H I λ6563 and λ4861 and [O III] λ5007. As a result, we are able to evaluate the variation of both excitation and extinction over the projected central parts of the nebular shell. Extinction appears to be surprisingly uniform, and there is (in particular) little evidence for the

We report new Hubble Space Telescope WFPC2 and NICMOS observations of the center of the nearest radio galaxy Centaurus A (NGC 5128) and discuss their implications for our understanding of the active nucleus and jet. We detect the active nucleus in the near-IR (K and H) and, for the first time, in the optical (I and V), deriving the spectral energy

Not Available