New Trends in Milky Way Research

Abstract

I feel honored indeed to have been asked to present the opening remarks at this beautifully planned Workshop on problems relating to the structure, kinematics and dynamics of the Milky Way System. These are exciting days for we have in recent years witnessed remarkable leaps forward in at least five areas of research relating to our Galaxy:

• (1) Evidence that our familiar Galaxy, with its central bulge, disk with spiral structure, and long-recognized modest halo is embedded in a huge outer halo or corona with a mass at least five times that estimated for our traditional Galaxy and a radius three or more times the traditional value.

• (2) Thanks mostly to advances in instrumentation in the near and far infrared, in radio astronomy, and in X-ray and Gamma-ray astronomy, we are constantly learning new facts about the central regions of our Galaxy, including the very center itself.

• (3) The recent CO radio-molecular studies are blowing new life into the study of the spiral structure of our Galaxy. This applies to spiral features in the inner parts (the beautiful results by Cohen et al. deserves special mention) and especially to features that are traceable in H I and in CO in the nearer parts of the outer halo or Corona.

• (4) The study of globular star clusters shows great promise for the future, but we must admit that the situation has become rather confusing. A few years ago it seemed as though real advances were being made in the study and interpretation of abundances of the elements from the spectra of stars in globular clusters, but today the whole story seems confused. We have made great advances in research on the dynamics of globular clusters, but much remains to be done on the dynamics of the globular cluster system, especially on the interpretation of the observed motions of the remote globular clusters that may define the outer rim of the outer halo or corona of our Galaxy.

• (5) One of the healthiest and most active fields for research on our Galaxy relates to star birth and early evolution. Here radio-molecular, near and far infrared work, and research based on observations in the old-fashioned optical region, are continuing to reveal new vistas. We seem to have succeeded pretty well in pinpointing the places in our Galaxy where the action lies.