The investigation of the Galactic nucleus and its surroundings is necessarily a modem endeavor, for traditional observations made at visual wavelengths have not even begun to penetrate the veil of -30 magnitudes of visual extinction that intercedes. On the other hand, infrared, and especially radio observers find a relatively unobstructed view of the central portion of the Galaxy, so the study of this arena has proceeded apace with the development of these branches of astronomy. Thus, it is no accident that the first IAU sponsored conference to be held on the Galactic center is timed to coincide with the initiation, or the immediate aftennath, of major technical developments at long wavelengths, including infrared array detectors, millimeter-wavelength aperture synthesis, and self-calibration and refmed deconvolution algorithms in aperture synthesis radio astronomy. The center of the Galaxy is also accessible to X and gamma-ray observers, and progress at high energies has been steady, especially as imaging capabilities are being realized at X-ray wavelengths. However, one might expect that the revolution in the high energy domain is still ahead of us, as instruments with larger collecting areas and improved spatial resolution are now being developed. The youth of this subject is evidenced by the relatively small number of meetings that have been devoted to it.

Klappentext

Proceedings of the 136th Symposium of the International Astronomical Union, held in Los Angeles, USA, July 25-29, 1988

Inhalt
Perspectives.- The Galactic Center: Outstanding Puzzles and Challenges (Introductory Review).- Galactic Centers Ours and Other Galaxies'(Review).- The Distance to the Galactic Center: R0 (Review).- Proper Motions of H2O Masers in W49(N) and the Distance to the Galactic Center.- OH-IR Sources and the Galactic Centre Distance.- The Galactic Bulge.- Characteristics and Space Distribution of Stars in the Bulge of the Milky Way (Review).- Evidence against Formation of the Stellar Bulge by Mergers Taking Place over a Hubble Time.- The Nature of The Carbon Stars in The Galactic Bulge.- The Distribution of Stars Within 2° of The Galactic Centre Revealed by 1 to 2 ?m Images.- The Large-Scale Interstellar Medium.- Non-Circular Gas Motions in the Inner Galaxy (Review).- Gas and Dust in the Inner Few Degrees of the Galaxy(Review).- Abundances in the Galactic Center.- IRAS Observations of the Galactic Center.- Molecular Line Observations of the Galactic Center Region.- Molecular Clouds in the Central 100-pc of the Galactic Center.- OH in the Galactic Centre.- Observation of Diffuse CII Emission in the Galactic Center Region.- 158 ?m [CII] Mapping of the Galactic Center Molecular Clouds.- Wide-Line Molecular Clouds and the Gamma-Ray Deficit Toward the Galactic Center.- A Survey of Radio Recombination Line Emission From the Galactic Center Region.- On The Evolution of Accretion Disks in Galactic Centers.- On Heating, Ionization, and Star Formation in the Galactic Center Region.- Observations of Discrete Sources.- Detection of the 20?3-1 Transition of 13CH3OH.- Distribution of the H2O Masers in the Sagittarius B2 Core.- A Possible Molecular Counterpart to the G359.54+0.18 Non-Thermal Filaments.- Bright Near-Infrared Sources Within 1° of the Galactic Center.- G359.30.82:An Unusual Radio Source.- VLA Observations of Far-IR Sources Toward the Galactic Center.- Ejection Structures.- Large Scale Ejection Structures in the Galactic Center (Review).- Galactic Center Jet of 4-kpc Length.- Symmetrical Structures in the Galactic Centre Region.- The Arc.- Filamentary Structures Near the Galactic Center.- Observations of Linear Polarization at 32 GHz of the Galactic Center Arc.- VLA Polarization Observation of the Radio Arc at 15 GHz.- Unusually Wide, High-Velocity Radio Recombination Lines from GO.150.05 in the Radio Arc.- An IR Quintuplet Near the Galactic Center.- Mid-Infrared Observations of the Galactic Center Arc and the Sgr A East HII Region.- HI Absorption Measurements over the Galactic Centre Radio Arc and Arches Regions.- Magnetic Phenomena.- MHD Aspects of Galactic Center Physics (Review).- MHD Mechanisms for the Formation of Galactic Center Lobes.- On The Galactic Dynamo.- Electrodynamics at Galactic Center.- The Strong Magnetic Field Galactic Center-AGN-Quasar Model.- Gas Dynamics in the Galactic Centre: Gravity vs. Magnetism.- The Environment of the Sgr A Comple.- The Nature, Location and Environment of Sgr A East (Review).- Continuum Observations of Sgr A at mm/submm Wavelengths.- A Large Near-Infrared Image of the Galactic Center.- HI Absorption Against the 40 km s-1 Cloud and the Circumnuclear Disk in Sgr A.- NH3 Observations of the Sgr A Complex Region with the Nobeyama Millimeter Array.- Gas Feeding Toward the Central Neutral Ring in the Galactic Center.- Shocked Molecular Gas Near the Galactic Center.- H76? Emission from the Sgr A 15 km s-1 Cloud.- Sagittarius A West and the Circumnuclear Disk.- The Circumnuclear Disk (Review).- Hat Creek HCO+ and HCN Observations of Sgr A.- Fabry-Perot Images of Ionized and MolecularHydrogen in Sgr A.- CS Multitransition Observations of the Circumnuclear Disk.- OH in the Environment of Sgr A.- The Luminosity of the Central Parsec of the Galaxy (Review).- The Kinematics of the Ionized Filaments in Sgr A West (Review).- Multi-Array ?2 and 6cm Radio Continuum Observations of Sgr A West.- High Quality VLA Imaging of Sgr A West at 6 cm.- Magnetized Structures in Sgr A West (Review).- High Resolution 11.6 ?m Images of the Central 1 Parsec of the Galactic Center With a New 58 × 62 Si:Ga Array Camera..- CO Along the Line of Sight to Galactic Center Infrared Sources.- Comment on the Standard of Rest Associated With the Neutral Ring at the Centre of the Galaxy.- Stars and the Central Mass Distribution.- The Stellar Cluster (Review).- A Search for Variable Stars at the Galactic Center.- The Mass Distribution in the Central Few Parsecs of the Galaxy (Review).- The Mass Distribution in the Galactic Center.- The Mass Distribution in the Galactic Centre Estimated from OH/IR Stars.- The Compact Central Objects.- High Resolution Near-Infrared Imaging and Computer Simulations of a Lunar Occultation of the Galactic Center.- The Stars That Power the Galactic Centre.- Velocity-Resolved Spectra of Br-? and Br-? on IRS16 SW and NE.- Observations of HI Br- ?, [Ne II], and [Ar III] from the Central Parsec of the Galaxy.- High Velocity Ionized Gas near 1RS 16.- The Compact Nonthermal Radio Source at the Galactic Center: an Update (Review).- Long-Term Variations of the Compact Radio Source Sgr A* at the Galactic Center.- Considerations of a Massive Black Hole.- Manifestations of a Massive Black Hole in the Galactic Center.- Constraints on and Alternatives to a Massive Black Hole at the Galactic Center (Review).- The High-Energy View.- X-Ray Observations of theGalactic Centre (Review).- Gamma-Ray Imaging of the Galactic Center Region.- Annihilation Radiation and Gamma-Ray Continuum from the Galactic Center Region (Review).- A Search for Radio Recombination Lines of Positronium Near the Galactic Center.- MeV Gamma Ray Observational Constraints on the Galactic Center Region.- Low Energy Galactic Center Gamma Rays from Low Mass X-Ray Binaries.- Mapping the Galactic Center Region with GRASP.- Study of the Galactic Center with a High Resolution Gamma Ray Telescope.- Conference Summaries.- Observational Perspective.- Theoretical Perspective.- Author Index.- Source Index.