Astronomy Colloquium

Neugebauer Lecture

In 1964 I started working as a Caltech Graduate Student with Gerry Neugebauer and Bob Leighton on the 2.2-micron Sky Survey at Mount Wilson. This led to the first detection of infrared radiation from the very center of the Milky Way Galaxy in 1966, centered on the radio source Sgr A. I will tell the story of that first discovery and follow up that occurred in the 1970 and 1980's at The Palomar 200 inch telescope, Mount Wilson telescopes , Mauna Kea Hawaii telescopes and especially on the KAO flying 0.9 meter telescope. This included both measurement of stars and dust in the region centered near SgrA* the newly discovered radio point source. The most interesting KAO observation led to the discovery of a ring of dust around Sgr A* (work with Mike Werner and Ian Gatley). In 1995, Andrea Ghez, Mark Morris and I started looking for evidence of a possible massive Black Hole in the Galactic Center using proper motion of stars. Spectacular observations using the Keck 10-meter telescopes with large format near-infrared arrays and adaptive optics led to the confirmation of the presence of such a black hole and an estimate of its mass (4xE6 M (Sun)). Mark, Andrea and I with the key additions of Leo Meyer, Gunther Witzel and others also began multi-wavelength observations of the variable source associated with SgrA* using Keck and Spitzer. I will discuss briefly these fabulous results. I will finish my talk by discussing SOFIA (2.5 Meter flying telescope) observations of the ring of dust and gas orbiting the massive black hole in the center of our Galaxy.

To view this talk via YouTube, please visit https://www.youtube.com/playlist?list=PLb1880Rn0qkKzIavl-n_7RaMyDOiU9XHm