Adolf Witt (Astrophysics)

Distinguished University Professor of Astronomy
Ph.D., 1967, University of Chicago

Dr. Witt's interstellar matter research concentrates on the nature of interstellar dust and all those systems where interstellar dust assumes a central role. Observations made from both ground based observatories and from space with rocket and satellite instruments are used to determine the scattering properties of interstellar grains over a wide range of optical and ultraviolet wavelengths. Basic information related to the chemical composition and size distribution of the solid particles in space is obtained in this way. A major effort is now underway to use these results to interpret the effects of dust on the observable characteristics of entire galaxies.

In the course of these studies the distribution of interstellar material in our Galaxy and its effect upon the transfer of radiation through interstellar space is investigated. Situations of special interest occur whenever interstellar matter is swept up into clouds of relatively high density. If these clouds are associated with hot, luminous stars they will appear as emission and reflection nebulae in which scattered light can be observed with ease; Dr. Witt is actively engaged in the study of such objects.

More recently, he has become engaged in the study of near-infrared luminescence of solids in interstellar clouds. Spectroscopic observations of reflection nebulae and of planetary nebulae have yielded information pointing toward the widespread presence of silicon nanoparticles in interstellar space. The study of the spatial variability of the dust luminescence and its correlation with other environmental conditions related to the state of the gas in interstellar space is now producing valuable new insights into the interaction of gas and dust in space.

 Visit the Dusty Astrophysical Systems Group page to know more about the research conducted by Dr. Witt.

Selected Publications:

"The Photophysics of the Carrier of Extended Red Emission", T.L. Smith & A.N. Witt, Astrophysical Journal, 565, 304-318, 2002
"The Chemical Composition of the Interstellar Medium", A.N. Witt, Philosophical Transactions of the Royal Society of London Series A: Mathematical Physical and Engineering Sciences, 359:(1787) 1949-1958, 2001
"X-Ray Halos and Large Grains in the Diffuse Interstellar Medium", A.N. Witt, R.K. Smith & E. Dwek, Astrophysical Journal Letters, 550, L201-L205, 2001
"Multiple Scattering in Clumpy Media II: Galactic Environments", A.N. Witt & K.D. Gordon, Astrophysical Journal, 528, 799-816, 2000
"Silicon Nanoparticles: Source of Extended red Emission?", A.N. Witt, K.D. Gordon & D.G. Furton, Astrophysical Journal Letters, 501, L111-115, 1998
"Detection of Extended Red Emission in the Diffuse Interstellar Medium", K.D. Gordon & A.N. Witt, Astrophysical Journal, 498, 522-540, 1998