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.
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