Extended Red Emission: Photoluminescence by Interstellar Nanoparticles
Professor Adolf Witt
University of Toledo
4:15-5:15 Tuesday
March 4,
2003
Peyton Hall Auditorium
Abstract
Dust in nebulae, e.g. reflection nebulae, dark nebulae, planetary
nebulae, and HII-regions, as well as in the diffuse ISM of galaxies,
including the Milky Way Galaxy, contains a component that reveals its
presence by emitting visible light in the 500 - 1000 nm spectral range
in the form of a broad, unstructured emission band, referred to as
"Extended Red Emission (ERE). The strong correlation between the ERE
intensity and the local density of stellar UV photons over several
orders of magnitude suggests strongly that the ERE process involves
photoluminescence powered by UV photons, requiring sources with
T_{eff} > 10,000 K for excitation. In this talk, I summarize the
observational constraints that help define the nature and composition
of the ERE carrier.