Colloquia

Seminars

• Astronomy and Space Physics
• Atomic, Molecular, and Optical Physics
• Condensed Matter
• Fluids and Plasmas
• Particle Physics
• Calendar of Events

Graduation Commencement

Astronomy & Space Physics Seminar Abstract

Date: March 4th (Conference Room 215, Sharp Lab, 4:00pm)

Speaker: Richard Ignace, Physics, Astronomy & Geology, East Tennesee State University

Title: Microlensing of Circumstellar Envelopes

Abstract:

Unlike gravitational lensing of distant quasars in which multiple  images
of quasars can be resolved separately, microlensing refers to the  limit
in which the multiple images are unresolved yet brightness variations
(sometimes substantial variations) are observable.  The lightcurve
that results depends on the source size in events for which the lens
trajectory transits or nearly transits the source.  Since source size
is usually a function of wavelength, there is an opportunity to map
the source with color as the event evolves, and in fact microlensing
has yielded data for atmospheric limb darkening in several sources.
I will discuss effects associated with using lensing as a tool for
studying circumstellar envelopes.  I will summarize work on modeling
observables for polarization, emission line profiles, and dusty winds
during microlensing events.  This year, there may be an opportunity
to measure for the first time the variable polarization arising from
microlensing using the RINGO polarimeter.