Department of Physics, Engineering Physics & Astronomy

Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

Quasar Microlensing and the Nature of the Baryonic Dark Matter

Dr. Rudolph Schild
Harvard-Smithsonian Center for Astrophysics

Thursday, September 30, 2004
7:00 PM @ Stirling D

Abstract:

Since the original baryonic dark matter detection from quasar microlensing was first announced in 1996, substantial strides have been made in confirming the rapid microlensing signature in the Q0957 system and in other gravitational lens systems. The most rapid event recognized had 1% amplitude and 12-hour duration. Interpretation of the rapid fluctuations has centered upon three offered explanations: microlensing of fine quasar structure by a population of planetary-mass astronomical bodies in the lens galaxy; orbiting bright structures in the accretion disc of the supermassive black hole of the quasar; or dark clouds swarming around the luminous quasar source. The observations, particularly the equal positive and negative fluctuations, seem to strongly favor the cosmological population of planetary-mass objects in the lens galaxy. Of the several ideas advanced for the origin of such a population, the most appealing seems to be their birth at the time of recombination 300,000 years after the Big Bang.

Co-sponsored by the Department of Physics and the Department of Mathematics and Statistics. Refreshments will be available after the talk.