The Amateur Astronomers Association of Princeton is pleased to announce that monthly lectures are set to resume on Tuesday, September 8 at 7:30 p.m. in Peyton Hall on the Princeton University Campus.
This month’s speaker will be Dr. Paul J. Witta of the Department of Physics at The College of New Jersey. He will present a lecture entitled “Measuring and Modeling Variability in Quasars and Blazars.” Admission is free and the public is welcome. Ample free parking is available across the street from Peyton Hall.
Witta will talk about active galactic nuclei, including quasars, which are extraordinarily powerful, emitting up to thousands of times as much energy as all the stars in their host galaxies. A minority of them also eject relativistic jets of plasma that form giant radio lobes. All active galactic nuclei are characterized by variability and blazars exhibit the strongest fluctuations. This enhanced variability is due to Doppler boosting of the flux emitted by relativistic jets that point close to our line of sight. We have been measuring variability of quasars and blazars in the optical band from various ground-based telescopes for the past 20 years and have more recently employed the Kepler satellite as well as various X-ray telescopes to gather dense, uniformly spaced data. After setting the context, we will present some of these results, as well as our numerical simulations of variations of radio flux from the turbulent regions behind shocks in the jets.
Wiita received his PhD in Physics from Princeton in 1976 for producing the first numerical models of radio galaxies. He did post-docs at the Universities of Chicago and Cambridge. He was on the faculty at UPenn and Georgia State University and has been Chair of the Physics department at TCNJ since 2010. He has been a visiting professor at the Tata Institute for Fundamental Research, the Indian Institute of Astrophysics and Princeton. His research has mostly been in extragalactic astronomy, with a focus on radio loud active galaxies.
The Amateur Astronomers Association of Princeton is an organization of over 80 members with interest in all aspects of astronomy and space science. Founded in 1962, the AAAP promotes a wide range of astronomy-related activities including: solar, planetary and deep-sky observing, astrophotography, star parties, lectures and education. The group owns and operates two observatories in NJ at Washington Crossing State Park and Jenny Jump State Park. Members include avid observers, armchair investigators and complete novices. All share a common love of the sky.
Complete meeting details and directions are found at the AAAP web site princetonastronomy.org.
