Colloq Abstract - Richards
Nov 17
11:00am Mountain
Gordon Richards (Drexel)
A Modern View of Quasars
Abstract
I will contrast a view of quasars as diverse *processes* with their
traditional view as more static *things*. Such a picture is important
both to understanding quasars themselves and also the role that they
play in the evolution of galaxies. Understanding the relative rarity
of radio emission in luminous quasars is crucial to understanding
their evolution. We find that analysis of emission and absorption
line properties of quasars provides revealing insights into the their
radio properties. In particular, we find that there is no such thing
as a "typical" radio-quiet quasar with which to compare radio-loud
quasars. Instead it appears that quasars span a broad range of
properties from soft-spectrum objects which host radiation-line-driven
outflows to hard-spectrum objects which are (sometimes) the
progenitors of radio-loud quasars. Using a combination of emission,
absorption, and both radio and optical continuum data is crucial for
understanding whether the origin of radio emission in luminous quasars
is due to black hole spin, star formation, shocks from winds, magnetic
fields, or a combination thereof. I won't answer this question;
instead I seek your help in understanding the feasibility of our
picture.
