|
|
The Question
(Submitted April 09, 1997)
I'm a student of physics from Canada, and I was wondering how I could find out
about quasars on a very detailed level.
The Answer
Since you know about black holes, I assume you know that quasars are a
subset of a class of galaxies called active galactic nuclei (AGN) that
are probably powered by a supermassive black hole. If you haven't
already, check out "Active Galaxies" under "Advance High-Energy
Astrophysics" at our Learning Center. If you are mostly interested in
the physics of accretion onto a black hole, the standard text is
"Accretion Processes in Astrophysics" by Frank, King and Raine.
On the other hand, if you are more interested in AGN in general, the
basic textbook is "The Astrophysics of Gaseous Nebulae and Active
Galactic Nuclei" by Osterbrock (the emphasis here is on optical spectra
but it contains a lot of the physics of photoionzation which is
important in AGN).
Quasars are AGN that are very luminous and radio-bright, and we think
that in general they are radio-bright because we are seeing synchrotron
emission from a jet of relativistic particles coming from the AGN. In
radio-quiet AGN, either the jet is not present or it is directed away
from us (since the particles are relativistic, the emission is beamed
along the direction of the jet). There are some nearby radio galaxies
that may be low-luminosity descendents of quasars, that show radio jets
and evidence of many high energy particles (see books below). Blazars
are an extreme case of quasars where we think we are looking directly
into the jet.
A couple of books and articles on Radio Galaxies and Jets are:
Chapter 13 of "Galactic and Extragalactic Radio Astronomy",
edited by G.L. Vershuur and K.I. Kellermann, 1988, Springer-Verlag.
"Beams and Jets in Astrophysics", by P.A. Hughes,
c. 1991 Cambridge University Press
"Extragalactic Radio Jets" in Ann. Reviews of Astrophysics, 1984, 22:319-58
by A.H. Bridle and R.A. Perley
Sincerely,
Andy Ptak and Jonathan Keohane
-- for Imagine the Universe!
|
