Project Title: Models for Quasar Structure: Winds, Obscuring Tori
Project Advisor: Dr. Martin Elvis
Background: In the 40 years since quasars were
discovered, the paradigm of a supermassive black hole surrounded
by an accretion disk and emitting a relativistic jet has become
well supported and accepted. However, this paradigm deals
with a naked quasar. Instead the bulk of the >10(4) papers
written about quasars make no connection with this paradigm,
and deal with the gas surrounding the quasar: the broad and
narrow emission lines, and various UV and X-ray absorbing
Recently it has become clear that the missing '4th element' in
quasars, after the black hole/disk/jet trio, is a 'Quasar Wind'.
Several apparently separate components of the veil of gas surrounding
a quasar are part of a fast wind (1000-10,000 km/s) leaving the inner
regions of the quasar.
In 2000 I proposed a model in which ALL the atomic features are linked
in a single wind structure, so that they constitute the 'quasar
Quasar winds have implications for the inner workings of quasars, via
their accretion disks, and for how a quasar interacts with its
environment, both the host galaxy and the larger scale intergalactic
Scientific Questions: How can we tie down the properties
of this wind? Does it have hot and cold phases? Do the famous
broad emission lines of quasar also come from this wind? Are
the luminous quasar different from the weaker active galactic
nuclei, e.g. in having ultrafast winds (the `broad absorption
lines') or do viewing angles dominate?
Can we make models of how a wind is accelerated from the accretion
disk? How much do quasar winds pollute intergalactic space? Do quasar
winds make dust on their way out?
Scientific Methodology: All of these questions
can be addressed with specific observations and calculations.
Because they cover a wide area of methods [X-ray, UV, optical,
IR, mm, radio, modelling] please contact me to discuss specifics.
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