Smithsonian Astrophysical Observatory
Potential SAO Predoctoral Projects, 2004

Project Description

Project Title:
Quasar Winds
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 material.
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 atmosphere'.
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 medium.
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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