Staff at the AAO are actively involved in astronomical research and
in the development of new instruments to carry out these research projects.
Much of our rese arch concentrates on what is possible with the Anglo-Australian
Telescope (AAT) or the UK Schmidt Telescope (UKST). The AAO has a worldwide
reputation in both optical and infrared imaging and spectroscopy. A particular
feature of AAT and UKST research is large-scale surveys to identify hundreds
of thousands of a certain class of objects, in particular, old stars, galaxies
and quasars.
The AAO is the home base of two famous ongoing surveys: the Two Degree Field Galaxy Redshift Survey, and the Two Degree Field QSO Redshift Survey. The first of these is half way through obtaining redshifts (distances) to 250,000 galaxies out to a redshift of 0.3. The second survey aims to obtain redshifts for 50,000 quasars, most of these at redshifts between 1 and 2. But the AAO is involved in several other surveys, in particular a long-term survey to find planets around nearby stars. Several members of staff have also been actively involved in a worldwide programme to follow up gamma-ray burst events.
In addition to planets, old stars, galaxies and quasars, AAO astronomers have a wide range of other interests. These include the origin of life, brown dwarfs, supernovae, star formation, starburst and active galaxies, gravitational lensing and cosmology.
We are often asked ``What do we do?'' Contrary to popular opinion, we only use telescopes a few weeks a year. Getting time to use a telescope is highly competitive. At the last estimate, there are 13,000 astronomers worldwide although only about a third of these agressively pursue access to telescopes. AAO astronomers do not restrict themselves to the AAT or UKST. We apply for time on radio and sub-millimetre telescopes, and space-borne observatories like Hubble, Chandra and so on.
So just what do we do on a daily basis? Even a few nights of data can take many months or years to analyze. You will find most astronomers, like most professionals these days, sat in front of a computer either reading email (of course), playing with data, reading about new announcements or discoveries, accessing distant data bases over the internet, or building computer models to compare with their data.
The internet plays a key role in modern day astronomy. We have been
using some form of computer network since its inception at CERN in the
1970s. Today, data from most observatories can be accessed over internet.
Some observatories can even be operated via the internet. There exist vast
data bases which attempt to keep track of what is known about any given
direction on the sky, and about every object that was ever named by an
astronomer. Most of our journals are electronic so that you can download
any paper to your local printer. All of our applications for telescope
or satellite time are made via the internet.
So who are the AAO astronomers?
Synopsis
Russell Cannon (Emeritus)
Matthew Colless (PhD 1987; Cambridge)
Simon Ellis (PhD 2003; Birmingham)
Joss Hawthorn (PhD 1986; Sussex/RGO)
Roger Haynes (PhD1995; Durham)
Heath Jones (PhD 2000; ANU/RSAA)
Simon O'Toole (PhD 2003; Sydney)
Quentin Parker (PhD 1986; St.Andrews)
Stuart Ryder (PhD 1993; ANU/RSAA)
Will Saunders (PhD 1990; QMW, London)
Rob Sharp (PhD 2002; Cambridge)
Chris Tinney (PhD 1992; Caltech)
Fred Watson (PhD 1987; Edinburgh/ROE)
Here are our main areas of expertise arranged in order of scale, from
the small to the very large. You can download papers by AAO astronomers
by typing their last names into the ADS search engineor the LANL preprint
server. More details on the topics below
are given here.
Experimental
Chris Tinney, Simon O'Toole - planets, brown dwarfs, evolved stars
Russell Cannon - globular clusters, carbon stars
Quentin Parker, Fred Watson - Wide field astronomy, H-alpha surveys, Planetary Nebulae
Stuart Ryder - star formation in galaxies, supernovae
Joss Hawthorn - Galactic Halo, interstellar medium, galactic winds
Matthew Colless, Heath Jones, Rob Sharp, Simon Ellis, Will Saunders - galaxy clusters, large-scale structure, & cosmology
Some AAO staff live permanently near the telescopes at Siding Spring. These are highly skilled technicians widely recognized worldwide for their brilliant work and dedication. The AAO astronomers have responsibilities to instruments on the AAT or UKST as well, either in designing new machines or maintaining the present ones. Another aspect of our work is to assist visiting astronomers in the use of these instruments.
Several observatory staff are involved in the development of new instruments. There are opportunities to work on this development, in particular, optical or engineering design. Here are some of the experimental techniques for which the AAO is well known.
Astrometry - Chris Tinney
High resolution spectroscopy - Chris Tinney
Tunable imaging - Joss Hawthorn
Widefield imaging - Chris Tinney, Quentin Parker
Fibre spectroscopy - Sam Barden, Roger Haynes, Fred Watson, Will Saunders
The scientific method requires us to construct hypotheses which can
be tested against observations. We use the term astrophysics for
the process of building a physical model or theory to explain astronomical
observations. The development of theoretical models is fundamental to modern
day astronomy. In many instances, the observed phenomenon is far too complex.
There is increasing use of supercomputers. There are opportunities at the
AAO to carry out theoretical and computational astrophysics.
All of the above topics fall in the mainstream of modern astronomy and astrophysics. Bear in mind that many of these themes are potential PhD projects. Our vacation students often go on to pursue topics that were introduced to them at the AAO. We have also inaugurated a joint new AAO/Macquarie University honours scholarship programme which offers up to 2 annual $5000 scholarships to pursue jointly-supervised intrumentation projects at the AAO. For further details, application forms etc click HERE and follow the links to the scholarship page.
Since the discovery of planets around nearby stars, there has been a concerted effort to detect the planets directly. If an alien civilisation was to measure the radial velocity of our Sun to high precision, they would note a small oscillation with a period of 12 years due to the presence of Jupiter. Paul Butler, a past staff member of the AAO, has used this technique to find dozens of planets using high-resolution spectroscopy. This work is now being continued by Chris Tinney at the AAT in collaboration with Butler, now at DTM, Washington.
Chris Tinney, in collaboration with Tim Bedding of Sydney University, are using the radial velocity technique to find solar-like oscillations. These were first observed in the Sun by Douglas Gough of Cambridge University and are thought to be natural modes of oscillation driven by convective turbulence within the Sun. The study of these oscillations is known as asteroseismology and reveals details about the internal structure of stars.
Brown dwarfs are sometimes referred to as `failed stars'. Their masses
fall between Jupiter and low mass stars. It is still not clear if they
form like stars or like planets (by sweeping up material around a star).
Chris
Tinney is involved in several surveys to identify these mysterious
objects. At one time, it was thought they might make up a large fraction
of the missing mass in the universe although this now seems highly unlikely.
Since 1988, Joss Hawthorn and collaborators have been studying the energetic winds which occur at the centres of some galaxies. In some cases, these very powerful winds are produced by starbursts heating up the central volume to produce enormous pressures. But it is now clear that some of these winds are driven by the accretion disks which form around black holes. This year, with the Hubble Space Telescope and the Very Large Array radio interferometer, they find clear evidence that these winds develop much like the mushroom clouds of atomic bombs, entraining material from the atmosphere as they go.
There is no rigorous physical theory which takes us from the Big Bang to how galaxies formed. But we have a picture which places galaxy formation within a cosmological context. This is called the hierarchical cold dark matter (CDM) model. The basic picture is that the early universe produces a distribution of dark matter blobs, for want of a better word, often associated with cool hydrogen (+helium) gas. As time progressed, these clumps bang together to form bigger objects, and ultimately swarms of stars. You might well wonder what a `basic building block', a cosmic brick, is supposed to look like or whether we can ever expect to observe one. It has been suggested that some fraction of mysterious objects known as high-velocity clouds, seen in the radio spectrum at 21 cm, are associated with primordial building blocks. This is currently being investigated by Joss Hawthorn.
To get a handle on galaxy formation, we look into deep space when the
universe was young. But we can also look closer to home. The outer parts
of our Galaxy halo are known to be very old, although there is now evidence
for much younger systems as well. The CDM model predicts that the outer
parts of galaxies are still in formation, although at a much lower level.
Indeed, in 1995, a team using data from the UKST and AAT discovered a stellar
stream close to the Galaxy and on the far side from us. We now believe
the halo is full of such star streams. In other words, the larger part
of galaxies formed early on in the universe when there were many violent
interactions taking place. There is a nice analogy with the early Solar
System. We know from lunar craters that there were vastly more asteroids
and comets flying around the solar system when the planets first formed.
Of course, these unsettling objects are still out there but happily for
human life these are much rarer now. To put this into perspective, the
Solar system formed 4.73 billion years ago, as compared to the majority
of galaxy and quasar activity about 12 billion years ago.
The nature of dark matter remains one of the fundamental unknowns in astronomy. Joss Hawthorn make use independent methods to map out the shape of dark matter in galaxies and clusters. Globular clusters are like canaries in a coal mine. The way they move in the outer parts of galaxies tells us that dark matter must be there.
Large-scale redshift surveys of galaxies, clusters and quasars are key
areas of modern cosmology. The distribution of galaxies, whether in filaments
or on the surfaces of bubbles, are clues to what happened shortly after
the Big Bang. Likewise, the number and masses of clusters provide similar
clues, in particular, their distribution with redshift.
Matthew Colless,
Heath Jones,
Will Saunders and
Russell Cannon are actively involved in
redshift surveys.
So let me encourage you to apply for one of our studentships. You will find the AAO a very friendly and congenial environment. Students play a crucial role in research. We will give you an interesting and topical science project to carry out. Sometimes, this work is of sufficient quality that it leads to a published paper in a refereed journal.
We will encourage you to go on to a research career in astronomy. Most
of our past students do just that. One recent student now does theoretical
research with Neil Turok and Steven Hawking. Another recent student has
already established a reputation working on the microwave background, and
so on. In fact, many of the AAO staff have come through summer programmes
just like this one.
What makes someone a good astronomer? First, a good grasp of physics
and computers really helps, and of course mathematical modelling and analysis.
Second, a genuine love for astronomy and/or instrumentation helps too.
You will find most astronomers to be highly motivated and passionate about
their work. Modern astronomy draws on many sub-disciplines. Well
known astronomers were originally trained in fields as diverse as optics,
nuclear physics, low temperature physics, electrical engineering, chemistry,
biology, and even linguistics!
Another question were are frequently asked is
what is a `typical' career path in astronomical research. The PhD typically
lasts 4 to 5 years. After that, an astronomer looks to take one or two
postdoctoral positions each lasting 2 to 3 years. With luck, the astronomer
will then find a long-term or permanent position at an Observatory or on
the faculty of a University. You may need to wait a few decades for your
first Nobel prize.