In November 2007, I moved from the Australian Astronomical Observatory to take up a Federation Fellow Professorship at the Institute of Astronomy, School of Physics, University of Sydney. I am a Fellow of the Australian Academy of Science and the Optical Society of America. I am co-founder and associate director of the Institute of Photonics and Optical Science (IPOS) and an active member of the Sydney Institute for Astronomy (SIFA). I am a Visiting Professor of the Australia National University, Canberra and hold visiting positions with schools in France, Spain, UK and USA. For more background, see this December 2007 review in Gemini Focus or Profile of an Australian Astronomer under the web pages of the Astronomical Society of Australia. For media purposes, there is a high resolution portrait available here.
I supervise a group of Honours undergraduate students, MSc and PhD students, and Postdoctoral research fellows. About half work in astronomy and astrophysics and the others work on astrophotonics, space photonics and quantum astronomy experiments. The astrophotonics labs are based at the School of Physics on campus although a lot of shared activity takes place at Macquarie University and the Australian Astronomical Observatory. My group retains strong links with activities at the Leibniz Institute for Astrophysics, Potsdam; the Department of Astronomy, University of Maryland and NASA Goddard, and numerous other linkages across Asia and Europe. There are more than a dozen groups working on programs that started here at the University of Sydney. We launched our first balloon experiment in November 2012; this is to be followed by more balloons and a rocket launch. Our developments and patents are increasingly being exploited by medical and telecomm companies, remote sensing and food industries.
For web links to my research papers since 1984, astronomy papers are found here through ADS. Instrumentation papers are found here through SPIE. Optics papers are available here through www.opticsinfobase.org.
You may wish to see a review I wrote with Ken Freeman on "The Baryon Halo of the Milky Way" (Science, Jan 2000) or a related article in "Clues to Galaxy Formation" (Nature, July 1999). Both of these articles attempt to show that the time is ripe for a general convergence of far-field cosmology and near-field cosmology (cosmogony). This is a topic Ken Freeman and I explore in our 2002 Annual Reviews article and in our 2007 Saas Fee lectures. An updated and extended version of these lectures was published in 2013; we provide download details below.
First stars, first galaxies, dwarf galaxies. After an Aspen Winter School on Local Group Cosmology in Feb 2006, Jim Peebles and I wrote an update on this topic where we discuss the idea that the most ancient stars may be hiding near the Galactic Centre and therefore will be very challenging to identify. More recently, I have written a 2013 Reviews of Modern Physics article on the chemistry of the first stars with Torgny Karlsson and Volker Bromm. In collaboration with Ralph Sutherland, I am working on the evolution of dwarf galaxies in the Galactic halo and the formation of the first dwarf galaxies.
Million star surveys. Some of the most exciting developments are the huge stellar surveys under way in Australia, Europe and the USA. I am a co-founder of the RAVE survey at the UK Schmidt Telescope (Australia) which completed its last observations in early 2013. I am also a co-founder of the HERMES instrument and associated galactic archaeology survey (GALAH) which started in Feb 2014. The most anticipated of them all is the astonishing billion-star astrometric Gaia survey from ESA which launched successfully in Dec 2013.
Galaxia. A major development at the University of Sydney is the Galaxia code by Research Fellow Sanjib Sharma. This synthetic framework for the Galaxy has been used extensively to understand the Geneva-Copenhagen, Segue and RAVE stellar surveys. It allows for the different surveys to be cleaned up, to be intercompared and to be compared to a theoretical framework. Parameter estimation is possible through the use of two kinds of Markov Chain Monte Carlo (MCMC) techniques. The hierarchical and stochastic MCMC methods allow for fine (small errors, multiple solutions possible) and coarse (larger errors, full mapping of the parameter space) sampling respectively. The code also allows the stellar surveys to be compared to N-body simulations. To witness the power of this approach, see our recent study of 200,000 stars from the RAVE survey. We are now starting a full-blown study of the billions of stars within the 2MASS and APASS catalogues, and ultimately the Gaia catalogue (2019).
Disk galaxies. Here is a series of audio files where I describe recent work on the closest disk galaxy beyond the Local Group. In 2005-2011, we presented evidence in the Astrophysical Journal that the galaxy stellar disk extends twice as far as was previously believed. Moreover, the outer disk shows a peculiar trend in the stellar abundances. Using the Gemini South telescope, we reach equivalent surface brightness levels that have never been achieved before. The full news story is available at this site.
Galactic Centre explosion. In 2003, Martin Cohen and I discovered a large-scale wind from the Galactic Centre. This preempted the marvellous Fermi discovery of the gamma-ray bubbles in 2010 over the same physical scale (+/-50 degrees!). At the time, we were unclear whether the explosion was driven by a starburst or by a supermassive black hole. But in 2013, we discovered that the Galaxy underwent a full-blown Seyfert phase just two million years ago, i.e. when Homo Erectus walked the Earth! This means that the well-established supermassive black hole at the Galactic Centre (Sgr A*) was blasting bipolar jets at full power only recently in cosmic terms. Of course it's the accretion disk that swirls around the black hole that does this, not the black hole itself. This story had major press coverage in September 2013. The best description of the work is the New Scientist feature article. A link to my TV interview is given below.
Gas accretion onto galaxies. A great deal of my work has focussed on how gas gets into galaxies. Our large Hubble Space Telescope programme (Fox et al 2013, 2014) targets 70 quasars seen through the Magellanic Stream. These background sources allow us to see the imprint of a rich forest of UV absorption lines across the Galactic halo. We have begun to probe the Galactic wind region using the same method.
The astrophotonics labs have completed or are developing a range of novel astronomical instruments: SAMI, Hector, HERMES, GNOSIS, PRAXIS, MOHSIS, PANDORA, Dragonfly, nanoSPEC, i-INSPIRE and PIMMS.
My own interest in photonics (which includes optoelectronics) started in 2000 when talking to Martin Harwit about the prospects of improved space communications. We were struck by how little potential data from space missions was getting back to Earth, even allowing for data compression. In 2002, I wrote two papers on "Laser Telemetry from Space" with father and son team, Martin & Alex Harwit (Science, July 2002). The papers were adopted as a NASA white paper in that same year and a workshop was held at JPL to discuss the work. My team at the AAO formed the Centre for Space Photonics to pursue funding avenues. This led to a second NASA visit to Australia to attend the IAU 2003 where a special session was held on laser communications. In early 2006, and sooner than I had ever anticipated, a NASA Goddard team achieved the first interplanetary laser communications over a distance of 24 million km (Science, Jan 2006). With specific reference to our work, their paper describes how they used the MESSENGER satellite which is on a 6.6 year voyage to Mercury and due to arrive in early 2011. For more information, see our laser communications website.
Since 2001, my group has explored the use of photonics in astronomical and space instrumentation -- a field now known as astrophotonics. Most papers can be accessed through opticsinfobase. Optics Express highlighted the field of astrophotonics in a special issue (12 papers) in Feb 2009; astrophotonics and space photonics were also featured in 2012 Physics Today article. The field has received special sessions at EOS (Europe) and OSA (USA) optics conferences. Some of our new technologies were tested on our first balloon experiment in November 2012; this is to be followed by more balloons and a rocket launch.
The field of quantum optics is finding increasing relevance and overlap with astronomy. The field originally grew out of Hanbury Brown's astronomical projects (Sydney, Manchester) in the 1950s and 1960s. In this respect, quantum astronomy has been with us for a long time although little has happened since the early analogue experiments. In recent years, there has been a steady rise in quantum astronomy in large part due to the prospect of single photon detection at picosecond rates (SPADs, SiPMs) and the promise of AO-assisted extremely large telescopes. At Sydney and Macquarie, we have begun to investigate photon orbital angular momentum and related phenomena.