UCL Department of Physics and Astronomy

Prof Richard Ellis

Prof Richard Ellis

Professor of Astrophysics

Dept of Physics & Astronomy

Faculty of Maths & Physical Sciences

Joined UCL
1st Feb 2014

Research summary

My current research activities are focussed on my ERC Advanced Research Grant called First Light. First Light's principal goal is to examine the role that early galaxies played in driving cosmic reionisation. Please visit https://www.ucl.ac.uk/astrophysics/research/cosmology/first-light for more information.


I was an undergraduate at UCL and gained my BSc in Astronomy in 1971. For my DPhil in Astrophysics at Oxford, I undertook research in modelling stellar atmospheres to secure chemical abundances and did some experimental physics. I then moved to a teaching position at the University of Durham where I formed a new research effort in extragalactic astronomy and astronomical instrumentation taking advantage of the new opportunities available with the Anglo-Australian Telescope. I took leave for two years as a Principal Research Fellow at the Royal Greenwich Observatory to assist in the commissioning of the Isaac Newton and William Herschel telescopes on La Palma, returning to Durham as  Professor of Astronomy in 1985. After 19 years at Durham,  I moved to Cambridge as Plumian Professor in 1993 and served as Director of the Institute of Astronomy for 5 years. During this time, much of my research was undertaken with the Hubble Space Telescope as well as participating in the Supernova Cosmology Project whose team discovered the accelerating expansion of the Universe. In 1999, I emigrated to the USA to become the Steele Professor of Astronomy at the California Institute of Technology  and served as Director of the Palomar Observatory from 2000-2005. Access to the 10 metre Keck telescopes gave me the opportunity to examine the properties of the most distant galaxies known, often aided using the gravitational lensing provided by foreground clusters. After 16 years at Caltech, I returned to Europe in 2015 following the award of a ERC Advanced Research Grant held at UCL. I initially spent 2 years as Senior Scientist at the European Southern Observatory (ESO) headquarters in Garching, Germany, returning to UCL full time as Professor of Astrophysics in 2017.

During my career my research has moved from detailed studies of nearby stars, topics in Galactic structure and nearby galaxies to broader questions relating to the large scale structure of the Universe and its contents,  and the formation and evolution of galaxies.  My recent work addresses the origin of the earliest galaxies and understanding their role in cosmic reionisation. My programmes are primarily observational exploiting ESO’s  Very Large Telescope, the twin Keck telescopes and the Atacama Large Millimetre Array (ALMA).  I remain enthusiastic about the use of new instruments and observational opportunities when they further the progress that can be made in these areas. I am co-scientific lead for the Prime Focus Spectrograph, a highly- multiplexed instrument for the Subaru 8 metre telescope in Hawaii, and looking forward to the launch of the NASA James Webb Space Telescope.