Professor Richard Ellis' Homepage

Professor Richard Ellis

Position: Plumian Professor
Telephone: +44-1223-330879
Fax: +44-1223-335723
Email: rse@ast.cam.ac.uk

Overview of Research

I am working primarily in observational cosmology addressing issues related to the nature of the world model, the origin and evolution of galaxies, the growth of large scale structure and the nature and distribution of dark matter. I am enthusiastic about the use of new instruments and observational opportunities when they further the progress that can be made in these areas.

Research Programmes

I am currently involved in several long-term programmes which are listed below:

2dF galaxy redshift survey: this is an approved survey of over 250,000 galaxies using the wide field multi-fibre system now in operation at the AAT. Primary aims are to measure the distribution of galaxies on very large scales, to constrain the growth in clustering with redshift, to measure redshift space distortions and to investigate the connection between bias, mean mass density and luminosity. A team of 20 astronomers in UK and Australia have joined forces to conduct this survey which is now the largest systematic redshift survey (see latest map of the galaxy distribution )

In March 1998 I organised a meeting on Large Scale Structure which was held in the Royal Society, London . It provided an opportunity to discuss results from 2dF and other projects. The proceedings have appeared in Phil. Trans. (see Cambridge on-line version )
Berkeley-Cambridge distant supernovae project: this is an ongoing project to find and monitor distant supernovae (SNe) of Type Ia and, assuming their peak luminosities can be determined in a consistent manner, estimate the cosmological deceleration and the rate of supernovae as a function of type and redshift. A particularly important goal is to eliminate or otherwise models with a non-zero cosmological constant. HST is being used to track the most distant SNe (so far up to z=1.2) and provide morphological types for the host galaxies. The most recent article on this project discusses constraints from 42 distant supernovae and provides tantalising evidence for a non-zero cosmological constant.
Resolved studies of distant galaxies: This is a large HST-based programme to understand the origin of the faint blue galaxy problem and to place new constraints on the luminosity and structural evolution of regular massive spirals and field ellipticals. The datasets being analysed comprise (i) multicolour HST images of over 300 galaxies with redshifts and infrared photometry drawn from the CFRS/LDSS surveys and other archival fields, and (ii) deeper data of the Hubble deep fields North and South. Plans are underway to conduct integral field spectroscopy of selected sources from these catalogues.
Recent results on the declining number of galaxies with irregular morphology and the slow growth of disk galaxies have appeared in Ap.J. Further work on the assembly history of field ellipticals and origin of bulges and bars is appearing shortly.
Gravitational lensing: I coordinate a European collaboration under the auspices of European Union TMR network which aims to exploit HST optical and infrared images and ground-based spectroscopy for addressing the nature of faint galaxies and the distribution of dark matter on various scales from precise mass modelling.
The above programmes are being augmented by new instrument developments recently completed at Cambridge. These include a panoramic near-IR 4 x 1024 x 1024 HgCdTe camera successfully commissioned at La Palma and now executing a major survey at Las Campanas in association with Carnegie Observatories , and a near-IR OH suppressed spectrograph which offers both multi-object and integral field capabilities which is being developed as a fast-track instrument for Gemini . These instruments are aimed at exploring the clustering, star formation characteristics and evolutionary behaviour of galaxies within the important era 1 < z < 2.5 where relatively little data is currently available.

Current Committees

Space Telescope Science Institute Council
UV-Optical-IR Astronomy from Space Subcommittee of US National Academy of Sciences `Decade' Survey
IUCAA Science Advisory Committee
PPARC Science Committee
VISTA Executive Board
NGST Science Working Group (UK)