Research

The main focus of my current research is in the study of galaxy formation and evolution in the Epoch of Reionization; focusing on the discovery of high redshift galaxies and quasars powered by the accretion of matter onto supermassive black holes. I work on the discovery of quasars and active galaxies that host supermassive black holes, the determination of the space densities, star formation rates and how and when galaxies and quasars form. In the past I have worked on the experimental determination of the rate of gravitational deceleration of the Universe. This work resulted in the unexpected discovery that the expansion of the Universe is accelerating.

I am a founding member of the Supernova Cosmology Project (SCP) team that discovered the accelerating expansion of the Universe through observations of distant supernovae.  The team leader Saul Perlmutter was awarded the 2011 Nobel Prize in Physics for this discovery. I was awarded the 2015 Breakthrough Prizes In Fundamental Physics and the 2007 Gruber Prize in Cosmology for the discovery of the accelerating Universe shared with members of the Supernova Cosmology Project.

My research also includes developing experimental survey techniques for discovering new high redshift quasars and using quasars to probe the baryonic content of the Universe. My collaborators and I  pioneered the use of high redshift quasars to determine the mass of neutral hydrogen in the high redshift Universe via intervening absorption lines imprinted on the spectra of background high redshift quasars. I have also pioneered the use of mm and submm microwave radiation to determine the star formation rate in quasar host galaxies.

I am the Principal Investigator (PI) of the ambitious VISTA Hemisphere Survey(VHS) which is a new near Infra-Red sky survey project which started in April, 2010.  The has been been awarded 300+ clear nights over a 5 year period on the new 4.2m ESO VISTA telescope in Chile. I lead the quasar science working group in the Dark Energy Survey(DES) project which built  a very large CCD camera (DECAM) and has been awarded 500 nights on US CTIO 4m telescope in Chile to use this camera  to observe in the optical the VHS region of the sky.

The exploitation of the extremely large datasets from these new surveys requires the use and development of robust data-mining techniques for distributed databases; machine-learning techniques such as decision trees, supervised learning and multi-dimensional data visualisation techniques.

• A week in Stockholm as a member of the Supernova Cosmology project (SCP) for the 2011 Nobel Prize awards
• Dawn after the dark age; Nature News and Views)
• Microsoft Technology, Researchers to Harness Galaxies of Data

 

Selected papers

Google Scholar page

• Gravitationally lensed quasars in Gaia: I. Resolving small-separation lenses, Lemon, Auger, McMahon, Koposov, 2017, MNRAS, 472, 5023
• Heavily reddened quasars at z~2 in the UKIDSS Large Area Survey: a transitional phase in AGN evolution, Banerji, M., McMahon, R.G. et al, 2012, MNRAS ,427, 2275
• A luminous quasar at a redshift of z = 7.085, Mortlock, D et al., 2011, Nature, 474, 616
• The discovery of the first luminous z ~ 6 quasar in the UKIDSS Large Area Survey; Venemans, B., McMahon R.G. et al, 2007, MNRAS, 376L, 76; 
• DAzLE: the dark ages z (redshift) Lyman-α Explorer; Horton et al., 2004, SPIE,5492, 1022.
• The evolution of Ω_HI and the epoch of formation of damped Lyman α absorbers, Peroux, C. McMahon R.G. et al, 2003, MNRAS, 346L, 1103.
• Lyman break galaxies and the star formation rate of the Universe at z~ 6; Stanway, Elizabeth R.; Bunker, Andrew J.; McMahon, Richard G., 2003, MNRAS, 342, 439: 
• The far-infrared-submillimetre spectral energy distribution of high-redshift quasars, Priddey, R. and McMahon, R.G., 2001, MNRAS, 324P, 17.
• Optical Counterparts for 70,000 Radio Sources: APM Identifications for the FIRST Radio Survey; McMahon, Richard G.; White, Richard L.; Helfand, David J.; Becker, Robert H., 2002, ApJS, 143, 1.
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae, Perlmutter S. et al, 1999, ApJ, 517, 565.
• Discovery of radio-loud quasars with z = 4.72 and z = 4.01; Hook, Isobel M.; McMahon, Richard G., 1998, MNRAS, 294, 7.
• Detection of Lyman-α emitting galaxies at redshift z = 4.55; Hu, Esther; McMahon Richard G., 1996, Nature, 382, 231.
• APM z >=4 QSO Survey: Spectra and Intervening Absorption Systems; Storrie-Lombardi, L. J.; McMahon, R. G.; Irwin, M. J.; Hazard, C., 1996, ApJ, 468, 121.
• https://ui.adsabs.harvard.edu/abs/1996MNRAS.283L..79S
• 1.25-mm continuum observations of very high-redshift QSOs: Is there dust at z = 4.69?, McMahon, R.G. et al, 1994, MNRAS, 267L, 9.

Career

 

Qualifications

• PhD, Institute of Astronomy, University of Cambridge; Supervisor: Cyril Hazard
• Postgraduate Certification in Secondary Education (Physics), University of Cambridge
• BSc (Hons) Physics, Queens University Belfast 

Awards and Prizes

• 2015 Breakthrough Prizes In Fundamental Physics for the discovery of the accelerating Universe (as a member of the Supernova Cosmology Project )
• 2007 Gruber Cosmology Prize for the discovery of the accelerating Universe (as a member of the Supernova Cosmology Project)

My letter of support for IoA EDI Juno Chamption Award application

National and International service roles

• 2015 - LSST-UK Executive Group member
• 2013-2021 4MOST Extragalactic Project Scientist
• More stuff

 

Current Departmental and University responsibilities

• Chair of Computing Oversight Committee
• Chair of School of Physcial Sciences IT Committee
• Member of the Information Services Committee Operations Sub-commitee
• Member of the Steering Committee for the Cambridge Big Data Strategic Research Initiative

 

Previous Departmental and University responsibilities

• Director of Institute of Astronomy
• Deputy Director of Institute of Astronomy
• Various IT and Computing related committees

Miscellaneous Information

• Who is the best connected scientist? A study of scientific coauthorship networks, Newman, Phys.Rev. E64 (2001) 016131; Phys.Rev. E64 (2001) [ Data ] "This analysis ranked me as 10th in the 'betweenness' category in Astronomy. See Table II on page 5"
• "Towards a better list of citation superstars: compiling a multidisciplinary list of highly cited researchers" According to this analysis I was the 63rd most highly cited researcher in any discipline, and the 23rd in astronomy.