Prof Richard McMahon
[Research] [Publications] [Career] [Personal Sketch]
Research: Single sentence on my research: The discovery and characterization of super massive black holes in the young and distant Universe, to measure and understand hyrogen reionization and to measure the acceleration of the expansion of the Universe.
A common theme of my research is the development of observational techniques that exploit cutting edge technological developments to exlore the boundaries of the observable Universe. I work closely with researchers and engineers to ensure that I minimise the use of bleeding edge technology and I make progress by learning from my own mistakes and the mistakes of my colleagues.
The main scientific focus of my current research is in the study of galaxy formation and evolution in the Epoch of Reionization ; focusing on the discovery and characterisation of high redshift primeval active galaxies and quasars powered by the accretion of matter onto supermassive black holes. My research work includes 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 massive galaxies and quasars form.
This research is centered around the building and use of large scale data intensive techniques using optical and infra-red imaging and spectroscopic sensors on telescopes around the world (primarily in Chile) and in space using Gigapixel cameras and Petsacale multiwavelength datasets.
I worked on the experimental determination of the total mass of the Universe and the measurement of the rate of gravitational deceleration of the Universe. This work via the discovery of distant Supernova resulted in the unexpected discovery that the expansion of the Universe is accelerating. I am a member of the team that discovered the accelerating expansion of the Universe through observations of distant supernovae ( 1999ApJ...517..565P ). The team leader Saul Perlmutter was awarded the 2011 Nobel Prize in Physics for this discovery.
I am interesting in the use of quasar light curve time delay measurements for gravitationally lensed quasars and the detection of Baryon Acoustic Oscillations in quasar absorption lines caused by Hydrogen in order to determine whether the acceleration requires a new form Dark Energy or modifications to General Relativity on large (Giga light year) scales.
My current research focuses on the discovery and study of high redshift galaxies and quasars that contain supermassive (100-1000 million Solar mass) black holes; determining how their space density, star formation and accretion properties evolve with redshift; and using the quasars to probe the baryonic content of the Universe via intervening absorption lines from Hydrogen, Carbon, Nitrogen and Oxygen. My researdh group has pioneered the use of high redshift quasars to determine the mass of neutral hydrogen in the high redshift Universe via intervening absorption lines due to Hydrogen imprinted on the spectra of background high redshift quasars. I have also pioneered the use of mm and submm microwave radiation due to thermal black body radiation from to determine the star formation rate in quasar host galaxies.
I am the Principal Investigator (PI) of the VISTA Hemisphere Survey(VHS) which is an ambitious new near Infra-Red sky survey project which started in April, 2010. VHS has been been awarded around 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 has built the largest CCD camera in existence and has been awarded 500 nights on the CTIO 4m telescope in Chile to use this camera to observe at optical wavelengths part of the sky that will be surveyed in the near Infra-Red with the VISTA Hemisphere Survey. I am also working on the 4MOST project which is designing a wide field spectroscopic instrument for the VISTA telescope. Other projects that I am involved in, are the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) project and the ESA satellite mission EUCLID
The exploitation of the extremely large datasets from these new surveys requires the use and development of scalable 'Big Data' data-mining techniques that are robust to the effects of 'bad data'; distributed databases; machine-learning techniques such as decision trees, supervised learning and multi-dimensional data visualisation techniques.
Prizes and Awards
Current Departmental and University responsibilities
DIRAC bioProf Richard McMahon (PI: Cambridge): PI of DiRAC grants at Cambridge and member of DiRAC Steering Committee and Project Board since 2017. McMahon has over 25 years of experience of project management and data management in ground and space-based data intensive projects involving ESA (XMM), ESO (VISTA, 4MOST) and STFC (CASU, DES, LSST). Strabane, County Tyrone, a small town in Northern Ireland, half a mile from the Irish border. According to Wikipedia: "In the late 20th century, during the height of "The Troubles", Strabane garnered the dubious distinction of the highest unemployment rate in the industrial world. It was considered one of the most economically deprived towns in the United Kingdom. In August 2005, a Channel 4 television property programme named Strabane as the eighth-worst place to live in the UK, mainly due to high unemployment. Strabane had moved out of the top 20 in the 2008 edition."
I lived for one year when I was four years old in the town of Westport, County Mayo in the Republic of Ireland. As reported by Wikipedia, In 1842, the English novelist, William Makepeace Thackeray, visited Westport and wrote of the town:
"The most beautiful view I ever saw in the world. It forms an event in one's life to have seen that place so beautiful that is it, and so unlike other beauties that I know of. Were such beauties lying on English shores it would be a world's wonder perhaps, if it were on the Mediterranean or Baltic, English travellers would flock to it by hundreds, why not come and see it in Ireland!"
For, most of my school years, apart from one year in Westport and one year in Strabane, I lived in Omagh, County Tyrone, Northern Ireland where I attended the state funded Christian Brothers Grammar School, Omagh.
Omagh came to international notice in 1998, as a result of the Omagh bombing on 15 August 1998. The car bomb killed 29 people (including a woman pregnant with twins), making it the deadliest single incident of the Troubles in Northern Ireland.
I go to Omagh almost every summer with my family for a vacation and to visit my parents and siblings and usually spend a week on holiday in County Donegal, Ireland at a seaside town 45 miles from Omagh on the Atlantic coast called Rossnowlagh.
IOA Instrumentation Group Homepage | CIRSI(Sackler) Camera Homepage
Published by Richard G. McMahon <email@example.com>
Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 OHA
FAX: +44-(0)-1223-337523 Last modified: Sun Nov 6 12:29:06 GMT 2022