Prize-winning research leads to cool science

This blog post was contributed by Prof. Patrick Roche, reporting from Geneva:

Today (2^nd July 2014) at the annual European Week of Astronomy and Space Science meeting in Geneva, Switzerland, the 2014 MERAC prize for the best doctoral thesis in astronomical technologies was awarded to Dr Boon Kok Tan (see: http://eas.unige.ch/merac_prizes.jsp). In his thesis studies at Oxford Astrophysics, supervised by Prof Ghassan Yassin, Boon worked on developments in coherent detector technologies for sub-millimetre wave astronomy. Developments in new technologies are fundamental in allowing new and more sensitive astronomical observations, and Boon's work included innovative approaches in feed horn antennae and advanced detector designs.

Sub-millimetre astronomy is an increasingly important regime for probing the cold and molecular Universe as well as galaxies at high redshift, giving clues to the formation history of stars and galaxies. Sub-millimetre wavelengths are strongly attenuated by water vapour in the Earth's atmosphere and so require observations from high dry sites; good sites include the summit of Mauna Kea at 4200m in Hawaii and the high plateau of the Chilean Atacama desert at 5000m, or space-based observatories could be used. Sub-millimetre waves lie between the far-infrared wavelength region – where emission from dust clouds heated by newly-formed stars or active galactic nuclei can dominate the output of dusty galaxies – and radio wavelengths which sample emission from clouds of electrons in nebulae or spiralling around magnetic fields. Sub-millimetre wavelengths cover emission from very cold dust and interesting molecules; this includes excited carbon monoxide, which is used to trace the molecular clouds that are indicative of star forming sites and provide information on their chemical and physical state in the Milky Way and other galaxies.

Dust ring around Fomalhaut seen by ALMA. Credit: ALMA (ESO/NAOJ/NRAO). Visible light image: the NASA/ESA Hubble Space Telescope

The newly-completed ALMA observatory in the Chilean Atacama desert now permits sensitive and high resolution observations of astronomical objects at sub-millimetre wavelengths, from planet-forming disks to molecular and nebular gas in distant galaxies. For the first time, the structures of disks have been revealed in detail. Sensitive observations at these wavelengths require superconducting detectors. Currently, most sub-millimetre instruments for studying molecular lines feed a single detector pixel; further advances in capability will arise from the application of multiple pixel detectors and higher frequency receivers.

Boon's thesis work was done in collaboration with other members of the Physics department and made use of the technical support available within Oxford Physics, and especially the mechanical workshops and central electronics groups.