Imaging the Universe in the Far-Infrared

I have recently returned to Canada as a Canada Research Chair (CRC) in experimental astrophysics to establish a testbed for exploring the challenges associated with spatial/spectral interferometry at Far-Infrared (FIR) wavelengths. This is widely regarded as the technology that will lead to the next major advance in FIR imaging spectroscopy. Over half of the energy emitted by the Universe appears in the relatively unexplored FIR spectral region, most of which is opaque from ground-based sites necessitating space-borne instrumentation. The European Space Agency Planck and Herschel telescopes have recently provided the first unfettered views of the universe in the FIR. They have redefined current astrophysics including galactic and extragalactic sources, to the most distant photons possible. Herschel, with its 3.5m diameter primary mirror, has also highlighted the "FIR gap", i.e. the dramatically poorer angular resolution and sensitivity in the FIR compared with either side of this spectrum. Many Herschel discoveries are waiting on enhanced spatial resolution follow-up observations to address the questions raised in this new window on the Universe. The astronomy long range plan has identified cooled apertures and interferometry as two FIR roadmap priorities.

The Japanese-led Space Infrared Telescope for Cosmology and Astrophysics (SPICA) is the next-generation Herschel. With an actively cooled primary mirror similar in size to Herschel and more sensitive detectors, SPICA is expected to outperform Herschel in sensitivity by a factor of 100. Thus, SPICA will have greater mapping speed and sky coverage, but at similar spatial resolution to Herschel. Confusion limited photometric observations are obtained by Herschel in seconds of integration time. Even though SPICA's sensitivity will allow spectroscopic discrimination to partially circumvent spatial source confusion, we are approaching a fundamental limit in single-dish FIR capabilities. FIR improvements to much better spatial resolution are needed to lower the confusion limit and allow the full potential of other advances to be realized. Traditional imaging must be replaced by interferometric techniques to overcome this fundamental FIR barrier, much like interferometers such as the Atacama large millimetre array and square kilometre array are replacing single-dish observatories at other frequencies.

While my research is focused on the development of a lab-based FIR interferometry testbed, it contributes to many aspects of the FIR roadmap including the exploitation of current results and facilities, and collaboration with future experiments, facilities, and observatories. My research program is in partnership with the University of Lethbridge (UL) Astronomical Instrumentation Group (AIG). Led by David Naylor, the AIG provides a world-class environment with equipment in excess of $5M and an international reputation built over the last 30 years. The FIR interferometry focus opens a new research avenue for the AIG, and represents significant UL investment to build on international recognition within one of the key pillars in its strategic plan. My research provides a ground floor opportunity to become a key partner in future-generation space-based FIR astronomy, and excellent highly qualified personnel (HQP) training opportunities. This work is unique within Canada, and the world, complements the existing research network both locally and internationally, and will fortify existing and anticipated international collaborations into the future. My research will provide HQP training to many students through a combination of hands-on instrumentation, technology, technique, and data processing developments with the broad perspective of participation in international collaborations.

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