BLAST

The subject of my Ph.D. thesis and current primary area of work is the Balloon-borne Large-Aperture Submillimeter Telescope (BLAST), a 2-metre telescope designed to study star formation in the Galaxy and in the early Universe. Star formation is particularly bright in the submillimetre wavebands, as the optical and ultra-violet light emitted by young stars is absorbed by the surrounding interstellar dust from which the star formed. The dust is heated by the star light and radiates thermally at infrared wavelengths. A telescope sensitive to this thermal radiation can thus detect star formation that is hidden to optical telescopes.

The primary motivation behind building BLAST is to be able to study massive star formation at high cosmological redshifts, that is, the formation of galaxies in the very early Universe. Since the Universe is expanding, the light from these galaxies is redshifted from the infrared (around 0.1 mm) to the submillimetre (around 0.2 – 0.4 mm). Unfortunately, submillimitre light is strongly absorbed by water vapour in the atmosphere, so sensitive observations must be made from space or near-space conditions.

In order avoid to prevent strong signal attenuation from the atmosphere, BLAST makes use of the scientific balloon platform, observing from an altitude of 40 km, above 99% of the Earth's atmosphere. In order to achieve the sensitivity needed, BLAST must observe for several days at a time. However, the instrument runs on solar power and must therefore operate in daylight. It is therefore necessary to observer from the Artic or Antarctic during the Summer when the Sun does not set.

BLAST's first scientific flight took place in June, 2005. It was a 5-day flight, launched from northern Sweden and flying over the Atlantic to northern Canada. The telescope unfortunately suffered a degredation of the quality of the optics, significantly smearing the images made during the flight. Due to this, we were unable to perform sensivity extragalactic observations and concetrated most of the flight observing Galactic star forming regions. Initial results can be seen here.

As soon as the instrument was recovered, we began fixing it up for a second run. The problem with the optics was corrected and a second science flight took place in Antartica in December, 2006. The 11-day flight was a huge success. We released our first set of papers, including a letter in Nature magazine, in April, 2009. See our results page.