The Balloon-borne Large-Aperture Submillimeter Telescope for polarization: BLAST-pol

摘要

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is a sub-orbital experiment designed tostudy the process of star formation in local galaxies (including the Milky Way) and in galaxies at cosmologicaldistances. Using a 2 m Cassegrain telescope, BLAST images the sky onto a focal plane, which consists of 270bolometric detectors split between three arrays, observing simultaneously in 30% wide bands, centered at 250,350, and 500 pm. The diffraction-limited optical system provides a resolution of 30" at 250 pm. The pointing system enables raster-like scans with a positional accuracy of ~ 30", reconstructed to better than 5" rms in post-flight analysis. BLAST had two successful flights, from the Arctic in 2005, and from Antarctica in 2006, whichprovided the first high-resolution and large-area(~0.8 - 200 deg~2) submillimeter surveys at these wavelengths.As a pathfinder for the SPIRE instrument on Herschel, BLAST shares with the ESA satellite similar focal planetechnology and scientific motivation. A third flight in 2009 will see the instrument modified to be polarization-sensitive (BLAST-pol). With its unprecedented mapping speed and resolution, BLAST-pol will provide insightsinto Galactic star-forming nurseries, and give the necessary link between the larger, coarse resolution surveysand the narrow, resolved observations of star-forming structures from space and ground based instruments beingcommissioned in the next 5 years.