| Summary: | We have carried out a pilot study for the SCUBA-2 'All-Sky' Survey, SASSy, a wide and shallow mapping project at 850 μm, designed to find rare objects, both Galactic and extragalactic. Two distinct sets of exploratory observations were undertaken, and used to test the SASSy approach and data reduction pipeline. The first was a 0.5° x 0.5° map around the nearby galaxy NGC 2559. The galaxy was easily detected at 156 mJy, but no other convincing sources are present in the map. Comparison with other galaxies with similar wavelength coverage indicates that NGC 2559 has relatively warm dust. The second observations cover 1 deg² around the W5-E Hɪɪ region. As well as diffuse structure in the map, a filtering approach was able to extract 27 compact sources with signal-to-noise greater than 6. By matching with data at other wavelengths we can see that the SCUBA-2 data can be used to discriminate the colder cores. Together these observations show that the SASSy project will be able to meet its original goals of detecting new bright sources which will be ideal for follow-up observations with other facilities.
We have also carried out a study of MS 0451-03, a massive galaxy cluster at z=0.5, strongly lensing a group of galaxies at z=3. Imaging with SCUBA, and more recently with SCUBA-2, shows a prominent arc of submm emission, but lacks the resolution to break up this lensed structure into individual sources. ALMA, even in Early Science mode, has the ability to finally resolve the giant submm arc. A lensing reconstruction will allow us to relate the submm sources to lensed objects detected in other wavebands. The cluster-scale lensing and the extent of the galaxy group make this a relatively simple system to investigate. Lessons learned here could help us understand the effects of differential lensing on the spectral energy distribution in more complicated galaxy-scale lens systems. === Science, Faculty of === Physics and Astronomy, Department of === Graduate
|
|---|
