Issues

These are the issues we need to address to maximise the science from this survey. Discussion of these will occur on the wiki page.

• What is the confusion limit? Can we define a function which tells us (a) how often a source will overlap with another, (b) how often we will make a misidentification with surveys at other wavelengths, and (c) to what extent the background of confused sources adds to our Tsys? The answer will not clearly be a single number, but will be a function of flux desnity and observing frequency. We can then add another question: to what extent does this function vary over the sky because of cosmic sample variance?
  
  
• At what frequency should we observe? High frequencies give us a smaller synthesised beam, and hence better resolution, lower confusion, and a smaller probability of misidentification. Lower frequencies give us higher sensitivity to moderate-steep spectrum sources. Observing at two frequencies may allow us to transcend the classical confusion limit by subtracting off sources with a standard (-0.7) spectral index. And to what extent should we optimise use of observing time by choosing a frequency suitable for HI or OH megamaser projects?
  
  
• Can we transcend the classical confusion limit either by the use of two radio frequencies (as mentioned above) or by using (e.g.) MIR surveys to identify star-forming galaxies which can then be subtracted fom the radio images using the radio-MIR correlation? If so, should this deep survey be part of this project or spun off as a sperate project? Would it be better as a piggyback on the polarisation survey?
  
  
• What area of the sky do we aim to cover? Just the southern half of the sky (South of the celestial equator)? Or should we go further North (e.g. up to +20° declination) to get good overlap with LOFAR and other Northern surveys?
  
  
• Do we try to do a uniform survey covering the whole sky, progressively getting deeper, or should we focus on getting as deep as posible in one area before moving on to the next area? If the latter, which parts of the sky do we do first?
  
  
• What else?