Exploiting magnification bias in ultradeep submillimetre-wave surveys using ALMA

摘要: The surface density of populations galaxies with steep/shallow source counts is increased/decreased by gravitational lensing magnification. These effects are usually called ‘magnification bias’ and ‘depletion’, respectively. However, if sources demagnified lensing, then the situation reversed, detectable a shallow count, as expected at faintest flux densities, increased. In general, difficult to detect study: exquisite subarcsec angular resolution brightness sensitivity required, emission from object must not dominate image. unusual conditions be satisfied for observations made dense swarm images that could form very close line sight through centre rich cluster using forthcoming submillimetre-wave Atacama Large Millimeter Array (ALMA) interferometer. most background lying within about 1 arcmin detected in single 18-arcsec-diameter ALMA field centred on core, providing an effective increase view. This technique allow representative sample faint, 10–100 μJy submillimetre several times more rapidly than blank field.