Short Spacing Considerations for the ngVLA

Abstract

The next generation Very Large Array project (ngVLA) would represent a major step forward in sensitivity and resolution for radio astronomy, with ability to achieve 2 milli-arcsec resolution at 100 GHz (assuming a maximum baseline of 300 km). For science on spatial scales of >~ 1 arcsec, the ngVLA project should consider the use of a large single dish telescope to provide short-spacing data. Large single-dish telescopes are complementary to interferometers and are crucial to providing sensitivity to spatial scales lost by interferometry. Assuming the current vision of the ngVLA (300 18m dishes) and by studying possible array configurations, I argue that a single dish with a diameter of >= 45m with approximately 20 element receiver systems would be well matched to the ngVLA for mapping observations.