Short Spacing Considerations for the ngVLA

Understand

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.