Earlier informal reviews of the scientific motivations for enhancing the VLA identified needs for major gains in four areas:
The following technical capabilities are therefore key ingredients in a VLA Development Plan:
Phase 1: An Ultra-Sensitive Array
GHz in each polarization channel)
in existing bands; add 2.4 GHz and 33 GHz bands at the Cassegrain
focus; complete the outfitting at the 40-50 GHz band; extend the 1.4
GHz band to lower frequencies.
antennas,
to process both broadband continuum signals
and to provide improved resolution and flexibility for spectral line
work.
Phase 2: The VLA Expansion
The combination of these enhancements will yield an instrument with many fundamentally new capabilities. The continuum sensitivity will improve by more than an order of magnitude in some bands (Table 1.2). New and powerful spectral line observations will be possible and significantly more frequency choices will be available. The super-compact E configuration will allow fast imaging of large fields and large objects, greatly enhancing the capabilities of surveys. Linkages to the innermost VLBA antennas and the new antennas will increase the maximum angular resolution by a factor of seven. The sensitivity increases will allow the increase in angular resolution to be exploited fully when observing a wide (and in many cases for the first time, representative) variety of thermal and nonthermal objects, both galactic and extragalactic. Each of these project elements is now discussed in more detail.