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Session 46 - Radio Astronomy, Yesterday, Today and Tomorrow - II.
Oral session, Tuesday, June 11
Union Theater,
The National Radio Astronomy Observatory (NRAO) has formally organized the VLA Upgrade Project, with the immediate goal of producing, by mid-1997, a design study of upgrading the VLA to a state-of-the-art instrument. The design study will examine in detail a wide range of suggested improvements to the VLA's capability, including (but not limited to):
1. Retrofitting existing receivers with improved low-noise devices, and increasing the instantaneous bandwidth available for correlation to at least two GHz, while adding new frequency bands, centered near 2.7 and 33 GHz, extending the 21-cm band from the current limit of 1270 MHz to as low as 1000 GHz, and replacing the current low-frequency system with a wide-band prime focus system capable of continuous coverage from approximately 250 MHz through 1000 MHz.
2. Replacing the current LO/IF waveguide transmission system with a fiber-optic system capable of at least 2 GHz bandwidth, plus a new correlator, providing up to 8192 spectral channels from at least 33 antennas.
3. Addition of at least four new, fixed antennas. These, and at least two nearby VLBA stations will be connected by fiber to the new correlator to define a new 'A+' configuration with 8 times the resolution of the current VLA.
Implementation of these improvements would give astronomers a radio telescope capable of high fidelity imaging over a resolution range of 2500, with nearly continuous frequency coverage between 250 MHz to 50 GHz, to a sensitivity (between 2 and 30 GHz) of better than 3\muJy in 12 hours. The new correlator would provide unprecedented spectral resolution and flexibility. The new antennas would be used alone with the VLBA when the VLA is in its shorter configurations, resulting in a vast improvement in the VLBA's imaging capability, and complete elimination of the 'VLA-VLBA gap'.
