The EVLA is the product of a program to modernize the electronics of the Very Large Array (VLA) in order to improve several key observational parameters by an order of magnitude or more. Some of the details of the EVLA Project may be found on the web, at http://www.aoc.nrao.edu/evla/. The EVLA is funded jointly by the US National Science Foundation (NSF), the Canadian National Research Council, and the CONACyT funding agency in Mexico. Total funding is approximately $94 million in Year 2006 dollars, including $59 million in new NSF funding, $16 million in redistributed effort from the NRAO Operations budget, $17 million for the correlator from Canada, and $2 million from Mexico. The EVLA project will be completed on time and on budget at the end of 2012, 11 years after it began. Its key observational goals are (1) complete frequency coverage from 1 to 50 GHz; (2) continuum sensitivity improvement by up to an order of magnitude (nearly two orders of magnitude in speed) by increasing the bandwidth from the VLA's 100 MHz per polarization to 8 GHz per polarization; and (3) implementation of a new correlator that can process the large bandwidth with a minimum of 16,384 spectral channels per baseline. A comparison of some of the EVLA performance parameters with those of the VLA is provided in Table 1. The remaining major milestones for the EVLA are shown in Table 2.
Table 1: Overall EVLA Performance Goals
Parameter | VLA | EVLA | Factor |
Continuum Sensitivity (1-σ, 9 hr) |
10 µJy |
1 µJy |
10 |
Maximum BW in each polarization |
0.1 GHz |
8 GHz |
80 |
Number of frequency channels at max. BW |
16 |
16,384 |
1024 |
Maximum number of freq. channels |
512 |
4,194,304 |
8192 |
Coarsest frequency resolution |
50 MHz |
2 MHz |
25 |
Finest frequency resolution |
381 Hz |
0.12 Hz |
3180 |
Number of full-polarization sub-correlators |
2 |
64 |
32 |
Log (Frequency Coverage over 1-50 GHz) |
22% |
100% |
5 |
- Note: The "Factor" gives the factor by which the EVLA parameter will be an improvement over the equivalent VLA parameter.
Table 2: EVLA Major Milestones
Milestone | Target Date | Status or Actual Date |
Installation of EVLA correlator subset for early science |
2010 Q1 |
2012 Q1 |
Shared Risk Observing begins |
2010 Q1 |
2012 Q2 |
Last antenna retrofitted |
2010 Q2 |
2010 Q2 |
Full EVLA correlator installation |
2011 Q2 |
2011 Q2 |
Last receiver installed |
2012 Q4 |
on schedule |
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