NRAO VLA Archive Survey (NVAS)

The Very Large Array (VLA) radio telescope, operated by the National Radio Astronomy Observatory (NRAO), has been collecting radio interferometry data (visibilities) since the late 1970's. The VLA data archive is a huge resource for radio images of astronomical sources. However, an in-depth knowledge of radio astronomy techniques is needed to obtain images from the visibility data. To make the VLA data archive useful to all astronomers, the NRAO has started the NRAO VLA Archive Survey (NVAS) project. The NVAS project goal is to produce images, on a best effort basis, from the visibility data archive using a general software pipeline and to make these images freely available to the astronomical community.

The first NVAS images were produced in October 2006; production has continued at an accelerating rate to the present. At the time of writing, NVAS contains images for 1- to 50-GHz continuum observations in D-, C-, B-, and (some) A-array configurations between 1993 and 2003. NVAS presently holds more than 51,000 VLA images of more than 9,000 unique sky positions. All data flagging, calibration, and imaging is done within the Astronomical Image Processing System (AIPS). Future development will extend NVAS to include all continuum observations as well as spectral line observations made with the VLA. NVAS images are published as a collection with the National Virtual Observatory (NVO).

The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.