Pilot Survey

The VLASS Pilot Survey

The VLASS pilot survey was carried out during the summer of 2016 to test various aspects of the survey data acquisition and processing. The full requirements and survey definition are given in VLASS Memo #2. The survey had a total duration of 196 hr.

The observations were designed to map to key areas that are needed to inform the final survey design and provide observations of well-studied fields that will enable comparison with prior data, both at radio and other wavelengths. The areas we wished to explore were:

  1. Imaging of time variable sources.
  2. How the noise reduces with integration time.
  3. Transient detection algorithms.
  4. Imaging of compact sources.
  5. Imaging of extended sources.
  6. Completeness and reliability for compact sources.
  7. Completeness and reliability for extended sources.
  8. Systematics associated with data taking methods.
  9. Observation failure rate.
  10. Issues with southern declinations.
  11. Issues with very bright sources.
  12. Issues with fields transiting near zenith.
  13. Operational and post-processing workflow issues.
  14. Polarimetry.

 

The pilot survey fields:

FieldRA (hr)Dec (deg)ObservationArea (sq deg)# hrs
COSMOS 10 +2 3 epoch OTF 80 12
Cygnus 20.5 +40 3 epoch OTF 80 12
Cepheus 23.0 +62 3 repeat OTF 80 12
CDFS 3.5 -27 3 repeat OTF 80 12
Galactic Center 17.8 -29 3 repeat OTF 80 12
Stripe 82 21-03 0 3 epoch OTF 320 48
SDSS SGC 21-03 0 single OTF 1360 68
Lockman 11 +57 single OTF 80 4
ELAIS-N1 16 +54 single OTF 80 4
HATLAS-N/Bootes-1 14.5 +34.3 single OTF 80 4
HATLAS-N/Bootes-2 13.2 +28.0 single OTF 80 4
GOODS-N 12.6 +62 single OTF 80 4

VLASS Pilot Sky Coverage:

 

Data Products

Raw data from the VLASS pilot is available immediately via the NRAO archive, stored under project code TSKY0001. For the pilot, the only imaging products that were made by the VLASS project were the Quick Look images.

Please use this public GoogleSheet, NRAO VLASS Pilot, to find the associated file names (FSID) in the archive, the status of basic pipeline processing, any known potential issues (note in particular that the pointing tables in the data should not be used, taken prior to 2016 August 11 have very bad pointing tables, after date that we believe there is still a timing offset).

Connect with NRAO

The National Radio Astronomy Observatory and Green Bank Observatory are facilities of the U.S. National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Founded in 1956, the NRAO provides state-of-the-art radio telescope facilities for use by the international scientific community. NRAO telescopes are open to all astronomers regardless of institutional or national affiliation. Observing time on NRAO telescopes is available on a competitive basis to qualified scientists after evaluation of research proposals on the basis of scientific merit, the capability of the instruments to do the work, and the availability of the telescope during the requested time. NRAO also provides both formal and informal programs in education and public outreach for teachers, students, the general public, and the media.

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