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VLA Sky Survey

by Davis Murphy last modified Jun 01, 2017 by Mark Lacy

VLASS logo (dark)News Update: June 2017 

VLASS survey status. The VLASS has completed its Critical Design Review, and, subject to the resolution of two relatively minor issues, is on track to begin as planned in September 2017.

Pilot Survey Status. The VLASS Pilot Survey was completed in September 2016. 196 hours were observed in the fields listed in VLASS Memo #2, and raw data may be found in the archive under the TSKY0001 project code. About 20% of the data has now been passed through the calibration pipeline, and we will be undertaking the production of "Quick Look" (Stokes I, 1-arcsec per pixel) images over the summer.

VLASS Memo Series. A series of VLASS memos has been written describing various aspects of the survey, ranging from the science case for the survey to technical details of the execution and calibration of the survey. The memo series may be found on the VLASS public wiki.

Reminder: A Google Group has been set up to facilitate communication and discussion on the Science Working Group, open to all.  Please sign up by visiting the above link!


A new sky survey for an enhanced VLA

Very Large ArrayIn the 20 years since the initial observations were made for the NRAO VLA Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST), these pioneering programs have defined the state-of-the-art in centimeter radio sky surveys and produced a steady stream of excellent science. Given the enhanced capabilities of the Jansky Very Large Array (VLA), now is an appropriate time to exploit the scientific potential of new centimeter-wavelength sky surveys.

The astronomy community has already recognized that several of the high priority science goals of the 2010 decadal survey New Worlds, New Horizons in Astronomy and Astrophysics could be addressed by a new VLA sky survey. At the May 2013 Radio Astronomy in the LSST Era held at NRAO-Charlottesville, for example, many scientists expressed keen interest in employing the VLA to conduct new, wide-area centimeter wavelength sky surveys in support of multi-wavelength synoptic surveys using existing and future facilities, such as the Large Synoptic Survey Telescope (LSST).

Thus, we are undertaking a NRAO VLA Sky Survey (VLASS) initiative to design and execute a new centimeter-wavelength survey. A community-led Science Survey Group (SSG) defined the science program and key components of VLASS, and NRAO will support its technical definition and implementation. All VLASS data will be available immediately to the community.

The VLASS will consist of a survey of the entire sky visible to the VLA (34000 square degrees) in three epochs, each epoch reaching a flux density limit of 0.12mJy at 3GHz. The survey will have a resolution of 2.5" and be carried out in the S-band of the VLA in B configuration. The survey will cover the range 2-4GHz (less some excisions due to RFI) and be carried out in full polarization. Observations will be spread out over seven years (six cycles of the B configuration) to both minimize the impact on PI science and to deliver a long time baseline for studies of transients and variability.