Radio astronomy data from the Very Large Array Sky Survey (VLASS).
As written in the VLASS homepage, VLASS is a survey of the universe through the use of the Very Large Array (VLA) in New Mexico. The VLA is one of the most sensitive telescopes in the radio band that can provide more sensitive images of the universe than any other radio telescope in the world. This, however, requires processing large volumes of data and super-computer class computing resources. The VLASS is designed to produce a large collection of radio data available to wide range of scientists within the astronomical community. VLASS's science goal is to produce a radio, all-sky survey that will benefit the entire astronomical community. As VLASS completes its three scans of the sky separated by approximately 32 months, new developments in data processing techniques will allow scientists an opportunity to download data instantly on potentially millions of astronomical radio sources.
The data in this data origin consists of interferometric visibilities stored in (Measurement Set (MS)) format. Each dataset contains calibrated visibilities for one of the sixteen spectral windows of the VLA and covers an area of 4 square degrees (2 degrees x 2 degrees) in the sky. All sixteen spectral windows are combined to generate a single image, so that the data contained in this data origin can be used to make images of approximately 70 regions in the sky, each image covering 4 square degrees. The LibRA software package is used to transform visibilities to images. The architecture and design considerations for LibRA are shown in this presentation.
Teams of scientists at the National Radio Astronomy Observatory (NRAO), Socorro, NM and the Center for High Throughput Computing (CHTC) have used the PATh and NRP facilities of the OSG to make the deepest image in the radio band of the Hubble Ultra-deep Field (HUDF). Similarly, the COSMOS HI Large Extra Galactic Survey (CHILES)[http://chiles.astro.columbia.edu/] project has 1000 hr of integration with the VLA on the COSMOS field. Imaging the CHILES data using PATh and NRP facilities delivered the deepest radio image of this region of the sky, at an unmatched data processing throughput. Similarly to the VLASS data stored in this data origin, the data for HUDF and CHILES is stored in the PATh facility data origin. These recent large scale imaging achievements that were made possible through use of OSG resources are reported in this [NRAO Newsletter article] (https://science.nrao.edu/enews/17.3/index.shtml#deepimaging) and this press release.