VLASS News

We have added a page to the VLASS website for contributed software and scripts. This is intended to provide links to external repositories of software that users of VLASS may find useful. Currently, links are provided to the CIRADA software repository, and to a GitHub repository of scripts to make custom VLASS images maintained by Erik Carlson (University of Rhode Island). If you know of (or have written) any software you would like to have added to this site, please let us know by submitting a ticket to the VLASS department of the NRAO Helpdesk. Note that these links are provided as-is, the VLASS project takes no responsibility for the contents of these links and users should, as ever,  exercise caution when downlinking any software from unfamiliar sites. 

We held the VLA Sky Survey in the Multiwavelength Spotlight conference in Socorro from 7th-9th September 2022. Presentations (slides and recorded talks) are now available to all on the program page of the conference website

The first version of the Epoch 2 Quick Look Catalogue and Epoch 2 Single Epoch Catalogue for the Very Large Array Sky Survey (VLASS) have now been released to the public and communities by the Canadian Initiative for Radio Astronomy Data Analysis (CIRADA). Each catalogue consists of three tables: a Component Table, a Host ID Table, and Subtile Information Table that provides metadata on the quick-look images used to produce the catalogue. The single epoch catalogue also contains information about the spectral indices for the identified components. An enhanced “Catalogue User Guide” with a complete description of the catalogue production, data models and known data quality issues is also provided to the public and communities with the catalogues release. For more information, please click here. 

The VLASS will be presenting a number of talks and a splinter session at the upcoming AAS242 meeting in Albuquerque, NM, June 4-8 2023! See here for details.

Susan Xu (CIRADA) and Steven Myers (NRAO)

CIRADA is excited to announce the release of a double radio galaxy catalog and new machine learning classifications for the VLASS Quick Look epoch 2 data. The Double Radio Galaxy (DRAGNs) Catalog contains over 17,000 double-lobed radio galaxies and supplementary information such as host IDs and, where possible, redshift measurements. We also include  a value-added list of more than 500,000 single-component radio sources.  DRAGN catalogs are now available for each of the existing component catalogs, namely Quick Look 1, 2  and Single Epoch 2. Researchers can access the catalog and the accompanying software on our website at cirada.ca<http://cirada.ca/>. Detailed descriptions are provided in Gordon et al., 2023, ApJS, 267, 37.

CIRADA also now introduces morphological annotations of radio sources created using a Self-Organizing Map (SOM) for the epoch 2 data. This unsupervised machine learning technique classifies VLASS sources based on their distinct morphologies into 100 different classes or ‘neurons.’ Such classifications not only provide quality flags to identify bad data but are also beneficial for researchers interested in creating samples based on radio morphologies. Details of potential issues and guidance on such selection are provided in the Catalog User Guide at cirada.ca<http://cirada.ca/>.

With this release, we have also corrected any astrometry errors that corrupted the previous versions of the Quick Look epoch 1 catalog.

See NRAO E-News article.

Observations for VLASS3.2 are expected to begin this week of 29th April 2024. VLASS3.2 completes the third epoch of VLASS observations and thus the original scope of the project (though a fourth epoch may be scheduled, pending review of a 4th epoch proposal). Quick Look images from VLASS3.2 observations will be made available at archive-new.nrao.edu/vlass 3-6 weeks after observations are made. The progress of observations can be checked on https://archive-new.nrao.edu/vlass/VLASS_dyn_summary.php