Facilities > VLA > Data Processing

Data Processing

by mkrauss — last modified Jul 29, 2015 by Tony Perreault

The primary data reduction package for the VLA is the CASA (Common Astronomy Software Applications) package, which is also used for ALMA.  See http://casa.nrao.edu for more information on the latest release.

It is possible to reduce VLA data taken in all correlator modes that are offered for general observing using CASA.  More complex correlator set-ups are generally better handled by CASA, and advanced imaging algorithms are available in CASA.  The VLA calibration pipeline uses CASA.

The Astronomical Image Processing System (AIPS) can reduce all observations made with simple correlator set-ups (e.g., identical spw bandwidths and channel widths throughout).  AIPS is currently required for the reduction and analysis of phased-array VLA observations for VLBI and low-band observations (P-band, 230-470 MHz). NRAO will continue to support AIPS for the foreseeable future, at least until VLBI functionality and the full data path for frequencies below 500 MHz have been incorporated into CASA.  See http://www.aips.nrao.edu for more details.

The following pages are designed to help VLA observers understand, and process, their data. Note that these pages are a work in progress and many are placeholders for future content. For instructions on obtaining VLA data, see the archive web page. If you are new to radio astronomy (and interferometry in general), you might consider reading Chapter 7 of Astronomy Methods (Bradt, 2004) as well as the first several lectures in Synthesis Imaging in Radio Astronomy II (ASP Conference Series Vol. 180). You may also find useful information in the lectures from the 13th Synthesis Imaging Workshop.