The FIRST VLA Survey: The Automated Analysis Pipeline
Session 104 -- Radio Galaxies and AGN
Display presentation, Saturday, January 15, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [104.05] The FIRST VLA Survey: The Automated Analysis Pipeline

R.H.Becker (UC-Davis/LLNL), D.J.Helfand (Cambridge/Columbia), R.L.White (STScI)

In April 1993, the first 2200 fields of the FIRST (Faint Images of the Radio Sky at Twenty-cm) VLA survey were observed, covering a narrow strip $2.5\deg$ by $100\deg$ through the North Galactic Pole (NGP). This survey will eventually cover 10,000 square degrees around the NGP with 60,000 fields. The data are taken in the B-configuration of the VLA and have a 180~s integration time per field, resulting in a resolution of 5\arcsec\ FWHM and a sensitivity of 1~mJy ($6.5\sigma$).

We have built and tested an automated pipeline which edits, self-calibrates, and images the data. By taking advantage of the existing single-dish 20~cm source catalog derived from the Greenbank Sky Survey (White and Becker 1992) to reduce the required dirty map size used in the initial self-calibration steps, we have achieved a processing time per $2048\times2048$ image of 90~minutes per SPARC-10/41 processor. We map bright sources lying in sidelobes of the VLA primary beam without the need for any manual intervention or iteration of the mapping process. With the exception of the small number ($\sim\!5$\%) of fields containing sources brighter than $\sim\!150$~mJy, the resulting images achieve the theoretical sensitivity limit of 0.15~mJy rms at the field center. In addition, we demonstrate an absolute positional accuracy better than 0.3\arcsec\ over the entire field of view (50\arcmin).

The work is supported by the University of California CalSpace program and by IGPP, Lawrence Livermore National Laboratory.