The SIRTF First-Look Survey. I. VLA Image and Source Catalog

Abstract

The First-Look Survey (FLS) of the Space Infrared Telescope Facility (SIRTF) will cover about 5 deg^2 centered on J2000.0 α = 17^h18^m, δ = +59°30' in order to characterize the extragalactic infrared sky 2 orders of magnitude deeper than the IRAS survey. We expect that most of the FLS far-infrared (λ = 160, 70, and 24 μm) sources will be star-forming galaxies obeying the very tight far-infrared/radio correlation and will be continuum radio sources with flux densities S ≳100 μJy at ν = 1.4 GHz. Conversely, radio sources stronger than 100 μJy are usually powered by star-forming galaxies, plus some active galactic nuclei, and most should be detectable by the SIRTF FLS. Thus, a sensitive radio survey can be used to select and identify most of the SIRTF FLS source population before launch. We used the B configuration of the VLA to make an image of the FLS area at ν = 1.4 GHz with σ ≈ 23 μJy beam^(-1) rms fluctuations, θ = 5.”0 resolution, and σ_α ≈ σδ ≾0.”5 rms uncertainties in right ascension and declination. The resulting radio image and catalog of 3565 radio components with peak flux densities S_p ≥ 5 σ = 115 μJy beam^(-1) have been released via the Web to expedite follow-up optical identification and spectroscopy.