English

The Very Large Array Low-frequency Sky Survey Redux (VLSSr)

Instrumentation and Methods for Astrophysics 2015-06-19 v1 Cosmology and Nongalactic Astrophysics

Abstract

We present the results of a recent re-reduction of the data from the Very Large Array (VLA) Low-frequency Sky Survey (VLSS). We used the VLSS catalog as a sky model to correct the ionospheric distortions in the data and create a new set of sky maps and corresponding catalog at 73.8 MHz. The VLSS Redux (VLSSr) has a resolution of 75 arcsec, and an average map RMS noise level of σ0.1\sigma\sim0.1 Jy beam1^{-1}. The clean bias is 0.66×σ0.66\times\sigma, and the theoretical largest angular size is 36 arcmin. Six previously un-imaged fields are included in the VLSSr, which has an unbroken sky coverage over 9.3 sr above an irregular southern boundary. The final catalog includes 92,964 sources. The VLSSr improves upon the original VLSS in a number of areas including imaging of large sources, image sensitivity, and clean bias; however the most critical improvement is the replacement of an inaccurate primary beam correction which caused source flux errors which vary as a function of radius to nearest pointing center in the VLSS.

Keywords

Cite

@article{arxiv.1404.0694,
  title  = {The Very Large Array Low-frequency Sky Survey Redux (VLSSr)},
  author = {W. M. Lane and W. D. Cotton and S. van Velzen and T. E. Clarke and N. E. Kassim and J. F. Helmboldt and T. J. W. Lazio and A. S. Cohen},
  journal= {arXiv preprint arXiv:1404.0694},
  year   = {2015}
}

Comments

13 pages, 10 figures, accepted for publication in the MNRAS. For survey maps and catalogs, please see: http://www.cv.nrao.edu/vlss/VLSSpostage.shtml . The full electronic version of Table 1 is available at http://mnras.oxfordjournals.org/lookup/suppl/doi:10.1093/mnras/stu256/-/DC1

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