|
Description
The initial Phoenix Deep Survey (PDS) observations with the Australia Telescope Compact Array (ATCA) have been supplemented by additional 1.4 GHz observations over the past few years. Here we present details of the construction of a new mosaic image covering an area of 4.56 deg<sup>2</sup> referred to as the Phoenix Deep field (PDF), an investigation of the reliability of the source measurements, and the 1.4 GHz source counts for the compiled radio catalog. The mosaic achieves a 1-sigma rms noise of 12 µJy at its most sensitive, and a homogeneous radio-selected catalog of over 2000 sources reaching flux densities as faint as 60 µJy has been compiled. The source parameter measurements are found to be consistent with the expected uncertainties from the image noise levels and the Gaussian source fitting procedure. A radio-selected sample avoids the complications of obscuration associated with optically selected samples, and by utilizing complementary PDS observations, including multicolor optical, near-infrared, and spectroscopic data, this radio catalog will be used in a detailed investigation of the evolution in star formation spanning the redshift range 0 < z < 1. The homogeneity of the catalog ensures a consistent picture of galaxy evolution can be developed over the full cosmologically significant redshift range of interest. The PDF covers a high-latitude region that is of low optical obscuration and devoid of bright radio sources. ATCA 1.4 GHz observations were made in 1994, 1997, 1999, 2000, and 2001 in the 6A, 6B, and 6C array configurations, accumulating a total of 523 hr of observing time. The initial 1994 ATCA observations (Hopkins et al. 1998, MNRAS, 296, 839; Hopkins 1998, PhD thesis) consisted of 30 pointings on a hexagonal tessellation, resulting in a 2 degrees diameter field centered on R.A. = 01<sup>h</sup> 14<sup>m</sup> 12.16<sup>s</sup>, Dec = -45<sup>o</sup> 44' 8.0" (J2000.0), with roughly uniform sensitivity of about 60 µJy rms. This survey was supplemented from 1997 to 2001 by extensive observations of a further 19 pointings situated on a more finely spaced hexagonal grid, centered on R.A. = 01<sup>h</sup> 11<sup>m</sup> 13.0<sup>s</sup>, Dec = -45<sup>o</sup> 45' 00" (J2000.0). The locations of all pointing centers are given in Table 1 of the reference paper. The final mosaic constructed from all 49 pointings was trimmed to remove the highest noise regions at the edges by masking out regions with an rms noise level greater than 0.25 mJy. The trimmed PDF mosaic image covers an area of 4.56 deg<sup>2</sup> and reaches to a measured level of 12 µJy rms noise in the most sensitive regions. The table contained here is the final merged catalog of PDS surveys based on the union of the 10% false discovery rate (FDR) threshold catalog (PDS_atca_fdr10_full_vis.cat) for the trimmed mosaic, visually edited to remove objects clearly associated with artifacts close to bright sources, containing 2058 sources, and the 10% FDR threshold catalog (PDS_atca_fdr10_deep.cat) for the 33' x 33' region centered on the most sensitive portion of the mosaic, containing 491 sources. The merged catalog was constructed to contain all unique catalogued sources; where common sources were identified, only the entry from PDS_atca_fdr10_deep.cat was retained. There are a total of 2148 sources in the final merged catalog, of which up to 10% may be false. This table was created by the HEASARC in November 2012 based on the file PDS_atca_fdr10_merge.cat, the merged PDS catalog (derived from the individual catalogs PDS_atca_fdr10_full_vis.cat and PDS_atca_fdr10_deep.cat as discussed in the Overview above), which was obtained from the first author's website <a href="https://web.archive.org/web/20171009234923/www.physics.usyd.edu.au/~ahopkins/phoenix/">https://web.archive.org/web/20171009234923/www.physics.usyd.edu.au/~ahopkins/phoenix/</a>. Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC .
|
