Bright Extragalactic AT20G Sources Polarization Catalog, 187 Objects

The Australia Telescope 20-GHz survey catalog provides polarization data for 187 extragalactic sources brighter than 500 mJy at 20 GHz and with Declination below -30 degrees. The sample is 99% complete for its selection criteria and has a 91.4% polarization detection rate at ~20 GHz, with multi-frequency observations for 172 sources. This table was created by the NASA HEASARC in January 2015 based on data from a dedicated 2006 observing run with the Australia Telescope Compact Array.

Use Cases

• Analyzing the relationship between polarization fraction and frequency based on multi-frequency observations at 4.8, 8.6, and 20 GHz.
• Estimating the distribution of polarization fraction and polarized flux density source counts at ~20 GHz.
• Investigating Faraday depolarization effects in extragalactic sources above 4.8 GHz.
• Studying the spectral properties of a bright, complete sample of southern hemisphere radio sources in total intensity and polarization.

Strengths

• High completeness (~99%) for sources brighter than 500 mJy at 20 GHz and Declination below -30 degrees.
• High polarization detection rate of 91.4% at ~20 GHz (94% for point-like sources).
• Multi-frequency polarization data for 172 sources, with 143 having detections at all three frequencies (4.8, 8.6, and 20 GHz).
• Observations were conducted during a dedicated, high-sensitivity run with sigma_P ~ 1 mJy.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• The selection epoch was 2006; source properties may have changed for variable objects.

Provenance

Source

NASA HEASARC, based on CDS Catalog J/MNRAS/436/2915.

Collection Method

Observations from the Australia Telescope Compact Array (ATCA) during a dedicated run on October 1, 2006, plus extracted data from 9-yr WMAP co-added maps for seven extended sources.

Time Range

Observations from 2006.

Freshness

Last updated 2026-03-13 19:58:06.114768; freshness should be verified.

Geography

Southern hemisphere (Declination below -30 degrees), excluding the Galactic plane (|b| <= 1.5 degrees) and the Large Magellanic Cloud region.