The Planck-ATCA Co-eval Observations (PACO) project: the bright sample

TL;DR

The PACO project provides nearly simultaneous flux density measurements of radio sources across multiple frequencies, enabling improved calibration and understanding of spectral behavior and variability of bright radio sources.

Contribution

This study presents a comprehensive dataset of flux densities for a well-defined sample of radio sources, along with analysis of their spectral properties and variability, aiding calibration efforts.

Findings

Spectral behavior analysis of 189 bright sources

Variability characteristics over the observation period

Potential calibration transfer to ground-based telescopes

Abstract

The Planck-ATCA Co-eval Observations (PACO) have provided flux density measurements of well defined samples of AT20G radio sources at frequencies below and overlapping with Planck frequency bands, almost simultaneously with Planck observations. We have observed with the Australia Telescope Compact Array (ATCA) a total of 482 sources in the frequency range between 4.5 and 40 GHz in the period between July 2009 and August 2010. Several sources were observed more than once. In this paper we present the aims of the project, the selection criteria, and the observation and data reduction procedures. We also discuss the data in total intensity for a complete sample of 189 sources with S(20 GHz)>500 mJy, Galactic latitude |b|>5deg, and declination <-30deg, and some statistical analysis of the spectral behaviour and variability of this sample, referred to as the "bright PACO sample". Finally we discuss how these data could be used to transfer absolute calibrations to ground based telescopes using the CMB dipole calibrated flux densities measured by the Planck satellite, and we provide some test fluxes on bright calibrators.