RESOLVING THE RADIO SOURCE BACKGROUND: DEEPER UNDERSTANDING THROUGH CONFUSION

By J. Condon, W. Cotton, E. Fomalont, K. Kellermann, N. Miller, R. Perley, D. Scott, T. Vernstrom, J. Wall. 2012

157 citations recorded by the source corpus.

We used the Karl G. Jansky Very Large Array to image one primary beam area at 3 GHz with 8″ FWHM resolution and 1.0 μJy beam−1 rms noise near the pointing center. The P(D) distribution from the central 10 arcmin of this confusion-limited image constrains the count of discrete sources in the 1 < S(μJy) < 10 range. At this level, the brightness-weighted differential count S2n(S) is converging rapidly, as predicted by evolutionary models in which the faintest radio sources are star-forming galaxies; and ≈96% of the background originating in galaxies has been resolved into discrete sources. About 63% of the radio background is produced by active galactic nuclei (AGNs), and the remaining 37% comes from star-forming galaxies that obey the far-infrared (FIR)/radio correlation and account for most of the FIR background at λ ≈ 160 μm. Our new data confirm that radio sources powered by AGNs and star formation evolve at about the same rate, a result consistent with AGN feedback and the rough correlation of black hole and stellar masses. The confusion at centimeter wavelengths is low enough that neither the planned Square Kilometre Array nor its pathfinder ASKAP EMU survey should be confusion limited, and the ultimate source detection limit imposed by “natural” confusion is ⩽0.01 μJy at ν = 1.4 GHz. If discrete sources dominate the bright extragalactic background reported by ARCADE 2 at 3.3 GHz, they cannot be located in or near galaxies and most are ⩽0.03 μJy at 1.4 GHz.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/47de8c3b59527902aa794dd36d7563c23cddf959

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Citations in the corpus

The faint radio sky: radio astronomy becomes mainstream (2016, background): “(I consider here these two cases separately because the rapid rise observed in the counts for this sample is unique and might be caused by count corrections made for partial resolution of extended sources: Condon et al., 2012; Vernstrom et al., 2016).”
The GMRT 150 MHz all-sky radio survey - First alternative data release TGSS ADR1 (2016, background): “There is a rich literature on measured radio source counts at various frequencies (see Condon et al. 2012, and references therein), including the 100–200 MHz frequency range (e.g., Laing et al. 1983; Hales et al. 1988; McGilchrist et al. 1990; George & Stevens 2008; Ishwara-Chandra et al. 2010;…”
The VLA-COSMOS 3 GHz Large Project: Continuum data and source catalog release (2017, methodology): “Condon et al. (2012) performed single-pointing observations targeting the Lockman hole for 50-h on-source with the VLA in C-array configuration.”
GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey - I. A low-frequency extragalactic catalogue (2016, background): “Classical and sidelobe confusion also produce correlated noise that is dependent on the flux density of the source (Murdoch, Crawford & Jauncey 1973; Condon et al. 2012), with faint sources (<1 Jy) having a more significant degree of correlation across the entire MWA band, compared to bright…”
A HIGHLY CONSISTENT FRAMEWORK FOR THE EVOLUTION OF THE STAR-FORMING “MAIN SEQUENCE” FROM z ∼ 0–6 (2014, background): “In their stacking analysis, Condon et al. (2012) find that their estimates of source counts from lower angular resolution data are much lower than those of Owen & Morrison (2008), which are derived from much higher angular resolution data.”