Speaker
Description
Radio-loud active galactic nuclei (AGN) feature heavily in our understanding of galaxy evolution. However, when it comes to studying their properties as a function of redshift and/or environment, the most-detailed studies tend to be limited by small-number statistics. In this talk, we will give an update on this new sample of 1,863 of the brightest radio-sources in the southern sky (Dec. < 30 deg). These were observed at low radio-frequencies as part of the GaLactic and Extragalactic All-sky MWA (GLEAM) survey, conducted using the Murchison Widefield Array (MWA). This instrument allows us to select radio-loud AGN in an orientation-independent way (i.e. minimising the bias caused by Doppler boosting, inherent in high-frequency surveys). In addition, the location of the MWA in a protected, radio-quiet zone means that we have excellent spectral coverage, with 20 flux-density measurements spanning a frequency range of 72-231 MHz. We have made a compilation of radio sources with integrated flux-density > 4 Jy at 151 MHz, which we refer to as the GLEAM 4-Jy (G4Jy) Sample (White et al., 2020a, 2020b). Following repeated visual inspection (using multi-wavelength information) and thorough checks against the literature, the G4Jy catalogue is now publicly available (see https://github.com/svw26/G4Jy), and includes mid-infrared identifications for 86% of the sources. For 129 sources, there is ambiguity concerning candidate host-galaxies, and this includes four sources (B0424−728, B0703−451, 3C 198, and 3C 403.1) where we question the existing identification. These ‘ambiguous’ sources have been followed-up using MeerKAT Open Time (PI: White), and we will present a few of those that have been re-imaged recently. With over 10 times as many sources as the best-studied, low-frequency radio-source sample that is optically complete (the revised Third Cambridge Catalogue of Radio Sources; 3CRR), the G4Jy Sample will allow models of radio-loud AGN to be tested more robustly.
| Suggested presentation duration (minutes) | 20 |
|---|
