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The G4Jy-3CRE catalog: Powerful radio sources in the southern sky

Presentation #100.32 in the session AGN.

Published onJul 01, 2023
The G4Jy-3CRE catalog: Powerful radio sources in the southern sky

The survey of radio-loud active galaxies is an extremely challenging task mainly due to their low sky density; this prevents complete statistical analyses and constrains the validity of conclusions. Fundamental knowledge regarding powerful radio sources, their nature, and their environments have been achieved thanks to the Third Cambridge Catalog (3C). However, this catalog has some limitations: most of the data were collected with now relatively old astronomical facilities, and were only rarely updated; it lists radio sources lying in the northern hemisphere, where there is limited access to observations that can be performed with modern astronomical facilities, and from the 298 extragalactic radio sources in the 3C, ∼80% possess redshifts z < 1 and less than 10% possess redshifts z > 1.5, which does not allow for a full study of cosmological evolution. To mitigate these limitations, we present a new catalog of powerful radio sources visible in the southern hemisphere, extracted from the GaLactic and Extragalactic All-sky Murchison Widefield Array survey and the G4Jy sample and based on equivalent selection criteria as the 3CR. This new catalog, named G4Jy-3CRE (where “E” stands for “equivalent”) lists a total of 264 extragalactic radio sources. We explored archival radio maps obtained with different surveys and compared them with optical images available in the Pan-STARRS, DES, and DSS databases to search for optical counterparts of their radio cores. We compared mid-infrared counterparts, originally associated in the G4Jy, with the optical ones identified here. We carried out an extensive literature search to collect redshift estimates for all G4Jy-3CRE sources, resulting in a total of 145 reliable z measurements. Additionally, we show the results of the optical spectroscopic campaign on which we embarked as a first step to characterize the sample. These optical spectroscopic observations are crucial to provide redshift estimates for those sources without redshift and to classifying them. This step is fundamental to derive luminosities and sizes and to plan multifrequency observations to fully characterize this new sample.

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