University Of Tasmania
138355 - The life cycle of radio galaxies in the LOFAR Lockman Hole field.pdf (1.08 MB)
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The life cycle of radio galaxies in the LOFAR Lockman Hole field

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journal contribution
posted on 2023-05-20, 13:25 authored by Jurlin, N, Morganti, R, Brienza, M, Mandal, S, Maddox, N, Duncan, KJ, Stanislav ShabalaStanislav Shabala, Hardcastle, MJ, Prandoni, I, Rottgering, HJA, Mahatma, V, Best, PN, Mingo, B, Sabater, J, Shimwell, TW, Tasse, C
Radio galaxies are known to go through cycles of activity, where phases of apparent quiescence can be followed by repeated activity of the central supermassive black hole. A better understanding of this cycle is crucial for ascertaining the energetic impact that the jets have on the host galaxy, but little is known about it. We used deep LOFAR images at 150 MHz of the Lockman Hole extragalactic field to select a sample of 158 radio sources with sizes > 60″ in different phases of their jet life cycle. Using a variety of criteria (e.g. core prominence combined with low-surface brightness of the extended emission and steep spectrum of the central region) we selected a subsample of candidate restarted radio galaxies representing between 13% and 15% of the 158 sources of the main sample. We compare their properties to the rest of the sample, which consists of remnant candidates and active radio galaxies. Optical identifications and characterisations of the host galaxies indicate similar properties for candidate restarted, remnant, and active radio galaxies, suggesting that they all come from the same parent population. The fraction of restarted radio galaxies is slightly higher with respect to remnants, suggesting that the restarted phase can often follow after a relatively short remnant phase (the duration of the remnant phase being a few times 107 years). This confirms that the remnant and restarted phases are integral parts of the life cycle of massive elliptical galaxies. A preliminary investigation does not suggest a strong dependence of this cycle on the environment surrounding any given galaxy.


Publication title

Astronomy and Astrophysics



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School of Natural Sciences


E D P Sciences

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7, Ave Du Hoggar, Parc D Activites Courtaboeuf, Bp 112, Les Ulis Cedexa, France, F-91944

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Copyright ESO 2020

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  • Open

Socio-economic Objectives

Expanding knowledge in the physical sciences