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PKS 2250-351: A giant radio galaxy in Abell 3936


Seymour, N and Huynh, M and Shabala, SS and Rogers, J and Davies, LJM and Turner, RJ and O'Brien, A and Ishwara-Chandra, CH and Thorne, JE and Galvin, TJ and Jarrett, T and Andernach, H and Anderson, C and Bunton, J and Chow, K and Collier, JD and Driver, S and Filipovic, M and Gurkan, G and Hopkins, A and Kapinska, AD and Leahy, DA and Marvil, J and Manojlovic, P and Norris, RP and Phillips, C and Robotham, A and Rudnick, L and Singh, V and White, SV, PKS 2250-351: A giant radio galaxy in Abell 3936, Publications of the Astronomical Society of Australia, 37 Article e013. ISSN 1323-3580 (2020) [Refereed Article]


We present a detailed analysis of the radio galaxy PKS 2250-351, a giant of 1.2 Mpc projected size, its host galaxy, and its environment. We use radio data from the Murchison Widefield Array, the upgraded Giant Metre-wavelength Radio Telescope, the Australian Square Kilometre Array Pathfinder, and the Australia Telescope Compact Array to model the jet power and age. Optical and IR data come from the Galaxy And Mass Assembly (GAMA) survey and provide information on the host galaxy and environment. GAMA spectroscopy confirms that PKS 2250−351 lies at 𝑧 = 0.2115 in the irregular, and likely unrelaxed, cluster Abell 3936. We find its host is a massive, 'red and dead' elliptical galaxy with negligible star formation but with a highly obscured active galactic nucleus dominating themid-IR emission. Assuming it lies on the localM–σ relation, it has an Eddington accretion rate of λEDD ∼0.014. We find that the lobe-derived jet power (a time-averaged measure) is an order ofmagnitude greater than the hotspot-derived jet power (an instantaneousmeasure). We propose that over the lifetime of the observed radio emission (∼300 Myr), the accretion has switched from an inefficient advection-dominatedmode to a thin disc efficient mode, consistent with the decrease in jet power.We also suggest that the asymmetric radio morphology is due to its environment, with the host of PKS 2250-351 lying to the west of the densest concentration of galaxies in Abell 3936.

Item Details

Item Type:Refereed Article
Keywords:radio continuum: galaxies – galaxies: active
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Cosmology and extragalactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Shabala, SS (Associate Professor Stas Shabala)
UTAS Author:Rogers, J (Mr Jonathan Rogers)
UTAS Author:Turner, RJ (Dr Ross Turner)
ID Code:136811
Year Published:2020
Funding Support:Australian Research Council (DE130101399)
Deposited By:Mathematics
Deposited On:2020-01-20
Last Modified:2020-05-20

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