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Mutual distance dependence drives the observed jet-power–radio-luminosity scaling relations in radio galaxies

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posted on 2023-05-18, 17:45 authored by Godfrey, LEH, Stanislav ShabalaStanislav Shabala
The kinetic power of radio jets is a quantity of fundamental importance to studies of the AGN feedback process and radio galaxy physics. A widely used proxy for jet power is the extended radio luminosity. A number of empirical methods have been used to calibrate a scaling relationship between jet power (Q) and radio luminosity (L) of the form log (Q) = βL log (L) + C. The regression slope has typically been found to be βL ∼ 0.7–0.8. Here we show that the previously reported scaling relations are strongly affected by the confounding variable, distance. We find that in a sample of FRI X-ray cavity systems, after accounting for the mutual distance dependence, the jet power and radio luminosity are only weakly correlated, with slope βL ≈ 0.3: significantly flatter than previously reported. We also find that in previously used samples of high-power sources, no evidence for an intrinsic correlation is present when the effect of distance is accounted for. Using a simple model we show that βL is expected to be significantly lower in samples of FRI radio galaxies than it is for FRIIs, due to the differing dynamics for these two classes of radio source. For FRI X-ray cavity systems the model predicts βL(FRI) ≳ 0.5 in contrast to FRII radio galaxies, for which βL(FRII) ≳ 0.8. We discuss the implications of our finding for studies of radio mode feedback, and radio galaxy physics.

Funding

Australian Research Council

History

Publication title

Monthly Notices of the Royal Astronomical Society

Volume

456

Pagination

1172-1184

ISSN

0035-8711

Department/School

School of Natural Sciences

Publisher

Blackwell Publishing Ltd

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Rights statement

Copyright 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Repository Status

  • Open

Socio-economic Objectives

Expanding knowledge in the physical sciences

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