Hydrodynamical backflow in X-shaped radio galaxy PKS 2014−55. Issue 1 (7th May 2020)

• Record Type: Journal Article
• Authors: Cotton, W D; Thorat, K; Condon, J J; Frank, B S; Józsa, G I G; White, S V; Deane, R; Oozeer, N; Atemkeng, M; Bester, L; Fanaroff, B; Kupa, R S; Smirnov, O M; Mauch, T; Krishnan, V; Camilo, F
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 495:Issue 1(2020)
• Page Start: 1271
• Page End: 1283
• Publication Date: 2020-05-07
• Subjects: hydrodynamics -- ISM: individual objects: PGC 064440 -- galaxies: active -- galaxies: jets -- radio continuum: galaxies -- radio lines: galaxies; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa1240
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present MeerKAT 1.28 GHz total-intensity, polarization, and spectral-index images covering the giant (projected length l ≈ 1.57 Mpc) X-shaped radio source PKS 2014−55 with an unprecedented combination of brightness sensitivity and angular resolution. They show the clear 'double boomerang' morphology of hydrodynamical backflows from the straight main jets deflected by the large and oblique hot-gas halo of the host galaxy PGC 064440. The magnetic field orientation in PKS 2014−55 follows the flow lines from the jets through the secondary wings. The radio source is embedded in faint ($T_\mathrm{b} \approx 0.5 \mathrm{\, K}$ ) cocoons having the uniform brightness temperature and sharp outer edges characteristic of subsonic expansion into the ambient intragroup medium. The position angle of the much smaller ( l ∼ 25 kpc) restarted central source is within 5° of the main jets, ruling out models that invoke jet re-orientation or two independent jets. Compression and turbulence in the backflows probably produce the irregular and low polarization bright region behind the apex of each boomerang as well as several features in the flow with bright heads and dark tails.