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This study examines the interaction between the jets of Hydra A and the intracluster medium, including the radio morphology, reconfinement shocks, curved jet, and turbulent transition. It also explores the possibility of jet precession and discusses the laboratory jet experiments and astrophysical jet knots. The model setup, parameters, and best fit values are presented, along with the evolution of synthetic radio sources and the influence on the heating of the atmosphere. Additionally, the study looks into the precession period, precession angle, and the gentle heating of the ICM.
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Mohammad Ali Nawaz Prof. Geoffrey Bicknell RSAA, ANU Dr. Alexander Wagner Tsukuba University, Japan Dr. Ralph Sutherland RSAA, ANU Prof. Brian McNamara Waterloo University, Canada • Interaction of Hydra A Jets with the Intracluster Medium
Hydra A: Radio morphology hydra A 5 GHz Lobe Bright Knots 10 kpc 20 kpc 100 kpc Turbulent transition logIν(mJy/arcsec2) • Four bright knots Reconfinement shocks? • Curved jet Jet Precession? • Turbulent transition
Reconfinement shocks Reconfinement shocks in laboratory jets: Mach, 1890 Oscillation of the jet boundary: Prandtl, 1907 Turbulent transition Astrophysical jet knots are Reconfinement shocks Norman et al., 1982 Jet boundary oscillation Reconfinement Shocks Laboratory jet Simulated jet
Model setup Jet parameters Density parameter Lorentz factor Velocity Power Jet inlet radius Pressure Internal energy density Intracluster medium Atmosphere model based on the X-ray data presented in David et al. 2001
Axisymmetric Model Jet velocity from knot location Natural wavelength of non-relativistic supersonic flow Λ / r = 2.6 √(M2 - 1) Flow Mach number Inlet radius (Birkhoff & Zaranantonello 1957) Best fit values Jet composition βjet = 0.8 χjet = 13 Electron-positron jet: γ1 ~1 Electron-proton jet: γ1 ~700
Precessing Jet: Curvature Best fit model P = 1 Myr P = 1 Myr P = 5 Myr ψ = 20o ψ = 20o ψ = 15o 10 P = 10 Myr P = 15 Myr P = 25 Myr ψ = 20o ψ = 20o ψ = 20o Best fit parameters Precession period, P = 1 Myr Precession angle, ψ = 20o
Evolution of synthetic radio source Jet parameters: Pjet = 1045 ergs/s βjet = 0.8 pjet/pa = 5 χjet = 13 ICM: Modelled from the X-ray data of David et al. 2001 Grid resolution: 456 x 456 x 456 11 cells across the jet logIν(arbitrary scale)
Precessing Jet: Radio morphology Simulated jet Hydra A northern jet
Heating of the atmosphere M = 1.85 McNamara et al. 2012 -> Gentle heating
Jet precession period: Theoretical Time scale Outer disk angular momentum inner disk Black-hole spin-axis black hole Outer disk black hole spin parameter Black hole mass Disk height at radius r Precession time-scale Efficiency parameter Accretion disk paramater
Summary • 1. Bright knots are Reconfinement shocks. • 2. Jet Velocity from the spacing of the bright • knots and oscillation in the jet radius: • β =0.8c • (First time used in extragalactic jets) • 3. Complex radio morphology: • Jet Precession~1Myr period and 20o precession angle. • 4. Gentle Heating of the ICM • 5. Theoretical precession time-scale • of Hydra A jets: 1Myr