A high-resolution view of the jets in 3C 465

Abstract

We present new high-resolution and high-sensitivity studies of the jets in the WAT source 3C 465, using deep transverse-resolved radio observations from e-MERLIN, and with complementary observations from the VLA. We derive a lower limit ${\beta }_{\mathrm{j}}$ = (${\nu }_{\mathrm{j}}$/$c$) $\gtrsim$ 0.5 for the jet speed, and an upper limit ${\theta }_{\mathrm{j}}$ $\lesssim$ 61${}^{\circ }$ for the jet angle to the line of sight. The jet spectral index ($\alpha$, defined in the sense $S\propto {\nu }^{\alpha }$) is fairly constant (<${\alpha }_{\mathrm{jet}}$> = $-$0.7), and spectral flattening within 4.4 kpc of the core coincides with bright knots and is consistent with the site of X-ray particle acceleration at the base of the radio jet found in previous studies. There is little difference between the spectra of the two hotspot components, plausibly indicating that electron populations of the same properties are injected there. The NW and SE plumes are approximately homologous structures, with variations in mass injection and propagation in external pressure and density gradients in the two regions plausibly accounting for the slightly steeper spectrum in the NW plume, <${\alpha }_{\mathrm{NWp}}$> = $-$1.43 compared with the SE plume, <${\alpha }_{\mathrm{SEp}}$> = $-$1.38. Our synchrotron lifetime model supports plausible reacceleration of particles within the plume materials. Overall, our results show that the first-order Fermi process at mildly relativistic and non-relativistic shocks is the most likely acceleration mechanism at play in 3C 465 and distinguish differences between the acceleration at ${\beta }_{\mathrm{j}}$ $>$ 0.5 and ${\beta }_{\mathrm{j}}$ $<$ 0.5. The former case can accelerate electrons to higher Lorentz factors.

References in corpus (8)

• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• Revised equipartition & minimum energy formula for magnetic field strength estimates from radio synchrotron observations
• Fermi acceleration in astrophysical jets
• High-resolution radio observations of submillimetre galaxies
• Particle Acceleration in Mildly Relativistic Shearing Flows: the Interplay of Systematic and Stochastic Effects, and the Origin of the Extended High-energy Emission in AGN Jets
• Jet Speeds in Wide Angle Tailed Radio Galaxies
• A GMRT multifrequency radio study of the isothermal core of the poor galaxy cluster AWM 4
• The effect of a Chandra-measured merger-related gas component on the lobes of a dead radio galaxy

Cited by in corpus (1)

• Spatial variations of magnetic field along active galactic nuclei jets on sub-pc to Mpc scales