Dust heating in the cores of 3CRR radio galaxies

TL;DR

This study uses Spitzer observations to analyze infrared emissions in low-redshift 3CRR radio galaxies, revealing systematic variations linked to source power and identifying IR synchrotron and thermal emissions, with IR colors generally indicating passive galaxies.

Contribution

It provides new insights into the IR structures and spectra of 3CRR radio galaxies, showing how IR properties correlate with radio power and identifying specific emission mechanisms.

Findings

IR properties vary systematically with source power

IR synchrotron emission observed from jets and hotspots

Thermal emission detected from jet/gas interactions

Abstract

We have undertaken a Spitzer campaign to measure the IR structures and spectra of low-redshift 3CRR radio galaxies. The results show that the 3.6 - 160 micron infrared properties vary systematically with integrated source power, and so demonstrate that contemporary core activity is characteristic of the behaviour of sources over their lifetimes. IR synchrotron emission is seen from jets and hotspots in some cases. Thermal emission is found from a jet/gas interaction in NGC 7385. Most of the near-IR integrated colours of the low-redshift 3CRR radio galaxies are similar to those of passive galaxies, so that IR colours are poor indicators of radio activity.