The inverse-Compton X-ray-emitting lobes of the high-redshift giant radio galaxy 6C 0905+39

TL;DR

This study uses XMM-Newton data to analyze the X-ray emission from the lobes of a high-redshift giant radio galaxy, revealing insights into the energy deposition and emission mechanisms of its extended plasma.

Contribution

The paper provides detailed spectral characterization of the X-ray emission from the lobes and hotspots of 6C 0905+39, highlighting the impact of spent radio plasma on the environment at high redshift.

Findings

Extended X-ray emission is from CMB photon scattering by energetic electrons.

Hotspot emission appears softer, likely due to synchrotron radiation.

Significant energy has been deposited into the surroundings over 30 million years.

Abstract

We present new XMM-Newton data of the high-redshift (z=1.883), Mpc-sized giant radio galaxy 6C 0905+39. The larger collecting area and longer observation time for our new data means that we can better characterise the extended X-ray emission, in particular its spectrum, which arises from cosmic microwave background photons scattered into the X-ray band by the energetic electrons in the spent synchrotron plasma of the (largely) radio-quiet lobes of 6C 0905+39. We calculate the energy that its jet-ejected plasma has dumped into its surroundings in the last 3 X 10^7 years and discuss the impact that similar, or even more extreme, examples of spent, radio-quiet lobes would have on their surroundings. Interestingly, there is an indication that the emission from the hotspots is softer than the rest of the extended emission and the core, implying it is due to synchrotron emission. We confirm our previous detection of the low-energy turnover in the eastern hotspot of 6C 0905+39.