http://arxiv.org/abs/2202.05857
We present the first Chandra detection of a single X-ray cavity within the interstellar medium of the small Fanaroff-Riley type I (FRI) radio galaxy NGC 5141. The X-ray surface brightness depression, located $\approx 4$ kpc away from the galaxy center, is projected on the northern radio lobe, which is completely contained within the galaxy. The thermal gas surrounding the cavity, which extends to $\approx$ 20 kpc, has a bolometric X-ray luminosity (0.1 – 100 keV) of L${X}\approx2\times10^{40}$ erg s$^{-1}$ and a temperature of $kT\approx0.8$ keV. We calculated the total energy (E${cav} = 4PV \approx 10^{55}$ erg) required to inflate the cavity and its age ($t_{cav}\approx 9$ Myrs), assuming that it is filled with relativistic particles and rises buoyantly. The inferred total cavity power is as low as P${cav}=E{cav}/t_{cav}\approx6\times10^{40}$ erg s$^{-1}$, which is the lowest one among the radio-filled systems. Comparing $P_{cav}$ to the bolometric X-ray luminosity (i.e., the cooling luminosity), we conclude that NGC 5141’s central active galactic nucleus can heat the interstellar medium and balance its cooling luminosity, confirming that the $P_{cav}-L_{cool}$ relation, mainly tested on groups and clusters, also works for such a low-power system.
D. Macconi, P. Grandi, M. Gitti, et. al.
Tue, 15 Feb 22
13/75
Comments: 9 pages, 6 figures, accepted for publication in A&A on 28 January 2022