The X-ray coronae of two massive galaxies in the core of the perseus cluster

Abstract

Abstract We study the X-ray properties of two elliptical galaxies, NGC 1270 and NGC 1272, in the core of the Perseus cluster with deep Chandra observations. Both galaxies have central supermassive black holes, the mass of which is 6.0 × 109 and 2.0 × 109 $\rm{M}_\odot$, respectively. Our aim is to examine relatively cool soft X-ray-emitting gas within the central region of these massive early-type galaxies. Such gas, referred to as a Minicorona in previous studies is common in the core of large elliptical cluster galaxies. It has not been completely stripped or evaporated by the surrounding hot intracluster medium and nor fully accreted on to the central black hole. With thermal emission from the minicorona dominating over any power-law radiation components, we find that both NGC 1270 and NGC 1272 encompass minicoronae, the temperature and radius of which are 0.99 and 0.63 keV; 1.4 and 1.2 kpc, respectively. For NGC 1272, the thermal coronal component dominates the core emission by a factor of over 10. We show that the depletion time-scale of minicoronal gas via viscous stripping is shorter by a factor of 100 than the replenishment time-scale due to stellar mass-loss. Magnetic fields are presumably responsible for suppression of the transport processes. Finally, we show that both objects have to meet a balance between cooling and heating as well as that among mass replenishment, stripping, and accretion.