Extreme active galactic nucleus feedback and cool-core destruction in the X-ray luminous galaxy cluster MACS J1931.8−2634

Abstract

We report on a deep, multiwavelength study of the galaxy cluster MACS J1931.8−2634 using Chandra X-ray, Subaru optical and Very Large Array 1.4-GHz radio data. This cluster (z = 0.352) harbours one of the most X-ray luminous cool cores yet discovered, with an equivalent mass, cooling rate within the central 50 h −1 70 kpc is ∼700 M yr −1 . Unique features observed in the central core of MACS J1931.8−2634 hint to a wealth of past activity that has greatly disrupted the original cool core. The X-ray and optical data suggest oscillatory motion of the cool core along a roughly north-south direction. We also observe a spiral of relatively cool, dense, X-ray emitting gas connected to the cool core, as well as highly elongated intracluster light (ICL) surrounding the cD galaxy. For a cluster with such a high-nominal cooling rate, this cluster is missing the central metallicity peak almost always seen in the cool-core clusters, which suggest bulk transport of cool gas out to large distances from the centre. Extended radio emission is observed surrounding the central active galactic nucleus (AGN), elongated in the east-west direction, spatially coincident with X-ray cavities. The power input required to inflate these 'bubbles' is estimated from both the X-ray and radio emission to reside between P jet ∼ 4-14 × 10 45 erg s −1 , putting it among the most powerful jets ever observed. This combination of a powerful AGN outburst and bulk motion of the cool core has resulted in two X-ray bright ridges to form to the north and south of the central AGN at a distance of approximately 25 kpc. The northern ridge has spectral characteristics typical of cool cores: it contains low-temperature high-density metal-rich gas and is consistent with being a remnant of the cool core after it was disrupted by the AGN and bulk motions. It is also the site of Hα filaments and young stars. The X-ray spectroscopic cooling rate associated with this ridge is ∼165 M yr −1 , which agrees with the estimate of the star formation rate from broad-band optical imaging (∼170 M yr −1 ). MACS J1931.8−2634 appears to harbour one of the most profoundly disrupted low-entropy cores observed in a cluster, and offers new insights into the survivability of cool cores in the context of hierarchical structure formation.

The jet-ISM interaction in the outer filament of Centaurus A

“…The jets are known to influence the conditions of the surrounding interstellar medium (ISM). Signatures of this are seen at both large (Nesvadba 2009;Ehlert et al 2011;McNamara & Nulsen 2012) and small (Rosario et al 2010a,b;Morganti et al 2013) scales in accordance with simulations (Mellema et al 2002;Fragile et al 2004;Wagner & Bicknell 2011). Recent studies of the interaction between a jet and its surrounding ISM have brought a number of surprises.…”

Cosmology and astrophysics from relaxed galaxy clusters – I. Sample selection

“…Specifically, the increasing peaky fraction implies that cool core disruption is more efficient in less massive halos. There are several known examples of cool cores being destroyed by ram pressure stripping as they oscillate (slosh) about the bottom of the cluster potential following a merger (Markevitch et al 2000, Mazzotta et al 2001, Million et al 2010, Ehlert et al 2011, Ichinohe et al 2014, a process also observed in hydrodynamic simulations (e.g. Burns et al 2008, ZuHone et al 2011.…”

DeepChandraobservation of the galaxy cluster WARPJ1415.1+3612 atz=1

“…There is increasing evidence from radio and X-ray observations of local clusters that the formation of bubbles due to radio jets associated to the central AGN may effectively satisfy the energy balance between cooling and heating in cool-core regions (Blanton 2001;Ehlert et al 2011). In this respect, the radio luminosity of the central galaxy provides an important link between the black hole activity and the state of the intracluster medium.…”