Related papers: Two Clusters with Radio-quiet Cooling Cores
We present an analysis of a Chandra ACIS-I observation of the massive galaxy cluster A644. This cluster was previously classified as a cooling flow, but no radio emission has been detected from its cD galaxy. Outside the core (R ~75 kpc…
We report on a deep, multiwavelength study of the galaxy cluster MACS J1931.8-2634 using Chandra X-ray, Subaru optical, and VLA 1.4 GHz radio data. This cluster (z=0.352) harbors one of the most X-ray luminous cool cores yet discovered,…
The origin of cool-core (CC) and non-cool-core (NCC) dichotomy of galaxy clusters remains uncertain. Previous simulations have found that cluster mergers are effective in destroying CCs but fail to prevent overcooling in cluster cores when…
We present new radio and X-ray observations of Abell 262. The X-ray residual image provides the first evidence of an X-ray tunnel in this system while the radio data reveal that the central radio source is more than three times larger than…
Chandra and XMM-Newton observations have confirmed the presence of large temperature gradients within the cores of many relaxed clusters of galaxies. Here we investigate whether thermal conduction operating over those gradients can supply…
We present a study of strong cool core, highly-luminous (most with L_x > 10^(45) erg/s), clusters of galaxies in which the mean jet power of the central active galactic nucleus must be very high yet no central point X-ray source is…
Galaxy clusters are filled with hot, diffuse X-ray emitting plasma, with a stochastically tangled magnetic field whose energy is close to equipartition with the energy of the turbulent motions \cite{zweibel1997, Vacca}. In the cluster…
New Chandra X-ray and Herschel FIR observations enable a multiwavelength study of active galactic nucleus (AGN) heating and intracluster medium (ICM) cooling in the brightest cluster galaxy of Abell 2597. The new Chandra observations reveal…
New radio and X-ray data are reported for the rich cluster Abell 2255. The cluster radio emission is characterized by the presence of a diffuse halo source, located at the cluster center, and a more peripheral ridge of radio emission which…
We derive X-ray mass, luminosity, and temperature profiles for 45 galaxy clusters to explore relationships between halo mass, AGN feedback, and central cooling time. We find that radio--mechanical feedback power (referred to here as "AGN…
While rich clusters are powerful sources of X-rays, gamma-ray emission from these large cosmic structures has not been detected yet. X-ray radiative energy losses in the central regions of relaxed galaxy clusters are so strong that one…
We simulate the effects of viscous dissipation of waves that are generated by AGN activity in clusters of galaxies. We demonstrate that the amount of viscous heating associated with the dissipation of these waves can offset radiative…
The brightest cluster galaxy (BCG) in the Abell 1664 cluster is unusually blue and is forming stars at a rate of ~ 23 M_{\sun} yr^{-1}. The BCG is located within 5 kpc of the X-ray peak, where the cooling time of 3.5x10^8 yr and entropy of…
(Abridged) The prevalence of radio-loud AGN activity in present-day massive halos is determined using a sample of 625 nearby groups and clusters from the SDSS. Brightest group and cluster galaxies (BCGs) are more likely to host a radio-loud…
Galaxy clusters are the most massive collapsed structures in the universe whose potential wells are filled with hot, X-ray emitting intracluster medium. Observations however show that a significant number of clusters (the so-called…
Galaxy cluster cores are pervaded by hot gas which radiates at far too high a rate to maintain any semblance of a steady state; this is referred to as the cooling flow problem. Of the many heating mechanisms that have been proposed to…
Radio mini-halos are perplexing features, typically hosted by X-ray cool-core galaxy clusters. Understanding the connection between thermal X-ray and non-thermal radio emission is key to uncovering their origin. Here, we present a…
It has been proposed that the cool cores of galaxy clusters are stably heated by cosmic rays (CRs). If this is the case, radio mini-halos, which are often found in the central regions of cool core clusters, may be attributed to the…
The existence of cooling flows in the center of galaxy clusters has always been a puzzle, and in particular the fate of the cooling gas, since the presence of cold gas has never been proven directly. X-ray data from the satellites Chandra…
Our understanding of how AGN feedback operates in galaxy clusters has improved in recent years owing to large efforts in multi-wavelength observations and hydrodynamical simulations. However, it is much less clear how feedback operates in…