The Cluster-Scale AGN Outburst in Hydra A

By P. Nulsen, B. McNamara, M. Wise, L. U. C. F. Astrophysics, On leave from University of Wollongong, D. Physics, Astronomy, Ohio University, M. C. S. Research. 2004

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Deep Chandra observations of the Hydra A Cluster reveal a feature in the X-ray surface brightness that surrounds the 330 MHz radio lobes of the AGN at the cluster center. Surface brightness profiles of this feature and its close association with the radio lobes argue strongly that it is a shock front driven by the expanding radio lobes. The Chandra image also reveals other new structure on smaller scales that is associated with the radio source, including a large cavity and filament. The shock front extends 200-300 kpc from the AGN at the cluster center, and its strength varies along the front, with Mach numbers in the range ~1.2-1.4. It is stronger where it is more distant from the cluster center, as expected for a shock driven by expanding radio lobes. Simple modeling gives an age for the shock front of ~1.4 × 108 yr and a total energy driving it of ~1061 ergs. The mean mechanical power driving the shock is comparable to quasar luminosities, well in excess of that needed to regulate the cooling core in Hydra A. This suggests that the feedback regulating cooling cores is inefficient, in that the bulk of the energy is deposited beyond the cooling core. In that case, a significant part of cluster "preheating" is a by-product of the regulation of cooling cores.

Subfields: Astronomy and Astrophysics, Instrumentation

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Citations in the corpus

Investigating AGN heating in a sample of nearby clusters (2006, background): “…radius which is offset by the energy of the bubble’s expansion. dThe bubble sizes for Hydra A are not those from the cluster scale outburst from Nulsen et al. (2005) but from the smaller, inner radio emission.eThese values for M87 come from the data in Ghizzardi et al. (2004) which extend to…”
INTRACLUSTER MEDIUM ENTROPY PROFILES FOR A CHANDRA ARCHIVAL SAMPLE OF GALAXY CLUSTERS (2009, background): “…doubt as evidenced by the prevalence of ICM bubbles (e.g., Bı̂rzan et al. 2004; Dunn & Fabian 2008), the possible presence of sound waves (Fabian et al. 2003; Sanders & Fabian 2008), and large-scale shocks associated with AGN outbursts (Forman et al. 2005; McNamara et al. 2005; Nulsen et al. 2005).”
The Compact, Conical, Accretion-Disk Warm Absorber of the Seyfert 1 Galaxy NGC 4051 and Its Implications for IGM-Galaxy Feedback Processes (2007, background): “…highly directional relativistic jets, and slower wide angle winds - has been recognized as a potentially crucial input to cosmology (e.g. Ciotti & Ostriker 1997; Magorrian et al. 1998; Gebhardt et al.; 2000; Ferrarese & Merritt 2000; Elvis et al. 2002; Hopkins et al. 2005; Nulsen et al. 2005).”
A deeper X‐ray study of the core of the Perseus galaxy cluster: the power of sound waves and the distribution of metals and cosmic rays (2007, background): “More powerful outbursts include those discovered in MS 0735.6+7421 (McNamara et al. 2005), Hercules A (Nulsen et al. 2005a) and Hydra A (Nulsen et al. 2005b).”
Hydrodynamical simulations of cluster formation with central AGN heating (2005, background): “A number of observational and theoretical works (e.g. Bîrzan et al. 2004; Sanderson, Finoguenov & Mohr 2005; McNamara et al. 2005; Nulsen et al. 2005a,b; Donahue et al. 2005; Voit & Donahue 2005) have constrained the plausible time interval between two successive bubble injection episodes to be of…”
Mechanical feedback from active galactic nuclei in galaxies, groups and clusters (2012, background): “However, the typical division between internal energy in the lobes and mechanical work done on the ICM has yet to be assessed (estimates exist for some cases, e.g., Forman et al 2005, Nulsen et al 2005, Randall et al 2011).”
X-ray spectroscopy of galaxy clusters: studying astrophysical processes in the largest celestial laboratories (2009, methodology): “In a combinedChandra and XMM-Newton study of the central region of the galaxy cluster associated with the radio source Hydra A, a similar front diagnostics has also been performed by Nulsen et al. (2005) and Simionescu et al. (2008a).”
Images, Structural Properties, and Metal Abundances of Galaxy Clusters Observed with Chandra ACIS-I at 0.1 < z < 1.3 (2007, background): “This could be related to the onset at lower redshifts of cooling cores and their regulation by AGN outbursts (e.g. Nulsen et al. 2005).”
Heating Hot Atmospheres with Active Galactic Nuclei (2007, background): “Modeled as a spherical shock from a nuclear outburst, the surface brightness discontinuities can be reproduced by conventional shock waves with Mach numbers lying between 1.2 and 1.7 (McNamara et al. 2005; Nulsen et al. 2005a,b).”
A semi-analytic model for the co-evolution of galaxies, black holes and active galactic nuclei (2008, background): “They include only the energy associated with inflating the bubbles, while significant energy can also be dissipated through sound waves, viscosity and weak shocks (McNamara et al. 2005; Nulsen et al. 2005a,b; Fabian et al. 2006; Forman et al. 2007).”
What is a cool-core cluster? a detailed analysis of the cores of the X-ray flux-limited HIFLUGCS cluster sample (2009, background): “A0780/Hydra-A Cluster This cluster is known to have a massive central AGN outburst (Nulsen et al. 2005).”
Bulge mass is king: the dominant role of the bulge in determining the fraction of passive galaxies in the Sloan Digital Sky Survey (2014, background): “…out of cold gas from the centre of galaxies in cataclysmic events such as during enhanced periods of nuclear activity throughout the major merging of gas rich galaxies (see Nulsen et al. 2005, Dunn et al. 2010, Feruglio et al. 2010, Fabian 2012, and Cicone et al. 2014 for observational evidence).”