Filaments, Bubbles, and Weak Shocks in the Gaseous Atmosphere of M87

By W. Forman, C. Jones, E. Churazov, M. Markevitch, P. Nulsen, A. Vikhlinin, M. Begelman, H. Böhringer, J. Eilek, S. Heinz and 3 more. 2006

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We present the first results from a 500 ks Chandra ACIS-I observation of M87. At soft energies (0.5-1.0 keV), we detect filamentary structures associated with the eastern and southwestern X-ray and radio arms. Many filaments are spatially resolved with widths of ~300 pc. This filamentary structure is particularly striking in the eastern arm, where we suggest the filaments are outer edges of a series of plasma-filled, buoyant bubbles whose ages differ by ~6 × 106 yr. These X-ray structures may be influenced by magnetic filamentation. At hard energies (3.5-7.5 keV), we detect a nearly circular ring of outer radius 2.8' (13 kpc), which provides an unambiguous signature of a weak shock, driven by an outburst from the supermassive black hole (SMBH). The density rise in the shock is ρshock/ρ0 ≈ 1.3 (Mach number, M ≈ 1.2). The observed spectral hardening in the ring corresponds to a temperature rise Tshock/T0 ≈ 1.2, or M ≈ 1.2, in agreement with the Mach number derived independently from the gas density. Thus, for the first time, we detect gas temperature and density jumps associated with a classical shock in the atmosphere around a SMBH. We also detect two additional surface brightness edges and pressure enhancements at radii of ~0.6' and ~1'. The ~0.6' feature may be overpressurized thermal gas surrounding the relativistic plasma in the radio cocoon, the "piston," produced by the current episode of AGN activity. The overpressurized gas is surrounded by a cool gas shell. The ~1' feature may be an additional weak shock from a secondary outburst. In an earlier episode, the piston was responsible for driving the 2.8' shock.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/f6e9141f48a3509012b3671aa88a5bfb01e8938a

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Citations in the corpus

Mechanical feedback from active galactic nuclei in galaxies, groups and clusters (2012, background): “In canonical systems like M87 (Forman et al 2007) and Perseus (Fabian et al 2011), as well as lesser known systems such as NGC 5044 (David et al 2009) and 2A0335 + 096 (Sanders et al 2009), energy is being deposited by multiple cavities, weak shocks and sound waves that are dissipating energy over…”
Jet-regulated cooling catastrophe (2010, background): “Observational evidence for strong AGN activity in groups and clusters is plenty (Arnaud et al. 1984; Carilli, Perley & Harris 1994; McNamara et al. 2001, 2005; Fabian et al. 2002; Bı̂rzan et al. 2004; Forman et al. 2007).”
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): “Concentric ripple-like features are also found around M87 in the Virgo cluster, and are interpreted there as weak shocks (Forman et al. 2007).”
STIRRING UP THE POT: CAN COOLING FLOWS IN GALAXY CLUSTERS BE QUENCHED BY GAS SLOSHING? (2009, background): “The currently favored mechanism is heating by the central AGN (e.g., Böhringer et al. 1993; Binney & Tabor 1995; McNamara et al. 2001, 2005; Fabian et al. 2006; Forman et al. 2007; for a recent review see McNamara & Nulsen 2006).”
What drives the growth of black holes (2011, background): “…of hot gas around AGN jets yield only a few clear examples of large-scale shocks, and these are predominantly in lowluminosity AGN with FR I morphologies (e.g., Forman et al., 2007; Croston et al., 2009), as opposed to the powerful FR II sources that are expected to drive the strongest shocks.”
X-ray spectroscopy of galaxy clusters: studying astrophysical processes in the largest celestial laboratories (2009, background): “This is due to the fact that the intracluster medium (ICM) has been heated to temperatures of tens of Millions of degrees (several keV per particle) which causes the hot plasma to emit the bulk of the thermal energy inthe regime of soft X-rays.”
X-RAY PROPERTIES OF THE FIRST SUNYAEV–ZEL'DOVICH EFFECT SELECTED GALAXY CLUSTER SAMPLE FROM THE SOUTH POLE TELESCOPE (2010, background): “The inferred density distribution has been shown previously to have little dependence on the temperature when determined from the surface brightness in this energy band (Mohr et al. 1999; Forman et al. 2007).”
A RELATIONSHIP BETWEEN AGN JET POWER AND RADIO POWER (2010, background): “Further,Pcav does not include energy channeled into shocks (e.g. Forman et al. 2007; Baldi et al. 2009a), which can exceed the energy in cavities (e.g. Nulsen et al. 2005).”
STRUCTURE AND FORMATION OF ELLIPTICAL AND SPHEROIDAL GALAXIES (2008, background): “However, it is the central giant elliptical in the cluster, and it is surrounded by an enormous X-ray halo which shows that the galaxy is at the bottom of a deep potential well (e. g., Fabricant & Gorenstein 1983; Böhringer et al. 1994; 2001; Forman et al. 2007).”