The X-Ray Cavity Around Hotspot E in Cygnus A: Tunneled by a Deflected Jet

Abstract

The powerful FR II radio galaxy Cygnus A exhibits primary and secondary hotspots in each lobe. A 2 Msec Chandra X-ray image of Cygnus A has revealed an approximately circular hole, with a radius of 3.9 kpc, centered on the primary hotspot in the eastern radio lobe, hotspot E. We infer the distribution of X-ray emission on our line-of-sight from an X-ray surface brightness profile of the radio lobe adjacent to the hole and use it to argue that the hole is excavated from the radio lobe. The surface brightness profile of the hole implies a depth at least 1.7 $\pm$ 0.3 times greater than its projected width, requiring a minimum depth of 13.3 $\pm$ 2.3 kpc. A similar hole observed in the 5 GHz VLA radio map reinforces the argument for a cavity lying within the lobe. We argue that the jet encounters the shock compressed intracluster medium at hotspot E, passing through one or more shocks as it is deflected back into the radio lobe. The orientation of Cygnus A allows the outflow from hotspot E to travel almost directly away from us, creating an elongated cavity, as observed. These results favor models for multiple hotspots in which an FR II jet is deflected at a primary hotspot, then travels onward to deposit the bulk of its power at a secondary hotspot, rather than the dentist drill model.

arXiv commentAccepted to ApJ, 12 pages, 7 figures, 5 tables

References in corpus (15)

• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• The Feedback-Regulated Growth of Black Holes and Bulges through Gas Accretion and Starbursts in Cluster Central Dominant Galaxies
• Sherpa: a Mission-Independent Data Analysis Application
• The microphysics of collisionless shock waves
• A Chandra X-ray Study of Cygnus A - III. The Cluster of Galaxies
• The Outburst of HST-1 in the M87 Jet
• AGN Jet Kinetic Power and the Energy Budget of Radio Galaxy Lobes
• The stratified two-sided jet of Cygnus A. Acceleration and collimation
• The Cavity of Cygnus A
• The Cluster of Galaxies Surrounding Cygnus A
• The Electron Energy Distribution in the Hotspots of Cygnus A: Filling the Gap with the Spitzer Space Telescope
• The Cocoon Shocks of Cygnus A: Pressures and Their Implications for the Jets and Lobes
• Multiwavelength study of Cygnus A II. X-ray inverse-Compton emission from a relic counterjet and implications for jet duty-cycles
• Detection of non-thermal X-ray emission in the lobes and jets of Cygnus A
• The X-ray Ribs Within the Cocoon Shock of Cygnus A

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