Active galaxies produce tremendous amounts of energy from an extremely small region in the center of the galaxy. Active galaxies all contain central supermassive black holes, with masses of millions or even billions of times the mass of the Sun packed into a space smaller than our Solar system. These galaxies are "active" because their central supermassive black holes are swallowing immense amounts of gas (and stars and planets), and as this material spirals down into the deep gravitational well of the black hole, its gravitational potential energy is converted to kinetic energy, heat and radiation. Often active galaxies show powerful, very narrow, fast outflows or jets from the supermassive black hole. These jets can extend for hundreds of thousands of light years from the supermassive black hole, and can play an important role in shaping the environment around the galaxy, feeding material from the galaxy back into intergalactic space. The Chandra X-ray Observatory's high resolution imaging and its ability to create images in different X-ray colors have enabled revolutionary studies of the high energy emission from the hot inner regions of the jet, close to the jet launching point. Perhaps the best example of this is the Chandra image of the X-ray jet from the famous active galaxy 3C273, shown above. This Chandra image shows the hot X-ray emission from the accretion disk around the central supermassive black hole as a bright source of X-rays in the upper left of the image, and details the narrow jet of X-rays pointing from the nucleus and stretching for hundreds of thousands of lightyears from the center of the galaxy. The Chandra image revealed, for the first time, X-ray emitting material connecting the jet to the supermassive black hole. This observation and others like it have helped scientists understand the mysterious powerhouse at the centers of active galaxies.
Chandra Observes Cosmic Traffic Pile-Up In Energetic Quasar Jet (3C273) (press release)
Structure of the X-Ray Emission from the Jet of 3C 273 ~ H.L. Marshall et al
- Astrophysical Journal Letters 549(2):L167 (2001 Mar 10) DOI: 10.1086/319161
- arXiv.org > astro-ph > arXiv:astro-ph/0012162 > 07 Dec 2000
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