Quasar
Quasars (/ˈkweɪzɑr/) or quasi-stellar radio sources are the most energetic and distant members of a class of objects called active galactic nuclei (AGN). Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that appeared to be similar to stars, rather than extended sources similar to galaxies. Their spectra contain very broad emission lines, unlike any known from stars, hence the name "quasi-stellar". Their luminosity can be 100 times greater than that of the Milky Way.
While the nature of these objects was controversial until the early 1980s, there is now a scientific consensus that a quasar is a compact region in the center of a massive galaxy surrounding a central supermassive black hole. Its size is 10–10,000 times the Schwarzschild radius of the black hole. The energy emitted by a quasar derives from mass falling onto the accretion disc around the black hole.
(Wikipedia)
Illustration of Quasar Jet
>#1: Illustration of Quasar Jet
Illustration of Quasar Jet: This artist's rendering depicts the activity around the supermassive black hole at the center of a quasar that is being fueled by infalling gas and stars. This accretion process is often observed to be accompanied by powerful high-energy jets, as shown in this illustration.
Source: Massachusetts Institute of Technology
Source and information: Go to the source for more information.
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A broad absorption line (BAL) quasar
#2: A broad absorption line (BAL) quasar. (Link)
Image credit: European Space Agency
Source and Reference: Cosmic engines surprise XMM-Newton (12/29/2009)
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Quasars & Active Galaxies
Image credit: chandra.harvard.edu Illustration: NASA/CXC/M.Weiss
Source and information: Chandra X-ray Center.
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Einstein Cross
Einstein Cross
This NASA/ESA Hubble Space Telescope picture may trick you into thinking that the galaxy in it — known as UZC J224030.2+032131 — has not one but five different nuclei. In fact, the core of the galaxy is only the faint and diffuse object seen at the centre of the cross-like structure formed by the other four dots, which are images of a distant quasar located in the background of the galaxy.
The picture shows a famous cosmic mirage known as the Einstein Cross, and is a direct visual confirmation of the theory of general relativity. It is one of the best examples of the phenomenon of gravitational lensing — the bending of light by gravity as predicted by Einstein in the early 20th century. In this case, the galaxy’s powerful gravity acts as a lens that bends and amplifies the light from the quasar behind it, producing four images of the distant object.
This image is likely the sharpest image of the Einstein Cross ever made.
Image source: commons.wikimedia.org
The Chandra X-ray image is of the quasar PKS 1127-145
The Chandra X-ray image is of the quasar PKS 1127-145, a highly luminous source of X-rays and visible light about 10 billion light years from Earth. An enormous X-ray jet extends at least a million light years from the quasar.
Image source: commons.wikimedia.org
