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physical object > natural object > celestial body > collection of stars > galaxy > emission line galaxy > violent galaxy

violent galaxy (eruptive galaxy, exploding galaxy)
subject			fact

violent galaxy	has synonym eruptive galaxy
	has synonym exploding galaxy
	has definition A type of galaxy differentiated only recently. Violent galaxies include QSOs and exploding galaxies like M82. About 1 percent of the galaxies are classified as violent. Violent galaxies release on the average 1058 ergs of energy, compared with a supernova release of 1049 ergs. Nearest violent galaxy is Cen A.
	is a kind of emission line galaxy
emission line galaxy	has emission lines
galaxy	has number of stars 106 to 1012
	has catalog galaxy catalog
celestial body	has spectra
physical object	has location or center of gravity
	has angular momentum
	has mass
	has velocity
	has momentum
	has temperature
	has volume
	has extent
	has material

Kinds of violent galaxy :

• quasar (2 kinds, 15 facts) (QSO) - The brightest objects in the universe, quasars can generate over a trillion times as much light as the Sun from a region little larger than the solar system. Most are extremely distant, which means that they existed long ago., An intensely bright extragalactic object which superficially resembles a star. Most exist at very high redshifts and are therefore thought to be the nuclei of active galaxies., Compact-looking objects, often radio sources, with emission lines in their spectrum which are displaced by very large amounts towards the red. These redshifts correspond to velocities which are a large fraction of the speed of light, and hence these objects are believed to lie at great distances., Extremely distant and luminous astronomical objects that are much smaller than a galaxy and much more luminous. Quasars may be the central regions of certain very energetic galaxies at an early stage of their evolution. It is believed that the power of a quasar derives from a massive black hole at its center., An object with a dominant starlike (i.e., diameter less than 1") component, with an emission line spectrum showing a large redshift - up to z = 3.53 (0.91c) for OQ 172. (The largest redshift known for a normal radio galaxy is z = 0.637 for 3C 123.) Many have multiple absorption redshifts; a few have multiple emission redshifts. (Bahcall system: class I, z_abs ≈ z_em; class II, z_abs significantly less than z_em.) The light of most if not all quasars is variable over time intervals between a few days and several years, so their diameters must not be much larger than the diameter of the solar system; yet they are the intrinsically brightest objects known (for 3C 273 (z = 0.158), M_v = -27.5 if its redshift is cosmological). The energy output of a typical quasar at "cosmological" distance is of the order of 10⁴⁷ ergs per second - which would require a mass of 10¹⁰ M_sun if it derives its energy solely from nuclear fusion. (Energy requirement under the "local" hypothesis is on the order of 10⁴² ergs per second.) The basic problem of quasars is that they emit too much radiation in too short a time from too small an area.

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