So a quasar at an absolute magnitude of − 25. 5 is 100 times brighter than our galaxy ( because ( 10 < sup > 0. 4 </ sup >)< sup >(− 20. 5 -(− 25. 5 ))</ sup >

A quasi-stellar radio source (" quasar ") is a very energetic and distant active galactic nucleus.

While the nature of these objects was controversial until as recently as the early 1980s, there is now a scientific consensus that a quasar is a compact region in the center of a massive galaxy surrounding its central supermassive black hole.

Quasars show a very high redshift, which is an effect of the expansion of the universe between the quasar and the Earth.

The highest redshift quasar known () is ULAS J1120 + 0641, with a redshift of 7. 085,

Several dozen nearby large galaxies, with no sign of a quasar nucleus, have been shown to contain a similar central black hole in their nuclei, so it is thought that all large galaxies have one, but only a small fraction emit powerful radiation and so are seen as quasars.

The Chandra X-ray Observatory | 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.

Hence the name ' QSO ' ( quasi-stellar object ) is used ( in addition to ' quasar ') to refer to these objects, including the ' radio-loud ' and the ' radio-quiet ' classes.

This means that it is possible that most galaxies, including our own Milky Way, have gone through an active stage ( appearing as a quasar or some other class of active galaxy depending on black hole mass and accretion rate ) and are now quiescent because they lack a supply of matter to feed into their central black holes to generate radiation.

A multiply imaged quasar is a quasar that is undergoing gravitational lensing, resulting in double, triple or quadruple images of the same quasar.

This triple quasar has a red shift of z = 2. 076, which is equivalent to 10. 5 billion light years.

Another example of a triple quasar formed by lensing is PG1115 + 08.

These are two different quasars, and not the same quasar that is gravitationally lensed.

A microquasar is a smaller cousin of a quasar that is a radio emitting X-ray binary, with an often resolvable pair of radio jets.

The collecting area required to constrain Δα / α to the current level of quasar constraints is on the order of 100 square kilometers, which is economically impracticable at the present time.

Shimmins use lunar occultations to determine a precise position for the quasar 3C 273 and deduce that it is a double source,

Artist's rendering of ULAS J1120 + 0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun.

If this particular quasar and our galaxy could be seen side by side at the same distance, the quasar would be 5 magnitudes ( or 100 times ) brighter than our galaxy.

The term quasar was coined by Chinese-born U. S. astrophysicist Hong-Yee Chiu in 1964, in Physics Today, to describe these puzzling objects:

In 1979 the gravitational lens effect predicted by Einstein's General Theory of Relativity was confirmed observationally for the first time with images of the double quasar 0957 + 561.

The first true triple quasar was found in 2007 by observations at the W. M. Keck Observatory Mauna Kea, Hawaii.

When two quasars are so nearly in the same direction as seen from Earth that they appear to be a single quasar but may be separated by the use of telescopes, they are referred to as a " double quasar ", such as the Twin Quasar.

results still need to be checked by independent analysis, using quasar spectra from different telescopes.

have used Markov Chain Monte Carlo methods to investigate the algorithm used by the UNSW group to determine from the quasar spectra, and have found that the algorithm appears to produce correct uncertainties and maximum likelihood estimates for for particular models.

* ' To the quasar ', a song by Dutch project-band Ayreon is about quasar 3C 273.

If this is the case, there must be a population of objects not beamed towards us, and, since we know the lobes are not affected by beaming, they would appear as radio galaxies, provided that the quasar nucleus is obscured when the source is seen side-on.

Complementing and in agreement with these simulation studies by Peratt was an analytical model of a plasma quasar mechanism by Eric Lerner.

Originally discovered by Dennis Walsh, Bob Carswell, and Ray Weymann in 1979, the double image of this quasar is caused by a galaxy positioned between it and the Earth.

However, a team of astronomers at the Harvard-Smithsonian Center for Astrophysics led by Rudolph Schild studied the quasar and found that during the period between September 1994 and July 1995 the two images appeared to have no time delay ; changes in the brightness of the two images occurred simultaneously on four separate occasions.

In " Time Keeps on Slippin '", Fry moves the stars to write a love note to Leela, but the message is removed by a quasar before she can read it.

Thus it can be inferred that any major differences between quasar spectra will be caused by interaction with atoms along the line of sight.

However, by looking at the more easily observed quasars in the nearby universe, and assuming that the luminosity function ( number of quasars as a function of luminosity ) during reionization will be approximately the same as it is today, it is possible to make estimates of the quasar populations at earlier times.

Such studies have found that quasars do not exist in high enough numbers to reionize the IGM alone, saying that " only if the ionizing background is dominated by low-luminosity AGNs can the quasar luminosity function provide enough ionizing photons.

This quasar furnished the elegant proof of the role of scattering due to the ISM, or interstellar scintillation, by showing a time delay in arrival between the signal at widely-spaced telescopes ( in the USA and Netherlands ).

His research on quasars has included development of the relativistic blast wave model for variability, introduction of reverberation mapping to analyze variable emission line profiles, the two-phase model for quasar emission line regions, and the development of the theory of coronae and winds from accretion disks.

On 22 July 2011, a report described the discovery of a gigantic cloud of water vapor, containing " 140 trillion times more water than all of Earth's oceans combined ," around a quasar located 12 billion light years from Earth.

In the formation known as Einstein's Cross, four images of the same distant quasar appear around a foreground galaxy due to strong gravitational lensing

Four images of the same distant quasar appear around a foreground galaxy due to strong gravitational lensing.

HE0450-2958 has no visible host galaxy ( a galaxy surrounding the quasar ) detected around it.

However, no galaxy was seen around the quasar itself ( figure, middle ), leading the authors to speculate

A blazar is a very compact quasar ( quasi-stellar object ) associated with a presumed supermassive black hole at the center of an active, giant elliptical galaxy.

Two of the papers — from groups in Cambridge, Massachusetts and Cambridge, England -- suggested that the quasar was a supermassive black hole that had been ejected from the center of the nearby, disturbed galaxy, either by gravitational radiation recoil or by an interaction involving three black holes.

NLS1's are believed to have abnormally small black holes ; since black hole size is strongly correlated with galaxy size, the host galaxy of the quasar should also be abnormally small, explaining why it had not been detected by Magain et al.

( 2007 ) observed the X-ray emission from the quasar and used it to estimate the mass of the black hole.