3C 147 (B0538+498) is a compact steep-spectrum (CSS)

quasar A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...

that was discovered in 1964. It is located in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Auriga not far in the sky from the 5th magnitude star Omicron Aurigae. The "distance" of a far away galaxy depends on the distance measurement used. With a

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

of 0.545, light from this active galaxy is estimated to have taken around 5.1

billion Billion is a word for a large number, and it has two distinct definitions: * 1,000,000,000, i.e. one thousand million, or (ten to the ninth power), as defined on the short scale. This is now the most common sense of the word in all varieties of ...

years to reach Earth. But as a result of the

expansion of the Universe The expansion of the universe is the increase in proper length, distance between Gravitational binding energy, gravitationally unbound parts of the observable universe with time. It is an intrinsic and extrinsic properties (philosophy), intrins ...

, the present (co-moving) distance to this galaxy is about 6.4 billion

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s (1974 M pc). Very Long Baseline Array (VLBA) observations have identified a complex central region that is dominated by two bright components, A and B. The separation between the two central components of the source seems to be increasing with an apparent velocity ( superluminal motion) of 1.2 ± 0.4 c. 3C 147 is one of four primary calibrators used by the

Very Large Array The Karl G. Jansky Very Large Array (VLA) is a centimeter-wavelength radio astronomy observatory in the southwestern United States built in the 1970s. It lies in central New Mexico on the Plains of San Agustin, between the towns of Magdalena, Ne ...

(along with 3C 48,

3C 138 3C 138 is a quasar located in the constellation of Taurus. It has a redshift of (z) 0.76. The radio spectrum of this source appears both compact and steep, making it a compact steep-spectrum radio quasar. It is also one of the few 3C objects sho ...

, and 3C 286). Visibilities of all other sources are calibrated using observed visibilities of one of these four calibrators.

References

External links

* Wikisk
image
of 3C 147 (PGC 2355407) {{DEFAULTSORT:3C 147 Quasars 147 Auriga

See also

References

External links