Quasars

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Quasar is a short form word which is stands for Quasi-Stellar radio source also abbreviated as QSO. These were named as such because they were first observed by early radio astronomers.They were appeared as faint star like dots in the night sky and astronomers at that time did not have any idea about what they are.

 
Artistic illustration of a Quasar (Image Credits: ESO/M. Kornmesser)

Astronomers observed extremely high red shifted values from these objects and this leads to determine that they were extremely luminous and very distant Active Galactic Nuclei also abbreviated as AGN. There are different types of AGNs in the universe according to the observers point of view. Quasars are one of the types of AGNs. They are very bright, distant and active super massive black holes which have mass of millions or billions of solar masses surrounded by host galaxy.

 
Different types of AGNs according to the observers point of view 
(Image Credits: ESO/L. Calçada and M. Kornmesser)
 

Although they are the most luminius objects in the known universe, you cannot see them with your naked eyes. The reason is, they are very fainter and very distant from the Earth. The brightest quasar in the optical range is named as QSO 3C273. This was the first quasar which was discovered in early 1960's by Allan Sandage. It has apparent magnitude of 12.9. It is 2.5 billion light years away from us. Objects with apparent magnitude of 8 or larger are harder to see from the naked eye. Both optical and radio telescopes are using to observe them.

 
QSO 3C 273 is the first quasar observed by the Allan Sandage in early 1960's 
(Image Credits:WFPC2 image: NASA and J. Bahcall (IAS);
ACS image: NASA, A. Martel (JHU), H. Ford (JHU), M. Clampin (STScI), G. Hartig (STScI),
G. Illingworth (UCO/Lick Observatory), the ACS Science Team and ESA)  

As you can see in the image the quasar emits jets of material and massive amount of radiation through out the universe. When the higher rate of matter falling in to the super massive black hole, the stronger magnetic fields may occur.

 
High energy jets released by QSO 3C 273
(Image credits: Komugi et al., NASA/ESA Hubble Space Telescope)

Due to these powerful magnetic fields, quasar's powerful jets or bright corona can occur. The black hole coronas are a regions of diffuse hot gas that lie above and bellow a much denser disk of material swirling around the black hole. These black hole coronas threaded with stronger magnetic fields.

 
Artistic illustration of denser disk of material swirling around the black hole 
(Image Credits: Pixabay.com)

Quasars are kind of galaxies which has highly active galactic nuclei. Due to the high radiation and shock waves, these galaxies does not believe to exist life and star formation. But there is a research going on about the quasar jets could stimulate to form galaxies at the end of their jets.

 
Quasar jets could stimulate to form galaxies at the end of their jets. 
(Image Credits: ESO/NASA/ESA/D. Elbaz/L. Calçada) 
 




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