What Is a Quasar?

What is a Quasar? Many of you were wondering what is a quasar for several times. Here we are going to explain in detail about quasar. Space is one of the most amazing things which human is yet to understand and Quasar is one of those things.

Now let’s come back to what is a Quasar. First of all, they are one of the brightest objects in the Universe except supernova and gamma-ray bursts. In May 1964, in Physics Today, the word “quasar” was first used in a paper by the Taiwanese-born American astrophysicist Hong-Yee Chiu to describe such astronomically mysterious objects. He Said –

So far, the clumsily long name ‘quasi-stellar radio sources’ is used to describe these objects. Because the nature of these objects is entirely unknown, it is hard to prepare a short, appropriate nomenclature for them so that their essential properties are obvious from their name. For convenience, the abbreviated form ‘quasar’ will be used throughout this paper.

Quasar is a very glowing active galactic nucleus (AGN), in which a supermassive black hole with mass extending from millions to billions of times the mass of the Sun is encompassed by a gaseous accretion disk. As gas in the plate falls towards the black hole, energy is discharged as electromagnetic radiation, which can be seen over the electromagnetic range. The force emanated by quasars is colossal: very amazing quasars have radiances multiple times more noteworthy than a galaxy, for example, the Milky Way Galaxy. While quasars are theoretically very bright, without the use of a telescope we can not see any quasars in the night sky. This is because there are more than a billion parsecs away from the closest quasars. So, given their massive luminosities, they appear fairly faint in the sky. They are very compact objects.

Quasars emit radio waves and that’s how they were first discovered. In photographic pictures at noticeable frequencies, they looked like a faint point of light. High-resolution images of quasars, especially from the Hubble Space Telescope, have shown that quasars occur in galaxy centers and that certain host galaxies interact or merge strongly. The properties observed of a quasar depend on several factors such as the mass of the black hole, the rate of accretion of gas, the direction of the accretion disk relative to the observer, the presence or absence of a jet, and the degree of obscuration within the host galaxy by gas and dust.

Artistic Render of ULAS J1342+0928 at redshift z = 7.54

Artistic Render of ULAS J1342+0928 at redshift z = 7.54 ESO/M. Kornmesser / CC BY 

Quasars activity was more common in distant past and they appeared to be found on a very broad range of distances. The peak of their activity was around approximately 10 billion years ago.  The closest known quasar, 730 million light-years away and it is the optically brightest quasar in the sky. The closest active quasar is a further 1,7 billion light-years away from 3C 273. The most far off realized quasar is ULAS J1342+0928 at redshift z = 7.54; light saw from this quasar was radiated when the universe was just 690 million years of age. There are more than 100,000 identified quasars.

Notwithstanding contemplating the quasars themselves, numerous space experts or astronomers use quasars as foundation light sources to examine the mediating cosmic systems and diffuse gas. This is alluded to as “absorption spectroscopy” because the interceding material is distinguished simply because it retains a portion of the quasar’s light as it goes to Earth. Quasars are also among the most distant known objects. Consequently, they enable astronomers to research information of distant galaxies far too faint to be clearly seen.

The quasar emission will last only as long as fuel is sufficient to form an accretion disk. Quasars can consume up to 1000-2000 solar masses of material annually and have average lifetimes of around 100-1000 million years. When their fuel supply has been depleted, the quasar will “sign off” leaving the much weaker host galaxy behind.