NASA's Hubble Space Telescope Spots Celestial Body That Is Three Different Things All At Once

A celestial body called Z 229-15, which lies about 390 million light-years from Earth in the constellation Lyra, is three different objects all at once. So, how do we define it?

Z 229-15 so interesting that one can define it as three different things: sometimes as a Seyfert galaxy, sometimes as an active galactic nucleus (AGN), and sometimes as a quasar. 

Source : NASA

Can you imagine a celestial object which is everything, in one place, all at once? A celestial object called Z 229-15, which lies about 390 million light-years from Earth in the constellation Lyra, is one such celestial body. It is so interesting that one can define it as three different things: sometimes as a Seyfert galaxy, sometimes as an active galactic nucleus (AGN), and sometimes as a quasar. 

Now, a question arises: what exactly is Z 229-15? According to NASA and ESA (European Space Agency), the celestial body is a quasar, an active galactic nucleus, and a Seyfert galaxy all at once, because the three definitions have significant overlap. 

 

The above image shows a spiral galaxy which has two almost-straight arms coming from the left and right of the core. According to the ESA, the arms meet a starry ring around the galaxy's edge. The starry ring is bluish in colour, and has a core which is golden and shining. The galaxy is surrounded by a faint Halo of light. The black background has some small stars, and one bright star with many diffraction spikes. (Photo: NASA/ESA)

What is a Seyfert galaxy?

Seyfert galaxies are galaxies known to have active galactic nuclei, and were named after American astronomer Carl K Seyfert, who discovered them in 1944.

What is an active galactic nucleus?

An active galactic nucleus is a small region at the heart of certain galaxies and is far brighter than the galaxies' stars. These galaxies are called active galaxies. An active galactic nucleus is actually an active supermassive black hole that emits bright jets and winds, and shapes other galaxies, whether they are nearby Seyfert galaxies or extremely distant quasars and blazars. Blazars are active galactic nuclei emitting extremely powerful jets of radiation in the direction of Earth. 

Active galaxies are extremely luminous due to the presence of the active galactic nucleus, or supermassive black at their core. 

When a black hole sucks material towards it, the material does not directly fall into the colossal behemoth, but is drawn into a swirling disk. From the disk, the material is inexorably tugged towards the black hole. 

The reason active galactic nuclei appear extremely bright is that the disk of matter gets too hot, and releases a large amount of energy across the electromagnetic spectrum. 

What is a quasar?

A quasar is a special type of active galactic nucleus, and can be seen as a brilliant beacon of intense light from the centre of a distant galaxy. A quasar is both extremely bright and extremely distant from Earth.

Therefore, when a quasar is located several hundred million light-years from Earth, it is considered to be a nearby quasar. This means that Z 229-15 is relatively local. 

How is Z 229-15 three different objects all at once?

All quasars are active galactic nuclei, but all active galactic nuclei are not quasars. 

Active galactic nuclei can become so bright that the rest of the galaxy cannot be seen, but Seyfert galaxies are active galaxies that host very bright active galactic nuclei or quasars, while the rest of the galaxy is still observable. 

Z 229-15 is three different objects all at once because it is a Seyfert galaxy that contains a quasar, which is a type of active galactic nucleus. This means that Z 229-15 hosts an active galactic nucleus.