Seyfert Galaxies & Quasars: Redshift Differences Explained

[kop442000]

I have read on a NASA website amongst other places that "Many astronomers believe that Seyfert galaxies and high-energy quasars are basically the same type of objects, but we are simply viewing them differently".

But on the same website it also says that "by measuring their redshifts, we find that Seyferts are much closer to us than quasars or blazars."

But if they are the same things, why do we not see find them at the same redshifts? Is it just because Seyferts for example are not energetic enough that we can detect them at high redshifts?

Thank you,
kop442000.

 

[lippyka]

The difference in redshifts has to do with the physical properties of the two types of objects. Seyfert galaxies are usually much less luminous than quasars and blazars, so they appear at lower redshifts. Furthermore, quasars and blazars are powered by accretion onto a supermassive black hole, and this process produces a lot of energy which can be detected from far away. Seyfert galaxies, on the other hand, produce less energy and so can only be seen from closer distances.