What does an active galactic nucleus look like along with its surrounding galaxy (AGN)?
NS-Capture Theory predicts that there are more neutron stars in the Milky Way Galaxy than normal stars and that supernova explosions occur after a neutron star is captured by a regular star and spins up into a fast pulsar in a close binary system and finally the regular star is heated up by the x-rays and its atmosphere is disrupted by the neutron star pulsar and at some point the regular star becomes gravitationally unstable and blows apart driven by the pulsar wind in a supernova explosion and ends up looking like the Crab Nebula.
As described in what an isolated neutron star might look like, we have a concept of what we might be looking for when looking for these neutron stars. One particular discovery in the last few decades is that of an active galactic nucleus (AGN), has been interesting to me, because it seems to be modeled almost exactly like an isolated neutron star that has been floating through the Milky Way for millions of years might look.
I have been looking for a good reference on AGN’s for several years and finally found an online course called Introduction to Active Galaxies, which for me provided the level of technical detail that was appropriate without getting so detailed as to lose the forest in the trees. It is a free course, and I highly recommend spending the time to go through it. There is an associated book, which is a little more up to date: “An Introduction to Galaxies and Cosmology, 2nd Edition”, by Mark H. Jones, et al. The online course material is contained in chapter 3 of this book, which is not free, of course, but I found to be a more than worthwhile investment.
In this course, section 5 provides a model of an active galaxy.
Basically, the model is:
- a central supermassive black hole (SMBH),
- surrounded by an accretion disk,
- with 2 jets emitting from the SMBH, perpendicular to the accretion disk,
- with that whole thing surrounded by a gas and dust torus (same plane as accretion disk),
- and finally 2 radio lobes above and below the plane of the torus by the 2 jets.
Now, this is quite similar to the model of the isolated neutron star referenced above, except the SMBH would be replaced by an isolated NS, with its magnetic pole axis aligned with the jets perpendicular to the accretion disk.
So the idea is that the neutron star sucks in matter from the accretion disk along the magnetic pole lines and emits x-rays in the process. The x-rays in turn light up the material in the lobes and the gas and dust torus.
Since the material collected by the NS is just interstellar material which is what the surrounding galaxy of an AGN contains, it stands to reason that the spectrum would be similar.
Therefore, based on this very rough approximation, NS-Capture predicts that a large number of the x-ray sources, currently identified as AGN’s, will ultimately turn out to be nearby neutron stars within our own Milky Way Galaxy.