NoelC wrote:If that thing happened to be pointed at us, would it seem to have similar characteristics to a quasar? Asked another way, are the quasars we see likely to be chance alignment with such beams from other objects/galaxies?
Also, it's intriguing to think that the energy level in that beam may be strong enough to sterilize all the planets that happen to pass through it. Am I off base in this thinking? Or could some hypothetical civilization whose star is circling that galaxy be seeing that beam growing ever nearer, thinking they have but a short time to live?
I probably know just enough about jets to get me in trouble, but here's my understanding.
First, jets are nasty, very nasty. A gamma ray burst (GRB) is theorized to be an on-axis emission from a jet during a super nova (a star mind you, not a SMB), and this GRB is considered to be dangerous for Earth if one popped off in our galaxy we were in this "collimated" beam. My thought is an SMB jet could more easily be deadly on a galactic distance scale. However the details depend on how active the acretion disk is, and the energy of the accelarated particles and the associated electromagnetic beam. I suspect if we can visually see a deadly jet's synchrotron radiation, it might already be too late as the death blow likely would be initiated first with the high-energy radiation, e.g. gamma rays. With that said, the follow up punch of vast quantities of high energy particles could be the final blow to the planet, but would there be any life around at that time is another question. Certainly, a planet could survive if the particle beam energy was low enough. Imagine a long-lived auroral display driven by a jet of particles 10's of thousand light years away!
Second, an angular energy distribution of radiation is also theorized (I'm assuming the same applies to AGN). The on-axis, high-energy radiation (gamma ray) gives way to lower energies as propagation angles increase away from on-axis beam. So, when we observe a quasar (most have a dominant radio frequency component, I believe), we are most likely NOT looking down the bore.
You may find this site
interesting. It's a long discussion about GRB's. It also discusses jets associated with supernovae and black hole formation. I don't think super massive BHs are mentioned (I haven't read the whole thing), but I'm willing to consider jets, jet formation to be very similar, if not the same. I mean the recipe for extreme jets seem to be high rotational speeds, very strong magnetic fields, and an acretion disk surrounding a very massive component, e.g black hole or neutron star.