VictorBorun wrote: ↑Mon Jan 18, 2021 9:36 am
Ann wrote: ↑Mon Jan 18, 2021 6:48 am
The jet and the lobe are not directed straight at us, however. If they were, we wouldn't see a jet at all, just a very bright central light source.
For M87 the angle between our line of site and the axis of the jet and the counterjet: 17±3°.
(using apparent component speeds in the jet, 0.21±0.04, and the counterjet, 0.14±0.02$, along with an intensity ratio, 9.5±1.5
https://iopscience.iop.org/article/10.3 ... 357/aaafcc
17°is a small angle I would never have guessed. But that's what they calculate for the counterjet to be almost invisible.
It seems Centaurus A's jets are almost in the plane of the dust gas disk. Does it show that the black hole originates from another galaxy?
This is how I understand it. Centaurus A consists of two colliding galaxies, one larger elliptical galaxy and one smaller spiral galaxy which is being incorporated into the larger elliptical. (Or, okay, we may describe Cen A as one galaxy, but it definitely has two components.)
I'd say that the large elliptical galaxy definitely has a central black hole, and it had that black hole before the galaxy collided with the spiral. The collision has undoubtedly sent a large amount of gas into the black hole of the elliptical galaxy, and this copious sudden gas influx is what has made the black hole of the elliptical galaxy act up and spew out jets.
An interesting question is whether or not the spiral galaxy has a sizable black hole of its own. It may have one, but it also may not. Small local spiral galaxy M33
doesn't have a central black hole, at least not one that can be described as "supermassive" in any way.
But if the spiral galaxy that is colliding with the elliptical galaxy in what is Centaurus A does have a supermassive black hole, it would be interesting to see what would happen if the black holes were to collide. I guess that chances are slim that that would happen, provided the small spiral galaxy has a supermassive central black hole in the first place.