On Friday, January 20, 2017 at 8:44:02 AM UTC-8, Martin Brown wrote:
On 19/01/2017 03:53, wrote:
Example object, Pictor A
http://chandra.harvard.edu/photo/2016/pictora/

in particular, the x ray Chandra image:
http://chandra.harvard.edu/photo/201...ctora_xray.jpg

Question 1:

Has anyone proposed any model that describes a mechanism to produce
a single BH jet, or, alternating BH jets (e.g. the jet shoots one
way for a while, then the other way for a while, alternating back
and forth)?


However time of flight considerations could mean that there hasn't yet
been time for the light from the more distant hotspot of two to reach us=

in the case of a source where the jet is almost pointing at us.


Regards,
Martin Brown

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Thanks and good point, time of flight, as the jets are million light year l=
ong, we would see the jet toward us first, and the jet away from us second,=
with perhaps 2 million years to who knows, 10 million years from jet emerg=
ence to our current view which could be anywhere along that entire evolutio=
n. The thing is, I've seen a lot of pictures, but it's always presented th=
at the hot spot is coming toward us.

My point is that there ought to be 50% of these objects where the hot spot =
we observe is the hot spot of the receding jet. I understand beaming and h=
ow we might not observe the receding jet vs the jet coming at us. But, the=
hot spot should be relatively stationary and glowing, so that we see both =
hot spots if there are two to be seen. And if they shut down so, we ought =
to see half of them with the receding hot spot and no observed jet because =
it is receding.

I don't recall seeing a hot spot without a jet feeding it such that the hot=
spot is supposed to be the receding hot spot, and no jet is observed due t=
o alignment. Is there an image of this out there that anyone knows?

rt