Il giorno giovedì 29 novembre 2018 17:48:21 UTC+1, Steve Willner ha scritto:
I can't see how the distance to a quasar can be measured according
to redshift. i.e. Spectral lines generated within a black hole (if
there were such things) will always be gravitationally redshifted
by 100%,

No light escapes from within the event horizon. All observed
emission has to come from outside it.

and spectral lines from matter orbiting the black hole
will be gravitationally redshifted enormously.

The broad lines arise tens to hundreds of light-days from the black
hole. A good reference is at
https://ned.ipac.caltech.edu/level5/...on/frames.html

I leave it to you to calculate the gravitational redshift.

The narrow lines come from even farther from the black hole and show
nearly the same redshift as the broad lines.

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Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA .. for my and your curiosity here we have some easy number about the Readshift and the distribution of galaxies and quasars :
from the CAT VII/250 parent (galaxies) with z (redshift) , ETA 0 , ECC 0.2 , factor space-doupling 1,26 ...: whitin z= 0.01 and 0.0126 (that is 0.01*1.26 ) Number Found Galaxies = 26 ; whitin z=0.0126 and 0.015876 (that is 0.0126*1.26) NumberFG= 58 (Waited = 52) ; whitin z=0.015876 and 0.02 (that is 0.015876 *1.26) NFG= 146 (Waited= 116) ; whitin z=0.02 and 0.0252 (that is 0.02*1.26) NFG= 274 (Waited = 292) ; whitin z= 0.0252 and 0.03175 (that is 0.0252*1.26) NFG= 470 (Waited = 548 )
from the CAT VII/260 ( quasars) for z 0.1135 Number Found Quasars = 37 ; for z0.143 (that is 0.1135*1.26 ) NFQ= 125 (Waited = 74) ; for z0.18 NFQ = 335 (Waited = 250 ) ; for z 0.227 (that is 0.18*1.26 ) NFQ = 865 (Waited =670)
.. so it seems the confirmation that the distribution of quasars is an anomaly ( it increases progressively of 50% with the distance !) and that the Redshift is a good way for measuring the distance like the magnitude is ; but for explain the anomaly we have a suspicion about the meaning of quasars 'escape ( and warm galaxies ?) and the hipothesy of Bigbang .. could the higth temperatures ( frequencies) modify the Redshift ?.. the explication could resolve probabely also the Cosmic BackGround Radiation ..