The discussion revolves around the potential implications of galactic redshift anomalies, particularly those associated with quasars as proposed by Halton Arp, on the Big Bang Theory (BBT). Participants explore the validity of Arp's claims and the nature of quasars, examining whether these anomalies challenge mainstream cosmological models.
Participants express a range of views, with no consensus reached on the implications of Arp's claims for mainstream theories. Some defend the BBT against Arp's assertions, while others highlight unresolved questions and the need for further examination of the evidence.
The discussion highlights limitations in the statistical analyses of redshift anomalies and the dependence on definitions of redshift and distance. Some claims remain unresolved, particularly regarding the nature of quasars and their relationship to host galaxies.
Nereid said:Welcome to Physics Forums, lezardo!
Halton Arp's 'discoveries' are controversial.
Except that the quasars seem to be just active galaxy nuclei with normal galaxies around them (the 'quasar host', as it's called) ... at distances from us consistent with their redshifts (i.e. vastly further away than the galaxy Arp claims they've been ejected from). Further, if there were some kind of interaction, how come there's no material - in the bridge - with a redshift in between that of the galaxy and the quasar?Galoot said:Some astronomers, such as Toomre, have postulated that quasars are the result of galactic collisions. I thought that this explanation of quasars has become relatively well accepted, at least initially. If so, wouldn't these galactic collisions be consistent with Arp's theories that the quasar and adjacent galaxy are physically connected?
I'm not sure if I follow. As you say, quasars are always (as far I know) been found associated with a host galaxy. For the quasars in Alp's atlas, the only nearby (visually) galaxies which could serve as the host galaxies (and which likely are due to the observed dust bridges) are ones with dramatically different redshifts. How does that show Alp to be wrong? Alp and Burbrige even claimed just a year ago to have found a quasar with larger redshift embedded in, or possibly immediately in front of, the galaxy NGC 7319. How could a quasar so far away (if it is far away) be seen clearly through the dust of the central core of a galaxy?Nereid said:Except that the quasars seem to be just active galaxy nuclei with normal galaxies around them (the 'quasar host', as it's called) ... at distances from us consistent with their redshifts (i.e. vastly further away than the galaxy Arp claims they've been ejected from).
That assumes what is the scope and nature of the cause of the quasar redshift. Quasars are thought to be rather small, on the order of a singularity up to about the size of our solar system, from what I've read. If the cause of the redshift is a halo of diffuse plasma around the quasar, as postulated by Brynjolfsson, then the light emitting from the compact quasar could be shifted without affecting the light from dust bridges many hundreds or thousands of light years away.Further, if there were some kind of interaction, how come there's no material - in the bridge - with a redshift in between that of the galaxy and the quasar?
The confusion here is 'host'; the host galaxies of quasars (those that have been reliably observed, to date) are very, very close (on the sky) to the photocentre of the quasar ... mostly <2" ... and they surround the photocentre on all sides.Galoot said:I'm not sure if I follow. As you say, quasars are always (as far I know) been found associated with a host galaxy. For the quasars in Alp's atlas, the only nearby (visually) galaxies which could serve as the host galaxies (and which likely are due to the observed dust bridges) are ones with dramatically different redshifts. How does that show Alp to be wrong? Alp and Burbrige even claimed just a year ago to have found a quasar with larger redshift embedded in, or possibly immediately in front of, the galaxy NGC 7319. How could a quasar so far away (if it is far away) be seen clearly through the dust of the central core of a galaxy?Nereid said:Except that the quasars seem to be just active galaxy nuclei with normal galaxies around them (the 'quasar host', as it's called) ... at distances from us consistent with their redshifts (i.e. vastly further away than the galaxy Arp claims they've been ejected from).
Indeed. However that would take us beyond the scope of this section of PF - Brynjolfsson's ideas are very clearly non-mainstream (and, I suspect, strongly inconsistent with many many more very good observational and experimental results than Arp's are).That assumes what is the scope and nature of the cause of the quasar redshift. Quasars are thought to be rather small, on the order of a singularity up to about the size of our solar system, from what I've read. If the cause of the redshift is a halo of diffuse plasma around the quasar, as postulated by Brynjolfsson, then the light emitting from the compact quasar could be shifted without affecting the light from dust bridges many hundreds or thousands of light years away.