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In article ,
Michael Sandell writes: http://laserstars.org/V1982/table1.html gives proper motions and apparent redshifts for 30 quasars. Uncertainties are too large to be useful; results look consistent with zero. VLBA ought to be four or so orders of magnitude better, which is what one would need to say anything meaningful. -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.) |
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A more reliable source of information about quasar proper motion
than http://laserstars.org is: Quasar Apparent Proper Motion Observed by Geodetic VLBI Networks D. S. MacMillan 30 Sep 2003 The 10th Anniversary of the VLBA http://arxiv.org/abs/astro-ph/0309826 This a fascinating field where quasars are convenient reference beams for using VLBI to measure the movement of continents, to millimetre accuracy. The observations span 1980 to 2002 and they do find proper motion. The trick is to be sure that the core is moving, not the lobes or jets - and it seems that this cannot be shown from these observations. Steve, I agree that any tired light theory based on em radiation interacting with the IGM as an inhomogeneous medium would need to meet tight constraints on scattering and blurring. My theory is not detailed enough that I can be sure that this requirement would be met. - Robin http://astroneu.com |
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In article , "Robin
Whittle" writes: A more reliable source of information about quasar proper motion than http://laserstars.org is: Quasar Apparent Proper Motion Observed by Geodetic VLBI Networks D. S. MacMillan 30 Sep 2003 The 10th Anniversary of the VLBA http://arxiv.org/abs/astro-ph/0309826 This a fascinating field where quasars are convenient reference beams for using VLBI to measure the movement of continents, to millimetre accuracy. The accuracy of VLBI is very high. One has to correct for continental drift when doing astrometry or, as you mention, vice versa, and the fact that the speed of rotation of the Earth slows down in the springtime since the leaves in the trees in the northern hemisphere increase the Earth's moment of inertia. The observations span 1980 to 2002 and they do find proper motion. The trick is to be sure that the core is moving, not the lobes or jets - and it seems that this cannot be shown from these observations. As I said in another post, no-one says that quasars should have no proper motion. Rather, Arp's scenario makes a rather clear prediction as to the amount of proper motion, and one can compare this to observations. One doesn't really have to worry about the quasars slowing down etc if one looks at things statistically. In Arp's scenario, proper motion should be away from the galaxy of origin, and should decrease with the distance of the galaxy of origin. In the conventional scenario, proper motion will be random with respect to the galaxies Arp claims the quasars are ejected from, both with respect to direction and with respect to the magnitude of the proper motion. Steve, I agree that any tired light theory based on em radiation interacting with the IGM as an inhomogeneous medium would need to meet tight constraints on scattering and blurring. My theory is not detailed enough that I can be sure that this requirement would be met. Apart from the arguments against tired-light theories, one also has to ask the question whether there is any real motivation to pursue these at all. |
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Steve Willner wrote:
Michael Sandell writes: http://laserstars.org/V1982/table1.html gives proper motions and apparent redshifts for 30 quasars. Uncertainties are too large to be useful; results look consistent with zero. VLBA ought to be four or so orders of magnitude better, which is what one would need to say anything meaningful. These figures are consistent with almost any hypothesis. They could all be zero or they could be moving consistent with the Arp-Narlikar model. In another post Robin Whittle wrote: A more reliable source of information about quasar proper motion than http://laserstars.org is: Quasar Apparent Proper Motion Observed by Geodetic VLBI Networks D. S. MacMillan 30 Sep 2003 The 10th Anniversary of the VLBA http://arxiv.org/abs/astro-ph/0309826 These figures are about two orders of magnitude less than the other ones and therefore probably correspondingly more accurate. For lower redshifts and a few higher ones they show 0.1 to 0.4 mas/year, i.e. about 0.0001 - 0.0004 "/year. This is still an order of magnitude more than the Arp-Narlikar model would require. Therefore the suggestion that quasar motion should be observed but has not been if quasars are at non-cosmological distances must firmnly be rejected. -- Ray Tomes http://ray.tomes.biz/ http://www.cyclesresearchinstitute.org/ |
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