- Następna wiadomość (według wątku): superluminal motions & H_0 - comments from Ajk - Bartek's IAP talk
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Witam wszyscy, Andrzej Kus is sceptical about using superluminal motions for estimating (local) cosmological parameters. Good :). Andrzej K - please correct me if i'm wrong, but what i understand of your arguments are something like: -> jets are bent, not systematically, nobody knows why, sometimes helical, very complex -> superluminal expansion speed is highly variable -> depends on which blobs are in which place, some blobs are fast, some are slow --> especially in mm data -> on month scale changes very rapidly - some blobs just stop for some time, and then start up again. My initial reaction is that in a statistical sample these should average out, provided that the errors are random and symmetrically distributed. Alternatively: can we try to statistically correct for this? Given that blobs stop and then start again, or change direction, but are only *detected* when they are moving superluminally, then it would seem to me that the true average speed is slower than estimated from the doppler factor. Most practical cosmology is about statistical corrections - it requires careful modelling and correct statistical analysis, but it can be done. Is it reasonable to use the observational data which *shows* the erratic behaviour of these objects to statistically model this? If yes, then we would have the necessary correction factor. Anyway, here's a link to Bartek's IAP talk: http://www2.iap.fr/Conferences/Colloque/col2004/Docs/20040629_Lew.pdf Andrzej K suggested that Bartek give a presentation on this (a Monday talk?) - seems a fine idea to me, and doesn't require much preparation from Bartek's side (except to take account of Andrzej's comments). pozdr boud -------------- następna część --------- Błędnie zakodowany tekst został usunięty... Plik: message.footer Url: <http://cosmo.torun.pl/pipermail/cosmo-torun/attachments/20040827/0622e10a/attachment.ksh>

- Następna wiadomość (według wątku): superluminal motions & H_0 - comments from Ajk - Bartek's IAP talk
**Wiadomości posortowane według:**[ daty ] [ wątku ] [ tytułu ] [ autora ]

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