Relativistic Beaming and the Intrinsic Properties of Extragalactic Radio Jets

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dc.creatorCohen, M. H.
dc.creatorLister, M. L.
dc.creatorHoman, D. C.
dc.creatorKadler, M.
dc.creatorKellermann, K. I.
dc.creatorKovalev, Y. Y.
dc.creatorVermeulen, R. C.
dc.date2006-11-20
dc.date.accessioned2026-07-07T10:20:55Z
dc.date.available2026-07-07T10:20:55Z
dc.descriptionRelations between the observed quantities for a beamed radio jet, apparent transverse speed and apparent luminosity (beta_app,L), and the intrinsic quantities, Lorentz factor and intrinsic luminosity (gamma,L_o), are investigated. The inversion from measured to intrinsic values is not unique, but approximate limits to gamma and L_o can be found using probability arguments. Roughly half the sources in a flux density--limited, beamed sample have a value of gamma close to the measured beta_app. The methods are applied to observations of 119 AGN jets made with the VLBA at 15 GHz during 1994-2002. The results strongly support the common relativistic beam model for an extragalactic radio jet. The (beta_app,L) data are closely bounded by a theoretical envelope, an aspect curve for gamma=32, L_o= 10^25 W/Hz. This gives limits to the maximum values of gamma and L_o in the sample: gamma_max about 32, and L_o,max ~ 10^26 W/Hz. No sources with both high beta_app and low L are observed. This is not the result of selection effects due to the observing limits, which are flux density S>0.5 Jy, and angular velocity mu<4 mas/yr. Many of the fastest quasars have a pattern Lorentz factor gamma_p close to that of the beam, gamma_b, but some of the slow quasars must have gamma_p<<gamma_b. Three of the 10 galaxies in the sample have a superluminal feature, with speeds up to beta_app about 6. The others are at most mildly relativistic. The galaxies are not off-axis versions of the powerful quasars, but Cygnus A might be an exception.
dc.description12 pages, 9 figures, 1 table, accepted for publication in the Astrophysical Journal
dc.identifierhttps://arxiv.org/abs/astro-ph/0611642
dc.identifierhttp://arxiv.org/abs/astro-ph/0611642
dc.identifierAstrophys.J.658:232-244,2007
dc.identifierdoi:10.1086/511063
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/175006
dc.subjectAstrophysics
dc.titleRelativistic Beaming and the Intrinsic Properties of Extragalactic Radio Jets
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