منابع مشابه
Determination of optical positions for 23 extragalactic radio sources
AB S TRACT The optical counterparts of 23 extragalactic radio sources, of which 13 are in the southern hemisphere, have been observed by three telescopes equipped with CCDs. By reference to the Astrographic/Tycho (ACT) Reference, Carlsberg Meridian (CMC), Positions and Proper Motions (PPM), Hipparcos (HIP) and Lick Northern Proper Motion (NPM) catalogues, the positions of the 23 objects have be...
متن کاملEstimating the Number of Wideband Radio Sources
In this paper, a new approach for estimating the number of wideband sources is proposed which is based on RSS or ISM algorithms. Numerical results show that the MDL-based and EIT-based proposed algorithm havea much better detection performance than that in EGM and AIC cases for small differences between the incident angles of sources. In addition, for similar conditions, RSS algorithm offers hi...
متن کاملestimating the number of wideband radio sources
in this paper, a new approach for estimating the number of wideband sources is proposed which is based on rss or ism algorithms. numerical results show that the mdl-based and eit-based proposed algorithm havea much better detection performance than that in egm and aic cases for small differences between the incident angles of sources. in addition, for similar conditions, rss algorithm offers hi...
متن کاملThe Reconciliation of Optical and Radio Positions
Reconciliation of optical and radio postions is basically a matter of reconciling positional reference systems. For example, the question of whether, for a given source, there is a real physical off-set between the optical and radio centroid at a given frequency cannot be properly inves tigated until the reference systems have been securely established. In the more sophisticated case of the co...
متن کاملRadio astrometry with chromatic AGN core positions
Aims. The effect of frequency-dependent AGN core positions (“core-shifts”) on radio Very Long Baseline Interferometry (VLBI) global astrometry measurements is investigated. Methods. The basic equations relating to VLBI astrometry are reviewed, including the effects of source structure. A power-law representation of core-shifts, based on both observations and theoretical considerations of jet co...
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ژورنال
عنوان ژورنال: Australian Journal of Physics
سال: 1968
ISSN: 0004-9506
DOI: 10.1071/ph680065