A direct determination of linear-size evolution of elliptical radio galaxies

Nature ◽  
1987 ◽  
Vol 328 (6130) ◽  
pp. 500-501 ◽  
Author(s):  
M. J. A. Oort ◽  
P. Katgert ◽  
R. A. Windhorst
Keyword(s):  
Direct Determination ◽  
Radio Galaxies ◽  
Linear Size ◽  
Size Evolution

scholarly journals On the Unification of Radio Galaxies and Quasars

1994 ◽  
Vol 159 ◽  
pp. 501-501
Author(s):  
Krzysztof T. Chyzy
Keyword(s):  
Radio Galaxies ◽  
Linear Size ◽  
Expansion Velocity ◽  
Evolutionary Patterns ◽  
Consistency Test ◽  
Radio Structure ◽  
Size Evolution ◽  
The Asymmetry ◽  
Asymmetry Parameters ◽  
Independent Parameters

A comparison of the projected linear size evolution of extended quasars and radio galaxies are often used as a test of the radio galaxy - quasar unification schemes. If both the mentioned categories of radio sources differ to an observer only due to the various viewing directions, then their radio linear sizes are expected to evolve with redshift in the same way (Gopal-Krishna & Kulkarni, 1992). However, apart from the simplest linear size parameter L we can still determine two independent parameters assessing the asymmetry of the radio structure: Q - the arm lengths ratio; M - misalignment, which measures the apparent bending, and defined as the ratio of the displacement of the core from the source axis to the linear size. The asymmetry parameters Q and M can also be a powerful tool in the consistency test for the orientation based unification scheme as their evolutionary patterns should be the same for radio galaxies and quasars. Contrary to the linear size, they are not sensitive to the simple homological rescaling of the whole structure and hence to the age or expansion velocity of the structure.

scholarly journals Luminosity Selection Effects and Linear Size Evolution in the Quasar/Galaxy Unification Scheme

1998 ◽  
Vol 51 (1) ◽  
pp. 143
Author(s):  
A. A. Ubachukwu ◽  
J. N. Ogwo
Keyword(s):  
High Redshift ◽  
Radio Galaxies ◽  
Linear Size ◽  
Selection Effects ◽  
Size Evolution

The implications of linear size evolution and luminosity selection effects in the quasar/galaxy unification scheme have been investigated. We show that both radio galaxies and quasars undergo similar size evolution above some low redshift cut-off zc = 0·2–0·3. However, this evolution can be attributed largely to the strong luminosity selection effects present in the sample. We also observe that there is a marked difference in the luminosity–redshift slope between low and high redshift sources, which may be responsible for the conflicting results in the literature as to whether or not radio galaxies and quasars have similar linear size versus luminosity/redshift relationships. Our present result seems consistent with the quasar/galaxy unification scheme in which the two classes of object are expected to have similar linear size versus luminosity/redshift relationships.

The Direct Determination of I131 in Heterogeneous Fecal Specimens

1961 ◽  
Vol 41 (4) ◽  
pp. 380-384 ◽  
Author(s):  
Arthur F. Dratz ◽  
James C. Coberly
Keyword(s):  
Direct Determination

A New Method for Direct Determination of the Recoilless Fraction with Application to Magnetic Nanoparticles

2002 ◽  
Vol 721 ◽  
Author(s):  
Monica Sorescu
Keyword(s):  
Room Temperature ◽  
Average Particle Size ◽  
Direct Determination ◽  
Average Particle ◽  
Lattice Method ◽  
Recoilless Fraction ◽  
Single Room ◽  
Magnetite Particles ◽  
Physical Mixtures

AbstractWe propose a two-lattice method for direct determination of the recoilless fraction using a single room-temperature transmission Mössbauer measurement. The method is first demonstrated for the case of iron and metallic glass two-foil system and is next generalized for the case of physical mixtures of two powders. We further apply this method to determine the recoilless fraction of hematite and magnetite particles. Finally, we provide direct measurement of the recoilless fraction in nanohematite and nanomagnetite with an average particle size of 19 nm.

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