Volume 16, Issue 1
March 1995, pages 1-67
pp 1-36 March 1995
Radio maps at 5 GHz with an angular resolution of 1 to 2 arcsec and a dynamic range ≳ 200:1 are presented for a sample of 45 radio quasars at redshifts between 0.2 and 1.5. The sources were imaged from observations made with the Very Large Array with the aim of investigating the epoch dependence of misalignments and asymmetries in their extended radio structure. Maps of some of the larger radio sources are presented also at a frequency of 1.5 GHz with a typical angular resolution of ≈ 4 arcsec. The radio structure of most of the quasars reported here has been delineated in considerably greater detail than available in the literature.
pp 37-43 March 1995
We present velocity observations, obtained with the E. W. Fick Observatory 0.6 m telescope, of the 7th magnitudeK1 star HR 7112. Our observations show that HR 7112 is a double-line spectroscopic binary system composed of almost equal mass stars with a period of 215.6 days. The orbit has an eccentricitye = 0.142 and the stars orbit each other with a mean semi-major axis distance of approximately 0.4sin(i) AU. The masses of the stars are consistent with the classification as giant stars. Tidal effects are known to circularise the orbits of giant stars and this process is apparently underway in this system.
pp 45-52 March 1995
The effect of internal noise on the response characteristics of nonlinear radial pulsation in polytropic model has been investigated using the equivalent linearization technique. The model of the noise is taken to be δ-correlated with zero mean. Both non-stationary and stationary response characteristics have been computed for various nonlinearity parameters in different polytropes.
pp 53-67 March 1995
A detailed statistical analysis of pulsarcurrent is presented. The conclusions reached are the following: (1) The birthrate of pulsars is about one in 75 ± 15 years. (2) There is evidence forinjection of pulsars into the population of solitary pulsars. Such an injection is particularly pronounced in the magnetic field range 12 < logB < 12.6. (3) This is interpreted as due torecycled pulsars being released into the population. (4) We tentatively conclude that as much as 10 – 15% of all pulsars may have been born and processed in binary systems.
Volume 40 | Issue 4
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