Volume 7, Issue 2
June 1986, pages 53-129
pp 53-57 June 1986
From the experimentally measured (p,n) cross-sections for92,94Zr,93Nb,95,96,98Mo,103Rh,107,109Ag,110Pd,115In,117,122Sn nuclides, for proton energies below 7 MeV, thermonuclear reaction rates in the temperature range 1≤T9≤5(T9=109 K) have been extracted. These reaction rates have been fitted to a three parameter empirical expression proposed by Fowler.
pp 59-70 June 1986
Cosmological scenarios with massive unstable neutrinos are discussed. Restrictions on the mass and the lifetime of the unstable neutrino are derived from (a) age and mass density of the universe and (b) the growth of primordial fluctuations. It will not be possible to accommodate unstable neutrinos with masses above ∼ 1 ke V in standard cosmology unless they have exceedingly small lifetime: Τ <5 × 108 s.
pp 71-75 June 1986
The massive and active galaxies in the core of the Virgo Cluster were shown in 1968 to be aligned on either side of M 87, along the direction of the jet and counter-jet. Recent observations confirm the significance of this alignment by showing that the brightest X-ray sources, including additional large galaxies, define the same line.
Detailed X-ray maps of M 86 show that this galaxy, which is part of the alignment, is probably blown by a wind from M 87 due to its close alignment with the jet. But the large radio E galaxy, M 84, which is 1.4 degrees away from M 87, andexactly along the line of the jet, is shown by the compression of its X-ray isophotes to be actually moving out along the line of the jet. This evidence furnishes rather spectacular support for the earlier conclusion that M 84 had originated as a proto-galaxy within M 87 and had been ejected out along the line of the jet.
pp 77-81 June 1986
Quasars found from objective prism searches have been reported to show no association with galaxies in the Virgo Cluster. A simple analysis here shows significant association of the brightest of these quasars with core galaxies in the Virgo Cluster.
pp 83-98 June 1986
Places of formation have been derived for a sample of 23 Cepheids with well-determined atmospheric abundances in an attempt to study the chemical inhomogeneities in the local interstellar medium. The abundance data available for the sample Cepheids is compiled and critically reviewed to adopt the most reliable esimates. We find that the most conspicuous irregularity in the metallicity is exhibited by stars that are born in the local arm or in the interarm region. We propose a scenario to explain these local variations in terms of supernova-induced star formation in interstellar gas enriched by massive stars formed in the density wave.
pp 99-103 June 1986
It is shown that the luminosity-volume test for optically selected objects has an in-built bias towards increasing the average value ofV/Vm above the Euclidean value of 1/2. A more satisfactory bias-free statistic is suggested in the form of In (V/Vm), The result of applying the test to a sample from the Bright Quasar Survey (BQS) shows that the local hypothesis of quasars is consistent with the data.
pp 105-112 June 1986
A radio continuum map of a 1°5 X 1°5 region in the galactic plane nearl = 54° is presented at 49 cm with a resolution of 100 arcsec X 200 arcsec. The shell source G 54.4 - 0.3 has the characteristics of a supernova remnant while the second large ring structure G 53.9 + 0.3 is a Hn ring consisting of W 52 and several small-diameter thermal sources. One of the twelve small-diameter sources (G 54.73 + 0.61) has a spectral index⇏ -1.6.
pp 113-118 June 1986
Coordinates of polar faculae have been measured and processed using daily photoheliograms of the Kislovodsk Station of the Pulkovo observatory with the final goal of studying their latitude distribution during the solar cycles 20–21. The results obtained are as follows:
The first polar faculae emerge immediately after the polarity inversion of the solar magnetic field at the latitudes from 40° to 70° with the average ‡-55°.
The zone of the emergence of polar faculae migrates poleward during the period between the neighbouring polarity inversions of the solar magnetic field. This migration is about 20° for 8 years, which corresponds to a velocity of 0.5 m s-1.
The maximum number of polar faculae was reached at the activity minimum (1975–1976).
The last polar faculae were observed in the second half of 1978 at the latitudes from 70° to 80°.
pp 119-129 June 1986
We present VLA A-array observations at λ20, 6 and 2 cm and B-array observations at λ20 and 6 cm of the quasar B2 1320 + 299, which has a very unusual radio structure. In addition to a component, A, coincident with the quasar, there are two lobes of radio emission, B and C, on the same side of A. These are located at distances of -25 and 50 arcsec respectively from A. The present observations show that A has a flat-spectrum component coincident with the quasar and a weak outer component at a distance of-4 arcsec along PA - 100°. The morphology of B resembles a head-tail type of structure with its tail towards the north-east. The magnetic field lines in component B appear to follow the bend in the tail. Component C exhibits some extension towards the north-west. We discuss the possible nature of B2 1320 + 299 and suggest that while A appears to be an independent source, the relation between B and C, if they are associated at all, is unclear. Deep optical observations are essential to help clarify the situation.
Volume 40 | Issue 4
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