• Wolfgang Kundt

      Articles written in Journal of Astrophysics and Astronomy

    • The jet of the Quasar 3C 273

      Wolfgang Kundt Gopal-Krishna

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      New observations of the jet in 3C 273 support and refine our earlier interpretation that (i) the mapped jet is 106±0.3 yr old and grows at 0.6 to 0.75 times the speed of light, at an average angle θ of (20 ± 10)‡ with respect to the line of sight; (ii) its twin is not seen yet because arriving signals were emitted when it was some 100.6±0.2 times younger; (iii) the fluid moving in the jet is an extremely relativistice±-pair plasma, of bulk Lorentz factor γ >102; (iv) the beam has swung in projection through some 10‡; and (v) the small excursions (wiggles) of the jet around its average propagation direction result from a self-stabilizing interaction with the nonstatic ambient plasma. All other interpretations of which we are aware depend heavily on the (‘beaming’) assumption that the jet material radiates isotropically in some (comoving) Lorentz frame, an assumption which we consider unrealistic.

    • Dark spots, bubbles, and shells in the lobes of extragalactic radio sources

      Wolfgang Kundt Lakshmi Saripalli

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      Based on maps of the extragalactic radio sources Cyg A, Her A, Cen A, 3C 277.3 and others, arguments are given that the twin-jets from the respective active galactic nucleus ram their channels repeatedly through thin, massive shells. The jets are thereby temporarily choked and blow radio bubbles. Warm shell matter in the cocoon shows up radio-dark through electron-scattering.

    • Is there a black hole among the black-hole candidates?

      Wolfgang Kundt Daniel Fischer

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      None of the tentative black-hole identifications has remained without serious difficulties. As a class, the black-hole candidates differ in no obvious property from neutron-star binaries other than in their estimated high mass. We favour an interpretation of the black-hole candidates as binary neutron stars surrounded by a more or less massive accretion disc

    • The physics of E × B-drifting jets

      Wolfgang Kundt Gopal Krishna

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      E × B-drifting jets have been generally ignored for the past 25 years even though they may well describe all the astrophysical jet sources, both on galactic and stellar scales. Here we present closed-form solutions for their joint field-and-particle distribution, argue that the observed jets are near equipartition, with extremely relativistic, monoenergetic e±-pairs of bulk Lorentz factor γ ≲ 104, and are first-order stable. We describe plausible mechanisms for the jets’ (i) formation, (ii) propagation, and (iii) termination. Wherever a beam meets with resistance, its frozen-in Poynting flux transforms the delta-shaped energy distribution of the pairs into an almost white power law,E2NEE−∫ with ∫ ≳ 0, via single-step falls through the huge convected potential.

  • Journal of Astrophysics and Astronomy | News

    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

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