24 research outputs found

    The spectra and energies of classical double radio lobes

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    We compare two temporal properties of classical double radio sources: i) radiative lifetimes of synchrotron-emitting particles and ii) dynamical source ages. We discuss how these can be quite discrepant from one another, rendering use of the traditional spectral ageing method inappropriate: we contend that spectral ages give meaningful estimates of dynamical ages only when these ages are << 10^7 years. In juxtaposing the fleeting radiative lifetimes with source ages which are significantly longer, a refinement of the paradigm for radio source evolution is required. The changing spectra along lobes are explained, not predominantly by synchrotron ageing but, by gentle gradients in a magnetic field mediated by a low-gamma matrix which illuminates an energy-distribution of particles, controlled largely by classical synchrotron loss in the high magnetic field of the hotspot. The energy in the particles is an order of magnitude higher than that inferred from the minimum-energy estimate, implying that the jet-power is of the same order as the accretion luminosity produced by the quasar central engine. This refined paradigm points to a resolution of the findings of Rudnick et al (1994) and Katz-Stone & Rudnick (1994) that both the Jaffe-Perola and Kardashev-Pacholczyk model spectra are invariably poor descriptions of the curved spectral shape of lobe emission, and indeed that for Cygnus A all regions of the lobes are characterised by a `universal spectrum'. [abridged]Comment: LaTeX, 4 figures. To appear in A

    From Clock Synchronization to Dark Matter as a Relativistic Inertial Effect

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    Lecture at BOSS2011 on relativistic metrology, on clock synchronization, relativistic dynamics and non-inertial frames in Minkowski spacetime, on relativistic atomic physics, on ADM canonical tetrad gravity in asymptotically Minkowskian spacetimes, on the York canonical basis identifying the inertial (gauge) and tidal degrees of freedom of the gravitational field, on the Post-Minkowskian linearization in 3-orthogonal gauges, on the Post-Newtonian limit of matter Hamilton equations, on the possibility to interpret dark matter as a relativistic inertial effect connected with relativistic metrology (i.e. clock synchronization) in Einstein GR.Comment: 90 pages. Lecture at BOSS201

    VLA observations of the wide-angle tailed radio source 1313 + 073

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    The authors present VLA observations at 20 and 6 cm of the wide-angle tailed source 1313+073. It has an asymmetric structure with a sharp bend in the eastern tail and a gradual bend in the western. Both tails become diffuse after the bends. The authors explore several models to explain this structure and conclude that the tails bend because of the motion of the parent cD galaxy through the intracluster medium, which is possible if the cluster containing the source is dynamically young. Examination of the optical fields of 26 similar sources shows that in 20 of them the parent galaxies have a fainter companion (by ≡2 mag), or are D, cD or db. This indicates that cannibalism may be important in the formation and powering of such sources

    <span style="font-size:18.0pt;mso-bidi-font-size:12.0pt; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">(<i style="mso-bidi-font-style:normal">Z</i>) 1<span style="font-size:18.5pt; mso-bidi-font-size:12.5pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-ansi-language:EN-US;mso-fareast-language:EN-US; mso-bidi-language:AR-SA">'-Propylbutyl 3-octadecenoate from <i>Fagara budrunga </i>fruits</span></span>

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    122-124Chemical constituents of the Indian medicinal plant Fagara budrunga <span style="font-size:14.5pt; mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="">commonly known as mullilam, have been isolated. In addition to the known compounds a new ester has been obtained. It has been assigned the structure (Z) 1' -propyl butyl 3-octadecenoate <b style="mso-bidi-font-weight: normal">1 from chemical conversions and spectral analysis.</span
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