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  • 1
    Electronic Resource
    Electronic Resource
    Mass discrepancies in galaxies: dark matter and alternatives (1990)
    Springer
    The astronomy and astrophysics review 2 (1990), S. 1-28 
    Details
    ISSN: 1432-0754
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Neutral hydrogen line observations of the extended rotation curves of spiral galaxies imply that there exist significant discrepancies between the luminous and dynamical mass beyond the bright optical discs. This means either that galaxies contain significant quantities of non-luminous matter (matter with a mass-to-light ratio very much higher than that of ordinary stars), or that the law of gravity on the scale of galaxies is not the usual Newtonian inverse square law. Attempts to account for the observed discrepancy in the context of these two explanations are reviewed here with emphasis given to the second and less conventional alternative. It is argued that the standard picture of spiral galaxy halo and disc formation in the context of cold dark matter cannot account for the observed systematics of the discrepancy — notably rotation curves which are seen to be flat and featureless from the bright inner regions where the visible matter dominates the dynamics (in some cases overwhelmingly) to the outer regions where the dark halo dominates. It is demonstrated that in those galaxies with well-observed rotation curves, the discrepancy apparently appears below a critical acceleration. Any dark matter explanation of the discrepancy must account for this fact. Moreover, this would also eliminate empirically motivated modifications of Newton's law in which the deviation from 1/r occurs beyond a fundamental length scale. The suggestion by Milgrom in which the force law becomes essentially 1/r below a critical acceleration (MOND) can account for most of the observed systematics of galaxy rotation curves and, significantly, leads to the observed luminosity-velocity relationship in spiral galaxies (the Tully-Fisher law). Generally covariant theories of gravity which predict this phenomenology in the weak-field limit are described. Although there is not yet a theory which obviously meets all of the requirements for a physically viable alternative to dark matter, a generalized scalar-tensor theory of the form suggested by Bekenstein (phase coupling gravitation) is the currently leading candidate and has the advantage of being testable locally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00873540
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  • 2
    Electronic Resource
    Electronic Resource
    Super-relativistic phase velocities of radio source components (1974)
    [s.l.] : Nature Publishing Group
    Nature 248 (1974), S. 390-392 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A sudden injection of relativistic electrons at the centre of an extended dipolar magnetic field could lead to an apparent faster-than-light expansion of two synchrotron emitting regions. Subsequent injections of electrons would produce components which move outwards along the same ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/248390a0
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  • 3
    Electronic Resource
    Electronic Resource
    More on modified dynamics (1993)
    [s.l.] : Nature Publishing Group
    Nature 362 (1993), S. 25-25 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Sir — Lindley's balanced comment1 on the standing of 'modified dynamics' (MOND)2 as an alternative to dark matter should bring the issue closer to the focus of attention. We would like to clarify a few points. MOND is not just a modification of the inverse distance square law of gravity. ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/362025a0
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  • 4
    Electronic Resource
    Electronic Resource
    The case against a massive black hole at the Galactic Centre (1992)
    [s.l.] : Nature Publishing Group
    Nature 359 (1992), S. 131-132 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It has been argued that the patchy and asymmetric distribution of IRS16 components with respect to SgrA* is inconsistent with the short orbit times in the near vicinity of a massive black hole4. More recent observations reveal that IRS16 consist of about 20 very luminous blue stars3 instead of 100 ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/359131a0
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  • 5
    Electronic Resource
    Electronic Resource
    Recurrent Seyfert activity in spiral galaxy nuclei (1981)
    [s.l.] : Nature Publishing Group
    Nature 294 (1981), S. 427-429 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Molecular line observations of the central region of our Galaxy have revealed some 107-108 M of interstellar gas in the inner 200 pc concentrated in massive molecular clouds (ref. 3 and refs therein). The 2.6-mm emission line of carbon monoxide has been particularly useful in mapping the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/294427a0
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  • 6
    Electronic Resource
    Electronic Resource
    Alignment of distant radio sources (1984)
    [s.l.] : Nature Publishing Group
    Nature 309 (1984), S. 35-37 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In brief, the technique used by Willson is as follows. For a pair of radio sources one first determines the angular distance, A measured along the great circle connecting the sources. If the axes of the radio sources make angles a and ? with the connecting great circle, then the angle between the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/309035a0
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  • 7
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    Hiding Lorentz invariance violation with MOND (2011)
    American Physical Society
    Details
    Publication Date: 2011-10-13
    Print ISSN: 1550-7998
    Electronic ISSN: 1550-2368
    Topics: Physics
    Published by American Physical Society
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  • 8
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    Comment on “The Bright Side of Dark Matter” (2000)
    American Physical Society
    Details
    Publication Date: 2000-08-07
    Print ISSN: 0031-9007
    Electronic ISSN: 1079-7114
    Topics: Physics
    Published by American Physical Society
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  • 9
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    A dearth of dark matter in strong gravitational lenses (2014)
    Oxford University Press
    Details
    Publication Date: 2014-03-09
    Description: I show that the lensing masses of the Sloan Lens Advanced Camera Surveys sample of strong gravitational lenses are consistent with the stellar masses determined from population synthesis models using the Salpeter initial mass function. This is true in the context of both General Relativity and modified Newtonian dynamics (MOND), and is in agreement with the expectation of MOND that there should be little classical discrepancy within the high surface brightness regions probed by strong gravitational lensing. There is also dynamical evidence from this sample supporting the claim that the mass-to-light ratio of the stellar component increases with the velocity dispersion.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 10
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    Mass discrepancies in galaxies: dark matter and alternatives (1990)
    Springer
    Details
    Publication Date: 1990-01-01
    Print ISSN: 0935-4956
    Electronic ISSN: 1432-0754
    Topics: Physics
    Published by Springer
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