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  • 1
    Electronic Resource
    Electronic Resource
    Dense molecular gas in galactic nuclei (1991)
    Springer
    The astronomy and astrophysics review 3 (1991), S. 47-90 
    Details
    ISSN: 1432-0754
    Keywords: Galaxies: active ; galaxies: nuclei of ; interstellar medium: molecules ; masers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The nuclear regions of many galaxies are not accessible at optical wavelengths and are devoid of HI, but contain large quantities of molecular gas and dust. With recent advances in instrumentation it is now possible to probe the kinematics and physical state of the cool dense interstellar medium, thus providing a new and important tool to investigate the circumnuclear gas in galaxies that are more ‘active’ than our own. The scope of this review is to summarize results related to the subject with an emphasis on observational data. Sects. 1 and 2 present a general introduction, followed by a discussion of molecular mass estimates. In Sect. 3 correlations between nuclear and global galactic properties are discussed. Sects. 4 and 5 summarize observational results for nearby strongly interacting galaxies, properties of molecular bars and rings, and theoretical advances in modelling the data. The main part of the review (Sects. 6–8) describes the kinematics and the physical and chemical properties of the dense gas, including masers, and compares them with the nuclear region of the Galaxy. Molecular gas in distant galaxies and the evolution of active galaxies are discussed in Sect. 9. Some promising avenues for future research are outlined in Sect. 10.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00873457
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  • 2
    Electronic Resource
    Electronic Resource
    Theory of atomic diffraction from evanescent waves (1999)
    Springer
    Applied physics 69 (1999), S. 277-289 
    Details
    ISSN: 1432-0649
    Keywords: PACS: 32.80.Lg; 42.25.Fx; 03.75.Dg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We review recent theoretical models and experiments dealing with the diffraction of neutral atoms by a reflection grating, formed by a standing evanescent wave. We analyze diffraction mechanisms proposed for normal and grazing incidence, point out their scopes and confront the theory with experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003400050808
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  • 3
    Electronic Resource
    Electronic Resource
    A geometric distance to the galaxy NGC4258 from orbital motions in a nuclear gas disk (1999)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 400 (1999), S. 539-541 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The accurate measurement of extragalactic distances is a central challenge of modern astronomy, being required for any realistic description of the age, geometry and fate of the Universe. The measurement of relative extragalactic distances has become fairly routine, but estimates of absolute ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/22972
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  • 4
    Electronic Resource
    Electronic Resource
    The OH and H"2O masers in the starbust galaxy messier 82
    Amsterdam : Elsevier
    Advances in Space Research 11 (1991), S. 369-372 
    Details
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0273-1177(91)90519-P
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  • 5
    Electronic Resource
    Electronic Resource
    Loss and heating of particles in small and noisy traps (1999)
    Springer
    Applied physics 69 (1999), S. 379-387 
    Details
    ISSN: 1432-0649
    Keywords: PACS: 03.75.-b; 32.80.Lg; 03.67.-a; 05.40.-a
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We derive the life time and loss rate for a trapped atom that is coupled to fluctuating fields in the vicinity of a room-temperature metallic and/or dielectric surface. Our results indicate a clear predominance of near-field effects over ordinary blackbody radiation. We develop a theoretical framework for both charged ions and neutral atoms with and without spin. Loss processes that are due to a transition to an untrapped internal state are included.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003400050823
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  • 6
    Electronic Resource
    Electronic Resource
    The orion-IRc2 outflow observed in COJ=4-3 (1995)
    Springer
    Astrophysics and space science 224 (1995), S. 143-149 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A CO J=4-3 map of the Orion-IRc2 region (size 80″, beam 15″) is presented. The outflow has a bipolar structure observed nearly pole-on. We interpret our observations in terms of an hierarchy of “tubes” where the fastest gas proceeds through the narrowest, innermost cone. The gas has an inhomogeneous temperature distribution and must be highly clumped. Most of the properties derived comply with the picture developed for the few known extreme high velocity outflows; however, this outflow contains exceptionally dense gas ( 〉 106 cm−3).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00667837
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  • 7
    Electronic Resource
    Electronic Resource
    Cool Dense Gas in Early-Type Galaxies (1997)
    Springer
    Space science reviews 81 (1997), S. 1-105 
    Details
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract CO observations have shown that many lenticular and elliptical galaxies contain significant amounts of cool dense gas. This review summarizes the observational results related to the neutral gas phase and presents a systematic comparison with other interstellar and stellar data. The discovery of very dense molecular gas in the nuclear regions of early-type galaxies, the possible existence of a dust component neither seen optically nor in CO, internal inconsistencies of cooling flow scenarios, the origin of the cool gas, the presence of massive stars, aspects of galaxy evolution, and possibilities for future research are discussed in the light of the new data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004979004766
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  • 8
    Electronic Resource
    Electronic Resource
    The synthesis of helium and CNO isotopes in massive stars (1995)
    Springer
    Space science reviews 74 (1995), S. 343-353 
    Details
    ISSN: 1572-9672
    Keywords: Stellar evolution ; nucleosynthesis ; mass loss ; supernovae ; chemical evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present helium and CNO isotopic yields for massive mass-losing stars in the initial mass range 15M ⊙ ≤M i ≤ 50M ⊙. We investigate their dependence on assumptions about mass loss rates, internal mixing processes, and metallicity, and specify the contributions from stellar winds and from supernova ejecta.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00751420
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  • 9
    Electronic Resource
    Electronic Resource
    Molecules in external galaxies (1989)
    Springer
    Astrophysics and space science 156 (1989), S. 263-267 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Recently, the authors reported the first detections of HNC, C2H, CN and, perhaps, HC3N toward external galaxies. These detections, as well as that of extragalactic methanol, have been obtained using the 30-m IRAM mm-wave telescope. The previous results are revised in the light of recently available high-resolution CO maps of the respective galaxies. The relative abundances are similar to those found toward warm Galactic molecular clouds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00646376
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  • 10
    Electronic Resource
    Electronic Resource
    Recoil and momentum diffusion of an atom close to a vacuum-dielectric interface (1998)
    Springer
    The European physical journal 3 (1998), S. 129-153 
    Details
    ISSN: 1434-6079
    Keywords: PACS. 32.80.Pj Optical cooling of atoms; trapping - 03.75.Be Atom and neutron optics - 42.50.Vk Mechanical effects of light on atoms, molecules, electrons, and ions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: We derive the quantum-mechanical master equation (generalized optical Bloch equation) for an atom in the vicinity of a flat dielectric surface. This equation gives access to the semiclassical radiation pressure force and the atomic momentum diffusion tensor, that are expressed in terms of the vacuum field correlation function (electromagnetic field susceptibility). It is demonstrated that the atomic center-of-mass motion provides a nonlocal probe of the electromagnetic vacuum fluctuations. We show in particular that in a circularly polarized evanescent wave, the radiation pressure force experienced by the atoms is not colinear with the evanescent wave's propagation vector. In a linearly polarized evanescent wave, the recoil per fluorescence cycle leads to a net magnetization for a J g =1/2 ground state atom.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100500050158
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