57,572 research outputs found

    Interplay between the ionic and electronic density profiles in liquid metal surfaces

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    First principles molecular dynamics simulations have been performed for the liquid-vapor interfaces of liquid Li, Mg, Al and Si. We analize the oscillatory ionic and valence electronic density profiles obtained, their wavelengths and the mechanisms behind their relative phase-shift.Comment: Accepted for publication in Journal of Chemical Physic

    A theory of superconductivity in multi-walled carbon nanotubes

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    We devise an approach to describe the electronic instabilities of doped multi-walled nanotubes, where each shell has in general a manifold of Fermi points. Our analysis relies on the scale dependence of the different scattering processes, showing that a pairing instability arises for a large enough number of Fermi points as a consequence of their particular geometric arrangement. The instability is enhanced by the tunneling of Cooper pairs between nearest shells, giving rise to a transition from the Luttinger liquid to a superconducting state in a wide region of the phase diagram.Comment: 4 pages, 2 figures, replaced with revised versio

    R-Band Imaging of Fields Around 1<z<2 Radiogalaxies

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    We have taken deep RR-band images of fields around five radiogalaxies: 0956+47, 1217+36, 3C256, 3C324 and 3C294 with 1<z<21<z<2 . 0956+47 is found to show a double nucleus. Our data on 1217+36 suggest the revision of its classification as a radiogalaxy. We found a statistically significant excess of bright (19.5<R<2219.5<R<22) galaxies on scales of 2 arcmin around the radiogalaxies (which have R≈21.4R \approx 21.4) in our sample. The excess has been determined empirically to be at ≳99.5%\gtrsim 99.5\% level. It is remarkable that this excess is not present for 22<R<23.7522<R<23.75 galaxies within the same area, suggesting that the excess is not physically associated to the galaxies but due to intervening groups and then related to gravitational lensing.Comment: 20 pages, uuencoded compressed PostScript including tables. Figures available upon request. To appear in the March 1995 issue of The Astronomical Journa

    XMM-Newton and Deep Optical Observations of the OTELO fields: the Groth-Westphal Strip

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    OTELO (OSIRIS Tunable Emission Line Object Survey) will be carried out with the OSIRIS instrument at the 10 m GTC telescope at La Palma, and is aimed to be the deepest and richest survey of emission line objects to date. The deep narrow-band optical data from OSIRIS will be complemented by means of additional observations that include: (i) an exploratory broad-band survey that is already being carried out in the optical domain, (ii) FIR and sub-mm observations to be carried with the Herschel space telescope and the GTM, and (iii) deep X-Ray observations from XMM-Newton and Chandra.Here we present a preliminary analysis of public EPIC data of one of the OTELO targets,the Groth-Westphal strip, gathered from the XMM-Newton Science Archive (XSA). EPIC images are combined with optical BVRI data from our broadband survey carried out with the 4.2m WHT at La Palma. Distance-independent diagnostics (involving X/O ratio, hardness ratios, B/T ratio) are tested.Comment: 2 pages, 2 figures, uses graphicx package. To appear in proceedings of "The X-Ray Universe 2005", San Lorenzo del Escorial, Spain, September 26-30, 200
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