4,310 research outputs found

    Infrared excesses in stars with and without planets using revised WISE{\it WISE} photometry

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    We present an analysis on the potential prevalence of mid infrared excesses in stars with and without planetary companions. Based on an extended database of stars detected with the WISE{\it WISE} satellite, we studied two stellar samples: one with 236 planet hosts and another with 986 objects for which planets have been searched but not found. We determined the presence of an excess over the photosphere by comparing the observed flux ratio at 22 μ\mum and 12 μ\mum (f22/f12f_{22}/f_{12}) with the corresponding synthetic value, derived from results of classical model photospheres. We found a detection rate of 0.85%\% at 22 μ\mum (2 excesses) in the sample of stars with planets and 0.1%\% (1 detection) for the stars without planets. The difference of the detection rate between the two samples is not statistically significant, a result that is independent of the different approaches found in the literature to define an excess in the wavelength range covered by WISE{\it WISE} observations. As an additional result, we found that the WISE{\it WISE} fluxes required a normalisation procedure to make them compatible with synthetic data, probably pointing out a revision of the WISE{\it WISE} data calibration.Comment: 10 pages, 6 figures, 3 tables. Accepted for publication in MNRA

    Theoretical description of two ultracold atoms in finite 3D optical lattices using realistic interatomic interaction potentials

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    A theoretical approach is described for an exact numerical treatment of a pair of ultracold atoms interacting via a central potential that are trapped in a finite three-dimensional optical lattice. The coupling of center-of-mass and relative-motion coordinates is treated using an exact diagonalization (configuration-interaction) approach. The orthorhombic symmetry of an optical lattice with three different but orthogonal lattice vectors is explicitly considered as is the Fermionic or Bosonic symmetry in the case of indistinguishable particles.Comment: 19 pages, 5 figure

    Site and lattice resonances in metallic hole arrays

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    A powerful analytical approach is followed to study light transmission through subwavelength holes drilled in thick perfect-conductor films, showing that full transmission (100%) is attainable in arrays of arbitrarily narrow holes as compared to the film thickness. The interplay between resonances localized in individual holes and lattice resonances originating in the array periodicity reveals new mechanisms of transmission enhancement and suppression. In particular, localized resonances obtained by filling the holes with high-index-of-refraction material are examined and experimentally observed through large enhancement in the transmission of individual holes.Comment: 5 figure

    ¡Tigre Blanco, héroe del Barrio!: Living and Dying Latina/o in a Superhero World

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    ¡Tigre Blanco, héroe del Barrio!: Living and Dying Latina/o in a Superhero World

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