5,081 research outputs found
WISE morphological study of Wolf-Rayet nebulae
We present a morphological study of nebulae around Wolf-Rayet (WR) stars
using archival narrow-band optical and Wide-field Infrared Survey Explorer
(WISE) infrared images. The comparison among WISE images in different bands and
optical images proves to be a very efficient procedure to identify the nebular
emission from WR nebulae, and to disentangle it from that of the ISM material
along the line of sight. In particular, WR nebulae are clearly detected in the
WISE W4 band at 22 m. Analysis of available mid-IR Spitzer spectra shows
that the emission in this band is dominated by thermal emission from dust
spatially coincident with the thin nebular shell or most likely with the
leading edge of the nebula. The WR nebulae in our sample present different
morphologies that we classified into well defined WR bubbles (bubble -type nebulae), clumpy and/or disrupted shells (clumpy/disrupted -type nebulae), and material mixed with the diffuse medium (mixed -type nebulae). The variety of morphologies presented by WR nebulae shows a
loose correlation with the central star spectral type, implying that the
nebular and stellar evolutions are not simple and may proceed according to
different sequences and time-lapses. We report the discovery of an obscured
shell around WR35 only detected in the infrared.Comment: 11 pages, 6 figures, plus 23 appendix figures; to appear in Astronomy
and Astrophysic
Reseñas
Miguel MOREY, Pequeñas doctrinas de la soleda
Reduced dynamics and Lagrangian submanifolds of symplectic manifolds
In this paper, we will see that the symplectic creed by Weinstein "everything
is a Lagrangian submanifold" also holds for Hamilton-Poincar\'e and
Lagrange-Poincar\'e reduction. In fact, we show that solutions of the
Hamilton-Poincar\'e equations and of the Lagrange-Poincar\'e equations are in
one-to-one correspondence with distinguished curves in a Lagrangian submanifold
of a symplectic manifold. For this purpose, we will combine the concept of a
Tulczyjew triple with Marsden-Weinstein symplectic reduction.Comment: 26 page
Optical Absorptivity versus Molecular Composition of Model Organic Aerosol Matter
Aerosol particles affect the Earth’s energy balance by absorbing and scattering radiation according to their chemical composition, size, and shape. It is generally believed that their optical properties could be deduced from the molecular composition of the complex organic matter contained in these particles, a goal pursued by many groups via high-resolution mass spectrometry, although: (1) absorptivity is associated with structural chromophores rather than with molecular formulas, (2) compositional space is a small projection of structural space, and (3) mixtures of polar polyfunctional species usually exhibit supramolecular interactions. Here we report a suite of experiments showing that the photolysis of aqueous pyruvic acid (a proxy for aerosol α-dicarbonyls absorbing at λ > 300 nm) generates mixtures of identifiable aliphatic polyfunctional oligomers that develop absorptions in the visible upon standing in the dark. These absorptions and their induced fluorescence emissions can be repeatedly bleached and retrieved without carbon loss or ostensible changes in the electrospray mass spectra of the corresponding mixtures and display unambiguous signatures of supramolecular effects. The nonlinear additivity of the properties of the components of these mixtures supports the notion that full structural speciation is insufficient and possibly unnecessary for understanding the optical properties of aerosol particles and their responses to changing ambient conditions
Unveiling the origin of shape coexistence in lead isotopes
The shape coexistence in the nuclei Pb is analyzed within the
Hartree-Fock-Bogoliubov approach with the effective Gogny force. A good
agreement with the experimental energies is found for the coexisting spherical,
oblate and prolate states. Contrary to the established interpretation, it is
found that the low-lying prolate and oblate states observed in this mass
region are predominantly characterized by neutron correlations whereas the
protons behave as spectators rather than playing an active role.Comment: 5 pages, 6 postscript figure
La creación de productos turísticos utilizando rutas enológicas
The changes that are taking place in the tourist activity in the last years are taking to the creation of new tourist products, highlighting those related with the local and regional roots. In this paper we present an analysis on the creation and development of wine routes like tourist product in certain rural areas. And this analysis outlines it from a triple perspective: first, a study in depth they are the wine routes and its creation and development in other countries about what; second, an analysis they are certified in Spain the routes of the wine of how; and third, a reference to a route of the wine certified in Spain, that of Montilla-Moriles in the county of Córdoba
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