Extensive near-infrared (H-band) photometry in Coma

We present extensive and accurate photometry in the near-infrared H band of a complete sample of objects in an area of about 400 arcmin2 toward the Coma cluster of galaxies. The sample, including about 300 objects, is complete down to H~17 mag, the exact value depending on the type of magnitude (isophotal, aperture, Kron) and the particular region studied. This is six magnitudes below the characteristic magnitude of galaxies, well into the dwarfs' regime at the distance of the Coma cluster. For each object (star or galaxy) we provide aperture magnitudes computed within five different apertures, the magnitude within the 22 mag arcsec2 isophote, the Kron magnitude and radius, magnitude errors, as well as the coordinates, the isophotal area, and a stellarity index. Photometric errors are 0.2 mag at the completness limit. This sample is meant to be the zero-redshift reference for evolutionary studies of galaxies.Comment: A&AS in press, paper, with high resolution images & tables are available at http://oacosf.na.astro.it/~andreon/listapub.htm

Extragalactic Background Light and Gamma-Ray Attenuation

Data from (non-) attenuation of gamma rays from active galactic nuclei (AGN) and gamma ray bursts (GRBs) give upper limits on the extragalactic background light (EBL) from the UV to the mid-IR that are only a little above the lower limits from observed galaxies. These upper limits now rule out some EBL models and purported observations, with improved data likely to provide even stronger constraints. We present EBL calculations both based on multiwavelength observations of thousands of galaxies and also based on semi-analytic models, and show that they are consistent with these lower limits from observed galaxies and with the gamma-ray upper limit constraints. Such comparisons "close the loop" on cosmological galaxy formation models, since they account for all the light, including that from galaxies too faint to see. We compare our results with those of other recent works, and discuss the implications of these new EBL calculations for gamma ray attenuation. Catching a few GRBs with groundbased atmospheric Cherenkov Telescope (ACT) arrays or water Cherenkov detectors could provide important new constraints on the high-redshift star formation history of the universe.Comment: 12 pages, 8 multi-panel figures, Invited talk at the 25th Texas Symposium on Relativistic Astrophysics, Heidelberg December 6-10, 201

Granular-Scale Elementary Flux Emergence Episodes in a Solar Active Region

We analyze data from Hinode spacecraft taken over two 54-minute periods during the emergence of AR 11024. We focus on small-scale portions within the observed solar active region and discover the appearance of very distinctive small-scale and short-lived dark features in Ca II H chromospheric filtergrams and Stokes I images. The features appear in regions with close-to-zero longitudinal magnetic field, and are observed to increase in length before they eventually disappear. Energy release in the low chromospheric line is detected while the dark features are fading. In time series of magnetograms a diverging bipolar configuration is observed accompanying the appearance of the dark features and the brightenings. The observed phenomena are explained as evidencing elementary flux emergence in the solar atmosphere, i.e small-scale arch filament systems rising up from the photosphere to the lower chromosphere with a length scale of a few solar granules. Brightenings are explained as being the signatures of chromospheric heating triggered by reconnection of the rising loops (once they reached chromospheric heights) with pre-existing magnetic fields as well as to reconnection/cancellation events in U-loop segments of emerging serpentine fields. We study the temporal evolution and dynamics of the events and compare them with the emergence of magnetic loops detected in quiet sun regions and serpentine flux emergence signatures in active regions. Incorporating the novel features of granular-scale flux emergence presented in this study we advance the scenario for serpentine flux emergence.Comment: 24 pages, 9 figures. Accepted for publication in Solar Physic

On p_T-broadening of high energy partons associated with the LPM effect in a finite-volume QCD medium

We study the contributions from radiation to $p_{\perp}$-broadening of a high energy parton traversing a QCD medium with a finite length $L$. The interaction between the parton and the medium is described by decorrelated static multiple scattering. Amplitudes of medium-induced gluon emission and parton self-energy diagrams are evaluated in the soft gluon limit in the BDMPS formalism. We find both the double-logarithmic correction from incoherent scattering, which is parametrically the same as that in single scattering, and the logarithmic correction from the LPM effect. Therefore, we expect a parametrically large correction from radiation to the medium-induced $p_\perp$-broadening in perturbative QCD.Comment: 19 pages, focusing only on calculations about the medium-induced diagrams, origin for double-log reinterpreted, final version to appear in JHE

Aplicación del modelo modergis en el uso sostenible en la dendroenergía y los biocombustibles para países en vía de desarrollo- caso Colombia.

Numerosos países en vía de desarrollo caso Colombia, contienen un enorme potencial de recursos en energías renovables como la dendroenergía incluidos los biocombustibles, pero no se utilizan en gran magnitud ni se han incorporado al Mix Energético Nacional debido a la falta de herramientas que las evalué e integre de manera armónico y con criterio sostenible. En tal sentido la Universidad Nacional de Colombia y el Centro de Investigaciones Energéticas Medioambientales y Tecnológicas - CIEMAT de España, han desarrollado conjuntamente una herramienta de planificación energética sostenible denominada - MODERGIS - que tiene como objeto la incorporación, evaluación y análisis de energías renovables con énfasis a la dendroenergía y los biocombustibles utilizando las técnicas de los Sistemas de Información Geográfica - SIG, como instrumento alternativo de planificación y uso sostenible ambiental, social, económico y cultural del uso del suelo. El modelo esta conformado por tres componentes: ENERDEM modelo de demanda- oferta de energía, ENERSIG: espacialización e integración de energías renovables mediante los Sistemas de Información Geográfica - SIG y ENERSOS modelo basado en métodos de análisis multiobjetivo tendientes a optimizar las dimensiones de la sostenibilidad de las fuentes energética, incorporando el análisis de ciclo de vida. Los resultados preliminares del modelo presentan 6.8 Millones de hectáreas factibles en el uso de la Dendroenergía, el cual significaría un potencial de 4400 MW instalables si se dedicara en la producción de energía eléctrica. En biocombustibles el Biodiesel de palma de aceite arroja un potencial de 1017 millones de barriles y 54 millones de barriles de etanol de caña de azúcar, el cual justificaría proporciones de abastecimiento interno con las mezclas de E10 y B5, quedando un gran potencial para interferir el mercado internacional, lo cual con la metodología de ModerGIS tiene incluido los criterios de sostenibilidad que son necesarios para ingresar a estos mercados.An essential element to reach sustainable development is an appropriate and reliable energy supply. This helps to eradicate poverty, improve human welfare, and to raise quality of life in the population. However, many regions in the world do not have a reliable supply, and its use exceeds economic limits, creating a dichotomy between growth and sustainability. World institutons such as United Nations and its organization UNESCO, have demonstrated that current energy production and consumption models are not sustainable in a medium term. Many countries, especially those that are in development such as Colombia, have a great potential of renewable energy resources that have not been used or incorporated into the energy mix due to the lack of tools to evaluate and to integrate them with a sustainability criteria. Then, “Universidad Nacional de Colombia” (Colombia) and “Centro de Investigaciones Energéticas Medioambientales y Tecnológicas – CIEMAT” (Spain) have jointly developed an integrated energy planning tool named MODERGIS. Its objective is to incorporate, evaluate and analyze renewable resources such as wood energy including biofuels. This model comprises three constitutive elements: an energy supply-demand model (ENERDEM), an integration and space definition of renewable energy through geographic information systems (ENERSIG), and a multi-objectiveanalysis to optimize sustainability dimensions of energy sources (ENERSOS). The current paper shows some of the preliminary results of this model, and discusses on the methodological issues faced during its development. Further and more expanded results are expected to be published in the near future

Photonic realization of the relativistic Kronig-Penney model and relativistic Tamm surface states

Photonic analogues of the relativistic Kronig-Penney model and of relativistic surface Tamm states are proposed for light propagation in fibre Bragg gratings (FBGs) with phase defects. A periodic sequence of phase slips in the FBG realizes the relativistic Kronig-Penney model, the band structure of which being mapped into the spectral response of the FBG. For the semi-infinite FBG Tamm surface states can appear and can be visualized as narrow resonance peaks in the transmission spectrum of the grating

Pluri-Canonical Models of Supersymmetric Curves

This paper is about pluri-canonical models of supersymmetric (susy) curves. Susy curves are generalisations of Riemann surfaces in the realm of super geometry. Their moduli space is a key object in supersymmetric string theory. We study the pluri-canonical models of a susy curve, and we make some considerations about Hilbert schemes and moduli spaces of susy curves.Comment: To appear in the proceedings of the intensive period "Perspectives in Lie Algebras", held at the CRM Ennio De Giorgi, Pisa, Italy, 201