Super-orbital variability of LS I+61 degrees 303 at TeV energies

Context. The gamma-ray binary LS I +61º303 is a well-established source from centimeter radio up to very high energy (VHE; E > 100 GeV). The broadband emission shows a periodicity of ∼26.5 days, coincident with the orbital period. A longer (super-orbital) period of 1667 ± 8 days was proposed from radio variability and confirmed using optical and high-energy (HE; E ¿ 100 MeV) gamma-ray observations. In this paper, we report on a four-year campaign performed by MAGIC together with archival data concentrating on a search for a long-timescale signature in the VHE emission from LS I +61º303. Aims. We focus on the search for super-orbital modulation of the VHE emission, similar to that observed at other energies, and on the search for correlations between TeV emission and an optical determination of the extension of the circumstellar disk. Methods. A four-year campaign has been carried out using the MAGIC telescopes. The source was observed during the orbital phases when the periodic VHE outbursts have occurred (φ = 0.55 – 0.75, one orbit = 26.496 days). Additionally, we included archival MAGIC observations and data published by the VERITAS collaboration in these studies. For the correlation studies, LS I +61◦303 has also been observed during the orbital phases where sporadic VHE emission had been detected in the past (φ = 0.75 – 1.0). These MAGIC observations were simultaneous with optical spectroscopy from the LIVERPOOL telescope. Results. The TeV flux of the periodical outburst in orbital phases φ = 0.5 – 0.75 was found to show yearly variability consistent with the long-term modulation of ∼4.5 years found in the radio band. This modulation of the TeV flux can be well described by a sine function with a best-fit period of 1610±58 days. The complete data, including archival observations, span two super-orbital periods. There is no evidence for a correlation between the TeV emission and the mass-loss rate of the Be star, but this may be affected by the strong, short-timescale (as short as intra-day) variation displayed by the Hα fluxes.

Room temperature photo-response of titanium supersaturated silicon at energies over the bandgap

Silicon samples were implanted with high Ti doses and subsequently processed with the pulsed-laser melting technique. The electronic transport properties in the 15–300 K range and the room temperature spectral photoresponse at energies over the bandgap were measured. Samples with Ti concentration below the insulator-metal (I-M) transition limit showed a progressive reduction of the carrier lifetime in the implanted layer as Ti dose is increased. However, when the Ti concentration exceeded this limit, an extraordinary recovery of the photoresponse was measured. This result supports the theory of intermediate band materials and is of utmost relevance for photovoltaic cells and Si-based detectors.

Poética homo: propuesta metodológica para el análisis de la sexo-diversidad, con un enfoque en el género masculino, en el teatro. Teatro mexicano s. XX

El trabajo que aquí se presenta surge de una doble inquietud. Por una parte establecer el análisis de las obras de teatro, a partir de entender estas como un producto artístico en cuanto a material literario y hecho escénico se refiere, y por otra la necesidad, no de definir la homosexualidad, sino el entender cuáles han sido los recursos dramáticos a través de los que se ha manifestado la tematización de la diversidad sexual masculina, y cómo han sido empleados en el fenómeno teatral. Los trabajos de investigación y crítica que han sido elaborados sobre el tema homosexual se han llevado a cabo, principalmente, en disciplinas como la psicología y la antropología. En el ámbito de las letras dichos estudios se han centrado tan solo en dos de los géneros literarios: la poesía y la narrativa; haciendo a un lado al otro gran género que es el teatro. Son pocos los estudios que se han realizado en torno al teatro homosexual, por tanto el tesista se atreve a afirmar que dicho terreno de investigación se encuentra despoblado. Para entender la homosexualidad dentro del teatro, es necesario acercarnos a la historia natural de la misma, es decir al recorrido sintagmático que ha presentado en la historia del hombre, de manera que se puedan comprender y comparar así las manifestaciones paradigmáticas que han surgido en la historia del teatro...