Optical polarimetric monitoring of the type II-plateau SN 2005af

Aims. Core-collapse supernovae may show significant polarization that implies non-spherically symmetric explosions. We observed the type II-plateau SN 2005af using optical polarimetry in order to verify whether any asphericity is present in the supernova temporal evolution. Methods. We used the IAGPOL imaging polarimeter to obtain optical linear polarization measurements in R (five epochs) and V (one epoch) broadbands. Interstellar polarization was estimated from the field stars in the CCD frames. The optical polarimetric monitoring began around one month after the explosion and lasted ~30 days, between the plateau and the early nebular phase. Results. The weighted mean observed polarization in R band was [1.89 +/- 0.03]% at position angle (PA) 54 deg. After foreground subtraction, the level of the average intrinsic polarization for SN 2005af was ~0.5% with a slight enhancement during the plateau phase and a decline at early nebular phase. A rotation in PA on a time scale of days was also observed. The polarimetric evolution of SN 2005af in the observed epochs is consistent with an overall asphericity of ~20% and an inclination of ~30 deg. Evidence for a more complex, evolving asphericity, possibly involving clumps in the SN 2005af envelope, is found.Comment: 6 pages, 5 figures, to be published A&

Al compás de las imágenes, del fotograma a la web

En sus más de dos décadas de existencia, el Centro de Documentación Histórica del ISEF N° 1, “Dra. Gilda Lamarque de Romero Brest” llevó a cabo una significativa tarea de difusión de su patrimonio, que atendió a la vez a su preservación. Entre la documentación que originalmente lo conformó se destaca la colección de libros de calificaciones del Instituto, que aunque incompleta se remonta al momento de su creación: el año 1906. En el conjunto de materiales históricos que hoy atesora el Centro de Documentación Histórica, consistente en libros, revistas, folletos, documentos, objetos, material iconográfico y fotografías, las últimas se destacan por su número, que las hace cuantitativamente relevantes, pero sobre todo por su calidad técnica y por la diversidad de temáticas que retratan. La colección representa un cuantioso e importante acervo iconográfico enfocado en la documentación de docentes y alumnos del instituto, que se remonta a los comienzos del siglo XX y los retrata, en la mayoría de los casos, en forma grupal. (Párrafo extraído del texto a modo de resumen)Eje 6: Las prácticas de la Educación Física y la construcción de relatos: historia, memoria y comunicación. Mesa de Trabajo C: Historia de la educación física.Departamento de Educación Físic

Further Criteria for the Existence of Steady Line-Driven Winds

In Paper I, we showed that steady line-driven disk wind solutions can exist by using "simple" models that mimic the disk environment. Here I extend the concepts introduced in Paper I and discuss many details of the analysis of the steady/unsteady nature of 1D line-driven winds. This work confirms the results and conclusions of Paper I, and is thus consistent with the steady nature of the 1D streamline line-driven disk wind models of Murray and collaborators and the 2.5D line-driven disk wind models of Pereyra and collaborators. When including gas pressures effects, as is routinely done in time-dependent numerical models, I find that the spatial dependence of the nozzle function continues to play a key role in determining the steady/unsteady nature of supersonic line-driven wind solutions. I show here that the existence/nonexistence of local wind solutions can be proved through the nozzle function without integrating the equation of motion. This work sets a detailed framework with which we will analyze, in a following paper, more realistic models than the "simple" models of Paper I.Comment: 30 pages, 5 figures, accepted for publication by The Astrophysical Journa