jueves, 22 de marzo de 2012

Programa de profesores visitantes OAC/UNC

A partir de 2011, el Observatorio Astronómico, en el ámbito de la Universidad, implementa el Programa de profesores visitantes.

Este programa consiste de una serie de visitas de reconocidos profesores, quienes dictarán cursos breves de su especialidad y participarán de talleres para la interacción con alumnos e investigadores.

Ciclo 2012

Profesora Katherine Vieira Tema de las charlas: "PROGRAMA DE MOVIMIENTOS PROPIOS DEL SUR" Fecha de las charlas: Lunes 26/03 y Martes 27/03 a las 11 hs.

Lunes 26/03, 11 hs


The Southern Proper Motion Program. IV. The SPM4 Catalog 
We present the fourth installment of the Yale/San Juan Southern Proper Motion Catalog, SPM4. The SPM4 contains absolute proper motions, celestial coordinates, and B, V photometry for over 103 million stars and galaxies between the south celestial pole and -20° declination. The catalog is roughly complete to V = 17.5 and is based on photographic and CCD observations taken with the Yale Southern Observatory's double astrograph at Cesco Observatory in El Leoncito, Argentina. The proper-motion precision, for well-measured stars, is estimated to be 2-3 mas yr-1, depending on the type of second-epoch material. At the bright end, proper motions are on the International Celestial Reference System by way of Hipparcos Catalog stars, while the faint end is anchored to the inertial system using external galaxies. Systematic uncertainties in the absolute proper motions are on the order of 1 mas yr-1.

Martes 27/03, 11 hs


Constraints on the Magellanic Clouds' Interaction from the Distribution of OB Stars and the Kinematics of Giants 
Young, OB-type candidates are identified in a 7900 deg2 region encompassing the Large and Small Magellanic Clouds (LMC/SMC), the Bridge, part of the Magellanic Stream (MS) and Leading Arm (LA). Selection is based on UV, optical and IR photometry from existing large-area surveys and proper motions from the Southern Proper Motion 4 catalog (SPM4). The spatial distribution of these young star candidates shows 1) a well-populated SMC wing which continues westward with two branches partially surrounding the SMC, 2) a rather narrow path from the SMC wing eastward toward the LMC which is offset by 1 - 2 from the high-density H I ridge in the Bridge, 3) a well-populated periphery of the LMC including clumps of stars at the ends of the LMC bar and 4) a few scattered candidates in the MS and two overdensities in the LA regions above and below the Galactic plane. Additionally, a proper-motion analysis is made of a radial-velocity selected sample of red giants and supergiants in the LMC, shown by Olsen et al. (2011) to be a kinematically and chemically distinct subgroup, most likely captured from the SMC. SPM4 proper motions of these stars also indicate they are distinct from the LMC population. Of the two possible kinematical descriptions proposed by Olsen et al. for the captured SMC stars, the proper motions favor their being in a prograde rotation at an angle of 54 with respect to the LMC's disk. The observational results presented here, together with the known orbits of the Clouds, as well as other aspects of the LMC morphology, point to an offcenter, moderate to highly-inclined collision between the SMC and the LMC's disk that took place between 100 and 200 Myr ago.

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