47 research outputs found
Evolution of the Small Magellanic Cloud
Based on the results of N-body simulations on the last 2.5 Gyr evolution of
the Large and Small Magellanic Clouds (LMC and SMC, respectively) interacting
with the Galaxy, we firstly show when and where the leading arms (LAs) of the
Magellanic stream (MS) can pass through the Galactic plane after the MS
formation. We secondly show collisions between the outer Galactic HI disk and
the LAs of the MS can create giant HI holes and chimney-like structures in the
disk about 0.2 Gyr ago. We thirdly show that a large amount of metal-poor gas
is stripped from the SMC and transfered to the LMC during the tidal interaction
between the Clouds and the Galaxy about 0.2 and 1.3 Gyr ago. We thus propose
that this metal-poor gas can closely be associated with the origin of LMC's
young and intermediate-age stars and star clusters with distinctively
low-metallicities with [Fe/H] < -0.6.Comment: 4 pages, 3 figures, to appear in the proceedings of ``Galaxies in the
Local Volume'', Sydney, 8 to 13 July, 200
Fast Integrated Spectra Analyzer: A New Computational Tool For Age and Reddening Determination of Small Angular Diameter Open Clusters
We present a new algorithm called 'Fast Integrated Spectra Analyzer" (FISA)
that permits fast and reasonably accurate age and reddening determinations for
small angular diameter open clusters by using their integrated spectra in the
(3600-7400) \AA \ range and currently available template spectrum libraries.
This algorithm and its implementation help to achieve astrophysical results in
shorter times than from other methods. A brief review is given of the
integrated spectroscopic technique applied to the study of open clusters as
well as the basic assumptions that justify its use. We describe the numerical
algorithm employed in detail, show examples of its application, and provide a
link to the code. Our method has successfully been applied to integrated
spectroscopy of open clusters, both in the Galaxy and in the Magellanic Clouds,
to determine ages and reddenings.Comment: 27 Pages, 7 Figures, 1 table. Accepted to PAS
Áreas Potenciais à Formação De Corredores Ecológicos Entre Remanescentes De Mata Atlântica
In Brazil, the remaining areas of Atlantic Forest are intensely fragmented. The connection of forest fragments through ecological corridors is an important step in biodiversity conservation. Certain areas are more resilient, and in those areas, natural forest regeneration, for example, can be encouraged. The aim of this study was to identify areas of greater resilience in order to support the connection of Atlantic Forest fragments with ecological corridors. Forest fragments in the municipality of Paraíba do Sul, in the state of Rio de Janeiro, were mapped using the supervised maximum likelihood classification of an Operational Land Imager (OLI)/Landsat-8 sensor image. Next, we analyzed the influence of terrain attributes (aspect, incident solar radiation, slope, and curvature profile) on natural regeneration. The areas with the greatest potential to achieve natural regeneration and to form ecological corridors were indicated through fuzzy membership functions. Within Paraíba do Sul, 31% of the territory is covered by vegetation in different stages of regeneration. Recordings were made of 1,251 forest fragments in a middle or advanced stage of regeneration. These fragments are usually situated in the southeast, south, and southwest aspects, in areas that receive the least amount of global solar radiation (Wh·m-2) per year, and on slopes with an angle of inclination greater than 20%. The adjustment of fuzzy functions identified 17,327.5 ha with a tendency to recover, and which are therefore strategic areas in the development of ecological corridors. © 2016, Sociedade de Investigacoes Florestais. All rights reserved.40580381