Found 14 talks width keyword stellar content

Thursday October 18, 2012


The basis of stellar population modeling was established around 40 years ago somehow
optimized to the technical facilities and observational data available at that epoch. Since then,
it has been used extensively in astronomy and there has been great improvements relating
their associated ingredients in concordance with the development of more powerful computational
and observational facilities.
However, there has been no similar improvements in the understanding about what is
actually modeling neither in improve the modeling itself to include the current technical advances
to obtain more accurate result in the physical inferences obtained from them.
In this talk I present some advances in the subject of stellar
population modeling and how to take advantage of current facilities to obtain more robust
and accurate inferences from stellar systems at different scales
covering the continuum between fully resolved populations to fully unresolved ones in a unified framework.

Tuesday September 27, 2011
Instituto de Astrofísica de Canarias, Spain


In the last few years there has been cumulative evidence showing that massive galaxies have dramatically grown in size since z~3. This result has remained very controversial as it seems at odd with our previous knowledge based on the detailed analysis of the stellar populations of nearby massive spheroids which shows that their stars were form very early on and over a short time interval. In addition to this, there is growing observational support for a significant evolution of the morphologies of these galaxies with cosmic time. In this talk, I will summarize what we have learned since the discovery of the strong evolution of the morphological properties of the massive galaxies, the mechanisms proposed to explain their origin and size increase, and the pending questions still to solve.

Friday June 17, 2011
University of Padova, Italy


We present the K band FP of the ETGs members of the clusters observed by the WINGS survey. The data confirm a different tilt of the FP with respect to the V solution and the presence of a substantial tilt in the K band. This led us to further investigate the hypothesis that ETG non-homology greatly contribute to the tilt of the FP.

The WINGS data show that there are now several evidence of both structural and dynamical non-homology for the class of ETGs. Among these we will discuss in detail the tight relation between the mass of the ETGs, their stellar mass-to-light ratio M/L, and the Sersic index n describing the shape of their light profiles. We guess through a series of mock simulations that this relation acts as a fine-tuning that keeps small the scatter around the FP. We therefore conclude that ETG non-homology is closely connected either with the problem of the tilt and with the small scatter around the FP.

Tuesday June 7, 2011
MPIA, Germany


With imaging at 3.6 and 4.5 microns where the light in nearby galaxies is dominated by old stars, the Spitzer Survey of Nearby Galaxies (S4G) stands poised for an optimal view of stellar mass and structure in the local Universe.  I will describe an effort to construct accurate 2D stellar mass maps from S4G images, starting with a correction for non-stellar (e.g. PAH and hot dust) contaminant emission using only the two S4G images as inputs; contaminant emission is isolated from the old stellar light using an Independent Component Analysis (ICA) technique designed to separate statistically independent source distributions.  An inventory of recovered contaminants is established via comparison to the non-stellar emission in archival 8 micron images.  Once these contaminants are removed, maps of the underlying distribution of old stars are revealed that retain a high degree of structural information and exhibit [3.6]-[4.5] colors consistent with those of K and M giants.  Contaminant-free S4G maps constructed with this approach should be ideally suited for tracing the stellar mass in galaxies spanning a range of morphological properties, dust contents and star formation histories.

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