Abstract by Fabio Antonini
My talk will focus on the origin of the S-stars, the young stars near the supermassive black hole (SMBH) at the Galactic center. We apply recent insights about how relativity interacts with Newtonian (star-star) perturbations near Schwarzschild and Kerr SBHs to the S-stars and put constraints on competing models for their origin and stellar cusp parameters.
For the first time we show that the orbital distribution of the S-stars predicted by formation scenarios which
invoke the tidal disruption of binary stars by the SBH are consistent with observations. However, I will also show that the S-star orbits can only be reproduced by assuming dynamically relaxed models (i.e., steep density cusps) for the Galactic center. I will conclude by discussing the importance of resonant relaxation in terms of tidal disruption events in galactic nuclei.
Tuesday, April 23, 2013
Monday, April 1, 2013
Friday, April 5: "Embedded Clusters as Laboratories of Star Formation"
Abstract by Arjan Bik
Massive stars are typically observed to form in clustered environments, with morphologies ranging from very dense, centrally concentrated starburst clusters to loose associations. These associations and clusters are morphologically and dynamically different. It is not clear if these differences arise from different initial conditions in the star formation process or environmental effects, like triggered star formation. We have started a large observational campaign to derive the star formation history of several massive star formation complexes in order to reconstruct the star formation mechanisms. I will demonstrate that near-infrared spectroscopy and photometry using LBT and VLT, combined with a large suite of multi-wavelength observations allow us to obtain a detailed picture of the stellar clusters and their stellar populations. Different stellar populations are found in many embedded clusters, suggesting that the star formation history is much more complex than a single star formation event. Based on LBT multi-object spectroscopy of the massive stellar content of W3 Main I will present evidence for an age spread where the oldest massive star formed 2-3 Myrs ago while some other massive stars are still in their formation process.
Massive stars are typically observed to form in clustered environments, with morphologies ranging from very dense, centrally concentrated starburst clusters to loose associations. These associations and clusters are morphologically and dynamically different. It is not clear if these differences arise from different initial conditions in the star formation process or environmental effects, like triggered star formation. We have started a large observational campaign to derive the star formation history of several massive star formation complexes in order to reconstruct the star formation mechanisms. I will demonstrate that near-infrared spectroscopy and photometry using LBT and VLT, combined with a large suite of multi-wavelength observations allow us to obtain a detailed picture of the stellar clusters and their stellar populations. Different stellar populations are found in many embedded clusters, suggesting that the star formation history is much more complex than a single star formation event. Based on LBT multi-object spectroscopy of the massive stellar content of W3 Main I will present evidence for an age spread where the oldest massive star formed 2-3 Myrs ago while some other massive stars are still in their formation process.
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