Abstract by Christa Gall
Dust plays an essential role in the formation of stars and evolution of galaxies. Large amounts of dust detected in sub-millimeter galaxies and quasars at high redshift, bear witness of a rapid production of dust. Massive stars ending their lives as either asymptotic giant branch stars or supernovae have been contemplated as the prime sources of dust, but it is uncertain whether their dust production efficiency is sufficient to account for the large dust masses observed. I shall address the challenge of determining dust masses observationally and discuss the contribution of stellar dust sources to the dust budget in the high redshift universe as well as in Local Group galaxies.
Friday, November 30, 2012
Thursday, November 29, 2012
Friday Nov. 30th at 12pm: Joint meeting with the galaxy club
Life Cycles of Star Clusters
Michael Fall (STScI)
This talk presents an overview of the life cycles of star clusters from their their birth in dense molecular clouds to their eventual dissolution in the diffuse stellar field. The talk summarizes several of our recent observational and theoretical studies. One of our main findings is a remarkable similarity in the populations of clusters in different galaxies (giant and dwarf, interacting and quiescent). We discuss the most likely physical reasons for this similarity. The resulting picture helps to unify a mostly descriptive subject with a complicated nomenclature (including associations and open, populous, super, and globular clusters).
The structural evolution of galaxies from z=2.5 to z=0
Daniel Szomoru (Leiden)
Massive galaxies have undergone tremendous changes in their structure and morphology since z=2.5. Although observational and theoretical uncertainties remain significant, a coherent picture of the evolution of massive galaxies over the past 11 Gyr is starting to emerge. I will discuss recent results, focusing on the structure of high-redshift quiescent galaxies, their rapid evolution, and the implications of these results on our knowledge of galaxy evolution.
Michael Fall (STScI)
This talk presents an overview of the life cycles of star clusters from their their birth in dense molecular clouds to their eventual dissolution in the diffuse stellar field. The talk summarizes several of our recent observational and theoretical studies. One of our main findings is a remarkable similarity in the populations of clusters in different galaxies (giant and dwarf, interacting and quiescent). We discuss the most likely physical reasons for this similarity. The resulting picture helps to unify a mostly descriptive subject with a complicated nomenclature (including associations and open, populous, super, and globular clusters).
The structural evolution of galaxies from z=2.5 to z=0
Daniel Szomoru (Leiden)
Massive galaxies have undergone tremendous changes in their structure and morphology since z=2.5. Although observational and theoretical uncertainties remain significant, a coherent picture of the evolution of massive galaxies over the past 11 Gyr is starting to emerge. I will discuss recent results, focusing on the structure of high-redshift quiescent galaxies, their rapid evolution, and the implications of these results on our knowledge of galaxy evolution.
Thursday, November 8, 2012
Thursday November 15th: New ideas in stellar magnetism, and the magnetorotational instability
Abstract by Geoff Vasil
Understanding the mechanisms behind solar magnetism remains one of the longest-standing unsolved problems in physics. Despite an impressive amount of observations, from early counts of sunspots to the recent data coming from the Solar Dynamics Observatory and the Kepler mission, no one understands how the sun's global magnetic dynamo machine operates. Over the last few decades theories have risen and fallen and radically new ideas are needed to make progress. In this talk, I will present a new model of the dynamics of the sun's layers. It is based on the magneto-rotational instability (MRI) and is equivalent to the dynamics of a buckling elastic beam under an applied load. While still only a qualitative model, it can possibly explain the migration of the equator branch of the solar torsional oscillation pattern, which correlates highly with sunspot migration, a phenomenon that has strongly resisted explanation to date.
Understanding the mechanisms behind solar magnetism remains one of the longest-standing unsolved problems in physics. Despite an impressive amount of observations, from early counts of sunspots to the recent data coming from the Solar Dynamics Observatory and the Kepler mission, no one understands how the sun's global magnetic dynamo machine operates. Over the last few decades theories have risen and fallen and radically new ideas are needed to make progress. In this talk, I will present a new model of the dynamics of the sun's layers. It is based on the magneto-rotational instability (MRI) and is equivalent to the dynamics of a buckling elastic beam under an applied load. While still only a qualitative model, it can possibly explain the migration of the equator branch of the solar torsional oscillation pattern, which correlates highly with sunspot migration, a phenomenon that has strongly resisted explanation to date.
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