Special Seminars: 2011
|Origins of Stars and Planets: 2020 Vision(s)|
Institute for Astronomy, ETH, Zurich
|Characterizing Magnetized Turbulence in Molecular Clouds and Galaxies|
University of Western Ontario
|Universe or Multiverse|
|The GMT Integral-Field Spectrograph (GMTIFS): What It Can Do for You!|
Australian National University
|Accretion, jets and winds: High-energy emission from young stellar objects|
Harvard-Smithsonian Center for Astrophysics
- January 2011
January 3, 2011 | 13:30, LASR-E Conference Room | Host: Arieh Konigl
Origins of Stars and Planets: 2020 Vision(s)
Michael Meyer, Institute for Astronomy, ETH, Zurich
Despite recent setbacks, the next decade should still see the realization of two revolutionary capabilities in astrophysics: the launch of the James Webb Space Telescope and (hopefully) first light for at least one Extremely Large Telescope (such as the GMT or the E-ELT). Both of these will make fundamental contributions towards understanding the origins of stars (like our Sun) and planetary systems (like our own), and thus our place in the Universe. I will compare and contrast these facilities from the perspective of star and planet formation, with a focus on the direct detection of extra-solar planets as a critical test for theories of planet formation and evolution (based on extrapolation from current work).
- February 2011
February 25, 2011 | 15:00, RI 180 | Host: Roger H. Hildebrand
Characterizing Magnetized Turbulence in Molecular Clouds and Galaxies
Martin Houde, University of Western Ontario
While Submillimetre polarimetry of dust emission is arguably the most common observational tool to probe magnetic fields in molecular clouds, it has mainly been used to provide a measure of their geometry and their strength through the so-called Chandrasekhar-Fermi technique. The usefulness and accuracy of this technique are however hampered by observational biases, such as the signal integration along the line of sight and across the telescope beam. I will show how it is possible to account and correct for this effect, and significantly improve results obtained with the Chandrasekhar-Fermi equation. I will also discuss how an extension of this analysis can lead to a complete characterization of the magnetized turbulence power spectrum in molecular clouds and Galaxies (using polarization of synchrotron emission). I will present examples showing measurements of the turbulent energy dissipation scale due to ambipolar diffusion,and of the anisotropy of the magnetized turbulent power spectrum
- April 2011
- September 2011
September 20, 2011 | 10:00, AAC 123 | Host: Richard G. Kron
The GMT Integral-Field Spectrograph (GMTIFS): What It Can Do for You!
Peter McGregor, Australian National University
The GMT Integral-Field Spectrograph (GMTIFS) is one of six potential first-light instruments for the 25m-diameter Giant Magellan Telescope. The Australian National University has completed a Conceptual Design Study for GMTIFS. I will summarize the sciences cases for GMTIFS, and describe the instrument capabilities and design. GMTIFS will be the work-horse adaptive-optics instrument on GMT. It will address a wide range of science from epoch of reionization studies to forming galaxies at high redshifts, to star and planet formation in our Galaxy, and studies of the Solar system. These are largely the science case for Laser-Tomography Adaptive Optics on the telescope. I will describe why you will want to routinely use LTAO with GMTIFS for your science in the 2020s.
- October 2011
October 10, 2011 | 15:00, AAC 123 | Host: Arieh Konigl
Accretion, jets and winds: High-energy emission from young stellar objects
Hans Moritz Guenther, Harvard-Smithsonian Center for Astrophysics
Young stars form by contraction from large molecular clouds, they accrete mass from their environment. In the stage of classical T Tauri stars (CTTS) they are surrounded by an accretion disk, in which planet formation takes place. At this time, there are three possible mechanisms to power X-ray and UV emission: First, a corona similar to main-sequence stars, second, an accretion shock when infalling matter from the disk hits the star and, third, wind and collimated jets.
I will present X-ray and UV observations that tell us about the physical conditions in the emission regions and show that all three mechanisms can be observed, albeit to a different degree in different objects.