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Astronomy Colloquium

Wednesday, January 25, 2012
4:00pm to 5:00pm
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Cahill, Hameetman Auditorium
Galaxies Viewed as Collections of Individual Stars
Julianne Dalcanton, University of Washington,
In extragalactic astronomy, we routinely observe galaxies in broad-band filters, and then interpret the resulting spectral energy distribution to learn about the galaxies' masses, star formation rates, ages, and metallicities. The fidelity of this interpretation relies on having a detailed understanding of the stellar populations within the galaxy, and on accurately characterizing the luminosities and colors of the billions of stars which contribute to a galaxy's light. In this talk I will discuss several large programs which use the Hubble Space Telescope to resolve millions of the most luminous stars in nearby galaxies. I will highlight results using near infrared observations, focusing on implications for the evolution of stars, the integrated NIR light of distant galaxies, and the structure of the dusty interstellar medium.
For more information, please contact Gina Armas by phone at 4671 or by email at [email protected] or visit http://www.astro.caltech.edu/~gma/colloquia.html.