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Jason Kalirai (UC Santa Cruz)
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
The NGC 6397 Group:
Rice - Jay Anderson
UBC - Harvey B. Richer, James P. Brewer, Saul D. Davis
UWashington - Ivan King
UCLA - Brad M. S. Hansen, R. Michael Rich, David B. Reitzel
Universidad de Chile - Giovanni Carraro
HIA/NRC - Gregory G. Fahlman, Peter B. Stetson
AMNH - Sebastien Lepine, Michael M. Shara
Swinburne - Jarrod R. Hurley
A FEW Reasons to Study Star Clusters:
Structure formation.
Properties of distant galaxies. Stellar evolution.
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Harris 1996, AJ, 112, 1487
Buonanno et al. 1994, A&A, 290, 69
Primary Goals:
Measure the ages of nearby globular clusters using white dwarf cooling theory.
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Dude….what the heck is a white
dwarf?
White Dwarf Cosmochronology
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Primary Goals:
Measure the ages of nearby globular clusters using white dwarf cooling theory.
1st study - Messier 4 - 123 orbits of HST/WFPC2 awarded in Cycle 11. 2nd study - NGC 6397 - 126 orbits of HST/ACS awarded in Cycle 13. 3rd study - 47 Tuc?
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Primary Goals:
Measure the ages of nearby globular clusters using white dwarf cooling theory.
1st study - Messier 4 - 123 orbits of HST/WFPC2 awarded in Cycle 11. 2nd study - NGC 6397 - 126 orbits of HST/ACS awarded in Cycle 13. 3rd study - 47 Tuc?
A clean study of the main-sequence stars: MLR, LF/MF, constrain evolutionary models.
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Proper Motions
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Kalirai et al. 2007, ApJL, 657, 93
Primary Goals:
Measure the ages of nearby globular clusters using white dwarf cooling theory.
1st study - Messier 4 - 123 orbits of HST/WFPC2 awarded in Cycle 11. 2nd study - NGC 6397 - 126 orbits of HST/ACS awarded in Cycle 13. 3rd study - 47 Tuc?
A clean study of the main-sequence stars: MLR, LF/MF, constrain evolutionary models.
Link picture from stellar evolution with dynamical evolution (internal/external).
Extra:
Globular Clusters in a Globular Cluster!
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
= +3.56 +/- 0.04 mas/yr= -17.34 +/- 0.04 mas/yr
Kalirai et al. 2007, ApJL, 657, 93
The Orbit of NGC 6397
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Richer et al. (2006, Science, 313, 936)
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Hansen et al. (2007, ApJ submitted, astro-ph/0701738)
The White Dwarf Cooling Age of NGC 6397:
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Hansen et al. (2007, ApJ submitted, astro-ph/0701738)
Age = 11.47 +/- 0.47 Gyr
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Kalirai, Strader, et al. 2007, ApJ, in prep.
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
Globular Clusters: From the Nearest to the Most Distant
Hubble Fellows Symposium - STScI
April 03, 2007
CMD of 245 globulars
NGC 6397 ---- 1Extragal. ---- 244
Summary:
White dwarf cooling age of NGC 6397 = 11.47 +/- 0.47 Gyr.
Cluster orbit suggests frequent interactions with bulge/disk.
Proper motion cleaned study of low mass cluster mass function.
z = 0.1 extragalactic globular cluster system found.
Image Credit: NASA and The Hubble Heritage Team (STScI/AURA) - Hubble Space Telescope WFPC2 - STScI-PRC03-21