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