1. Uncloaking globular clusters of the inner Galaxy
Javier Alonso-García
Department of Astronomy
University of Michigan
In collaboration with:
Mario Mateo (Department of Astronomy, UMich)
Bodhissatva Sen (Department of Statistics, UMich)
Moulinath Banerjee (Department of Statistics, UMich)
Michael Woodroofe (Department of Statistics, UMich)

2. Galactic spheroids contain a large fraction of the stellar mass in the local universe. (Zoccali et al. 2003, Fukugita et al. 1998)
Understanding of their formation and evolution is crucial to comprehend galaxy formation and to reconstruct the whole cosmic star formation history.

3. But it is only in a few cases that we can resolve the stellar populations.
M32
M31 bulge
MW bulge

4. The inner MW globular clusters characteristics provide powerful constraints on models of the formation and evolution of the bulge of the Milky Way.
NGC 6304
NGC 6624

5. Serious limitation in the study of many GCs: the existence of large and differential extinction by foreground dust.

6. Our Project 25 inner Galaxy GCs Imacs on Magellan
B,V and I observations
FOV 15.4’x15.4’
New dereddening technique
Goal: to determine the relative mixtures, age sequence, and chemical properties of the cluster populations in the inner Milky Way.

7. Dereddening Technique
Obtaining a ridgeline.
Moving the stars along the reddening vector.
Smoothing the shifts.
Iterative process.

8. M62
Before
After

9. M19
Before
After

10. M19

11. An important by-product of this process is a map of the differential extinction across a cluster

12. GC-Field separation
Observation
Besançon Model