# I Milky Way's Globular Clusters

1. Jan 23, 2017

### Jamison Lahman

My question is directly towards figure 2.15 from Galaxies in the Universe, An Introduction by Sparke and Gallagher.

Everything in the figure makes sense to me until the authors make the point, "Clusters with a blue horizontal branch (filled dots) are more concentrated to the center than are those with a red horizontal branch (open circles)."

My understanding is that metal-rich clusters will have a redder horizontal branch and metal-rich clusters are concentrated near the galactic center as shown by the left side. Why then, are the bluer horizontal branches concentrated towards the center?

Thanks,
Jamison

2. Feb 12, 2017