Uncloaking globular clusters in the inner Galaxy

TL;DR

This paper provides a homogeneous photometric database for 25 inner Galaxy globular clusters, employing a new differential reddening mapping technique to improve the clarity of their color-magnitude diagrams.

Contribution

It introduces a novel method for mapping differential reddening, enabling cleaner photometric data for clusters in the obscured inner Galaxy region.

Findings

High-quality photometric data for 25 clusters obtained

Effective differential reddening correction applied

Enhanced color-magnitude diagrams produced

Abstract

Extensive photometric studies of the globular clusters located towards the center of the Milky Way have been historically neglected. The presence of patchy differential reddening in front of these clusters has proven to be a significant obstacle to their detailed study. We present here a well-defined and reasonably homogeneous photometric database for 25 of the brightest Galactic globular clusters located in the direction of the inner Galaxy. These data were obtained in the B, V, and I bands using the Magellan 6.5m telescope and the Hubble Space Telescope. A new technique is extensively used in this paper to map the differential reddening in the individual cluster fields, and to produce cleaner, dereddened color-magnitude diagrams for all the clusters in the database. Subsequent papers will detail the astrophysical analysis of the cluster populations, and the properties of the obscuring material along the clusters' lines of sight.