High resolution reddening map in the direction of the stellar system Terzan 5

TL;DR

This study presents the first high-resolution optical extinction map of Terzan 5, revealing patchy dust structures and enabling clearer identification of its multiple stellar populations.

Contribution

The paper introduces a high-resolution reddening map of Terzan 5, improving understanding of its dust distribution and stellar sub-populations.

Findings

Detected patchy extinction structures with variations up to delta E(B-V)=0.67 mag.

Corrected for differential reddening, revealing two distinct red giant branches.

Confirmed the presence of two sub-populations with different iron abundances.

Abstract

We have used optical images acquired with the Hubble Space Telescope to construct the first high-resolution extinction map in the direction of Terzan 5, a peculiar stellar system in the inner bulge of our Galaxy. The map has a spatial resolution of 8" X 8", over a total FoV of 200" X 200". The absorption clouds show a patchy structure on a typical scale of 20" and extinction variations as large as delta E(B-V) = 0.67 mag, especially in the direction of the center of the system. These correspond to an absolute color excess ranging from E(B-V)=2.15 mag, up to 2.82 mag. After the correction for differential reddening, two distinct red giant branches become clearly visible in the color magnitude diagram of Terzan 5 and they well correspond to the two sub-populations with different iron abundances recently discovered in this system.