Differential reddening in 21 globular clusters

Here, we estimate local reddening variations in the direction of 56 Galactic GCs. To do that, we use the public catalogues derived as part of the Hubble Space Telescope UV Legacy Survey of Galactic GCs, which include photometry in the F275W, F336W, F438W, F606W, and F814W filters.

We corrected photometry for differential reddening and found that for 21 out of 56 GCs the adopted correction procedure significantly improved the CMDs. Moreover, we measure the reddening law in the direction of these clusters, finding that R_V_ exhibits a high level of variability within the Galaxy, ranging from ~2.0 to ~4.0. The updated values of R_V_ have been used to improve the determination of local reddening variations and derive high-resolution reddening maps in the direction of the 21 highly-reddened targets within our sample.