# The State-of-the-Art HST Astro-Photometric Analysis of the core of $\omega$ Centauri. II. Differential-Reddening Map

## TL;DR

This paper presents a high-resolution differential-reddening map of the core of omega Centauri using Hubble Space Telescope data, revealing small-scale extinction variations crucial for studying stellar populations.

## Contribution

It introduces a novel high-precision, high-resolution differential-reddening map of omega Centauri's core, enhancing understanding of its stellar populations and foreground extinction.

## Key findings

- Differential reddening varies by up to ±10% within the core.
- Map resolution is 2x2 arcseconds over 4.3'x4.3' field.
- Reddening estimates are consistent within 0.1% across methods.

## Abstract

We take advantage of the exquisite quality of the Hubble Space Telescope astro-photometric catalog of the core of wCen presented in the first paper of this series to derive a high-resolution, high-precision, high-accuracy differential-reddening map of the field. The map has a spatial resolution of 2x2 square arcsecs over a total field of view of about 4.3'x4.3'. The differential reddening itself is estimated via an iterative procedure using five distinct color-magnitude diagrams, which provided consistent results to within the 0.1% level. Assuming an average reddening value E(B-V)=0.12, the differential-reddening within the cluster's core can vary by up to +/- 10%, with a typical a standard deviation of about 4%. Our differential-reddening map is made available to the astronomical community in the form of a multi-extension FITS file. This differential-reddening map is essential for a detailed understanding of the multiple stellar populations of wCen, as presented in the next paper in this series. Moreover, it provides unique insight into the level of small spatial-scale extinction variations in the Galactic foreground.