The State-of-the-art HST Astro-photometric Analysis of the Core of ω Centauri. II. Differential-reddening Map
Abstract
We take advantage of the exquisite quality of the Hubble Space Telescope astro-photometric catalog of the core of ωCen 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 2 × 2 arcsec2 over a total field of view of about 4.‧3 × 4.‧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 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 ωCen, 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.
Based on archival observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2017
- DOI:
- 10.3847/1538-4357/aa705f
- arXiv:
- arXiv:1705.01951
- Bibcode:
- 2017ApJ...842....7B
- Keywords:
-
- globular clusters: individual: NGC 5139;
- Hertzsprung–Russell and C–M diagrams;
- stars: Population II;
- techniques: photometric;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 12 pages, 9 figures (5 in low res), accepted for publication in ApJ