# The State-of-the-Art HST Astro-Photometric Analysis of the core of   $\omega$ Centauri. I. The Catalog

**Authors:** A. Bellini (1), J. Anderson (1), L. R. Bedin (2), I. R. King (3), R., P. van der Marel (1), G. Piotto (2,4), A. M. Cool (5) ((1) STScI, (2), INAF-Pd, (3) Univ. Washington, (4) UNIPD, (5) San Francisco State Univ.)

arXiv: 1704.07425 · 2017-06-21

## TL;DR

This paper presents a comprehensive, multi-epoch, multi-filter catalog of over 470,000 stars in the core of $	ext{omega}$ Centauri, combining 11 years of data to enhance proper-motion accuracy and spectral coverage for studying multiple stellar populations.

## Contribution

It provides the most complete astro-photometric catalog for $	ext{omega}$ Centauri's core, including detailed data reduction and calibration methods, and significantly improves proper-motion measurements.

## Key findings

- Over 470,000 stars cataloged with multi-band photometry.
- Proper-motion accuracy more than doubled over previous data.
- Spectral coverage from UV to infrared for detailed stellar analysis.

## Abstract

We have constructed the most-comprehensive catalog of photometry and proper motions ever assembled for a globular cluster (GC). The core of $\omega$Cen has been imaged over 650 times through WFC3's UVIS and IR channels for the purpose of detector calibration. There exist from 4 to over 60 exposures through each of 26 filters, stretching continuously from F225W in the UV to F160W in the infrared. Furthermore, the 11-year baseline between these data and a 2002 ACS survey has allowed us to more than double the proper-motion accuracy and triple the number of well-measured stars compared to our previous groundbreaking effort. This totally unprecedented complete spectral coverage for over 470,000 stars within the cluster's core, from the tip of the red-giant branch down to the white dwarfs, provides the best astro-photometric observational data base yet to understand the multiple-population phenomenon in any GC. In this first paper of the series we describe in detail the data-reduction processes and deliver the astro-photometric catalog to the astronomical community.

## Full text

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## Figures

19 figures with captions in the complete paper: https://tomesphere.com/paper/1704.07425/full.md

## References

38 references — full list in the complete paper: https://tomesphere.com/paper/1704.07425/full.md

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Source: https://tomesphere.com/paper/1704.07425