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AR 12656 (Archival Research)

Sun Mar 1 18:32:25 EST 2015

Principal Investigator: Jay Anderson
PI Institution: Space Telescope Science Institute
Investigators (xml)

Title: THE ULTIMATE CATALOG OF OMEGA CENTAURI: 15-BAND PHOTOMETRY AND PROPER MOTIONS
Cycle: 19

Abstract
We propose to construct the most comprehensive catalog of photometry and proper motions ever assembled for a globular cluster {GC}. The core of Omega Centauri has been imaged nearly 500 times through WFC3's UVIS and IR channels for the purposes of detector calibration. There exist ~30 exposures through each of 15 filters, stretching uniformly from F225W in the UV to F160W in the infrared. Furthermore, the 8-year baseline between this data and a 2002 ACS survey will more than double the accuracy and triple the number of well-measured stars compared to our previous groundbreaking effort. This totally unprecedented complete spectral coverage for over 300,000 stars, from the red-giant branch {RGB} down to the white dwarfs {WDs}, provides the best chance yet to understand the multiple-population phenomenon in any GC. A preliminary analysis of the color-magnitude diagrams in different bands already allows us to identify more than 10 distinct sequences. We will make the full catalog of 15-band photometry and proper motions available to the community within 6 months of starting this project. We will then be the first to exploit this tremendous resource. The science we will address includes: {1} identifying all the sequences and tying them together, from the main sequence up to the RGB; {2} continuing the search for a central massive object; {3} examination of the WD sequence for any manifestations of multiple-populations; and {4} searching for cataclysmic variables and He WDs.