A Deep, Wide-Field, and Panchromatic View of 47 Tuc and the SMC with HST: Observations and Data Analysis Methods

Abstract

In HST Cycle 17, we imaged the well known globular star cluster 47 Tucanae for 121 orbits using ACS and both the UVIS and IR channels of WFC3 (GO-11677, PI - H. Richer). This unique data set was obtained to address many scientific questions that demand a very deep, panchromatic, and panoramic view of the cluster's stellar populations. In total, the program obtained over 0.75 Ms of imaging exposure time with the three HST cameras, over a time span of 9 months in 2010. The primary ACS field was imaged in the two broadband filters F606W and F814W filters, at 13 orientations, for all 121 orbits. The parallel WFC3 imaging provides a panchromatic (0.4 - 1.7 micron) and contiguous imaging swath over a 250 degree azimuthal range at impact radii of 6.5 -- 17.9 pc in 47 Tuc. This imaging totals over 60 arcmin^2 in area and utilizes the F390W and F606W broadband filters on WFC3/UVIS and the F110W and F160W broadband filters on WFC3/IR. In this paper, we describe the observational design of the new survey and one of the methods used to analyze all of the imaging data. This analysis combines over 700 full-frame images taken with the three HST cameras into a handful of ultra-deep, well-sampled combined images in each of the six filters. The results reveal unprecedented color-magnitude diagrams (CMDs) of the cluster extending to >30th magnitude in the optical, 29th magnitude in the UV, and 27th magnitude in the IR. The data set provides a characterization of the complete stellar populations of 47 Tuc, extending from the faintest hydrogen burning dwarfs through the main-sequence and giant branches, down to very cool white dwarf remnants in the cluster. The imaging also provides the deepest probe of the stellar populations of the background Small Magellanic Cloud (SMC) galaxy, resolving low mass main-sequence dwarfs with M < 0.2 Msun.

Accepted for Publication in the Astronomical Journal. 23 pages, 13 figures, and 4 tables. Companion paper by K. Woodley is astro-ph/0374778

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• The White Dwarf Cooling Sequence of NGC6397
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Cited by in corpus (37)

• Improving PARSEC models for very low mass stars
• The updated BaSTI stellar evolution models and isochrones: II. alpha-enhanced calculations
• Extended Main Sequence Turnoffs in Intermediate-Age Star Clusters: A Correlation Between Turnoff Width and Early Escape Velocity
• An Age Difference of 2 Gyr between a Metal-Rich and a Metal-Poor Globular Cluster
• A Dynamical Signature of Multiple Stellar Populations in 47 Tucanae
• The Age of the Milky Way Inner Halo
• New PARSEC database of alpha-enhanced stellar evolutionary tracks and isochrones I. Calibration with 47 Tuc (NGC104) and the improvement on RGB bump
• Ultra-Deep Hubble Space Telescope Imaging of the Small Magellanic Cloud: The Initial Mass Function of Stars with M <~ 1 Msun
• The Spectral Energy Distributions of White Dwarfs in 47 Tucanae: The Distance to the Cluster
• Stellar Models of Multiple Populations in Globular Clusters. I. The Main Sequence of NGC 6752
• Constraining Globular Cluster Age Uncertainties Using the IR Color-Magnitude Diagram
• An extended main sequence turn-off in the Small Magellanic Cloud star cluster NGC411
• New Clues to the Cause of Extended Main Sequence Turn-Offs in Intermediate-Age Star Clusters in the Magellanic Clouds
• Constraining Neutrino Cooling using the Hot White Dwarf Luminosity Function in the Globular Cluster 47 Tucanae
• A comparative analysis of the observed white dwarf cooling sequence from globular clusters
• New Constraints on the Star Formation History of the Star Cluster NGC 1856
• 11-12 Gyr old White Dwarfs 30 parsecs Away
• The white dwarf cooling sequence of 47 Tucanae
• The Age of the Old Metal-Poor Globular Cluster NGC6397 Using WFC3/IR Photometry
• Deep HST Imaging in 47 Tucanae: A Global Dynamical Model
• Comparing the White Dwarf Cooling Sequences in 47 Tuc and NGC 6397
• A New Approach to Convective Core Overshooting: Probabilistic Constraints from Color-Magnitude Diagrams of LMC Clusters
• An Empirical Measure of the Rate of White Dwarf Cooling in 47 Tucanae
• Formation and Evolution of Blue Stragglers in 47 Tucanae
• The HST Large Programme on NGC 6752. III. Detection of the Peak of the White Dwarf Luminosity Function
• JWST unveils the brown dwarf sequence of 47 Tucanae
• The M4 Core Project with HST --- I. Overview and First-Epoch
• Dynamical estimate of post main sequence stellar masses in 47 Tucanae
• On the use of the main sequence knee (saddle) to measure globular cluster ages
• The VMC Survey. XVIII. Radial dependence of the low-mass, 0.55--0.82 $M_{\odot }$ stellar mass function in the Galactic globular cluster 47 Tucanae
• Modeling Gas Evacuation Mechanisms in Present-Day Globular Clusters: Stellar Winds from Evolved Stars and Pulsar Heating
• Tests of photometry: the case of the NGC 3370 ACS field
• New Halo White Dwarf Candidates in the Sloan Digital Sky Survey
• The GeMS/GSAOI Galactic Globular Cluster Survey (G4CS) II: Characterization of 47 Tuc with Bayesian Statistics
• The Onset of Convective Coupling and Freezing in the White Dwarfs of 47 Tucanae
• The Cooling of Old White Dwarfs in 47 Tucanae
• Gravitational Microlensing Rates in Milky Way Globular Clusters