The End of the White Dwarf Cooling Sequence in M4: An Efficient Approach
Anderson, Jay; Salaris, Maurizio; Bedin, Luigi R.; Piotto, Giampaolo; King, Ivan R.; Cassisi, Santi
United States, United Kingdom, Italy
Abstract
We use 14 orbits of Advanced Camera for Surveys observations to reach the end of the white dwarf cooling sequence in the globular cluster M4. Our photometry and completeness tests show that the end is located at magnitude m F606W = 28.5 ± 0.1, which implies an age of 11.6 ± 0.6 Gyr (internal errors only). This is consistent with the age from fits to the main-sequence turnoff (12.0 ± 1.4 Gyr).
Based on 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, under GO-10146.