The End of the White Dwarf Cooling Sequence in M4: an efficient approach

Abstract

We use 14 orbits of ACS 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 turn-off (12.0+/-1.4 Gyr).

37 pages, 13 figures (4 in low resolution), 1 table, 2 years of work. ApJ accepted on March 13, 2009