The White Dwarf Cooling Sequence of the Globular Cluster Messier 4

• DOI: 10.1086/342528
• Publication Date: 2002-09-30T17:28:29Z
• Authors: Brad M. S. Hansen; James Brewer; Greg G. Fahlman; Brad K. Gibson; Rodrigo Ibata; Marco Limongi; R. Michael Rich; Harvey B. Richer; Michael M. Shara; Peter B. Stetson
• Keywords: Astrophysics (astro-ph); 0103 physical sciences; FOS: Physical sciences; Astrophysics; 01 natural sciences; 520

We present the white dwarf sequence of globular cluster M4, based on a 123 orbit Hubble Space Telescope exposure, with limiting magnitude V ~ 30 and I 28. The luminosity function rises sharply for > 25.5, consistent behavior expected burst population. dwarfs M4 extend to approximately 2.5 mag fainter than peak local Galactic disk function. This demonstrates clear significant age difference between halo M4. Using same standard models fit each yields ages 7.3 ± 1.5 Gyr 12.7 0.7 (2 σ statistical errors).