CONSTRAINING WHITE DWARF STRUCTURE AND NEUTRINO PHYSICS IN 47 TUCANAE

• Published in: The Astrophysical journal Vol. 821; no. 1; p. 27
• Main Authors: Goldsbury, R., Heyl, J., Richer, H. B., Kalirai, J. S., Tremblay, P. E.
• Format: Journal Article
• Language: English
• Published: United Kingdom The American Astronomical Society 10.04.2016
• Subjects: Astronomical models; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Atmospheric models; Cooling; DATA ANALYSIS; globular clusters: individual (47 Tuc); Hubble Space Telescope; HYDROGEN; MARKOV PROCESS; MAXIMUM-LIKELIHOOD FIT; methods: data analysis; methods: statistical; MONTE CARLO METHOD; Monte Carlo methods; NEUTRINOS; PARTICLE PRODUCTION; SPACE; STAR EVOLUTION; stars: atmospheres; STELLAR ATMOSPHERES; TELESCOPES; THIN FILMS; WHITE DWARF STARS; white dwarfs
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/0004-637X/821/1/27

ABSTRACT We present a robust statistical analysis of the white dwarf cooling sequence in 47 Tucanae. We combine Hubble Space Telescope UV and optical data in the core of the cluster, Modules for Experiments in Stellar Evolution (MESA) white dwarf cooling models, white dwarf atmosphere models, artificial star tests, and a Markov Chain Monte Carlo sampling method to fit white dwarf cooling models to our data directly. We use a technique known as the unbinned maximum likelihood to fit these models to our data without binning. We use these data to constrain neutrino production and the thickness of the hydrogen layer in these white dwarfs. The data prefer thicker hydrogen layers ( q H = 3.2 × 10 − 5 ) and we can strongly rule out thin layers ( q H = 10 − 6 ) . The neutrino rates currently in the models are consistent with the data. This analysis does not provide a constraint on the number of neutrino species.