The Ages of the Thin Disk, Thick Disk, and the Halo from Nearby White Dwarfs

Understand

We present a detailed analysis of the white dwarf luminosity functions derived from the local 40 pc sample and the deep proper motion catalog of Munn et al (2014, 2017).

• Many of the previous studies ignored the contribution of thick disk white dwarfs to the Galactic disk luminosity function, which results in an erronous age measurement.
• We demonstrate that the ratio of thick/thin disk white dwarfs is roughly 20\% in the local sample.
• Simultaneously fitting for both disk components, we derive ages of 6.8-7.0 Gyr for the thin disk and 8.7 $\pm$ 0.1 Gyr for the thick disk from the local 40 pc sample.