... population

Implicitly, we assume that besides the thick disk WDs, this criterion rejects the "slowest'' thin disk objects as well.

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... volume

Note that this is a purely photometric definition which does not correspond exactly to the analogue quantity adopted for the evaluation of the WD density via the 1/ $V_{\rm max}$ method (Schmidt 1975).

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... redetermined

They adopted CM relations based on theoretical cooling tracks of $0.6~M_\odot$ WDs with H or He atmospheres. This resulted in distances systematically 16% larger (on average) than those in OHDHS.

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... estimated

Casertano et al. (1990) derived ($\sigma_U$, $\sigma_V$, $\sigma_W$, V₀) $\simeq$ (66, 37, 38, -40) $\pm$ 10 km s^-1 from a maximum likelihood analysis of high proper motion stars within 500 pc of the Sun.

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... determined

They estimated a rotation lag of $V_0\simeq -28.3\pm 3.8$ km s^-1 for the "old'' disk component with dispersions ( $\sigma_U, \sigma_V, \sigma_W) \simeq$ $(56.1\pm 3.9,34.2\pm 2.5,31.2\pm 2.5)$ km s^-1.

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... disk

We adopted ( $\sigma_U, \sigma_V, \sigma_W, V_0) \simeq$ (34, 21, 18, -6) km s^-1 from Table 10.4 of Binney & Merrifield (1998).

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