...

Hubble Fellow.

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... dwarfs

Throughout this work we'll use the term double white dwarf instead of double degenerate, which is commonly used, because the term double degenerate is sometimes used for white dwarf - neutron star or double neutron star binaries.

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... merging

Note, however, that just before merging white dwarfs may become quite bright due to tidal heating (Iben et al. 1998).

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... sample

The P - m distribution does not qualitatively change if we increase $V_{\rm lim}$ by one or two magnitudes, since we still deal with very nearby objects.

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