LISA verification binaries with updated distances from Gaia Data Release 2

Ultracompact binaries with orbital periods less than a few hours will dominate the gravitational wave signal in the mHz regime. Until recently, 10 systems were expected have a predicted gravitational wave signal strong enough to be detectable by the Laser Interferometer Space Antenna (LISA), the so-called 'verification binaries'. System parameters, including distances, are needed to provide an accurate prediction of the expected gravitational wave strength to be measured by LISA. Using parallaxes from Gaia Data Release 2 we calculate signal-to-noise ratios (SNR) for approximate to 50 verification binary candidates. We find that 11 binaries reach a SNR >= 20, two further binaries reaching a SNR >= 5 and three more systems are expected to have a SNR approximate to 5 after four years integration with LISA. For these 16 systems we present predictions of the gravitational wave amplitude (A) and parameter uncertainties from Fisher information matrix on the amplitude (A) and inclination (i).