  We construct closed-form gravitational waveforms (GWs) with tidal effects for
the coalescence and merger of binary neutron stars. The method relies on a new
set of eccentricity-reduced and high-resolution numerical relativity (NR)
simulations and is composed of three steps. First, tidal contributions to the
GW phase are extracted from the time-domain NR data. Second, those
contributions are employed to fix high-order coefficients in an effective and
resummed post-Newtonian expression. Third, frequency-domain tidal approximants
are built using the stationary phase approximation. Our tidal approximants are
valid from the low frequencies to the strong-field regime and up to merger.
They can be analytically added to any binary black hole GW model to obtain a
binary neutron star waveform, either in the time or in the frequency domain.
This work provides simple, flexible, and accurate models ready to be used in
both searches and parameter estimation of binary neutron star events.
