Preprint typeset using LATEX style emulateapj v. 12/16/11 CONSTRAINING PARAMETERS OF WHITE-DWARF BINARIES USING GRAVITATIONAL-WAVE AND ELECTROMAGNETIC OBSERVATIONS

The space-based gravitational wave (GW) detector, evolved Laser Interferometer Space Antenna (eLISA) is expected to observe millions of compact Galactic binaries that populate our Milky Way. GW measurements obtained from the eLISA detector are in many cases complimentary to possible electro-magnetic (EM) data. In our previous papers, we have shown that the EM data can significantly enhance our knowledge of the astrophysically relevant GW parameters of the Galactic binaries, such as the amplitude and inclination. This is possible due to the presence of some strong correlations between GW parameters that are measurable by both EM and GW observations, for example the inclination and sky position. In this paper, we quantify the constraints in the physical parameters of the white-dwarf binaries, i.e. the individual masses, chirp mass and the distance to the source that can be obtained by combining the full set of EM measurements such as the inclination, radial velocities, distances and/or individual masses with the GW measurements. We find the following 2−σ fractional uncertainties in the parameters of interest. The EM observations of distance constrains the the chirp mass to ∼ 15 − 25%, whereas EM data of a single-lined spectroscopic binary constrains the secondary mass and the distance with factors of 2 to ∼ 40%. The single-line spectroscopic dat