Constraining the distance to inspiralling NS-NS with Einstein Telescope

Einstein Telescope (ET) is a planned third generation gravitational waves detector located in Europe. Its design will be different from currently build interferometers, because ET will consist of three interferometers rotated by a 60 deg with respect to each other in one plane. One of the biggest challenges for ET will be to determine sky position and distance to observed sources. If an object is observed in a few interferometers simultaneously one can estimate the position using traingulation from time delays, but so far there are no plans for a network of third generation detectors. Another possibility to deal with that problem is by using multimessenger approach, because redshift and sky position could be recovered from electromagnetic observations. In this paper we present a novel method of estimating distance and position in the sky of merging binaries. While our procedure is not as accurate as the multimessenger method, it can be applied to all observations, not just the ones with electromagnetic counterparts. We have shown that it is possible to significantly improve distance estimates using the measurements of the signal to noise ratio from all three interferometers .