Exciting Modes due to the Aberration of Gravitational Waves: Measurability for ExtremeMassRatio Inspirals
Abstract
Gravitational waves from a source moving relative to us can suffer from specialrelativistic effects such as aberration. The required velocities for these to be significant are on the order of 1000 km s^{1}. This value corresponds to the velocity dispersion that one finds in clusters of galaxies. Hence, we expect a large number of gravitationalwave sources to have such effects imprinted in their signals. In particular, the signal from a moving source will have its higher modes excited, i.e., (3,3) and beyond. We derive expressions describing this effect and study its measurability for the specific case of a circular, nonspinning extrememassratio inspiral. We find that the excitation of higher modes by a peculiar velocity of 1000 km s^{1} is detectable for such inspirals with signaltonoise ratios of ≳20 . Using a Fisher matrix analysis, we show that the velocity of the source can be measured to a precision of just a few percent for a signaltonoise ratio of 100. If the motion of the source is ignored, parameter estimates could be biased, e.g., the estimated masses of the components through a Doppler shift. Conversely, by including this effect in waveform models, we could measure the velocity dispersion of clusters of galaxies at distances inaccessible to light.
 Publication:

Physical Review Letters
 Pub Date:
 July 2021
 DOI:
 10.1103/PhysRevLett.127.041102
 arXiv:
 arXiv:2010.15842
 Bibcode:
 2021PhRvL.127d1102T
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 Accepted PRL