Constraining the mass of the graviton using coalescing black-hole binaries

Abstract

We study how well the mass of the graviton can be constrained from gravitational-wave (GW) observations of coalescing binary black holes. Whereas the previous investigations employed post-Newtonian (PN) templates describing only the inspiral part of the signal, the recent progress in analytical and numerical relativity has provided analytical waveform templates coherently describing the inspiral-merger-ringdown (IMR) signals. We show that a search for binary black holes employing IMR templates will be able to constrain the mass of the graviton much more accurately (∼ an order of magnitude) than a search employing PN templates. The best expected bound from GW observatories (λ_g > 7.8 ×10¹³ km from Advanced LIGO, λ_g > 7.1 ×10¹⁴ km from Einstein Telescope, and λ_g > 5.9 ×10¹⁷ km from LISA) are several orders of magnitude better than the best available model-independent bound (λ_g > 2.8 ×10¹² km, from solar system tests).