In Einstein ’ s general relativity , gravity is mediated by a massless metric field .
The extension of general relativity to consistently include a mass for the graviton has profound implications for gravitation and cosmology .
Salient features of various massive gravity theories can be captured by Galileon models , the simplest of which is the cubic Galileon .
The presence of the Galileon field leads to additional gravitational radiation in binary pulsars where the Vainshtein mechanism is less suppressed than its fifth-force counterpart , which deserves a detailed confrontation with observations .
We prudently choose fourteen well-timed binary pulsars , and from their intrinsic orbital decay rates we put a new bound on the graviton mass , m _ { g } \lesssim 2 \times 10 ^ { -28 } { eV } / c ^ { 2 } at the 95 % confidence level , assuming a flat prior on \ln m _ { g } .
It is equivalent to a bound on the graviton Compton wavelength \lambda _ { g } \gtrsim 7 \times 10 ^ { 21 } m. Furthermore , we extensively simulate times of arrival for pulsars in orbit around stellar-mass black holes and the supermassive black hole at the Galactic center , and investigate their prospects in probing the cubic Galileon theory in the near future .