GW190521 may be an intermediate mass ratio inspiral

GW190521 was the first confident gravitational wave observation with a total mass greater than 100 solar masses. Initial estimates of the initial black holes place one or both of them in the upper mass gap produced by pair-instability in supernovae (~50-120 solar masses). We re-analyze GW190521 and find that there are additional modes in the mass distribution which are consistent with both black holes existing outside this mass gap, with the most likely parameters consistent with a ~16 solar mass black hole merging with a 170 solar mass black hole. I'll discuss these results and the implications for the history of GW190521.