We want more! With gravitational-wave data, some quantities like the masses of the black holes are much easier to see than others. But those others are very interesting, notably spins that process and orbits that are eccentric, because they would tell us how black hole binaries came to be in the first place. So while it would be great to see those, it’s also being very hard. Some tentative claims have been made with current data, but nothing unambiguous so far. In this paper led by Isobel from Cambridge, we show that (surprise surprise…) the signals needs to be long enough before one can tell eccentricity and spin precession apart.

Isobel Romero-Shaw, Davide Gerosa, Nicholas Loutrel.
Monthly Notices of the Royal Astronomical Society 519 (2023) 5352–5357.
arXiv:2211.07528 [astro-ph.HE].