GW241011 is one of the exceptional binary events detected to present date by the Ligo-Virgo-KAGRA collaboration. This gravitational-wave event features an asymmetric mass ratio, a highly spinning primary (the more massive object in a binary is called a primary) and a relatively low total binary mass. Additionally, GW241011 was observed with high signal-to-noise ratio, making it a perfect laborary to test the nature of the primary and see how well it could be described by the Kerr hypothesis (i.e. is it a Kerr black hole or something more exotic?). In our publication, we address this question by considering the measurement of a spin-induced quadrupole moment from GW241011 and comparing it to the predictions of various exotic compact objects. Spin-induced quadrupole moment sounds like a mouthful, but it is a property of a spacetime reponsible for describing the distortion of a spinning compact object when it rotates. It is measured by a special number, which is unique for Kerr black holes but may be different for other compact object proposals that could act as their replacements. The results of our publication can be summarised as follows. First, we have obtained the most stringent constraint known to date on the spin-induced quadrupole moment. Second, our analysis enabled us to weed out certain exotic proposals that cannot explain the nature of the primary of GW241011 and place an upper bound on the compactness. Check out our interview in the recent press release here.
We were interviewed for a couple of artciles based off our publication in Physical Review Letters. In this work we simulate with high-precision the inspiral, merger and ringdown of binaries consisting of two non-spinning boson stars. The accuracy and longevity of gravitational wave signals generated in the process is sufficient to perform gravitational wave analysis and assess the impact of a hypothetical boson star signal on gravitational wave observations. Our results show that boson star binaries may be detected with present gravitational wave detectors, however whether they can be completely distinguished from binaries of black holes and neutron stars, is a more complicated question. In a nutshell, we demonstrate how sufficiently compact boson star binaries can be very easily mistaken for binary black holes, whilst more 'dilute' systems can stand out as sore thumbs in the data, exhibiting smoking-gun features. If this sounds interesting, I encourage you to checkout our interviews and artciles about our work below:
(i) Interview for the New Scientist: "Signals from exotic new stars could hide in gravitational wave data".
(ii) Interview for Plus: "Boson stars: Beyond vanilla".
(iii) Our work has also featured on the Faculty of Mathematics Insights.
I illustrated a series of comics on "A day in the life of a physicist" and a magical story of mice doing science. See here to view the illustrations.