No Love for black holes: tightest constraints on tidal Love numbers of black holes from GW250114

Abstract

Tidal Love numbers of black holes, zero in classical general relativity for Kerr black holes in vacuum, become non-vanishing in the presence of exotic matter or in alternative theories of gravity, making them a powerful probe of fundamental physics. The gravitational-wave event GW250114, observed with an unprecedented signal-to-noise ratio, provides a unique opportunity to test this prediction. By analyzing this event, we conclude that the data is consistent with the binary black hole hypothesis, and we place a 90\% upper limit on the effective tidal deformability of $\tildeΛ < 34.8$. These bounds imply that any environment surrounding the black holes must contribute less than $\sim 7\times 10^{-3}$ of their mass, and they rule out some models of boson stars. Our findings provide the strongest observational constraints yet on black hole tidal deformability and show that the data remain fully consistent with the Kerr black hole prediction of vanishing tidal Love numbers.

Figures (12)

• Figure 1: (Left) Marginalized posterior distributions for individual tidal deformabilities $\Lambda_i$ and tidal Love numbers $k_2$ for GW250114. Vertical lines indicate 90% credible upper limits. (Right) Marginalized posterior distribution for the effective tidal deformability $\tilde{\Lambda}$. The vertical line shows the 90% credible upper bound.
• Figure 2: Corner plot comparing the posterior distributions for the chirp mass, mass ratio and spins with (red) and without (black) TLNs.
• Figure 3: Comparison of posterior distributions for the orientation and magnitude of the primary (top) and secondary (bottom) spin components, for models with $\Lambda_i = 0$ (black) and $\Lambda_i \neq 0$ (red). A spin angle of zero corresponds to perfect alignment with the orbital angular momentum.
• Figure 4: Value of the TLN as a function of the product $m\mu$ for various models reported in Ref. Cardoso:2017cfl. Shaded regions indicate excluded regions by the results of our analysis.
• Figure 5: Comparison of the phase of the waveform for a non-spinning binary BH system with $m_1= 33.6~M_{\odot}$ and $m_2=32.2~M_{\odot}$ for the vacuum GR case and for the one augmented with TLNs for $\Lambda_1=\Lambda_2=50$ (red) and $\Lambda_1=\Lambda_2=150$ (gray).