Wave Cold Dark Matter Can Reproduce the Radial Acceleration Relation in X-ray Elliptical Galaxies

Wave cold dark matter (wave CDM) is a well-motivated variant within the collisionless CDM paradigm, in which the de~Broglie wavelengths of ultralight bosons become relevant on galactic scales. While many of the previous tests of wave CDM have focused on small-scale tensions involving solitonic cores and certain soliton–halo relations in galaxies, the radial acceleration relation (RAR) provides a complementary test: for a given baryonic mass distribution, it probes whether the DM halo can reproduce the observed total gravitational field. In this work we test wave CDM against the RAR using eight X-ray elliptical galaxies from the compilation of Lelli et al. We perform a suite of 3D Schrödinger–Poisson simulations and evolve the wave-CDM halos to virialized quasi-stationary states. For each galaxy and each adopted boson mass, we select the realization whose final snapshot most closely matches the empirical RAR. We find that the selected wave-CDM realizations for these elliptical galaxies can reproduce the RAR without including baryonic feedback or dark-matter self-interactions. At the boson mass $m_a={10}^{-23}$eV, the combined fit to the eight galaxies gives $a_0=1.19\times {10}^{-10}\mathrm{m}{\mathrm{s}}^{-2}$, consistent with the canonical value inferred from disk galaxies. When the boson mass is varied over $3\times {10}^{-24}$ eV $\le m_a\le 2\times {10}^{-23}$ eV, the best-fit value of $a_0$ changes by only $\sim 11\mathrm{\%}$, and this variation shows no systematic trend with $m_a$. This insensitivity to boson mass arises because, over the radial range relevant for the RAR, the virialized halos are supported mainly by their velocity field, whereas the boson-mass-dependent quantum-pressure term is dynamically subdominant. These results show that wave CDM can reproduce the RAR in elliptical galaxies, and provide a new galactic-scale test of the model beyond the previous focus on solitonic cores.