Year: 2026
Type: preprint
Abstract: Extensive Euclid satellite imaging at low surface brightness has revealed that most nearby galaxies are diffuse-looking spheroids, where the stellar radius increases for over three decades in luminosity. We argue this Diffuse Galaxy sequence results from internal stellar diffusion by Wave Dark Matter ($ψ$DM), as wave energy is transferred to star orbits over time. In particular, the soliton random motion scatters central stars onto radial orbits that become enhanced with each passage through the centre, slowly ``puffing up" the stellar profile. Heating is greater within massive galaxies as $ψ$DM fluctuations are stronger and more frequent, reproducing both the Diffuse Galaxy sequence and the rising velocity dispersion along the sequence, from Ultra-Faint to Dwarf Spheroidal and Ultra Diffuse galaxies, favouring a light boson, $m_ψ=2.88^{+0.14}_{-0.13}\times10^{-22}$eV. Winding back this diffusion, we predict the stellar content of Diffuse Galaxies, including globular clusters, formed near the centre, as anticipated by $ψ$DM simulations, where gas cools efficiently within the dense soliton. This predicted $ψ$DM evolution from compact beginnings towards diffuse spheroidal galaxies today can now be fully charted from JWST to Euclid.
Source: arXiv (Cornell University)
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1175115578, Dark UNiverse Explorations, Hubble constant measurements with cluster-scale gravitationally lensed quasars and supernovae, G2262748287, G294895050, G300979063, G3480869486, G3840207496, G425668148, G464105488, G5080475149, Comprehensive understanding of the formation history of structures in the Universe, G7084143925, 古代説話における諸寺縁起の研究, G8590477180
OpenAlex ID: W7212233097