While ultra-light bosonic dark matter (ULDM) in a Bose-Einstein condensate (BEC) state could naturally account for the central core in some galaxies and resolve the core-cusp problem, the dark matter density distribution in the outer regions of galaxies remains less explored. We propose a trial wavefunction to model the ULDM distribution beyond the BEC core. We derive the corresponding rotation velocity curve, which shows excellent agreement with those of 12 dwarf spheroidal galaxies. The best-fit ULDM particle mass for each dwarf galaxy falls within a strikingly narrow range of m = (1.8−3.2) × 10^−23 eV.
Tian-yao Fang, Ming-Chung Chu, "Constraining Ultra-Light Dark Matter mass with Dwarf Galaxy Rotation Curves" arXiv:2510.12848 (October 14, 2025).
The best fit particle mass is in line with other studies and very close to the average mass-energy of a graviton, if they exist (and gravitons are, of course, bosons).
In general, ultralight bosonic dark matter proposals are are better fit to the data than any of the other dark matter particle models.
Even warm dark matter, in the keV mass range, only barely improves upon failed cold dark matter and ultraheavy dark matter models. Self-interacting dark matter models have also not stood up well against the data from galaxy dynamics.
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Dark Matter Subhalos and Higher Order Catastrophes in Gravitational Wave Lensing
Authors: Luka Vujeva, Jose María Ezquiaga, Daniel Gilman, Srashti Goyal, Miguel Zumalacárregui
Abstract: Gravitational lensing is an invaluable probe of the nature of dark matter, and the structures it forms. Lensed gravitational waves in particular allow for unparalleled sensitivity to small scale structures within the lenses, due to the precise time resolution in combination with the continuous monitoring of the entire sky. In this work, we show two distinct ways of using strongly lensed gravitational waves to identify the presence of dark matter subhalos: \emph{i)} through higher order caustics generating high relative magnification ( ), short time delay image pairs that break the caustic universality relations of single dark matter halos, which occur for percent of strongly lensed events in our cold dark matter models, and \emph{ii)} through the presence of more than three highly magnified images, which occur for percent of the same simulated events. We find that these results are highly sensitive to the concentrations of subhalos in our simulations, and more mildly to their number densities. The presence of low-mass subhalos increases the probability of observing wave-optics lensing in lensed gravitational waves, which is studied by solving the diffraction integral with the stationary phase approximation, as well as numerically. We also report distinct quantitative and qualitative differences in the distributions of relative magnifications and time delays for subhalo populations with increased number densities or concentrations. With the upcoming detection of strongly lensed events by ground- and space- based detectors, comparisons against these simulated distributions will provide insight into the nature of dark matter. △ Less
Submitted 16 October, 2025; originally announced October 2025.
So are self interacting gravitons dark matter particles? Is there a cloud of gravitons in a gravity well that has time dependencies?
@neo Nice article. Thanks for the heads up.
@jd If dark matter is really a non-perturbative or quantum gravity effect, then "dark matter" would look the gravitons which are the quantum equivalent of gravitational fields. This is why that I think that ultralight bosonic dark matter particle theories are really just weak field gravitational effects.
Amen. So we do not need supersymmetry. Things are pulling together.
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