Year: 2026
Type: preprint
Abstract: Many well-motivated dark matter (DM) scenarios, including dark photon DM, axion-like particles, sterile neutrinos, and primordial black holes, can deposit energy into ordinary matter and significantly raise the thermal energy of astrophysical gas. We present a simple, model-independent implementation of DM-induced heating in the RAMSES hydrodynamic simulation code, parameterized by an effective local heat-transfer rate $Γ_{\rm heat}$. Using simulations of an isolated gas-rich dwarf galaxy with properties similar to WLM, we find that DM heating substantially alters the thermal structure of the circumgalactic medium (CGM) while leaving the star formation rate and the dense ISM nearly unchanged. For $Γ_{\rm heat} = 10^{-27}$ to $10^{-25}\ {\rm s}^{-1}$, the neutral hydrogen column at 10 kpc is suppressed by 0.6 to 3.9 dex relative to the control simulation. Similarly, the C II and Si II column densities decrease by 4.1 and 5.5 dex, and by 2.2 and 3.0 dex for C IV and Si IV. These signatures are accessible to quasar absorption-line spectroscopy, so CGM observations of nearby field dwarf galaxies provide a promising avenue for constraining dark matter models that inject heat into ordinary matter.
Source: arXiv (Cornell University)
Institution: Princeton University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W7213326811