The present work derived the robust constraints on annihilating weakly interacting massive particle (WIMP) parameters utilizing new radio observations of M31 as well as new studies of its dark matter distribution and other properties. The characteristics of emission due to dark matter (DM) annihilation were computed in the frame of a 2D galactic model employing GALPROP code adapted specifically for M31. This enabled us to refine various inaccuracies of previous studies on the subject. DM constraints were obtained for two representative annihilation channels: $\chi \chi \to b\overline{b}$ and $\chi \chi \to {\tau }^{+}{\tau }^{-}$. A wide variety of radio data was utilized in the frequency range $\approx (0.1–10)\mathrm{GHz}$. As the result, the thermal WIMP lighter than fiducially $\approx 70\mathrm{GeV}$ for $b\overline{b}$ channel and $\approx 40\mathrm{GeV}$ for ${\tau }^{+}{\tau }^{-}$ was excluded. The corresponding mass threshold uncertainty ranges were estimated to be 20–210 GeV and 18–89 GeV. The obtained exclusions are competitive to those from Fermi-LAT observations of dwarfs and AMS-02 measurements of antiprotons. Our constraints do not exclude the explanation of the $\gamma$-ray outer halo of M31 and the Galactic Center excess by annihilating DM. The thermal WIMP with $m_x\approx 70\mathrm{GeV}$, which explains the outer halo, would make a significant contribution to the nonthermal radio flux in M31 nucleus, fitting well both the spectrum and morphology. And, finally, we questioned the possibility claimed in other studies to robustly constrain heavy thermal WIMP with $m_x>100\mathrm{GeV}$ by radio data on M31.

• Received 4 May 2022
• Accepted 7 July 2022

DOI:https://doi.org/10.1103/PhysRevD.106.023023