Greybody factor for accelerating rotating BTZ black hole

Abstract We investigate the greybody factor for the accelerating rotating Bañados–Teitelboim–Zanelli (BTZ) black hole in (2+1)-dimensional spacetime. Due to the non-separability of the Klein–Gordon equation induced by the acceleration parameter, we employ an azimuthal-average approximation to derive an effective potential for massless scalar fields. In the low-frequency limit, we solve the radial equation using matched asymptotic expansions near the horizon and in the far region, accounting for rotation via the horizon angular velocity. Our results yield a power-law scaling for the greybody factor, $$\Gamma (\omega ) \propto (\omega - m \Omega _H)^{2\lambda - 1}$$ Γ ( ω ) ∝ ( ω - m Ω H ) 2 λ - 1 , where $$\lambda = \sqrt{\mu ^2 \ell ^2 + 5/4}$$ λ = μ 2 ℓ 2 + 5 / 4 , highlighting deviations from pure blackbody radiation. We discuss implications for Hawking radiation, superradiance in the regime $$\omega < m \Omega _H$$ ω < m Ω H , and the role of acceleration in modifying black hole thermodynamics.