The rate at which a black hole emits particles with energy between ℏ ℏ ω ω and ℏ ℏ ( ω ω + d ω ω ) and with angular momentum quantum numbers ℓ ℓ , m is given by d Γ Γ = σ σ ω ω , ℓ ℓ , m e ℏ ℏ ω ω k T ± ± 1 d ω ω where k is the Boltzmann constant and T is the Hawking temperature of the black hole. The constant in the denominator is 1 for Bosons and -1 for Fermions. The factors σ σ ω ω , ℓ ℓ , m are called the greybody factors of the black hole. For a charged black hole, these factors may also depend on the charge of the emitted particles.