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We use semi-analytical models to study the effects of primordial black hole(PBH) accretion on the cosmic radiation background during the epoch ofreionization ($z\gtrsim 6$). We consider PBHs floating in the intergalacticmedium (IGM), and located inside haloes, where star formation can occur. Forstars with a mass $\gtrsim 25 \rm\ M_{\odot}$, formed in suitable host haloes,we assume they quickly burn out and form stellar remnant black holes (SRBHs).Since SRBHs also accrete material from their surroundings, we consider them tohave similar radiation feedback as PBHs in the halo environment. To estimatethe background radiation level more accurately, we take into account the impactof PBHs on structure formation, allowing an improved modeling of the halo massfunction. We consider the radiation feedback from a broad suite of black holes:PBHs, SRBHs, high-mass X-ray binaries (HMXBs), and supermassive black holes(SMBHs). We find that at $z\gtrsim 30$, the radiation background energy densityis generated by PBHs accreting in the IGM, whereas at lower redshifts, theaccretion feedback power from haloes dominates. We also analyze the total powerdensity by modeling the accretion spectral energy distribution (SED), and breakit down into select wavebands. In the UV band, we find that for $f_{\rm PBH}\lesssim 10^{-3}$, the H-ionizing and Lyman-$\alpha$ fluxes from PBH accretionfeedback do not violate existing constraints on the timing of reionization, andon the effective Wouthuysen-Field coupling of the 21-cm spin temperature ofneutral hydrogen to the kinetic temperature of the IGM. However, in the X-rayband, with the same abundance, PBHs contribute significantly and could accountfor the unresolved part of the cosmic X-ray background.

Distinguishing the impact and signature of black holes from different origins in early cosmic history