Title: Understanding Dark Matter and SMBH seeds in the early Universe. Primordial Black Holes and new missions.
Speaker: Prof. Nico Cappelluti (University of Miami, USA)
Abstract: We explore the observational implications of a model in which primordial black holes (PBHs) with a broad birth mass function ranging in mass from a fraction of a solar mass to ~10^6 solar masses, consistent with current observational limits, constitute the dark matter component in the Universe. PBH DM could also provide a channel to make early black hole seeds and naturally account for the origin of an underlying dark matter halo - host galaxy and central black hole connection that manifests as the M_BH-sigma correlation. To estimate the luminosity function and contribution to integrated emission power spectrum from these high-redshift PBH DM halos, we develop a Halo Occupation Distribution (HOD) model. In addition to tracing the star formation and reionizaton history, it permits us to evaluate the Cosmic Infrared and X-ray Backgrounds (CIB and CXB). We find that accretion onto PBHs/AGN successfully accounts for the detected backgrounds and their cross-correlation, with the inclusion of an additional IR stellar emission component. Detection of the deep IR source count distribution by JWST could reveal the existence of this population of high-redshift star-forming and accreting PBH DM. I will then explore scenarios in which a possible NASA X-ray imaging probe, AXIS, could unveil the nature of early black holes.