Dr. Nico Cappelluti (University of Miami)

Friday, October 7^th, 2022

1 – 2 PM
Venue: PG6 112
 

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 ~106 M⊙, 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 Mbh-σ 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 the James Webb Space Telescope 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.

Short Bio: Prof. Cappelluti  is assistant Professor at the Physics department of University of Miami. He is interested in employing wide field multiwavelength surveys for finding observational proxies of the formation mechanisms of Super Massive Black Holes in the Universe, determining the origin of Cosmic Backgrounds, studying Active Galactic Nuclei (AGN) clustering and investigate the nature of Dark Matter. He obtained his degree in Astronomy from the university of Bologna and a PhD in physics in 2007 from TUM-Munich.  Before joining the faculty at UM he was a postdoc in the Max Planck institute at Garching, a NAF international postdoc fellow at Bologna and a visiting research assistant at the University of Maryland Baltimore County and a YCAA Prize fellow at Yale.