AstroLunch @ CMU: Cindy Yuexing Gulis (PSU)

May 3, 2024 - 12:00pm to 1:00pm

12:00 PM – 8330 Wean Hall (CMU) and Zoom


Probing the Early Universe with the Most Distant Quasars

To date, more than 200 quasars have been detected at redshift z>6, with the most distant one being reported by JWST at z~10.6. These distant quasars are believed to harbor supermassive black holes of ~106-9 Msun. These observations present challenges to the standard cosmological model to explain the early formation of SMBHs and host galaxies within the first billion years after the Big Bang. Here I present results of a comprehensive study that combines cosmological simulations and radiative transfer calculations to probe the formation, evolution, and multi-wavelength properties of the first black holes and their host galaxies. We find that light seeds of ~102 Msun from PopIII stars can grow to ~105 Msun by redshift z~6 via super-critical accretion, while heavier seeds of ≳ 103  Msun can reach ~107-9 via rapid accretion facilitated by gas-rich galaxy mergers and self-regulated by feedback. The quasar hosts are star-forming galaxies that show diversity in galaxy properties and environments, and the BH – galaxy correlations at z>6 deviate those from the local universe. Finally, the galaxy luminosity functions in UV and emission lines such as Lya, [CII] and [OIII] at z>10 from our study will provide constrains on the cosmic reionization history, and we predict that JWST and ALMA may be able to detect young quasars at redshift z>15.