Pedro Alexandre C. Cunha
FCUP / IA

Abstract
Active galactic nuclei (AGNs) are key drivers of galaxy evolution, influencing star formation and the growth of their host galaxies across cosmic time. However, a significant fraction of AGNs, particularly type II quasars (QSO2s), remain hidden due to heavy obscuration by gas and dust, making it difficult to fully characterise their impact. In this seminar, I will present our recent work aimed at uncovering and understanding this obscured population.
Building on our previous study, where we identified 366 QSO2 candidates using a machine learning framework applied to SDSS and WISE data (with a median redshift of ~1.1), we now focus on characterising their physical properties. Using CIGALE, we estimate relevant physical properties such as star formation rates, stellar masses, AGN luminosities, and AGN fractions.
Our findings reveal a diverse population of AGN-host galaxies at different evolutionary stages. Many sources lie above the star-forming main sequence at their redshift, hinting at a connection between AGN activity and enhanced star formation. We also identify a subset of galaxies that appear quenched, which may point to obscured star formation or feedback from AGN activity. Comparisons with the semi-empirical SPRITZ simulation further support the classification of our sample as obscured AGNs.

2025 May 28, 13:30

IA/U.Porto
Centro de Astrofísica da Universidade do Porto (Classroom)
Rua das Estrelas, 4150-762 Porto