Investigating the Star Formation Characteristics of Radio Active Galactic Nuclei
Research Poster Physical Sciences & Mathematics 2025 Graduate ExhibitionPresentation by Bojun Zhang
Exhibition Number 179
Abstract
This study delves into the star formation habits of radio-active galactic nuclei (AGNs) to unravel the connection between supermassive black holes and their host galaxies. By analyzing data from deep surveys spanning the W-CDF-S, ELAIS-S1, and XMM-LSS fields, we gathered comprehensive samples of radio AGNs and mass-complete reference star-forming galaxies. Our mission was to investigate whether star formation in galaxies hosting radio AGNs is boosted or dampened compared to regular star-forming galaxies, particularly at higher redshifts (up to z ~ 3). We calculated the star-forming fractions (the ratio of star-forming galaxies to all galaxies) for both regular galaxies and radio-AGN host galaxies and examined their relationship to galaxy mass and redshift. Our findings reveal that radio AGNs typically inhabit massive galaxies, which naturally have lower star formation rates (SFRs). Moreover, at lower redshifts (z 1), radio AGNs often exhibit suppressed star formation compared to normal star-forming galaxies. However, at higher redshifts or lower stellar masses, radio AGNs often exhibit SFRs comparable to or even surpassing typical star-forming galaxies. Overall, our analysis suggests that while radio AGNs generally suppress star formation at lower redshifts, their presence at higher redshifts or in lower-mass galaxies doesn’t significantly hinder star formation, indicating a more complex relationship between AGN activity and galaxy evolution.
Importance
Understanding how supermassive black holes’ powerful radio jets influence star formation in their host galaxies is crucial to unraveling the mysteries of galaxy evolution. This study offers crucial insights into whether these jets primarily suppress or stimulate star formation, revealing a nuanced relationship that varies with galaxy mass and cosmic epoch. By clarifying this intricate interplay, the research significantly contributes to our understanding of galaxy growth processes and aids in refining theoretical models that predict the coevolution of galaxies and their central black holes across cosmic time.