Studies of active galactic nuclei (AGN) in the local Universe have uncovered a complex tapestry of interactions between growing supermassive black holes (SMBHs) and their host galaxies. As the era of Cosmic Dawn and Cosmic Noon fades into the rearview mirror of cosmic time, the local Universe offers a critical laboratory to dissect the long-term consequences of AGN feedback—both subtle and dramatic—on galactic evolution. But how robust is our understanding of AGN feedback in the relatively tranquil present-day cosmos? What clues can nearby galaxies provide about the mechanisms that have shaped galaxy evolution over the past billions of years?

 

From driving outflows of cold gas to regulating star formation and sculpting galactic morphologies, AGN feedback remains a central pillar of modern galaxy evolution theory. Yet, the diversity of feedback modes—ranging from powerful relativistic jets in radio-loud AGN to the radiatively driven winds of their quasar cousins—has challenged efforts to pin down their precise role in transforming galaxies. The local Universe, rich in observable detail and accessible multi-wavelength datasets, allows us to examine feedback processes at unprecedented resolution.

 

The interplay between AGN-driven feedback and the interstellar medium (ISM) of local galaxies is a nuanced dance, where the impact depends not only on the AGN’s intrinsic properties but also on the host galaxy’s structure, star formation activity, and environment. Observations of molecular gas reservoirs disrupted by AGN winds, quenching of star formation in early-type galaxies, and the role of radio jets in heating the circumgalactic medium (CGM) collectively highlight the multifaceted nature of feedback. However, the extent to which AGN feedback serves as a universal mechanism versus a context-dependent phenomenon remains an open question.

 

As we map the nearby Universe in greater detail through observatories like ALMA, Hubble, James Webb, and Chandra, the challenge lies in connecting the dots between local feedback signatures and their far-reaching implications. Are AGN primarily suppressing star formation, or can they trigger bursts of activity in specific conditions? What role do environmental factors, such as cluster membership or galaxy interactions, play in amplifying or muting feedback effects?

 

Consensus is growing that the study of AGN feedback in the local Universe is not merely a retrospective exercise but a key to unlocking the legacy of cosmic evolution. By probing the interplay between SMBHs and their hosts with a forensic level of detail, we edge closer to answering one of the most profound questions in astrophysics: how do black holes shape the galaxies—and the Universe—that surround them?