Seminari

Supermassive Black Holes and Their Host Galaxies

Vardha Bennert

15-10-2024 - 15:00
Via della Vasca Navale 84 - Aula C

 

Supermassive black holes (BHs) are ubiquitous in the center of massive galaxies. When actively growing through accretion, Active Galactic Nuclei (AGNs) become some of the brightest objects in the universe. It has been two decades that relations between BH mass and the properties of their host galaxies (such as luminosity, stellar mass and stellar velocity dispersion) were first discovered. Interpreted as evidence for a co-evolution between BHs and galaxies, these scaling relations remain a hot topic for contemporary studies with many open questions remaining, including the role of AGN feedback or hierarchical merging, and the nature of the host galaxies. Studying the co-evolution as a function of cosmic history can shed light onto origin and fundamental drivers, but relies on AGNs for which host-galaxy properties are intrinsically difficult to measure, especially at higher redshift. Thus, a local baseline of the MBH-scaling relations for AGN is the key. I will discuss recent progress made possible through integral-field spectroscopy that allows for a robust measurement of stellar-velocity dispersion. While reverberation mapping has been the gold standard for BH mass measurements in AGNs, traditional methods yield only sample-average recipes for BH mass estimates. Recent advances include resolving the broad emission around AGNs spatially: (i) by dynamical modeling of reverberation-mapped data and (ii) through spectro-astronometry with GRAVITY/VLTI. The combination of both leads not only to a full 3D view of the BLR, important for accurately measuring BH mass, it even allows to measure absolute geometric distance to the AGN. In this talk, I will review our understanding of the nature and origin of the scaling relations between supermassive black holes and their host galaxies, and outline new directions.
org: RICCI Federica

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