Colloquium: Dr. Adi Foord | Stanford University | KIPAC
In-Person PHYS 401
Location
Physics : 401
Date & Time
February 8, 2023, 11:00 am – 12:00 pm
Description
TITLE: Probing Supermassive Black Hole Growth Across Cosmic Time
ABSTRACT: After decades of supermassive black hole (SMBH) observations, the connection between their triggering into active galactic nuclei (AGN) during galaxy mergers remains incomplete, although AGN are likely key players in the evolution of massive galaxies. Theoretically, there are many reasons to expect a link between galaxy mergers and the accretion of material onto at least one of the central supermassive black holes. Yet, observationally, varied results have led to uncertainty in whether AGN triggering is dependent on environment. One of the best ways to analyze the possible ties between merger environments and SMBH activity is to study systems with unique observational flags of merger-driven SMBH growth -- or, dual AGN. I will present my work quantifying the dual AGN fraction across various times in the Universe, and as a function of redshift. By analyzing available data in wide and deep public X-ray surveys, the dual AGN fraction at both the high-redshift (2.5 < z < 3.5) and low-redshift (z < 0.03) regime can be better constrained. Pairing X-ray results with available multi-wavelength data, we gain insight on how the X-ray activity of interacting AGN depends on their environments. Lastly, I will highlight the capabilities of future high spatial-resolution X-ray observatories, which will revolutionize the field of dual AGN detectability, and our understanding of the role mergers play in AGN triggering.
ABSTRACT: After decades of supermassive black hole (SMBH) observations, the connection between their triggering into active galactic nuclei (AGN) during galaxy mergers remains incomplete, although AGN are likely key players in the evolution of massive galaxies. Theoretically, there are many reasons to expect a link between galaxy mergers and the accretion of material onto at least one of the central supermassive black holes. Yet, observationally, varied results have led to uncertainty in whether AGN triggering is dependent on environment. One of the best ways to analyze the possible ties between merger environments and SMBH activity is to study systems with unique observational flags of merger-driven SMBH growth -- or, dual AGN. I will present my work quantifying the dual AGN fraction across various times in the Universe, and as a function of redshift. By analyzing available data in wide and deep public X-ray surveys, the dual AGN fraction at both the high-redshift (2.5 < z < 3.5) and low-redshift (z < 0.03) regime can be better constrained. Pairing X-ray results with available multi-wavelength data, we gain insight on how the X-ray activity of interacting AGN depends on their environments. Lastly, I will highlight the capabilities of future high spatial-resolution X-ray observatories, which will revolutionize the field of dual AGN detectability, and our understanding of the role mergers play in AGN triggering.
