Date:
Tue, 02/12/202517:00-18:00
Speaker: Shmuel Gilbaum (Racah institute of Physics, HUJI)
Title: AGN Disk Structure and Dynamics of Embedded Objects (PhD talk)
Abstract:
Active galactic nuclei (AGN) accretion disks are fundamental to our understanding of galaxy evolution and supermassive black hole growth, yet standard models face both theoretical challenges to their self-consistency and observational tensions regarding disk stability, size, and variability. Simultaneously, the "AGN channel" has emerged as a promising explanation for the binary black hole mergers observed by LIGO/Virgo/KAGRA, but its physical mechanisms remain uncertain. This lecture will present a new generation of self-consistent AGN disk models that resolve these classical problems by incorporating the dynamical and thermal feedback from an embedded population of stellar-mass black holes. I will first demonstrate how feedback from these accreting black holes stabilizes the disk against fragmentation. Next, I will show how these objects accumulate in "migration traps," leading to hierarchical mergers that can form black holes in the pair-instability mass gap within a predictable AGN luminosity range. Finally, I will introduce a novel two-temperature disk model that, for the first time, successfully reproduces observed AGN spectra, providing constraints on the properties of these hidden black hole populations. This research thus establishes a physical link between the electromagnetic appearance of AGN and their potential as factories for gravitational wave sources, offering a new avenue for multi-messenger exploration.
Zoom link:
https://huji.zoom.us/j/83999403192?pwd=o38m7DX4G5VxSMUF2Woa3oLS4ZuiZ3.1
Meeting ID: 839 9940 3192
Passcode: 506256
Contact: Dima Ofengeim
Title: AGN Disk Structure and Dynamics of Embedded Objects (PhD talk)
Abstract:
Active galactic nuclei (AGN) accretion disks are fundamental to our understanding of galaxy evolution and supermassive black hole growth, yet standard models face both theoretical challenges to their self-consistency and observational tensions regarding disk stability, size, and variability. Simultaneously, the "AGN channel" has emerged as a promising explanation for the binary black hole mergers observed by LIGO/Virgo/KAGRA, but its physical mechanisms remain uncertain. This lecture will present a new generation of self-consistent AGN disk models that resolve these classical problems by incorporating the dynamical and thermal feedback from an embedded population of stellar-mass black holes. I will first demonstrate how feedback from these accreting black holes stabilizes the disk against fragmentation. Next, I will show how these objects accumulate in "migration traps," leading to hierarchical mergers that can form black holes in the pair-instability mass gap within a predictable AGN luminosity range. Finally, I will introduce a novel two-temperature disk model that, for the first time, successfully reproduces observed AGN spectra, providing constraints on the properties of these hidden black hole populations. This research thus establishes a physical link between the electromagnetic appearance of AGN and their potential as factories for gravitational wave sources, offering a new avenue for multi-messenger exploration.
Zoom link:
https://huji.zoom.us/j/83999403192?pwd=o38m7DX4G5VxSMUF2Woa3oLS4ZuiZ3.1
Meeting ID: 839 9940 3192
Passcode: 506256
Contact: Dima Ofengeim