Speaker: Eduardo Mario Gutiérrez (CCRG, Rochester Institute of Technology)
Title: Electromagnetic signatures from supermassive black hole binaries approaching merger
Theoretical models predict that when two galaxies merge, the supermassive black holes at their nuclei might end up forming close binary systems of sub-parsec scales. The gravitational waves emitted by these systems are targets of current Pulsar Timing Arrays and of future interferometers as LISA (Laser Interferometer Space Antenna). Unlike most stellar-mass black hole mergers, supermassive black hole binaries (SMBHBs) live and die in gas-rich environments (the cores of galaxies) and they can present similar phenomenology to single AGNs; namely, accretion disks, jets and the subsequent multi-wavelength emission. A detailed knowledge of the main radiation signatures from these systems is crucial to differentiate them from normal AGNs and to identify potential targets for multi-messenger observations. In this talk, I will present new theoretical predictions of the electromagnetic emission from close SMBBHs. Using data from GRMHD simulations of these systems, we produce realistic ray traced images, spectra, and lightcurves at different wavelengths. We explore the influence of the black hole spin, accretion rate, and line-of-sight inclination on these products and identify specific features that may discriminate SMBHBs from normal AGNs.
Speaker: Luciano Combi (Instituto Argentina de Radioastronomia, Rochester Institute of TechnologyI
Title: Accretion onto spinning supermassive black hole binaries
Massive binary black holes (MBBH) are expected to be in the gas-rich environment of galaxies and emit electromagnetic waves through accretion. At close separations, the dynamical spacetime and the non-linear behavior of the plasma make the system fairly complex. For this reason, numerical simulations are key tools to make accurate predictions of Its multi-messenger emission.
In this talk, we present an overview of recent results on general relativistic magnetohydrodynamical simulations of accretion disks around supermassive black hole binaries. First, we introduce a new approximate metric representing two spinning black holes approaching merger. We use this metric to perform long-term simulations of circumbinary disks and mini-disks. We analyze the periodic behavior and orbital motion of the mini-disks, their interaction with the circumbinary disk, and the electromagnetic outflows produced by the black holes. These simulations constitute the first steps to modeling realistic lightcurves and spectra from MBBH with equal masses.
Manuela Campanelli, astrophysicist and Professor of Mathematical Sciences at Rochester Institute of Technology, simulates compact objects in the universe, like black holes and neutron stars. Frontera allows her team of researchers to simulate these complex systems twice as fast as previous systems.
Understanding the influence of distant stars: Manuela Campanelli, professor of astrophysics at Rochester Institute of Technology and director for the Center for Computational Relativity and Gravitation, is using Frontera to develop a simulation to amplify our understanding of gravitational waves. The goal is to explain the origin of the powerful energy bursts that are emitted during a neutron star merger, including the types of electromagnetic signals emitted. Frontera enables Campanelli and her team to perform complex simulations at a speed two or more times faster than what is possible on any local supercomputer.
Computer calculations modeling the gravitational waves LIGO has observed to date and the black holes that emitted the waves. The image shows the horizons of the black holes above the corresponding gravitational wave.
Credit: Teresita Ramirez / Geoffrey Lovelace / SXS Collaboration / LIGO Virgo Collaboration.
Inspired by the Kepler Orrery IV (https://youtu.be/_DnDeBa0KFc).