Collaborative Research: WoU-MMA: Multi-scale and multi-messenger modeling of jets in active galactic nuclei

Northwestern University, Evanston IL

Investigators

Abstract

Part 1 Galaxies are vast collections of hundreds of billions of stars. In a minority of the galaxies their observed light is dominated by a single source: the supermassive black hole located at their very center. In these galaxies, the black hole feeds on material which turns into very hot ionized gas or plasma. Surprisingly, part of this material is ejected away from the black hole forming narrow beams of plasma that move at near the speed of light. These beams, when directed at Earth, make some of the brightest and extreme sources ever observed in the Universe. The proposing team plans to perform the largest numerical simulations to study how matter falls from the vast scale of the galaxy into the tiny scale of the black hole and follow how the narrow fast beams of plasma form and shine as they propagate through the galaxy. The results from the numerical simulations will be publicly accessible through a user-friendly, interactive website. The user (scientist, teacher or high-school student) will be able to generate images of these beams in real-time and will thus be exposed to an exciting field of modern high-energy astrophysics. Part 2 Recent detection by the IceCube Neutrino Observatory of a very high energy neutrino event coincident with multi-wavelength flaring of blazar TXS 0506+056 strongly suggests that blazars do not only produce high-energy photons but also ultra-high-energy cosmic rays and neutrinos. This exciting multi-messenger discovery motivates a detailed study of relativistic jet physics, to interpret this and upcoming multi-messenger observations of active galactic nuclei (AGN). The team proposes to perform multi-scale jet simulations that connect accretion physics, fluid dynamics, particle acceleration, and radiative transfer, to study the multi-wavelength polarized radiation signatures and neutrinos from AGN jets. The team plans to perform the largest to date general relativistic magnetohydrodynamic simulations of AGN accretion and jets, extending from the black hole to the blazar emission zone. They will use first-principle kinetic plasma simulations to calculate particle acceleration in jet dissipation zones and build comprehensive multi-messenger polarized radiative transfer that includes all the relevant physics. In this way, the team can bridge the gap between first-principle modeling and multi-messenger observations, and advance the understanding of AGN jet physics responsible for multi-messenger emission. The team will disseminate the results to the public through an immersive website, train high-school students, and organize a summer school in compact objects for graduate students, where participants will work on theoretical and/or numerical problems at the forefront of the research field. This award addresses/advances the goals of the Windows on the Universe Big Idea. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.