BHI Colloquium

Date: 

Tuesday, February 2, 2021, 1:30pm to 2:30pm

Location: 

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Matthew Lister (Astronomy) - Purdue University

Title: Parsec-Scale Jetted Outflows Powered by Supermassive Black Holes
 
Abstract: A small fraction of active galactic nuclei launch powerful collimated outflows that emit strongly from radio to TeV gamma-rays, and recent evidence suggests they may also be strong neutrino emitters. Because of their relativistic speeds, they can easily outshine their host galaxy when they are oriented toward us. These blazars dominate all-sky surveys in gamma-rays and at short radio wavelengths in regions away from the galactic plane, but many important details of their emission and launching mechanisms are still topics of debate. Blazar jets are a primary target of regular observations with the Very Long Baseline Array, through which we can witness their parsec-scale evolution via time-lapse imaging. The MOJAVE program has monitored over 400 AGN jets to date, and has revealed apparent superluminal motion, standing features, and decade-long oscillatory behavior of energized channels within the flows. The most recent observations are revealing details about jet magnetic field structure using multi-frequency polarization imaging. MOJAVE has found strong correlations with AGN gamma-ray emission detected by NASA's Fermi observatory, which has categorized blazars based on the peak frequency of their synchrotron radiation output. I will also discuss the discovery of a rare young AGN jet system by Fermi, whose gamma-ray emission is not likely influenced by the typical relativistic beaming effects seen in blazars.

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See also: Astronomy