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Preliminary Exam
IceCube and Neutrino Astronomy
Date: Monday, November 30th
Time: 2:00 pm - 4:00 pm
Place: Chamberlin 5280
Speaker: Chen Li
Abstract: Recent IceCube observations of active galaxies, namely NGC 1068, TXS 0506+056, NGC 4151, CGCG 420-015, NGC 7469 and the Circinus Galaxy, provide compelling evidence for high-energy neutrino production within the innermost regions ($\lesssim 10$ gravitational radii) of supermassive black holes (SMBHs) embedded in the corona region, a dense, X-ray-emitting plasma. In the corona region, protons accelerated near the SMBH interact $0.1 - 1\text{ keV}$ X-rays via $\Delta$-resonance photoproduction and $pp$ interaction to generate neutrinos. At the same time, the X-ray radiation field attenuates the gamma-ray flux produced by neutral pion decay. Finally, we evaluate the hypothesis that such gamma-ray-obscured nuclei constitute the primary population responsible for the diffuse neutrino flux.
Host: Francis Halzen
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