Dr. Joey Neilsen

"The Many Shadows of Black Holes"

ABSTRACT -- In April of 2019, the Event Horizon Telescope Collaboration reported the groundbreaking detection of the first image of a black hole, the shadow of the supermassive black hole in M87. With this triumph of engineering, observations, data analysis, and theory, we have entered a new era of black hole astrophysics. I will present a high-energy astrophysicist's view of how we got here, the EHT's first results, and what comes next. Looking to the future, I will focus on how coordinated EHT/X-ray observations can help us address lingering open questions about accretion onto black holes, including how they accelerate particles to high energies and, possibly, the physics of variability around our own supermassive black hole, Sagittarius A* (Sgr A*).

SPEAKER -- Joey Neilsen is a black hole astrophysicist and Assistant Professor of Physics at Villanova University. He received undergraduate degrees Kenyon College in Physics and Mathematics; he studied with Julia Lee at Harvard University and received his PhD in 2011. He joined the Villanova faculty after NASA Einstein and Hubble fellowships at Boston University and MIT. Neilsen is an expert in X-ray observations of black holes, and he and his students are frequent users of NICER, built at Goddard and now installed on the International Space Station, as well as NASA's Chandra X-ray Observatory and NuSTAR. These sensitive facilities offer an exciting view into the energetic lives of black holes. Neilsen is also a member of the Event Horizon Telescope's Multiwavelength Working Group, and he and his student Jadyn Anczarski were fortunate enough to be able to contribute their X-ray expertise to the EHT's first detection of the shadow of the supermassive black hole in M87.

Engineering Colloquium home page: https://ecolloq.gsfc.nasa.gov