“Seeing the Unseeable – Imaging Black Holes with the Event Horizon Telescope” with Angelo Ricarte (Institute for Theory and Computation (ITC) Fellow Center for Astrophysics Harvard & Smithsonian, USA)

Most massive galaxies are believed to host supermassive black holes at their centers, where they play important roles in heating gas and suppressing star formation. Using a large network of radio telescopes around the world, the Event Horizon Telescope (EHT) collaboration produced the first resolved image of a supermassive black hole, located in the elliptical galaxy Messier 87. The EHT combines distant telescopes using the very-long-baseline interferometry (VLBI) technique, achieving equivalent angular resolution to a telescope the size of the Earth. Earlier this year, this image was upgraded to include linear polarization, the oscillation direction of incoming electric fields, which has provided new and substantial information for constraining models of the black hole and its accretion flow. All models that pass both total intensity and linear polarization constraints feature dynamically important magnetic fields. These first EHT images usher in a new era of gravity, accretion, feedback, and plasma physics studies in the direct vicinity of a black hole. Continued development of the EHT will enable novel studies of the image as a function of time as well as observing wavelength.

Angelo Ricarte is a Filipino-American astrophysicist from California. He completed his undergraduate education at the University of California at Berkeley. Afterwards, he completed his Ph.D in the Yale astronomy department with Priya Natarajan. Angelo is currently a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics as well as the Black Hole Initiative, working with Ramesh Narayan. He is a theoretical astrophysicist working on understanding the formation and evolution of supermassive black holes using computer simulations, both on event horizon and cosmological scales. On cosmological scales, he studies the co-evolution of supermassive black holes and their host galaxies. On event horizon scales, he focuses on the theoretical interpretation of polarized black hole images, especially the recent polarized image of the black hole in elliptical galaxy Messier 87. He works actively on the Event Horizon Telescope, the world-wide interferometer which has provided the first image of a supermassive black hole!

Webinar was recorded on October 7, 2021