Joint Astrophysical Colloquium
The Event Horizon Telescope journey from the Earth to the heart of the Milky Way
Mariafelicia de Laurentis / Rocco Lico (Università di Napoli Federico II / IAA-CSIC)
Thursday 15/12/2022 @ 11:30, Sala IV piano Battiferro + Remote
In this talk we will review the science process, imaging analysis and theoretical interpretation that led to the publication of the first Event Horizon Telescope (EHT) observations of the supermassive black hole, known as Sagittarius A* (Sgr A*), lurking at the center of the Milky Way. The observations were conducted in 2017 at a wavelength of 1.3 mm, using a world-wide interferometric array of eight telescopes. This allowed us to resolve the compact emission region and to reveal a morphology dominated by a bright and thick ring with a central dark depression, the so-called black hole shadow, with a diameter of ~52?as. The whole imaging analysis was cross-validated by a variety of imaging and modeling methods. As demonstrated by a comprehensive suite of numerical simulations, the SgrA* EHT images are consistent with the expected appearance of a ~4.3 million solar masses Kerr black hole. Our models disfavour those scenarios where the black hole is viewed at high inclination (>50deg), as well as those with retrograde accretion disks. Moreover, by comparing the SgrA* and M87* results, we were able to test the predictions of General Relativity over three orders of magnitude in central mass.