报告摘要：Recent studies have proposed that the nuclear millimeter continuum emission observed in nearby active galactic nuclei (AGN) could be created by the same population of electrons that gives rise to the X-ray emission that is ubiquitously observed in accreting black holes. In my talk I will present the results of several dedicated high spatial resolution (~60-100 milliarcsecond) 100 GHz ALMA campaigns focussed on nearby radio-quiet AGN. We find an extremely high detection rate (~95\%), which shows that nuclear emission at mm-wavelenghts is nearly ubiquitous in accreting SMBHs. This emission is extremely variable on short timescales, confirming the idea that it comes from a very compact region. Our high-resolution observations show a tight correlation between the nuclear (1-23 pc) 100GHz and the intrinsic X-ray emission. This shows the potential of ALMA continuum observations to detect heavily obscured AGN (up to an optical depth of one at 100GHz, i.e. ~1e27 cm^-2), and to identify binary SMBHs with separations <100 pc, which cannot be probed by current X-ray facilities.
主讲人简介：Claudio Ricci is an Italian astronomer specializing in high-energy astrophysics, focusing on supermassive black holes and active galactic nuclei. He earned his Ph.D. from the Université de Genève, Switzerland, in 2011. Following his doctorate, he held postdoctoral positions at the University of Geneva, Kyoto University, and Pontificia Universidad Católica de Chile. In 2018, he joined Universidad Diego Portales in Santiago, Chile, where he is now Associate professor, and where he leads the High-Energy Research on Obscuration and Emission in Supermassive Black Holes (HEROES) team. He will be moving back to the Université de Genève in June 2025 as a faculty. Ricci co-founded and co-leads the Swift/BAT AGN Spectroscopic Survey (BASS), and is leading the AGN follow up working group in the LSST collaboration. He is a scientific editor for the AAS journals since January 2024.
