Department of Physics and Astronomy
Kinard G01, Lecture Hall
Thursday, October 24, 4:00 pm
An X-ray search of the most obscured supermassive black holes
Dr. Stefano Marchesi,
PostDoctoral Fellow at the
Italian National Institute for Astrophysics (INAF-OAS)
Abstract: It is now well established that each galaxy hosts at its center a supermassive black hole (SMBH) with mass ranging from millions to billions times the mass of the Sun. About 1% of these SMBHs are accreting matter and, in the process, emitting light across the electromagnetic spectrum: these accreting SMBHs are called active galactic nuclei (AGN). According to theoretical models, a large fraction of AGN are expected to be heavily obscured by gas and dust surrounding the accreting SMBH: however, as of today, only a minority of the detected AGN are heavily obscured. This discrepancy between data and models is one of the current open challenges for astrophysicists and needs to be solved to get a complete understanding of the AGN population.
In my talk, I will present the results of an ongoing multi-observatory X-ray campaign to find and characterize heavily obscured AGN: X-rays observations are, in fact, one of the most efficient way to discover AGN that would have been missed by observations with optical telescopes. In the last part of the talk, I will also briefly discuss how planned future facilities will further enhance our knowledge on these fascinating and elusive sources.
BIO: Dr. Stefano Marchesi is a PostDoctoral Fellow at the Italian National Institute for Astrophysics (INAF-OAS) in Bologna, Italy. His research focuses on accreting supermassive black holes in the center of galaxies, and particularly on the most obscured among these sources.
He first obtained his bachelor and master degree in Astrophysics at the University of Bologna, Italy, and then obtained his PhD in Astronomy in 2015 again at the University of Bologna. During his PhD years, he was a visiting graduate student at Dartmouth College (Hanover, NH, USA), the Yale Center for Astronomy and Astrophyisics (New Haven, CT, USA) and at the Center for Astrophysics | Harvard & Smithsonian (Cambridge, MA, USA). After graduating, he has been a PostDoctoral Fellow at Clemson University (SC, USA), from 2016 until 2019.
Refreshments will be served afterwards in the PandA Café.
Thursday, October 24 at 4:00pm to 5:00pm
Kinard Laboratory of Physics, G01
140 Delta Epsilon Ct., Clemson, SC 29634, USA