SEMINAR OF THE DEPARTMENT OF ASTRONOMY
Do We Really Know What’s at the Center of Our Galaxy?
a talk by Parthraj Bambhaniya (IAG-USP) - In-Person
Abstract:
Recent observations by the Event Horizon Telescope (EHT) and GRAVITY collaborations of Sagittarius A* (Sgr A*) at the heart of our galaxy have garnered significant interest, prompting investigations of its properties. In particular, through studies of its shadow imaging, accretion dynamics, and the orbits of S-stars. The classical Oppenheimer-Snyder-Dutt (OSD) model predicts black hole formation from gravitational collapse, while Penrose's cosmic censorship conjecture (CCC) extends this idea and suggests that the singularity must remain hidden within an event horizon. However, Penrose’s CCC remains unproven and more realistic gravitational collapse models challenge these assumptions, raising the possibility of naked singularities or supermassive compact objects. In this talk, we discuss the generalized shadow formation conditions by supermassive compact objects and how precise astrometric data from the GRAVITY and UCLA Galactic Center groups provide insights into the spacetime geometry of Sgr A*. Finally, we discuss observational tests that could distinguish a black hole from alternative supermassive compact objects, improving our understanding of the core of the Milky Way.
Short-Bio:
Currently, Parthraj Bambhaniya is a FAPESP postdoctoral fellow at the Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG), University of São Paulo (USP), Brazil. Prior to this current role, he was a postdoctoral fellow at Ahmedabad University, India, working on theoretical foundation of black holes and spacetime singularities. He has completed his PhD in 2023 from Charusat University, India, focusing on "Theory of Black Holes and Beyond."
Google Meet: https://meet.google.com/pcw-gmem-jyi
Link da transmissão: https://www.youtube.com/c/AstronomiaIAGUSP/live