New horizon-scale images of the Galactic Center black hole Sagittarius A* (Sgr A*) recently published by the Event Horizon Telescope (EHT) allow for new strong-field tests of the Kerr metric in a previously unexplored regime. I will discuss the recent EHT observations of Sgr A* with a particular focus on how these new results can be used to test fundamental physics.
The idea that the Planck length can act as a regulator of UV divergences has inspired various approaches to quantum gravity, but a possibly much larger width for the ground state emerges in the (non-perturbative) quantisation of the Oppenheimer-Snyder model of dust collapse that naturally recovers Bekenstein’s area law.
It is well known that a classical charged scalar field on Reissner-Nordström spacetime undergoes superradiant scattering. By quantising the field, via canonical quantisation, we investigate the subtleties that superradiant scattering presents in the quantisation of the field.
Resonances are ubiquitous in nature. In this talk, I will focus on resonances due to the interaction of two black holes orbiting a central massive black hole. Such tidal resonances will generically occur for Extreme Mass Ratio Inspirals (EMRIs), if nearby compact objects exist.
The XV Black Holes Workshop took place at ISCTE in Lisbon, with a record number of participants and communications (group photo attached). The next edition will take place in Porto, at the Faculty of Engineering, in the 19-20 December 2023.
Merry Xmas and happy holidays from our team. Photo from the group Xmas lunch on 16 December 2022, with some collaborators and our wonderful secretary Cristina Grosso.
The last five sessions of the Gr@v group seminars are now on YouTube in our dedicated channel https://www.youtube.com/@Gravchannel. These include the talks from Guilherme Raposo (University of Aveiro), Roberto Emparan (ICREA and Univeristy of Barcelona), Daniela Doneva (University of Tubingen), Andrew Coates (Koc University) and Renate Loll (Radboud University).
The Portuguese Science Foundation (FCT) announced the 6th edition of the individual call to scientific employment stimulus, open from April 4th to May 3rd 2023, for researchers with a Ph.D. and including four different seniority levels. Applications require the support of a host research unit. Researchers wishing to join our group should contact the group coordinator (C. Herdeiro).
Our group coordinated the "Numerical Relativity and High Energy Physics" IRSES network (2012-2015). Here is a list of the global network meetings organized:
