November 11, 2021 to December 31, 2022
Europe/Zurich timezone

The goal of this (online) seminar is to bring Theoretical Physics closer to experiment and to discuss current topics in high energy theory, cosmology & astrophysics. This intends to renew & continue the tradition of "Proca seminars" (1946-1955) initiated by Alexandru Proca.  The seminar lasts 1h, followed by a questions session of no exact time limit (usually 1/2h). The talks & zoom links are also found here.

Next seminar:

Title:            Observational signatures of hot spots orbiting horizonless objects

Speaker:     Dr.  João Luís Rosa   (Tartu Univ, Estonia)

Date:           Thu 29 Sep 2022, 11:00h  Paris/CEST time,  (12:00h EEST; 18:00h Tokyo time)

Zoom link:   Click here

Abstract: Following a number of advances, electromagnetic observatories have now reached the horizon scale of supermassive black holes. The existence and properties of horizons in our universe is one of the outstanding fundamental issues that can now be addressed. Here we investigate the ability to discriminate between black holes and compact, horizonless objects, focusing on the lensing of hot spots around compact objects. We work in particular with boson and Proca stars as central objects, and show that the absence of a horizon gives rise to a characteristic feature -- photons that plough through the central object and produce an extra image. This feature should be universal for central objects made of matter weakly coupled to the standard model.