Orateur
Description
Despite the re-birth of multi-messenger astronomy, no unambiguous electromagnetic (EM) counterpart to binary black hole (BBH) pre-/post-merger has been reported. Indeed, stellar-mass BBHs are expected to be gas-poor ; however, this should not be the case of supermassive BBHs, whose GWs will be detectable with LISA (2035+). Detecting the EM pre-merger counterpart would allow for optimal follow-up. Nonetheless, the accretion properties onto BBHs and the related EM signatures are not firmly identified because, until recently, very few numerical codes were able to model accretion and emission around BBHs in General Relativity (GR).
The picture has evolved in the last few years. In this talk, I will present results obtained with e-NOVAs ("extended Numerical Observatory for Violent Accreting systems"; Varniere+18), a GR-magnetohydrodynamical (Casse+17) + GR ray-tracing code (Vincent+11) recently extended to dynamical spacetimes and now incorporating analytical BBH spacetimes. I will study the circumbinary disk evolution and its EM observables, emphasizing the various plausible sources of variability and the contribution from relativistic effects: those could be the smoking-guns of BBHs. Finally, I will mention on-going developments of e-NOVAs allowing us to address the robustness of other, complementary EM signatures associated with the BH's individual disks.
