Giovedì 17 novembre alle ore 15:00, la Dr. Paola Severgnini dell’INAF OA Brera, Milano, terrà il web-seminar dal titolo: Dual and binary supermassive black holes: from galaxy mergers to Gravitational Waves.
Dual (kpc scale separation) and binary (pc scale separation) supermassive black hole (SMBH) systems are the inevitable consequence of the hierarchical growth of galaxies, and they should be commonplace. The dynamical evolution of these systems within the merged galaxies, and their interaction with the host encode crucial information about the assembly of galaxy bulges and SMBHs. Even more compelling, binary SMBHs are loud emitters of gravitational waves in the low-frequency ranges.
Although these dual and binary SMBHs are a natural outcome of galaxy mergers, directly observing them during different merger stages is still a challenging task not only because of the stringent resolution requirements, but also because of the intrinsic difficulty in identifying SMBHs. From the observational point of view the quest of dual SMBHs in late state of galaxy merger is in a pioneering age while a direct detection of binary SMBHs is still a completely open challenge.
In this talk, I will briefly review the electromagnetic signatures expected for dual and binary active SMBH (AGN). I will present recent results obtained by our group through the multi-wavelength data analysis of a sample of optically selected dual AGN hosted in early-merger galaxies. I will discuss new efficient methods to unveil dual AGN in late-merger galaxies and, finally, I will also present two of the most promising active SMBH binary candidates (sub-pc scale separation) uncovered through observations in the X-ray band.