Résumé / Abstract Seminaire_GReCO

"Massive binary black holes in merging galaxies"

Monica Colpi
Dipt. Fisica, Sezione Astrof., Univ. Milano (Milan, Italie)

Binary black holes occupy a special place in our quest for understanding the evolution of galaxies along cosmic history. If massive black holes grow at the center of (pre-)galactic structures that experience mergers, then close black hole pairs do form as inescapable outcome of galaxy assembly. These black holes may in principle be detected as dual AGN along the course of the collision. If the black holes reach coalescence inside the galaxy remnant, then they become the loudest sources of gravitational waves ever in the universe that the evolving Laser Interferometer Space Antenna (eLISA) aims at detecting out to very high redshifts, during cosmic dawn. Through galaxy mergers Nature provides the pathway for the formation of these exotic binaries, and a number of key questions rise: How do massive black holes pair in a merger? Depending on the structure of the underlying galaxies, do black holes form a close Keplerian binary? If a binary forms, does hardening proceed down to the domain controlled by gravitational wave back reaction? What is the role played by gas and/or stars in braking the black holes, and on which timescale does coalescence occur? Can the black holes accrete during their inspiral and re-orient their spins prior to coalescence? Does this affect the magnitude of the gravitational recoil? After a brief historical recollection of the last parsec problem,I review the progress made in tracing the black hole dynamics in gas-rich mergers with use of numerical simulations and discuss the potential observational impact of these findings.

mercredi 11 juin 2014 - 11:00
Salle des séminaires Évry Schatzman,
Institut d'Astrophysique de Paris

Page web du séminaire / Seminar's webpage