Formation of the largest galactic cores through binary scouring and gravitational wave recoil

Massive elliptical galaxies are typically observed to have central cores in their projected radial light profiles. Such long been thought form through `binary scouring' as supermassive black holes (SMBHs), brought mergers, a hard binary and eject stars from the galactic centre. However, most massive cores, like ~3kpc core A2261-BCG, remain challenging explain this way. In paper, we run suite of dry galaxy merger simulations explore three different scenarios for formation galaxies: scouring', `tidal deposition' `gravitational wave (GW) induced recoil'. Using Griffin code, self-consistently model stars, dark matter SMBHs our merging galaxies, following SMBH dynamics binary. We find that can only large surface brightness A2261-BCG with combination major produces small ~1kpc scouring, followed by subsequent GW recoil its acts grow size. show same also bright `knots' region A2261-BCG. Key predictions scenario an offset surrounded compact cluster bound non-divergent density profile. best explained stalled perturbers resulting minor though brightest may represent ejected stellar cloak stars.