Program: GN-2019B-Q-325

We are embarking on a study of single-cored major merger remnants that will probe the efficiency of evolution and the electromagnetic emission of supermassive black holes (SMBHs) following galaxy merger. SMBHs in binary systems offer a wealth of science in this dawning age of multi-messenger astronomy. However, to enable that science, it is critical to identify clear electromagnetic signatures and better understand the interactions between SMBH pairs and their larger-scale environments. Here, we propose to use the GMOS-N IFU to localize broad-line emission regions in the cores of two spheroidal galaxies, and identify the dynamical centers of these galaxies. By obtaining spatial and spectrally resolved components of the systems at sub-arcsecond resolution, we will be able to identify the positions (offset or central) of any supermassive black holes residing in these merger remnants. These observations will be compared with radio long-baseline observations that track the location and jet age for any radio-emitting active nuclei in the galaxies. Together, these complementary methods of observation will help build a view of the current evolutionary state of the SMBH binaries that should reside in these ongoing mergers.