Program: GN-2015B-Q-88

We propose K band imaging with the Gemini Near InfraRed Imager and Spectrometer (NIRI) to observe QSO 1723+59, which is a strong gravitational lens system candidate at z = 1.60. The co-evolution of the supermassive black hole (SMBH) and its central galaxy is the debate of many studies. QSOs allow us to probe the high redshift universe in terms of the SMBH properties. However, previous studies have probed only the low redshift regime (z < 1), or have uncertainties in the QSO-host decomposition. Gravitational lensing is capable of detecting the mass distribution of the lensing object. QSO 1723+59 has two features at ~1" distance from the central QSO. This configuration can be replicated with gravitational lensing theory using a specific lens and source configuration, showing that this is a strong gravitational lens system candidate. Confirming that these two features have the same colors (with existing Hubble Space Telescope F160W imaging data, and K band data from this observation) gives stronger evidence towards the two features originating from the same source, and consequently the QSO acting as a lens. Follow-up spectroscopy will be mandatory to measure the redshifts of the two sources and confirming this system as a gravitational lens system. If this is true, along with other gravitational lens system candidates, it will enable us to determine the evolution of the SMBH-host galaxy relation at high redshifts in more detail.