Περίληψη :
Periodic signatures in time-domain observations of quasars have been used to search for binary supermassive black holes (SMBHs). These searches, across existing time-domain surveys, have produced several hundred photometric candidates with no full confirmation of detection. The general stochastic variability of quasars can masquerade as a false-positive periodic signal, especially when monitoring cadence and baseline are limited. In this work, we predict the detectability of binary SMBHs in the upcoming Rubin Observatory Legacy Survey of Space and Time (LSST). We apply detection methods ranging from computationally inexpensive curve fits to deep learning algorithms to millions of simulated LSST Deep Drilling Field light curves of both single, isolated quasars and binary SMBHs. We find that luminous, single quasars are more likely to be classified as false-positive binary detections, and that binary signals are easily obscured by the large variability amplitudes of low-luminosity quasars. Increasing light curve baselines from the 10-year LSST lifetime to 20 years can reduce the high false positive rates. This work represents an important way forward for understanding the true and false-positive rates for binary candidates to be identified by Rubin. The eventual discovery of binary SMBHs, to be aided by Rubin, will further our understanding of galaxy-SMBH co-evolution, black hole inspiral, accretion environments, galaxy merger rates, electromagnetic counterparts for gravitational wave background sources, and more.
