We also examined which DRW signals can mimic periodicity and be falsely classified as binary candidates. Through a careful analysis of parameter estimation and Bayesian model selection, we investigated the range of parameter space for which binary systems can be detected. ![]() ![]() Their observed properties are modeled after the Catalina Real-time Transient Survey (CRTS) and expected properties of the upcoming Legacy Survey of Space and Time (LSST) from the Vera C. We simulated a wide variety of realistic DRW and DRW+sine light curves. In this paper, we used Bayesian methods to disentangle periodic SMBHB signals from intrinsic damped random walk (DRW) variability in AGN light curves. However, searches for quasar periodicity in time-domain data are challenging due to the stochastic variability of quasars. At sub-parsec separations, they are practically impossible to resolve and the most promising technique is to search for quasars with periodic variability. Supermassive black hole binaries (SMBHBs) are an inevitable consequence of galaxy mergers. ![]() Our idealized simulations provide an excellent way to uncover the intrinsic limitations in quasar periodicity searches and set the stage for future searches for SMBHBs. We saw similar detection rates both in the CRTS more »Īnd LSST-like simulations, while the false-detection rate depends on the quality of the data and is minimal in LSST. We found that periodic signals are more easily detectable if the period is short or the amplitude of the signal is large compared to the contribution of the DRW noise. In this paper, we used Bayesian methods to disentangle periodic SMBHB signals from intrinsic damped random walk (DRW) variability in active galactic nuclei light curves. At sub-parsec separations, they are practically impossible to resolve, and the most promising technique is to search for quasars with periodic variability. This instrument will peer into a similar slice of the electromagnetic spectrum as Hubble but with an even wider view, making it ideal for tracking down quasars.Abstract Supermassive black hole binaries (SMBHBs) are an inevitable consequence of galaxy mergers. One of its successors, NASA's Nancy Grace Roman Space Telescope, is set to launch in 2027. Hubble is scheduled for decommissioning in 2026, but that doesn’t mean astronomers will have to give up quasar hunting. Scientists believe that studying mergers like these could help us piece together a deeper understanding of how galaxies like our own came to be. Likewise, the galaxies orbiting them have probably become one gigantic elliptical galaxy. Keck Observatory in Hawaii to confirm that the quasars were a binary system, rather than a trick of the light.ĭespite their recent discovery, the double quasars likely no longer exist: In the intervening eons from the light leaving the quasars to the moment it was picked up by Hubble, they have likely collided and merged with one another into a single black hole even more massive than the two that went into it. ![]() But in this case astronomers were able to use ground-based telescopes to double-check Hubble’s work. "We don't see a lot of double quasars at this early time in the universe," Yu-Ching Chen, a researcher at the University of Illinois at Urbana-Champaign and lead author of the study, said in a statement.īecause of the way light bends around a massive gravity source - an effect called gravitational lensing - it can be difficult for scientists to determine whether an apparent double quasar is genuine or an optical illusion. (Image credit: NASA, ESA, Yu-Ching Chen (UIUC), Hsiang-Chih Hwang (IAS), Nadia Zakamska (JHU), Yue Shen (UIUC)) Actual Hubble telescope observations show the two quasars about to collide in the early universe.
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