Oral Presentation

The Variability Structure Function of the Highest-Luminosity Quasars on Short Timescales

Author(s): Ji-Jia Tang (NTU)

Presenter: Ji-Jia Tang (NTU)

The stochastic photometric variability of quasars is known to follow a random-walk phenomenology on emission timescales of months to years. Some high-cadence restframe optical monitoring of the past has hinted at a suppression of variability amplitudes on shorter timescales of a few days or weeks, opening the question of what drives the suppression and how it might scale with quasar properties. Here, we study a few thousand of the highest-luminosity quasars in the sky, mostly in the luminosity range of L_bol=[46.4, 47.3] and redshift range of z=[0.7, 2.4]. We use a dataset from the NASA/ATLAS facility with nightly cadence, weather permitting, which has been used before to quantify strong regularity in longer-term restframe-UV variability. As we focus on a careful treatment of short timescales across the sample, we find no evidence of any systematic breaks or suppression in the UV variability structure function at short timescales; instead, the data is consistent with a single-slope random walk across restframe timescales of dt=[10, 250] days.