Spectral and timing analysis of the frequent flares experienced by AT2019wey

Abstract

In this paper, we compare the timing and spectral properties for those frequent flares observed in AT2019wey from 2020 August to 2023 March. We conducted a comparative analysis of the evolution of timing properties, specifically the continuum fractional rms, broadband noise characteristic frequency, and spectral parameters, in relation to the hardness ratio and count rates for all 10 flares. Based on the timing and spectral properties, we have identified four flares entering high soft state and six flares not. For all flares, the continuum fractional rms decreases with increasing count rates whereas characteristic frequency of broadband noise behaves in the opposite way. Meanwhile, the disc temperature $T_{\mathrm{in}}$ and powerlaw index Γ consistently increases throughout all flares. During the 10 flares, the luminosity of accretion disc does not follow the canonical $L\sim T^4$ relation which implicates a moving disc inner radius.