Flickering of accreting white dwarfs: the remarkable amplitude-flux relation and disc viscosity

Abstract

We analyze optical photometric data of short term variability (flickering) of accreting white dwarfs in cataclysmic variables (KR Aur, MV Lyr, V794 Aql, TT Ari, V425 Cas), recurrent novae (RS Oph and T CrB) and jet-ejecting symbiotic stars (CH Cyg and MWC 560). We find that the amplitude-flux relationship is visible over four orders of magnitude, in the range of fluxes from $10^{29}$ to $10^{33}$ erg s${}^{-1}$ Å${}^{-1}$, as a "statistically perfect" correlation with correlation coefficient 0.96 and p-value $\sim 10^{-28}$. In the above range, the amplitude of variability for any of our 9 objects is proportional to the flux level with (almost) one and the same factor of proportionality for all 9 accreting white dwarfs with $\Delta F=0.36(\pm 0.05)F_{av}$, ${\sigma }_{rms}=0.086(\pm 0.011)F_{av}$, and ${\sigma }_{rms}/\Delta F=0.24\pm 0.02$. Over all, our results indicate that the viscosity in the accretion discs is practically the same for all 9 objects in our sample, in the mass accretion rate range $2\times 10^{-11}-2\times 10^{-7}$ $M_{\odot }$ yr${}^{-1}$.

5 pages, MNRAS 457 L10-L13 (2016)

References in corpus (4)

• The Universal Nature of Accretion-induced Variability: The RMS-Flux Relation in an Accreting White Dwarf
• The rms-flux relation in accreting white dwarfs: another nova-like variable and the first dwarf nova
• Non-Linear Dynamics of Accretion Disks with Stochastic Viscosity
• Optical Flickering of the recurrent nova RS Ophiuchi: amplitude - flux relation

Cited by in corpus (1)

• Active phases and flickering of a symbiotic recurrent nova T CrB