Variability In A Low-Mass AGN: Oscillation Or Eruption? by Robbie Webbe et al. on Monday 21 November
Following the discovery of a new class of X-ray variability seen in four
galaxies, dubbed Quasi-Periodic Eruptions (QPEs), we reconsider the variability
seen in the low-mass AGN 2XMM J123103.2+110648 to ascertain whether it should
be considered the fifth QPE host galaxy. We apply the autocorrelation function
to two archival XMM-Newton observations to determine characteristic timescales
for variability of $\sim$ 13.52 ks and $\sim$ 14.35 ks. The modelling of
lightcurves, both folded at these timescales and unfolded, indicates that a
Gaussian model is preferable over a sinusoidal model, with average durations
for the bright phases of 6.17 ks and 7.69 ks. In a broad 0.2-1.0 keV band the
average amplitude of the bright phases was found to be 2.86 and 8.56 times the
quiescent count rate. The pattern of variability seen in 2XMM J123103.2+110648
cannot be definitively declared as a series of Quasi-Periodic Eruptions.
Instead, this suggests there may be a continuum of quasi-periodic variability
ranging from eruptions to oscillations being caused by a single mechanism. This
offers the possibility of finding further sources that continue to bridge the
gap between QPEs and Quasi-Periodic Oscillations. A targeted analysis of 47
observations of 11 other low-mass AGN $(log(M_{BH}) \lesssim 6)$ found no
evidence of QPE or QPO-like behaviour in a sample of other similar mass
objects.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.10176v1
