Abstract

KUG 1141 +371 is a Seyfert 1 galaxy that shows a simultaneous flux increase in the optical and UV bands in the past decade. For instance, the Swift observations in 2019 show that the UVW2 flux of the AGN in KUG 1141 +371 has increased by over one order of magnitude since 2009. Meanwhile, the soft X-ray flux of KUG 1141 +371 also shows a steady increase by almost one order of magnitude from 2007 to 2019. The significant multi-wavelength luminosity change is likely due to a boost in mass accretion rate from approximately 0.6% of the Eddington limit to 3.2%, assuming a black hole mass of 100 million solar masses. I will present a detailed multi-epoch X-ray spectral analysis focusing on the variability of the X-ray continuum emission and the puzzling soft excess emission. In addition, our SED models also suggest a simultaneous increase in disc temperature and a decreasing inner disc radius along with the increasing accretion rate. Simultaneous ground-based optical observations show significant changes in the permitted line profiles and optical continuum. Finally, I will discuss the possible connection between KUG 1141 +371 and black hole transients in outburst.