The Awakening Beast in the Seyfert 1 Galaxy KUG 1141+371 I

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 latest Swift observation in 2019 shows 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 one order of magnitude since 2007. The significant multi-wavelength luminosity change is likely due to a boost of mass accretion rate from approximately 0.6% of the Eddington limit to 3.2%, assuming a black hole mass of $10^8{M}_{\odot }$. In this work, we conduct 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 of disc temperature and a decreasing inner disc radius along with the increasing accretion rate. Finally, we discuss possible connection between KUG 1141+371 and black hole transients in outburst.

18 pages, 14 figures, accepted by MNRAS

References in corpus (19)

• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• A Continuum of H- to He-Rich Tidal Disruption Candidates With a Preference for E+A Galaxies
• Paper II: Calibration of the Swift ultraviolet/optical telescope
• Investigating the nature of narrow-line Seyfert 1 galaxies with high-energy spectral complexity
• X-Ray and Optical Microlensing in the Lensed Quasar PG 1115+080
• High Density Reflection Spectroscopy: II. the Density of the Inner Black Hole Accretion Disc in AGN
• A New Catalogue of Type 1 AGN and its Implication on the AGN Unified Model
• High Density Reflection Spectroscopy I. A case study of GX~339-4
• Ultraviolet and X-ray variability of active galactic nuclei with Swift
• IC 3599 did it again: A second outburst of the X-ray transient Seyfert 1.9 Galaxy
• Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes
• Super-Eddington QSO RX J0439.6-5311. II. Multi-wavelength Constraints on the Global Structure of the Accretion Flow
• Polarization of the changing-look quasar J1011+5442
• XMMSL2 J144605.0+685735 : a slow tidal disruption event
• Modeling accretion disk emission with generalized temperature profile and its effect on AGN spectral energy distribution
• Unveiling the physics behind the spectral variations of "changing-look" quasars with optical polarimetry
• A NuSTAR View of GRS 1716$-$249 in the Hard and Intermediate States
• Blueshifted absorption lines from X-ray reflection in IRAS 13224-3809
• Tracing the AGN/X-ray Binary Analogy with Light Curves of Individual Changing-Look AGN

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• The Detection of a Compact Radio Feature in a Seyfert Galaxy After an Accretion Rate Change