Mrk 382: A Narrow-line Seyfert 1 Galaxy with Recurrent X-Ray State Transitions

Abstract

Abstract We report recurrent X-ray state transitions in the nearby narrow-line Seyfert 1 galaxy Mrk 382 using multiepoch observations from Swift, Chandra, XMM-Newton, and eROSITA, together with archival ultraviolet (UV), optical, and infrared (IR) data. The 0.3–2 keV flux varies by nearly an order of magnitude over ∼15 yr, with multiple transitions between bright and faint states. The X-ray spectrum shows strong state-dependent evolution, changing from a steep high-state continuum (Γ = 2.32 ± 0.04) to a much harder low-state spectrum (Γ = 1.39 ± 0.06), which also exhibits a narrow Fe K α line with an equivalent width of ∼330 eV. Reflection modeling indicates that the low-flux state is strongly reflection dominated, with the reflection fraction increasing from R refl ∼ 4.4 to ∼30, consistent with substantial changes in the inner disk–corona configuration. Photoionized absorption contributes to the spectral complexity, but its relatively modest column density suggests that absorption alone is unlikely to explain the full amplitude of the X-ray transitions. The UV emission shows possible long-term correspondence with the X-ray variability at smaller amplitude, while the optical and mid-IR bands vary more mildly. The spectral and multiwavelength behavior suggests that changes in coronal geometry may be accompanied by changes in its intrinsic energetics. Despite the dramatic X-ray variability, no extreme X-ray-weak state or clear optical spectral-type change is observed. Mrk 382 therefore provides a valuable nearby laboratory for studying the evolution of the disk–corona system and its connection to multiwavelength active galactic nucleus variability.