Markarian 590 Shows State Transition Linking Active Galactic Nuclei to X-ray Binaries
A decade of Swift satellite observations captured Markarian 590, a changing-look active galactic nucleus (AGN), undergoing a clear state transition in its accretion behavior. The transition follows a V-shaped pattern tied to the Eddington ratio, with a critical break point at 0.021±0.008, matching thresholds seen in other changing-look quasars. This finding suggests AGNs and X-ray binaries share similar accretion physics, providing rare real-time evidence of how inner accretion flows restructure themselves.
Researchers used ten years of multi-wavelength observations from NASA's Swift satellite to track Markarian 590 as it underwent a changing-look event—a dramatic shift in its appearance across ultraviolet, optical, and X-ray wavelengths. The X-ray loudness parameter (αox) exhibited a pronounced V-shaped dependence on the Eddington ratio, with a statistically significant break at 0.021±0.008, consistent with thresholds identified in population studies of other changing-look quasars. The data reveal a transition from a faint, hard X-ray dominated state through a flaring phase to a bright, UV/soft X-ray dominated phase, indicating a fundamental restructuring of the inner accretion disk and corona. Independent UV and X-ray tracers confirmed breaks at similar Eddington ratios (~0.004), strengthening the physical interpretation. The overall evolution timescale is shorter than classical viscous predictions but consistent with propagating thermal fronts in the accretion disk, and radio emission declined relative to X-rays as the disk became more dominant.
What different sources said
- arXiv astro-phCenter
The Millimeter/X-ray Relation in Rapidly Accreting Supermassive Black Holes at $z < 0.16$
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