2003/01/13 by Philip Uttley, Phil Uttley, Rick Edelson +6 · 5 citations
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/373887
published as Astrophys.J. 584 (2003) L53-L56 · Accepted for publication in ApJ Letters
arxiv created 2003/01/13 · openalex publication_date 2003/02/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We combine the long-term optical light curve of the Seyfert 1 galaxy NGC 5548 with the X-ray light curve measured by the Rossi X-Ray Timing Explorer over 6 years, to determine the relationship between the optical and X-ray continua. The X-ray light curve is strongly correlated with the optical light curve on long (~1 yr) timescales. The amplitude of the long-term optical variability in NGC 5548 is larger than that of the X-ray variability (after accounting for the host galaxy contribution), implying that X-ray reprocessing is not the main source of the optical/X-ray correlation. The correlated X-ray and optical variations in NGC 5548 may be caused by instabilities in the inner part of the accretion flow, where both the X-ray and the optical emission regions may be located.