We report on the results of a 5 year coordinated program of spectroscopic monitoring of the luminous Seyfert 1 galaxy Markarian 509. The Hβ and He II λ4686 emission lines are found to respond to continuum variations with time lags of ~80 and ~60 days, respectively, considerably longer than the emission-line lags measured for other Seyfert galaxies.
展开▼