Optical Continuum and Emission-Line Variability of Seyfert 1 Galaxies
Creators:Peterson, Bradley M.
Hunley, James F.
Pogge, Richard W.
Wagner, R. Mark
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Publisher:American Astronomical Society
Citation:Bradley M. Peterson et al, "Optical Continuum and Emission-Line Variability of Seyfert 1 Galaxies," The Astrophysical Journal 501, no. 1 (1998), doi:10.1086/305813
We present the light curves obtained during an 8 yr program of optical spectroscopic monitoring of nine Seyfert 1 galaxies: 3C 120, Akn 120, Mrk 79, Mrk 110, Mrk 335, Mrk 509, Mrk 590, Mrk 704, and Mrk 817. All objects show significant variability in both the continuum and emission-line fluxes. We use cross-correlation analysis to derive the sizes of the broad Hβ-emitting regions based on emission-line time delays, or lags. We successfully measure time delays for eight of the nine sources and find values ranging from about 2 weeks to a little over 2 months. Combining the measured lags and widths of the variable parts of the emission lines allows us to make virial mass estimates for the active nucleus in each galaxy. The virial masses are in the range 10^7-10^8 Msun.
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