Investigating the Variable Continuum Lags in PG 2130+099

Abstract

Broadband photometric reverberation mapping (RM) provides a measure of the size of the continuum-emitting region in active galactic nuclei (AGN). Previous monitoring campaigns of PG 2130+099 disagree as to whether the continuum emitting region size is consistent with that predicted for a standard optically thick geometrically thin accretion disk. We present $\sim$6 months of observations from several robotic telescopes, providing the highest cadence and widest wavelength coverage photometric RM study of PG 2130+099 to date. Our results indicate that inferred size of the continuum-emitting region in PG 2130+099, like many recently observed AGN, is larger than the simplest predictions for an irradiated geometrically thin, optically thick accretion disk. We also perform a flux-flux analysis, finding a variable spectrum broadly consistent with a disk, and a constant component with enhanced $\text{i}$-band emission, potentially due to H$\hat{I}\pm$. We find some evidence of increasing lag with luminosity, but previous lag measurements are too uncertain to be definitive.

16 Pages (14 Main + 2 Appendix), 8 Figures, 4 Tables. Accepted for publication in ApJ