Broad-line Region of the Quasar PG 2130+099 from a Two-year Reverberation Mapping Campaign with High Cadence

As one of the most interesting Seyfert 1 galaxies, PG 2130+099 has been the target of several reverberation mapping (RM) campaigns over the years. However, its measured broad H beta line responses have been inconsistent, with time lags of similar to 200 days, similar to 25 days, and similar to 10 days being reported for different epochs while its optical luminosity changed no more than 40%. To investigate this issue, we conducted a new RM-campaign with homogenous and high cadence (about similar to 3 days) for two years during 2017-2019 to measure the kinematics and structure of the ionized gas. We successfully detected time lags of broad H beta, He II, He I, and Fe II lines with respect to the varying 5100 angstrom continuum, revealing a stratified structure that is likely virialized with Keplerian kinematics in the first year of observations, but an inflow kinematics of the broad-line region from the second year. With a central black hole mass of 0.97(-0.18)(+0.15) x 10(7)M(circle dot), PG 2130+099 has an accretion rate of 10(2.1 +/- 0.5)L(Edd)c(-2), where L-Edd is the Eddington luminosity and c is speed of light, implying that it is a super-Eddington accretor and likely possesses a slim, rather than thin, accretion disk. The fast changes of the ionization structures of the three broad lines remain puzzling.