Significant Size Variation in Quasar PG 2130+099's Broad-line Region Observed

Recent research on the quasar PG 2130+099 has revealed significant changes in the size of its broad-line region (BLR) over a four-year period. The study, titled "Broad-line Region of the Quasar PG 2130+099. II. Doubling the Size Over Four Years?" and authored by Zhu-Heng Yao and 18 other researchers, was accepted for publication in the Astrophysical Journal.

The research builds upon previous reverberation mapping campaigns that reported varying time delays for the BLR, ranging from approximately 10 to 200 days. The latest findings indicate that the time lags of several broad emission lines, including He II, He I, Hβ, and Fe II, have shown continuous variation. Notably, the time lags for the Hβ line have approximately doubled in the last two years of observation.

The study utilized high-cadence monitoring from the Calar Alto Observatory 2.2m optical telescope from 2019 to 2022. The researchers observed that despite a minimal change (around 10%) in the continuum, the substantial variation in time lags has led to significant scatter in the intrinsic relationship between the Hβ radius and the 5100 Å luminosity.

The authors suggest that the observed changes in the BLR size measurements may be influenced by a phenomenon they refer to as 'geometric dilution.' This insight could have implications for understanding the dynamics and geometry of the BLR in quasars, which are critical for comprehending the behavior of supermassive black holes and their surrounding environments.

For further details, the full paper can be accessed at arXiv:2408.17407.