Reverberation Mapping of PG 0934+013 with the Southern African Large Telescope

Abstract

We present the variability and time-lag measurements of PG 0934+013 based on a photometric and spectroscopic monitoring campaign over a two year period. We obtained 46 epochs of data from the spectroscopic campaign, which was carried out using the Southern African Large Telescope with ∼1 week cadence over two sets of four month-long observing period, while we obtained 80 epochs of B -band imaging data using a few 1 m class telescopes. Due to the seven month gap between the two observing periods, we separately measured the time lags of broad emission lines, including H β , by comparing the emission line light curve with the B -band continuum light curve using the cross-correlation function techniques. We determined the H β lag, days in the observed frame based on Year 2 data, while the time lag from Year 1 data was not reliably determined. Using the rms spectrum of Year 2 data, we measured the H β line dispersion  = 668 ± 44 km s −1  after correcting for the spectral resolution. Adopting a virial factor f = 4.47 from Woo et al. (2015), we determined the black hole mass M BH M ⊙,  based on the H β time lag and velocity.