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

Abstract

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 Hβ, by comparing the emission line light curve with the B-band continuum light curve using the cross-correlation function techniques. We determined the Hβ 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 Hβ 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 Hβ time lag and velocity.