Monitoring observation of PG0934+013 using The Southern African Large Telescope

  • Park, Dawoo (Dept. of physics and astronomy, Seoul National University) ;
  • Woo, Jong-Hak (Dept. of physics and astronomy, Seoul National University) ;
  • Romero-Colmenero, Encarni (South African Astronomical Observatory) ;
  • Crawford, Steven M. (South African Astronomical Observatory) ;
  • Barth, Aaron J. (Dept. of physics and astronomy, University of California) ;
  • Pei, Liuyi (Dept. of physics and astronomy, University of California)
  • 발행 : 2013.10.08

초록

We performed spectroscopic and photometric monitoring observations of a QSO, PG0934+013 for a reverberation-mapping analysis, using the 9-m Southern African Large Telescope (SALT) for spectroscopy and the 2-m Faulkes Telescope North and the South for photometry. The monitoring campaign was carried out for 5 month between December 2012 to April 2013, providing 20 spectroscopic epochs and ~40 photometric epochs. Based on the obtained spectra, which typically have a signal-to-noise ratio to 30-60, we performed multicomponent decomposition using various components, i.e., power-law continuum, FeII emission complex, and broad and narrow emission lines, to properly measure the Hbeta line flux. After a flux normalization using [O III] 5007 line luminosity, we obtained a rms spectrum from all epochs, which shows clear variability of Hbeta line. We find that Hbeta line flux decreases by ~20% during the monitoring period while the continuum flux obtained from the aperture photometry based on the imaging data, shows similar variability. The current Hbeta light curve shows monotonic decrease and a reliable cross correlation analysis between Hbeta and continuum light is difficult. Nevertheless, we obtained a preliminary lag measurements as ~24 light days.

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