THE LICK AGN MONITORING PROJECT 2011: SPECTROSCOPIC CAMPAIGN AND EMISSION-LINE LIGHT CURVES

Abstract

In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad H line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad H line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad H width and luminosity, demonstrating that the broad-line region "breathes" on short timescales of days to weeks in response to continuum variations. We also find that broad H velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad H velocity shifted by 250 km s -1 over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.