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

By A. Barth, V. Bennert, G. Canalizo, A. Filippenko, E. Gates, Jenny E. Greene, Weidong Li, M. Malkan, A. Pancoast, D. J. Sand and 20 more. 2015

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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 Hβ line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad Hβ line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad Hβ 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 Hβ velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad Hβ 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.

Subfields: Astronomy and Astrophysics, Instrumentation, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/ab6202b800ddfc8c0ed3af3985f4089fd1a75ebb

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Citations in the corpus

Now You See It, Now You Don't: The Disappearing Central Engine of the Quasar J1011+5442 (2015, background): “…disappear completely below the detection limit (Collin-Souffrin et al. 1973; Tohline & Osterbrock 1976; Sanmartim et al. 2014; Denney et al. 2014; Barth et al. 2015) as well as instances where the transition goes in the other direction and the quasar “turns on” (Cohen et al. 1986;…”
The Sloan Digital Sky Survey Reverberation Mapping Project: Hα and Hβ Reverberation Measurements from First-year Spectroscopy and Photometry (2017, methodology): “PrepSpec is similar to recent spectral decomposition approaches (e.g., Barth et al. 2015), but it is optimized to fit all of the spectra of an object simultaneously and includes this flux calibration correction.”
Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. IX. 10 New Observations of Reverberation Mapping and Shortened Hβ Lags (2018, methodology): “…objects by different campaigns (e.g., Peterson et al. 1993, 1998, 2002, 2004; Kaspi et al. 2000, 2007; Bentz et al. 2008, 2009; Denney et al. 2009; Barth et al. 2011, 2013, 2015; Rafter et al. 2011, 2013; Grier et al. 2012, 2017; Du et al. 2014, 2015, 2016b; Wang et al. 2014a; Jiang et al. 2016;…”
A systematic search for close supermassive black hole binaries in the Catalina Real-time Transient Survey (2015, background): “…fraction of an orbital cycle and other astrophysical processes, such as an orbiting hotspot produced by a local instability in the broad line region (BLR) of a galaxy or outflows associated with the accretion disk, may still be responsible for any effect seen (Bogdanović 2015; Barth et al. 2015).”