Broad-Line Reverberation in the Kepler-Field Seyfert Galaxy Zw 220-015

Author Info

Aaron J. Barth, University of California - Irvine
My L. Nguyen, University of California - Irvine
Matthew A. Malkan, University of California - Los Angeles
Alexei V. Filippenko, University of California - Berkeley
Weidong Li, University of California - Berkeley
Varoujan Gorjian, Jet Propulsion Laboratory
Michael D. Joner, Brigham Young University - Utah
Vardha N. Bennert, University of California - Santa BarbaraFollow
Janos Botyanski, Lawrence Berkeley National Laboratory
S. Bradley Cenko, University of California - Berkeley
Michael Childress, Lawrence Berkeley National Laboratory
Jieun Choi, University of California - Berkeley
Julia M. Comerford, University of Texas at Austin
Antonino Cucciara, Lawrence Berkeley National Laboratory
Robert da Silva, University of California - Santa Cruz
Gaspard Duchêne, University of California - Berkeley
Michele Fumagalli, University of California - Santa Cruz
Mohan Ganeshalingam, University of California - Berkeley
Elinor L. Gates, Lick Observatory
Brian F. Gerke, Kavli Institute for Particle Astrophysics and Cosmology
Christopher V. Griffith, The Pennsylvania State University
Chelsea Harris, University of California - Santa Barbara
Eric G. Hintz, Brigham Young University - Utah
Eric Hsiao, Lawrence Berkeley National Laboratory
Michael T. Kandrashoff, University of California - Berkeley
William C. Keel, University of Alabama - Tuscaloosa
David Kirkman, University of California - San Diego
Io K.W. Kleiser, University of California - Berkeley
C. David Laney, Brigham Young University - Utah
Jeffrey Lee, University of California - San Diego
Liliana Lopez, University of California - San Diego
Thomas B. Lowe, Lick Observatory
J. Ward Moody, Brigham Young University - Utah
Alexzandir Morton, University of California - Berkeley
A. M. Nierenberg, University of California - Santa Barbara
Peter Nugent, University of California - Berkeley
Anna Pancoast, University of California - Santa Barbara
Jacob Rex, University of California - Berkeley
R. Michael Rich, University of California - Los Angeles
Jeffrey M. Silverman, University of California - Berkeley
Graeme H. Smith, University of California - Santa Cruz
Alessandro Sonnenfeld, University of California - Santa Barbara
Nao Suzuki, Lawrence Berkeley National Laboratory
David Tytler, University of California - San Diego
Jonelle L. Walsh, University of California - Irvine
Jong-Hak Woo, Seoul National University
Yizhe Yang, University of California - Berkeley
Carl Zeisse, University of California - San Diego

Recommended Citation

Published in The Astrophysical Journal, Volume 732, Issue 2, May 10, 2011.

NOTE: At the time of publication, the author Vardha Bennert was not yet affiliated with Cal Poly.

The definitive version is available at https://doi.org/10.1088/0004-637X/732/2/121.

Abstract

The Seyfert 1 galaxy Zw 229-015 is among the brightest active galaxies being monitored by the Kepler mission. In order to determine the black hole mass in Zw 229-015 from Hβ reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad Hβ flux. From cross-correlation measurements, we find that the Hβ light curve has a rest-frame lag of 3.86^+0.69 _–0.90 days with respect to the V-band continuum variations. We also measure reverberation lags for Hα and Hγ and find an upper limit to the Hδ lag. Combining the Hβ lag measurement with a broad Hβ width of σ_line = 1590 ± 47 km s^–1 measured from the rms variability spectrum, we obtain a virial estimate of M _BH = 1.00^+0.19 _–0.24 × 10⁷ M _☉ for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei.

Disciplines

Physics

Copyright

2011 IOP Science.