The lick AGN monitoring project 2011: Fe II reverberation from the outer broad-line region

Journal Article · Sat Jun 01 04:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/769/2/128· OSTI ID:22342059

Barth, Aaron J.; Cooper, Michael C. ^[1]; Pancoast, Anna; Treu, Tommaso ^[2]; Bennert, Vardha N. ^[3]; Brewer, Brendon J. ^[4]; Canalizo, Gabriela ^[5]; Filippenko, Alexei V.; Li, Weidong; Cenko, S. Bradley; Clubb, Kelsey I. ^[6]; Gates, Elinor L. ^[7]; Greene, Jenny E. ^[8]; Malkan, Matthew A. ^[9]; Sand, David J. ^[10]; Stern, Daniel; Assef, Roberto J. ^[11]; Woo, Jong-Hak ^[12]; Bae, Hyun-Jin ^[13]; Buehler, Tabitha ^[14] ; others, and

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1. Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697-4575 (United States)
2. Department of Physics, University of California, Santa Barbara, CA 93106 (United States)
3. Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States)
4. Department of Statistics, The University of Auckland, Private Bag 92019, Auckland 1142 (New Zealand)
5. Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)
6. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
7. Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States)
8. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
9. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States)
10. Texas Tech University, Physics Department, Box 41051, Lubbock, TX 79409-1051 (United States)
11. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Boulevard, Pasadena, CA 91109 (United States)
12. Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)
13. Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of)
14. Department of Physics and Astronomy, N283 ESC, Brigham Young University, Provo, UT 84602-4360 (United States)

The prominent broad Fe II emission blends in the spectra of active galactic nuclei have been shown to vary in response to continuum variations, but past attempts to measure the reverberation lag time of the optical Fe II lines have met with only limited success. Here we report the detection of Fe II reverberation in two Seyfert 1 galaxies, NGC 4593 and Mrk 1511, based on data from a program carried out at Lick Observatory in Spring 2011. Light curves for emission lines including Hβ and Fe II were measured by applying a fitting routine to decompose the spectra into several continuum and emission-line components, and we use cross-correlation techniques to determine the reverberation lags of the emission lines relative to V-band light curves. In both cases, the measured lag (τ{sub cen}) of Fe II is longer than that of Hβ, although the inferred lags are somewhat sensitive to the choice of Fe II template used in the fit. For spectral decompositions done using the Fe II template of Véron-Cetty et al., we find τ{sub cen}(Fe II)/τ{sub cen}(Hβ) = 1.9 ± 0.6 in NGC 4593 and 1.5 ± 0.3 in Mrk 1511. The detection of highly correlated variations between Fe II and continuum emission demonstrates that the Fe II emission in these galaxies originates in photoionized gas, located predominantly in the outer portion of the broad-line region.

• OSTI ID: 22342059
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 769; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CORRELATIONS
DECOMPOSITION
DETECTION
EMISSION
GALAXIES
GALAXY NUCLEI
MONITORING
PHOTOIONIZATION
SPECTRA
VARIATIONS
VISIBLE RADIATION