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Title: Reverberation Mapping of Optical Emission Lines in Five Active Galaxies

Abstract

We present the first results from an optical reverberation mapping campaign executed in 2014 targeting the active galactic nuclei (AGNs) MCG+08-11-011, NGC 2617, NGC 4051, 3C 382, and Mrk 374. Our targets have diverse and interesting observational properties, including a “changing look” AGN and a broad-line radio galaxy. Based on continuum-H β lags, we measure black hole masses for all five targets. We also obtain H γ and He ii λ 4686 lags for all objects except 3C 382. The He ii λ 4686 lags indicate radial stratification of the BLR, and the masses derived from different emission lines are in general agreement. The relative responsivities of these lines are also in qualitative agreement with photoionization models. These spectra have extremely high signal-to-noise ratios (100–300 per pixel) and there are excellent prospects for obtaining velocity-resolved reverberation signatures.

Authors:
; ; ; ; ; ;  [1]; ;  [2];  [3];  [4];  [5];  [6]; ;  [7];  [8];  [9];  [10];  [11];  [12] more »; « less
  1. Department of Astronomy, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States)
  2. Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)
  3. Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States)
  4. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  5. Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
  6. Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States)
  7. Department of Physics and Astronomy, University of Wyoming, 1000 E. University Avenue, Laramie, WY (United States)
  8. Crimean Astrophysical Observatory, P/O Nauchny, Crimea 298409 (Russian Federation)
  9. Las Cumbres Global Telescope Network, 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117 (United States)
  10. Fountainwood Observatory, Department of Physics FJS 149, Southwestern University, 1011 E. University Avenue, Georgetown, TX 78626 (United States)
  11. Department of Physics and Astronomy, University of Missouri, Columbia (United States)
  12. South African Astronomical Observatory, P.O. Box 9, Observatory 7935, Cape Town (South Africa)
Publication Date:
OSTI Identifier:
22663611
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 840; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; EMISSION; GALAXY NUCLEI; MASS; PHOTOIONIZATION; RADIO GALAXIES; SIGNAL-TO-NOISE RATIO; SPECTRA; STRATIFICATION

Citation Formats

Fausnaugh, M. M., Denney, K. D., Peterson, B. M., Kochanek, C. S., Pogge, R. W., Brown, Jonathan S., Coker, C. T., Grier, C. J., Beatty, Thomas G., Bentz, M. C., Rosa, G. De, Adams, S. M., Barth, A. J., Bhattacharjee, A., Brotherton, M. S., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brown, Jacob E., Crawford, S. M., and and others. Reverberation Mapping of Optical Emission Lines in Five Active Galaxies. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA6D52.
Fausnaugh, M. M., Denney, K. D., Peterson, B. M., Kochanek, C. S., Pogge, R. W., Brown, Jonathan S., Coker, C. T., Grier, C. J., Beatty, Thomas G., Bentz, M. C., Rosa, G. De, Adams, S. M., Barth, A. J., Bhattacharjee, A., Brotherton, M. S., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brown, Jacob E., Crawford, S. M., & and others. Reverberation Mapping of Optical Emission Lines in Five Active Galaxies. United States. doi:10.3847/1538-4357/AA6D52.
Fausnaugh, M. M., Denney, K. D., Peterson, B. M., Kochanek, C. S., Pogge, R. W., Brown, Jonathan S., Coker, C. T., Grier, C. J., Beatty, Thomas G., Bentz, M. C., Rosa, G. De, Adams, S. M., Barth, A. J., Bhattacharjee, A., Brotherton, M. S., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brown, Jacob E., Crawford, S. M., and and others. Wed . "Reverberation Mapping of Optical Emission Lines in Five Active Galaxies". United States. doi:10.3847/1538-4357/AA6D52.
@article{osti_22663611,
title = {Reverberation Mapping of Optical Emission Lines in Five Active Galaxies},
author = {Fausnaugh, M. M. and Denney, K. D. and Peterson, B. M. and Kochanek, C. S. and Pogge, R. W. and Brown, Jonathan S. and Coker, C. T. and Grier, C. J. and Beatty, Thomas G. and Bentz, M. C. and Rosa, G. De and Adams, S. M. and Barth, A. J. and Bhattacharjee, A. and Brotherton, M. S. and Borman, G. A. and Boroson, T. A. and Bottorff, M. C. and Brown, Jacob E. and Crawford, S. M. and and others},
abstractNote = {We present the first results from an optical reverberation mapping campaign executed in 2014 targeting the active galactic nuclei (AGNs) MCG+08-11-011, NGC 2617, NGC 4051, 3C 382, and Mrk 374. Our targets have diverse and interesting observational properties, including a “changing look” AGN and a broad-line radio galaxy. Based on continuum-H β lags, we measure black hole masses for all five targets. We also obtain H γ and He ii λ 4686 lags for all objects except 3C 382. The He ii λ 4686 lags indicate radial stratification of the BLR, and the masses derived from different emission lines are in general agreement. The relative responsivities of these lines are also in qualitative agreement with photoionization models. These spectra have extremely high signal-to-noise ratios (100–300 per pixel) and there are excellent prospects for obtaining velocity-resolved reverberation signatures.},
doi = {10.3847/1538-4357/AA6D52},
journal = {Astrophysical Journal},
number = 2,
volume = 840,
place = {United States},
year = {Wed May 10 00:00:00 EDT 2017},
month = {Wed May 10 00:00:00 EDT 2017}
}
  • We present the first results from an optical reverberation mapping campaign executed in 2014 targeting the active galactic nuclei (AGNs) MCG+08-11-011, NGC 2617, NGC 4051, 3C 382, and Mrk 374. Our targets have diverse and interesting observational properties, including a “changing look” AGN and a broad-line radio galaxy. Based on continuum-Hβ lags, we measure black hole masses for all five targets. We also obtain Hγ and He II λ4686 lags for all objects except 3C 382. The He II λ4686 lags indicate radial stratification of the BLR, and the masses derived from different emission lines are in general agreement. Themore » relative responsivities of these lines are also in qualitative agreement with photoionization models. Finally, these spectra have extremely high signal-to-noise ratios (100–300 per pixel) and there are excellent prospects for obtaining velocity-resolved reverberation signatures.« less
  • A tight relation between the size of the broad-line region (BLR) and optical luminosity has been established in about 50 active galactic nuclei studied through reverberation mapping of the broad Hβ emission line. The R {sub BLR}-L relation arises from simple photoionization considerations. Using a general relativistic model of an optically thick, geometrically thin accretion disk, we show that the ionizing luminosity jointly depends on black hole mass, accretion rate, and spin. The non-monotonic relation between the ionizing and optical luminosity gives rise to a complicated relation between the BLR size and the optical luminosity. We show that the reverberationmore » lag of Hβ to the varying continuum depends very sensitively on black hole spin. For retrograde spins, the disk is so cold that there is a deficit of ionizing photons in the BLR, resulting in shrinkage of the hydrogen ionization front with increasing optical luminosity, and hence shortened Hβ lags. This effect is specially striking for luminous quasars undergoing retrograde accretion, manifesting in strong deviations from the canonical R {sub BLR}-L relation. This could lead to a method to estimate black hole spins of quasars and to study their cosmic evolution. At the same time, the small scatter of the observed R {sub BLR}-L relation for the current sample of reverberation-mapped active galaxies implies that the majority of these sources have rapidly spinning black holes.« less
  • We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program. The data were collected at several observatories over a 140 day span beginning in 2010 August and ending in 2011 January. We obtained high sampling-rate light curves for Mrk 335, Mrk 1501, 3C 120, Mrk 6, and PG 2130+099, from which we have measured the time lag between variations in the 5100 A continuum and the H{beta} broad emission line. We then used these measurements to calculate the mass of the supermassivemore » black hole at the center of each of these galaxies. Our new measurements substantially improve previous measurements of M{sub BH} and the size of the broad line-emitting region for four sources and add a measurement for one new object. Our new measurements are consistent with photoionization physics regulating the location of the broad line region in active galactic nuclei.« less
  • Variations in the strengths of the central photoionization source in a quasar or Seyfert galaxy will generate variations in the strengths and profiles of the emission lines. These ''reverberations'' in the emission lines will lag behind the continuum variations due to light travel time effects. A procedure is described for analyzing a time series of measurements of both the continuum and the lines. This procedure permits direct verification of the assumed causal connection of the lines to the continuum. We demonstrate that if the emission line region has a high degree of symmetry, then it is possible to invert themore » time-dependent line profiles and obtain the phase space distribution of the emission-line gas: i.e., its emissivity and the moments of its velocity distributions as functions of position. The cases of spherical and disk symmetry are considered in detail; the case of a straight jet, which may be relevent to correlated optical and radio variations, is discussed briefly. Explicit calculations of expected line variations have been carried out for several simple models. We suggest that with recently developed instrumentation it should now be possible to apply this technique to Seyfert galaxies. Long term, highly accurate observations will be required for the application to quasars.« less
  • We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3 m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range {approx}10{sup 6}-10{sup 7} M{sub sun} and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in themore » broad H{beta} emission, which we have previously reported. We present here the light curves for the H{alpha}, H{gamma}, He II {lambda}4686, and He I {lambda}5876 emission lines and the time lags for the emission-line responses relative to changes in the continuum flux. Combining each emission-line time lag with the measured width of the line in the variable part of the spectrum, we determine a virial mass of the central supermassive black hole from several independent emission lines. We find that the masses are generally consistent within the uncertainties. The time-lag response as a function of velocity across the Balmer line profiles is examined for six of the AGNs. We find similar responses across all three Balmer lines for Arp 151, which shows a strongly asymmetric profile, and for SBS 1116+583A and NGC 6814, which show a symmetric response about zero velocity. For the other three AGNs, the data quality is somewhat lower and the velocity-resolved time-lag response is less clear. Finally, we compare several trends seen in the data set against the predictions from photoionization calculations as presented by Korista and Goad. We confirm several of their predictions, including an increase in responsivity and a decrease in the mean time lag as the excitation and ionization level for the species increases. Specifically, we find the time lags of the optical recombination lines to have weighted mean ratios of {tau}(H{alpha}):{tau}(H{beta}):{tau}(H{gamma}):{tau}(He I):{tau}(He II) = 1.54:1.00:0.61:0.36:0.25. Further confirmation of photoionization predictions for broad-line gas behavior will require additional monitoring programs for these AGNs while they are in different luminosity states.« less