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Title: Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548

Abstract

Here, we present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The Hβ and He II λ4686 broad emission-line light curves lag that of the 5100 Å optical continuum by $${4.17}_{-0.36}^{+0.36}\,\mathrm{days}$$ and $${0.79}_{-0.34}^{+0.35}\,\mathrm{days}$$, respectively. The Hβ lag relative to the 1158 Å ultraviolet continuum light curve measured by the Hubble Space Telescope is ~50% longer than that measured against the optical continuum, and the lag difference is consistent with the observed lag between the optical and ultraviolet continua. This suggests that the characteristic radius of the broad-line region is ~50% larger than the value inferred from optical data alone. We also measured velocity-resolved emission-line lags for Hβ and found a complex velocity-lag structure with shorter lags in the line wings, indicative of a broad-line region dominated by Keplerian motion. The responses of both the Hβ and He ii emission lines to the driving continuum changed significantly halfway through the campaign, a phenomenon also observed for C iv, Lyα, He II(+O III]), and Si Iv(+O Iv]) during the same monitoring period. Finally, given the optical luminosity of NGC 5548 during our campaign, the measured Hβ lag is a factor of five shorter than the expected value implied by the R BLR–L AGN relation based on the past behavior of NGC 5548.

Authors:
 [1];  [2]; ORCiD logo [3];  [4]; ORCiD logo [5];  [6];  [7]; ORCiD logo [8]; ORCiD logo [7];  [9];  [10]; ORCiD logo [7]; ORCiD logo [11];  [12];  [13];  [14]; ORCiD logo [13];  [15]; ORCiD logo [16]; ORCiD logo [17] more »;  [13];  [18]; ORCiD logo [19];  [13];  [20]; ORCiD logo [2];  [21];  [22]; ORCiD logo [2];  [14]; ORCiD logo [13]; ORCiD logo [23];  [24];  [25]; ORCiD logo [13];  [26]; ORCiD logo [27];  [28]; ORCiD logo [23];  [29]; ORCiD logo [30]; ORCiD logo [31];  [7];  [32]; ORCiD logo [24]; ORCiD logo [33];  [2]; ORCiD logo [20];  [5];  [13]; ORCiD logo [28]; ORCiD logo [34];  [14];  [35];  [2];  [22];  [12];  [14];  [5]; ORCiD logo [36]; ORCiD logo [2]; ORCiD logo [14];  [2];  [37];  [21]; ORCiD logo [38]; ORCiD logo [39]; ORCiD logo [13];  [2];  [40];  [41];  [2]; ORCiD logo [15]; ORCiD logo [2];  [42]; ORCiD logo [43];  [39]; ORCiD logo [28]; ORCiD logo [2];  [13]; ORCiD logo [44]; ORCiD logo [2];  [5]; ORCiD logo [45];  [5];  [46];  [47];  [48]; ORCiD logo [49]; ORCiD logo [50]; ORCiD logo [51];  [52]; ORCiD logo [5];  [53];  [54];  [55];  [56]; ORCiD logo [6];  [8]; ORCiD logo [57];  [58];  [59];  [60];  [61]; ORCiD logo [62];  [63];  [64];  [65];  [5];  [53];  [48]; ORCiD logo [66];  [67];  [5];  [68];  [69];  [70]; ORCiD logo [71];  [72];  [72];  [57];  [72];  [58];  [73];  [48]; ORCiD logo [7];  [74];  [75];  [48];  [47]; ORCiD logo [76];  [5];  [71];  [47];  [77];  [5]; ORCiD logo [78];  [79]; ORCiD logo [78]; ORCiD logo [5];  [78];  [47];  [80];  [29]; ORCiD logo [67];  [53];  [72];  [5];  [5];  [81]; ORCiD logo [82];  [83];  [66];  [20];  [55];  [84] « less
  1. Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy; Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Astronomy
  2. The Ohio State Univ., Columbus, OH (United States). Dept of Astronomy
  3. Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy
  4. The Ohio State Univ., Columbus, OH (United States). Dept of Astronomy; The Ohio State Univ., Columbus, OH (United States). Center for Cosmology and AstroParticle Physics; Space Telescope Science Inst., Baltimore, MD (United States)
  5. Georgia State Univ., Atlanta, GA (United States). Dept. of Physics and Astronomy
  6. Space Telescope Science Inst., Baltimore, MD (United States)
  7. The Ohio State Univ., Columbus, OH (United States). Dept of Astronomy; The Ohio State Univ., Columbus, OH (United States). Center for Cosmology and AstroParticle Physics
  8. Univ. of Leicester (United Kingdom). Dept. of Physics and Astronomy
  9. Western Michigan Univ., Kalamazoo MI (United States). Dept. of Physics
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  11. California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States). Dept. of Physics
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  13. Univ. of California, Berkeley, CA (United States). Dept. of Astronomy
  14. Univ. degli Studi di Padova (Italy). Dipartimento di Fisica e Astronomia; Istituto Nazionale di Astrofisica (INAF), Padova (Italy). Osservatorio Astronomico di Padova
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  20. Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
  21. Univ. of California, Riverside, CA (United States). Dept. of Astronomy
  22. Univ. of Colorado, Boulder, CO (United States). Dept. of Astrophysical and Planetary Sciences
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  24. Univ. of California, Santa Cruz, CA (United States). Dept. of Astronomy and Astrophysics
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  26. Lick Observatory, Mt. Hamilton, CA (United States)
  27. The Ohio State Univ., Columbus, OH (United States). Dept of Astronomy; California Inst. of Technology (CalTech), Pasadena, CA (United States). Jet Propulsion Lab.
  28. Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy
  29. Univ. of Copenhagen (Denmark). The Niels Bohr Inst., Dark Cosmology Centre
  30. Univ. of California, Santa Cruz, CA (United States). Santa Cruz Inst. for Particle Physics and Dept. of Physics
  31. Stanford Univ., CA (United States). Dept. of Physics; Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States)
  32. Univ. of Melbourne (Australia). School of Physics
  33. Columbia Univ., New York, NY (United States). Dept. of Astronomy
  34. Univ. of California, Santa Cruz, CA (United States). Dept. of Astronomy and Astrophysics; Max Planck Inst. for Astronomie, Heidelberg (Germany)
  35. The Ohio State Univ., Columbus, OH (United States). Dept of Astronomy; United States Naval Academy, Annapolis, MD (United States). Dept. of Physics
  36. Univ. of California, Santa Barbara, CA (United States). Dept. of Physics; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
  37. Pennsylvania State Univ., University Park, PA (United States). Eberly College of Science, Dept of Astronomy and Astrophysics; Pennsylvania State Univ., University Park, PA (United States). Inst. for Gravitation and the Cosmos; Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Astronomy
  38. The Ohio State Univ., Columbus, OH (United States). Dept of Astronomy; Univ. Federal do Rio do Sul, Porto Alegre (Brazil). Inst. de Fisica
  39. Carnegie Observatories, Pasadena, CA (United States)
  40. Univ. degli Studi di Padova (Italy). Dipartimento di Fisica e Astronomia
  41. The Ohio State Univ., Columbus, OH (United States). Dept of Astronomy; Vanderbilt Univ., Nashville, TN (United States). Dept. of Physics and Astronomy
  42. Millennium Inst. of Astrophysics, Santiago (Chile); Pontifical Catholic Univ. of Chile, Santiago (Chile)
  43. Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy; Univ. of California, Santa Barbara, CA (United States). Dept. of Physics
  44. Johns Hopkins Univ., Baltimore, MD (United States). Department of Physics and Astronomy
  45. Univ. de Valparaiso (Chile). Inst. de Fisica y Astronomia
  46. The Ohio State Univ., Columbus, OH (United States). Dept of Astronomy; Osservatorio Astrofisico di Arcetri, Firenze (Italy)
  47. Crimean Astrophysical Observatory, Crimea (Russia)
  48. Southwestern Univ., Georgetown, TX (United States). Fountainwood Observatory, Dept. of Physics
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  50. Univ. College London (UCL), Surrey (United Kingdom). Mullard Space Science Lab. (MSSL)
  51. Wayne State Univ., Detroit, MI (United States). Dept. of Physics and Astronomy
  52. Western Kentucky Univ., Bowling Green, KY (United States)
  53. Univ. of St. Andrews, Scotland (United Kingdom). School of Physics and Astronomy
  54. Ohio Univ., Athens, OH (United States). Dept. of Physics and Astronomy; Worcester State Univ., MA (United States)
  55. Univ. of Maryland, College Park, MD (United States). Dept. of Astronomy
  56. Pulkovo Observatory, St. Petersburg (Russia)
  57. Univ. of Kentucky, Lexington, KY (United States). Dept. of Physics and Astronomy
  58. San Diego State Univ., CA (United States). Dept. of Astronomy
  59. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States). Astrophysics Science Division
  60. Inst. de Astrofisica de Canarias, Tenerife (Spain); Univ. of La Laguna, Tenerife (Spain). Dept. de Astrofisica; Gran Telescopio Canarias (GRANTECAN), Tenerife (Spain)
  61. Spectral Sciences Inc., Burlington, MA (United States); Eureka Scientific Inc., Oakland, CA (United States)
  62. Morehead State Univ., KY (United States). Space Science Center
  63. The Ohio State Univ., Columbus, OH (United States). Dept. of Astronomy
  64. York Univ., Toronto, ON (Canada). Dept. of Physics and Astronomy
  65. Western Kentucky Univ., Bowling Green, KY (United States). Dept. of Physics and Astronomy
  66. Seoul National Univ. (Korea, Republic of). Dept. of Physics & Astronomy
  67. Brigham Young Univ., Provo, UT (United States). Dept. of Physics and Astronomy
  68. SRON Netherlands Inst. for Space Research, Utrecht (Netherlands); Univ. of Utrecht (Netherlands). Dept. of Physics and Astronomy; Leiden Univ. (Netherlands). Leiden Observatory
  69. Tel Aviv Univ. (Israel). School of Physics and Astronomy; Technion-Israel Inst. of Tech., Haifa (Israel). Dept. of Physics
  70. Univ. of California, Santa Barbara, CA (United States). Dept. of Physics
  71. Pennsylvania State Univ., University Park, PA (United States). Eberly College of Science, Dept of Astronomy and Astrophysics
  72. Korea Astronomy and Space Science Inst. (Korea)
  73. Univ. de Chile, Santiago (Chile). Dept. de Astronomia
  74. Univ. of Southampton (United Kingdom)
  75. Univ. dell' Insubria, Como (Italy). Dept. of Applied Science and Technology (DISAT)
  76. Tel Aviv Univ. (Israel). School of Physics and Astronomy
  77. Univ. of Crete (Greece). Inst. of Theoretical and Computational Physics, Dept. of Physics; Inst. of Electronic Structure and Laser (IESL), Crete (Greece). Foundation for Research and Technology (FORTH)
  78. Max Planck Inst. for Astronomie, Heidelberg (Germany)
  79. Technion-Israel Inst. of Tech., Haifa (Israel). Dept. of Physics; Univ. of Haifa (Israel). Dept. of Physics
  80. Las Cumbres Observatory Global Telescope Network, Goleta, CA (United States)
  81. Univ. of Amsterdam (Netherlands). Anton Pannekoek Astronomical Inst.
  82. Univ. of Bath (United Kingdom)
  83. Technion-Israel Inst. of Tech., Haifa (Israel). Dept. of Physics
  84. The Ohio State Univ., Columbus, OH (United States). Center for Cosmology and AstroParticle Physics; Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Physics
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE; National Science Foundation (NSF); National Aeronautic and Space Administration (NASA); UK Science and Technology Facilities Council; National Research Foundation of Korea (NRFK); Netherlands Organization for Scientific Research (NWO)
OSTI Identifier:
1352630
Grant/Contract Number:
AC02-76SF00515; FG02-97ER25308; NAS5-26555; AST-1412693; AST-1008882; AST-1253702; AST-1211916; AST-1515876; AST-1312296; AST-1302093; ST/M001296/1; AST-0618209; DFF 4002-00275
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 837; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS

Citation Formats

Pei, L., Fausnaugh, M. M., Barth, A. J., Peterson, B. M., Bentz, M. C., De Rosa, G., Denney, K. D., Goad, M. R., Kochanek, C. S., Korista, K. T., Kriss, G. A., Pogge, R. W., Bennert, V. N., Brotherton, M., Clubb, K. I., Dalla Bontà, E., Filippenko, A. V., Greene, J. E., Grier, C. J., Vestergaard, M., Zheng, W., Adams, Scott M., Beatty, Thomas G., Bigley, A., Brown, Jacob E., Brown, Jonathan S., Canalizo, G., Comerford, J. M., Coker, Carl T., Corsini, E. M., Croft, S., Croxall, K. V., Deason, A. J., Eracleous, Michael, Fox, O. D., Gates, E. L., Henderson, C. B., Holmbeck, E., Holoien, T. W. -S., Jensen, J. J., Johnson, C. A., Kelly, P. L., Kim, S., King, A., Lau, M. W., Li, Miao, Lochhaas, Cassandra, Ma, Zhiyuan, Manne-Nicholas, E. R., Mauerhan, J. C., Malkan, M. A., McGurk, R., Morelli, L., Mosquera, Ana, Mudd, Dale, Sanchez, F. Muller, Nguyen, M. L., Ochner, P., Ou-Yang, B., Pancoast, A., Penny, Matthew T., Pizzella, A., Poleski, Radosław, Runnoe, Jessie, Scott, B., Schimoia, Jaderson S., Shappee, B. J., Shivvers, I., Simonian, Gregory V., Siviero, A., Somers, Garrett, Stevens, Daniel J., Strauss, M. A., Tayar, Jamie, Tejos, N., Treu, T., Van Saders, J., Vican, L., Villanueva, S., Yuk, H., Zakamska, N. L., Zhu, W., Anderson, M. D., Arévalo, P., Bazhaw, C., Bisogni, S., Borman, G. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Cackett, E. M., Carini, M. T., Crenshaw, D. M., De Lorenzo-Cáceres, A., Dietrich, M., Edelson, R., Efimova, N. V., Ely, J., Evans, P. A., Ferland, G. J., Flatland, K., Gehrels, N., Geier, S., Gelbord, J. M., Grupe, D., Gupta, A., Hall, P. B., Hicks, S., Horenstein, D., Horne, Keith, Hutchison, T., Im, M., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, M., Kim, S. C., Klimanov, S. A., Lee, J. C., Leonard, D. C., Lira, P., MacInnis, F., Mathur, S., McHardy, I. M., Montouri, C., Musso, R., Nazarov, S. V., Netzer, H., Norris, R. P., Nousek, J. A., Okhmat, D. N., Papadakis, I., Parks, J. R., Pott, J. -U., Rafter, S. E., Rix, H. -W., Saylor, D. A., Schnülle, K., Sergeev, S. G., Siegel, M., Skielboe, A., Spencer, M., Starkey, D., Sung, H. -I., Teems, K. G., Turner, C. S., Uttley, P., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., and Zu, Y.. Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548. United States: N. p., 2017. Web. doi:10.3847/1538-4357/aa5eb1.
Pei, L., Fausnaugh, M. M., Barth, A. J., Peterson, B. M., Bentz, M. C., De Rosa, G., Denney, K. D., Goad, M. R., Kochanek, C. S., Korista, K. T., Kriss, G. A., Pogge, R. W., Bennert, V. N., Brotherton, M., Clubb, K. I., Dalla Bontà, E., Filippenko, A. V., Greene, J. E., Grier, C. J., Vestergaard, M., Zheng, W., Adams, Scott M., Beatty, Thomas G., Bigley, A., Brown, Jacob E., Brown, Jonathan S., Canalizo, G., Comerford, J. M., Coker, Carl T., Corsini, E. M., Croft, S., Croxall, K. V., Deason, A. J., Eracleous, Michael, Fox, O. D., Gates, E. L., Henderson, C. B., Holmbeck, E., Holoien, T. W. -S., Jensen, J. J., Johnson, C. A., Kelly, P. L., Kim, S., King, A., Lau, M. W., Li, Miao, Lochhaas, Cassandra, Ma, Zhiyuan, Manne-Nicholas, E. R., Mauerhan, J. C., Malkan, M. A., McGurk, R., Morelli, L., Mosquera, Ana, Mudd, Dale, Sanchez, F. Muller, Nguyen, M. L., Ochner, P., Ou-Yang, B., Pancoast, A., Penny, Matthew T., Pizzella, A., Poleski, Radosław, Runnoe, Jessie, Scott, B., Schimoia, Jaderson S., Shappee, B. J., Shivvers, I., Simonian, Gregory V., Siviero, A., Somers, Garrett, Stevens, Daniel J., Strauss, M. A., Tayar, Jamie, Tejos, N., Treu, T., Van Saders, J., Vican, L., Villanueva, S., Yuk, H., Zakamska, N. L., Zhu, W., Anderson, M. D., Arévalo, P., Bazhaw, C., Bisogni, S., Borman, G. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Cackett, E. M., Carini, M. T., Crenshaw, D. M., De Lorenzo-Cáceres, A., Dietrich, M., Edelson, R., Efimova, N. V., Ely, J., Evans, P. A., Ferland, G. J., Flatland, K., Gehrels, N., Geier, S., Gelbord, J. M., Grupe, D., Gupta, A., Hall, P. B., Hicks, S., Horenstein, D., Horne, Keith, Hutchison, T., Im, M., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, M., Kim, S. C., Klimanov, S. A., Lee, J. C., Leonard, D. C., Lira, P., MacInnis, F., Mathur, S., McHardy, I. M., Montouri, C., Musso, R., Nazarov, S. V., Netzer, H., Norris, R. P., Nousek, J. A., Okhmat, D. N., Papadakis, I., Parks, J. R., Pott, J. -U., Rafter, S. E., Rix, H. -W., Saylor, D. A., Schnülle, K., Sergeev, S. G., Siegel, M., Skielboe, A., Spencer, M., Starkey, D., Sung, H. -I., Teems, K. G., Turner, C. S., Uttley, P., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., & Zu, Y.. Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548. United States. doi:10.3847/1538-4357/aa5eb1.
Pei, L., Fausnaugh, M. M., Barth, A. J., Peterson, B. M., Bentz, M. C., De Rosa, G., Denney, K. D., Goad, M. R., Kochanek, C. S., Korista, K. T., Kriss, G. A., Pogge, R. W., Bennert, V. N., Brotherton, M., Clubb, K. I., Dalla Bontà, E., Filippenko, A. V., Greene, J. E., Grier, C. J., Vestergaard, M., Zheng, W., Adams, Scott M., Beatty, Thomas G., Bigley, A., Brown, Jacob E., Brown, Jonathan S., Canalizo, G., Comerford, J. M., Coker, Carl T., Corsini, E. M., Croft, S., Croxall, K. V., Deason, A. J., Eracleous, Michael, Fox, O. D., Gates, E. L., Henderson, C. B., Holmbeck, E., Holoien, T. W. -S., Jensen, J. J., Johnson, C. A., Kelly, P. L., Kim, S., King, A., Lau, M. W., Li, Miao, Lochhaas, Cassandra, Ma, Zhiyuan, Manne-Nicholas, E. R., Mauerhan, J. C., Malkan, M. A., McGurk, R., Morelli, L., Mosquera, Ana, Mudd, Dale, Sanchez, F. Muller, Nguyen, M. L., Ochner, P., Ou-Yang, B., Pancoast, A., Penny, Matthew T., Pizzella, A., Poleski, Radosław, Runnoe, Jessie, Scott, B., Schimoia, Jaderson S., Shappee, B. J., Shivvers, I., Simonian, Gregory V., Siviero, A., Somers, Garrett, Stevens, Daniel J., Strauss, M. A., Tayar, Jamie, Tejos, N., Treu, T., Van Saders, J., Vican, L., Villanueva, S., Yuk, H., Zakamska, N. L., Zhu, W., Anderson, M. D., Arévalo, P., Bazhaw, C., Bisogni, S., Borman, G. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Cackett, E. M., Carini, M. T., Crenshaw, D. M., De Lorenzo-Cáceres, A., Dietrich, M., Edelson, R., Efimova, N. V., Ely, J., Evans, P. A., Ferland, G. J., Flatland, K., Gehrels, N., Geier, S., Gelbord, J. M., Grupe, D., Gupta, A., Hall, P. B., Hicks, S., Horenstein, D., Horne, Keith, Hutchison, T., Im, M., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, M., Kim, S. C., Klimanov, S. A., Lee, J. C., Leonard, D. C., Lira, P., MacInnis, F., Mathur, S., McHardy, I. M., Montouri, C., Musso, R., Nazarov, S. V., Netzer, H., Norris, R. P., Nousek, J. A., Okhmat, D. N., Papadakis, I., Parks, J. R., Pott, J. -U., Rafter, S. E., Rix, H. -W., Saylor, D. A., Schnülle, K., Sergeev, S. G., Siegel, M., Skielboe, A., Spencer, M., Starkey, D., Sung, H. -I., Teems, K. G., Turner, C. S., Uttley, P., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., and Zu, Y.. Fri . "Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548". United States. doi:10.3847/1538-4357/aa5eb1. https://www.osti.gov/servlets/purl/1352630.
@article{osti_1352630,
title = {Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548},
author = {Pei, L. and Fausnaugh, M. M. and Barth, A. J. and Peterson, B. M. and Bentz, M. C. and De Rosa, G. and Denney, K. D. and Goad, M. R. and Kochanek, C. S. and Korista, K. T. and Kriss, G. A. and Pogge, R. W. and Bennert, V. N. and Brotherton, M. and Clubb, K. I. and Dalla Bontà, E. and Filippenko, A. V. and Greene, J. E. and Grier, C. J. and Vestergaard, M. and Zheng, W. and Adams, Scott M. and Beatty, Thomas G. and Bigley, A. and Brown, Jacob E. and Brown, Jonathan S. and Canalizo, G. and Comerford, J. M. and Coker, Carl T. and Corsini, E. M. and Croft, S. and Croxall, K. V. and Deason, A. J. and Eracleous, Michael and Fox, O. D. and Gates, E. L. and Henderson, C. B. and Holmbeck, E. and Holoien, T. W. -S. and Jensen, J. J. and Johnson, C. A. and Kelly, P. L. and Kim, S. and King, A. and Lau, M. W. and Li, Miao and Lochhaas, Cassandra and Ma, Zhiyuan and Manne-Nicholas, E. R. and Mauerhan, J. C. and Malkan, M. A. and McGurk, R. and Morelli, L. and Mosquera, Ana and Mudd, Dale and Sanchez, F. Muller and Nguyen, M. L. and Ochner, P. and Ou-Yang, B. and Pancoast, A. and Penny, Matthew T. and Pizzella, A. and Poleski, Radosław and Runnoe, Jessie and Scott, B. and Schimoia, Jaderson S. and Shappee, B. J. and Shivvers, I. and Simonian, Gregory V. and Siviero, A. and Somers, Garrett and Stevens, Daniel J. and Strauss, M. A. and Tayar, Jamie and Tejos, N. and Treu, T. and Van Saders, J. and Vican, L. and Villanueva, S. and Yuk, H. and Zakamska, N. L. and Zhu, W. and Anderson, M. D. and Arévalo, P. and Bazhaw, C. and Bisogni, S. and Borman, G. A. and Bottorff, M. C. and Brandt, W. N. and Breeveld, A. A. and Cackett, E. M. and Carini, M. T. and Crenshaw, D. M. and De Lorenzo-Cáceres, A. and Dietrich, M. and Edelson, R. and Efimova, N. V. and Ely, J. and Evans, P. A. and Ferland, G. J. and Flatland, K. and Gehrels, N. and Geier, S. and Gelbord, J. M. and Grupe, D. and Gupta, A. and Hall, P. B. and Hicks, S. and Horenstein, D. and Horne, Keith and Hutchison, T. and Im, M. and Joner, M. D. and Jones, J. and Kaastra, J. and Kaspi, S. and Kelly, B. C. and Kennea, J. A. and Kim, M. and Kim, S. C. and Klimanov, S. A. and Lee, J. C. and Leonard, D. C. and Lira, P. and MacInnis, F. and Mathur, S. and McHardy, I. M. and Montouri, C. and Musso, R. and Nazarov, S. V. and Netzer, H. and Norris, R. P. and Nousek, J. A. and Okhmat, D. N. and Papadakis, I. and Parks, J. R. and Pott, J. -U. and Rafter, S. E. and Rix, H. -W. and Saylor, D. A. and Schnülle, K. and Sergeev, S. G. and Siegel, M. and Skielboe, A. and Spencer, M. and Starkey, D. and Sung, H. -I. and Teems, K. G. and Turner, C. S. and Uttley, P. and Villforth, C. and Weiss, Y. and Woo, J. -H. and Yan, H. and Young, S. and Zu, Y.},
abstractNote = {Here, we present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The Hβ and He II λ4686 broad emission-line light curves lag that of the 5100 Å optical continuum by ${4.17}_{-0.36}^{+0.36}\,\mathrm{days}$ and ${0.79}_{-0.34}^{+0.35}\,\mathrm{days}$, respectively. The Hβ lag relative to the 1158 Å ultraviolet continuum light curve measured by the Hubble Space Telescope is ~50% longer than that measured against the optical continuum, and the lag difference is consistent with the observed lag between the optical and ultraviolet continua. This suggests that the characteristic radius of the broad-line region is ~50% larger than the value inferred from optical data alone. We also measured velocity-resolved emission-line lags for Hβ and found a complex velocity-lag structure with shorter lags in the line wings, indicative of a broad-line region dominated by Keplerian motion. The responses of both the Hβ and He ii emission lines to the driving continuum changed significantly halfway through the campaign, a phenomenon also observed for C iv, Lyα, He II(+O III]), and Si Iv(+O Iv]) during the same monitoring period. Finally, given the optical luminosity of NGC 5548 during our campaign, the measured Hβ lag is a factor of five shorter than the expected value implied by the R BLR–L AGN relation based on the past behavior of NGC 5548.},
doi = {10.3847/1538-4357/aa5eb1},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 837,
place = {United States},
year = {Fri Mar 10 00:00:00 EST 2017},
month = {Fri Mar 10 00:00:00 EST 2017}
}

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  • During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide themore » Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with the Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all three observations: the UV emission-line flux decrease, the soft-excess increase, and the emission-line anomaly.« less
  • During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide themore » Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with the Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. In conclusion, this model simultaneously explains all three observations: the UV emission-line flux decrease, the soft-excess increase, and the emission-line anomaly.« less
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  • Reverberation-mapping-based scaling relations are often used to estimate the masses of black holes from single-epoch spectra of active galactic nuclei (AGNs). While the radius–luminosity relation that is the basis of these scaling relations is determined using reverberation mapping of the Hβ line in nearby AGNs, the scaling relations are often extended to use other broad emission lines, such as Mg ii, in order to get black hole masses at higher redshifts when Hβ is redshifted out of the optical waveband. However, there is no radius–luminosity relation determined directly from Mg ii. Here, we present an attempt to perform reverberation mappingmore » using Mg ii in the well-studied nearby Seyfert 1 NGC 5548. We used Swift to obtain UV grism spectra of NGC 5548 once every two days from 2013 April to September. Concurrent photometric UV monitoring with Swift provides a well determined continuum light curve that shows strong variability. The Mg ii emission line, however, is not strongly correlated with the continuum variability, and there is no significant lag between the two. We discuss these results in the context of using Mg ii scaling relations to estimate high-redshift black hole masses.« less
  • Emission-line and UV continuum observations of the type I Seyfert galaxy NGC 5548 were carried out for a period of 8 months with the IUE satellite. It was found that both the continuum shape and the line ratios of NGC 5548, while being not unusual for type I Seyfert galaxies, are strongly variable. The UV continuum flux and broad emission line fluxed went through three large maxima and three deep minima; the ratio of miximum to minimum flux was about 4.5 for the continuum at 1350 A. The N V and the He II emission lines exhibited maximum-to-minimum flux ratiosmore » as high as those of the continuum; other ionization lines (Ly-alpha, C IV, and C III) exhibited smaller amplitude fluctuations, with the smallest being recorded for the Mg II line (about 1.3). It was found that, except for Mg II, the emission-line variations correlated extremely well with those of the 1350-A continuum. 51 refs.« less
  • A one-dimensional echo map of the broad H-beta emission-line region in the Seyfert 1 galaxy NGC 5548 is reconstructed by using a maximum entropy technique to model the variable optical continuum and integrated H-beta emission-line fluxes observed during the 1989-1990 monitoring campaign as reported by Peterson et al. (1991). The echo map has a strong peak at a time delay of 20 lt-days which has an unresolved full width of 20 days at half-maximum. The H-beta response at time delay zero is less than one-third of that at 20 days, implying a deficit of H-beta-emitting gas near the line ofmore » sight to the continuum source. This rules out spherically symmetric and edge-on disk geometries for isotropically emitting H-beta clouds. 7 refs.« less