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

L. Pei, M. M. Fausnaugh, A. J. Barth, B. M. Peterson, M. C. Bentz, G. De Rosa, K. D. Denney, M. R. Goad, C. S. Kochanek, K. T. Korista, G. A. Kriss, R. W. Pogge, V. N. Bennert, M. Brotherton, K. I. Clubb, E. Dalla Bontà, A. V. Filippenko, J. E. Greene, C. J. Grier, M. VestergaardW. Zheng, Scott M. Adams, Thomas G. Beatty, A. Bigley, Jacob E. Brown, Jonathan S. Brown, G. Canalizo, J. M. Comerford, Carl T. Coker, E. M. Corsini, S. Croft, K. V. Croxall, A. J. Deason, Michael Eracleous, O. D. Fox, E. L. Gates, C. B. Henderson, E. Holmbeck, T. W.S. Holoien, J. J. Jensen, C. A. Johnson, P. L. Kelly, S. Kim, A. King, M. W. Lau, Miao Li, Cassandra Lochhaas, Zhiyuan Ma, E. R. Manne-Nicholas, J. C. Mauerhan, M. A. Malkan, R. McGurk, L. Morelli, Ana Mosquera, Dale Mudd, F. Muller Sanchez, M. L. Nguyen, P. Ochner, B. Ou-Yang, A. Pancoast, Matthew T. Penny, A. Pizzella, Radosław Poleski, Jessie Runnoe, B. Scott, Jaderson S. Schimoia, B. J. Shappee, I. Shivvers, Gregory V. Simonian, A. Siviero, Garrett Somers, Daniel J. Stevens, M. A. Strauss, Jamie Tayar, N. Tejos, T. Treu, J. Van Saders, L. Vican, S. Villanueva, H. Yuk, N. L. Zakamska, W. Zhu, M. D. Anderson, P. Arévalo, C. Bazhaw, S. Bisogni, G. A. Borman, M. C. Bottorff, W. N. Brandt, A. A. Breeveld, E. M. Cackett, M. T. Carini, D. M. Crenshaw, A. De Lorenzo-Cáceres, M. Dietrich, R. Edelson, N. V. Efimova, J. Ely, P. A. Evans, G. J. Ferland, K. Flatland, N. Gehrels, S. Geier, J. M. Gelbord, D. Grupe, A. Gupta, P. B. Hall, S. Hicks, D. Horenstein, Keith Horne, T. Hutchison, M. Im, M. D. Joner, J. Jones, J. Kaastra, S. Kaspi, B. C. Kelly, J. A. Kennea, M. Kim, S. C. Kim, S. A. Klimanov, J. C. Lee, D. C. Leonard, P. Lira, F. Macinnis, S. Mathur, I. M. Mchardy, C. Montouri, R. Musso, S. V. Nazarov, H. Netzer, R. P. Norris, J. A. Nousek, D. N. Okhmat, I. Papadakis, J. R. Parks, J. U. Pott, S. E. Rafter, H. W. Rix, D. A. Saylor, K. Schnülle, S. G. Sergeev, M. Siegel, A. Skielboe, M. Spencer, D. Starkey, H. I. Sung, K. G. Teems, C. S. Turner, P. Uttley, C. Villforth, Y. Weiss, J. H. Woo, H. Yan, S. Young, Y. Zu

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

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 +-optical continuum by 4.17+0.36 -0.36 and 0.79+0.35-0.34 days, respectively. The Hβ lag relative to the 1158 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.

Original languageEnglish (US)
Article number131
JournalAstrophysical Journal
Volume837
Issue number2
DOIs
StatePublished - Mar 10 2017

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reverberation
time lag
telescopes
continuums
monitoring
velocity structure
targeting
light curve
analysis
project
Hubble Space Telescope
wings
luminosity
radii

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

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. In: Astrophysical Journal. 2017 ; Vol. 837, No. 2.
@article{161558e7a61a4055967bbaebc47aaf4a,
title = "Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548",
abstract = "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 +-optical continuum by 4.17+0.36 -0.36 and 0.79+0.35-0.34 days, respectively. The Hβ lag relative to the 1158 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.",
author = "L. Pei 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 M. Brotherton and Clubb, {K. I.} and {Dalla Bont{\`a}}, E. and Filippenko, {A. V.} and Greene, {J. E.} and Grier, {C. J.} and M. Vestergaard and W. Zheng and Adams, {Scott M.} and Beatty, {Thomas G.} and A. Bigley and Brown, {Jacob E.} and Brown, {Jonathan S.} and G. Canalizo and Comerford, {J. M.} and Coker, {Carl T.} and Corsini, {E. M.} and S. Croft and Croxall, {K. V.} and Deason, {A. J.} and Michael Eracleous and Fox, {O. D.} and Gates, {E. L.} and Henderson, {C. B.} and E. Holmbeck and Holoien, {T. W.S.} and Jensen, {J. J.} and Johnson, {C. A.} and Kelly, {P. L.} and S. Kim and A. King and Lau, {M. W.} and Miao Li and Cassandra Lochhaas and Zhiyuan Ma and Manne-Nicholas, {E. R.} and Mauerhan, {J. C.} and Malkan, {M. A.} and R. McGurk and L. Morelli and Ana Mosquera and Dale Mudd and Sanchez, {F. Muller} and Nguyen, {M. L.} and P. Ochner and B. Ou-Yang and A. Pancoast and Penny, {Matthew T.} and A. Pizzella and Radosław Poleski and Jessie Runnoe and B. Scott and Schimoia, {Jaderson S.} and Shappee, {B. J.} and I. Shivvers and Simonian, {Gregory V.} and A. Siviero and Garrett Somers and Stevens, {Daniel J.} and Strauss, {M. A.} and Jamie Tayar and N. Tejos and T. Treu and {Van Saders}, J. and L. Vican and S. Villanueva and H. Yuk and Zakamska, {N. L.} and W. Zhu and Anderson, {M. D.} and P. Ar{\'e}valo and C. Bazhaw and S. Bisogni 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-C{\'a}ceres}, A. and M. Dietrich and R. Edelson and Efimova, {N. V.} and J. Ely and Evans, {P. A.} and Ferland, {G. J.} and K. Flatland and N. Gehrels and S. Geier and Gelbord, {J. M.} and D. Grupe and A. Gupta and Hall, {P. B.} and S. Hicks and D. Horenstein and Keith Horne and T. Hutchison and M. Im and Joner, {M. D.} and J. Jones and J. Kaastra and S. Kaspi and Kelly, {B. C.} and Kennea, {J. A.} and M. Kim and Kim, {S. C.} and Klimanov, {S. A.} and Lee, {J. C.} and Leonard, {D. C.} and P. Lira and F. Macinnis and S. Mathur and Mchardy, {I. M.} and C. Montouri and R. Musso and Nazarov, {S. V.} and H. Netzer and Norris, {R. P.} and Nousek, {J. A.} and Okhmat, {D. N.} and I. Papadakis and Parks, {J. R.} and Pott, {J. U.} and Rafter, {S. E.} and Rix, {H. W.} and Saylor, {D. A.} and K. Schn{\"u}lle and Sergeev, {S. G.} and M. Siegel and A. Skielboe and M. Spencer and D. Starkey and Sung, {H. I.} and Teems, {K. G.} and Turner, {C. S.} and P. Uttley and C. Villforth and Y. Weiss and Woo, {J. H.} and H. Yan and S. Young and Y. Zu",
year = "2017",
month = "3",
day = "10",
doi = "10.3847/1538-4357/aa5eb1",
language = "English (US)",
volume = "837",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
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Pei, L, Fausnaugh, MM, Barth, AJ, Peterson, BM, Bentz, MC, De Rosa, G, Denney, KD, Goad, MR, Kochanek, CS, Korista, KT, Kriss, GA, Pogge, RW, Bennert, VN, Brotherton, M, Clubb, KI, Dalla Bontà, E, Filippenko, AV, Greene, JE, Grier, CJ, Vestergaard, M, Zheng, W, Adams, SM, Beatty, TG, Bigley, A, Brown, JE, Brown, JS, Canalizo, G, Comerford, JM, Coker, CT, Corsini, EM, Croft, S, Croxall, KV, Deason, AJ, Eracleous, M, Fox, OD, Gates, EL, Henderson, CB, Holmbeck, E, Holoien, TWS, Jensen, JJ, Johnson, CA, Kelly, PL, Kim, S, King, A, Lau, MW, Li, M, Lochhaas, C, Ma, Z, Manne-Nicholas, ER, Mauerhan, JC, Malkan, MA, McGurk, R, Morelli, L, Mosquera, A, Mudd, D, Sanchez, FM, Nguyen, ML, Ochner, P, Ou-Yang, B, Pancoast, A, Penny, MT, Pizzella, A, Poleski, R, Runnoe, J, Scott, B, Schimoia, JS, Shappee, BJ, Shivvers, I, Simonian, GV, Siviero, A, Somers, G, Stevens, DJ, Strauss, MA, Tayar, J, Tejos, N, Treu, T, Van Saders, J, Vican, L, Villanueva, S, Yuk, H, Zakamska, NL, Zhu, W, Anderson, MD, Arévalo, P, Bazhaw, C, Bisogni, S, Borman, GA, Bottorff, MC, Brandt, WN, Breeveld, AA, Cackett, EM, Carini, MT, Crenshaw, DM, De Lorenzo-Cáceres, A, Dietrich, M, Edelson, R, Efimova, NV, Ely, J, Evans, PA, Ferland, GJ, Flatland, K, Gehrels, N, Geier, S, Gelbord, JM, Grupe, D, Gupta, A, Hall, PB, Hicks, S, Horenstein, D, Horne, K, Hutchison, T, Im, M, Joner, MD, Jones, J, Kaastra, J, Kaspi, S, Kelly, BC, Kennea, JA, Kim, M, Kim, SC, Klimanov, SA, Lee, JC, Leonard, DC, Lira, P, Macinnis, F, Mathur, S, Mchardy, IM, Montouri, C, Musso, R, Nazarov, SV, Netzer, H, Norris, RP, Nousek, JA, Okhmat, DN, Papadakis, I, Parks, JR, Pott, JU, Rafter, SE, Rix, HW, Saylor, DA, Schnülle, K, Sergeev, SG, Siegel, M, Skielboe, A, Spencer, M, Starkey, D, Sung, HI, Teems, KG, Turner, CS, Uttley, P, Villforth, C, Weiss, Y, Woo, JH, Yan, H, Young, S & Zu, Y 2017, 'Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548', Astrophysical Journal, vol. 837, no. 2, 131. https://doi.org/10.3847/1538-4357/aa5eb1

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

In: Astrophysical Journal, Vol. 837, No. 2, 131, 10.03.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548

AU - Pei, L.

AU - Fausnaugh, M. M.

AU - Barth, A. J.

AU - Peterson, B. M.

AU - Bentz, M. C.

AU - De Rosa, G.

AU - Denney, K. D.

AU - Goad, M. R.

AU - Kochanek, C. S.

AU - Korista, K. T.

AU - Kriss, G. A.

AU - Pogge, R. W.

AU - Bennert, V. N.

AU - Brotherton, M.

AU - Clubb, K. I.

AU - Dalla Bontà, E.

AU - Filippenko, A. V.

AU - Greene, J. E.

AU - Grier, C. J.

AU - Vestergaard, M.

AU - Zheng, W.

AU - Adams, Scott M.

AU - Beatty, Thomas G.

AU - Bigley, A.

AU - Brown, Jacob E.

AU - Brown, Jonathan S.

AU - Canalizo, G.

AU - Comerford, J. M.

AU - Coker, Carl T.

AU - Corsini, E. M.

AU - Croft, S.

AU - Croxall, K. V.

AU - Deason, A. J.

AU - Eracleous, Michael

AU - Fox, O. D.

AU - Gates, E. L.

AU - Henderson, C. B.

AU - Holmbeck, E.

AU - Holoien, T. W.S.

AU - Jensen, J. J.

AU - Johnson, C. A.

AU - Kelly, P. L.

AU - Kim, S.

AU - King, A.

AU - Lau, M. W.

AU - Li, Miao

AU - Lochhaas, Cassandra

AU - Ma, Zhiyuan

AU - Manne-Nicholas, E. R.

AU - Mauerhan, J. C.

AU - Malkan, M. A.

AU - McGurk, R.

AU - Morelli, L.

AU - Mosquera, Ana

AU - Mudd, Dale

AU - Sanchez, F. Muller

AU - Nguyen, M. L.

AU - Ochner, P.

AU - Ou-Yang, B.

AU - Pancoast, A.

AU - Penny, Matthew T.

AU - Pizzella, A.

AU - Poleski, Radosław

AU - Runnoe, Jessie

AU - Scott, B.

AU - Schimoia, Jaderson S.

AU - Shappee, B. J.

AU - Shivvers, I.

AU - Simonian, Gregory V.

AU - Siviero, A.

AU - Somers, Garrett

AU - Stevens, Daniel J.

AU - Strauss, M. A.

AU - Tayar, Jamie

AU - Tejos, N.

AU - Treu, T.

AU - Van Saders, J.

AU - Vican, L.

AU - Villanueva, S.

AU - Yuk, H.

AU - Zakamska, N. L.

AU - Zhu, W.

AU - Anderson, M. D.

AU - Arévalo, P.

AU - Bazhaw, C.

AU - Bisogni, S.

AU - Borman, G. A.

AU - Bottorff, M. C.

AU - Brandt, W. N.

AU - Breeveld, A. A.

AU - Cackett, E. M.

AU - Carini, M. T.

AU - Crenshaw, D. M.

AU - De Lorenzo-Cáceres, A.

AU - Dietrich, M.

AU - Edelson, R.

AU - Efimova, N. V.

AU - Ely, J.

AU - Evans, P. A.

AU - Ferland, G. J.

AU - Flatland, K.

AU - Gehrels, N.

AU - Geier, S.

AU - Gelbord, J. M.

AU - Grupe, D.

AU - Gupta, A.

AU - Hall, P. B.

AU - Hicks, S.

AU - Horenstein, D.

AU - Horne, Keith

AU - Hutchison, T.

AU - Im, M.

AU - Joner, M. D.

AU - Jones, J.

AU - Kaastra, J.

AU - Kaspi, S.

AU - Kelly, B. C.

AU - Kennea, J. A.

AU - Kim, M.

AU - Kim, S. C.

AU - Klimanov, S. A.

AU - Lee, J. C.

AU - Leonard, D. C.

AU - Lira, P.

AU - Macinnis, F.

AU - Mathur, S.

AU - Mchardy, I. M.

AU - Montouri, C.

AU - Musso, R.

AU - Nazarov, S. V.

AU - Netzer, H.

AU - Norris, R. P.

AU - Nousek, J. A.

AU - Okhmat, D. N.

AU - Papadakis, I.

AU - Parks, J. R.

AU - Pott, J. U.

AU - Rafter, S. E.

AU - Rix, H. W.

AU - Saylor, D. A.

AU - Schnülle, K.

AU - Sergeev, S. G.

AU - Siegel, M.

AU - Skielboe, A.

AU - Spencer, M.

AU - Starkey, D.

AU - Sung, H. I.

AU - Teems, K. G.

AU - Turner, C. S.

AU - Uttley, P.

AU - Villforth, C.

AU - Weiss, Y.

AU - Woo, J. H.

AU - Yan, H.

AU - Young, S.

AU - Zu, Y.

PY - 2017/3/10

Y1 - 2017/3/10

N2 - 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 +-optical continuum by 4.17+0.36 -0.36 and 0.79+0.35-0.34 days, respectively. The Hβ lag relative to the 1158 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.

AB - 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 +-optical continuum by 4.17+0.36 -0.36 and 0.79+0.35-0.34 days, respectively. The Hβ lag relative to the 1158 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.

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U2 - 10.3847/1538-4357/aa5eb1

DO - 10.3847/1538-4357/aa5eb1

M3 - Article

AN - SCOPUS:85015907676

VL - 837

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 131

ER -