Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum

G. A. Kriss; G. De Rosa; J. Ely; B. M. Peterson; J. Kaastra; M. Mehdipour; G. J. Ferland; M. Dehghanian; S. Mathur; R. Edelson; K. T. Korista; N. Arav; A. J. Barth; M. C. Bentz; W. N. Brandt; D. M. Crenshaw; Elena Dalla Bontà; K. D. Denney; C. Done; M. Eracleous; M. M. Fausnaugh; E. Gardner; M. R. Goad; C. J. Grier; Keith Horne; C. S. Kochanek; I. M. McHardy; H. Netzer; A. Pancoast; L. Pei; R. W. Pogge; D. Proga; C. Silva; N. Tejos; M. Vestergaard; S. M. Adams; M. D. Anderson; P. Arévalo; T. G. Beatty; E. Behar; V. N. Bennert; S. Bianchi; A. Bigley; S. Bisogni; R. Boissay-Malaquin; G. A. Borman; M. C. Bottorff; A. A. Breeveld; M. Brotherton; J. E. Brown; J. S. Brown; E. M. Cackett; G. Canalizo; M. Cappi; M. T. Carini; K. I. Clubb; J. M. Comerford; C. T. Coker; E. M. Corsini; E. Costantini; S. Croft; K. V. Croxall; A. J. Deason; A. De Lorenzo-Cáceres; B. De Marco; M. Dietrich; L. Di Gesu; J. Ebrero; P. A. Evans; A. V. Filippenko; K. Flatland; E. L. Gates; N. Gehrels; S. Geier; J. M. Gelbord; L. Gonzalez; V. Gorjian; D. Grupe; A. Gupta; P. B. Hall; C. B. Henderson; S. Hicks; E. Holmbeck; T. W.S. Holoien; T. A. Hutchison; M. Im; J. J. Jensen; C. A. Johnson; M. D. Joner; S. Kaspi; B. C. Kelly; P. L. Kelly; J. A. Kennea; M. Kim; S. C. Kim; S. Y. Kim; A. King; S. A. Klimanov; Y. Krongold; M. W. Lau; J. C. Lee; D. C. Leonard; Miao Li; P. Lira; C. Lochhaas; Zhiyuan Ma; F. Macinnis; M. A. Malkan; E. R. Manne-Nicholas; G. Matt; J. C. Mauerhan; R. McGurk; C. Montuori; L. Morelli; A. Mosquera; D. Mudd; F. Müller-Sánchez; S. V. Nazarov; R. P. Norris; J. A. Nousek; M. L. Nguyen; P. Ochner; D. N. Okhmat; S. Paltani; J. R. Parks; C. Pinto; A. Pizzella; R. Poleski; G. Ponti; J. U. Pott; S. E. Rafter; H. W. Rix; J. Runnoe; D. A. Saylor; J. S. Schimoia; K. Schnülle; B. Scott; S. G. Sergeev; B. J. Shappee; I. Shivvers; M. Siegel; G. V. Simonian; A. Siviero; A. Skielboe; G. Somers; M. Spencer; D. Starkey; D. J. Stevens; H. I. Sung; J. Tayar; K. G. Teems; T. Treu; C. S. Turner; P. Uttley; J. Van Saders; L. Vican; C. Villforth; S. Villanueva; D. J. Walton; T. Waters; Y. Weiss; J. H. Woo; H. Yan; H. Yuk; W. Zheng; W. Zhu; Y. Zu

doi:10.3847/1538-4357/ab3049

Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum

G. A. Kriss, G. De Rosa, J. Ely, B. M. Peterson, J. Kaastra, M. Mehdipour, G. J. Ferland, M. Dehghanian, S. Mathur, R. Edelson, K. T. Korista, N. Arav, A. J. Barth, M. C. Bentz, W. N. Brandt, D. M. Crenshaw, Elena Dalla Bontà, K. D. Denney, C. Done, M. EracleousM. M. Fausnaugh, E. Gardner, M. R. Goad, C. J. Grier, Keith Horne, C. S. Kochanek, I. M. McHardy, H. Netzer, A. Pancoast, L. Pei, R. W. Pogge, D. Proga, C. Silva, N. Tejos, M. Vestergaard, S. M. Adams, M. D. Anderson, P. Arévalo, T. G. Beatty, E. Behar, V. N. Bennert, S. Bianchi, A. Bigley, S. Bisogni, R. Boissay-Malaquin, G. A. Borman, M. C. Bottorff, A. A. Breeveld, M. Brotherton, J. E. Brown, J. S. Brown, E. M. Cackett, G. Canalizo, M. Cappi, M. T. Carini, K. I. Clubb, J. M. Comerford, C. T. Coker, E. M. Corsini, E. Costantini, S. Croft, K. V. Croxall, A. J. Deason, A. De Lorenzo-Cáceres, B. De Marco, M. Dietrich, L. Di Gesu, J. Ebrero, P. A. Evans, A. V. Filippenko, K. Flatland, E. L. Gates, N. Gehrels, S. Geier, J. M. Gelbord, L. Gonzalez, V. Gorjian, D. Grupe, A. Gupta, P. B. Hall, C. B. Henderson, S. Hicks, E. Holmbeck, T. W.S. Holoien, T. A. Hutchison, M. Im, J. J. Jensen, C. A. Johnson, M. D. Joner, S. Kaspi, B. C. Kelly, P. L. Kelly, J. A. Kennea, M. Kim, S. C. Kim, S. Y. Kim, A. King, S. A. Klimanov, Y. Krongold, M. W. Lau, J. C. Lee, D. C. Leonard, Miao Li, P. Lira, C. Lochhaas, Zhiyuan Ma, F. Macinnis, M. A. Malkan, E. R. Manne-Nicholas, G. Matt, J. C. Mauerhan, R. McGurk, C. Montuori, L. Morelli, A. Mosquera, D. Mudd, F. Müller-Sánchez, S. V. Nazarov, R. P. Norris, J. A. Nousek, M. L. Nguyen, P. Ochner, D. N. Okhmat, S. Paltani, J. R. Parks, C. Pinto, A. Pizzella, R. Poleski, G. Ponti, J. U. Pott, S. E. Rafter, H. W. Rix, J. Runnoe, D. A. Saylor, J. S. Schimoia, K. Schnülle, B. Scott, S. G. Sergeev, B. J. Shappee, I. Shivvers, M. Siegel, G. V. Simonian, A. Siviero, A. Skielboe, G. Somers, M. Spencer, D. Starkey, D. J. Stevens, H. I. Sung, J. Tayar, K. G. Teems, T. Treu, C. S. Turner, P. Uttley, J. Van Saders, L. Vican, C. Villforth, S. Villanueva, D. J. Walton, T. Waters, Y. Weiss, J. H. Woo, H. Yan, H. Yuk, W. Zheng, W. Zhu, Y. Zu

Research output: Contribution to journal › Article › peer-review

36 Scopus citations

Abstract

We model the ultraviolet spectra of the Seyfert 1 galaxy NGC 5548 obtained with the Hubble Space Telescope during the 6 month reverberation mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Ly and C iv, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original data. The velocity-binned lag profiles of Ly and C iv have a double-peaked structure indicative of a truncated Keplerian disk. The narrow absorption lines show a delayed response to continuum variations corresponding to recombination in gas with a density of ∼10⁵ cm^-3. The high-ionization narrow absorption lines decorrelate from continuum variations during the same period as the broad emission lines. Analyzing the response of these absorption lines during this period shows that the ionizing flux is diminished in strength relative to the far-ultraviolet continuum. The broad absorption lines associated with the X-ray obscurer decrease in strength during this same time interval. The appearance of X-ray obscuration in ∼2012 corresponds with an increase in the luminosity of NGC 5548 following an extended low state. We suggest that the obscurer is a disk wind triggered by the brightening of NGC 5548 following the decrease in size of the broad-line region during the preceding low-luminosity state.

Original language	English
Article number	153
Journal	Astrophysical Journal
Volume	881
Issue number	2
DOIs	https://doi.org/10.3847/1538-4357/ab3049
State	Published - Aug 20 2019

Bibliographical note

Publisher Copyright:
© 2019. The American Astronomical Society..

Keywords

galaxies: Seyfert
galaxies: active
galaxies: individual (NGC 5548)
galaxies: nuclei

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Access to Document

10.3847/1538-4357/ab3049

Cite this

Kriss, G. A., De Rosa, G., Ely, J., Peterson, B. M., Kaastra, J., Mehdipour, M., Ferland, G. J., Dehghanian, M., Mathur, S., Edelson, R., Korista, K. T., Arav, N., Barth, A. J., Bentz, M. C., Brandt, W. N., Crenshaw, D. M., Dalla Bontà, E., Denney, K. D., Done, C., ... Zu, Y. (2019). Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum. Astrophysical Journal, 881(2), Article 153. https://doi.org/10.3847/1538-4357/ab3049

@article{16ceb191e22447e78f4f3ecf3a25fe1e,

title = "Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum",

abstract = "We model the ultraviolet spectra of the Seyfert 1 galaxy NGC 5548 obtained with the Hubble Space Telescope during the 6 month reverberation mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Ly and C iv, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original data. The velocity-binned lag profiles of Ly and C iv have a double-peaked structure indicative of a truncated Keplerian disk. The narrow absorption lines show a delayed response to continuum variations corresponding to recombination in gas with a density of ∼105 cm-3. The high-ionization narrow absorption lines decorrelate from continuum variations during the same period as the broad emission lines. Analyzing the response of these absorption lines during this period shows that the ionizing flux is diminished in strength relative to the far-ultraviolet continuum. The broad absorption lines associated with the X-ray obscurer decrease in strength during this same time interval. The appearance of X-ray obscuration in ∼2012 corresponds with an increase in the luminosity of NGC 5548 following an extended low state. We suggest that the obscurer is a disk wind triggered by the brightening of NGC 5548 following the decrease in size of the broad-line region during the preceding low-luminosity state.",

keywords = "galaxies: Seyfert, galaxies: active, galaxies: individual (NGC 5548), galaxies: nuclei",

author = "Kriss, {G. A.} and {De Rosa}, G. and J. Ely and Peterson, {B. M.} and J. Kaastra and M. Mehdipour and Ferland, {G. J.} and M. Dehghanian and S. Mathur and R. Edelson and Korista, {K. T.} and N. Arav and Barth, {A. J.} and Bentz, {M. C.} and Brandt, {W. N.} and Crenshaw, {D. M.} and {Dalla Bont{\`a}}, Elena and Denney, {K. D.} and C. Done and M. Eracleous and Fausnaugh, {M. M.} and E. Gardner and Goad, {M. R.} and Grier, {C. J.} and Keith Horne and Kochanek, {C. S.} and McHardy, {I. M.} and H. Netzer and A. Pancoast and L. Pei and Pogge, {R. W.} and D. Proga and C. Silva and N. Tejos and M. Vestergaard and Adams, {S. M.} and Anderson, {M. D.} and P. Ar{\'e}valo and Beatty, {T. G.} and E. Behar and Bennert, {V. N.} and S. Bianchi and A. Bigley and S. Bisogni and R. Boissay-Malaquin and Borman, {G. A.} and Bottorff, {M. C.} and Breeveld, {A. A.} and M. Brotherton and Brown, {J. E.} and Brown, {J. S.} and Cackett, {E. M.} and G. Canalizo and M. Cappi and Carini, {M. T.} and Clubb, {K. I.} and Comerford, {J. M.} and Coker, {C. T.} and Corsini, {E. M.} and E. Costantini and S. Croft and Croxall, {K. V.} and Deason, {A. J.} and {De Lorenzo-C{\'a}ceres}, A. and {De Marco}, B. and M. Dietrich and {Di Gesu}, L. and J. Ebrero and Evans, {P. A.} and Filippenko, {A. V.} and K. Flatland and Gates, {E. L.} and N. Gehrels and S. Geier and Gelbord, {J. M.} and L. Gonzalez and V. Gorjian and D. Grupe and A. Gupta and Hall, {P. B.} and Henderson, {C. B.} and S. Hicks and E. Holmbeck and Holoien, {T. W.S.} and Hutchison, {T. A.} and M. Im and Jensen, {J. J.} and Johnson, {C. A.} and Joner, {M. D.} and S. Kaspi and Kelly, {B. C.} and Kelly, {P. L.} and Kennea, {J. A.} and M. Kim and Kim, {S. C.} and Kim, {S. Y.} and A. King and Klimanov, {S. A.} and Y. Krongold and Lau, {M. W.} and Lee, {J. C.} and Leonard, {D. C.} and Miao Li and P. Lira and C. Lochhaas and Zhiyuan Ma and F. Macinnis and Malkan, {M. A.} and Manne-Nicholas, {E. R.} and G. Matt and Mauerhan, {J. C.} and R. McGurk and C. Montuori and L. Morelli and A. Mosquera and D. Mudd and F. M{\"u}ller-S{\'a}nchez and Nazarov, {S. V.} and Norris, {R. P.} and Nousek, {J. A.} and Nguyen, {M. L.} and P. Ochner and Okhmat, {D. N.} and S. Paltani and Parks, {J. R.} and C. Pinto and A. Pizzella and R. Poleski and G. Ponti and Pott, {J. U.} and Rafter, {S. E.} and Rix, {H. W.} and J. Runnoe and Saylor, {D. A.} and Schimoia, {J. S.} and K. Schn{\"u}lle and B. Scott and Sergeev, {S. G.} and Shappee, {B. J.} and I. Shivvers and M. Siegel and Simonian, {G. V.} and A. Siviero and A. Skielboe and G. Somers and M. Spencer and D. Starkey and Stevens, {D. J.} and Sung, {H. I.} and J. Tayar and Teems, {K. G.} and T. Treu and Turner, {C. S.} and P. Uttley and {Van Saders}, J. and L. Vican and C. Villforth and S. Villanueva and Walton, {D. J.} and T. Waters and Y. Weiss and Woo, {J. H.} and H. Yan and H. Yuk and W. Zheng and W. Zhu and Y. Zu",

note = "Publisher Copyright: {\textcopyright} 2019. The American Astronomical Society..",

year = "2019",

month = aug,

day = "20",

doi = "10.3847/1538-4357/ab3049",

language = "English",

volume = "881",

number = "2",

}

Kriss, GA, De Rosa, G, Ely, J, Peterson, BM, Kaastra, J, Mehdipour, M, Ferland, GJ, Dehghanian, M, Mathur, S, Edelson, R, Korista, KT, Arav, N, Barth, AJ, Bentz, MC, Brandt, WN, Crenshaw, DM, Dalla Bontà, E, Denney, KD, Done, C, Eracleous, M, Fausnaugh, MM, Gardner, E, Goad, MR, Grier, CJ, Horne, K, Kochanek, CS, McHardy, IM, Netzer, H, Pancoast, A, Pei, L, Pogge, RW, Proga, D, Silva, C, Tejos, N, Vestergaard, M, Adams, SM, Anderson, MD, Arévalo, P, Beatty, TG, Behar, E, Bennert, VN, Bianchi, S, Bigley, A, Bisogni, S, Boissay-Malaquin, R, Borman, GA, Bottorff, MC, Breeveld, AA, Brotherton, M, Brown, JE, Brown, JS, Cackett, EM, Canalizo, G, Cappi, M, Carini, MT, Clubb, KI, Comerford, JM, Coker, CT, Corsini, EM, Costantini, E, Croft, S, Croxall, KV, Deason, AJ, De Lorenzo-Cáceres, A, De Marco, B, Dietrich, M, Di Gesu, L, Ebrero, J, Evans, PA, Filippenko, AV, Flatland, K, Gates, EL, Gehrels, N, Geier, S, Gelbord, JM, Gonzalez, L, Gorjian, V, Grupe, D, Gupta, A, Hall, PB, Henderson, CB, Hicks, S, Holmbeck, E, Holoien, TWS, Hutchison, TA, Im, M, Jensen, JJ, Johnson, CA, Joner, MD, Kaspi, S, Kelly, BC, Kelly, PL, Kennea, JA, Kim, M, Kim, SC, Kim, SY, King, A, Klimanov, SA, Krongold, Y, Lau, MW, Lee, JC, Leonard, DC, Li, M, Lira, P, Lochhaas, C, Ma, Z, Macinnis, F, Malkan, MA, Manne-Nicholas, ER, Matt, G, Mauerhan, JC, McGurk, R, Montuori, C, Morelli, L, Mosquera, A, Mudd, D, Müller-Sánchez, F, Nazarov, SV, Norris, RP, Nousek, JA, Nguyen, ML, Ochner, P, Okhmat, DN, Paltani, S, Parks, JR, Pinto, C, Pizzella, A, Poleski, R, Ponti, G, Pott, JU, Rafter, SE, Rix, HW, Runnoe, J, Saylor, DA, Schimoia, JS, Schnülle, K, Scott, B, Sergeev, SG, Shappee, BJ, Shivvers, I, Siegel, M, Simonian, GV, Siviero, A, Skielboe, A, Somers, G, Spencer, M, Starkey, D, Stevens, DJ, Sung, HI, Tayar, J, Teems, KG, Treu, T, Turner, CS, Uttley, P, Van Saders, J, Vican, L, Villforth, C, Villanueva, S, Walton, DJ, Waters, T, Weiss, Y, Woo, JH, Yan, H, Yuk, H, Zheng, W, Zhu, W & Zu, Y 2019, 'Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum', Astrophysical Journal, vol. 881, no. 2, 153. https://doi.org/10.3847/1538-4357/ab3049

TY - JOUR

T1 - Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum

AU - Kriss, G. A.

AU - De Rosa, G.

AU - Ely, J.

AU - Peterson, B. M.

AU - Kaastra, J.

AU - Mehdipour, M.

AU - Ferland, G. J.

AU - Dehghanian, M.

AU - Mathur, S.

AU - Edelson, R.

AU - Korista, K. T.

AU - Arav, N.

AU - Barth, A. J.

AU - Bentz, M. C.

AU - Brandt, W. N.

AU - Crenshaw, D. M.

AU - Dalla Bontà, Elena

AU - Denney, K. D.

AU - Done, C.

AU - Eracleous, M.

AU - Fausnaugh, M. M.

AU - Gardner, E.

AU - Goad, M. R.

AU - Grier, C. J.

AU - Horne, Keith

AU - Kochanek, C. S.

AU - McHardy, I. M.

AU - Netzer, H.

AU - Pancoast, A.

AU - Pei, L.

AU - Pogge, R. W.

AU - Proga, D.

AU - Silva, C.

AU - Tejos, N.

AU - Vestergaard, M.

AU - Adams, S. M.

AU - Anderson, M. D.

AU - Arévalo, P.

AU - Beatty, T. G.

AU - Behar, E.

AU - Bennert, V. N.

AU - Bianchi, S.

AU - Bigley, A.

AU - Bisogni, S.

AU - Boissay-Malaquin, R.

AU - Borman, G. A.

AU - Bottorff, M. C.

AU - Breeveld, A. A.

AU - Brotherton, M.

AU - Brown, J. E.

AU - Brown, J. S.

AU - Cackett, E. M.

AU - Canalizo, G.

AU - Cappi, M.

AU - Carini, M. T.

AU - Clubb, K. I.

AU - Comerford, J. M.

AU - Coker, C. T.

AU - Corsini, E. M.

AU - Costantini, E.

AU - Croft, S.

AU - Croxall, K. V.

AU - Deason, A. J.

AU - De Lorenzo-Cáceres, A.

AU - De Marco, B.

AU - Dietrich, M.

AU - Di Gesu, L.

AU - Ebrero, J.

AU - Evans, P. A.

AU - Filippenko, A. V.

AU - Flatland, K.

AU - Gates, E. L.

AU - Gehrels, N.

AU - Geier, S.

AU - Gelbord, J. M.

AU - Gonzalez, L.

AU - Gorjian, V.

AU - Grupe, D.

AU - Gupta, A.

AU - Hall, P. B.

AU - Henderson, C. B.

AU - Hicks, S.

AU - Holmbeck, E.

AU - Holoien, T. W.S.

AU - Hutchison, T. A.

AU - Im, M.

AU - Jensen, J. J.

AU - Johnson, C. A.

AU - Joner, M. D.

AU - Kaspi, S.

AU - Kelly, B. C.

AU - Kelly, P. L.

AU - Kennea, J. A.

AU - Kim, M.

AU - Kim, S. C.

AU - Kim, S. Y.

AU - King, A.

AU - Klimanov, S. A.

AU - Krongold, Y.

AU - Lau, M. W.

AU - Lee, J. C.

AU - Leonard, D. C.

AU - Li, Miao

AU - Lira, P.

AU - Lochhaas, C.

AU - Ma, Zhiyuan

AU - Macinnis, F.

AU - Malkan, M. A.

AU - Manne-Nicholas, E. R.

AU - Matt, G.

AU - Mauerhan, J. C.

AU - McGurk, R.

AU - Montuori, C.

AU - Morelli, L.

AU - Mosquera, A.

AU - Mudd, D.

AU - Müller-Sánchez, F.

AU - Nazarov, S. V.

AU - Norris, R. P.

AU - Nousek, J. A.

AU - Nguyen, M. L.

AU - Ochner, P.

AU - Okhmat, D. N.

AU - Paltani, S.

AU - Parks, J. R.

AU - Pinto, C.

AU - Pizzella, A.

AU - Poleski, R.

AU - Ponti, G.

AU - Pott, J. U.

AU - Rafter, S. E.

AU - Rix, H. W.

AU - Runnoe, J.

AU - Saylor, D. A.

AU - Schimoia, J. S.

AU - Schnülle, K.

AU - Scott, B.

AU - Sergeev, S. G.

AU - Shappee, B. J.

AU - Shivvers, I.

AU - Siegel, M.

AU - Simonian, G. V.

AU - Siviero, A.

AU - Skielboe, A.

AU - Somers, G.

AU - Spencer, M.

AU - Starkey, D.

AU - Stevens, D. J.

AU - Sung, H. I.

AU - Tayar, J.

AU - Teems, K. G.

AU - Treu, T.

AU - Turner, C. S.

AU - Uttley, P.

AU - Van Saders, J.

AU - Vican, L.

AU - Villforth, C.

AU - Villanueva, S.

AU - Walton, D. J.

AU - Waters, T.

AU - Weiss, Y.

AU - Woo, J. H.

AU - Yan, H.

AU - Yuk, H.

AU - Zheng, W.

AU - Zhu, W.

AU - Zu, Y.

PY - 2019/8/20

Y1 - 2019/8/20

N2 - We model the ultraviolet spectra of the Seyfert 1 galaxy NGC 5548 obtained with the Hubble Space Telescope during the 6 month reverberation mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Ly and C iv, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original data. The velocity-binned lag profiles of Ly and C iv have a double-peaked structure indicative of a truncated Keplerian disk. The narrow absorption lines show a delayed response to continuum variations corresponding to recombination in gas with a density of ∼105 cm-3. The high-ionization narrow absorption lines decorrelate from continuum variations during the same period as the broad emission lines. Analyzing the response of these absorption lines during this period shows that the ionizing flux is diminished in strength relative to the far-ultraviolet continuum. The broad absorption lines associated with the X-ray obscurer decrease in strength during this same time interval. The appearance of X-ray obscuration in ∼2012 corresponds with an increase in the luminosity of NGC 5548 following an extended low state. We suggest that the obscurer is a disk wind triggered by the brightening of NGC 5548 following the decrease in size of the broad-line region during the preceding low-luminosity state.

AB - We model the ultraviolet spectra of the Seyfert 1 galaxy NGC 5548 obtained with the Hubble Space Telescope during the 6 month reverberation mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Ly and C iv, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original data. The velocity-binned lag profiles of Ly and C iv have a double-peaked structure indicative of a truncated Keplerian disk. The narrow absorption lines show a delayed response to continuum variations corresponding to recombination in gas with a density of ∼105 cm-3. The high-ionization narrow absorption lines decorrelate from continuum variations during the same period as the broad emission lines. Analyzing the response of these absorption lines during this period shows that the ionizing flux is diminished in strength relative to the far-ultraviolet continuum. The broad absorption lines associated with the X-ray obscurer decrease in strength during this same time interval. The appearance of X-ray obscuration in ∼2012 corresponds with an increase in the luminosity of NGC 5548 following an extended low state. We suggest that the obscurer is a disk wind triggered by the brightening of NGC 5548 following the decrease in size of the broad-line region during the preceding low-luminosity state.

KW - galaxies: Seyfert

KW - galaxies: active

KW - galaxies: individual (NGC 5548)

KW - galaxies: nuclei

UR - http://www.scopus.com/inward/record.url?scp=85072346415&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85072346415&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/ab3049

DO - 10.3847/1538-4357/ab3049

M3 - Article

AN - SCOPUS:85072346415

SN - 0004-637X

VL - 881

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

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Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum

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