Space telescope and optical reverberation mapping project. III. Optical continuum emission and broadband time delays in NGC 5548

M. M. Fausnaugh, K. D. Denney, A. J. Barth, M. C. Bentz, M. C. Bottorff, M. T. Carini, K. V. Croxall, G. De Rosa, M. R. Goad, K. Horne, M. D. Joner, S. Kaspi, M. Kim, S. A. Klimanov, C. S. Kochanek, D. C. Leonard, H. Netzer, B. M. Peterson, K. Schnülle, S. G. Sergeev & 77 others M. Vestergaard, W. K. Zheng, Y. Zu, M. D. Anderson, P. Arévalo, C. Bazhaw, G. A. Borman, T. A. Boroson, W. N. Brandt, A. A. Breeveld, B. J. Brewer, E. M. Cackett, D. M. Crenshaw, E. Dalla Bontà, A. De Lorenzo-Cáceres, M. Dietrich, R. Edelson, N. V. Efimova, J. Ely, P. A. Evans, A. V. Filippenko, K. Flatland, N. Gehrels, S. Geier, J. M. Gelbord, L. Gonzalez, V. Gorjian, C. J. Grier, D. Grupe, P.~B. Hall, S. Hicks, D. Horenstein, T. Hutchison, M. Im, J. J. Jensen, J. Jones, J. Kaastra, B. C. Kelly, J. A. Kennea, S. C. Kim, K. T. Korista, G. A. Kriss, J. C. Lee, P. Lira, F. MacInnis, E. R. Manne-Nicholas, S. Mathur, I. M. McHardy, C. Montouri, R. Musso, S. V. Nazarov, R. P. Norris, J. A. Nousek, D. N. Okhmat, A. Pancoast, I. Papadakis, J. R. Parks, L. Pei, R. W. Pogge, J. U. Pott, S. E. Rafter, H. W. Rix, D. A. Saylor, J. S. Schimoia, M. Siegel, M. Spencer, D. Starkey, H. I. Sung, K. G. Teems, T. Treu, C. S. Turner, P. Uttley, C. Villforth, Y. Weiss, J. H. Woo, H. Yan, S. Young

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Abstract

We present ground-based optical photometric monitoring data for NGC 5548, part of an extended multiwavelength reverberation mapping campaign. The light curves have nearly daily cadence from 2014 January to July in nine filters (BVRI and ugriz). Combined with ultraviolet data from the Hubble Space Telescope and Swift, we confirm significant time delays between the continuum bands as a function of wavelength, extending the wavelength coverage from 1158 Å to the z band (~9160 Å). We find that the lags at wavelengths longer than the V band are equal to or greater than the lags of high-ionization-state emission lines (such as He ii $\lambda 1640$ and $\lambda 4686$), suggesting that the continuum-emitting source is of a physical size comparable to the inner broad-line region (BLR). The trend of lag with wavelength is broadly consistent with the prediction for continuum reprocessing by an accretion disk with $\tau \propto {\lambda }^{4/3}$. However, the lags also imply a disk radius that is 3 times larger than the prediction from standard thin-disk theory, assuming that the bolometric luminosity is 10% of the Eddington luminosity ($L=0.1{L}_{{\rm{Edd}}}$). Using optical spectra from the Large Binocular Telescope, we estimate the bias of the interband continuum lags due to BLR emission observed in the filters. We find that the bias for filters with high levels of BLR contamination (~20%) can be important for the shortest continuum lags and likely has a significant impact on the u and U bands owing to Balmer continuum emission.
Original languageEnglish
Pages (from-to)1 - 25
Number of pages25
JournalAstrophysical Journal
Volume821
Issue number1
DOIs
Publication statusPublished - 10 Apr 2016

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reverberation
time lag
telescopes
continuums
broadband
wavelength
filter
filters
wavelengths
prediction
luminosity
ionization
accretion
extremely high frequencies
predictions
project
Hubble Space Telescope
accretion disks
light curve
optical spectrum

Keywords

  • galaxies: active, galaxies: individual: NGC 5548, galaxies: nuclei, galaxies: Seyfert

Cite this

Fausnaugh, M. M., Denney, K. D., Barth, A. J., Bentz, M. C., Bottorff, M. C., Carini, M. T., ... Young, S. (2016). Space telescope and optical reverberation mapping project. III. Optical continuum emission and broadband time delays in NGC 5548. Astrophysical Journal, 821(1), 1 - 25. https://doi.org/10.3847/0004-637X/821/1/56

Space telescope and optical reverberation mapping project. III. Optical continuum emission and broadband time delays in NGC 5548. / Fausnaugh, M. M.; Denney, K. D.; Barth, A. J.; Bentz, M. C.; Bottorff, M. C.; Carini, M. T.; Croxall, K. V.; De Rosa, G.; Goad, M. R.; Horne, K.; Joner, M. D.; Kaspi, S.; Kim, M.; Klimanov, S. A.; Kochanek, C. S.; Leonard, D. C.; Netzer, H.; Peterson, B. M.; Schnülle, K.; Sergeev, S. G.; Vestergaard, M.; Zheng, W. K.; Zu, Y.; Anderson, M. D.; Arévalo, P.; Bazhaw, C.; Borman, G. A.; Boroson, T. A.; Brandt, W. N.; Breeveld, A. A.; Brewer, B. J.; Cackett, E. M.; Crenshaw, D. M.; Dalla Bontà, E.; De Lorenzo-Cáceres, A.; Dietrich, M.; Edelson, R.; Efimova, N. V.; Ely, J.; Evans, P. A.; Filippenko, A. V.; Flatland, K.; Gehrels, N.; Geier, S.; Gelbord, J. M.; Gonzalez, L.; Gorjian, V.; Grier, C. J.; Grupe, D.; Hall, P.~B.; Hicks, S.; Horenstein, D.; Hutchison, T.; Im, M.; Jensen, J. J.; Jones, J.; Kaastra, J.; Kelly, B. C.; Kennea, J. A.; Kim, S. C.; Korista, K. T.; Kriss, G. A.; Lee, J. C.; Lira, P.; MacInnis, F.; Manne-Nicholas, E. R.; Mathur, S.; McHardy, I. M.; Montouri, C.; Musso, R.; Nazarov, S. V.; Norris, R. P.; Nousek, J. A.; Okhmat, D. N.; Pancoast, A.; Papadakis, I.; Parks, J. R.; Pei, L.; Pogge, R. W.; Pott, J. U.; Rafter, S. E.; Rix, H. W.; Saylor, D. A.; Schimoia, J. S.; Siegel, M.; Spencer, M.; Starkey, D.; Sung, H. I.; Teems, K. G.; Treu, T.; Turner, C. S.; Uttley, P.; Villforth, C.; Weiss, Y.; Woo, J. H.; Yan, H.; Young, S.

In: Astrophysical Journal, Vol. 821, No. 1, 10.04.2016, p. 1 - 25.

Research output: Contribution to journalArticle

Fausnaugh, MM, Denney, KD, Barth, AJ, Bentz, MC, Bottorff, MC, Carini, MT, Croxall, KV, De Rosa, G, Goad, MR, Horne, K, Joner, MD, Kaspi, S, Kim, M, Klimanov, SA, Kochanek, CS, Leonard, DC, Netzer, H, Peterson, BM, Schnülle, K, Sergeev, SG, Vestergaard, M, Zheng, WK, Zu, Y, Anderson, MD, Arévalo, P, Bazhaw, C, Borman, GA, Boroson, TA, Brandt, WN, Breeveld, AA, Brewer, BJ, Cackett, EM, Crenshaw, DM, Dalla Bontà, E, De Lorenzo-Cáceres, A, Dietrich, M, Edelson, R, Efimova, NV, Ely, J, Evans, PA, Filippenko, AV, Flatland, K, Gehrels, N, Geier, S, Gelbord, JM, Gonzalez, L, Gorjian, V, Grier, CJ, Grupe, D, Hall, PB, Hicks, S, Horenstein, D, Hutchison, T, Im, M, Jensen, JJ, Jones, J, Kaastra, J, Kelly, BC, Kennea, JA, Kim, SC, Korista, KT, Kriss, GA, Lee, JC, Lira, P, MacInnis, F, Manne-Nicholas, ER, Mathur, S, McHardy, IM, Montouri, C, Musso, R, Nazarov, SV, Norris, RP, Nousek, JA, Okhmat, DN, Pancoast, A, Papadakis, I, Parks, JR, Pei, L, Pogge, RW, Pott, JU, Rafter, SE, Rix, HW, Saylor, DA, Schimoia, JS, Siegel, M, Spencer, M, Starkey, D, Sung, HI, Teems, KG, Treu, T, Turner, CS, Uttley, P, Villforth, C, Weiss, Y, Woo, JH, Yan, H & Young, S 2016, 'Space telescope and optical reverberation mapping project. III. Optical continuum emission and broadband time delays in NGC 5548', Astrophysical Journal, vol. 821, no. 1, pp. 1 - 25. https://doi.org/10.3847/0004-637X/821/1/56
Fausnaugh, M. M. ; Denney, K. D. ; Barth, A. J. ; Bentz, M. C. ; Bottorff, M. C. ; Carini, M. T. ; Croxall, K. V. ; De Rosa, G. ; Goad, M. R. ; Horne, K. ; Joner, M. D. ; Kaspi, S. ; Kim, M. ; Klimanov, S. A. ; Kochanek, C. S. ; Leonard, D. C. ; Netzer, H. ; Peterson, B. M. ; Schnülle, K. ; Sergeev, S. G. ; Vestergaard, M. ; Zheng, W. K. ; Zu, Y. ; Anderson, M. D. ; Arévalo, P. ; Bazhaw, C. ; Borman, G. A. ; Boroson, T. A. ; Brandt, W. N. ; Breeveld, A. A. ; Brewer, B. J. ; Cackett, E. M. ; Crenshaw, D. M. ; Dalla Bontà, E. ; De Lorenzo-Cáceres, A. ; Dietrich, M. ; Edelson, R. ; Efimova, N. V. ; Ely, J. ; Evans, P. A. ; Filippenko, A. V. ; Flatland, K. ; Gehrels, N. ; Geier, S. ; Gelbord, J. M. ; Gonzalez, L. ; Gorjian, V. ; Grier, C. J. ; Grupe, D. ; Hall, P.~B. ; Hicks, S. ; Horenstein, D. ; Hutchison, T. ; Im, M. ; Jensen, J. J. ; Jones, J. ; Kaastra, J. ; Kelly, B. C. ; Kennea, J. A. ; Kim, S. C. ; Korista, K. T. ; Kriss, G. A. ; Lee, J. C. ; Lira, P. ; MacInnis, F. ; Manne-Nicholas, E. R. ; Mathur, S. ; McHardy, I. M. ; Montouri, C. ; Musso, R. ; Nazarov, S. V. ; Norris, R. P. ; Nousek, J. A. ; Okhmat, D. N. ; Pancoast, A. ; Papadakis, I. ; Parks, J. R. ; Pei, L. ; Pogge, R. W. ; Pott, J. U. ; Rafter, S. E. ; Rix, H. W. ; Saylor, D. A. ; Schimoia, J. S. ; Siegel, M. ; Spencer, M. ; Starkey, D. ; Sung, H. I. ; Teems, K. G. ; Treu, T. ; Turner, C. S. ; Uttley, P. ; Villforth, C. ; Weiss, Y. ; Woo, J. H. ; Yan, H. ; Young, S. / Space telescope and optical reverberation mapping project. III. Optical continuum emission and broadband time delays in NGC 5548. In: Astrophysical Journal. 2016 ; Vol. 821, No. 1. pp. 1 - 25.
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abstract = "We present ground-based optical photometric monitoring data for NGC 5548, part of an extended multiwavelength reverberation mapping campaign. The light curves have nearly daily cadence from 2014 January to July in nine filters (BVRI and ugriz). Combined with ultraviolet data from the Hubble Space Telescope and Swift, we confirm significant time delays between the continuum bands as a function of wavelength, extending the wavelength coverage from 1158 {\AA} to the z band (~9160 {\AA}). We find that the lags at wavelengths longer than the V band are equal to or greater than the lags of high-ionization-state emission lines (such as He ii $\lambda 1640$ and $\lambda 4686$), suggesting that the continuum-emitting source is of a physical size comparable to the inner broad-line region (BLR). The trend of lag with wavelength is broadly consistent with the prediction for continuum reprocessing by an accretion disk with $\tau \propto {\lambda }^{4/3}$. However, the lags also imply a disk radius that is 3 times larger than the prediction from standard thin-disk theory, assuming that the bolometric luminosity is 10{\%} of the Eddington luminosity ($L=0.1{L}_{{\rm{Edd}}}$). Using optical spectra from the Large Binocular Telescope, we estimate the bias of the interband continuum lags due to BLR emission observed in the filters. We find that the bias for filters with high levels of BLR contamination (~20{\%}) can be important for the shortest continuum lags and likely has a significant impact on the u and U bands owing to Balmer continuum emission.",
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TY - JOUR

T1 - Space telescope and optical reverberation mapping project. III. Optical continuum emission and broadband time delays in NGC 5548

AU - Fausnaugh, M. M.

AU - Denney, K. D.

AU - Barth, A. J.

AU - Bentz, M. C.

AU - Bottorff, M. C.

AU - Carini, M. T.

AU - Croxall, K. V.

AU - De Rosa, G.

AU - Goad, M. R.

AU - Horne, K.

AU - Joner, M. D.

AU - Kaspi, S.

AU - Kim, M.

AU - Klimanov, S. A.

AU - Kochanek, C. S.

AU - Leonard, D. C.

AU - Netzer, H.

AU - Peterson, B. M.

AU - Schnülle, K.

AU - Sergeev, S. G.

AU - Vestergaard, M.

AU - Zheng, W. K.

AU - Zu, Y.

AU - Anderson, M. D.

AU - Arévalo, P.

AU - Bazhaw, C.

AU - Borman, G. A.

AU - Boroson, T. A.

AU - Brandt, W. N.

AU - Breeveld, A. A.

AU - Brewer, B. J.

AU - Cackett, E. M.

AU - Crenshaw, D. M.

AU - Dalla Bontà, E.

AU - De Lorenzo-Cáceres, A.

AU - Dietrich, M.

AU - Edelson, R.

AU - Efimova, N. V.

AU - Ely, J.

AU - Evans, P. A.

AU - Filippenko, A. V.

AU - Flatland, K.

AU - Gehrels, N.

AU - Geier, S.

AU - Gelbord, J. M.

AU - Gonzalez, L.

AU - Gorjian, V.

AU - Grier, C. J.

AU - Grupe, D.

AU - Hall, P.~B.

AU - Hicks, S.

AU - Horenstein, D.

AU - Hutchison, T.

AU - Im, M.

AU - Jensen, J. J.

AU - Jones, J.

AU - Kaastra, J.

AU - Kelly, B. C.

AU - Kennea, J. A.

AU - Kim, S. C.

AU - Korista, K. T.

AU - Kriss, G. A.

AU - Lee, J. C.

AU - Lira, P.

AU - MacInnis, F.

AU - Manne-Nicholas, E. R.

AU - Mathur, S.

AU - McHardy, I. M.

AU - Montouri, C.

AU - Musso, R.

AU - Nazarov, S. V.

AU - Norris, R. P.

AU - Nousek, J. A.

AU - Okhmat, D. N.

AU - Pancoast, A.

AU - Papadakis, I.

AU - Parks, J. R.

AU - Pei, L.

AU - Pogge, R. W.

AU - Pott, J. U.

AU - Rafter, S. E.

AU - Rix, H. W.

AU - Saylor, D. A.

AU - Schimoia, J. S.

AU - Siegel, M.

AU - Spencer, M.

AU - Starkey, D.

AU - Sung, H. I.

AU - Teems, K. G.

AU - Treu, T.

AU - Turner, C. S.

AU - Uttley, P.

AU - Villforth, C.

AU - Weiss, Y.

AU - Woo, J. H.

AU - Yan, H.

AU - Young, S.

PY - 2016/4/10

Y1 - 2016/4/10

N2 - We present ground-based optical photometric monitoring data for NGC 5548, part of an extended multiwavelength reverberation mapping campaign. The light curves have nearly daily cadence from 2014 January to July in nine filters (BVRI and ugriz). Combined with ultraviolet data from the Hubble Space Telescope and Swift, we confirm significant time delays between the continuum bands as a function of wavelength, extending the wavelength coverage from 1158 Å to the z band (~9160 Å). We find that the lags at wavelengths longer than the V band are equal to or greater than the lags of high-ionization-state emission lines (such as He ii $\lambda 1640$ and $\lambda 4686$), suggesting that the continuum-emitting source is of a physical size comparable to the inner broad-line region (BLR). The trend of lag with wavelength is broadly consistent with the prediction for continuum reprocessing by an accretion disk with $\tau \propto {\lambda }^{4/3}$. However, the lags also imply a disk radius that is 3 times larger than the prediction from standard thin-disk theory, assuming that the bolometric luminosity is 10% of the Eddington luminosity ($L=0.1{L}_{{\rm{Edd}}}$). Using optical spectra from the Large Binocular Telescope, we estimate the bias of the interband continuum lags due to BLR emission observed in the filters. We find that the bias for filters with high levels of BLR contamination (~20%) can be important for the shortest continuum lags and likely has a significant impact on the u and U bands owing to Balmer continuum emission.

AB - We present ground-based optical photometric monitoring data for NGC 5548, part of an extended multiwavelength reverberation mapping campaign. The light curves have nearly daily cadence from 2014 January to July in nine filters (BVRI and ugriz). Combined with ultraviolet data from the Hubble Space Telescope and Swift, we confirm significant time delays between the continuum bands as a function of wavelength, extending the wavelength coverage from 1158 Å to the z band (~9160 Å). We find that the lags at wavelengths longer than the V band are equal to or greater than the lags of high-ionization-state emission lines (such as He ii $\lambda 1640$ and $\lambda 4686$), suggesting that the continuum-emitting source is of a physical size comparable to the inner broad-line region (BLR). The trend of lag with wavelength is broadly consistent with the prediction for continuum reprocessing by an accretion disk with $\tau \propto {\lambda }^{4/3}$. However, the lags also imply a disk radius that is 3 times larger than the prediction from standard thin-disk theory, assuming that the bolometric luminosity is 10% of the Eddington luminosity ($L=0.1{L}_{{\rm{Edd}}}$). Using optical spectra from the Large Binocular Telescope, we estimate the bias of the interband continuum lags due to BLR emission observed in the filters. We find that the bias for filters with high levels of BLR contamination (~20%) can be important for the shortest continuum lags and likely has a significant impact on the u and U bands owing to Balmer continuum emission.

KW - galaxies: active, galaxies: individual: NGC 5548, galaxies: nuclei, galaxies: Seyfert

U2 - 10.3847/0004-637X/821/1/56

DO - 10.3847/0004-637X/821/1/56

M3 - Article

VL - 821

SP - 1

EP - 25

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

ER -