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13 results on '"Bazhaw, C"'

1. Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the UV anomaly in NGC 5548 with X-Ray Spectroscopy

Author

Mathur, S., Gupta, A., Page, K., Pogge, R. W., Krongold, Y., Goad, M. R., Adams, S. M., Anderson, M. D., Arevalo, P., Barth, A. J., Bazhaw, C., Beatty, T. G., Bentz, M. C., Bigley, A., Bisogni, S., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Brown, J. E., Brown, J. S., Cackett, E. M., Canalizo, G., Carini, M. T., Clubb, K. I., Comerford, J. M., Coker, C. T., Corsini, E. M., Crenshaw, D. M., Croft, S., Croxall, K. V., Bonta, E. Dalla, Deason, A. J., Denney, K. D., De Lorenzo-Caceres, A., De Rosa, G., Dietrich, M., Edelson, R., Ely, J., Eracleous, M., Evans, P. A., Fausnaugh, M. M., Ferland, G. J., Filippenko, A. V., Flatland, K., Fox, O. D., Gates, E. L., Gehrels, N., Geier, S., Gelbord, J. M., Gorjian, V., Greene, J. E., Grier, C. J., Grupe, D., Hall, P. B., Henderson, C. B., Hicks, S., Holmbeck, E., Holoien, T. W. -S., Horenstein, D., Horne, Keith, Hutchison, T., Im, M., Jensen, J. J., Johnson, C. A., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kelly, P. L., Kennea, J. A., Kim, M., Kim, S., Kim, S. C., King, A., Klimanov, S. A., Kochanek, C. S., Korista, K. T., Kriss, G. A., Lau, M. W., Lee, J. C., Leonard, D. C., Li, M., Lira, P., Ma, Z., MacInnis, F., Manne-Nicholas, E. R., Malkan, M. A., Mauerhan, J. C., McGurk, R., McHardy, I. M., Montouri, C., Morelli, L., Mosquera, A., Mudd, D., Muller-Sanchez, F., Musso, R., Nazarov, S. V., Netzer, H., Nguyen, M. L., Norris, R. P., Nousek, J. A., Ochner, P., Okhmat, D. N., Ou-Yang, B., Pancoast, A., Papadakis, I., Parks, J. R., Pei, L., Peterson, B. M., Pizzella, A., Poleski, R., Pott, J. -U., Rafter, S. E., Rix, H. -W., Runnoe, J., Saylor, D. A., Schimoia, J. S., Schnülle, K., Sergeev, S. G., Shappee, B. J., Shivvers, I., Siegel, M., Simonian, G. V., Siviero, A., Skielboe, A., Somers, G., Spencer, M., Starkey, D., Stevens, D. J., Sung, H. -I., Tayar, J., Tejos, N., Turner, C. S., Uttley, P., Van Saders, J., Vestergaard, M., Vican, L., VillanuevaJr., S., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., Yuk, H., Zheng, W., Zhu, W., and Zu, Y.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

During the Space Telescope and Optical Reverberation Mapping Project (STORM) observations of NGC 5548, the continuum and emission-line variability became de-correlated during the second half of the 6-month long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as a 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 the 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 being due to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with 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 the three observations: the UV emission line flux decrease, the soft-excess increase, and the emission line anomaly., Comment: ApJ in press. Replaced with the accepted version

Published
2017
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2. Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-Line Analysis for NGC 5548

Author

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., Bontà, E. Dalla, 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 Jr., 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.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multi-wavelength reverberation mapping campaign. The campaign spanned six months and achieved an almost daily cadence with observations from five ground-based telescopes. The H$\beta$ and He II $\lambda$4686 broad emission-line light curves lag that of the 5100 $\AA$ optical continuum by $4.17^{+0.36}_{-0.36}$ days and $0.79^{+0.35}_{-0.34}$ days, respectively. The H$\beta$ lag relative to the 1158 $\AA$ ultraviolet continuum light curve measured by the Hubble Space Telescope is roughly $\sim$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 $\sim$50% larger than the value inferred from optical data alone. We also measured velocity-resolved emission-line lags for H$\beta$ 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 H$\beta$ and He II $\lambda$4686 emission lines to the driving continuum changed significantly halfway through the campaign, a phenomenon also observed for C IV, Ly $\alpha$, 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 H$\beta$ lag is a factor of five shorter than the expected value implied by the $R_\mathrm{BLR} - L_\mathrm{AGN}$ relation based on the past behavior of NGC 5548., Comment: 22 pages, 13 figures, accepted to ApJ

Published
2017
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3. Space Telescope and Optical Reverberation Mapping Project VI: reverberating Disk Models for NGC 5548

Author

Starkey, D., Horne, Keith, Fausnaugh, M. M., Peterson, B. M., Bentz, M. C., Kochanek, C. S., Denney, K. D., Edelson, R., Goad, M. R., De Rosa, G., Anderson, M. D., Arevalo, P., Barth, A. J., Bazhaw, C., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Cackett, E. M., Carini, M. T., Croxall, K. V., Crenshaw, D. M., Bonta, E. Dalla, De Lorenzo-Caceres, A., Dietrich, M., 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., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, S. C., Kim, M., Klimanov, S. A., Korista, K. T., Kriss, G. A., Lee, J. C., Leonard, D. 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., Parks, J. R., Pei, L., Pogge, R. W., Pott, J. -U., Rafter, S. E., Rix, H. W., Saylor, D. A., Schimoia, J. S., Schnulle, K., Sergeev, S. G., Siegel, M. H., Spencer, M., Sung, H. -I., Teems, K. G., Turner, C. S., Uttley, P., Vestergaard, M., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., Zheng, W., and Zu, Y.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We conduct a multiwavelength continuum variability study of the Seyfert 1 galaxy NGC 5548 to investigate the temperature structure of its accretion disk. The 19 overlapping continuum light curves (1158 to 9157 angstroms) combine simultaneous HST , Swift , and ground-based observations over a 180 day period from 2014 January to July. Light-curve variability is interpreted as the reverberation response of the accretion disk to irradiation by a central time-varying point source. Our model yields the disk inclination, i, temperature T1 at 1 light day from the black hole, and a temperature-radius slope, alpha. We also infer the driving light curve and find that it correlates poorly with both the hard and soft X-ray light curves, suggesting that the X-rays alone may not drive the ultraviolet and optical variability over the observing period. We also decompose the light curves into bright, faint, and mean accretion-disk spectra. These spectra lie below that expected for a standard blackbody accretion disk accreting at L/LEdd = 0.1, Comment: V2: Oops wrong title! V1: Accepted for publication in ApJ, 20 Pages, 11 Figures

Published
2016
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4. Space Telescope and Optical Reverberation Mapping Project. IV. Anomalous behavior of the broad ultraviolet emission lines in NGC 5548

Author

Goad, M. R., Korista, K. T., De Rosa, G., Kriss, G. A., Edelson, R., Barth, A. J., Ferland, G. J., Kochanek, C. S., Netzer, H., Peterson, B. M., Bentz, M. C., Bisogni, S., Crenshaw, D. M., Denney, K. D., Ely, J., Fausnaugh, M. M., Grier, C. J., Gupta, A., Horne, K. D., Kaastra, J., Pancoast, A., Pei, L., Pogge, R. W., Skielboe, A., Starkey, D., Vestergaard, M., Zu, Y., Anderson, M. D., Arevalo, P., Bazhaw, C., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Brewer, B. J., Cackett, E. M., Carini, M. T., Croxall, K. V., Bonta, E. Dalla, de Lorenzo-Caceres, A., Dietrich, M., Efimova, N. V., Evans, P. A., Filippenko, A. V., Flatland, K., Gehrels, N., Geier, S., Gelbord, G. M., Gonzalez, L., Gorjian, V., Grupe, D., Hall, P. B., Hicks, S., Horenstein, D., Hutchison, T., Im, M., Jensen, J. J., Joner, M. D., Jones, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, M., Kim, S. C., Klimanov, S. A., Larionov, V. M., Lee, J. C., Leonard, D. 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., Papadakis, I., Parks, J. R., Pott, J. -U., Rafter, S. E., Rix, H. -W., Saylor, D. A., Schimoia, J. S., Schnulle, K., Sergeev, S. G., Siegel, M., Spencer, M., Sung, H. -I., Teems, K. G., Treu, T., Turner, C. S., Uttley, P., Villforth, C., Weiss, Y., Woo, J. -H., Yan, H., Young, S., and Zheng, W. -K.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert~1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far-UV continuum and broad emission-line variations decorrelated for ~60 to 70 days, starting ~75 days after the first HST/COS observation. Following this anomalous state, the flux and variability of the broad emission lines returned to a more normal state. This transient behavior, characterised by significant deficits in flux and equivalent width of the strong broad UV emission lines, is the first of its kind to be unambiguously identified in an active galactic nucleus reverberation mapping campaign. The largest corresponding emission-line flux deficits occurred for the high-ionization collisionally excited lines, C IV and Si IV(+O IV]), and also He II(+O III]), while the anomaly in Ly-alpha was substantially smaller. This pattern of behavior indicates a depletion in the flux of photons with E_{\rm ph} > 54 eV, relative to those near 13.6 eV. We suggest two plausible mechanisms for the observed behavior: (i) temporary obscuration of the ionizing continuum incident upon BLR clouds by a moving veil of material lying between the inner accretion disk and inner BLR, perhaps resulting from an episodic ejection of material from the disk, or (ii) a temporary change in the intrinsic ionizing continuum spectral energy distribution resulting in a deficit of ionizing photons with energies > 54 eV, possibly due to a transient restructuring of the Comptonizing atmosphere above the disk. Current evidence appears to favor the latter explanation., Comment: 12 pages, 2 figures, accepted for publication in ApJ, Friday 25th March 2016. A movie of the anomalous emission-line behavior can be found in the ancilliary documents

Published
2016
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5. Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy

Author

Mathur, S, Gupta, A, Page, K, Pogge, RW, Krongold, Y, Goad, MR, Adams, SM, Anderson, MD, Arévalo, P, Barth, AJ, Bazhaw, C, Beatty, TG, Bentz, MC, Bigley, A, Bisogni, S, Borman, GA, Boroson, TA, Bottorff, MC, Brandt, WN, Breeveld, AA, Brown, JE, Brown, JS, Cackett, EM, Canalizo, G, Carini, MT, Clubb, KI, Comerford, JM, Coker, CT, Corsini, EM, Crenshaw, DM, Croft, S, Croxall, KV, Bontà, E Dalla, Deason, AJ, Denney, KD, De Lorenzo-Cáceres, A, De Rosa, G, Dietrich, M, Edelson, R, Ely, J, Eracleous, M, Evans, PA, Fausnaugh, MM, Ferland, GJ, Filippenko, AV, Flatland, K, Fox, OD, Gates, EL, Gehrels, N, Geier, S, Gelbord, JM, Gorjian, V, Greene, JE, Grier, CJ, Grupe, D, Hall, PB, Henderson, CB, Hicks, S, Holmbeck, E, Holoien, TW-S, Horenstein, D, Horne, Keith, Hutchison, T, Im, M, Jensen, JJ, Johnson, CA, Joner, MD, Jones, J, Kaastra, J, Kaspi, S, Kelly, BC, Kelly, PL, Kennea, JA, Kim, M, Kim, S, Kim, SC, King, A, Klimanov, SA, Kochanek, CS, Korista, KT, Kriss, GA, Lau, MW, Lee, JC, Leonard, DC, Li, M, Lira, P, Ma, Z, MacInnis, F, Manne-Nicholas, ER, Malkan, MA, Mauerhan, JC, McGurk, R, McHardy, IM, Montouri, C, Morelli, L, Mosquera, A, Mudd, D, Muller-Sanchez, F, Musso, R, and Nazarov, SV

Subjects
galaxies: active, galaxies: individual, X-rays: galaxies, X-rays: individual, astro-ph.GA, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

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 the 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.

Published
2017

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

Author

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, Bontà, E Dalla, Filippenko, AV, Greene, JE, Grier, CJ, Vestergaard, M, Zheng, W, Adams, Scott M, Beatty, Thomas G, Bigley, A, Brown, Jacob E, Brown, Jonathan S, Canalizo, G, Comerford, JM, Coker, Carl T, Corsini, EM, Croft, S, Croxall, KV, Deason, AJ, Eracleous, Michael, Fox, OD, Gates, EL, Henderson, CB, Holmbeck, E, Holoien, TW-S, Jensen, JJ, Johnson, CA, Kelly, PL, Kim, S, King, A, Lau, MW, Li, Miao, Lochhaas, Cassandra, Ma, Zhiyuan, Manne-Nicholas, ER, Mauerhan, JC, Malkan, MA, McGurk, R, Morelli, L, Mosquera, Ana, Mudd, Dale, Sanchez, F Muller, Nguyen, ML, Ochner, P, Ou-Yang, B, Pancoast, A, Penny, Matthew T, Pizzella, A, Poleski, Radosław, Runnoe, Jessie, Scott, B, Schimoia, Jaderson S, Shappee, BJ, Shivvers, I, Simonian, Gregory V, Siviero, A, Somers, Garrett, Stevens, Daniel J, Strauss, MA, Tayar, Jamie, 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, and Ferland, GJ

Subjects
galaxies: active, galaxies: individual, galaxies: nuclei, galaxies: Seyfert, astro-ph.GA, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
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.

Published
2017

7. SPACE TELESCOPE AND OPTICAL REVERBERATION MAPPING PROJECT.VI. REVERBERATING DISK MODELS FOR NGC 5548

Author

Starkey, D, Horne, Keith, Fausnaugh, MM, Peterson, BM, Bentz, MC, Kochanek, CS, Denney, KD, Edelson, R, Goad, MR, De Rosa, G, Anderson, MD, Arévalo, P, Barth, AJ, Bazhaw, C, Borman, GA, Boroson, TA, Bottorff, MC, Brandt, WN, Breeveld, AA, Cackett, EM, Carini, MT, Croxall, KV, Crenshaw, DM, Bontà, E Dalla, De Lorenzo-Cáceres, A, Dietrich, M, 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, Joner, MD, Jones, J, Kaastra, J, Kaspi, S, Kelly, BC, Kennea, JA, Kim, SC, Kim, M, Klimanov, SA, Korista, KT, Kriss, GA, Lee, JC, Leonard, DC, 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, Parks, JR, Pei, L, Pogge, RW, Pott, J-U, Rafter, SE, Rix, H-W, Saylor, DA, Schimoia, JS, Schnülle, K, Sergeev, SG, Siegel, MH, Spencer, M, Sung, H-I, Teems, KG, Turner, CS, Uttley, P, Vestergaard, M, Villforth, C, Weiss, Y, Woo, J-H, Yan, H, Young, and S, Zheng, W, and Zu, Y

Subjects
accretion, accretion disks, galaxies: active, galaxies: individual, galaxies: nuclei, galaxies: Seyfert, astro-ph.GA, astro-ph.HE, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

We conduct a multiwavelength continuum variability study of the Seyfert 1 galaxy NGC 5548 to investigate the temperature structure of its accretion disk. The 19 overlapping continuum light curves (1158 A oto 9157 A o) combine simultaneous Hubble Space Telescope, Swift, and ground-based observations over a 180 day period from 2014 January to July. Light-curve variability is interpreted as the reverberation response of the accretion disk to irradiation by a central time-varying point source. Our model yields the disk inclination i = 36° ±10° temperature T1 = 44 ±6 ) × 10 3 K at 1 light day from the black hole, and a temperatureradius slope (T ∞r-a) of a = 0.99 ±0.03. We also infer the driving light curve and find that it correlates poorly with both the hard and soft X-ray light curves, suggesting that the X-rays alone may not drive the ultraviolet and optical variability over the observing period. We also decompose the light curves into bright, faint, and mean accretion-disk spectra. These spectra lie below that expected for a standard blackbody accretion disk accreting at L LEdd = 0.1.

Published
2017

8. Space Telescope and Optical Reverberation Mapping Project. III. Optical Continuum Emission and Broad-Band Time Delays in NGC 5548

Author

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, Keith, Joner, M. D., Kaspi, S., Kim, M., Klimanov, S. A., Kochanek, C. S., Leonard, D. C., Netzer, H., Peterson, B. M., Schnulle, K., Sergeev, S. G., Vestergaard, M., Zheng, W. -K., Zu, Y., Anderson, M. D., Arevalo, P., Bazhaw, C., Borman, G. A., Boroson, T. A., Brandt, W. N., Breeveld, A. A., Brewer, B. J., Cackett, E. M., Crenshaw, D. M., Bonta, E. Dalla, De Lorenzo-Caceres, 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., and Young, S.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present ground-based optical photometric monitoring data for NGC 5548, part of an extended multi-wavelength reverberation mapping campaign. The light curves have nearly daily cadence from 2014 January to July in nine filters (\emph{BVRI} and \emph{ugriz}). Combined with ultraviolet data from the \emph{Hubble Space Telescope} and \emph{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 ($\sim\!9160$\,\AA). We find that the lags at wavelengths longer than the {\it V} band are equal to or greater than the lags of high-ionization-state emission lines (such as He\,{\sc 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 ($L = 0.1L_{\rm Edd}$). 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 ($\sim\! 20\%$) can be important for the shortest continuum lags, and likely has a significant impact on the {\it u} and {\it U} bands owing to Balmer continuum emission., Comment: 26 pages, 10 figures, accepted to ApJ. For a brief video describing the main results of this paper, please see: https://www.youtube.com/watch?v=yaYtcDvIoP0&feature=youtu.be

Published
2015
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9. SPACE TELESCOPE AND OPTICAL REVERBERATION MAPPING PROJECT. IV. ANOMALOUS BEHAVIOR OF THE BROAD ULTRAVIOLET EMISSION LINES IN NGC 5548

Author

Goad, MR, Korista, KT, De Rosa, G, Kriss, GA, Edelson, R, Barth, AJ, Ferland, GJ, Kochanek, CS, Netzer, H, Peterson, BM, Bentz, MC, Bisogni, S, Crenshaw, DM, Denney, KD, Ely, J, Fausnaugh, MM, Grier, CJ, Gupta, A, Horne, KD, Kaastra, J, Pancoast, A, Pei, L, Pogge, RW, Skielboe, A, Starkey, D, Vestergaard, M, Zu, Y, Anderson, MD, Arévalo, P, Bazhaw, C, Borman, GA, Boroson, TA, Bottorff, MC, Brandt, WN, Breeveld, AA, Brewer, BJ, Cackett, EM, Carini, MT, Croxall, KV, Bontà, E Dalla, De Lorenzo-Cáceres, A, Dietrich, M, Efimova, NV, Evans, PA, Filippenko, AV, Flatland, K, Gehrels, N, Geier, S, Gelbord, JM, Gonzalez, L, Gorjian, V, Grupe, D, Hall, PB, Hicks, S, Horenstein, D, Hutchison, T, Im, M, Jensen, JJ, Joner, MD, Jones, J, Kaspi, S, Kelly, BC, Kennea, JA, Kim, M, Kim, SC, Klimanov, SA, Lee, JC, Leonard, DC, Lira, P, MacInnis, F, Manne-Nicholas, ER, Mathur, S, McHardy, IM, Montouri, C, Musso, R, Nazarov, SV, Norris, RP, Nousek, JA, Okhmat, DN, Papadakis, I, Parks, JR, Pott, J-U, Rafter, SE, Rix, H-W, Saylor, DA, Schimoia, JS, Schnülle, K, Sergeev, SG, Siegel, M, Spencer, M, Sung, H-I, Teems, KG, Treu, T, Turner, CS, Uttley, P, Villforth, C, Weiss, Y, Woo, J-H, Yan, H, and Young, S

Subjects
galaxies: active, galaxies: individual, galaxies: nuclei, galaxies: Seyfert, astro-ph.GA, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert 1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far UV continuum and broad emission line variations decorrelated for ∼60-70 days, starting ∼75 days after the first HST/COS observation. Following this anomalous state, the flux and variability of the broad emission lines returned to a more normal state. This transient behavior, characterized by significant deficits in flux and equivalent width of the strong broad UV emission lines, is the first of its kind to be unambiguously identified in an active galactic nucleus reverberation mapping campaign. The largest corresponding emission line flux deficits occurred for the high ionization, collisionally excited lines C iv and Si iv(+O iv]), and also He ii(+O iii]), while the anomaly in Lywas substantially smaller. This pattern of behavior indicates a depletion in the flux of photons with relative to those near 13.6 eV. We suggest two plausible mechanisms for the observed behavior: (i) temporary obscuration of the ionizing continuum incident upon broad line region (BLR) clouds by a moving veil of material lying between the inner accretion disk and inner (BLR), perhaps resulting from an episodic ejection of material from the disk, or (ii) a temporary change in the intrinsic ionizing continuum spectral energy distribution resulting in a deficit of ionizing photons with energies >54 eV, possibly due to a transient restructuring of the Comptonizing atmosphere above the disk. Current evidence appears to favor the latter explanation.

Published
2016

10. SPACE TELESCOPE AND OPTICAL REVERBERATION MAPPING PROJECT. III. OPTICAL CONTINUUM EMISSION AND BROADBAND TIME DELAYS IN NGC 5548

Author

Fausnaugh, MM, Denney, KD, Barth, AJ, Bentz, MC, Bottorff, MC, Carini, MT, Croxall, KV, De Rosa, G, Goad, MR, Horne, Keith, Joner, MD, Kaspi, S, Kim, M, Klimanov, SA, Kochanek, CS, Leonard, DC, Netzer, H, Peterson, BM, Schnülle, K, Sergeev, SG, Vestergaard, M, Zheng, W-K, Zu, Y, Anderson, MD, Arévalo, P, Bazhaw, C, Borman, GA, Boroson, TA, Brandt, WN, Breeveld, AA, Brewer, BJ, Cackett, EM, Crenshaw, DM, Bontà, E Dalla, 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, J-U, Rafter, SE, Rix, H-W, Saylor, DA, Schimoia, JS, Siegel, M, Spencer, M, Starkey, D, Sung, H-I, Teems, KG, Treu, T, Turner, CS, Uttley, P, Villforth, C, Weiss, Y, Woo, J-H, Yan, H, and Young, S

Subjects
galaxies: active, galaxies: individual, galaxies: nuclei, galaxies: Seyfert, astro-ph.GA, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
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 and λ1640 and λ4686), 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 τ ∝ λ 4 . 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 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.

Published
2016

11. Space Telescope and Optical Reverberation Mapping Project. VI. Reverberating Disk Models for NGS 5548

Author

Starkey, D, Gehrels, Cornelis, Horne, Keith, Fausnaugh, M. M, Peterson, B. M, Bentz, M. C, Kochanek, C. S, Denney, K. D, Edelson, R, Goad, M. R, De Rosa, G, Anderson, M. D, Arevalo, P, Barth, A. J, Bazhaw, C, Borman, G. A, Boroson, T. A, Bottorff, M. C, Brandt, W. N, Breeveld, A. A, Cackett E. M, Carini, M. T, Croxall, K. V, Crenshaw, D. M, Dalla Bonta, E, De Lorenzo-Caceres, A, Dietrich, M, Efimova, N. V, Ely, J, Evans, P. A, Filippenko, A. V, Flatland, I, 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, Joner, M. D, Jones, J, Kaastra, J, Kaspi, S, Kelly, B. C, Kennea, J. A, Kim, S. C, Kim, M, Kilmanov, S. A, Korista, K. T, Kriss, G. A, Lee, J. C, Leonard, D. 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, Parks, J. R, Pei, L, Pogge, R. W, Pott, J.-U, Rafter, S. E, Rix, H.-W, Saylor, D. A, Schimoia, J. S, Schnuelle, K, Sergeev, S. G, Siegel, M. H, Spencer, M, Sung, H. I, Teems, K. G, Turner, C. S, Uttley, P, Vestergaard, M, Villforth, C, Weiss, Y, Woo, J.-H, Yan, H, Young, S, Zheng, W, and Zu, Y

Subjects
Astrophysics
Abstract

We conduct a multi-wavelength continuum variability study of the Seyfert 1 galaxy NGC 5548 to investigate the temperature structure of its accretion disk. The 19 overlapping continuum light curves (1158 Angstrom to 9157 Angstrom) combine simultaneous Hubble Space Telescope, Swift, and ground-based observations over a 180 day period from 2014 January to July. Light-curve variability is interpreted as the reverberation response of the accretion disk to irradiation by a central time-varying point source. Our model yields the disk inclination i = 36deg +/- 10deg, temperature T(sub 1) = (44+/-6) times 10 (exp 3)K at 1 light day from the black hole, and a temperature radius slope (T proportional to r (exp -alpha)) of alpha = 0.99 +/- 0.03. We also infer the driving light curve and find that it correlates poorly with both the hard and soft X-ray light curves, suggesting that the X-rays alone may not drive the ultraviolet and optical variability over the observing period. We also decompose the light curves into bright, faint, and mean accretion-disk spectra. These spectra lie below that expected for a standard blackbody accretion disk accreting at L/L(sub Edd) = 0.1.

Published
2017
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12. SPACE TELESCOPE AND OPTICAL REVERBERATION MAPPING PROJECT. VI. REVERBERATING DISK MODELS FOR NGC 5548

Author

Starkey, D., Horne, Keith, Fausnaugh, M. M., Peterson, B. M., Bentz, M. C., Kochanek, C. S., Denney, K. D., Edelson, R., Goad, M. R., De Rosa, G., Anderson, M. D., Arevalo, P., Barth, A. J., Bazhaw, C., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Cackett, E. M., Carini, M. T., Croxall, K. V., Crenshaw, D. M., Dalla Bonta, E., De Lorenzo-Caceres, A., Dietrich, M., 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., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, S. C., Kim, M., Klimanov, S. A., Korista, K. T., Kriss, G. A., Lee, J. C., Leonard, D. 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., Parks, J. R., Pei, L., Pogge, R. W., Pott, J-U, Rafter, S. E., Rix, H-W, Saylor, D. A., Schimoia, J. S., Schnuelle, K., Sergeev, S. G., Siegel, M. H., Spencer, M., Sung, H-I, Teems, K. G., Turner, C. S., Uttley, P., Vestergaard, M., Villforth, C., Weiss, Y., Woo, J-H, Yan, H., Young, S., Zheng, W., Zu, Y., Starkey, D., Horne, Keith, Fausnaugh, M. M., Peterson, B. M., Bentz, M. C., Kochanek, C. S., Denney, K. D., Edelson, R., Goad, M. R., De Rosa, G., Anderson, M. D., Arevalo, P., Barth, A. J., Bazhaw, C., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Cackett, E. M., Carini, M. T., Croxall, K. V., Crenshaw, D. M., Dalla Bonta, E., De Lorenzo-Caceres, A., Dietrich, M., 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., Joner, M. D., Jones, J., Kaastra, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, S. C., Kim, M., Klimanov, S. A., Korista, K. T., Kriss, G. A., Lee, J. C., Leonard, D. 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., Parks, J. R., Pei, L., Pogge, R. W., Pott, J-U, Rafter, S. E., Rix, H-W, Saylor, D. A., Schimoia, J. S., Schnuelle, K., Sergeev, S. G., Siegel, M. H., Spencer, M., Sung, H-I, Teems, K. G., Turner, C. S., Uttley, P., Vestergaard, M., Villforth, C., Weiss, Y., Woo, J-H, Yan, H., Young, S., Zheng, W., and Zu, Y.

Published
2017

13. VizieR Online Data Catalog: Space telescope RM project. III. NGC 5548 LCs (Fausnaugh+, 2016)

Author

Fausnaugh, M. M., Denney, K. D., Barth, A. J., Bentz, M. C., Bottorff, M. C., Carini, M. T., Croxall, K. V., 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., Schnulle, K., Sergeev, S. G., Marianne Vestergaard, Zheng, W., Zu, Y., Anderson, M. D., Arevalo, 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 Bonta, E., Lorenzo-Caceres, 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., Saylor, D. A., Schimoia, J. S., Siegel, M., Spencer, M., Starkey, D., Sung, H., Teems, K. G., Treu, T., Turner, C. S., Uttley, P., Villforth, C., Weiss, Y., Woo, J., Yan, H., and Young, S.

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