Swift Monitoring of NGC 4151

Evidence for a Second X-Ray/UV Reprocessing

R. Edelson, J. Gelbord, E. Cackett, S. Connolly, C. Done, M. Fausnaugh, E. Gardner, N. Gehrels, M. Goad, K. Horne, I. McHardy, B. M. Peterson, S. Vaughan, M. Vestergaard, A. Breeveld, A. J. Barth, M. Bentz, M. Bottorff, William Nielsen Brandt, S. M. Crawford & 24 others Elena Dalla Bontà, D. Emmanoulopoulos, P. Evans, R. Figuera Jaimes, A. V. Filippenko, G. Ferland, D. Grupe, M. Joner, Jamie A. Kennea, K. T. Korista, H. A. Krimm, G. Kriss, D. C. Leonard, S. Mathur, H. Netzer, John Andrew Nousek, K. Page, E. Romero-Colmenero, Michael Hiram Siegel, D. A. Starkey, T. Treu, H. A. Vogler, H. Winkler, W. Zheng

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Swift monitoring of NGC 4151 with an ∼6 hr sampling over a total of 69 days in early 2016 is used to construct light curves covering five bands in the X-rays (0.3-50 keV) and six in the ultraviolet (UV)/optical (1900-5500 Å). The three hardest X-ray bands (>2.5 keV) are all strongly correlated with no measurable interband lag, while the two softer bands show lower variability and weaker correlations. The UV/optical bands are significantly correlated with the X-rays, lagging ∼3-4 days behind the hard X-rays. The variability within the UV/optical bands is also strongly correlated, with the UV appearing to lead the optical by ∼0.5-1 days. This combination of ≳3 day lags between the X-rays and UV and ≲1 day lags within the UV/optical appears to rule out the "lamp-post" reprocessing model in which a hot, X-ray emitting corona directly illuminates the accretion disk, which then reprocesses the energy in the UV/optical. Instead, these results appear consistent with the Gardner & Done picture in which two separate reprocessings occur: first, emission from the corona illuminates an extreme-UV-emitting toroidal component that shields the disk from the corona; this then heats the extreme-UV component, which illuminates the disk and drives its variability.

Original languageEnglish (US)
Article number41
JournalAstrophysical Journal
Volume840
Issue number1
DOIs
StatePublished - May 1 2017

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monitoring
coronas
corona
x rays
time lag
accretion disks
light curve
luminaires
reprocessing
shield
coverings
sampling
accretion
heat
energy

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Edelson, R., Gelbord, J., Cackett, E., Connolly, S., Done, C., Fausnaugh, M., ... Zheng, W. (2017). Swift Monitoring of NGC 4151: Evidence for a Second X-Ray/UV Reprocessing. Astrophysical Journal, 840(1), [41]. https://doi.org/10.3847/1538-4357/aa6890
Edelson, R. ; Gelbord, J. ; Cackett, E. ; Connolly, S. ; Done, C. ; Fausnaugh, M. ; Gardner, E. ; Gehrels, N. ; Goad, M. ; Horne, K. ; McHardy, I. ; Peterson, B. M. ; Vaughan, S. ; Vestergaard, M. ; Breeveld, A. ; Barth, A. J. ; Bentz, M. ; Bottorff, M. ; Brandt, William Nielsen ; Crawford, S. M. ; Dalla Bontà, Elena ; Emmanoulopoulos, D. ; Evans, P. ; Jaimes, R. Figuera ; Filippenko, A. V. ; Ferland, G. ; Grupe, D. ; Joner, M. ; Kennea, Jamie A. ; Korista, K. T. ; Krimm, H. A. ; Kriss, G. ; Leonard, D. C. ; Mathur, S. ; Netzer, H. ; Nousek, John Andrew ; Page, K. ; Romero-Colmenero, E. ; Siegel, Michael Hiram ; Starkey, D. A. ; Treu, T. ; Vogler, H. A. ; Winkler, H. ; Zheng, W. / Swift Monitoring of NGC 4151 : Evidence for a Second X-Ray/UV Reprocessing. In: Astrophysical Journal. 2017 ; Vol. 840, No. 1.
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abstract = "Swift monitoring of NGC 4151 with an ∼6 hr sampling over a total of 69 days in early 2016 is used to construct light curves covering five bands in the X-rays (0.3-50 keV) and six in the ultraviolet (UV)/optical (1900-5500 {\AA}). The three hardest X-ray bands (>2.5 keV) are all strongly correlated with no measurable interband lag, while the two softer bands show lower variability and weaker correlations. The UV/optical bands are significantly correlated with the X-rays, lagging ∼3-4 days behind the hard X-rays. The variability within the UV/optical bands is also strongly correlated, with the UV appearing to lead the optical by ∼0.5-1 days. This combination of ≳3 day lags between the X-rays and UV and ≲1 day lags within the UV/optical appears to rule out the {"}lamp-post{"} reprocessing model in which a hot, X-ray emitting corona directly illuminates the accretion disk, which then reprocesses the energy in the UV/optical. Instead, these results appear consistent with the Gardner & Done picture in which two separate reprocessings occur: first, emission from the corona illuminates an extreme-UV-emitting toroidal component that shields the disk from the corona; this then heats the extreme-UV component, which illuminates the disk and drives its variability.",
author = "R. Edelson and J. Gelbord and E. Cackett and S. Connolly and C. Done and M. Fausnaugh and E. Gardner and N. Gehrels and M. Goad and K. Horne and I. McHardy and Peterson, {B. M.} and S. Vaughan and M. Vestergaard and A. Breeveld and Barth, {A. J.} and M. Bentz and M. Bottorff and Brandt, {William Nielsen} and Crawford, {S. M.} and {Dalla Bont{\`a}}, Elena and D. Emmanoulopoulos and P. Evans and Jaimes, {R. Figuera} and Filippenko, {A. V.} and G. Ferland and D. Grupe and M. Joner and Kennea, {Jamie A.} and Korista, {K. T.} and Krimm, {H. A.} and G. Kriss and Leonard, {D. C.} and S. Mathur and H. Netzer and Nousek, {John Andrew} and K. Page and E. Romero-Colmenero and Siegel, {Michael Hiram} and Starkey, {D. A.} and T. Treu and Vogler, {H. A.} and H. Winkler and W. Zheng",
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Edelson, R, Gelbord, J, Cackett, E, Connolly, S, Done, C, Fausnaugh, M, Gardner, E, Gehrels, N, Goad, M, Horne, K, McHardy, I, Peterson, BM, Vaughan, S, Vestergaard, M, Breeveld, A, Barth, AJ, Bentz, M, Bottorff, M, Brandt, WN, Crawford, SM, Dalla Bontà, E, Emmanoulopoulos, D, Evans, P, Jaimes, RF, Filippenko, AV, Ferland, G, Grupe, D, Joner, M, Kennea, JA, Korista, KT, Krimm, HA, Kriss, G, Leonard, DC, Mathur, S, Netzer, H, Nousek, JA, Page, K, Romero-Colmenero, E, Siegel, MH, Starkey, DA, Treu, T, Vogler, HA, Winkler, H & Zheng, W 2017, 'Swift Monitoring of NGC 4151: Evidence for a Second X-Ray/UV Reprocessing', Astrophysical Journal, vol. 840, no. 1, 41. https://doi.org/10.3847/1538-4357/aa6890

Swift Monitoring of NGC 4151 : Evidence for a Second X-Ray/UV Reprocessing. / Edelson, R.; Gelbord, J.; Cackett, E.; Connolly, S.; Done, C.; Fausnaugh, M.; Gardner, E.; Gehrels, N.; Goad, M.; Horne, K.; McHardy, I.; Peterson, B. M.; Vaughan, S.; Vestergaard, M.; Breeveld, A.; Barth, A. J.; Bentz, M.; Bottorff, M.; Brandt, William Nielsen; Crawford, S. M.; Dalla Bontà, Elena; Emmanoulopoulos, D.; Evans, P.; Jaimes, R. Figuera; Filippenko, A. V.; Ferland, G.; Grupe, D.; Joner, M.; Kennea, Jamie A.; Korista, K. T.; Krimm, H. A.; Kriss, G.; Leonard, D. C.; Mathur, S.; Netzer, H.; Nousek, John Andrew; Page, K.; Romero-Colmenero, E.; Siegel, Michael Hiram; Starkey, D. A.; Treu, T.; Vogler, H. A.; Winkler, H.; Zheng, W.

In: Astrophysical Journal, Vol. 840, No. 1, 41, 01.05.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Swift Monitoring of NGC 4151

T2 - Evidence for a Second X-Ray/UV Reprocessing

AU - Edelson, R.

AU - Gelbord, J.

AU - Cackett, E.

AU - Connolly, S.

AU - Done, C.

AU - Fausnaugh, M.

AU - Gardner, E.

AU - Gehrels, N.

AU - Goad, M.

AU - Horne, K.

AU - McHardy, I.

AU - Peterson, B. M.

AU - Vaughan, S.

AU - Vestergaard, M.

AU - Breeveld, A.

AU - Barth, A. J.

AU - Bentz, M.

AU - Bottorff, M.

AU - Brandt, William Nielsen

AU - Crawford, S. M.

AU - Dalla Bontà, Elena

AU - Emmanoulopoulos, D.

AU - Evans, P.

AU - Jaimes, R. Figuera

AU - Filippenko, A. V.

AU - Ferland, G.

AU - Grupe, D.

AU - Joner, M.

AU - Kennea, Jamie A.

AU - Korista, K. T.

AU - Krimm, H. A.

AU - Kriss, G.

AU - Leonard, D. C.

AU - Mathur, S.

AU - Netzer, H.

AU - Nousek, John Andrew

AU - Page, K.

AU - Romero-Colmenero, E.

AU - Siegel, Michael Hiram

AU - Starkey, D. A.

AU - Treu, T.

AU - Vogler, H. A.

AU - Winkler, H.

AU - Zheng, W.

PY - 2017/5/1

Y1 - 2017/5/1

N2 - Swift monitoring of NGC 4151 with an ∼6 hr sampling over a total of 69 days in early 2016 is used to construct light curves covering five bands in the X-rays (0.3-50 keV) and six in the ultraviolet (UV)/optical (1900-5500 Å). The three hardest X-ray bands (>2.5 keV) are all strongly correlated with no measurable interband lag, while the two softer bands show lower variability and weaker correlations. The UV/optical bands are significantly correlated with the X-rays, lagging ∼3-4 days behind the hard X-rays. The variability within the UV/optical bands is also strongly correlated, with the UV appearing to lead the optical by ∼0.5-1 days. This combination of ≳3 day lags between the X-rays and UV and ≲1 day lags within the UV/optical appears to rule out the "lamp-post" reprocessing model in which a hot, X-ray emitting corona directly illuminates the accretion disk, which then reprocesses the energy in the UV/optical. Instead, these results appear consistent with the Gardner & Done picture in which two separate reprocessings occur: first, emission from the corona illuminates an extreme-UV-emitting toroidal component that shields the disk from the corona; this then heats the extreme-UV component, which illuminates the disk and drives its variability.

AB - Swift monitoring of NGC 4151 with an ∼6 hr sampling over a total of 69 days in early 2016 is used to construct light curves covering five bands in the X-rays (0.3-50 keV) and six in the ultraviolet (UV)/optical (1900-5500 Å). The three hardest X-ray bands (>2.5 keV) are all strongly correlated with no measurable interband lag, while the two softer bands show lower variability and weaker correlations. The UV/optical bands are significantly correlated with the X-rays, lagging ∼3-4 days behind the hard X-rays. The variability within the UV/optical bands is also strongly correlated, with the UV appearing to lead the optical by ∼0.5-1 days. This combination of ≳3 day lags between the X-rays and UV and ≲1 day lags within the UV/optical appears to rule out the "lamp-post" reprocessing model in which a hot, X-ray emitting corona directly illuminates the accretion disk, which then reprocesses the energy in the UV/optical. Instead, these results appear consistent with the Gardner & Done picture in which two separate reprocessings occur: first, emission from the corona illuminates an extreme-UV-emitting toroidal component that shields the disk from the corona; this then heats the extreme-UV component, which illuminates the disk and drives its variability.

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Edelson R, Gelbord J, Cackett E, Connolly S, Done C, Fausnaugh M et al. Swift Monitoring of NGC 4151: Evidence for a Second X-Ray/UV Reprocessing. Astrophysical Journal. 2017 May 1;840(1). 41. https://doi.org/10.3847/1538-4357/aa6890