151. Swift monitoring of NGC 4151 : evidence for a second X-ray/UV reprocessing
- Author
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W. N. Brandt, K. L. Page, Misty C. Bentz, Encarni Romero-Colmenero, Dimitrios Emmanoulopoulos, Michael D. Joner, Steven M. Crawford, Hans A. Krimm, Gerard A. Kriss, H. A. Vogler, Tommaso Treu, S. Connolly, Marianne Vestergaard, Kirk T. Korista, J. A. Kennea, Aaron J. Barth, Phil Evans, WeiKang Zheng, Keith Horne, M. H. Siegel, M. R. Goad, Ian M. McHardy, A. A. Breeveld, Hagai Netzer, Alexei V. Filippenko, Chris Done, Simon Vaughan, E. Dalla Bontà, M. C. Bottorff, Dirk Grupe, Edward M. Cackett, Neil Gehrels, Hartmut Winkler, B. M. Peterson, Smita Mathur, Jonathan Gelbord, Michael Fausnaugh, Rick Edelson, Emma Gardner, D. A. Starkey, R. Figuera Jaimes, Gary J. Ferland, D. C. Leonard, J. A. Nousek, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
- Subjects
Seyfert [Galaxies] ,galaxies: active ,galaxies: individual (NGC 4151) ,galaxies: nuclei ,galaxies: Seyfert ,active [Galaxies] ,FOS: Physical sciences ,Astrophysics ,medicine.disease_cause ,01 natural sciences ,individual (NGC 4151) [Galaxies] ,Accretion disc ,0103 physical sciences ,medicine ,QB Astronomy ,010303 astronomy & astrophysics ,QC ,QB ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,010308 nuclear & particles physics ,X-ray ,Astronomy and Astrophysics ,3rd-DAS ,Light curve ,Corona ,QC Physics ,Space and Planetary Science ,nuclei [Galaxies] ,Astrophysics - High Energy Astrophysical Phenomena ,Ultraviolet - Abstract
Swift monitoring of NGC 4151 with ~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 A). 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 day. This combination of >~3 day lags between the X-rays and UV and, Comment: 14 pages, 6 figures, 7 tables. To appear in ApJ April 2017 issue. This version incorporates minor revisions to conform to published version and corrects the links to the author names above
- Published
- 2017