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dc.contributor.authorGoad, M. R.
dc.contributor.authorKorista, K. T.
dc.contributor.authorRosa, G. De
dc.contributor.authorKriss, G. A.
dc.contributor.authorEdelson, R.
dc.contributor.authorBarth, A. J.
dc.contributor.authorFerland, G. J.
dc.contributor.authorKochanek, C. S.
dc.contributor.authorNetzer, H.
dc.contributor.authorPeterson, B. M.
dc.contributor.authorBentz, M. C.
dc.contributor.authorBisogni, S.
dc.contributor.authorCrenshaw, D. M.
dc.contributor.authorDenney, K. D.
dc.contributor.authorEly, J.
dc.contributor.authorFausnaugh, M. M.
dc.contributor.authorGrier, C. J.
dc.contributor.authorGupta, A.
dc.contributor.authorHorne, K. D.
dc.contributor.authorKaastra, J.
dc.contributor.authorPancoast, A.
dc.contributor.authorPei, L.
dc.contributor.authorPogge, R. W.
dc.contributor.authorSkielboe, A.
dc.contributor.authorStarkey, D.
dc.contributor.authorVestergaard, M.
dc.contributor.authorZu, Y.
dc.contributor.authorAnderson, M. D.
dc.contributor.authorArévalo, P.
dc.contributor.authorBazhaw, C.
dc.contributor.authorBorman, G. A.
dc.contributor.authorBoroson, T. A.
dc.contributor.authorBottorff, M. C.
dc.contributor.authorBrandt, W. N.
dc.contributor.authorBreeveld, A. A.
dc.contributor.authorBrewer, B. J.
dc.contributor.authorCackett, E. M.
dc.contributor.authorCarini, M. T.
dc.contributor.authorCroxall, K. V.
dc.contributor.authorBontá, E. Dalla
dc.contributor.authorDe Lorenzo-Caceres Rodriguez, Adriana
dc.contributor.authorDietrich, M.
dc.contributor.authorEfimova, N. V.
dc.contributor.authorEvans, P. A.
dc.contributor.authorFilippenko, A. V.
dc.contributor.authorFlatland, K.
dc.contributor.authorGehrels, N.
dc.contributor.authorGeier, S.
dc.contributor.authorGelbord, J. M.
dc.contributor.authorGonzalez, L.
dc.contributor.authorGorjian, V.
dc.contributor.authorGrupe, D.
dc.contributor.authorHall, P. B.
dc.contributor.authorHicks, S.
dc.contributor.authorHorenstein, D.
dc.contributor.authorHutchison, T.
dc.contributor.authorIm, M.
dc.contributor.authorJensen, J. J.
dc.contributor.authorJoner, M. D.
dc.contributor.authorJones, J.
dc.contributor.authorKaspi, S.
dc.contributor.authorKelly, B. C.
dc.contributor.authorKennea, J. A.
dc.contributor.authorKim, M.
dc.contributor.authorKim, S. C.
dc.contributor.authorKlimanov, S. A.
dc.contributor.authorLee, J. C.
dc.contributor.authorLeonard, D. C.
dc.contributor.authorLira, P.
dc.contributor.authorMacinnis, F.
dc.contributor.authorManne-Nicholas, E. R.
dc.contributor.authorMathur, S.
dc.contributor.authorMcHardy, I. M.
dc.contributor.authorMontouri, C.
dc.contributor.authorMusso, R.
dc.contributor.authorNazarov, S. V.
dc.contributor.authorNorris, R. P.
dc.contributor.authorNousek, J. A.
dc.contributor.authorOkhmat, D. N.
dc.contributor.authorPapadakis, I.
dc.contributor.authorParks, J. R.
dc.contributor.authorPott, J. U.
dc.contributor.authorRafter, S. E.
dc.contributor.authorRix, H. W.
dc.contributor.authorSaylor, D. A.
dc.contributor.authorSchimoia, J. S.
dc.contributor.authorSchnülle, K.
dc.contributor.authorSergeev, S. G.
dc.contributor.authorSiegel, M.
dc.contributor.authorSpencer, M.
dc.contributor.authorSung, H. I.
dc.contributor.authorTeems, K. G.
dc.contributor.authorTreu, T.
dc.contributor.authorTurner, C. S.
dc.contributor.authorUttley, P.
dc.contributor.authorVillforth, C.
dc.contributor.authorWeiss, Y.
dc.contributor.authorWoo, J. H.
dc.contributor.authorYan, H.
dc.contributor.authorYoung, S.
dc.contributor.authorZheng, W. K.
dc.identifier.citationGoad , M R , Korista , K T , Rosa , G D , 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 , Arévalo , 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 , Bontá , E D , De Lorenzo-Caceres Rodriguez , A , Dietrich , M , Efimova , N V , Evans , P A , Filippenko , A V , Flatland , K , Gehrels , N , Geier , S , Gelbord , J 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 , 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 , Schnülle , 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 & Zheng , W K 2016 , ' Space telescope and optical reverberation mapping project. IV. Anomalous behavior of the broad ultraviolet emission lines in NGC 5548 ' , Astrophysical Journal , vol. 824 , no. 1 , 11 .
dc.identifier.otherPURE: 244399268
dc.identifier.otherPURE UUID: 0b30c222-d9c9-4519-8365-7f5ae70209b7
dc.identifier.otherScopus: 84976519790
dc.identifier.otherWOS: 000377937300011
dc.description.abstractDuring 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 Eph > 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 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.
dc.relation.ispartofAstrophysical Journalen
dc.rights© 2016. The American Astronomical Society. All rights reserved. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at:
dc.subjectGalaxies: activeen
dc.subjectGalaxies: individual (NGC-5548)en
dc.subjectGalaxies: nucleien
dc.subjectGalaxies: Seyfert Supporting material: animationen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.subjectSpace and Planetary Scienceen
dc.subjectAstronomy and Astrophysicsen
dc.titleSpace telescope and optical reverberation mapping project. IV. Anomalous behavior of the broad ultraviolet emission lines in NGC 5548en
dc.typeJournal articleen
dc.contributor.sponsorScience & Technology Facilities Councilen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.description.statusPeer revieweden

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