Space Telescope and Optical Reverberation Mapping Project. IV. Anomalous Behavior of the Broad Ultraviolet Emission Lines in NGC 5548
| Autor: | 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., Zheng, W. -K. |
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| Přispěvatelé: | High Energy Astrophys. & Astropart. Phys (API, FNWI), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, ITA, USA, GBR |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Active galactic nucleus
010504 meteorology & atmospheric sciences Cosmic Origins Spectrograph active [Galaxies] Astrophysics::High Energy Astrophysical Phenomena galaxies: active galaxies: individual (NGC-5548) galaxies: nuclei galaxies: Seyfert Supporting material: animation Continuum (design consultancy) Doubly ionized oxygen NDAS FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences 0103 physical sciences QB Astronomy Emission spectrum Seyfert Supporting material: animation [Galaxies] 010303 astronomy & astrophysics QC Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences QB Galáxia NGC 5548 Physics individual (NGC – 5548) [Galaxies] active galaxies: individual (NGC 5548) galaxies: nuclei galaxies: Seyfert [galaxies] Astronomy and Astrophysics Astrophysics - Astrophysics of Galaxies Galaxias seyfert Galaxy Galáxias ativas QC Physics Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) nuclei [Galaxies] individual (NGC-5548) [Galaxies] Reverberation mapping Equivalent width Nucleo galatico |
| Zdroj: | Astrophysical Journal, 824(1):11. IOP Publishing Ltd. ASTROPHYSICAL JOURNAL, 824, 11 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, 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, Dalla Bontà, E, De Lorenzo-Cáceres, 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 . https://doi.org/10.3847/0004-637X/824/1/11 Repositório Institucional da UFRGS Universidade Federal do Rio Grande do Sul (UFRGS) instacron:UFRGS |
| ISSN: | 0004-637X |
| DOI: | 10.3847/0004-637x/824/1/11 |
| Popis: | 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. 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 |
| Databáze: | OpenAIRE |
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