Skip to content

Research at St Andrews

Space telescope and optical reverberation mapping project. X. Understanding the absorption-line holiday in NGC 5548

Research output: Contribution to journalArticle

Author(s)

M. Dehghanian, G. J. Ferland, G. A. Kriss, B. M. Peterson, S. Mathur, M. Mehdipour, F. Guzmán, M. Chatzikos, P. A. M. Van Hoof, R. J. R. Williams, N. Arav, A. J. Barth, M. C. Bentz, S. Bisogni, W. N. Brandt, D. M. Crenshaw, E. Dalla Bontà, G. De Rosa, M. M. Fausnaugh, J. M. Gelbord & 10 others M. R. Goad, A. Gupta, Keith Horne, J. Kaastra, C. Knigge, K. T. Korista, I. M. McHardy, R. W. Pogge, D. A. Starkey, M. Vestergaard

School/Research organisations

Abstract

The Space Telescope and Optical Reverberation Mapping Project (AGN STORM) on NGC 5548 in 2014 is one of the most intensive multiwavelength AGN monitoring campaigns ever. For most of the campaign, the emission-line variations followed changes in the continuum with a time lag, as expected. However, the lines varied independently of the observed UV-optical continuum during a 60–70 day "holiday," suggesting that unobserved changes to the ionizing continuum were present. To understand this remarkable phenomenon and to obtain an independent assessment of the ionizing continuum variations, we study the intrinsic absorption lines present in NGC 5548. We identify a novel cycle that reproduces the absorption line variability and thus identify the physics that allows the holiday to occur. In this cycle, variations in this obscurer's line-of-sight covering factor modify the soft X-ray continuum, changing the ionization of helium. Ionizing radiation produced by recombining helium then affects the level of ionization of some ions seen by the Hubble Space Telescope. In particular, high-ionization species are affected by changes in the obscurer covering factor, which does not affect the optical or UV continuum, and thus appear as uncorrelated changes, a "holiday." It is likely that any other model that selectively changes the soft X-ray part of the continuum during the holiday can also explain the anomalous emission-line behavior observed.
Close

Details

Original languageEnglish
Article number119
Number of pages10
JournalAstrophysical Journal
Volume877
Issue number2
Early online date3 Jun 2019
DOIs
Publication statusPublished - Jun 2019

    Research areas

  • Galaxies: active, Galaxies: individual (NGC 5548), Galaxies: nuclei, Galaxies: Seyfert, Line: formation

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. ROME/REA: a gravitational microlensing search for exoplanets beyond the snow line on a global network of robotic telescopes

    Tsapras, Y., Street, R. A., Hundertmark, M., Bachelet, E., Dominik, M., Bozza, V., Cassan, A., Wambsganss, J., Horne, K. D., Mao, S., Zang, W., Bramich, D. M. & Saha, A., 11 Oct 2019, In : Publications of the Astronomical Society of the Pacific. 131, 1006, p. 1-12 12 p., 1244401.

    Research output: Contribution to journalArticle

  2. Full orbital solution for the binary system in the Northern Galactic Disk microlensing event Gaia16aye

    Wyrzykowski, Ł., Mróz, P., Rybicki, K. A., Gromadzki, M., Kołaczkowski, Z., Zieliński, M., Zieliński, P., Britavskiy, N., Gomboc, A., Sokolovsky, K., Hodgkin, S. T., Abe, L., Aldi, G. F., AlMannaei, A., Altavilla, G., Qasim, A. A., Anupama, G. C., Awiphan, S., Bachelet, E., Bakis, V. & 152 others, Baker, S., Bartlett, S., Bendjoya, P., Benson, K., Bikmaev, I. F., Birenbaum, G., Blagorodnova, N., Blanco-Cuaresma, S., Boeva, S., Bonanos, A. Z., Bozza, V., Bramich, D. M., Bruni, I., Burenin, R. A., Burgaz, U., Butterley, T., Caines, H. E., Caton, D. B., Calchi Novati, S., Carrasco, J. M., Cassan, A., Čepas, V., Cropper, M., Chruślińska, M., Clementini, G., Clerici, A., Conti, D., Conti, M., Cross, S., Cusano, F., Damljanovic, G., Dapergolas, A., D'Ago, G., de Bruijne, J. H. J., Dennefeld, M., Dhillon, V. S., Dominik, M., Dziedzic, J., Erece, O., Eselevich, M. V., Esenoglu, H., Eyer, L., Figuera Jaimes, R., Fossey, S. J., Galeev, A. I., Grebenev, S. A., Gupta, A. C., Gutaev, A. G., Hallakoun, N., Hamanowicz, A., Han, C., Handzlik, B., Haislip, J. B., Hardy, L. K., Harrison, D. L., Hoette, V. L., Horne, K., Hudec, R., Hundertmark, M., Ihanec, N., Irtuganov, E. N., Itoh, R., Iwanek, P., Jovanovic, M. D., Janulis, R., Jelinek, M., Jensen, E., Kaczmarek, Z., Katz, D., Khamitov, I. M., Kilic, Y., Klencki, J., Kolb, U., Kouprianov, V. V., Kruszyńska, K., Kurowski, S., Latev, G., Lee, C-H., Leonini, S., Leto, G., Lewis, F., Li, Z., Liakos, A., Littlefair, S. P., Lu, J., Manser, C. J., Mao, S., Maoz, D., Maskoliunas, M., Maund, J. R., Melnikov, S. S., Ment, K., Mikołajczyk, P., Morrell, M., Mowlavi, N., Moździerski, D., Nazarov, S., Netzel, H., Nesci, R., Ngeow, C-C., Norton, A. J., Ofek, E. O., Pakstiene, E., Palaversa, L., Pandey, A., Paraskeva, E., Pawlak, M., Penny, M. T., Penprase, B. E., Piascik, A., Prieto, J. L., Qvam, J. K. T., Ranc, C., Rebassa-Mansergas, A., Reichart, D. E., Reig, P., Rhodes, L., Rivet, J-P., Rixon, G., Roberts, D., Rosi, P., Russell, D. M., Zanmar Sanchez, R., Scarpetta, G., Seabroke, G., Shappee, B. J., Schmidt, R., Shvartzvald, Y., Sitek, M., Skowron, J., Śniegowska, M., Snodgrass, C., Soares, P. S., Spetsieri, Z. T., Stankeviciute, A., Steele, I. A., Street, R. A., Strobl, J., Tinjaca Ramirez, L. M., Tomasella, L., Tsapras, Y., Villanueva, S. . J., Vince, O., Wambsganss, J., Wiersema, K., Wilson, R. W., Yoldas, A., Zhuchkov, R. Y., Zhukov, D. G., Zdanavicius, J., Zoła, S. & Zubareva, A., 11 Oct 2019, (Accepted/In press) In : Astronomy & Astrophysics.

    Research output: Contribution to journalArticle

  3. The first spectroscopic dust reverberation programme on active galactic nuclei: the torus in NGC 5548

    Landt, H., Ward, M. J., Kynoch, D., Packham, C., Ferland, G. J., Lawrence, A., Pott, J. -U., Esser, J., Horne, K., Starkey, D. A., Malhotra, D., Fausnaugh, M. M., Peterson, B. M., Wilman, R. J., Riffel, R. A., Storchi-Bergmann, T., Barth, A. J., Villforth, C. & Winkler, H., Oct 2019, In : Monthly Notices of the Royal Astronomical Society. 489, 2, p. 1572–1589

    Research output: Contribution to journalArticle

  4. Two new HATNet hot Jupiters around A stars, and the first glimpse at the occurrence rate of hot Jupiters from TESS*

    Zhou, G., Huang, C. X., Bakos, G. Á., Hartman, J. D., Latham, D. W., Quinn, S. N., Collins, K. A., Winn, J. N., Wong, I., Kovács, G., Csubry, Z., Bhatti, W., Penev, K., Bieryla, A., Esquerdo, G. A., Berlind, P., Calkins, M. L., de Val-Borro, M., Noyes, R. W., Lázár, J. & 51 others, Papp, I., Sári, P., Kovács, T., Buchhave, L. A., Szklenar, T., Béky, B., Johnson, M. C., Cochran, W. D., Kniazev, A. Y., Stassun, K. G., Fulton, B. J., Shporer, A., Espinoza, N., Bayliss, D., Everett, M., Howell, S. B., Hellier, C., Anderson, D. R., Cameron, A. C., West, R. G., Brown, D. J. A., Schanche, N., Barkaoui, K., Pozuelos, F., Gillon, M., Jehin, E., Benkhaldoun, Z., Daassou, A., Ricker, G., Vanderspek, R., Seager, S., Jenkins, J. M., Lissauer, J. J., Armstrong, J. D., Collins, K. I., Gan, T., Hart, R., Horne, K., Kielkopf, J. F., Nielsen, L. D., Nishiumi, T., Narita, N., Palle, E., Relles, H. M., Sefako, R., Tan, T. G., Davies, M., Goeke, R. F., Guerrero, N., Haworth, K. & Villanueva, S., Oct 2019, In : Astronomical Journal. 158, 4, p. 1-24 24 p., 141.

    Research output: Contribution to journalArticle

  5. OGLE-2015-BLG-1649Lb: a gas giant planet around a low-mass dwarf

    Nagakane, M., Lee, C-H., Koshimoto, N., Suzuki, D., Udalski, A., Beaulieu, J-P., Sumi, T., Bennett, D., Bond, I. A., Rattenbury, N. J., Bachelet, E., Dominik, M., Abe, F., Barry, R., Bhattacharya, A., Donachie, M., Fujii, H., Fukui, A., Hirao, Y., Itow, Y. & 49 others, Kamei, Y., Kondo, I., Li, M. C. A., Matsubara, Y., Matsuo, T., Miyazaki, S., Muraki, Y., Ranc, C., Shibai, H., Suematsu, H., Sullivan, D., Tristram, P., Yamakawa, T., Yonehara, A., Mróz, P., Poleski, R., Skowron, J., Szymański, M., Soszyński, I., Pietrukowicz, P., Kozłowski, S., Ulaczyk, K., Bramich, D., Cassan, A., Jaimes, R., Horne, K., Hundertmark, M., Mao, S., Menzies, J., Schmidt, R., Snodgrass, C., Steele, I., Street, R., Tsapras, Y., Wambsganss, J., Jørgensen, U., Bozza, V., Longã, P., Peixinho, N., Skottfelt, J., Southworth, J., Andersen, M. I., Burgdorf, M., D'Ago, G., Evans, D., Hinse, T., Korhonen, H., Rabus, M. & Rahvar, S., 25 Sep 2019, (Accepted/In press) In : Astronomical Journal.

    Research output: Contribution to journalArticle

Related by journal

  1. Astrophysical Journal (Journal)

    Carolin Villforth (Reviewer)
    2011 → …

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

  2. Astrophysical Journal (Journal)

    Christiane Helling (Reviewer)
    1 Jan 200631 Dec 2017

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

  3. Astrophysical Journal (Journal)

    Duncan Hendry Mackay (Editor)
    1997 → …

    Activity: Publication peer-review and editorial work typesEditor of research journal

  4. Astrophysical Journal (Journal)

    Alan William Hood (Editor)
    1980 → …

    Activity: Publication peer-review and editorial work typesEditor of research journal

Related by journal

  1. A cancellation nanoflare model for solar chromospheric and coronal heating. II. 2D theory and simulations

    Syntelis, P., Priest, E. R. & Chitta, L. P., 7 Feb 2019, In : Astrophysical Journal. 872, 1, 15 p., 32.

    Research output: Contribution to journalArticle

  2. A space weather tool for identifying eruptive active regions

    Pagano, P., Mackay, D. H. & Yardley, S. L., 9 Oct 2019, (Accepted/In press) In : Astrophysical Journal.

    Research output: Contribution to journalArticle

  3. Eruptions and flaring activity in emerging quadrupolar regions

    Syntelis, P., Lee, E. J., Fairbairn, C. W., Archontis, V. & Hood, A. W., 3 Sep 2019, (Accepted/In press) In : Astrophysical Journal.

    Research output: Contribution to journalArticle

  4. Estimating magnetic filling factors from Zeeman–Doppler magnetograms

    See, V., Matt, S. P., Folsom, C. P., Saikia, S. B., Donati, J-F., Fares, R., Finley, A. J., Hébrard, É. M., Jardine, M. M., Jeffers, S. V., Lehmann, L. T., Marsden, S. C., Mengel, M. W., Morin, J., Petit, P., Vidotto, A. A. & Waite, I. A., 9 May 2019, In : Astrophysical Journal. 876, 2, 118.

    Research output: Contribution to journalArticle

ID: 259378588

Top