The Astrophysical Journal (Jan 2024)
AGN STORM 2. X. The Origin of the Interband Continuum Delays in Mrk 817
- Hagai Netzer,
- Michael R. Goad,
- Aaron J. Barth,
- Edward M. Cackett,
- Keith Horne,
- Chen Hu,
- Erin Kara,
- Kirk T. Korista,
- Gerard A. Kriss,
- Collin Lewin,
- John Montano,
- Nahum Arav,
- Ehud Behar,
- Michael S. Brotherton,
- Doron Chelouche,
- Gisella De Rosa,
- Elena Dalla Bontà,
- Maryam Dehghanian,
- Gary J. Ferland,
- Carina Fian,
- Yasaman Homayouni,
- Dragana Ilić,
- Shai Kaspi,
- Andjelka B. Kovačević,
- Hermine Landt,
- Luka Č. Popović,
- Thaisa Storchi-Bergmann,
- Jian-Min Wang,
- Fatima Zaidouni
Affiliations
- Hagai Netzer
- ORCiD
- School of Physics and Astronomy, Tel Aviv University , Tel Aviv 6997801, Israel
- Michael R. Goad
- ORCiD
- School of Physics and Astronomy, University of Leicester , University Road, Leicester, LE1 7RH, UK
- Aaron J. Barth
- ORCiD
- Department of Physics and Astronomy, 4129 Frederick Reines Hall University of California , Irvine, CA 92697-4575, USA
- Edward M. Cackett
- ORCiD
- Department of Physics and Astronomy, Wayne State University , 666 W. Hancock Street, Detroit, MI 48201, USA
- Keith Horne
- ORCiD
- SUPA School of Physics and Astronomy , North Haugh, St. Andrews, KY16 9SS, Scotland, UK
- Chen Hu
- Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , 19B Yuquan Road, Beijing 100049, People's Republic of China
- Erin Kara
- ORCiD
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Kirk T. Korista
- ORCiD
- Department of Physics, Western Michigan University , 1120 Everett Tower, Kalamazoo, MI 49008-5252, USA
- Gerard A. Kriss
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Collin Lewin
- ORCiD
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- John Montano
- ORCiD
- Department of Physics and Astronomy, 4129 Frederick Reines Hall University of California , Irvine, CA 92697-4575, USA
- Nahum Arav
- ORCiD
- Department of Physics , Virginia Tech, Blacksburg, VA 24061, USA
- Ehud Behar
- ORCiD
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Department of Physics , Technion, Haifa 32000, Israel
- Michael S. Brotherton
- ORCiD
- Department of Physics and Astronomy, University of Wyoming , Laramie, WY 82071, USA
- Doron Chelouche
- Department of Physics, Faculty of Natural Sciences, University of Haifa , Haifa 3498838, Israel; Haifa Research Center for Theoretical Physics and Astrophysics, University of Haifa , Haifa 3498838, Israel
- Gisella De Rosa
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Elena Dalla Bontà
- ORCiD
- Dipartimento di Fisica e Astronomia “G. Galilei,” Università di Padova , Vicolo dell’Osservatorio 3, I-35122 Padova, Italy; INAF — Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122, Padova, Italy; Jeremiah Horrocks Institute, University of Central Lancashire , Preston, PR1 2HE, UK
- Maryam Dehghanian
- ORCiD
- Department of Physics , Virginia Tech, Blacksburg, VA 24061, USA
- Gary J. Ferland
- ORCiD
- Department of Physics and Astronomy, The University of Kentucky , Lexington, KY 40506, USA
- Carina Fian
- ORCiD
- Departamento de Astronomía y Astrofísica, Universidad de Valencia , E-46100 Burjassot, Valencia, Spain; Observatorio Astronómico, Universidad de Valencia , E-46980 Paterna, Valencia, Spain
- Yasaman Homayouni
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Astronomy and Astrophysics, The Pennsylvania State University , 525 Davey Laboratory, University Park, PA 16802, USA; Institute for Gravitation and the Cosmos, The Pennsylvania State University , University Park, PA 16802, USA
- Dragana Ilić
- ORCiD
- University of Belgrade—Faculty of Mathematics , Department of Astronomy, Studentski trg 16, 11000 Belgrade, Serbia; Hamburger Sternwarte, Universität Hamburg , Gojenbergsweg 112, 21029 Hamburg, Germany
- Shai Kaspi
- ORCiD
- School of Physics and Astronomy and Wise Observatory, Tel Aviv University , Tel Aviv 6997801, Israel
- Andjelka B. Kovačević
- ORCiD
- University of Belgrade—Faculty of Mathematics , Department of Astronomy, Studentski trg 16, 11000 Belgrade, Serbia
- Hermine Landt
- Centre for Extragalactic Astronomy, Department of Physics, Durham University , South Road, Durham, DH1 3LE, UK
- Luka Č. Popović
- ORCiD
- University of Belgrade—Faculty of Mathematics , Department of Astronomy, Studentski trg 16, 11000 Belgrade, Serbia; Astronomical Observatory , Volgina 7, 11060 Belgrade, Serbia
- Thaisa Storchi-Bergmann
- ORCiD
- Departamento de Astronomia—IF, Universidade Federal do Rio Grande do Sul , CP 150501, 91501-970 Porto Alegre, RS, Brazil
- Jian-Min Wang
- ORCiD
- Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , 19B Yuquan Road, Beijing 100049, People's Republic of China; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, People's Republic of China; National Astronomical Observatories of China , 20A Datun Road, Beijing 100020, People's Republic of China
- Fatima Zaidouni
- ORCiD
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- DOI
- https://doi.org/10.3847/1538-4357/ad8160
- Journal volume & issue
-
Vol. 976,
no. 1
p. 59
Abstract
The local ( z = 0.0315) active galactic nucleus (AGN) Mrk 817 was monitored over more than 500 days with space-borne and ground-based instruments as part of a large international campaign, AGN STORM 2. Here, we present a comprehensive analysis of the broadband continuum variations using detailed modeling of the broad line region (BLR), several types of disk winds classified by their optical depth, and new numerical simulations. We find that diffuse continuum (DC) emission, with additional contributions from strong and broad emission lines, can explain the continuum lags observed in this source during high- and low-luminosity phases. Disk illumination by the variable X-ray corona contributes only a small fraction of the observed continuum lags. Our BLR models assume radiation-pressure-confined clouds distributed over a distance of 2–122 light days. We present calculated mean emissivity radii of many emission lines, and DC emission, and suggest a simple, transfer-function-dependent method that ties them to cross-correlation lag determinations. We do not find clear indications for large-optical-depth winds, but identify the signature of lower-column-density winds. In particular, we associate the shortest observed continuum lags with a combination of τ (1 Ryd) ≈ 2 wind and a partly shielded BLR. Even smaller optical depth winds may be associated with X-ray absorption features and with noticeable variations in the widths and lags of several high-ionization lines like He ii and C iv . Finally, we demonstrate the effect of torus dust emission on the observed lags in the i and z bands.
Keywords
- Galaxy accretion disks
- Supermassive black holes
- Emission line galaxies
- Reverberation mapping
- Active galactic nuclei
