Jack M. M. Neustadt
AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817
Neustadt, Jack M. M.; Kochanek, Christopher S.; Montano, John; Gelbord, Jonathan; Barth, Aaron J.; De Rosa, Gisella; Kriss, Gerard A.; Cackett, Edward M.; Horne, Keith; Kara, Erin A.; Landt, Hermine; Netzer, Hagai; Arav, Nahum; Bentz, Misty C.; Dalla Bontà, Elena; Dehghanian, Maryam; Du, Pu; Edelson, Rick; Ferland, Gary J.; Fian, Carina; Fischer, Travis; Goad, Michael R.; González Buitrago, Diego H.; Gorjian, Varoujan; Grier, Catherine J.; Hall, Patrick B.; Homayouni, Y.; Hu, Chen; Ilić, Dragana; Joner, Michael D.; Kaastra, Jelle; Kaspi, Shai; Korista, Kirk T.; Kovačević, Andjelka B.; Lewin, Collin; Li, Yan-Rong; McHardy, Ian M.; Mehdipour, Missagh; Miller, Jake A.; Panagiotou, Christos; Partington, Ethan; Plesha, Rachel; Pogge, Richard W.; Popović, Luka Č.; Proga, Daniel; Storchi-Bergmann, Thaisa; Sanmartim, David; Siebert, Matthew R.; Signorini, Matilde; Vestergaard, Marianne; Zaidouni, Fatima; Zu, Ying
Authors
Christopher S. Kochanek
John Montano
Jonathan Gelbord
Aaron J. Barth
Gisella De Rosa
Gerard A. Kriss
Edward M. Cackett
Keith Horne
Erin A. Kara
Dr Hermine Landt-Wilman hermine.landt@durham.ac.uk
Academic Visitor
Hagai Netzer
Nahum Arav
Misty C. Bentz
Elena Dalla Bontà
Maryam Dehghanian
Pu Du
Rick Edelson
Gary J. Ferland
Carina Fian
Travis Fischer
Michael R. Goad
Diego H. González Buitrago
Varoujan Gorjian
Catherine J. Grier
Patrick B. Hall
Y. Homayouni
Chen Hu
Dragana Ilić
Michael D. Joner
Jelle Kaastra
Shai Kaspi
Kirk T. Korista
Andjelka B. Kovačević
Collin Lewin
Yan-Rong Li
Ian M. McHardy
Missagh Mehdipour
Jake A. Miller
Christos Panagiotou
Ethan Partington
Rachel Plesha
Richard W. Pogge
Luka Č. Popović
Daniel Proga
Thaisa Storchi-Bergmann
David Sanmartim
Matthew R. Siebert
Matilde Signorini
Marianne Vestergaard
Fatima Zaidouni
Ying Zu
Abstract
We fit the UV/optical lightcurves of the Seyfert 1 galaxy Mrk 817 to produce maps of the accretion disk temperature fluctuations δ T resolved in time and radius. The δ T maps are dominated by coherent radial structures that move slowly (v ≪ c) inward and outward, which conflicts with the idea that disk variability is driven only by reverberation. Instead, these slow-moving temperature fluctuations are likely due to variability intrinsic to the disk. We test how modifying the input lightcurves by smoothing and subtracting them changes the resulting δ T maps and find that most of the temperature fluctuations exist over relatively long timescales (hundreds of days). We show how detrending active galactic nucleus (AGN) lightcurves can be used to separate the flux variations driven by the slow-moving temperature fluctuations from those driven by reverberation. We also simulate contamination of the continuum emission from the disk by continuum emission from the broad-line region (BLR), which is expected to have spectral features localized in wavelength, such as the Balmer break contaminating the U band. We find that a disk with a smooth temperature profile cannot produce a signal localized in wavelength and that any BLR contamination should appear as residuals in our model lightcurves. Given the observed residuals, we estimate that only ∼20% of the variable flux in the U and u lightcurves can be due to BLR contamination. Finally, we discus how these maps not only describe the data but can make predictions about other aspects of AGN variability.
Citation
Neustadt, J. M. M., Kochanek, C. S., Montano, J., Gelbord, J., Barth, A. J., De Rosa, G., …Zu, Y. (2024). AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817. Astrophysical Journal, 961(2), Article 219. https://doi.org/10.3847/1538-4357/ad1386
Journal Article Type | Article |
---|---|
Acceptance Date | Dec 6, 2023 |
Online Publication Date | Jan 29, 2024 |
Publication Date | Feb 1, 2024 |
Deposit Date | Mar 19, 2024 |
Publicly Available Date | Mar 19, 2024 |
Journal | The Astrophysical Journal |
Print ISSN | 0004-637X |
Publisher | American Astronomical Society |
Peer Reviewed | Peer Reviewed |
Volume | 961 |
Issue | 2 |
Article Number | 219 |
DOI | https://doi.org/10.3847/1538-4357/ad1386 |
Public URL | https://durham-repository.worktribe.com/output/2192880 |
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Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
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