AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy

Abstract We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multiwavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the AGN Space Telescope and Optical Reverberation Mapping 2 (AGN STORM 2) Project. The campaign revealed an unexpected and transient obscuring outflow, never before seen in this source. Of our four XMM-Newton/NuSTAR epochs, one fortuitously taken during a bright X-ray state has strong narrow absorption lines in the high-resolution grating spectra. From these absorption features, we determine that the obscurer is in fact a multiphase ionized wind with an outflow velocity of ∼5200 km s −1 , and for the first time find evidence for a lower ionization component with the same velocity observed in absorption features in the contemporaneous Hubble Space Telescope spectra. This indicates that the UV absorption troughs may be due to dense clumps embedded in diffuse, higher ionization gas responsible for the X-ray absorption lines of the same velocity. We observe variability in the shape of the absorption lines on timescales of hours, placing the variable component at roughly 1000 R g if attributed to transverse motion along the line of sight. This estimate aligns with independent UV measurements of the distance to the obscurer suggesting an accretion disk wind at the inner broad line region. We estimate that it takes roughly 200 days for the outflow to travel from the disk to our line of sight, consistent with the timescale of the outflow's column density variations throughout the campaign.

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Publication Details

Journal
The Astrophysical Journal
Published
2024-10-01
DOI
https://doi.org/10.3847/1538-4357/ad6771
Citations
7
Primary Topic
Astrophysical Phenomena and Observations
Type
article
Field-Weighted Citation Impact
2.32

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article

AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy

Maryam Dehghanian, Ehud Behar, J. S. Kaastra, Hermine Landt et al.
7 citations
The Astrophysical Journal
Astrophysical Phenomena and Observations
2.32
article

AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy

Maryam Dehghanian, Ehud Behar, J. S. Kaastra, Hermine Landt, Rachel Plesha, Luka Č. Popović, Erin Kara, J. M. Gelbord, Misty C. Bentz, Ethan R. Partington, Daniele Rogantini, Chen Hu, C. J. Grier, Aaron J. Barth, Ying Zu, Daniel Kynoch, Patrick B. Hall, M. Mehdipour, Edward M. Cackett, Matthew R. Siebert, M. R. Goad, D. González–Buitrago, Nahum Arav, C. S. Kochanek, S. Kaspi, Fatima Zaidouni, Matilde Signorini, Y. Homayouni, Daniel Proga, M. Vestergaard, David Sanmartim, G. J. Ferland, Peter Kosec, Collin Lewin, K. Horne, Christos Panagiotou, D. Ilić, M. S. Brotherton, Jack M. M. Neustadt, E. Dalla Bontà, C. Fian, Andjelka B. Kovačević, Gisella De Rosa, John Montano, H. Netzer, G. A. Kriss, Thaisa Storchi‐Bergmann, T.P. Waters
article en
7 citations

Abstract

Abstract We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multiwavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the AGN Space Telescope and Optical Reverberation Mapping 2 (AGN STORM 2) Project. The campaign revealed an unexpected and transient obscuring outflow, never before seen in this source. Of our four XMM-Newton/NuSTAR epochs, one fortuitously taken during a bright X-ray state has strong narrow absorption lines in the high-resolution grating spectra. From these absorption features, we determine that the obscurer is in fact a multiphase ionized wind with an outflow velocity of ∼5200 km s −1 , and for the first time find evidence for a lower ionization component with the same velocity observed in absorption features in the contemporaneous Hubble Space Telescope spectra. This indicates that the UV absorption troughs may be due to dense clumps embedded in diffuse, higher ionization gas responsible for the X-ray absorption lines of the same velocity. We observe variability in the shape of the absorption lines on timescales of hours, placing the variable component at roughly 1000 R g if attributed to transverse motion along the line of sight. This estimate aligns with independent UV measurements of the distance to the obscurer suggesting an accretion disk wind at the inner broad line region. We estimate that it takes roughly 200 days for the outflow to travel from the disk to our line of sight, consistent with the timescale of the outflow's column density variations throughout the campaign.

The Astrophysical JournalVol. 974(1)
Leiden University (NL), University of Copenhagen (DK), University of Wyoming (US), Space Telescope Science Institute (US), Universidade Federal do Rio Grande do Sul (BR), Pennsylvania State University (US), University of Nevada, Las Vegas (US), University of Wisconsin–Madison (US), University of Arizona (US), University of Padua (IT), University of Kentucky (US), University of Leicester (GB), Universität Hamburg (DE), Universitat de València (ES), University of California, Los Angeles (US), Tel Aviv University (IL), University of St Andrews (GB), Technion – Israel Institute of Technology (IL), Spectral Sciences (United States) (US), Georgia State University (US), Shanghai Jiao Tong University (CN), University of California, Santa Cruz (US), Wayne State University (US), Durham University (GB), York University (CA), Chinese Academy of Sciences (CN), University of California, Irvine (US), Arcetri Astrophysical Observatory (IT), Czech Academy of Sciences, Astronomical Institute (CZ), Parc Científic de la Universitat de València (ES), University of Belgrade (RS), Université Bourgogne Franche-Comté (FR), Institute of High Energy Physics (CN), Astronomical Observatory (RS), Osservatorio Astronomico di Padova (IT), University of Southampton (GB), University of Florence (IT), Space Research Organisation Netherlands (NL), The Ohio State University (US), Massachusetts Institute of Technology (US), Virginia Tech (US), Universidad Nacional Autónoma de México (MX)
National Science Foundation, National Aeronautics and Space Administration, Alexander von Humboldt-Stiftung, Space Telescope Science Institute, Chinese Academy of Sciences, Nuclear Safety and Security Commission, University of California, Irvine, Science and Technology Facilities Council, Astrophysics Science Division
Openalex Percentile: Top 12%
Astrophysical Phenomena and Observations
2.32
DOIOpen Access PDFOpenAlex
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