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 outflowʼs column density variations throughout the campaign
Document Type
Article
Publication Date
2024
Digital Object Identifier (DOI)
https://doi.org/10.3847/1538-4357/ad6771
Funding Information
F.Z. and E.K. acknowledge support from NASA grant 80NSSC22K0570. P.K. acknowledges support from NASA through the NASA Hubble Fellowship grant HST-HF2- 51534.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. E.B. is grateful for the hospitality of MKI, where this collaborative work took place. Research at UC Irvine was supported by NSF grant AST-1907290. H.L. acknowledges a Daphne Jackson Fellowship sponsored by the Science and Technology Facilities Council (STFC), UK. M.C. B. gratefully acknowledges support from the NSF through grant AST-2009230. D.I., A.B.K and L.C.P. acknowledge funding provided by the University of Belgrade–Faculty of Mathematics (contract No. 451-03-47/2023-01/200104) and Astronomical Observatory Belgrade (contract No. 451-03-47/ 2023-01/200002) through the grants by the Ministry of Science, Technological Development and Innovation of the Republic of Serbia. D.I. acknowledges the support of the Alexander von Humboldt Foundation. A.B.K. and L.C.P. thank the support of the Chinese Academy of Sciences Presidentʼs International Fellowship Initiative (PIFI) for visiting scientists. C.S.K. is supported by NSF grant AST- 2307385. M.V. gratefully acknowledges financial support from the Independent Research Fund Denmark via grant No. DFF 8021-00130.
Repository Citation
Zaidouni, Fatima; Kara, Erin; Kosec, Peter; Mehdipour, Missagh; Rogantini, Daniele; Kriss, Gerard A.; Behar, Ehud; Kaastra, Jelle; Barth, Aaron J.; Cackett, Edward M.; De Rosa, Gisella; Homayouni, Yasaman; Horne, Keith; Landt, Hermine; Arav, Nahum; Bentz, Misty C.; Brotherton, Michael S.; Bontà, Elena Dalla; Dehghanian, Maryam; Ferland, Gary; Fian, Carina; Gelbord, Jonathan; Goad, Michael R.; González Buitrago, Diego H.; Grier, Catherine J.; Hall, Patrick B.; Hu, Chen; Ilić, Dragana; Kaspi, Shai; Kochanek, Christopher S.; Kovačević, Andjelka B.; Kynoch, Daniel; Lewin, Collin; Montano, John; Netzer, Hagai; Neustadt, Jack M. M.; Panagiotou, Christos; Partington, Ethan R.; Plesha, Rachel; Popović, Luka Č.; Proga, Daniel; Storchi-Bergmann, Thaisa; Sanmartim, David; Siebert, Matthew R.; Signorini, Matilde; Vestergaard, Marianne; Waters, Tim; and Zu, Ying, "AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy" (2024). Physics and Astronomy Faculty Publications. 684.
https://uknowledge.uky.edu/physastron_facpub/684
Notes/Citation Information
© 2024. The Author(s). Published by the American Astronomical Society