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1826193252822286336
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MIT
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<jats:title>Abstract</jats:title>
<jats:p>We present the first results from the ongoing, intensive, multiwavelength monitoring program of the luminous Seyfert 1 galaxy Mrk 817. While this active galactic nucleus was, in part, selected for its historically unobscured nature, we discovered that the X-ray spectrum is highly absorbed, and there are new blueshifted, broad, and narrow UV absorption lines, which suggest that a dust-free, ionized obscurer located at the inner broad-line region partially covers the central source. Despite the obscuration, we measure UV and optical continuum reverberation lags consistent with a centrally illuminated Shakura–Sunyaev thin accretion disk, and measure reverberation lags associated with the optical broad-line region, as expected. However, in the first 55 days of the campaign, when the obscuration was becoming most extreme, we observe a de-coupling of the UV continuum and the UV broad emission-line variability. The correlation recovered in the next 42 days of the campaign, as Mrk 817 entered a less obscured state. The short C <jats:sc>iv</jats:sc> and Ly<jats:italic>α</jats:italic> lags suggest that the accretion disk extends beyond the UV broad-line region.</jats:p>
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2024-09-23T09:36:00Z
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Article
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| id |
mit-1721.1/141970
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| institution |
Massachusetts Institute of Technology
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| language |
English
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2024-09-23T09:36:00Z
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2022
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American Astronomical Society
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dspace
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mit-1721.1/1419702022-04-21T03:36:47Z AGN STORM 2. I. First results: A Change in the Weather of Mrk 817 <jats:title>Abstract</jats:title> <jats:p>We present the first results from the ongoing, intensive, multiwavelength monitoring program of the luminous Seyfert 1 galaxy Mrk 817. While this active galactic nucleus was, in part, selected for its historically unobscured nature, we discovered that the X-ray spectrum is highly absorbed, and there are new blueshifted, broad, and narrow UV absorption lines, which suggest that a dust-free, ionized obscurer located at the inner broad-line region partially covers the central source. Despite the obscuration, we measure UV and optical continuum reverberation lags consistent with a centrally illuminated Shakura–Sunyaev thin accretion disk, and measure reverberation lags associated with the optical broad-line region, as expected. However, in the first 55 days of the campaign, when the obscuration was becoming most extreme, we observe a de-coupling of the UV continuum and the UV broad emission-line variability. The correlation recovered in the next 42 days of the campaign, as Mrk 817 entered a less obscured state. The short C <jats:sc>iv</jats:sc> and Ly<jats:italic>α</jats:italic> lags suggest that the accretion disk extends beyond the UV broad-line region.</jats:p> 2022-04-20T15:47:25Z 2022-04-20T15:47:25Z 2021 2022-04-20T15:43:22Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/141970 2021. "AGN STORM 2. I. First results: A Change in the Weather of Mrk 817." Astrophysical Journal, 922 (2). en 10.3847/1538-4357/AC2159 Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Astronomical Society The American Astronomical Society
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| spellingShingle |
AGN STORM 2. I. First results: A Change in the Weather of Mrk 817
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| title |
AGN STORM 2. I. First results: A Change in the Weather of Mrk 817
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| title_full |
AGN STORM 2. I. First results: A Change in the Weather of Mrk 817
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| title_fullStr |
AGN STORM 2. I. First results: A Change in the Weather of Mrk 817
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| title_full_unstemmed |
AGN STORM 2. I. First results: A Change in the Weather of Mrk 817
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| title_short |
AGN STORM 2. I. First results: A Change in the Weather of Mrk 817
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| title_sort |
agn storm 2 i first results a change in the weather of mrk 817
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| url |
https://hdl.handle.net/1721.1/141970
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