Radiatively Driven Clumpy X-Ray Absorbers in the NLS1 Galaxy IRAS 13224-3809
Recent radiation-magnetohydrodynamic simulations of active galactic nuclei predict the presence of the disk winds, which may become unstable and turn into fragmented clumps far from the central black hole. These inner winds and the outer clumps may be observed as ultrafast outflows (UFOs) and partia...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ace71a |
| _version_ | 1797697979086274560 |
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| author | Takuya Midooka Misaki Mizumoto Ken Ebisawa |
| author_facet | Takuya Midooka Misaki Mizumoto Ken Ebisawa |
| author_sort | Takuya Midooka |
| collection | DOAJ |
| description | Recent radiation-magnetohydrodynamic simulations of active galactic nuclei predict the presence of the disk winds, which may become unstable and turn into fragmented clumps far from the central black hole. These inner winds and the outer clumps may be observed as ultrafast outflows (UFOs) and partial absorbers, respectively. However, it is challenging to observationally constrain their origins because of the complicated spectral features and variations. To resolve such degeneracies of the clumpy absorbers and other components, we developed a novel spectral-ratio model fitting technique that estimates the variable absorbing parameters from the ratios of the partially absorbed spectra to the non-absorbed one, canceling the complex non-variable spectral features. We applied this method to the narrow-line Seyfert 1 galaxy IRAS 13224-3809 observed by XMM-Newton in 2016 for ∼1.5 Ms. As a result, we found that the soft spectral variation is mostly caused by changes in the partial covering fraction of the mildly ionized clumpy absorbers, whose outflow velocities are similar to those of the UFO (∼0.2–0.3 c ). Furthermore, the velocities of the clumpy absorbers and UFOs increase similarly with the X-ray fluxes, consistent with the change in the UV-dominant continuum flux. We also discovered a striking correlation between the clump covering fraction and the equivalent width of the UFO absorption lines, which indicates that increasing the outflow in the line of sight leads to more prominent UFOs and more partial absorption. These findings strongly suggest that the clumpy absorbers and the UFO share the same origin, driven by the same UV-dominant continuum radiation. |
| first_indexed | 2024-03-12T03:47:37Z |
| format | Article |
| id | doaj.art-8aee03e379f14d9b9e0d855a9563749f |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:47:37Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-8aee03e379f14d9b9e0d855a9563749f2023-09-03T12:36:59ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195414710.3847/1538-4357/ace71aRadiatively Driven Clumpy X-Ray Absorbers in the NLS1 Galaxy IRAS 13224-3809Takuya Midooka0https://orcid.org/0000-0002-6874-591XMisaki Mizumoto1https://orcid.org/0000-0003-2161-0361Ken Ebisawa2https://orcid.org/0000-0002-5352-7178Institute of Space and Astronautical Science , Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan midooka@ac.jaxa.jp; Department of Astronomy, Graduate School of Science, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654 JapanScience Education Research Unit, University of Teacher Education Fukuoka , 1-1 Akama-bunkyo-machi, Munakata, Fukuoka 811-4192, Japan mizumoto-m@fukuoka-edu.ac.jpInstitute of Space and Astronautical Science , Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan midooka@ac.jaxa.jp; Department of Astronomy, Graduate School of Science, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654 JapanRecent radiation-magnetohydrodynamic simulations of active galactic nuclei predict the presence of the disk winds, which may become unstable and turn into fragmented clumps far from the central black hole. These inner winds and the outer clumps may be observed as ultrafast outflows (UFOs) and partial absorbers, respectively. However, it is challenging to observationally constrain their origins because of the complicated spectral features and variations. To resolve such degeneracies of the clumpy absorbers and other components, we developed a novel spectral-ratio model fitting technique that estimates the variable absorbing parameters from the ratios of the partially absorbed spectra to the non-absorbed one, canceling the complex non-variable spectral features. We applied this method to the narrow-line Seyfert 1 galaxy IRAS 13224-3809 observed by XMM-Newton in 2016 for ∼1.5 Ms. As a result, we found that the soft spectral variation is mostly caused by changes in the partial covering fraction of the mildly ionized clumpy absorbers, whose outflow velocities are similar to those of the UFO (∼0.2–0.3 c ). Furthermore, the velocities of the clumpy absorbers and UFOs increase similarly with the X-ray fluxes, consistent with the change in the UV-dominant continuum flux. We also discovered a striking correlation between the clump covering fraction and the equivalent width of the UFO absorption lines, which indicates that increasing the outflow in the line of sight leads to more prominent UFOs and more partial absorption. These findings strongly suggest that the clumpy absorbers and the UFO share the same origin, driven by the same UV-dominant continuum radiation.https://doi.org/10.3847/1538-4357/ace71aActive galactic nucleiSeyfert galaxiesX-ray astronomy |
| spellingShingle | Takuya Midooka Misaki Mizumoto Ken Ebisawa Radiatively Driven Clumpy X-Ray Absorbers in the NLS1 Galaxy IRAS 13224-3809 The Astrophysical Journal Active galactic nuclei Seyfert galaxies X-ray astronomy |
| title | Radiatively Driven Clumpy X-Ray Absorbers in the NLS1 Galaxy IRAS 13224-3809 |
| title_full | Radiatively Driven Clumpy X-Ray Absorbers in the NLS1 Galaxy IRAS 13224-3809 |
| title_fullStr | Radiatively Driven Clumpy X-Ray Absorbers in the NLS1 Galaxy IRAS 13224-3809 |
| title_full_unstemmed | Radiatively Driven Clumpy X-Ray Absorbers in the NLS1 Galaxy IRAS 13224-3809 |
| title_short | Radiatively Driven Clumpy X-Ray Absorbers in the NLS1 Galaxy IRAS 13224-3809 |
| title_sort | radiatively driven clumpy x ray absorbers in the nls1 galaxy iras 13224 3809 |
| topic | Active galactic nuclei Seyfert galaxies X-ray astronomy |
| url | https://doi.org/10.3847/1538-4357/ace71a |
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