Probing Black Hole Accretion in Low Luminosity AGNs using ALMA Polarimetry
| Project/Area Number |
15K17619
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Astronomy
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| Research Institution | National Astronomical Observatory of Japan |
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Principal Investigator |
Nagai Hiroshi 国立天文台, アルマプロジェクト, 特任准教授 (00455198)
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| Research Collaborator |
Nakanishi Kouichiro
Fujita Yutaka
Asada Keiichi
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
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| Keywords | 活動銀河核 / ブラックホール降着流 / ALMA / VLBI / アルマ望遠鏡 / 偏波観測 / ブラックホール質量降着流 / 電波観測 / アルマ / 超巨大ブラックホール / 質量降着現象 / ミリ波サブミリ波偏波観測 |
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| Outline of Final Research Achievements |
Low-luminosity AGNs (LLAGNs) constitutes the largest population of AGNs in the nearby Universe, and thus the physical origin of those activities is quite important for the understanding of black hole accretion and its relation with the galaxy evolution in the present day of Universe. The polarization angle of the emission from AGNs is rotated as a passage through the accretion flow, so-called Faraday rotation effect. The measurement of Faraday rotation is a key method to constrain the accretion flow properties. We conducted ALMA and VLBI observations on the two nearby low luminosity AGNs. We found that the measured Faraday rotation is not consistent with the radiatively inefficient accretion flow (RIAF) model, which is the most favored model to explain the low luminosity. Alternatively, we propose that both RIAF and standard accretion disk co-exist or the accretion flow is highly inhomogeneous for these sources.
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| Academic Significance and Societal Importance of the Research Achievements |
ブラックホールの重力エネルギーを起源として光り輝く活動銀河核は、天体毎の明るさに大きなばらつきが見られる。明るさのばらつきは、ブラックホール近傍における物質の降着の仕方に起因していると考えられる。我々の観測結果は、従来考えられてきた理論的な描像では説明が難しく、ブラックホールへ物質が落ちる過程は想像以上に複雑であることを示唆している。
先日、ブラックホールシャドウ撮影の成功が報告されたことにより、ますますブラックホールへの関心が高まりつつある。本科研費による研究成果ならびに今後の発展によって、ブラックホール周辺の物理についての理解がますます進むと考えられる。
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Report
(5 results)
Research Products
(21 results)
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[Journal Article] ALMA Science Verification Data: Millimeter Continuum Polarimetry of the Bright Radio Quasar 3C 2862016
Author(s)
Nagai, H., Nakanishi, K., Paladino, R., Hull, C. L. H., Cortes, P., Moellenbrock, G., Fomalont, E., Asada, K., Hada, K.
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Journal Title
The Astrophysical Journal
Volume: 824
Issue: 2
Pages: 132-141
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Journal Article] Submillimeter Polarization Observation of the Protoplanetary Disk around HD 1425272016
Author(s)
Kataoka, A., Tsukagoshi, T., Momose, M., Nagai, H., Muto, T., Dullemond, C. P., Pohl, A., Fukagawa, M., Shibai, H., Hanawa, T., & Murakawa, K.
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Journal Title
The Astrophysical Journal Letters
Volume: 831
Issue: 2
Pages: 6-12
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
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[Journal Article] Nature of radio feature formed by re-started jet activity in 3C 84 and its relation with γ-ray emissions2016
Author(s)
Nagai, H., Chida, H., Kino, M., Orienti, M., D'Ammando, F., Giovannini, G., Hiura, K.
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Journal Title
Astronomische Nachrichten
Volume: 337
Issue: 1-2
Pages: 69-72
DOI
Related Report
Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
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[Journal Article] ALMA Science Verification Data: Millimeter Continuum Polarimetry of the Bright Radio Quasar 3C 2862016
Author(s)
Nagai, H., Nakanishi, K., Paladino, R., Hull, C. L. H., Cortes, P., Moellenbrock, G., Fomalont, E., Asada, K., Hada, K.
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Journal Title
Astrophysical Journal
Volume: 未定
Related Report
Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
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