Institute of Astronomy, School of Science, University of Tokyo
Institute of Astronomy, School of Science, University of Tokyo
National Astronomical Observatory
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS)(JAXA)
National Astronomical Observatory
Institute of Astronomy, School of Science, University of Tokyo
Department of Astronomy, School of Science, University of Tokyo
Department of Astronomy, School of Science, University of Tokyo
Department of Astronomy, School of Science, University of Tokyo
Department of Astronomy, School of Science, University of Tokyo
出版者
宇宙航空研究開発機構
出版者（英）
Japan Aerospace Exploration Agency (JAXA)
雑誌名
宇宙航空研究開発機構特別資料
雑誌名(英)
JAXA Special Publication: Astrophysics with All-Sky X-Ray observations: 3rd International MAXI Workshop
巻
JAXA-SP-08-014E
ページ
218 - 222
発行年
2009-02-27
会議概要（会議名, 開催地, 会期, 主催者等）（英）
Astrophysics with All-Sky X-Ray observations: 3rd International MAXI Workshop (RIKEN, 10-12 June 2008)
抄録（英）
We carried out a one-night optical V and near-infrared JHK monitoring observation of the least luminous Seyfert 1 galaxy, NGC 4395, on 2004 May 1, and detected intraday flux variations in the V, J, and H bands. The near-infrared flux variations are almost synchronized with the flux variation in the V band. This indicates that the intraday-variable component of near-infrared continuum emission of the NGC 4395 nucleus is an extension of UV-optical power-law continuum emission and originates in an outer region of the central accretion disk. In addition, a possible time lag of ca. 7 minutes between the V-band and infrared flux variations was found by cross-correlation analysis. These results can be explained by the X-ray reprocessing model, in which X-ray flux variation propagates with light velocity and drives the flux variations in optical and near-infrared wavelengths. We also carried out the most intense monitoring observations in the optical and near-infrared wavebands for a Seyfert 1 galaxy, NGC 5548, and examined the correlation between the X-ray and optical flux variations. The X-ray light curve was taken from Uttley et al. (2003) as observed by the Rossi X-ray Timing Explorer (RXTE). The V-band flux variation shows a clear lag of 1 - 2 days behind the X-ray flux variation, which supports the X-ray reprocessing model for the optical flux variation at short timescales.
Near-infrared intraday variations in AGNs
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