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相关论文: Could the inter-band lag of active galactic nucleu…

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Interband lags in the optical continua of active galactic nuclei (AGN) have been observed over years of monitoring, yet their physical origins remain unclear. While variable interband lags have been found in a few individual AGN…

星系天体物理 · 物理学 2025-07-08 Zhen-Bo Su , Zhen-Yi Cai , Hengxiao Guo , Mouyuan Sun , Jun-Xian Wang

Information on the structure around active galactic nuclei (AGN) has long been derived from measuring lags in their varying light output at different wavelengths. In principle, infrared data would reach to larger radii, potentially even…

星系天体物理 · 物理学 2021-03-17 E. Elmer , M. Merrifield , O. Almaini , W. G. Hartley , D. T. Maltby

The tight inter-band correlation and the lag-wavelength relation among UV/optical continua of active galactic nuclei have been firmly established. They are usually understood within the widespread reprocessing scenario, however, the implied…

高能天体物理现象 · 物理学 2018-03-16 Zhen-Yi Cai , Jun-Xian Wang , Fei-Fan Zhu , Mou-Yuan Sun , Wei-Min Gu , Xin-Wu Cao , Feng Yuan

Inconsistent conclusions are obtained from recent active galactic nuclei (AGNs) accretion disk inter-band time-lag measurements. While some works show that the measured time lags are significantly larger (by a factor of $\sim 3$) than the…

Number of monitoring observations of continuum emission from Active Galactic Nuclei (AGNs) have been made in optical--X-ray bands. The results obtained so far show (i) random up and down on timescales longer than decades, (ii) no typical…

天体物理学 · 物理学 2007-05-23 T. Kawaguchi , S. Mineshige

High cadence, high quality observations of active galactic nuclei (AGN) clearly show continuum variations with lags, relative to the shortest observed variable UV continuum, that increase with wavelength ("lag spectra"). These have been…

星系天体物理 · 物理学 2021-11-17 Hagai Netzer

Disk continuum reverberation mapping is one of the primary ways we learn about active galactic nuclei (AGN) accretion disks. Reverberation mapping assumes that time-varying X-rays incident on the accretion disk drive variability in…

高能天体物理现象 · 物理学 2025-01-14 Amy Secunda , Yan-Fei Jiang , Jenny E. Greene

Variable continuum emission from AGN can be used to probe the structure of their accretion disks via reverberation mapping. Assuming a variable, hot inner light source irradiates the surrounding accretion disk, time delays between different…

Over the last years, a number of broadband reverberation mapping campaigns have been conducted to explore the short-term UV and optical variability of nearby AGN. Despite the extensive data collected, the origin of the observed variability…

The variability of active galactic nuclei (AGN) has long held the promise of shedding light on their detailed structure, and possibly other astrophysical phenonema. Different emission mechanisms lead to different patterns of variability in…

天体物理学 · 物理学 2009-11-07 M. R. S. Hawkins

Magnetohydrodynamics (MHD) turbulence can drive significant temperature fluctuations in the accretion disk of an active galactic nucleus (AGN). As a result, the disk can be highly inhomogeneous and has a half-light radius larger than the…

高能天体物理现象 · 物理学 2024-04-15 Guowei Ren , Mouyuan Sun , Jun-Xian Wang , Zhen-Yi Cai

We present results of recurrence analysis of 46 active galactic nuclei (AGN) using light curves from the 157-month catalog of the Swift Burst Alert Telescope (BAT) in the 14-150 keV band. We generate recurrence plots and compute recurrence…

高能天体物理现象 · 物理学 2022-11-28 R. A. Phillipson , M. S. Vogeley , P. T. Boyd

Variability studies hold information on otherwise unresolvable regions in Active Galactic Nuclei (AGN). Population studies of large samples likewise have been very productive for our understanding of AGN. These two themes are coming…

高能天体物理现象 · 物理学 2016-05-31 Andy Lawrence

Continuum and emission-line variability of active galactic nuclei provides a powerful probe of microarcsecond scale structures in the central regions of these sources. In this contribution, we review basic concepts and methodologies used in…

天体物理学 · 物理学 2016-11-03 Bradley M. Peterson

The variability of active galactic nuclei (AGNs) is ubiquitous but has not yet been understood. Measuring the optical variation properties of AGNs, such as variation timescale and amplitude, and then correlating them with their fundamental…

星系天体物理 · 物理学 2024-01-11 Xu-Fan Hu , Zhen-Yi Cai , Jun-Xian Wang

Active Galactic Nuclei (AGN) are believed to be powered by accretion of matter onto a supermassive black hole. A fundamental ingredient in shaping our understanding of AGN is their variability across the entire electromagnetic spectrum.…

高能天体物理现象 · 物理学 2025-09-08 Maurizio Paolillo , Iossif Papadakis

Variability of active galactic nuclei (AGNs) has long been servicing as an essential avenue of exploring the accretion physics of black hole (BH). There are two commonly used methods for analyzing AGN variability. First, the AGN…

星系天体物理 · 物理学 2024-07-04 Zhen-Bo Su , Zhen-Yi Cai , Mouyuan Sun , Hengxiao Guo , Wei-Min Gu , Jun-Xian Wang

Observations and theoretical simulations suggest that the large scale environment plays a significant role in how galaxies form and evolve and, in particular, whether and when galaxies host an actively accreting supermassive black hole in…

星系天体物理 · 物理学 2025-07-16 Anish S. Aradhey , Anca Constantin , Michael S. Vogeley , Kelly A. Douglass

Many AGN exhibit a highly variable luminosity. Some AGN also show a pronounced time delay between variations seen in their optical continuum and in their emission lines. In effect, the emission lines are light echoes of the continuum. This…

天体物理学 · 物理学 2009-10-31 W. F. Welsh

The main fuelling processes for Active Galactic Nuclei (AGN) are currently unknown. Previous work showed that galaxies with a large kinematic misalignment between their stellar and gas reservoirs have a higher AGN fraction than galaxies…

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