The underlying driver behind the optical variability of AGN, and its link to theX-ray variability, is currently in dispute. Are the optical variations dominatedby reprocessing of X-ray photons (ie the optical lags), or by inwardlypropagating accretion rate fluctuations which alter the intrinsic thermalemission from the disc (ie the optical leads)? Current observations favouroptical lags there are no unambiguous examples. In NGC4395, a well known highlyvariable X-ray AGN, we have previously found a tentative 400s UV lag, atimescale well suited to observations with XMM. Here, with a combination of XMMand ground-based observations we aim to measure the lag accurately and henceshow whether optical variability in AGN is driven by disc variations or by X-ray reprocessing.
Publications
The origin of UV-optical variability in AGN and test of disc models: XMM-Newton and ground-based observations of NGC 4395 |McHardy, I. M., Connolly, S. D., et al. | AN | 337-500 | 2016 | 2016AN....337..500M | http://ui.adsabs.harvard.edu/#abs/2016AN....337..500M
The Nature of the Broadband X-Ray Variability in the Dwarf Seyfert Galaxy NGC 4395 |Kammoun, E. S., Nardini, E., et al. | ApJ | 886-145 | 2019 | 2019ApJ...886..145K | http://ui.adsabs.harvard.edu/#abs/2019ApJ...886..145K
Exploring the Link between the X-Ray Power Spectra and Energy Spectra of Active Galactic Nuclei |Yang, Haonan, Jin, Chichuan, | ApJ | 936-36 | 2022 | 2022ApJ...936...36Y | http://ui.adsabs.harvard.edu/#abs/2022ApJ...936...36Y
A Systematic Study of the Short-term X-Ray Variability of Seyfert Galaxies. I. Diversity of the X-Ray rms Spectra |Hu, Jingwei, Jin, Chichuan, et al. | ApJ | 936-105 | 2022 | 2022ApJ...936..105H | http://ui.adsabs.harvard.edu/#abs/2022ApJ...936..105H
X\\u2011HESS: A large sample of highly accreting serendipitous AGN under the XMM\\u2011Newton microscope |Laurenti, M., Tombesi, F., et al. | AN | 344-20230053 | 2023 | 2023AN....34430053L | http://ui.adsabs.harvard.edu/#abs/2023AN....34430053L
Investigating scaling relations in X-ray reverberating AGN using symbolic regression |Thongkonsing, P., Chainakun, P., et al. | MNRAS | 527-1950 | 2024 | 2024MNRAS.527.1950T | http://ui.adsabs.harvard.edu/#abs/2024MNRAS.527.1950T
The XMM-Newton Line Emission Analysis Program (X-LEAP). I. Emission-line Survey of O VII, O VIII, and Fe L-shell Transitions |Pan, Zeyang, Qu, Zhijie, et al. | ApJS | 271-62 | 2024 | 2024ApJS..271...62P | http://ui.adsabs.harvard.edu/#abs/2024ApJS..271...62P
Robust constraints on feebly interacting particles using XMM-Newton |Luque, Pedro De la Torre, Balaji, Shyam, | PhRvD | 109-L101305 | 2024 | 2024PhRvD.109j1305L | http://ui.adsabs.harvard.edu/#abs/2024PhRvD.109j1305L
Multimessenger search for electrophilic feebly interacting particles from supernovae |Luque, Pedro De la Torre, Balaji, Shyam, | PhRvD | 109-103028 | 2024 | 2024PhRvD.109j3028L | http://ui.adsabs.harvard.edu/#abs/2024PhRvD.109j3028L
Importance of Cosmic-Ray Propagation on Sub-GeV Dark Matter Constraints |De la Torre Luque, Pedro, Balaji, Shyam, | ApJ | 968-46 | 2024 | 2024ApJ...968...46D | http://ui.adsabs.harvard.edu/#abs/2024ApJ...968...46D
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2014-12-28T10:07:16Z/2014-12-31T00:41:44Z
Version
17.56_20190403_1200
Mission Description
The European Space Agencys (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESAs second cornerstone of the Horizon 2000 Science Programme. It carries 3 high throughput X-ray telescopes with an unprecedented effective area, and an optical monitor, the first flown on a X-ray observatory. The large collecting area and ability to make long uninterrupted exposures provide highly sensitive observations. Since Earths atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is being made available to the scientific community, applying for observational periods on a competitive basis.
European Space Agency, Prof Ian McHardy, 2016, 'THE ORIGIN OF OPTICAL VARIABILITY IN AGN: XMM AND GROUND OBSERVATIONS OF NGC4395', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-2ilgu1y
