Outputs (6)

What drives the variability in AGN? Explaining the UV-Xray disconnect through propagating fluctuations (2024)
Journal Article
Hagen, S., Done, C., & Edelson, R. (2024). What drives the variability in AGN? Explaining the UV-Xray disconnect through propagating fluctuations. Monthly Notices of the Royal Astronomical Society, 530(4), 4850-4867. https://doi.org/10.1093/mnras/stae1177

Intensive broad-band reverberation mapping campaigns have shown that AGN variability is significantly more complex than expected from disc reverberation of the variable X-ray illumination. The UV/optical variability is highly correlated and lagged, w... Read More about What drives the variability in AGN? Explaining the UV-Xray disconnect through propagating fluctuations.

The Peculiar Bursting Nature of CP Pup (2024)
Journal Article
Veresvarska, M., Scaringi, S., Hagen, S., De Martino, D., Done, C., Ilkiewicz, K., …Littlefield, C. (2024). The Peculiar Bursting Nature of CP Pup. Monthly Notices of the Royal Astronomical Society, 529(1), 664-672. https://doi.org/10.1093/mnras/stae573

The classical nova CP Puppis has been observed to have particularly puzzling and peculiar properties. In particular, this classical nova displays occasional bursts in its long-term ASAS-SN light curve. Here, we report on five sectors of TESS data dis... Read More about The Peculiar Bursting Nature of CP Pup.

Probing the face-on disc-corona system of the bare AGN Mrk 110 from UV to hard X-rays: A moderate changing-state AGN? (2024)
Journal Article
Porquet, D., Hagen, S., Grosso, N., Lobban, A., Reeves, J. N., Braito, V., & Done, C. (2024). Probing the face-on disc-corona system of the bare AGN Mrk 110 from UV to hard X-rays: A moderate changing-state AGN?. Astronomy & Astrophysics, 681, Article A40. https://doi.org/10.1051/0004-6361/202347202

Context. The X-ray broadband spectra of the bare active galactic nucleus (AGN) Mrk 110, obtained by simultaneous XMM-Newton and NuSTAR observations performed in November 2019 and April 2020, are characterised by the presence of a prominent and absorp... Read More about Probing the face-on disc-corona system of the bare AGN Mrk 110 from UV to hard X-rays: A moderate changing-state AGN?.

Estimating black hole spin from AGN SED fitting: the impact of general-relativistic ray tracing (2023)
Journal Article
Hagen, S., & Done, C. (2023). Estimating black hole spin from AGN SED fitting: the impact of general-relativistic ray tracing. Monthly Notices of the Royal Astronomical Society, 525(3), 3455-3467. https://doi.org/10.1093/mnras/stad2499

Accretion disc model fitting to optical/UV quasar spectra requires that the highest mass black holes have the highest spin, with implications on the hierarchical growth of supermassive black holes and their host galaxies over cosmic time. However, th... Read More about Estimating black hole spin from AGN SED fitting: the impact of general-relativistic ray tracing.

The SOUX AGN sample: optical/UV/X-ray SEDs and the nature of the disc (2023)
Journal Article
Mitchell, J. A. J., Done, C., Ward, M. J., Kynoch, D., Hagen, S., Lusso, E., & Landt, H. (2023). The SOUX AGN sample: optical/UV/X-ray SEDs and the nature of the disc. Monthly Notices of the Royal Astronomical Society, 524(2), 1796-1825. https://doi.org/10.1093/mnras/stad1830

We use the SOUX sample of ∼700 active galactic nucleus (AGN) to form average optical-ultraviolet (UV)-X-rays spectral energy distributions (SEDs) on a two-dimensional (2D) grid of MBH and L2500. We compare these with the predictions of a new AGN SED... Read More about The SOUX AGN sample: optical/UV/X-ray SEDs and the nature of the disc.

Modelling continuum reverberation in active galactic nuclei: a spectral-timing analysis of the ultraviolet variability through X-ray reverberation in Fairall 9 (2023)
Journal Article
Hagen, S., & Done, C. (2023). Modelling continuum reverberation in active galactic nuclei: a spectral-timing analysis of the ultraviolet variability through X-ray reverberation in Fairall 9. Monthly Notices of the Royal Astronomical Society, 521(1), 251-268. https://doi.org/10.1093/mnras/stad504

Continuum reverberation mapping of active galactic nuclei (AGNs) can provide new insight into the nature and geometry of the accretion flow. Some of the X-rays from the central corona irradiating the disc are absorbed, increasing the local disc tempe... Read More about Modelling continuum reverberation in active galactic nuclei: a spectral-timing analysis of the ultraviolet variability through X-ray reverberation in Fairall 9.