Illuminating the Active Universe: Multi-Wavelength and Multi-Messenger Insights into AGN

Session

X-Ray AGN

15 Sept 2026, 09:00

Auditorium Eridanus (ESO)

69. Illuminating the X-ray properties of AGN across cosmic time

Peter Boorman

15/09/2026, 09:00

Invited

Most active galactic nuclei (AGN) are viewed through substantial columns of gas and dust whose geometry, composition, and evolution are coupled to the central accretion flow. In this talk, I will briefly review the current state of X-ray AGN surveys and their role in constraining the evolution of AGN power and obscuration across cosmic time. A fundamental ingredient is the combination of...

68. The AGN content in eROSITA/DR2

Mara Salvato

15/09/2026, 09:30

Invited

Galaxy evolution can only be understood if its AGN phases are accounted for. For that, a complete and pure census of AGN is needed. Hunting for AGN in X-rays is the most obvious way to go, given the low emission from galaxies at this frequency. In the last 20 years, XMM and Chandra have mostly provided us with pencil-beam surveys, thus sampling the faint, high-redshift regime. Finally, with...

23. X-ray Polarization in Active Galactic Nuclei

Stefano Bianchi (Università degli Studi Roma Tre)

15/09/2026, 10:00

Invited

X-ray polarimetry has opened a new window on the physics of active galactic nuclei, providing direct information on geometry, magnetic fields, scattering regions, and the particle acceleration and emission processes operating in relativistic jets that cannot be obtained from spectroscopy, timing, or imaging alone. In this talk, I will review the emerging observational picture from recent X-ray...

33. The Limitations of AGN Reverberation Mapping: Bayesian analysis shows as few as 5% of MgII Sources may Reverberate

Hugh McDougall (The University of Queensland)

15/09/2026, 10:30

Regular

Reverberation mapping (RM) of Active galactic nuclei is a multi-messenger time domain that provides one of the most direct probes of the geometry and kinematics of the AGN broad-line region. It combines broad-band photometry and emission line spectroscopy to construct light curves to measure time delays between the continuum and line variability, with this lag time acting as a ruler of the...

8. Hard X-ray and Millimeter Broadband Study of AGN Corona

Xiurui Zhao (Caltech)

15/09/2026, 11:20

Regular

The X-ray emission in active galactic nuclei (AGN) is produced in a hot corona, where energetic electrons up-scatter UV/optical photons from the accretion disk into X-rays through inverse Compton scattering. Hard X-ray observations from NuSTAR provide key constraints on the coronal temperature and optical depth, while recent studies have revealed that millimeter (mm) synchrotron emission...

34. X-ray spectral steepness in AGN: accretion rate is not the whole story

Andrea Sacchi

15/09/2026, 11:40

Regular

Steep X-ray spectra in active galactic nuclei (AGN) are widely interpreted as a signature of high accretion rates, a claim gaining renewed relevance in light of the JWST discoveries of X-ray-weak AGN at high redshift. Are these primeval objects accreting near or beyond the Eddington limit? To address this, we analyzed the X-ray emission of a large AGN sample from the latest Sloan Digital Sky...

57. AGN in the X-ray band: recent results and implications for the big picture

Roberto Gilli (INAF-OAS Bologna)

Invited

Recent X-ray spectroscopic and polarimetric observations of nearby Seyfert galaxies are providing new constraints on the physics and geometry of the innermost AGN regions, where hot and dense plasmas are present and powerful outflows are launched. At the same time, in the distant Universe, new AGN populations discovered by JWST are escaping detection in the X-rays, even in the deepest X-ray...