Unveiling the Role of Multi-Phase AGN Outflows with MIRACLE

Speaker

Dr. Matteo Ceci (Università di Firenze)

Abstract

Galaxy evolution is tightly connected to Active Galactic Nuclei (AGN) through feedback processes in which gas accretion onto the supermassive black hole drives powerful multiphase outflows. Detailed studies in the local Universe are crucial to resolve the physical scales and gas phases involved, enabling a comprehensive view of AGN-host interactions. I will present first results from the MIRACLE (Mid-IR Activity of Circumnuclear Line Emission) program, combining JWST/MIRI, MUSE, and ALMA observations of seven nearby Seyfert galaxies. Thanks to JWST’s spatial resolution (50-150 pc), we probe atomic and molecular gas in the circumnuclear regions and assess the impact of AGN activity on their host galaxies. Focusing on NGC 1365, we trace the ionized outflow up to kiloparsec scales and constrain its energetics and effects on star formation (SF). By combining mid-IR diagnostics with advanced photoionization and kinematic models, we reproduce ~60 optical and mid-IR emission lines, disentangling AGN- and SF-driven components and providing robust estimates of gas density, ionization, extinction, and outflow mass. We show that classical methods commonly adopted in the literature can underestimate outflow masses by up to an order of magnitude.

Disk Reflection as the Origin of the X-ray Polarization of NGC 4151 with IXPE

Speaker

Dr. Elias Kammoun (California Institute of Technology) 

Abstract

The geometry of the X-ray emitting region around accreting supermassive black holes remains poorly constrained, but X-ray polarimetry now offers a new and direct perspective on it. I will present a spectro-polarimetric study of the nearby type-1 AGN NGC 4151, combining two long IXPE observations from 2022 and 2024 with simultaneous XMM-Newton and NuSTAR spectroscopy. IXPE reveals a polarization degree of 6–7% above 4 keV aligned with the radio jet, plus a distinct low-energy component at a different angle, providing evidence for at least two polarized components in the 2–8 keV band. While earlier work read the hard X-ray signal as a radially extended, slab-like corona, I will test an alternative: that the polarization is instead dominated by relativistic reflection from an accretion disk illuminated by a compact, lamp-post corona. Fitting the IXPE Stokes spectra with recently developed models, we find the data favor a low coronal height and a wide torus opening angle, with disk reflection supplying ~20% of the 2–8 keV flux. The same configuration reproduces the full 0.4–79 keV spectrum, showing that disk reprocessing by a compact corona can account for both the polarization and the broadband spectral properties of NGC 4151.

Seminar Connection

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