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Breaking Modeling Degeneracies in the Phoenix Cluster QSO with Hard X-ray Data

Presentation #202.03 in the session AGN I.

Published onMay 03, 2024
Breaking Modeling Degeneracies in the Phoenix Cluster QSO with Hard X-ray Data

Galaxy clusters are the largest virialized objects in the universe, yet they are far from their final form. In the clusters, hundreds of galaxies are embedded in the hot and tenuous intracluster medium (ICM) that shines brightly in X-rays mainly via thermal bremsstrahlung. Galaxy clusters continuously evolve not only through the interaction with other clusters, i.e.: mergers, but also through the interaction of their constituents. Due to the enormous gravitational potential provided by the dark matter halo, a central galaxy sinks at the bottom of this potential well and forms a central supermassive black hole (SMBH). Due to the large amounts of accreting material available to feed the SMBH, the object begins to interact with the ICM through relativistic jets and outflows that mix and heat the plasma. This feeding and feedback mechanism of the Active Galactic Nuclei (AGN) is thought to be what still maintains the central regions of galaxy clusters bright beyond their life span; while the observed X-ray emission suggest the cooling time of clusters is much shorter than the Hubble time, cool cores are ubiquitous. The importance of the AGN in the evolution and shaping of galaxy clusters is well known, yet the mechanisms in action are not well understood. The Phoenix cluster at z=0.6 is the most X-ray luminous cluster whose central AGN is one of the most powerful in the known universe. In this work, we jointly analyze deep (>500ks) Chandra and moderate (>30ks) NuSTAR data using spectro-imaging methods. With only the deep Chandra data, vastly different physical models are able to fit the data equally well — determining which model truly describes the quasar (QSO) is only possible using the hard X-ray (>7 keV) information that is provided by NuSTAR. Here, we will present the results of an analysis to model the full hard X-ray-through-radio spectral energy distribution of the powerful central QSO in Phoenix, along with an estimate of its bolometric luminosity.

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