JWST meets Chandra: a large population of Compton thick, feedback-free, and intrinsically X-ray weak AGN, with a sprinkle of SNe
Year: 2025
Type: article
Abstract: ABSTRACT We investigate the X-ray properties of a sample of 71 broad- and narrow-line active galactic nucleus (AGN) at 2$\lt$z$\lt$11 discovered by JWST in the GOODS (Great Observatory Origins Deep Survey) fields, which have the deepest Chandra observations ever obtained. Despite the widespread presence of AGN signatures in their rest-optical and -ultraviolet spectra, the vast majority of them is X-ray undetected. The stacked X-ray data of the non-detected sources also results in a non-detection. The upper limit on the X-ray emission for many of these AGN is one or even two orders of magnitude lower than expected from a standard AGN Spectral Energy Distribution (SED). X-ray absorption by clouds with large (Compton-thick) column density and low dust content, such as the broad-line region (BLR) clouds, can explain the X-ray weakness. In this scenario, the BLR covering factor should be much larger than in low-z AGN or luminous quasars; this is supported by the larger equivalent width of the broad component of H$\alpha$ in JWST-selected AGN. We also find that the JWST-discovered AGN lack prominent, fast outflows, suggesting that, in JWST-selected AGN, dense gas lingers in the nuclear region, resulting in large covering factors. We also note that a large fraction of JWST-selected AGN matches the definition of narrow-line Seyfert 1, typically accreting at high rates and characterized by a steep X-ray spectrum – this can further contribute to their observed weakness at high-z. Finally, we discuss that the broad Balmer lines used to identify type 1 AGN cannot be ascribed to very massive stars or supernovae, although we show that some of the faintest broad lines could potentially be associated with superluminous SNe.
Source: Apollo (University of Cambridge)
Authors: Maiolino, Roberto, Risaliti, Guido, Signorini, Matilde, Trefoloni, Bartolomeo, Juodžbalis, Ignas, Scholtz, Jan, Übler, Hannah, D’Eugenio, Francesco, Carniani, Stefano, Fabian, Andy, Ji, Xihan, Mazzolari, Giovanni, Bertola, Elena, Brusa, Marcella, Bunker, Andrew J, Charlot, Stephane, Comastri, Andrea, Cresci, Giovanni, DeCoursey, Christa Noel, Egami, Eiichi, Fiore, Fabrizio, Gilli, Roberto, Perna, Michele, Tacchella, Sandro, Venturi, Giacomo
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7010792034
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