Detalles de publicación

PP 025156

Silicate emission in a type-2 quasar: JWST/MIRI constraints on torus geometry and radiative feedback

C. Ramos Almeida(1,2), A. Asensio Ramos(1,2), C. Westerdorp Plaza(1,2), I. García-Bernete(3), E. Lopez-Rodriguez(4), S. Hönig(5), A. Audibert(1,2), et al.
(1) IAC, (2) ULL, (3) CAB, (4) University of South Carolina, (5) University of Southampton
Abstract:Type-2 quasars (QSO2s) are AGN seen through a significant amount of dust and gas that obscures the central supermassive black hole and the broad line region. Despite this, recent mid-infrared spectra of the central 0.5-1.1 kpc of five QSO2s at z~0.1, obtained with the MRS module of JWST/MIRI, revealed 9.7, 18, and 23 micron silicate features in emission in two of them. This indicates that the high angular resolution of JWST/MIRI now allows us to peer into their nuclear region, exposing some of the directly illuminated dusty clouds that produce silicate emission. To test this, we fitted the nuclear mid-infrared spectrum of the QSO2 with the strongest silicate features, J1010, with two different sets of torus models implemented in an updated version of the Bayesian tool {\tt BayesClumpy}. These are the CLUMPY and the CAT3D-WIND models. The CAT3D-WIND model is preferred by the observations based on the marginal likelihood and fit residuals, although the two torus models successfully reproduce the spectrum by means of intermediate covering factors ($\rm C_T=0.45\pm^{0.26}_{0.18}$ and $\rm C_T=0.66\pm^{0.16}_{0.17}$ for the CLUMPY and CAT3D-WIND models) and low inclinations ($\rm i=50^\circ\pm^{8^\circ}_{9^\circ}$ and $\rm i=13^\circ\pm^{7^\circ}_{6^\circ}$). Indeed, four of the five QSO2s with JWST/MIRI observations, including J1010, are in the blowout or ''forbidden'' region of the Eddington ratio-column density diagram, indicating that they are actively clearing gas and dust from their nuclear regions, leading to reduced covering factors. This is in contrast with Seyfert 2 galaxies observed with JWST, which are in the ''permitted'' regions of the diagram and show 9.7 micron silicate features in absorption. This supports a scenario where the more luminous the AGN and the higher their Eddington ratio, the lower the torus covering factor, driven by radiation pressure on dusty gas.

 
Aceptado para publicación en A&A | Enviado el 2025-12-03 | Proyecto PID2022-141105NB-I00