Prof. Dimitra Rigopoulou

Abstract:

Type-2 quasars (QSO2s) are active galactic nuclei (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 . 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 (̊m C_T=0.45±^ 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 fit 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 BayesClumpy 0.26 _ 0.18 and ̊m C_T=0.66±^ 0.16 _ 0.17 for the CLUMPY and CAT3D-WIND models) and low inclinations (̊m i=50^̧irc±^ 8^̧irc _ 9^̧irc and ̊m i=13^̧irc±^ 7^̧irc _ 6^̧irc ). 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 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. silicate features in absorption. This ̧olor black supports

Abstract:

The polar mid-infrared (MIR) emission detected within tens to hundreds of parsecs in some active galactic nuclei (AGN) has been associated with dusty winds driven away by radiation pressure. The physical characterization of this extended polar emission remains uncertain. Here, we combine 10–21 μm JWST/Mid-InfRared Instrument (MIRI) imaging observations with 7–25 μm JWST/MIRI MRS integral field spectroscopic observations of six nearby, D¯=35.4±4.6 Mpc, AGN from the GATOS Survey to quantify the nature of the extended MIR emission at ∼75 pc resolution at 21 μm. These AGN have similar bolometric luminosities, log10(L¯bol[ergs−1])=44.0±0.3 , span a wide range of optical outflow rates, Ṁ= 0.003–0.21 M⊙ yr−1, column densities, log10(NHX−ray[cm−2])= 22.2–24.3, and Eddington ratios, λEdd = 0.005–0.06. We cross-correlate the line-only and continuum-only images and find a poor correlation, which indicates that the extended MIR continuum emission is spatially uncorrelated with the warm outflows associated with narrow emission lines within 10–15 μm. Line emission is resolved along the jet axis, while dust emission is perpendicular to it. The 75–450 pc continuum emission has a fairly constant dust temperature, Td=132−7+7 K, and mass, Md=728−27+29 M⊙. Using the conditions of energy balance between radiation-pressure and gravity (λEdd versus NH), we find that our AGN sample is in the gravitationally bounded regime consistent with no detection of dusty winds. At 10 μm, the level of extended line emission contribution is correlated with the outflow kinetic energy and mass outflow rates. We find no correlation with the AGN properties. These results indicate that the radio jet may be triggering the gas outflow and line emission, while the extended dust emission is distributed in molecular clouds and/or shocked regions.

Abstract:

Active galactic nuclei (AGNs), star formation (SF), and galaxy interactions can drive turbulence in the gas of the interstellar medium (ISM), which, in turn, plays a role in SF taking place within galaxies. The impact on molecular gas is of particular importance, as it serves as the primary fuel for SF. Our goal is to investigate the origin of turbulence and the emission of molecular gas, as well as low-and-intermediate-ionisation gas, in the inner few kpc of both AGN hosts and star-forming galaxies (SFGs). We used archival JWST MIRI/MRS observations of a sample consisting of 54 galaxies at z<0.1. We present flux measurements for the H_2 S(5)łambda6.9091μm ii łambda6.9853μm ii łambda5.3403μm, and iii łambda8.9914μm emission lines along with velocity dispersion estimated by the W_̊m 80 parameter. For galaxies with coronal line emission, we included measurements of the v łambda5.6098μm line. We compared the line ratios to photoionisation and shock models to explore the origin of the gas emission. AGNs exhibit broader emission lines than SFGs, with the largest velocity dispersions observed in radio-strong (RS) AGNs. The H_2 gas is less turbulent compared to ionised gas, while coronal gas presents higher velocity dispersions. The W_ 80 values for the ionised gas show a decrease when going from the nucleus out to radii of approximately 0.5--1 kpc, followed by an outward increase up to 2--3 kpc. In contrast, the H_2 line widths generally display increasing profiles with distance from the center. Correlations between the W_̊m 80 parameter and line ratios such as H_2:S(5)/ ii and ii ii indicate that the most turbulent gas is associated with shocks, enhancing H_2 and ii emissions. Based on the observed line ratios and velocity dispersions, the ii emission is consistent with predictions of fast shock models, while the H_2 emission is likely associated with molecules formed in the post-shock region. We speculate that these shocked gas regions are produced by AGN outflows and jet-cloud interactions in AGN-dominated sources; whereas in SFGs, they might be created through stellar winds and mergers. This shock-induced gas heating may be an important mechanism of AGN (or stellar) feedback, preventing the gas from cooling and forming new stars.