Print Email Facebook Twitter Nuclear high-ionisation outflow in the Compton-thick AGN NGC 6552 as seen by the JWST mid-infrared instrument Title Nuclear high-ionisation outflow in the Compton-thick AGN NGC 6552 as seen by the JWST mid-infrared instrument Author Álvarez-Márquez, J. (Centro de Astrobiología (INTA-CSIC)) Labiano, A. (Centro de Astrobiología (INTA-CSIC); ESAC) Guillard, P. (Sorbonne Université; Institut Universitaire de France) Dicken, D. (Royal Observatory) Argyriou, I. (Katholieke Universiteit Leuven) Patapis, P. (ETH Zürich) Kavanagh, P. J. (Dublin Institute for Advanced Studies) Alberts, S. (University of Arizona) Brandl, B.R. (TU Delft Astrodynamics & Space Missions; Universiteit Leiden) Date 2023 Abstract Context. During the commissioning of the James Webb Space Telescope (JWST), the mid-infrared instrument (MIRI) observed NGC 6552 with the MIRI Imager and the Medium-Resolution Spectrograph (MRS). NGC 6552 is an active galactic nucleus (AGN) at a redshift of 0.0266 (DL = 120 Mpc) classified as a Seyfert 2 nucleus in the optical and Compton-thick AGN in the X-ray. Aims. This work exemplifies and demonstrates the MRS capabilities to study the mid-infrared (mid-IR) spectra and characterise the physical conditions and kinematics of the ionised and molecular gas in the nuclear regions of nearby galaxies. Methods. MIRI Imager observations covers the full NGC 6552 galaxy at 5.6 μm. MRS observations covers its nuclear region (3.6 × 4.3 kpc at 17.7-27.9 μm) in a wavelength range between 4.9 and 27.9 μm. These observations were obtained with the aim to investigate the persistence of the MIRI detectors (residual signal left from previous bright source observations). However, NGC 6552 observations demonstrate the performance and power of the MIRI instrument even with a non-optimal observational strategy. Results. We obtained the nuclear, circumnuclear, and central mid-IR spectra of NGC 6552. They provide the first clear observational evidence for a nuclear outflow in NGC 6552. The outflow contributes to 67±7% of the total line flux independent of the ionisation potential (27-187 eV) and critical densities (104-4 × 106 cm-3), showing an average blue-shifted peak velocity of -127±45 km s-1 and an outflow maximal velocity of 698±80 km s-1. Since the mid-IR photons penetrate dusty regions as efficiently as X-ray keV photons, we interpret these results as the evidence for a highly ionised, non-stratified, AGN-powered, and fast outflowing gas in a low density environment (few 103 cm-3) located very close (< 0.2 kpc) to the Compton-thick AGN. Nine pure rotational molecular Hydrogen lines are detected and spectrally resolved, and exhibit symmetric Gaussian profiles, consistent with the galactic rotation, and with no evidence of outflowing H2 material. We detect a warm H2 mass of 1.9 ± 1.1 × 107 M⊙ in the central region (1.8 kpc in diameter) of the galaxy, with almost 30% of that mass in the circumnuclear region. Line ratios confirm that NGC 6552 has a Seyfert nucleus with a black hole mass estimated in the range of 0.6-6 million solar masses. Conclusions. This work demonstrates the power of the newly commissioned MIRI Medium Resolution Spectrograph to reveal new insights in the kinematics and ionisation state of the interstellar medium around the dusty nuclear regions of nearby active galaxies. Subject Galaxies: activeGalaxies: ISMGalaxies: kinematics and dynamicsGalaxies: SeyfertInstrumentation: high angular resolutionInstrumentation: spectrographs To reference this document use: http://resolver.tudelft.nl/uuid:5f5bb4bc-aa75-48aa-afa9-ea8c49d99dc8 DOI https://doi.org/10.1051/0004-6361/202244880 ISSN 0004-6361 Source Astronomy & Astrophysics, 672 Part of collection Institutional Repository Document type journal article Rights © 2023 J. Álvarez-Márquez, A. Labiano, P. Guillard, D. Dicken, I. Argyriou, P. Patapis, P. J. Kavanagh, S. Alberts, B.R. Brandl, More Authors Files PDF aa44880_22.pdf 6.1 MB Close viewer /islandora/object/uuid:5f5bb4bc-aa75-48aa-afa9-ea8c49d99dc8/datastream/OBJ/view