GOALS-JWST: Mid-infrared Spectroscopy of the Nucleus of NGC 7469

Abstract

We present mid-infrared spectroscopic observations of the nucleus of the nearby Seyfert galaxy NGC 7469 taken with the MIRI instrument on the James Webb Space Telescope (JWST) as part of Directors Discretionary Time Early Release Science program 1328. The high-resolution nuclear spectrum contains 19 emission lines covering a wide range of ionization. The high-ionization lines show broad, blueshifted emission reaching velocities up to 1700 km s−1 and FWHM ranging from ∼500 to 1100 km s−1. The width of the broad emission and the broad-to-narrow line flux ratios correlate with ionization potential. The results suggest a decelerating, stratified, AGN-driven outflow emerging from the nucleus. The estimated mass outflow rate is 1–2 orders of magnitude larger than the current black hole accretion rate needed to power the AGN. Eight pure rotational H2 emission lines are detected with intrinsic widths ranging from FWHM ∼125 to 330 km s−1. We estimate a total mass of warm H2 gas of ∼1.2 × 107 M ⊙ in the central 100 pc. The PAH features are extremely weak in the nuclear spectrum, but a 6.2 μm PAH feature with an equivalent width of ∼0.07 μm and a flux of 2.7 × 10−17 W m−2 is detected. The spectrum is steeply rising in the mid-infrared, with a silicate strength of ∼0.02, significantly smaller than seen in most PG QSOs but comparable to other Seyfert 1s. These early MIRI mid-infrared IFU data highlight the power of JWST to probe the multiphase interstellar media surrounding actively accreting supermassive black holes.

GOALS-JWST: Pulling Back the Curtain on the AGN and Star Formation in VV 114

“…The emission line ratios show variation between apertures indicative of both widespread star formation and shock excitation. We do not detect any of the high-ionization coronal lines typically found in the mid-IR spectra of AGN-dominated galaxies (e.g., [Ne V]; Genzel et al 1998;Lutz et al 2000;Sturm et al 2002;Weedman et al 2005;Armus et al 2007) in contrast to JWST observations of NGC 7469 that show nine well-detected coronal lines excited by high-energy photons from the central AGN (Armus et al 2023). ) with FWHM values ranging between 150 and 200 km s −1 and show no trend with the emission line ionization potential.…”

The Interaction between AGN and Starburst Activity in the Circumnuclear Region of NGC 7469 as Viewed with JWST

“…NGC 7469 was included in the GOALS-JWST (ID 1328; co-PIs: L. Armus and A. Evans) Early Release Science program (Lai & Armus 2022;U et al 2022;Armus & Lai 2023). The MIRI/MRS observations were carried out using a set of four integral-field units (channels 1 to 4) that span 4.9-28.1 μm with three grating settings (short, medium, and long subbands).…”

“…In addition to the heating effect deduced from the analysis of the rotational H 2 spectrum (Section 3.3), AGN activity can also impact the host galaxy by expelling gas through a wind or outflow (García-Bernete et al 2022;U et al 2022;Armus et al 2023). To check whether the central starburst activity of NGC 7469 is influenced by mechanical processes, we examine the velocity field of the central region of the galaxy using the strongest of the well-isolated ionic emission lines (Figure 8).…”

A Framework for Modeling Polycyclic Aromatic Hydrocarbon Emission in Galaxy Evolution Simulations

“…With the launch of the JWST in 2021, observational studies of PAHs in galaxies are poised to enter a renaissance-already JWST is revealing the impact of galactic environment on PAH emission in galaxies near and far at unprecedented sensitivity and spatial resolution (e.g., Armus et al 2023;Chastenet et al 2022Chastenet et al , 2023Dale et al 2023;Egorov et al 2023;Evans 2022;Langeroodi & Hjorth 2023;Lai et al 2022;U et al 2022;Sandstrom et al 2023). What is missing thus far is a quantitative methodology for modeling the physical processes that drive the evolution of dust in the ISM in galaxies that span a wide range of physical conditions, and connecting these processes to the emergent PAH emission.…”