Thanks Sarah!!! MIRI MRS is awesome!!!

Thanks!! indeed, this is just a teaser :)

This research was done at @IAC_Astrofisica and @KICC_official , in collaboration with colleagues at other institutions around the globe. Stay tunned for more ✨QSOFEED✨ JWST/MIRI results!! arxiv.org/abs/2504.01595

This fantastic JWST/MIRI data from Cycle 2 GO proposal 3655 allowed us to start exploring the role of various AGN and galaxy properties including ionizing continuum, obscuration, electron density, and jet-ISM interactions on some of the spectral differences listed above. I hope you like it!

The electron densities that we measure from the [NeV]14.3/24.3 ratio (log ne>2.8 cm-3) range from are similar to those derived from the optical trans-auroral lines, and higher than those from the [SII] doublet.

In the case of J1010 & J1100, these SFRs are much lower than the SFRs measured from optical spectra probing the central 5-6 kpc of the QSO2s. This is likely due to the destruction of some PAH molecules by AGN radiation in the central kpc of the galaxies.

They show PAH emission features with EWs ranging from <0.002 to 0.075 micron, from which we measure a larger contribution from neutral molecules (PAH 11.3/6.2=1.3-3.4) and SFRs of <3-7 Msun/yr.

We measure warm molecular gas masses of 1-4x10^7 Msun and warm-to-cold gas mass ratios of 1-2%, with molecular gas excitation likely due to jet-induced shocks in J1430, and to UV heating and/or turbulence in J1509.

The [NeV]/[NeII] ratios range from 0.1 to 2.1 and [NeIII]/[NeII] from 1.0 to 3.5, indicating different coronal line and ionizing continuum strengths. Look at the low values of these ratios of J1010 (pink circle). The other four QSO2s have values similar to Seyfert galaxies.

In addition, two of the QSO2s show absorption bands of CO, H2O, and aliphatic grains. Together with the different silicate feature strengths, this indicates different levels of nuclear obscuration across the sample.

For comparison, Zakamska et al. (2016) reported a mean value of S9.7=-0.41±0.48 (median of -0.30) for a sample of 46 type-2 AGN (QSOs & Seyferts) observed with Spitzer/IRS.

One of the main differences are the silicate features. They show 9.7 micron silicate features going from emission (strength of S9.7=0.5 in J1010) to relatively strong absorption (S9.7=-1.0 in J1356) and 18 and 23 micron silicates either in emission or flat.

On the other hand, their nuclear mid-infrared spectra, which correspond to the central kiloparsec of the QSO2s, exhibit an unexpected diversity of both continua and features!!! Look at these beautiful JWST/MIRI spectra again 🤩🤩🤩

global SFRs that place them above the main sequence, and practically identical optical spectral shape (see optical SDSS spectra in this plot) and [OIII] luminosity.

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. The five QSO2s that we studied were selected in the optical and they have log Lbol=45.5-46.0 erg/s,