GATOS – IX. A detailed assessment and treatment of emission line contamination in <i>JWST</i> /MIRI images of nearby Seyfert galaxies
ABSTRACT Broad-band mid-infrared (MIR) imaging with high-spatial resolution is useful to study extended dust structures in the circumnuclear regions of nearby active galactic nuclei. However, broad-band imaging filters cannot distinguish dust continuum emission from emission lines, and so accounting for the emission line contamination becomes crucial in studying extended dust in these environments. This paper uses Cycle 1 MIR imaging from the James Webb Space Telescope's Mid-Infrared Instrument (JWST/MIRI) and spectroscopy from the Medium-Resolution Spectrometer (JWST/MRS) for 11 local Seyfert galaxies, as part of the Galactic Activity, Torus and Outflow Survey (GATOS). Three of the objects (NGC 3081, NGC 5728, and NGC 7172) exist in both data sets, allowing direct measurement of the line emission using the spectroscopy for these objects. We find that extended MIR emission persists on scales of 100 s of parsecs after the removal of contamination from emission lines. Further, the line contamination levels vary greatly between objects (from 5 per cent to 30 per cent in the F1000W filter), and across filters, so cannot be generalized across a sample and must be carefully treated for each object and band. We also test methods to estimate the line contamination when only MRS spectroscopy or MIRI imaging is available, using pre-JWST ancillary data. We find that these methods estimate the contamination within 10 percentage points. This paper serves as a useful guide for methods to quantify and mitigate for emission line contamination in MIRI broad-band imaging.
Authors
- H. Haidar (ORCID: https://orcid.org/0000-0002-3741-6136)
- D. J. Rosario (ORCID: https://orcid.org/0000-0002-0001-3587)
- C. Packham (ORCID: https://orcid.org/0000-0001-7827-5758)
- I. García-Bernete (ORCID: https://orcid.org/0000-0002-9627-5281)
- A. Alonso‐Herrero (ORCID: https://orcid.org/0000-0001-6794-2519)
- N. A. Levenson (ORCID: https://orcid.org/0000-0003-4209-639X)
- E. K. S. Hicks (ORCID: https://orcid.org/0000-0002-4457-5733)
- A. Audibert (ORCID: https://orcid.org/0000-0003-3589-3294)
- S. García‐Burillo (ORCID: https://orcid.org/0000-0003-0444-6897)
- Donají Esparza-Arredondo (ORCID: https://orcid.org/0000-0001-8042-9867)
- Lulu Zhang (ORCID: https://orcid.org/0000-0003-4937-9077)
- Steph Campbell (ORCID: https://orcid.org/0000-0001-9520-7765)
- D. Rigopoulou (ORCID: https://orcid.org/0000-0001-6854-7545)
- Enrique López-Rodríguez (ORCID: https://orcid.org/0000-0001-5357-6538)
- M. Pereira-Santaella (ORCID: https://orcid.org/0000-0002-4005-9619)
- E. Bellocchi (ORCID: https://orcid.org/0000-0001-9791-4228)
- O. González-Martín (ORCID: https://orcid.org/0000-0002-2356-8358)
- S. F. Hönig
- David G. Delaney
Institutions
- Universidad Complutense de Madrid (ES)
- Space Telescope Science Institute (US)
- University of Alaska Fairbanks (US)
- University of Alaska Anchorage (US)
- University of South Carolina (US)
- Universidad de La Laguna (ES)
- National Institutes of Natural Sciences (JP)
- European University Cyprus (CY)
- University of Oxford (GB)
- Instituto de Física Fundamental (ES)
- Université Bourgogne Franche-Comté (FR)
- Centro de Astrobiología (ES)
- Instituto de Astrofísica de Canarias (ES)
- Spanish National Observatory (ES)
- National Astronomical Observatory of Japan (JP)
- University of Southampton (GB)
- The University of Texas at San Antonio (US)
- Instituto Tecnológico de Morelia (MX)
- Newcastle University (GB)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society
- Published
- 2025-10-07
- DOI
- https://doi.org/10.1093/mnras/staf1719
- Citations
- 1
- Primary Topic
- Astronomy and Astrophysical Research
- Type
- article
- Field-Weighted Citation Impact
- 1.19
Funders
- National Aeronautics and Space Administration
- California Institute of Technology
- Space Telescope Science Institute
- UK Research and Innovation
- Ministerio de Ciencia, Innovación y Universidades
- European Commission
- Jet Propulsion Laboratory
- Science and Technology Facilities Council
- European Regional Development Fund
- Agencia Estatal de Investigación