Halfway to the Peak: Ice Absorption Bands at <i>z</i> ≈ 0.5 with JWST MIRI/MRS
Abstract This paper presents the first combined detections of CO 2 , CO, XCN, and water ices beyond the local Universe. We find gas-phase CO in addition to the solid phase CO. Our source, SSTXFLS J172458.3+591545, is a z = 0.494 star-forming galaxy that also hosts a deeply obscured AGN. The profiles of its ice features are consistent with those of other Galactic and local galaxy sources, and the implied ice mantle composition is similar to that of even more obscured sources. The ice features indicate the presence of a compact nucleus in our Galaxy and allow us to place constraints on its density and temperature ( n > 10 5 cm −3 and T = 20–90 K). We infer the visual extinction towards this nucleus to be A V ≈ 6–7. An observed plot of τ Si versus τ CO2 / τ Si can be viewed as a probe for both the total dustiness of a system as well as the clumpiness of the dust along the line of sight. This paper highlights the potential of using JWST MIRI spectra to study the dust composition and geometric distribution of sources beyond the local Universe.
Authors
- Jed McKinney (ORCID: https://orcid.org/0000-0002-6149-8178)
- Thomas S. -Y. Lai (ORCID: https://orcid.org/0000-0001-8490-6632)
- Jason Young (ORCID: https://orcid.org/0000-0002-5830-9233)
- Miriam Eleazer (ORCID: https://orcid.org/0000-0002-4690-4502)
- H. W. W. Spoon (ORCID: https://orcid.org/0000-0002-8712-369X)
- Sylvain Veilleux (ORCID: https://orcid.org/0000-0002-3158-6820)
- L. Armus (ORCID: https://orcid.org/0000-0003-3498-2973)
- D. Farrah (ORCID: https://orcid.org/0000-0003-1748-2010)
- Lin Yan (ORCID: https://orcid.org/0000-0003-1710-9339)
- Mark Lacy (ORCID: https://orcid.org/0000-0002-3032-1783)
- Alexandra Pope (ORCID: https://orcid.org/0000-0001-8592-2706)
- Anna Sajina (ORCID: https://orcid.org/0000-0002-1917-1200)
Institutions
- University of Hawaiʻi at Mānoa (US)
- Tufts University (US)
- California Institute of Technology (US)
- Amherst College (US)
- Cornell University (US)
- Williams College (US)
- University of Massachusetts Amherst (US)
- Joint Space Science Institute (US)
- University of Maryland, College Park (US)
- The University of Texas at Austin (US)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-05-23
- DOI
- https://doi.org/10.3847/1538-4357/adc44a
- Citations
- 1
- Primary Topic
- Astrophysics and Star Formation Studies
- Type
- article
- Field-Weighted Citation Impact
- 1.15
Funders
- Space Telescope Science Institute