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| Main Authors: | , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2512.02997 |
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| author | Gómez, A. Crespo Colina, L. Pérez-González, P. G. Álvarez-Márquez, J. García-Marín, M. Alonso-Herrero, A. Annunziatella, M. Bik, A. Bosman, S. Bunker, A. J. Labiano, A. Langeroodi, D. Rinaldi, P. Östlin, G. Boogaard, L. Gillman, S. Barro, G. Finkelstein, S. L. Leung, G. C. K. |
| author_facet | Gómez, A. Crespo Colina, L. Pérez-González, P. G. Álvarez-Márquez, J. García-Marín, M. Alonso-Herrero, A. Annunziatella, M. Bik, A. Bosman, S. Bunker, A. J. Labiano, A. Langeroodi, D. Rinaldi, P. Östlin, G. Boogaard, L. Gillman, S. Barro, G. Finkelstein, S. L. Leung, G. C. K. |
| contents | We present new MIRI F560W, F770W and F1000W imaging of GN-z11, extending the previous rest-frame coverage from 0.38 to 0.86$μ$m. We report significant detections (14$σ$) in the F560W and F770W images, and a marginal detection (3.2$σ$) in F1000W. Here, we analyse its SED combining new MIRI imaging data with archival NIRSpec/Prism and MRS spectroscopy, and NIRCam imaging. The continuum emission shows a flat energy distribution, in f$_ν$, up to 0.5$μ$m, compatible with the presence of a mixed stellar population of young (4$\pm$1 Myr) and mature (63$\pm$23 Myr) stars that also account for the [O III], H$β$ and H$α$ emission lines. The continuum at rest-frame 0.66$μ$m shows a 36$\pm$3% flux excess above the predicted flux for a mixed stellar population, pointing to the presence of an additional source contributing at these wavelengths. This excess increases to 91$\pm$28% at rest-frame 0.86$μ$m, although with a large uncertainty due to the marginal detection in the F1000W filter. We consider that hot dust emission in the dusty torus around a type 2 AGN could be responsible for the observed excess. Alternatively, this excess could be due to hot dust emission or to a photoluminiscence dust process (Extended Red Emission, ERE) under the extreme UV radiation field, as observed in some local metal-poor galaxies and in young compact starbursts. The presence of a type 1 AGN is not supported by the observed SED since high-z QSOs contribute at wavelengths above rest-frame 1$μ$m, and an additional ad-hoc red source would be required to explain the observed flux excess at 0.66 and 0.86$μ$m. Additional deep MIRI imaging covering the rest-frame near-IR are needed to confirm the flux detection at 10$μ$m with higher significance, and to discriminate between the different hot dust emission in the extreme starburst and AGN scenarios with MIRI imaging at longer wavelengths. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_02997 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | MIRI spectrophotometry of GN-z11: Detection and nature of an optical red continuum component Gómez, A. Crespo Colina, L. Pérez-González, P. G. Álvarez-Márquez, J. García-Marín, M. Alonso-Herrero, A. Annunziatella, M. Bik, A. Bosman, S. Bunker, A. J. Labiano, A. Langeroodi, D. Rinaldi, P. Östlin, G. Boogaard, L. Gillman, S. Barro, G. Finkelstein, S. L. Leung, G. C. K. Astrophysics of Galaxies We present new MIRI F560W, F770W and F1000W imaging of GN-z11, extending the previous rest-frame coverage from 0.38 to 0.86$μ$m. We report significant detections (14$σ$) in the F560W and F770W images, and a marginal detection (3.2$σ$) in F1000W. Here, we analyse its SED combining new MIRI imaging data with archival NIRSpec/Prism and MRS spectroscopy, and NIRCam imaging. The continuum emission shows a flat energy distribution, in f$_ν$, up to 0.5$μ$m, compatible with the presence of a mixed stellar population of young (4$\pm$1 Myr) and mature (63$\pm$23 Myr) stars that also account for the [O III], H$β$ and H$α$ emission lines. The continuum at rest-frame 0.66$μ$m shows a 36$\pm$3% flux excess above the predicted flux for a mixed stellar population, pointing to the presence of an additional source contributing at these wavelengths. This excess increases to 91$\pm$28% at rest-frame 0.86$μ$m, although with a large uncertainty due to the marginal detection in the F1000W filter. We consider that hot dust emission in the dusty torus around a type 2 AGN could be responsible for the observed excess. Alternatively, this excess could be due to hot dust emission or to a photoluminiscence dust process (Extended Red Emission, ERE) under the extreme UV radiation field, as observed in some local metal-poor galaxies and in young compact starbursts. The presence of a type 1 AGN is not supported by the observed SED since high-z QSOs contribute at wavelengths above rest-frame 1$μ$m, and an additional ad-hoc red source would be required to explain the observed flux excess at 0.66 and 0.86$μ$m. Additional deep MIRI imaging covering the rest-frame near-IR are needed to confirm the flux detection at 10$μ$m with higher significance, and to discriminate between the different hot dust emission in the extreme starburst and AGN scenarios with MIRI imaging at longer wavelengths. |
| title | MIRI spectrophotometry of GN-z11: Detection and nature of an optical red continuum component |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2512.02997 |