Extended high-ionization [Mg IV] emission tracing widespread shocks in starbursts seen by JWST/NIRSpec
We report the detection of extended (> 0.5-1 kpc) high-ionization [Mg IV] 4.487 mu m (80 eV) emission in four local luminous infrared galaxies observed with JWST/NIRSpec. Excluding the nucleus and outflow of the Type 1 active galactic nucleus (AGN) in the sample, we find that the [Mg IV] luminosi...
| Autores: | , , , , , , , , |
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| Tipo de documento: | artigo |
| Data de publicação: | 2024 |
| País: | España |
| Recursos: | Universidad de Alcalá (UAH) |
| Repositório: | e_Buah Biblioteca Digital Universidad de Alcalá |
| Idioma: | inglês |
| OAI Identifier: | oai:ebuah.uah.es:10017/67611 |
| Acesso em linha: | http://hdl.handle.net/10017/67611 https://dx.doi.org/10.1051/0004-6361/202449982 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Galaxies: active Galaxies: evolution Galaxies: starburst Infrared: ISM Astronomía Astronomy |
| Resumo: | We report the detection of extended (> 0.5-1 kpc) high-ionization [Mg IV] 4.487 mu m (80 eV) emission in four local luminous infrared galaxies observed with JWST/NIRSpec. Excluding the nucleus and outflow of the Type 1 active galactic nucleus (AGN) in the sample, we find that the [Mg IV] luminosity is well correlated with that of H recombination lines, which mainly trace star-forming clumps in these objects, and that the [Ar VI] 4.530 mu m (75 eV), usually seen in AGN, is undetected. On 100-400 pc scales, the [Mg IV] line profiles are broader (sigma([Mg IV]) = 90 +/- 25 km s(-1)) and shifted (Delta v up to +/- 50 km s(-1)) compared to those of the H recombination lines and lower ionization transitions (e.g., sigma(Hu-12) = 57 +/- 15 km s(-1)). The [Mg IV] kinematics follow the large-scale rotating velocity field of these galaxies, and the broad [Mg IV] profiles are compatible with the broad wings detected in the H recombination lines. Based on these observational results, extended highly ionized gas more turbulent than the ambient interstellar medium, possibly a result of ionizing shocks associated with star formation, is the most likely origin of the [Mg IV] emission. We also computed new grids of photoionization and shock models to investigate where the [Mg IV] line originates. Shocks with velocities of 100-130 km s(-1) reproduce the observed line ratios and the [Mg IV] luminosity agrees with that expected from the mechanical energy released by supernove (SNe) in these regions. Therefore, these models support shocks induced by SNe as the origin of the [Mg IV] line. Future studies on the stellar feedback from SNe will benefit from the [Mg IV] line that is little affected by obscuration and, in the absence of an AGN, can only be produced by shocks due to its high ionization-potential. |
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