Extended high-ionization [MgIV] emission tracing widespread shocks in starbursts seen by JWST /NIRSpec
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arXiv
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| Natura: | Preprint |
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2024
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| author | Pereira-Santaella, Miguel García-Bernete, Ismael González-Alfonso, Eduardo Alonso-Herrero, Almudena Colina, Luis García-Burillo, Santiago Rigopoulou, Dimitra Arribas, Santiago Perna, Michele |
| author_facet | Pereira-Santaella, Miguel García-Bernete, Ismael González-Alfonso, Eduardo Alonso-Herrero, Almudena Colina, Luis García-Burillo, Santiago Rigopoulou, Dimitra Arribas, Santiago Perna, Michele |
| contents | We report the detection of extended (>0.5-1kpc) high-ionization [MgIV] 4.487 $μ$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 [MgIV] luminosity is well correlated with that of H recombination lines, which mainly trace star forming clumps in these objects, and that the [ArVI] 4.530 $μ$m (75 eV), usually seen in AGN, is undetected. On 100-400pc scales, the [MgIV] line profiles are broader (sigma([MgIV])=90 +- 25 km/s) and shifted (Delta_v up to +- 50 km/s) compared to those of the H recombination lines and lower ionization transitions (e.g., sigma(Hu-12)=57 +- 15 km/s). The [MgIV] kinematics follow the large scale rotating velocity field of these galaxies and the broad [MgIV] 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 as a result of ionizing shocks associated with star-formation, is the most likely origin of the [MgIV] emission. We also computed new grids of photoionization and shock models to investigate where the [MgIV] line originates. Shocks with velocities of 100-130 km/s reproduce the observed line ratios and the [MgIV] 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 [MgIV] line. Future studies on the stellar feedback from SNe will benefit from the [MgIV] line that is little affected by obscuration and, in absence of an AGN, can only be produced by shocks due to its high ionization potential. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_16641 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Extended high-ionization [MgIV] emission tracing widespread shocks in starbursts seen by JWST /NIRSpec Pereira-Santaella, Miguel García-Bernete, Ismael González-Alfonso, Eduardo Alonso-Herrero, Almudena Colina, Luis García-Burillo, Santiago Rigopoulou, Dimitra Arribas, Santiago Perna, Michele Astrophysics of Galaxies We report the detection of extended (>0.5-1kpc) high-ionization [MgIV] 4.487 $μ$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 [MgIV] luminosity is well correlated with that of H recombination lines, which mainly trace star forming clumps in these objects, and that the [ArVI] 4.530 $μ$m (75 eV), usually seen in AGN, is undetected. On 100-400pc scales, the [MgIV] line profiles are broader (sigma([MgIV])=90 +- 25 km/s) and shifted (Delta_v up to +- 50 km/s) compared to those of the H recombination lines and lower ionization transitions (e.g., sigma(Hu-12)=57 +- 15 km/s). The [MgIV] kinematics follow the large scale rotating velocity field of these galaxies and the broad [MgIV] 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 as a result of ionizing shocks associated with star-formation, is the most likely origin of the [MgIV] emission. We also computed new grids of photoionization and shock models to investigate where the [MgIV] line originates. Shocks with velocities of 100-130 km/s reproduce the observed line ratios and the [MgIV] 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 [MgIV] line. Future studies on the stellar feedback from SNe will benefit from the [MgIV] line that is little affected by obscuration and, in absence of an AGN, can only be produced by shocks due to its high ionization potential. |
| title | Extended high-ionization [MgIV] emission tracing widespread shocks in starbursts seen by JWST /NIRSpec |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2404.16641 |