TP-AGB stars and stellar population properties of a post-starburst galaxy at $z \sim 2$ through optical and NIR spectroscopy with JWST
Fuente:
arXiv
Gespeichert in:
| Hauptverfasser: | , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2025
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866912470394732544 |
|---|---|
| author | Bevacqua, Davide Saracco, Paolo La Barbera, Francesco De Marchi, Guido De Propris, Roberto Ditrani, Fabio Gallazzi, Anna R. Giardino, Giovanna Marchesini, Danilo Pasquali, Anna Rawle, Tim D. Spiniello, Chiara Vazdekis, Alexandre Zibetti, Stefano |
| author_facet | Bevacqua, Davide Saracco, Paolo La Barbera, Francesco De Marchi, Guido De Propris, Roberto Ditrani, Fabio Gallazzi, Anna R. Giardino, Giovanna Marchesini, Danilo Pasquali, Anna Rawle, Tim D. Spiniello, Chiara Vazdekis, Alexandre Zibetti, Stefano |
| contents | We present a detailed optical and NIR spectral analysis of J-138717, a post-starburst galaxy at $z = 1.8845$ observed with JWST/NIRSpec, for which we derive a stellar mass of $3.5 \pm 0.2 \times 10^{10}$ M$_\odot$ and a stellar velocity dispersion of $198 \pm 10$ km s$^{-1}$. We estimate an age of $\sim0.9$ Gyr and a sub-solar metallicity (between $-0.4$ and $-0.2$ dex). We find generally consistent results when fitting the optical and NIR wavelength ranges separately or using different model libraries. The reconstruction of the star formation history indicates that the galaxy assembled most of its mass quickly and then rapidly quenched, $\sim0.4$ Gyr prior to observation. Line diagnostics suggest that the weak emission is probably powered by residual star formation (SFR$\sim0.2$M$_\odot$ yr$^{-1}$) or a low-luminosity AGN, with no strong evidence for outflows in ionized or neutral gas. We perform a detailed study of the NIR spectral indices by comparing observations with predictions of several state-of-the-art stellar population models. This is unprecedented at such a high redshift. In particular, the analysis of several CO and CN features argues against a heavy contribution of Thermally Pulsating (TP-)AGB stars. Observations align better with models that include a minimal contribution from TP-AGB stars, but they are also consistent with a mild contribution from TP-AGB stars, assuming a younger age (consistent with the fits). The analysis of other NIR spectral indices shows that current models struggle to reproduce observations. This highlights the need for improved stellar population models in the NIR, especially at young ages and low metallicities, which is most relevant for studying high redshift galaxies in the JWST era. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_07291 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | TP-AGB stars and stellar population properties of a post-starburst galaxy at $z \sim 2$ through optical and NIR spectroscopy with JWST Bevacqua, Davide Saracco, Paolo La Barbera, Francesco De Marchi, Guido De Propris, Roberto Ditrani, Fabio Gallazzi, Anna R. Giardino, Giovanna Marchesini, Danilo Pasquali, Anna Rawle, Tim D. Spiniello, Chiara Vazdekis, Alexandre Zibetti, Stefano Astrophysics of Galaxies We present a detailed optical and NIR spectral analysis of J-138717, a post-starburst galaxy at $z = 1.8845$ observed with JWST/NIRSpec, for which we derive a stellar mass of $3.5 \pm 0.2 \times 10^{10}$ M$_\odot$ and a stellar velocity dispersion of $198 \pm 10$ km s$^{-1}$. We estimate an age of $\sim0.9$ Gyr and a sub-solar metallicity (between $-0.4$ and $-0.2$ dex). We find generally consistent results when fitting the optical and NIR wavelength ranges separately or using different model libraries. The reconstruction of the star formation history indicates that the galaxy assembled most of its mass quickly and then rapidly quenched, $\sim0.4$ Gyr prior to observation. Line diagnostics suggest that the weak emission is probably powered by residual star formation (SFR$\sim0.2$M$_\odot$ yr$^{-1}$) or a low-luminosity AGN, with no strong evidence for outflows in ionized or neutral gas. We perform a detailed study of the NIR spectral indices by comparing observations with predictions of several state-of-the-art stellar population models. This is unprecedented at such a high redshift. In particular, the analysis of several CO and CN features argues against a heavy contribution of Thermally Pulsating (TP-)AGB stars. Observations align better with models that include a minimal contribution from TP-AGB stars, but they are also consistent with a mild contribution from TP-AGB stars, assuming a younger age (consistent with the fits). The analysis of other NIR spectral indices shows that current models struggle to reproduce observations. This highlights the need for improved stellar population models in the NIR, especially at young ages and low metallicities, which is most relevant for studying high redshift galaxies in the JWST era. |
| title | TP-AGB stars and stellar population properties of a post-starburst galaxy at $z \sim 2$ through optical and NIR spectroscopy with JWST |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2501.07291 |