Transition from Outside-in to Inside-Out at $z\sim 2$: Evidence from Radial Profiles of Specific Star Formation Rate based on JWST/HST
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arXiv
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| Autori principali: | , , , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866911568183164928 |
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| author | Song, Jie Wang, Enci Jia, Cheng Lyu, Cheqiu Chen, Yangyao Wang, Jinyang Li, Fujia Ding, Weiyu Fang, Guanwen Kong, Xu |
| author_facet | Song, Jie Wang, Enci Jia, Cheng Lyu, Cheqiu Chen, Yangyao Wang, Jinyang Li, Fujia Ding, Weiyu Fang, Guanwen Kong, Xu |
| contents | By combining high-resolution observations from JWST and HST, we have measured the stellar masses, star formation rates (SFRs), and multi-wavelength morphologies of galaxies in the CANDELS fields. Furthermore, based on rest-frame 1 $μ$m morphologies, we have derived spatially resolved stellar mass and SFR surface density ($Σ_*$ and $Σ_{\rm SFR}$) profiles for 46,313 galaxies with reliable structural measurements at $0<z<4$ and $\log(M_\ast /M_{\odot})>8$, and provide the corresponding catalogue. For star-forming galaxies (SFGs), our results show excellent consistency with previous studies in terms of the star formation main sequence and the size-mass relation, demonstrating the robustness of our stellar mass and SFR measurements. For spatially resolved profiles, we find that at higher redshifts ($z>2.5$), the median radial profile of $Σ_{\rm SFR}$ is nearly parallel to but slightly steeper than that of $Σ_*$. This results in mildly negative gradients in the specific SFR (sSFR) profiles across all stellar mass bins considered. These findings indicate that galaxies at $z>2.5$ cannot grow in size via only in-situ star formation, challenging the understanding of galaxy size evolution beyond the cosmic noon. In contrast, at $z<2.0$, the sSFR profiles transition to exhibit more and more positive gradients at lower redshifts, consistent with an inside-out growth scenario where star formation preferentially expands the galactic outskirts. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_01684 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Transition from Outside-in to Inside-Out at $z\sim 2$: Evidence from Radial Profiles of Specific Star Formation Rate based on JWST/HST Song, Jie Wang, Enci Jia, Cheng Lyu, Cheqiu Chen, Yangyao Wang, Jinyang Li, Fujia Ding, Weiyu Fang, Guanwen Kong, Xu Astrophysics of Galaxies By combining high-resolution observations from JWST and HST, we have measured the stellar masses, star formation rates (SFRs), and multi-wavelength morphologies of galaxies in the CANDELS fields. Furthermore, based on rest-frame 1 $μ$m morphologies, we have derived spatially resolved stellar mass and SFR surface density ($Σ_*$ and $Σ_{\rm SFR}$) profiles for 46,313 galaxies with reliable structural measurements at $0<z<4$ and $\log(M_\ast /M_{\odot})>8$, and provide the corresponding catalogue. For star-forming galaxies (SFGs), our results show excellent consistency with previous studies in terms of the star formation main sequence and the size-mass relation, demonstrating the robustness of our stellar mass and SFR measurements. For spatially resolved profiles, we find that at higher redshifts ($z>2.5$), the median radial profile of $Σ_{\rm SFR}$ is nearly parallel to but slightly steeper than that of $Σ_*$. This results in mildly negative gradients in the specific SFR (sSFR) profiles across all stellar mass bins considered. These findings indicate that galaxies at $z>2.5$ cannot grow in size via only in-situ star formation, challenging the understanding of galaxy size evolution beyond the cosmic noon. In contrast, at $z<2.0$, the sSFR profiles transition to exhibit more and more positive gradients at lower redshifts, consistent with an inside-out growth scenario where star formation preferentially expands the galactic outskirts. |
| title | Transition from Outside-in to Inside-Out at $z\sim 2$: Evidence from Radial Profiles of Specific Star Formation Rate based on JWST/HST |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2512.01684 |