arXiv 2512.024402025-12-03astro-ph.GA

从HST+JWST观测到z=2.5的紫外到近红外颜色梯度的演化与质量依赖性

Evolution and Mass Dependence of UV-to-near-IR Color Gradients up to z=2.5 from HST+JWST

Universiteit Gent（根特大学）；University of Michigan（密歇根大学）；University of Copenhagen（哥本哈根大学）；Université de Liège（列日大学）；University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）；University of Bath（巴斯大学）

Marco Martorano, Arjen van der Wel, Andrea Gebek, Maarten Baes, Eric F. Bell, Gabriel Brammer, Sharon E. Meidt, Angelos Nersesian, Katherine Whitaker, Stijn Wuyts

备注：: Accepted for publication on A&A; 12 pages with 8 figures, 4 pages appendix with 3 figures
发表信息：: A&A 705, A236 (2026)
DOI：: 10.1051/0004-6361/202555974

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AI总结：

研究利用HST和JWST数据，分析z=2.5内星系颜色梯度随红移和质量的变化，发现恒星形成星系颜色梯度与尘埃消光相关，而静止星系则受恒星群体梯度影响。

摘要：

我们呈现了0.5<z<2.5范围内星系径向颜色梯度（以静止框架的U-V和V-J）的红移演化，并研究其起源和对恒星质量的依赖性。我们从公开的JWST/NIRCam选定目录中选取约10200个恒星质量M*>10^9.5 M☉的星系。利用二维Sérsic分布拟合以考虑PSF展宽，我们对HST和JWST/NIRCam光度数据进行空间解析SED拟合，从而在2R_e,F444W范围内获得准确的静止框架U-V和V-J颜色梯度。恒星形成星系通常表现出强烈的负V-J颜色梯度，且强烈依赖于质量和红移。对于质量大于10^10.5 M☉的恒星形成星系（z>1.5），V-J颜色在有效半径内比外部大约0.5个星等更红。我们发现，在所有红移和整个恒星质量范围内，V-J梯度强烈相关于全局消光（A_V），表明它们主要追踪尘埃消光梯度。边缘星系在所有z下更红且梯度更强，尽管相关性在更高z下减弱。相比之下，静止星系群体的U-V和V-J颜色梯度较弱（从约-0.1到约-0.2个星等），但显著，且对恒星质量、红移或轴比几乎没有依赖性。其含义是静止星系必须大部分透明，具有低A_V，颜色梯度主要归因于恒星群体梯度。

英文摘要：

We present the redshift evolution of radial color gradients (in rest-frame ${\textit{U}} - {\textit{V}}$ and ${\textit{V}} - {\textit{J}}$) for galaxies in the range $0.5<$ z $<2.5$ and investigate their origin and dependence on stellar mass. We select $\sim 10,200$ galaxies with stellar masses $M_\star>10^{9.5}~{\text{M}}_\odot$ from publicly available JWST/NIRCam-selected catalogs. Using 2D Sérsic profile fits to account for PSF broadening, we perform spatially resolved SED fitting on HST and JWST/NIRCam photometry retrieving accurate rest-frame ${\textit{U}} - {\textit{V}}$ and ${\textit{V}} - {\textit{J}}$ color gradients within 2$R_\text{e, F444W}$. Star-forming galaxies generally exhibit negative ${\textit{V}} - {\textit{J}}$ color gradients that are strongly mass and redshift dependent. For massive star-forming galaxies ($M_\star>10^{10.5}~{\text{M}}_\odot$) at $z>1.5$ ${\textit{V}} - {\textit{J}}$ colors are $\approx 0.5$ mag redder within the effective radius than outside, on average. We find that, at all redshifts and across the entire stellar mass range, ${\textit{V}} - {\textit{J}}$ gradients strongly correlate with global attenuation ($A_V$), suggesting that they predominantly trace dust attenuation gradients. Edge-on galaxies are redder and have stronger gradients at all $z$, although the correlation weakens at higher $z$. The ${\textit{U}} - {\textit{V}}$ and ${\textit{V}} - {\textit{J}}$ color gradients in the quiescent galaxy population, in contrast, are weakly negative (from $\approx -0.1$ to $\approx- 0.2$ mag), though significant, and show little or no dependence on stellar mass, redshift or axis ratio. The implication is that quiescent galaxies must be largely transparent, with low $A_V$, and color gradients mostly attributable to stellar population gradients.

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