Spatially Resolved Nebular-Stellar Reddening with JWST/NIRISS
利用JWST/NIRISS的空间分辨星云-恒星红化
Peter J. Watson, Benedetta Vulcani, Tommaso Treu, Ayan Acharyya, Marc Rafelski, Anahita Alavi, Matthew Hayes, Keunho Kim, Faezeh Manesh, Claudia Scarlata
AI总结 利用JWST/NIRISS数据对1.0<z<2.4的星系进行亚kpc尺度分析,通过多区域拟合提取Hα和Hβ发射线图,发现星云与连续谱红化关系与局部星暴星系一致,并推导出微分红化与SFR和恒星质量的经验标定。
Comments 17 pages, 19 figures (including appendices), submitted to A&A
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准确测定星系内的尘埃消光对于推导恒星形成率(SFR)等关键物理性质至关重要。我们利用GLASS-JWST ERS计划中的JWST/NIRISS数据,研究并表征了$1.0<z<2.4$星系在亚kpc尺度上的恒星和星云红化。我们采用多区域拟合方法,提取了99个单独星系的高质量H$\alpha$和H$\beta$发射线图,其恒星质量范围为$7.0<\log_{10}(M_*/\mathrm{M}_{\odot})<10.5$。我们没有发现巴尔默减缩(H$\alpha$/H$\beta$)低于Case B复合固有极限的证据,超出观测不确定性的预期变化。我们再现了巴尔默减缩与总恒星质量的局部相关性,并在按红移分割样本时未发现可测量的差异,在$\log_{10}(M_*/\mathrm{M}_{\odot})\lesssim8.5$以下消光可忽略。类似地,星云和连续谱红化的最佳拟合关系与局部星暴星系的关系相同,即$E(B-V)_{\mathrm{SED}} = (0.46\pm0.02)E(B-V)_{\mathrm{neb}}$,共同表明在$z\lesssim2.4$范围内星系内的尘埃几何结构没有显著演化。我们推导了微分星云-恒星红化与SED导出的恒星形成率(SFR)和恒星质量之间的最佳拟合线性关系,发现两者均具有统计显著性。我们利用空间分辨测量结果,推导了分辨微分红化与SFR面密度的经验标定。这些将为更高红移(如未来Roman棱栅观测)中无法获取巴尔默线的空间分辨科学提供关键的尘埃消光校正。
An accurate determination of the dust attenuation within galaxies is essential to derive key physical properties such as the star formation rate (SFR). We present an analysis using the JWST/NIRISS data from the GLASS-JWST ERS programme to investigate and characterise the stellar and nebular reddening of galaxies at $1.0<z<2.4$, down to the sub-kpc scale. We use a multiregion fitting method to extract high-quality H$α$ and H$β$ emission line maps for 99 individual galaxies across a stellar mass range $7.0<\log_{10}(M_*/\mathrm{M}_{\odot})<10.5$. We find no evidence for ratios of the Balmer decrement (H$α$/H$β$) below the intrinsic limit for Case B recombination, beyond the expected variation from observational uncertainties. We reproduce the local correlation between the Balmer decrement and total stellar mass, and find no measurable difference when splitting the sample by redshift, with negligible attenuation below $\log_{10}(M_*/\mathrm{M}_{\odot})\lesssim8.5$. Similarly, the best-fit relation between the nebular and continuum reddening follows the same relation as in local starburst galaxies, $E(B-V)_{\mathrm{SED}} = (0.46\pm0.02)E(B-V)_{\mathrm{neb}}$, together indicating no significant evolution in the dust geometry within galaxies out to $z\lesssim2.4$. We derive best-fit linear relations between the differential nebular-stellar reddening and the SED-derived star formation rate (SFR) and stellar mass, finding statistically significant relations for both quantities. We use our spatially-resolved measurements to derive an empirical calibration between the resolved differential reddening, and the SFR surface density. These will enable crucial dust attenuation corrections for spatially-resolved science at higher redshifts where the Balmer lines are inaccessible, such as with future Roman grism observations.