论文标题
在$ z = 7-11 $ in JWST/NIRCAM成像中搜索极蓝色的紫外线连续斜率：对早期星系中恒星金属性和电离光子逃生的影响
Searching for Extremely Blue UV Continuum Slopes at $z=7-11$ in JWST/NIRCam Imaging: Implications for Stellar Metallicity and Ionizing Photon Escape in Early Galaxies
论文作者
论文摘要
星系的紫外线（UV）连续斜率（$ 〜f_λ \Proptoλ^β$）对各种特性敏感，从恒星种群的金属性和年龄到整个银河系的尘埃衰减。非常关注的重点是识别具有非常蓝色的紫外线斜坡（$β<-3 $）的电离时代星系。这种系统不仅提供了低金属性星的路标，而且还可以确定可能从其HII区域泄漏光子的星系，因为这样的蓝色紫外线需要减小Nebular Continuum的红色效果。在本文中，我们介绍了EGS领域的JWST/NIRCAM成像中搜索具有非常蓝色的紫外线的电离时代星系。我们表征了$ 〜z \ simeq7-11〜 $星系的大型样本的UV斜率，找到了$ 〜β = -2.0 $的中位数。 Two lower luminosity (M$_{\rm{UV}}\simeq-19.5$) and lower stellar mass (6-10$\times10^7$M$_\odot$) systems exhibit extremely blue UV slopes ($β=-2.9~$to$~-3.1$) and rest-optical photometry indicating weak nebular line emission.每个系统都非常紧凑（r $ _e \ Lessim $ 260pc），具有很高的星形速率表面密度。我们用一套Beagle模型对SED进行建模，这些模型具有不同水平的电离光子逃逸水平。 SED不能用我们的信托（f $ _ {\ rm {esc，hii}} $ = 0）或alpha-enhanced（z $ _ \ star <z _ {\ rm {ism {ism}} $）模型来复制。蓝色紫外线和弱的卵形发射的组合是通过具有显着电离光子从HII区域逃脱的模型（f $ _ {\ rm {cess，hii}} $ = 0.5-0.8）和极低的金色巨大星星（z $ _ \ star $ = 0.01-01-06Z $ _____________________________________________________这些星系的发现突出了JWST在Reionization-ers时代中识别大量候选莱曼连续体泄漏星系的潜力，并表明低金属性恒星种群在矮人的星系中可能很常见，价格为$ z> 7 $。
The ultraviolet (UV) continuum slope ($β~$where$~f_λ\proptoλ^β$) of galaxies is sensitive to a variety of properties, from the metallicity and age of the stellar population to dust attenuation throughout the galaxy. Considerable attention has focused on identifying reionization-era galaxies with very blue UV slopes ($β<-3$). Not only do such systems provide a signpost of low-metallicity stars, but they also identify galaxies likely to leak ionizing photons from their HII regions as such blue UV slopes require the reddening effect of nebular continuum to be diminished. In this paper we present a search for reionization-era galaxies with very blue UV colors in recent JWST/NIRCam imaging of the EGS field. We characterize UV slopes for a large sample of$~z\simeq7-11~$galaxies, finding a median of$~β=-2.0$. Two lower luminosity (M$_{\rm{UV}}\simeq-19.5$) and lower stellar mass (6-10$\times10^7$M$_\odot$) systems exhibit extremely blue UV slopes ($β=-2.9~$to$~-3.1$) and rest-optical photometry indicating weak nebular line emission. Each system is very compact (r$_e\lesssim$260pc) with very high star-formation-rate surface densities. We model the SEDs with a suite of BEAGLE models with varying levels of ionizing photon escape. The SEDs cannot be reproduced with our fiducial (f$_{\rm{esc,HII}}$=0) or alpha-enhanced (Z$_\star<Z_{\rm{ISM}}$) models. The combined blue UV slopes and weak nebular emission are best-fit by models with significant ionizing photon escape from HII regions (f$_{\rm{esc,HII}}$=0.5-0.8) and extremely low-metallicity massive stars (Z$_\star$=0.01-0.06Z$_\odot$). The discovery of these galaxies highlights the potential for JWST to identify large numbers of candidate Lyman Continuum leaking galaxies in the reionization-era and suggests low-metallicity stellar populations may be common in dwarf galaxies at $z>7$.
