论文标题
紫外线Z〜3-7星系中电离光子的产生
The production of ionizing photons in UV-faint z~3-7 galaxies
论文作者
论文摘要
从紫外线素食的早期星系中产生和逃脱光子的人口统计学是发现重新离子的主要驱动因素是未知的关键。随着JWST的出现，最终可以观察到从单个sub-l $^*$ z> 3星系中的其余帧光学轴向发射，以测量电离光子的产生，$ξ_\ mathrm {ion} $。在这里，我们研究了370 Z〜3-7个星系的样本-23 <m $ _ \ Mathrm {uv} $ <-15.5（中间M $ _ \ Mathrm {uv} \ $ -18），带有深层多频段HST HST和JWST/NIRCAM PHOTMOMMOMETRY，覆盖RESS -uss -us的JWST/Nircam Photommet just to the Glass to the glass to the glass to the Glasse to the Glassers。我们的样本包括102个星系，并在缪斯光谱学中检测到lyman-alpha排放。我们使用从NIRCAM光度法推断出的H-Alpha通量来估计不会逃脱这些星系的电离光子的生产速率$ξ_\ MATHRM {ion}（1-F_ \ MATHRM {ESC}）$。我们发现中位数$ \ log_ {10}ξ_\ mathrm {ion}（1-f_ \ mathrm {cess}）= 25.33 \ pm 0.47 $，具有广泛的内在散点0.42 DEX，暗示我们在我们的UV-Faint样品中具有广泛的星系属性和age。用Lyman-Alpha检测到的星系具有〜0.1 DEX更高$ξ_\ MathRM {ion}（1-F_ \ Mathrm {Esc}）$，这是通过其较高的H-Alpha EW分布来解释的，这意味着年轻的年龄，更高的SSFR，因此SSFR和更高的O/B星。我们发现，随着H-Alpha eW的增加，降低紫外线的光度并降低了UV斜坡，增加了$ξ_\ MathRM {ion}（1-F_ \ MathRM {ESC}）$的重大趋势，暗示在年轻的低金属金属中增强电离光子的产生。我们没有发现基于其样品的光度特性，即使在Lyman-Alpha选定的星系中，我们的样品中没有非常高电离的逃生分数（$ f_ \ mathrm {esc} $> 0.5）的源没有明显的证据。这项工作表明，考虑到$ξ_\ mathrm {ion} $的完整分布在星系属性中对于评估重新离子的主要驱动因素很重要。
The demographics of the production and escape of ionizing photons from UV-faint early galaxies is a key unknown in discovering the primary drivers of reionization. With the advent of JWST it is finally possible to observe the rest-frame optical nebular emission from individual sub-L$^*$ z>3 galaxies to measure the production of ionizing photons, $ξ_\mathrm{ion}$. Here we study a sample of 370 z~3-7 galaxies spanning -23 <M$_\mathrm{UV}$ < -15.5 (median M$_\mathrm{UV}\approx$ -18) with deep multi-band HST and JWST/NIRCam photometry covering the rest-UV to optical from the GLASS and UNCOVER JWST surveys. Our sample includes 102 galaxies with Lyman-alpha emission detected in MUSE spectroscopy. We use H-alpha fluxes inferred from NIRCam photometry to estimate the production rate of ionizing photons which do not escape these galaxies $ξ_\mathrm{ion}(1-f_\mathrm{esc})$. We find median $\log_{10}ξ_\mathrm{ion}(1-f_\mathrm{esc})=25.33\pm 0.47$, with a broad intrinsic scatter 0.42 dex, implying a broad range of galaxy properties and ages in our UV-faint sample. Galaxies detected with Lyman-alpha have ~0.1 dex higher $ξ_\mathrm{ion}(1-f_\mathrm{esc})$, which is explained by their higher H-alpha EW distribution, implying younger ages, higher sSFR and thus more O/B stars. We find significant trends of increasing $ξ_\mathrm{ion}(1-f_\mathrm{esc})$ with increasing H-alpha EW, decreasing UV luminosity, and decreasing UV slope, implying the production of ionizing photons is enhanced in young, low metallicity galaxies. We find no significant evidence for sources with very high ionizing escape fraction ($f_\mathrm{esc}$>0.5) in our sample, based on their photometric properties, even amongst the Lyman-alpha selected galaxies. This work demonstrates that considering the full distribution of $ξ_\mathrm{ion}$ across galaxy properties is important for assessing the primary drivers of reionization.
