AI 中文总结
本研究针对高红移星系，利用适配其条件的模拟发现红外SED行为由光度密度主导，据此提出校正因子，可从ALMA亚毫米测量值修正得到总红外光度，用于估算恒星形成率。
AI 中文摘要
确定极高红移星系的总红外光度，对估算尘埃密集环境中的恒星形成率至关重要，但这一工作颇具挑战性：最灵敏的远红外天文台赫歇尔（Herschel）灵敏度有限，其最深测量值还受混淆噪声影响，因此这类光度测定很大程度上依赖阿塔卡马大型毫米波/亚毫米波阵列（ALMA）在毫米波和/或亚毫米波段的观测，而该波段仅能采样星系光谱能量分布（SED）的长波部分。传统上，人们会用修正黑体模型拟合这些测量值来估算光度，但该方法未包含暖尘埃的中红外辐射；有证据表明，极高红移星系的中红外成分相对本地星系可能更强，因此需对修正黑体光度应用校正因子以推导总红外光度。本研究采用适配高红移星系典型条件的模拟来分析红外SED，发现红外SED的不同行为由单一关键物理参数——光度密度主导，这使我们能通用地估算缺失的中红外光度校正值。研究发现，多数情况下采用约1.6-1.7（0.2 dex）的校正因子较为合适；对于红移z>4、光度>10^12 L☉的高红移最亮星系，需采用更大的校正因子，范围约1.75-1.85（~0.25 dex），最高可达2（0.3 dex），这些校正是基于总红外光度估算恒星形成率所必需的。
英文摘要
Determining total infrared luminosities for very high redshift galaxies is important to estimate the rate of star formation in heavily dust-embedded environments. It is also challenging because the most sensitive far infrared observatory, Herschel, was limited in sensitivity and its deepest measurements are subject to confusion noise. Thus, these determinations largely depend on ALMA, observing in the mm- and/or submm-wavelengths, which sample only the long-wavelength part of the spectral energy distributions (SEDs). Luminosities are conventionally estimated with modified blackbody fits to these measurements, but do not include the emission in the mid-infrared by warmer dust; there is evidence that this mid-IR component may be relatively strong in very high-redshift galaxies compared with local ones. A correction factor must be applied to the modified black body luminosities to derive the total infrared luminosity. We study infrared SEDs using simulations tuned to galactic conditions typical of high-z galaxies. We find that the different behaviors of infrared SEDs are dominated by a single key physical parameter, the luminosity density. This allows us to estimate the corrections for the missing mid-infrared luminosity in a general way. We find that a factor of ~ 1.6 - 1.7 (0.2 dex) is appropriate in most circumstances, with a larger factor of ~ 1.75 - 1.85 (~ 0.25 dex) up to 2 (0.3 dex) necessary for high redshift (z > 4) galaxies at the highest luminosities, > 10^{12} Lsun. These corrections are needed to estimate star formation rates based on total infrared luminosity.
Commentsaccepted by ApJ
