论文标题
高清和灰尘发射的气体和星形在强烈的星系中
Gas and Star Formation from HD and Dust Emission in a Strongly Lensed Galaxy
论文作者
论文摘要
高红移星系的分子气体含量是高度抢手的特性。但是，H $ _2 $在大多数环境中都无法直接观察，因此其质量是通过其他发射线（例如CO，CO，[CI]，[CII]）或通过气盘比进行探测的。这些方法中的每一个都取决于几个假设，并且最好并行使用。在这项工作中，我们通过观察强烈镜头的$ z = 5.656 $ Galaxy SPT0346-52与Alma一起观察氢氘（HD）发射，将额外的分子气体示踪剂扩展到了高红移研究。虽然未检测到未检测到的HD（1-0）排放，但我们能够对$ \ rm m_ {H_2} <6.4 \ times10^{11} M _ {\ odot} $的气体质量上限。这是为了找到$ \ rm l'_ {CO} $转换系数的限制，为$ \rmα_{CO} <5.8 $ m $ _ {\ odot} $（k km s $ s $^{ - 1} $ pc $^2 $^2 $^2 $^{ - 1} $。此外，我们迄今为止构建了此源的最完整的光谱能量分布（SED），并使用嵌套采样代码进行多节点的单个修改后的黑体，从而产生最佳拟合的灰尘质量$ \ rm \ rm m_ {dust = 10^{8.92发射光谱索引$β= 1.81 \ pm0.03 $，而星形构成率$ \ rm sfr = 3800 \ pm100 $ m $ _ {\ odot} $ egar $^$^{ - 1} $。使用连续通量密度估算源的总气体质量，我们发现$ \ rm m_ {h_2} <2.4 \ times10^{11} $ m $ _ {\ odot} $，假设具有亚阳光金属性。这意味着$ \rmα_{co} <2.2 $的CO转换因子是在类似MW的星系和Starbursts的标准值之间。这些特性证实SPT0346-52是富含汽油的星系的巨大的星空。
The molecular gas content of high-redshift galaxies is a highly sought-after property. However, H$_2$ is not directly observable in most environments, so its mass is probed through other emission lines (e.g., CO, [CI], [CII]), or through a gas-to-dust ratio. Each of these methods depends on several assumptions, and are best used in parallel. In this work, we extend an additional molecular gas tracer to high-redshift studies by observing hydrogen deuteride (HD) emission in the strongly lensed $z=5.656$ galaxy SPT0346-52 with ALMA. While no HD(1-0) emission is detected, we are able to place an upper limit on the gas mass of $\rm M_{H_2}<6.4\times10^{11} M_{\odot}$. This is used to find a limit on the $\rm L'_{CO}$ conversion factor of $\rmα_{CO}<5.8$ M$_{\odot}$(K km s$^{-1}$ pc$^2$)$^{-1}$. In addition, we construct the most complete spectral energy distribution (SED) of this source to date, and fit it with a single-temperature modified blackbody using the nested sampling code MultiNest, yielding a best-fit dust mass $\rm M_{dust}=10^{8.92\pm0.02}$ M$_{\odot}$, dust temperature $78.6\pm0.5$ K, dust emissivity spectral index $β=1.81\pm0.03$, and star formation rate $\rm SFR=3800\pm100$ M$_{\odot}$ year$^{-1}$. Using the continuum flux densities to estimate the total gas mass of the source, we find $\rm M_{H_2}<2.4\times10^{11}$ M$_{\odot}$, assuming sub-solar metallicity. This implies a CO conversion factor of $\rm α_{CO}<2.2$, which is between the standard values for MW-like galaxies and starbursts. These properties confirm that SPT0346-52 is a heavily starbursting, gas rich galaxy.
