论文标题
黑暗能源调查的低金属星系
Low Metallicity Galaxies from the Dark Energy Survey
论文作者
论文摘要
我们提出了从黑暗能源调查（DES）中的5,000平方度的358个蓝色紧凑型矮星系（BCD）的新选择，以及68个物体的子样本的光谱随访。对于具有深光谱的34个对象的子样本，我们使用Auroral [\ oiii] $λ$ 4363排放线通过直接t $ _e $方法测量金属性。这些BCD的平均氧气丰度为12+log（O/h）= 7.8，恒星质量在10 $^7 $至10 $^8 $^8 $ m $ _ \ odot $和特定的星形地层之间，$ \ sim $ \ sim $ 10 $^{ - 9} $ to 10 $^{ - 7} $^{ - 7} $ yr $^$^$^{ - 1} $^{-1} $} { - 1}。我们将BCD的位置与从局部体积遗产样本得出的质量金属性（M-Z）和亮度金属关系（L-Z）关系进行比较。我们发现有关M-Z关系的散射小于L-Z关系的散射。我们确定了来自M-Z和L-Z关系的偏移之间的相关性，这是由于金属贫困流入的贡献所致。最后，我们探讨了星系探测的质量范围内质量金属质量-SFR基本平面的有效性。我们发现，具有恒星质量的BCD小于$ 10^{8} $ m $ _ {\ odot} $不遵循基本平面的外推。该结果表明，流入和流出之间的平衡以外的其他机制可能在调节M-Z-SFR空间中低质量星系的位置时起作用。
We present a new selection of 358 blue compact dwarf galaxies (BCDs) from 5,000 square degrees in the Dark Energy Survey (DES), and the spectroscopic follow-up of a subsample of 68 objects. For the subsample of 34 objects with deep spectra, we measure the metallicity via the direct T$_e$ method using the auroral [\oiii]$λ$ 4363 emission line. These BCDs have an average oxygen abundance of 12+log(O/H)= 7.8, with stellar masses between 10$^7$ to 10$^8$ M$_\odot$ and specific star formation rates between $\sim$ 10$^{-9}$ to 10$^{-7}$ yr$^{-1}$. We compare the position of our BCDs with the Mass-metallicity (M-Z) and Luminosity-metallicity (L-Z) relation derived from the Local Volume Legacy sample. We find the scatter about the M-Z relation is smaller than the scatter about the L-Z relation. We identify a correlation between the offsets from the M-Z and L-Z relation that we suggest is due to the contribution of metal-poor inflows. Finally, we explore the validity of the mass-metallicity-SFR fundamental plane in the mass range probed by our galaxies. We find that BCDs with stellar masses smaller than $10^{8}$M$_{\odot}$ do not follow the extrapolation of the fundamental plane. This result suggests that mechanisms other than the balance between inflows and outflows may be at play in regulating the position of low mass galaxies in the M-Z-SFR space.
