论文标题
最贫穷的星系中的星星和气体I：SBS 0335-052E的COS和MUSE观察
Stars and gas in the most metal-poor galaxies I: COS and MUSE observations of SBS 0335-052E
论文作者
论文摘要
SBS 0335-052E最接近的最接近金属贫困的Starburst-Dwarf星系中，是整合的Nebular HE IIλ4686发射中最发光的。这使其成为测试光谱合成模型和光谱解释工具的独特目标，该工具将用于解释原始星系的未来REST框架紫外线观测。以前尝试复制其IIλ4686发射发光度的尝试发现，X射线源，冲击和单狼射线星并不是He II Iromization预算的主要贡献者。而且，只有无金属的单旋转恒星或具有顶部IMF和非机质低金属性的二进制恒星才能再现它。我们提出了新的紫外线（COS）和光学（缪斯）光谱，该光谱将SBS 0335-052E中的四个超级明星簇的光整合在一起。 Nebular He II，[C III]，C III]，C IV和O III] UV发射线，其等效宽度在1.7至5Å之间，并且检测到A C IVλλ1548，1551 p-cygni喜欢的轮廓。最近的极度不良冲击 +前体模型和二进制模型无法再现观察到的光发射线比。我们使用不同的紫外线和光学可观察物来测试具有单个非旋转星的恒星形成模型，这些恒星占恒星非常巨大的恒星，因为存在蓝光OVλ1371吸收。同时拟合所有高电离紫外线线的通量，需要非机质低的金属性。拟合C IVλλ1548，1551的P-Cygni + Nebular成分，自恒星形成开始以来，不会限制恒星金属性和时间。我们获得了12+log（O/h）= 7.45 \ pm0.04和log（c/o）= -0.45（+0.03）（-0.04）（-0.04）。模型测试将受益于较高的空间分辨率紫外线和星系的光谱。
Among the nearest most metal-poor starburst-dwarf galaxies known, SBS 0335-052E is the most luminous in integrated nebular He II λ4686 emission. This makes it a unique target to test spectral synthesis models and spectral interpretation tools of the kind that will be used to interpret future rest-frame UV observations of primeval galaxies. Previous attempts to reproduce its He II λ4686 emission luminosity found that X-ray sources, shocks, and single Wolf-Rayet stars are not main contributors to the He II-ionizing budget; and that only metal-free single rotating stars or binary stars with a top-heavy IMF and an unphysically-low metallicity can reproduce it. We present new UV (COS) and optical (MUSE) spectra which integrate the light of four super star clusters in SBS 0335-052E. Nebular He II, [C III], C III], C IV, and O III] UV emission lines with equivalent widths between 1.7 and 5 Å, and a C IV λλ1548, 1551 P-Cygni like profile are detected. Recent extremely-metal poor shock + precursor models and binary models fail to reproduce the observed optical emission-line ratios. We use different sets of UV and optical observables to test models of constant star formation with single non-rotating stars which account for very massive stars, as blueshifted O V λ1371 absorption is present. Simultaneously fitting the fluxes of all high-ionization UV lines requires an unphysically-low metallicity. Fitting the P-Cygni like + nebular components of C IV λλ1548, 1551 does not constrain the stellar metallicity and time since the beginning of star formation. We obtain 12+log(O/H)=7.45\pm0.04 and log(C/O)=-0.45(+0.03)(-0.04) for the galaxy. Model-testing would benefit from higher spatial resolution UV and optical spectroscopy of the galaxy.
