Detection of [O iii] at z ∼ 3: A Galaxy Above the Main Sequence, Rapidly Assembling Its Stellar Mass
Detection of [O iii] at z ∼ 3: A Galaxy Above the Main Sequence, Rapidly Assembling Its Stellar Mass
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DOI：
10.3847/1538-4357/aab354
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发表时间：
2018-03
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通讯作者：
A. Vishwas;C. Ferkinhoff;T. Nikola;S. Parshley;J. Schoenwald;G. Stacey;S. Higdon;J. Higdon;A. Weiss;R. Güsten;K. Menten
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作者：
A. Vishwas;C. Ferkinhoff;T. Nikola;S. Parshley;J. Schoenwald;G. Stacey;S. Higdon;J. Higdon;A. Weiss;R. Güsten;K. Menten
我们利用阿塔卡马探路者实验望远镜（APEX）的第二代红移（z）和早期宇宙光谱仪（ZEUS-2）探测到了一个强透镜候选星系H-ATLAS J113526.3-014605（以下简称G12v2.43）在z = 3.127处的远红外精细结构[O iii] 88 μm谱线的明亮发射。这只是第五次探测到这条来自亚毫米星系的远红外线。观测到的[O iii]光度为7.1 × 109 L，可能来自大质量恒星周围的H ii区域，而支持电离所需的莱曼连续谱光子的数量表明存在（1.2-5.2）× 106当量的O 5.5或更高的恒星，其中μ是透镜放大因子。观测到的谱线光度也需要电离气体的最小质量为102 × 108 M，即估计的总分子气体质量6 × 1010 M的0.33%。我们编译多波段测光跟踪静止帧紫外到毫米连续辐射，以进一步限制这个尘埃高红移，恒星形成星系的属性。通过SED模型，我们发现G12v2.43正在以916 M <$yr−1的速度形成恒星，并且已经有8 × 1010 M <$yr的恒星质量。我们还将当前恒星暴增的年龄限制在百万年，使G12v2.43成为一个富含气体的星系，位于恒星形成的主序带上方，z = 3，经历了一个生长的井喷，它可能位于主序带上，推导出的气体耗尽时间尺度为1.66亿年。
We detect bright emission in the far-infrared (far-IR) fine structure [O iii] 88 μm line from a strong lensing candidate galaxy, H-ATLAS J113526.3-014605, hereafter G12v2.43, at z = 3.127, using the second-generation Redshift (z) and Early Universe Spectrometer (ZEUS-2) at the Atacama Pathfinder Experiment Telescope (APEX). This is only the fifth detection of this far-IR line from a submillimeter galaxy at the epoch of galaxy assembly. The observed [O iii] luminosity of 7.1 × 109 L⊙ likely arises from H ii regions around massive stars, and the amount of Lyman continuum photons required to support the ionization indicate the presence of (1.2–5.2) × 106 equivalent O5.5 or higher stars, where μ would be the lensing magnification factor. The observed line luminosity also requires a minimum mass of ∼2 × 108 M⊙ in ionized gas, that is 0.33% of the estimated total molecular gas mass of 6 × 1010 M⊙. We compile multi-band photometry tracing rest-frame ultraviolet to millimeter continuum emission to further constrain the properties of this dusty high-redshift, star-forming galaxy. Via SED modeling we find G12v2.43 is forming stars at a rate of 916 M⊙ yr−1 and already has a stellar mass of 8 × 1010 M⊙. We also constrain the age of the current starburst to be Myr, making G12v2.43 a gas-rich galaxy lying above the star-forming main sequence at z ∼ 3, undergoing a growth spurt, and it could be on the main sequence within the derived gas depletion timescale of ∼66 Myr.