Measuring the Physical Conditions in High-redshift Star-forming Galaxies: Insights from KBSS-MOSFIRE
Measuring the Physical Conditions in High-redshift Star-forming Galaxies: Insights from KBSS-MOSFIRE
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测量高红移恒星形成星系的物理条件：KBSS-MOSFIRE 的见解
DOI：
10.3847/1538-4357/aae1a5
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
M. Pettini
中科院分区：
文献类型：
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作者：
A. Strom;C. Steidel;G. Rudie;R. Trainor;M. Pettini
我们使用光电离化模型来协调高z恒星形成星系的联合REST-UV-光学光谱，以自洽地推断来自凯克重子结构调查的∼150星系的气体化学、星云电离和激发条件，只使用它们的REST-光学星云光谱的观测。我们发现大多数z∼2-3KBSS星系是中等富氧的，四分位数范围在12+log(O/H)=8.29-8.56之间，并且具有显著的亚太阳铁丰度，四分位数范围[Fe/H]=[−0.79，−0.53]，这为高z星系中的超太阳O/Fe提供了额外的证据。模型推断的电离参数和N/O与常见的强线指数(如O_(32)和N_2O_2)有很强的相关性，后者表现出与河外局部H_II区相似的行为。相比之下，通常用于测量气相O/H比的诊断方法(如N_2和O_3N_2)显示出与气体中存在的氧气总量相对较大的散布，并且其行为与z∼0时观察到的不同。我们为使用R23测量典型高z星系中的O/H提供了一个新的定标，尽管它对相对富氧的星系最有用；联合使用O32和R23并不能产生更有效的定标。最后，我们考虑了整个星系样本的物理条件之间的内在关联的含义，并发现在高z星系中N/O随O/H变化的方式与局部H II区几乎相同。然而，在高Z星系中，我们没有发现电离参数与金属丰度(O/H或Fe/H)之间的强反相关，这是利用强线比推断氧丰度的主要依据之一。
We use photoionization models that are designed to reconcile the joint rest-UV-optical spectra of high-z star-forming galaxies to self-consistently infer the gas chemistry and nebular ionization and excitation conditions for ∼150 galaxies from the Keck Baryonic Structure Survey (KBSS), using only observations of their rest-optical nebular spectra. We find that the majority of z ∼ 2–3 KBSS galaxies are moderately O-rich, with an interquartile range in 12 + log(O/H) = 8.29–8.56, and have significantly sub-solar Fe enrichment, with an interquartile range of [Fe/H] = [−0.79, −0.53], which contributes additional evidence in favor of super-solar O/Fe in high-z galaxies. The model-inferred ionization parameters and N/O are strongly correlated with common strong-line indices (such as O32 and N2O2), with the latter exhibiting similar behavior to local extragalactic H ii regions. In contrast, diagnostics commonly used for measuring gas-phase O/H (such as N2 and O3N2) show relatively large scatter with the overall amount of oxygen present in the gas and behave differently than observed at z ∼ 0. We provide a new calibration for using R23 to measure O/H in typical high-z galaxies, although it is most useful for relatively O-rich galaxies; combining O32 and R23 does not yield a more effective calibration. Finally, we consider the implications for the intrinsic correlations between physical conditions across the galaxy sample and find that N/O varies with O/H in high-z galaxies in a manner that is almost identical to local H ii regions. However, we do not find a strong anti-correlation between ionization parameter and metallicity (O/H or Fe/H) in high-z galaxies, which is one of the principal bases for using strong-line ratios to infer oxygen abundance.
DOI：
10.1088/0004-637x/768/1/74
发表时间：
2012-11
期刊：
The Astrophysical Journal
影响因子：
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作者：
L. Tacconi;R. Neri;R. Genzel;F. Combes;A. Bolatto;M. Cooper;S. Wuyts;F. Bournaud;A. Burkert-
通讯作者：
L. Tacconi;R. Neri;R. Genzel;F. Combes;A. Bolatto;M. Cooper;S. Wuyts;F. Bournaud;A. Burkert-
DOI：
10.1088/0004-637x/799/2/209
发表时间：
2014-09
期刊：
The Astrophysical Journal
影响因子：
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作者：
E. Wisnioski;N. F. Schreiber;S. Wuyts;E. Wuyts;K. Bandara;D. Wilman;R. Genzel;R. Bender;R. Da
通讯作者：
E. Wisnioski;N. F. Schreiber;S. Wuyts;E. Wuyts;K. Bandara;D. Wilman;R. Genzel;R. Bender;R. Da