NIR Spectroscopy of Star-Forming Galaxies at z 1.4 with Subaru/FMOS: The Mass-Metallicity Relation
NIR Spectroscopy of Star-Forming Galaxies at z 1.4 with Subaru/FMOS: The Mass-Metallicity Relation
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DOI：
10.1093/pasj/64.3.60
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发表时间：
2011-12
影响因子：
2.3
通讯作者：
K. Yabe;K. Ohta;F. Iwamuro;S. Yuma;M. Akiyama;N. Tamura;M. Kimura;N. Takato;Y. Moritani;Masanao Sumiyoshi;T. Maihara;J. Silverman;G. Dalton;I. Lewis;D. Bonfield;Hanshin Lee;E. Lake;E. MacAulay;F. Clarke
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作者：
K. Yabe;K. Ohta;F. Iwamuro;S. Yuma;M. Akiyama;N. Tamura;M. Kimura;N. Takato;Y. Moritani;Masanao Sumiyoshi;T. Maihara;J. Silverman;G. Dalton;I. Lewis;D. Bonfield;Hanshin Lee;E. Lake;E. MacAulay;F. Clarke
我们在斯巴鲁望远镜上用FMOS对z = 1.4的恒星形成星系进行了近红外光谱观测。我们在SXDS/UDS场中观测了K波段的选择星系，其K = 23.9等，1.2等，1.6等，M = 10 9：5等，F（H）= 10 16尔格·1 cm 2 ; 71天体，样品中有明显的H探测。对于这些物体，不包括可能的活动星系核，确定从BPT图，气相金属丰度得到的[NII]/H的线比。样本被分成三个恒星质量仓，光谱被堆叠在每个恒星质量仓中。在z = 1.4处获得的质量-金属丰度关系位于z = 0.8和z = 2.2之间。我们将内禀散射限制为-0.1dex，或者在z-1.4的质量-金属丰度关系中更大;在更高的红移下散射可能更大。我们发现，偏离质量-金属丰度关系的趋势取决于SFR（恒星形成率）和半光半径：具有较高SFR和较大半光半径的星系在给定恒星质量下显示出较低的金属丰度。这种趋势的一种可能的情况是IGM或通过合并事件产生的原始气体的注入。在z = 0.1处，我们的数据点比基本金属丰度关系（FMR）有更大的分散性，平均金属丰度稍微偏离FMR。在z �3 t oz � 0.1处的质量-金属丰度关系的汇编表明，它们从z �3 t oz � 0平滑地演变，而不会改变形状，除了z � 0处的大质量部分。
We present near-infrared spectroscopic observations of star-forming galaxies at z � 1.4 with FMOS on the Subaru Telescope. We observed K-band selected galaxies in the SXDS/UDS fields with K � 23.9mag, 1.2 � zph � 1.6, M� � 10 9:5 Mˇ, andexpectedF(H˛) � 10 � 16 ergs � 1 cm � 2 ; 71objectsin the sample havesignificantdetections of H˛. For these objects, excluding possible AGNs, identified from the BPT diagram, gas-phase metallicities were obtained from the [NII]/H˛ line ratio. The sample is split into three stellar-mass bins, and the spectra are stacked in each stellar-mass bin. The mass‐metallicity relation obtained at z � 1.4 is located between those at z � 0.8 and z � 2.2. We constrain the intrinsic scatter to be � 0.1dex, or larger in the mass‐metallicity relation at z � 1.4; the scatter may be larger at higher redshifts. We found trends that the deviation from the mass‐metallicity relation depends on the SFR (Star-formation rate) and the half light radius: Galaxies with higher SFR and larger half light radii show lower metallicities at a given stellar mass. One possible scenario for the trends is the infall of pristine gas accreted from IGM, or through merger events. Our data points show larger scatter than the fundamental metallicity relation (FMR) at z � 0.1, and the averagemetallicities slightly deviate fromthe FMR. The compilationof the mass‐ metallicity relations at z � 3t oz � 0.1 shows that they evolve smoothly from z � 3t oz � 0 without changing the shape so much, except for the massive part at z � 0.