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arXiv 1707.00637astro-ph.GA
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在COSMOS场中对亚毫米星系的ALMA巡天:从能量平衡光谱能量分布模拟导出的物理性质

An ALMA survey of submillimetre galaxies in the COSMOS field: Physical properties derived from energy balance spectral energy distribution modelling

Oskari Miettinen, Ivan Delvecchio, Vernesa Smolčić, Manuel Aravena, Drew Brisbin, Alexander Karim, Benjamin Magnelli, Mladen Novak, Eva Schinnerer, Marcus Albre… 展开作者

Oskari Miettinen, Ivan Delvecchio, Vernesa Smolčić, Manuel Aravena, Drew Brisbin, Alexander Karim, Benjamin Magnelli, Mladen Novak, Eva Schinnerer, Marcus Albrecht, Hervé Aussel, Frank Bertoldi, Peter L. Capak, Caitlin M. Casey, Christopher C. Hayward, Olivier Ilbert, Huib T. Intema, Chunyan Jiang, Olivier Le Fèvre, Henry J. McCracken, Alejandra M. Muñoz Arancibia, Felipe Navarrete, Nelson D. Padilla, Dominik A. Riechers, Mara Salvato, Kimberly S. Scott, Kartik Sheth, Lidia A. M. Tasca

摘要:

我们确定的物理性质的样品SMG在COSMOS领域,预先选择在观测波长为$λ_{\rm obs}=1.1$ mm,并跟进在$λ_{\rm obs}=1.3$毫米与ALMA。我们使用MAGPHYS来拟合124个目标SMG的全色(紫外到无线电)SED,其中19.4%是光谱确认的。SED分析是通过使用$λ_{\rm obs}=1.3$ mm发射作为分子气体的示踪剂来估计SMG的气体质量来补充的。恒星质量、SFR、尘埃温度、尘埃和气体质量的样本中位数和第16 - 84百分位数范围分别为$\log(M_{\star}/{\rm M}_{\odot})=11.09^{+0.41}_{-0.53}$、${\rm SFR}=402^{+661}_{-233}$、${\rm M}_{\odot}~{\rm yr}^{-1}$、$T_{\rm dust}=39.7^{+9.7}_{-7.4}$ K、$\log(M_{\rm dust}/{\rm M}_{\odot})=9.01^{+0.20}_{-0.31}$和$\log(M_{\rm gas}/{\rm M}_{\odot})=11.34^{+0.20}_{-0.23}$。发现中值气尘比和气体分数分别为$120^{+73}_{-30}$和$0.62^{+0.27}_{-0.23}$。我们发现,57.3%的SMG位于恒星形成星系的主序列(MS)中,而41.9%的源位于MS之上,其系数大于3(一个源位于MS之下)。最大的3 GHz无线电尺寸在MS源中找到。那些在静止帧UV中出现不规则的SMG主要是星爆,而MS SMG大多是盘状的。与星爆相比,MS SMG的无线电发射尺寸更大,这可能表明它们的恒星形成更广泛,强度更低。星暴SMG的不规则紫外线形态可能反映了它们的合并性质。我们的研究结果表明,从高$z$ SMG的过渡到本地椭圆通过紧凑,静止星系(cQG)在$z \sim 2$可能不是普遍的,后者的人口也可能下降,从所谓的蓝块。

英文摘要:

We determine the physical properties of a sample of SMGs in the COSMOS field that were pre-selected at the observed wavelength of $λ_{\rm obs}=1.1$ mm, and followed up at $λ_{\rm obs}=1.3$ mm with ALMA. We used MAGPHYS to fit the panchromatic (ultraviolet to radio) SEDs of 124 of the target SMGs, 19.4% of which are spectroscopically confirmed. The SED analysis was complemented by estimating the gas masses of the SMGs by using the $λ_{\rm obs}=1.3$ mm emission as a tracer of the molecular gas. The sample median and 16th-84th percentile ranges of the stellar masses, SFRs, dust temperatures, and dust and gas masses were derived to be $\log(M_{\star}/{\rm M}_{\odot})=11.09^{+0.41}_{-0.53}$, ${\rm SFR}=402^{+661}_{-233}$ ${\rm M}_{\odot}~{\rm yr}^{-1}$, $T_{\rm dust}=39.7^{+9.7}_{-7.4}$ K, $\log(M_{\rm dust}/{\rm M}_{\odot})=9.01^{+0.20}_{-0.31}$, and $\log(M_{\rm gas}/{\rm M}_{\odot})=11.34^{+0.20}_{-0.23}$, respectively. The median gas-to-dust ratio and gas fraction were found to be $120^{+73}_{-30}$ and $0.62^{+0.27}_{-0.23}$, respectively. We found that 57.3% of our SMGs populate the main sequence (MS) of star-forming galaxies, while 41.9% of the sources lie above the MS by a factor of >3 (one source lies below the MS). The largest 3 GHz radio sizes are found among the MS sources. Those SMGs that appear irregular in the rest-frame UV are predominantly starbursts, while the MS SMGs are mostly disk-like. The larger radio-emitting sizes of the MS SMGs compared to starbursts is a likely indication of their more widespread, less intense star formation. The irregular UV morphologies of the starburst SMGs are likely to echo their merger nature. Our results suggest that the transition from high-$z$ SMGs to local ellipticals via compact, quiescent galaxies (cQGs) at $z \sim 2$ might not be universal, and the latter population might also descend from the so-called blue nuggets.

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