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arXiv 1809.10752astro-ph.GA
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VALES V:用ALMA对$z\sim0.03-0.35$的ATLAS星系中分子气体含量的运动学分析

VALES V: A kinematic analysis of the molecular gas content in $H$-ATLAS galaxies at $z\sim0.03-0.35$ using ALMA

J. Molina, Edo Ibar, V. Villanueva, A. Escala, C. Cheng, M. Baes, H. Messias, C. Yang, F. E. Bauer, P. van der Werf, R. Leiton, M. Aravena, A. M. Swinbank, M. J… 展开作者

J. Molina, Edo Ibar, V. Villanueva, A. Escala, C. Cheng, M. Baes, H. Messias, C. Yang, F. E. Bauer, P. van der Werf, R. Leiton, M. Aravena, A. M. Swinbank, M. J. Michałowski, A. M. Muñoz-Arancibia, G. Orellana, T. M. Hughes, D. Farrah, G. De Zotti, M. A. Lara-López, S. Eales, L. Dunne

摘要:

我们提出了阿塔卡玛大型毫米/亚毫米阵列(ALMA)解决的星系分子气体的观测$z=0.35$全球星系动力学对全球星际介质(ISM)的性质的作用。这些观测包括从瓦尔帕莱索ALMA线发射巡天(VALES)中获取的39个星系的子样本。从CO($J=1-0)$)发射线,我们量化的运动学参数通过模拟的速度场。我们发现,红外光度增加的旋转色散速度比($V_{\rm rot}/σ_v$,倾斜校正)。我们发现$V_{\rm rot}/σ_v$和[CII]/IR比值之间存在依赖关系,这表明所谓的“[CII]赤字”与星系的动力学状态有关。我们发现,全球压力的支持,需要调和的动力学质量估计与恒星质量在我们的系统低$V_{\rm rot}/σ_v$值。在我们的样本中,恒星形成率(SFR)与分子气体分数($f_{\rm H_2}$)弱相关,这表明冷气体的引力能释放可能不是VALES星系湍流运动的主要能量来源。通过定义一个代理的“恒星形成效率”参数为SFR除以CO光度(SFE $'\equiv$ SFR/L $'_{\rm CO}$),我们发现一个恒定的SFE $'$每穿越时间($t_{\rm cross}$)。我们认为$t_{\rm cross}$可能是尘埃$z\sim0.03-0.35$星系中恒星形成的控制时间尺度。

英文摘要:

We present Atacama Large Millimeter/submillimeter Array (ALMA) resolved observations of molecular gas in galaxies up to $z=0.35$ to characterise the role of global galactic dynamics on the global interstellar medium (ISM) properties. These observations consist of a sub-sample of 39 galaxies taken from the Valparaíso ALMA Line Emission Survey (VALES). From the CO($J=1-0)$ emission line, we quantify the kinematic parameters by modelling the velocity fields. We find that the IR luminosity increases with the rotational to dispersion velocity ratio ($V_{\rm rot}/σ_v$, corrected for inclination). We find a dependence between $V_{\rm rot}/σ_v$ and the [CII]/IR ratio, suggesting that the so-called `[CII] deficit' is related to the dynamical state of the galaxies. We find that global pressure support is needed to reconcile the dynamical mass estimates with the stellar masses in our systems with low $V_{\rm rot}/σ_v$ values. The star formation rate (SFR) is weakly correlated with the molecular gas fraction ($f_{\rm H_2}$) in our sample, suggesting that the release of gravitational energy from cold gas may not be the main energy source of the turbulent motions seen in the VALES galaxies. By defining a proxy of the `star formation efficiency' parameter as the SFR divided by the CO luminosity (SFE$'\equiv$ SFR/L$'_{\rm CO}$), we find a constant SFE$'$ per crossing time ($t_{\rm cross}$). We suggest that $t_{\rm cross}$ may be the controlling timescale in which the star formation occurs in dusty $z\sim0.03-0.35$ galaxies.

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