arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.00004astro-ph.GAastro-ph.CO
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IllustrisTNG模拟中的淬灭分数:与观测和其它理论模型的比较

Quenched fractions in the IllustrisTNG simulations: comparison with observations and other theoretical models

Martina Donnari, Annalisa Pillepich, Dylan Nelson, Federico Marinacci, Mark Vogelsberger, Lars Hernquist

摘要:

我们做了深入的比较的IllustrisTNG模拟与观测数据的淬火分数的中央和卫星星系,$M_*=10^{9-12}M_{\odot}$在$0\leq z\leq3$。我们研究了分析方法和观察效应如何影响这种比较。这包括测量选择-孔径,淬火定义,恒星形成率(SFR)指标时标-以及观测的不确定性和样本选择问题:投影效应,卫星/中心误分类,和主机质量分布抽样。用来区分淬灭星系和恒星形成星系的定义产生了高达70(30)$\%$的中心(卫星)$>\sim 10^{10.5} M_{\odot}$的差异。增加测量SFR的孔径可以将淬灭分数抑制高达$\sim50\%$,特别是在$z\gtrsim2$下。适当考虑恒星和主机的质量分布是至关重要的:天真的体积有限的模拟样品的比较导致误解的淬火分数作为$z$的函数高达20 $\%$。包括观测不确定性的理论值的$M_*$和SFR的变化淬火分数值和它们的趋势和/或斜率与质量。采用卫星的投影距离而不是3D距离,由于场污染,使淬灭分数减少多达10 $\%$。与数据比较,TNG产生的淬灭馏分与观测结果基本一致。TNG预测淬灭分数高达$\sim80-90\%$的中心在$z\leq2-3$,符合最近的观察,并显着高于其他理论模型。TNG和SDSS的卫星淬灭分数在集团和集群的定量协议强烈依赖于星系和主机的质量范围。我们在TNG和SDSS之间的模拟比较突出了正确解释观测效应和偏差的重要性。

英文摘要:

We make an in-depth comparison of the IllustrisTNG simulations with observational data on the quenched fractions of central and satellite galaxies, for $M_*=10^{9-12}M_{\odot}$ at $0\leq z\leq3$. We study how analysis methodologies and observational effects impact this comparison. This includes measurement choices -- aperture, quenched definition, star formation rate (SFR) indicator timescale -- as well as observational uncertainties and sample selection issues: projection effects, satellite/central misclassification, and host mass distribution sampling. The definition used to separate quenched and star-forming galaxies produces differences of up to 70 (30)$\%$ for centrals (satellites) $>\sim 10^{10.5} M_{\odot}$. Increasing the aperture within which SFR is measured can suppress the quenched fractions by up to $\sim50\%$, particularly at $z\gtrsim2$. Proper consideration of the stellar and host mass distributions is crucial: naive comparisons to volume-limited samples from simulations lead to misinterpretation of the quenched fractions as a function of $z$ by up to 20$\%$. Including observational uncertainties to theoretical values of $M_*$ and SFR changes the quenched fraction values and their trend and/or slope with mass. Taking projected rather than 3D distances for satellites decreases the quenched fractions by up to 10$\%$ due to field contamination. Comparing with data, TNG produces quenched fractions broadly consistent with observations. TNG predicts quenched fractions up to $\sim80-90\%$ for centrals at $z\leq2-3$, in line with recent observations, and notably higher than other theoretical models. The quantitative agreement of TNG and SDSS for satellite quenched fractions in groups and clusters depends strongly on the galaxy and host mass range. Our mock comparison between TNG and SDSS highlights the importance of properly accounting for observational effects and biases.

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