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arXiv 1806.07752astro-ph.GA
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Galerkin到$z\sim 3$的晕质量:观测和理论的混合方法

The Halo Masses of Galaxies to $z\sim 3$: A Hybrid Observational and Theoretical Approach

Christopher J. Conselice, Jonathan W. Twite, David P. Palamara, William Hartley

摘要:

我们使用混合观测/理论的方法来研究星系运动学和派生的恒星和星系晕质量z=3作为恒星质量,红移和形态的函数之间的关系。我们的观测样本由1125个星系的串联组成,这些星系在长缝和积分场研究中具有0.4<z<3的运动学测量。我们调查了几种方法来测量晕质量的观测结果的基础上,从半分析模型,表明星系晕质量可以检索的分散度为0.4德克斯只使用恒星质量。我们发现了第三个参数,有关的时间形成的晕,这减少了恒星和晕质量之间的关系的分散,这样的系统形成较早有较高的恒星质量晕质量比,我们也发现观测。我们发现这种散射与形态学有关,例如早期类型或较老的恒星系统具有较高的M_*/M_halo比。我们进一步使用这种方法,并通过弱透镜和丰度匹配,恒星与晕质量的比率在1<z<3时不会随红移显着变化。这是证据,为规范的星系分级大会,使恒星的比例,暗物质的质量保持近似恒定,因为$z = 2$。我们利用这些结果表明,暗物质吸积速率的演变从$dM_{\rm halo}/d{\rm t} \sim 4000$ M太阳年$^{-1}$在$z \sim 2.5$,到几个100 M太阳年$^{-1}$由$z \sim 0.5$。

英文摘要:

We use a hybrid observational/theoretical approach to study the relation between galaxy kinematics and the derived stellar and halo masses of galaxies up to z=3 as a function of stellar mass, redshift and morphology. Our observational sample consists of a concatenation of 1125 galaxies with kinematic measurements at 0.4<z<3 from long-slit and integral-field studies. We investigate several ways to measure halo masses from observations based on results from semi-analytical models, showing that galaxy halo masses can be retrieved with a scatter of ~0.4 dex by using only stellar masses. We discover a third parameter, relating to the time of the formation of the halo, which reduces the scatter in the relation between the stellar and halo masses, such that systems forming earlier have a higher stellar mass to halo mass ratio, which we also find observationally. We find that this scatter correlates with morphology, such that early-type, or older stellar systems, have higher M_*/M_halo ratios. We furthermore show using this approach, and through weak lensing and abundance matching, that the ratio of stellar to halo mass does not significantly evolve with redshift at 1<z<3. This is evidence for the regulated hierarchical assembly of galaxies such that the ratio of stellar to dark matter mass remains approximately constant since $z = 2$. We use these results to show that the dark matter accretion rate evolves from $dM_{\rm halo}/d{\rm t} \sim 4000$ M_solar year$^{-1}$ at $z \sim 2.5$, to a few 100 M_solar year$^{-1}$ by $z \sim 0.5$.

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