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首页> 外文期刊>Astronomy and astrophysics >Angular momentum evolution for galaxies in a Λ-CDM scenario
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Angular momentum evolution for galaxies in a Λ-CDM scenario

机译:Λ-CDM场景中星系的角动量演化

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摘要

Context. Galaxy formation in the current cosmological paradigm is a very complex process in which inflows, outflows, interactions, and mergers are common events. These processes can redistribute the angular momentum content of baryons. Recent observational results suggest that disc formed conserving angular momentum while elliptical galaxies, although they lose angular momentum, determine a correlation between the specific angular momentum of the galaxy and the stellar mass. These observations provide stringent constraints for galaxy formation models in a hierarchical clustering scenario. Aims. We aim to analyse the specific angular momentum content of the disc and bulge components as a function of virial mass, stellar mass, and redshift. We also estimate the size of the simulated galaxies and compare them with observations. Methods. We use cosmological hydrodynamical simulations that include an effective, physically motivated supernova feedback which is able to regulate the star formation in haloes of different masses. We analyse the morphology and formation history of a sample of galaxies in a cosmological simulation by performing a bulge-disc decomposition of the analysed systems and their progenitors. We estimate the angular momentum content of the stellar and gaseous discs, stellar bulges, and total baryons. Results. In agreement with recent observational findings, our simulated galaxies have disc and spheroid components whose specific angular momentum content determine correlations with the stellar and dark matter masses with the same slope, although the spheroidal components are offset by a fixed fraction. The average angular momentum efficiency for the simulated discs is η ~ 1, while for bulges it is η ~ 0.10?0.20. For the simulated sample, the correlations found for the specific angular momentum content as a function of virial mass or stellar mass are found not to evolve significantly with redshift (up to z ~ 2). Both dynamical components seem to move along the correlations as they evolve. The total specific angular momentum of galaxies occupy different positions filling the gap between pure rotational-dominated and dispersion-dominated systems. The scaling relations derived from the simulated galaxies determine a similar relation with the virial radius, which is in agreement with recent observations.
机译:上下文。当前宇宙学范式中的星系形成是一个非常复杂的过程,其中流入,流出,相互作用和合并是常见事件。这些过程可以重新分配重子的角动量含量。最近的观测结果表明,圆盘形成了守恒的角动量,而椭圆形星系尽管失去了角动量,却决定了星系的特定角动量与恒星质量之间的相关性。这些观察为分层聚类场景中的星系形成模型提供了严格的约束。目的我们旨在分析视盘和凸出部分的特定角动量含量,作为病毒质量,恒星质量和红移的函数。我们还估计了模拟星系的大小,并将其与观测值进行比较。方法。我们使用宇宙流体力学模拟,包括有效的,物理动机的超新星反馈,该反馈能够调节不同质量晕圈中恒星的形成。通过对被分析系统及其祖先进行凸圆盘分解,我们在宇宙学模拟中分析了星系样本的形态和形成历史。我们估计了恒星和气碟,恒星凸起和总重子的角动量含量。结果。与最近的观测结果一致,我们的模拟星系具有圆盘和球状体分量,尽管球状体分量被固定分数抵消,但它们的特定角动量含量决定了与具有相同斜率的恒星和暗物质质量之间的相关性。模拟圆盘的平均角动量效率为η〜1,而凸起时为η〜0.10-0.20。对于模拟样品,发现特定角动量含量随病毒质量或恒星质量而变化的相关性不会随红移显着变化(最大z〜2)。两个动力学成分似乎随着它们的发展而沿相关性移动。星系的总比角动量占据了不同位置,填补了纯旋转为主和色散为主系统之间的空白。从模拟星系得出的比例关系确定了与病毒半径的相似关系,这与最近的观察一致。

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