jianjie

中国天文学会学术期刊

天文学进展

PROGRESS IN ASTRONOMY

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盘状星系形成中的角动量问题

罗智坚^1,2，傅莉萍³，束成钢^1,3
(1. 中国科学院上海天文台，上海 200030；2. 江西师范大学物理系，南昌 330027；
3. 上海师范大学天体物理中心，上海 200234)

摘要

目前的星系形成理论认为，盘状星系由暗晕中的重子物质冷却并坍缩而成。在这一演化图像中，重子物质的角动量及其分布起着关键作用，它直接决定了盘状星系的结构。然而，在盘状星系形成和演化的各种解析、半解析模型及数值模拟中，出现了一系列与角动量有关的问题。其中包括角动量灾变（angular momentum catastrophe）及角动量分布不匹配（mismatch of angular- momentum profile）等。近年来，为解决此类问题，人们进行了大量的研究，引入并建立了各种机制和模型。详细表述了星系形成与演化中两类主要的角动量问题，并系统地综述了目前针对此类问题所提出的各种可能的解决方法和途径。

The Angular Momentum Problems in Disk Galaxy Formation

LUO Zhi-jian^1,2, FU Li-ping³, SHU Cheng-gang^1,3(1. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China;
2. Physics Department, Jiangxi Normal University, Nanchang 330027, China;
3. Shanghai United Center for Astrophysics, Shanghai Normal University, Shanghai 200234, China)

　Abstract

In the current paradigm of galaxy formation, disk galaxies are assumed to form by the cooling and condensation of baryons within dark matter halos. In this scenario, the angular momentum of baryons and its distribution play key roles, which govern the structures of disk galaxies. However, some difficulties about angular momentum emerged for both analytic or/and semi-analytic models and numerical simulation of disk galaxy formation. The main problems include the angular momentum catastrophe, mismatch of angular-momentum profiles and so on. A number of mechanisms and various models have been proposed in order to resolve these problems. In the present paper, we describe in detail two main categories of angular momentum problems in disk galaxy formation, and summarize the methods which could solve these problems.