Formation and Evolution of Barred Galaxies

棒星系的形成和演化

• 批准号: 298620-2013
• 负责人: Martel, Hugo
• 金额: $ 1.82万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=594920
• 关键词: Formation; Evolution; Barred; Galaxies

A large fraction of spiral galaxies contain bars. The presence of a bar can greatly affect the evolution of the host galaxy. The bar channels gas into the center of galaxies, where it is converted into stars. The nuclear reactions in these stars produce heavy elements (called "metals"), that are then ejected into the gas when the stars explode in supernovae. Also, if there is a supermassive black hole in the center of the galaxy, the gas flowing along the bar might fall onto the black hole, producing an active galactic nuclei (or AGN). We would therefore expect barred galaxies to have higher central star formation rates (SFR), higher central metallicity, and more intense AGN activity than unbarred galaxies. However, recent observations reveal a more complex picture. Only galaxies with strong bars show enhanced central star formation, and not all of them do: There appears to be significant differences between massive barred galaxies (stellar masses larger than 10-30 billion solar masses) and low-mass ones. All barred galaxies show an enhancement in central metallicity, but low-mass barred galaxies do not show a corresponding enhancement in central star formation. Some high-mass barred galaxies do, but not all of them. Instead, some massive galaxies with strong bars show a suppression of central star formation. This suggests that bars might, under some circumstances, quench star formation in the central regions, instead of boosting it. Also, we observe an anti-correlation between star formation and AGN activity in the center of barred galaxies. These observations reveal that galaxies of different masses, or with bars of different strength, can have drastically different star formation histories. To fully understand the evolution of these galaxies, we need to understand the interplay between the various physical processes driving this evolution. We propose to pursue a long-term project to study the evolution of barred galaxies. We will perform a series of numerical simulations of galaxy evolution. Our goal is to understand the physical processes that determine the history of star formation and metallicity in barred galaxies, and determine the role played by feedback in quenching star formation in some barred galaxies.

大部分的螺旋星系包含条。棒的存在会极大地影响宿主星系的演变。条将气体通道进入星系中心，并将其转换为恒星。这些恒星中的核反应产生了沉重的元素（称为“金属”），然后在恒星在超新星中爆炸时将其弹出到气体中。同样，如果银河系中心有一个超质量的黑洞，则沿着杆的气体可能落到黑洞上，产生一个活跃的银河核（或AGN）。因此，与未挂钩星系相比，我们预计禁止星系具有更高的中央恒星形成率（SFR），更高的中央金属性和更强烈的AGN活性。但是，最近的观察结果显示出更为复杂的情况。只有杆强的星系显示出增强的中央恒星形成，而不是所有的星系：大量禁止的星系（大于100亿太阳能量）和低质量的星系之间似乎存在显着差异。所有禁止的星系均显示中央金属性的增强，但是低质量的星系并未显示中央恒星形成中相应的增强。一些高质量禁止的星系可以做到，但并非全部。取而代之的是，一些具有较强条形的大型星系显示出对中央恒星形成的抑制。这表明，在某些情况下，酒吧可能会在中央地区淬灭星星的形成，而不是促进它。同样，我们观察到禁止星系中心的恒星形成与AGN活性之间的抗相关性。这些观察结果表明，不同质量的星系或具有不同强度的条的星系可能具有截然不同的恒星形成历史。为了充分理解这些星系的演变，我们需要了解推动这种演变的各种物理过程之间的相互作用。我们建议从事一个长期项目，以研究禁止星系的演变。我们将对星系演化进行一系列数值模拟。我们的目标是了解确定禁止星系中恒星形成和金属性历史的物理过程，并确定反馈在某些禁止的星系中反馈在淬火星形成中所起的作用。