Computational Planet, Star and Galaxy Formation

计算天体物理学使天文学家能够看到恒星和星系在他们眼前重现并演化的梦想。年轻恒星周围的圆盘中可以有大量的气体。通过计算机模拟，我们最近证明了在理想条件下，这些圆盘自发破碎，形成了比木星更大的巨大气体行星。成对的年轻恒星几乎会相撞，并将星盘撕裂成一串棕矮星。但这些星盘和年轻行星物体通过红外辐射失去热量的速度很慢，因此它们应该被膨胀，这是我们现在打算在模型中包括的特性。我们还将为整个年轻星团建模，以获得更真实和更猛烈的行星形成环境！--最近模拟的一个重大成功是在计算机上形成了令人信服的螺旋星系。*模拟的星系形成了数十亿年。在被认为相当安静的演化过程中消耗气体和较小的星系。因此，它们包含了薄薄的恒星圆盘，这些恒星以与银河系中真实的恒星数量一致的方式在宇宙中形成。戏剧性的合并事件可以将这些安静的星系转变为宇宙中可见的各种星系类型，并将其中的一些气体和恒星驱动成其中心的贪婪的黑洞。为了更好地模拟这些星系，我们正在为气体和它如何冷却黑洞、恒星如何形成以及恒星如何在高能超新星爆炸中死亡等问题制定更详细的处方。

Computational astrophysics enables the astronomer's dream of seeing stars and galaxies come to life and evolve before their eyes.  Young stars can have substantial amounts of gas in disks around them.  With computer simulations we have recently demonstrated that these disks spontaneously fragment under ideal conditions to create giant gas planets larger than Jupiter. Pairs of young stars can nearly collide and shred the disks into a string of brown dwarfs.  These disks and young planetary objects are slow to lose their heat through infrared radiation and so they should be puffed up, a property we now intend to include in our models.  We will also model entire clusters of young stars for a much more realistic and violent planet forming environment!     A major success of recent simulations is the formation of convincing spiral galaxies on a computer.  The simulated galaxies form over billions of years, consuming gas and smaller galaxies in what is regarded as fairly quiet evolution.  As a result they contain thin disks of stars that formed over the age of the universe in a manner consistent with real stellar populations in the Milky Way.  Dramatic merger events can transform these quiet galaxies into the full range of galaxies types seen in the universe and also drive some of their gas and stars into voracious black holes at their centres.  To model these galaxies even better we are developing even more detailed prescriptions for the gas and how it cools, black holes, how stars form and how stars die in energetic supernova explosions.