星系

Most galaxies abound with interstellar gas and dust, the detritus of countless generations of stars.

绝大多数星系有着丰富的星际气体和尘埃，这些都是无数代恒星散落下来的物质材料。

We present semi-analytic models and Monte-Carlo simulations of QSO Lyman α absorption line systems...

本文结合星系形成理论，研究了低红移的类星体吸收线系统的起源与性质。

Keywords: quasar absorption line systems; semi-analytical models; galaxy formation; simulations

中文关键词：类星体吸收线系统；半解析模型；星系形成；数值模拟

The thorium abundance ratio measured for the star in the Ursa Minor dwarf galaxy is as low as that found in the oldest stars in the Milky Way, suggesting that this star could be at least 12 billion years old.

钍丰度比测得的星在URSA患者小矮星系是低至那被发现在古老的恒星在银河系中，暗示这颗恒星可能至少有12亿年之久。

Some, such as those around which galaxies are believed to accrete, formed just after the beginning of the universe.

一些黑洞，比如说其周围的星系在增长的黑洞，恰好形成于宇宙刚产生之后。

These results are consistent with the scenario of small black hole and high accretion rate for NLS1s.

这些结果与窄线SeyfertⅠ型星系的小黑洞高吸积率模型一致。

But the question is, does this happen to every single jet or active nucleus, or are we seeing some odd behavior from M87?

但问题是，这仅仅是M87过去的行为还是它将会发生在每个活动星系核或者单个喷流中？

Active Galactic Nucleus have been an important branch and one of the most active frontiers in the field of modern astrophysics. It is related to the most fundamental problems in astrophysics .

活动星系核是现代天体物理学研究的重大前沿课题，涉及到天体物理学中最基本的问题。

But, unlike the black hole at the centre of our Milky Way, the million-solar-mass black hole inside NGC 4945 is an Active Galactic Nucleus that is frantically consuming any surrounding matter, and so releasing tremendous amounts of energy.

但与银河系核心的黑洞不同，NGC 4945中数百万太阳质量的超级黑洞正在疯狂地吞噬周围的物质、并释放极为巨大的能量——是个活跃星系核。

Blasting out from the active galactic nucleus toward the upper left, the energetic jet extends about 13,000 light-years.

高能喷流从活动星系核喷向影像左上方，一直延长大约有1.3万光年远。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。