星系

Cepheid variable stars – a class of stars named in honor of Delta Cephei – serve as cosmic yardsticks, enabling astronomers to measure the distances to faraway galaxies.

造父变星——是一类根据仙王座δ起名的星星——被作为宇宙尺子，使天文学家能够用它们来测量到遥远星系的距离。

Cepheid variable stars – a class of stars named in honor of Delta Cephei – serve as cosmic yardsticks, enabling astronomers to measure the distances to faraway galaxies.

造父变星——为了纪念仙王座δ而命名的恒星——作为天文学家们测量遥远星系的距离的宇宙尺度。

In this paper, we argue that the new Cerenkov line-like radiation mechanism suggested by You et al. can provide a solution for the puzzle of EW(subscript Kα)/EW(subscript Kβ). We present a detailed model consideration and theoretical calculation.

给出了详细的模型考虑和理论计算，结果表明活动星系核中产生铁K线的机制不只有莹光机制还有Cerenkov线状辐射机制。

Our calculated result shows that, except for the fluorescence emission, there coexists a Cerenkov line-like radiation mechanism in AGNs, which gives a significant contribution to the iron K-line emission, even moderately higher than the former.

两者共存于活动星系核中，而且以Cerenkov辐射机制为主。

The Cherenkov telescopes do not actually detect the gamma rays directly but instead detect the flashes of visible light produced when gamma rays are absorbed by the Earth's atmosphere.

只有10 ％的伽玛射线源的非瞬态来源。这些稳定的伽玛射线发射器包括脉冲星，中子星和黑洞的候选人，如活动星系核。

It is also another name for the constellation called "The Northern Cross."

它也是南十字星系的另一个名称。

Explanation: NGC 1132 is one smooth galaxy -- but how did it form?

说明： NGC1132是一个圆滑的星系—但它是怎么形成的呢？

This is a Hubble Space Telescope galaxy NGC 1097 around the core of the star forming regions.

这是哈勃太空望远镜拍摄的环绕NGC 1097星系核心的恒星形成区。

NGC 1275 is one of the closest giant elliptical galaxies.

NGC1275 是最近的巨椭圆星系之一。

One of these galaxies was NGC 4258, whose distance was very accurately determined through observations with radio telescopes.

其中的一个星系是NGC 4258，它的距离已经由射电望远镜阵列非常精确的测量过。

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。