Hello, my name is Karl Ziemelis, and I am the Chief Physical Sciences Editor for Nature.

　　大家好，我是Karl Ziemelis（卡爾 澤梅里斯），《自然》物理科學(xué)的總編。 

　　It is my pleasure today to introduce a new paper that we are publishing in Nature: the title is “Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources”.  

　　非常榮幸今天來(lái)為大家介紹即將發(fā)表在《自然》上的這篇論文：“Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources”。 

　　But first, let me give you a bit of background. 

　　首先我想向大家介紹一些研究背景。 

　　Cosmic rays are what we call the charged particles flying around the Universe at velocities approaching the speed of light. This is so fast that, for some of them, their energies can reach colossal values - more than 100 times greater than can be achieved for particles accelerated by researchers here on Earth – at the Large Hadron Collider, for example.  

　　宇宙射線是一些帶電粒子，在宇宙中以接近光速的速度飛行。它們的速度如此之快，以至于其中一些粒子所攜帶的能量十分巨大，例如，比地球上的科學(xué)家在大型強(qiáng)子對(duì)撞機(jī)上加速粒子所能達(dá)到的能量值還要高出100倍以上。 

　　We have a name for the powerful cosmic accelerators responsible for these extremely energetic cosmic rays – we call them PeVatrons. Where and what they are remains an open question, but this new paper provides some important clues. 

　　我們?yōu)檫@種驅(qū)動(dòng)宇宙粒子加速?gòu)亩蔀樘N(yùn)含極大能量宇宙射線的天體起了一個(gè)名字，拍電子伏特宇宙線加速器，即PeVatron。它們?cè)谀睦?，它們是什么，我們依舊沒(méi)有答案，但這篇論文為我們提供了一些重要的線索。 

　　Tracing the origin of these high-energy cosmic rays is not a straightforward task, as magnetic fields in space can cause their paths to twist and bend when they travel: so when we detect such a cosmic ray arriving at the earth, we may be able to determine the direction it arrived from, but this is not necessarily the same direction it started from. 

　　追蹤這些高能量宇宙射線并非易事，因?yàn)樘罩械拇艌?chǎng)會(huì)讓粒子的行進(jìn)路線扭曲、彎折，所以當(dāng)偵測(cè)到有這樣的射線抵達(dá)地球時(shí)，我們或許可以確定它到達(dá)的方向，但這個(gè)方向卻未必與其出發(fā)方向一致。 

　　But we do know that cosmic rays should produce γ-rays close to their accelerators, so maybe in searching instead for the sources of high-energy γ-rays could pinpoint the locations of these mysterious PeVatrons 

　　不過(guò)，我們已知宇宙射線在其加速器附近會(huì)產(chǎn)生γ射線，所以或許尋找這種高能γ射線可以為尋找這些神秘的PeVatron指明方向。 

　　This is what Zhen Cao and colleagues have done in the new paper. They report the detection of 12 sources of ultrahigh-energy γ-ray photons, each of which represents a potential PeVatron in the Milky Way galaxy. Although the precise location of most of these sources remains unclear, the authors do firmly identify one candidate in the well-known supernova remnant known as the Crab Nebula. 

　　這就是曹臻和同事們?cè)谶@個(gè)新研究中所做的工作。他們報(bào)告了檢測(cè)到的12個(gè)超高能γ射線光子源，其中的每一個(gè)都代表著銀河系中一個(gè)潛在的PeVatron。盡管這些光子源中大部分尚未找到準(zhǔn)確位置，但作者確認(rèn)了其中一個(gè)就位于著名的超新星遺跡蟹狀星云中。 

　　These exciting findings, while still preliminary, were made possible by observations from one of the arrays of the partially completed Large High-Altitude Air Shower Observatory in China. Many more of these sources are expected to be found once this instrument is complete.  

　　這些激動(dòng)人心的發(fā)現(xiàn)盡管還很初步，但卻是因?yàn)椴糠纸ǔ傻闹袊?guó)高海拔宇宙線觀測(cè)站的觀測(cè)工作才成為可能。未來(lái)待觀測(cè)站全部完工后，相信還會(huì)發(fā)現(xiàn)更多這樣的光子源。 

　　But what we can say for sure is that PeVatrons do exist in the Milky Way, and these findings bring us closer to understanding the origins of extremely high energy cosmic rays.  

　　不過(guò)我們已經(jīng)可以肯定銀河系中存在PeVatron，這些發(fā)現(xiàn)讓我們離了解高能宇宙射線起源又近了一步。 

　　Thank you 

　　謝謝大家！