示河中心的伽射不太可能源自暗物＠PEREGRINE科滴

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示河中心的伽射不太可能源自暗物

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Bursts of gamma rays from the center of our galaxy are not likely to be signals of dark matter but rather other astrophysical phenomena such as fast-rotating stars called millisecond pulsars, according to two new studies, one from a team based at Princeton University and the Massachusetts Institute of Technology and another based in the Netherlands.

根一自，以美普林斯大及麻省理工院的，另一以荷之的新研究，源自河系中心的伽射爆，不太可能是暗物的信，而是如被毫秒星，快速旋之星的其他天物理象。

Previous studies suggested that gamma rays coming from the dense region of space in the inner Milky Way galaxy could be caused when invisible dark matter particles collide. But using new statistical analysis methods, the two research teams independently found that the gamma ray signals are uncharacteristic of those expected from dark matter. Both teams reported the finding today in the journal Physical Review Letters.

先前多研究暗示，自河系部空之稠密域的伽射，可能是不可之暗物粒子碰撞，致的。不，使用新的分析法，支研究分，伽射非典型之那些被期，自暗物的信。今天(2016年2月4日)，於《物理事》期刊，表了此。

1. 由美及荷支立行的的研究示，所到自星系部量之伽射，可能自新的源，而不是自暗物。最佳候者是快速旋的中子星，它是未搜的主要目。美普林斯大/麻省理工院的研究，及以荷基地的，使用了不同的技：非波松噪音(依循波松分的噪。波松分是一，表示生於固定或空隔之事件，倘若此些事件以已知的定平均速率，且打上次事件以上，之特定量事件可能性的散率分。)及非由於暗物湮(粒子反粒子相遇，互化射等其他能量形式)的射。

Studies by two independent groups from the U.S. and the Netherlands indicate that the observed excess of gamma rays from the inner galaxy likely comes from a new source rather than from dark matter. The best candidates are rapidly rotating neutron stars, which will be prime targets future searches. The Princeton University/Massachusetts Institute of Technology research group and the Netherlands-based group used two different techniques, non-Poissonian noise and ray signals were not due to dark matter annihilation.

“Our analysis suggests that what we are seeing is evidence for a new astrophysical source of gamma rays at the center of the galaxy,” said Mariangela Lisanti, an assistant professor of physics at Princeton. “This is a very complicated region of the sky and there are other astrophysical signals that could be confused with dark matter signals.”

普林斯大物理助理教授，Mariangela Lisanti宣：「我的分析暗示，所看到的是，伽射於河系中心之新天物理源的。是穹一很的域，因此有其他可能和暗物信混淆的天物理信。」

The center of the Milky Way galaxy is thought to contain dark matter because it is home to a dense concentration of mass, including dense clusters of stars and a black hole. A conclusive finding of dark matter collisions in the galactic center would be a major step forward in confirming our understanding of our universe.

河系中心被具有暗物，因它是稠密量集的所在地，包括密集的星及黑洞。在解咱宇宙上，河系中心暗物碰撞的性，是向前的重要一步。

“Finding direct evidence for these collisions would be interesting because it would help us understand the relationship between dark matter and ordinary matter,” said Benjamin Safdi, a postdoctoral researcher at MIT who earned his Ph.D. in 2014 at Princeton.

2014年於普林斯大得博士位，目前是麻省理工院博士後研究的Benjamin Safdi宣：「找到此些碰撞的直接，是引人感趣的。因，有助於我解，暗物普通物之的。」

To tell whether the signals were from dark matter versus other sources, the Princeton/MIT research team turned to image-processing techniques. They looked at what the gamma rays should look like if they indeed come from the collision of hypothesized dark matter particles known as weakly interacting massive particles, or WIMPs.

了言，此些是自暗物是其他源，普林斯大/麻省理工院的研究，向了影像理技。他探究了，倘若伽射自，被通弱交互作用之大量粒子(也就是WIMPs)的碰撞，它看起像什。

For the analysis, Lisanti, Safdi and Samuel Lee, a former postdoctoral research fellow at Princeton who is now at the Broad Institute, along with colleagues Wei Xue and Tracy Slatyer at MIT, studied images of gamma rays captured by NASA’s Fermi Gamma-ray Space Telescope, which has been mapping the rays since 2008.

了分析，Lisanti、Safdi及Samuel Lee(目前於麻省理工院暨哈佛大所布德研究所的普林斯大前博士後特研究)，同麻省理工院Wei Xue及Tracy Slatyer等，同僚研究了，由美航太署打2008年以，一直在此些射之米伽射太空望捕的伽射像。

Dark matter particles are thought to make up about 85 percent of the mass in the universe but have never been directly detected. The collision of two WIMPs, according to a widely accepted model of dark matter, causes them to annihilate each other to produce gamma rays, which are the highest-energy form of light in the universe.

暗物粒子被，成宇宙中大85%的量。不，未曾直接被探到。根泛被接受的暗物模型，WIMPs的碰撞，致它成互，生宇宙中，光最高能量形式的伽射。

According to this model, the high-energy particles of light, or photons, should be smoothly distributed among the pixels in the images captured by the Fermi telescope. In contrast, other sources, such as rotating stars known as pulsars, release bursts of light that show up as isolated, bright pixels.

根此模型，光的高能粒子(也就是光子)均分於，由米望捕之影像中的像素之。相之下，如被星之旋星的其他源，放出因孤立、明亮之像素，而得醒目的光爆。

The researchers applied their statistical analysis method to images collected by the Fermi telescope and found that the distribution of photons was clumpy rather than smooth, indicating that the gamma rays were unlikely to be caused by dark matter particle collisions.

此些研究人他的分析法，用於米望收集的像。了光子的分是，而不是均的。示，伽射不太可能，是由暗物粒子碰撞致的。

Exactly what these new sources are is unknown, Lisanti said, but one possibility is that they are very old, rapidly rotating stars known as millisecond pulsars. She said it would be possible to explore the source of the gamma rays using other types of sky surveys involving telescopes that detect radio frequencies.

Lisanti表示，此些新源究竟是什不。不，一可能性是，它是非常古老、被通毫秒星之快速旋的星。她表示，使用包括探率之望等，其他型的穹勘，探索伽射源，是可能的。

Douglas Finkbeiner, a professor of astronomy and physics at Harvard University who was not directly involved in the current study, said that although the finding complicates the search for dark matter, it leads to other areas of discovery.

未直接前研究之哈佛大的天文及物理教授，Douglas Finkbeiner表示，然了，暗物的搜。不，它引出多其他域的。

“Our job as astrophysicists is to characterize what we see in the universe, not get some predetermined, wished-for outcome. Of course it would be great to find dark matter, but just figuring out what is going on and making new discoveries is very exciting.”

他宣：「身天文物理家，我的工作是描述，在宇宙中所看到，得一些定、期望之果的特徵。然，找到暗物是很棒。不，弄清楚正在生的事，而做出新是非常令人振的。」

According to Christoph Weniger from the University of Amsterdam and lead author of the Netherlands-based study, the finding is a win-win situation: “Either we find hundreds of thousands of millisecond pulsars in the upcoming decade, shedding light on the history of the Milky Way, or we find nothing. In the latter case, a dark matter explanaton for the gamma ray excess will become much more obvious.”