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Photons with a trillion times more energy than visible light are flying out of a relatively nearby galaxy.
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光子从相对较近的星系中飞速流出，携带的能量比可见光高出一万亿倍。
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Until now, scientists didn't understand this light's origin, but a new study shows that its source is a giant black hole inside the M87 galaxy. The radiation takes the form of high-frequency gamma rays.
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此前，科学家们不清楚这种光子的来源。然而，一项新研究表明，其源泉是星系M87内部一个巨大的黑洞。这种辐射是以高频伽马射线的形式出现的。
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"We detect it in roughly 25 galaxies so far but we never knew where exactly it was coming from," said study team member Matthias Beilicke, an astrophysicist at Washington University in St. Louis. "Only in the case of M87 were we able to narrow it down to the black hole vicinity."
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“到目前为止，我们大致在25个星系中发现了这样的射线，但我们以前从未搞清这种射线到底来自何处，”研究小组成员、华盛顿大学圣路易斯分校的天体物理学家马赛厄斯·比利克说，“只有在M87的情况中，我们可以将射线源的范围缩小到黑洞附近。”
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Matter funnels into the supermassive black hole from a ring of material circling around it and called an accretion disk. Some matter is also propelled out in very bright jets that stream across space.
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在黑洞周围旋转的物质环带叫做吸积盘，其中的物质沿着漏斗状的通道进入这个超大质量的黑洞中。一些物质也被喷出来，形成极其明亮的射流，横穿太空。
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One hypothesis suggests the gamma-ray flares occur when an extra amount of matter is pulled out of the accretion disk and injected into the jets. Either electrons or protons in the jet could interact with light photons or matter to create the extremely high-energy gamma rays.
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一个假设提出：当吸积盘中排出过多的物质，并且加入射流的时候，伽马射线闪光就产生了。在射流中，不管是电子还是质子都可以跟可见光子或者物质相互作用，产生极高能量的伽马射线。
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"This acceleration mechanism requires strong magnetic fields which can be found around the black hole," Beilicke said. "We need charged particles accelerated to very high energies in order to emit gamma rays at these energies."
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“这种加速机制需要存在于黑洞周围的强磁场，”比利克说，“要想使释放的伽马射线达到如此高的能量，我们需要将带电粒子加速到极高的能量。”
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The observations could help scientists understand the environment around gigantic black holes like this one, which contains the mass of more than six billion suns.
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这些观测可能有助于科学家们理解巨型黑洞的周围环境，象这个黑洞就相当于60多亿颗太阳的质量。
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"The fact that there are particles accelerated up to such high speeds gives us input for the modeling of these systems," Beilicke told SPACE.com. "M87 is so far more or less the only source which really allows this particular kind of study."
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“速度增加到如此之高的粒子是存在的，这个事实为我们提供了模拟这些系统所需的输入资料，”比利克告诉太空网的记者说，“到目前为止，从某种程度上说，星系M87是唯一一个真正可以进行此类研究的目标源。”
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The researchers were able to pin down the radiation's origination point by combining measurements of the gamma-rays with radio-wave observations. Even though gamma rays cannot usually pierce through Earth's atmosphere, ground-based telescopes can detect them by looking for telltale flashes of faint blue light that result when gamma rays hit the air. These observations also reflect the direction the gamma rays came from, though they are not very precise.
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研究人员把对伽马射线的观测和对无线电波的观测结合起来，可以确定这种辐射的发源点。即使伽马射线通常不能穿透地球的大气，但是由于伽马射线撞击大气时会产生暗蓝色的闪光，地面望远镜通过寻找这样的闪光仍然可以发现伽马射线。尽管这些观测资料不太准确，但还是可以反映出伽马射线的来源方向。
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Astronomers also observed M87 with the National Science Foundation's Very Long Baseline Array (VLBA), a group of radio telescopes spread out around the United States. These observations revealed a burst of radio light that coincided with the gamma-ray flares, which usually lasted a few days.
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天文学家们还利用国家科学基金会的特长基线望远镜阵列（VLBA）观测了星系M87。特长基线望远镜阵列是遍布全美的一组射电望远镜。这些观测显示，射电光的爆发跟伽马射线的闪光是同步的，通常会持续几天。
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The radio flares, imaged with much more precision than gamma-ray light, could be traced back to the location of the supermassive black hole in the center of M87.
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射电光的成像比伽马射线光要准确得多，可以直接跟踪返回到M87中心黑洞的位置。
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"Combining the gamma-ray observations with the supersharp radio 'vision' of the VLBA allowed us to see that the gamma rays are coming from a region very near the black hole itself," said team member Craig Walker of the National Radio Astronomy Observatory (NRAO).
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“结合对伽马射线的观测和特长基线望远镜阵列拍下的超清晰射电图像，使我们明白伽马射线来自非常接近黑洞本身的一个区域，”研究小组成员、国家射电天文台（NRAO）的克雷格·沃克说。
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M87, at 50 million light-years from Earth, is much closer than any similar gamma-ray flare sources, so it could be scientists’ best bet to study these systems for a while.
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M87距地球5000万光年，比任何类似的伽马射线光源都要近得多，所以该星系是科学家们目前研究这些系统的首选目标。
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The new study is detailed in the July 2 issue of the journal Science.
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这项新研究详细地记录在7月2日出版的《科学》杂志上。
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