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发表于 2010-7-21 11:02:49
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Astronomers Solve The Mystery of Hanny's Voorwerp
天文学家们解决Voorwerp之谜
Astrophysicists finally discover the origin of a supergiant cloud of green-glowing gas that is floating in intergalactic space.
天体物理学家最终发现漂浮在星际空间的巨型绿色发光气体云的来源。
In 2007, a Dutch school teacher called Hanny van Arkel discovered an extraordinary object while combing though images for the Galaxy Zoo project to classify galaxies. The object appears as a bright green blob close to a spiral galaxy in the constellation of Leo Minor and soon became known as Hanny's Voorwerp (meaning Hanny's object in Dutch).
2007年，一个名叫Hanny van Arkel的荷兰教师在为银河动物园项目分类星系时于图像中发现了一个特殊的对象，该对象显示为一个靠近小狮座螺旋星系的绿色小斑点，很快这个对象被称为Hanny的Voorwerp（意思是在荷兰的Hanny的对象）
Hanny's Voorwerp is astounding because astronomers have never seen anything like it. Although galactic in scale, it is clearly not a galaxy because it does not contain any stars. Detailed spectrographic observations since its discovery suggest that it is a giant cloud of gas that is glowing an unusual green colour.
Hanny的Voorwerp是令人惊奇的，因为天文学家们从未见过类似这样的东西。虽然它具备类似星系的规模，但并不是星系，因为它不包括任何星体。详细的光谱观测表明，它是一团发出不寻常的绿光的巨型气体云。
That raises an obvious question: what is causing the gas to glow?
这带来了一个问题： 什么导致这些气体发光？
Today, Hayden Rampadarath at the Joint Institute for VLBI in Europe, based in the the Netherlands and a multitude of friends, provide an answer. Their data comes from a new study of the nearby spiral galaxy IC 2497 using a couple of very long baseline interferometers to study the region at various wavelengths.
今天，欧洲VLBI网联合研究所（这个不知道怎么翻，不过貌似是一个机构http://www.jive.nl）的Hayden Rampadarath（可能是人名？），在荷兰以及其他朋友的研究基础上，提出了一个假设。他们的数据来自于使用几个超长基线干涉仪对螺旋星系IC 2497附近各种波长区域的一项新的研究。
Their conclusion is that, like many galaxies, IC 2497 contains a massive black hole at its centre. The infall of matter into the black hole generates a cone of radiation emitted in a specific direction. The great cloud of gas that is Hanny's Voorwerp just happens to be in the firing line. The black hole radiation is ionising the gas, causing it to glow green.
他们的结论是，像许多星系一样，IC 2497的中心有一个巨大的黑洞。物质流入黑洞的过程会产生对特定方向的锥形辐射。Hanny的Voorwerp的巨型气体云正好位于射线的路径上，黑洞的辐射电离其中的气体，产生了绿光。
What has confused the issue is that another cloud of dust and gas sits between us on Earth and IC 2497 and this prevents us from directly seeing the black hole (or the active galactic nucleus as astronomers call it).
位于地球和IC 2497之间的另一个尘埃和气体云阻止我们直接观察到黑洞（天文学家也称之为活动星系核），这对结论会产生一些影响。
That seems a sensible interpretation. And certainly more likely than another idea put forward last year. This proposed that some 10,000 years ago, IC 2497 suddenly underwent a dramatic outburst of quasar-like radiation and then became quiet. What we see today from this cloud of gas some 10,000 light years from IC 2497, is simply a reflection of this outburst. In other words, Hanny's Voorwerp is a quasar light echo.
这似乎是合理的解释，比去年提出的另一种想法更有可能。这个猜测是，约10000年前，IC 2497经历了突然的类星体辐射剧烈爆发然后变得寂静。我们现在看到从10000光年外的IC 2497的气体云发出的光，只是当时爆发的一个反射，换而言之，Voorwerp是一个星体光回波。
That was unsatisfactory because it resolved one mystery merely by posing another: what could cause an entire galaxy to flare up briefly and suddenly?
这个假设并不令人满意，因为它只是由一个问题转化为另一个问题：是什么会导致整个星系短暂和突然的爆发？
The evidence that IC 2497 is still active today puts to rest this idea. It also explains why Voorwerps are so rare: the radiation cones from active galactic nuclei are highly directional so only occasionally do unlucky gas clouds get caught in the cross fire.
IC 2497今天仍处于活动状态的证据支持了这一假设。它还解释了为什么Voorwerps如此罕见：从活动星系核发射的辐射锥具备高方向性，气体云只是偶然会位于其路径上。 |
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发表于 2010-7-17 15:24:51