Using NASA’s Chandra X-ray Observatory, scientists have discovered a new class of objects behaving unlike any they have seen before. Astronomers suggest these newly spotted objects in other galaxies may help solve not one, but two long-standing questions in astrophysics.
利用美国宇航局的钱德拉 X 射线天文台，科学家们发现了一类新的物体，它们的行为与他们以前见过的任何物体都不同。天文学家认为，其他星系中新发现的这些天体可能有助于解决天体物理学中长期存在的两个问题，而不是一个问题。
These mysterious objects give off unusually low-energy X-rays but intense levels of ultraviolet radiation. This discovery is featured in a paper published Wednesday in Nature Astronomy.
这些神秘物体发出异常低能量的 X 射线，但发出强烈的紫外线辐射。这一发现发表在周三《自然天文学》杂志上的一篇论文中。
“We’ve never encountered a group of objects that act like this,” said Mustafa Muhibullah of the University of Alabama who led the study. “Of course, the next step was to try to figure out what these things are.”
领导这项研究的阿拉巴马大学穆斯塔法·穆希布拉 (Mustafa Muhibullah) 表示：“我们从未遇到过具有这样行为的物体群。” “当然，下一步是尝试弄清楚这些东西是什么。”
The researchers found a total of 84 of these “hypersoft X-ray sources” – so named because they give such low-energy X-rays – in the six different galaxies they searched, using data openly available to the public in the Chandra archive. Two of the galaxies are spirals, M31 (the Andromeda galaxy) and M101 (the Pinwheel galaxy), while the other four are ellipticals. They found hypersoft X-ray sources both in regions of active star formation and areas where there are older stars.
研究人员使用钱德拉档案中向公众公开的数据，在他们搜索的六个不同星系中总共发现了 84 个此类“超软 X 射线源”（如此命名是因为它们发出如此低能量的 X 射线）。其中两个星系是螺旋星系，M31（仙女座星系）和 M101（风车星系），而其他四个星系是椭圆星系。他们在活跃恒星形成区域和老年恒星区域都发现了超软X射线源。
The team spotted the sources by finding objects that appeared in Chandra images taken at the lowest X-ray energies but vanished in higher-energy images. That means these objects give off far more low-energy X-rays than high-energy ones. Because low-energy X-rays border energetic ultraviolet radiation on the electromagnetic spectrum, the researchers determined that these sources are producing large amounts of energetic ultraviolet radiation as well.
研究小组通过寻找在最低 X 射线能量拍摄的钱德拉图像中出现但在较高能量图像中消失的物体来发现来源。这意味着这些物体发出的低能 X 射线远多于高能 X 射线。由于低能 X 射线与电磁波谱上的高能紫外线辐射相邻，研究人员确定这些源也会产生大量高能紫外线辐射。
It is unclear what types of objects are responsible for these low-energy X-rays and intense ultraviolet radiation. The team thinks they most likely involve a black hole, neutron star, or white dwarf pulling material from a companion star. The material pulled from the companion star is heated up to produce X-rays before falling onto the white dwarf or neutron star, or into the black hole. Such binary systems have been seen before, but not with such bright ultraviolet radiation and low-energy X-rays.
目前尚不清楚是什么类型的物体产生了这些低能 X 射线和强烈的紫外线辐射。研究小组认为它们很可能涉及黑洞、中子星或白矮星从伴星中拉出物质。从伴星中拉出的物质被加热以产生 X 射线，然后落到白矮星或中子星上，或者落入黑洞中。这种双星系统以前曾被发现过，但从未见过如此明亮的紫外线辐射和低能 X 射线。
The discovery suggests that there may be large populations of binary systems with energetic ultraviolet radiation that have been undetected until now.
这一发现表明，可能存在大量具有高能紫外线辐射的双星系统，但迄今为止尚未被发现。
“These clandestine X-ray sources are actually among the most energetic objects in galaxies, and they could be solving two cosmic mysteries at once,” said Muhibullah.
穆希布拉说：“这些秘密 X 射线源实际上是星系中能量最高的物体之一，它们可以同时解决两个宇宙之谜。”
Scientists think that some white dwarf systems pulling material from companion stars may eventually explode as a supernova – known as a Type Ia – that is critical for measuring the expansion of the universe. These supernovae played a key role in discovering that this expansion is accelerating. Astronomers have been looking for the stars that turn into Type Ia supernovae for many years, so far without success.
科学家认为，一些白矮星系统从伴星中提取物质最终可能会爆炸为超新星（称为 Ia 型），这对于测量宇宙的膨胀至关重要。这些超新星在发现这种膨胀正在加速的过程中发挥了关键作用。多年来，天文学家一直在寻找会变成 Ia 型超新星的恒星，但迄今为止尚未成功。
“If we could find a way to spot these Type Ia supernova explosions before they go off, that would be really important,” said co-author Jimmy Irwin, also of the University of Alabama. “Right now, we study them after they’ve exploded, and astronomers have struggled to understand what is actually ignited.”
“如果我们能找到一种方法在这些 Ia 型超新星爆炸爆发之前发现它们，那将非常重要，”共同作者、阿拉巴马大学的吉米·欧文 (Jimmy Irwin) 说。 “现在，我们在它们爆炸后对其进行研究，天文学家一直在努力了解到底是什么被点燃了。”
The other mystery these hypersoft X-ray sources might explain is what strips electrons from gas between the stars in some galaxies. This stripping of electrons is important to probe because it can affect how quickly stars form and influence the life cycles of galaxies. Hot, massive stars play a role, but they do not completely explain what is causing this stripping. The intense levels of ultraviolet radiation from the hypersoft X-ray sources may play a vital role.
这些超软X射线源可能解释的另一个谜团是，是什么从某些星系中恒星之间的气体中剥离电子。这种电子剥离对于探测很重要，因为它会影响恒星形成的速度并影响星系的生命周期。炽热的大质量恒星发挥了一定作用，但它们并不能完全解释导致这种剥离的原因。超软 X 射线源发出的强烈紫外线辐射可能发挥着至关重要的作用。
Why were these hypersoft X-ray sources not found until now? In addition to the low-energy X-ray output, which is very difficult for X-ray telescopes to detect, the high-energy ultraviolet radiation is readily absorbed by helium and hydrogen gas that fills the space between the stars, creating a nearly impenetrable barrier to look through.
为什么直到现在才发现这些超软X射线源？除了 X 射线望远镜很难探测到的低能 X 射线输出外，高能紫外线辐射很容易被填充在恒星之间空间的氦气和氢气吸收，形成一个几乎无法穿透的屏障。
“By combing through the Chandra archive, we were able to eliminate what used to be a blind spot for telescopes,” said co-author Rosanne Di Stefano of the Center for Astrophysics | Harvard & Smithsonian. “That’s how we found what appears to be a new class of cosmic objects with remarkable qualities.”
天体物理中心的合著者 Rosanne Di Stefano 表示：“通过梳理钱德拉档案，我们能够消除曾经是望远镜的盲点。”哈佛和史密森尼。 “这就是我们如何发现一类具有非凡品质的新型宇宙物体的方式。”
NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
美国宇航局位于阿拉巴马州亨茨维尔的马歇尔太空飞行中心负责管理钱德拉计划。史密森天体物理观测站的钱德拉 X 射线中心控制着马萨诸塞州剑桥的科学业务和马萨诸塞州伯灵顿的飞行业务。
To learn more about NASA’s Chandra mission, visit:
要了解有关 NASA 钱德拉任务的更多信息，请访问：
This release features a composite image of a spiral galaxy, M101; one of six identified galaxies housing a new class of mysterious objects that give off unusually low-energy X-rays.
此版本包含螺旋星系 M101 的合成图像；六个已确定的星系之一，其中蕴藏着一类新型神秘天体，这些天体会发出异常低能的 X 射线。
In this composite image, M101 faces us directly. It has multiple arms in shades of purple, spiraling clockwise around a golden yellow core. Scattered along and between the arms are scores of tiny specks in white and purple. Most of those specks are pairs of stars, but seven of them are a mystery.
在这张合成图像中，M101 正对着我们。它有多个紫色的臂，围绕金黄色的核心顺时针旋转。手臂上和手臂之间散布着许多白色和紫色的小斑点。这些斑点大多数是成对的恒星，但其中有七颗是个谜。
To casual observers, the unusual objects are visually indistinguishable from the other specks of light in the galaxy. An annotated version of the composite image is included in this release, with red circles around the mysterious specks for easy identification.
对于不经意的观察者来说，这些不寻常的物体在视觉上与银河系中的其他光点无法区分。此版本中包含合成图像的带注释版本，神秘斑点周围有红色圆圈，以便于识别。
These mystery specks behave like no other class of object discovered before. The curious objects give off X-rays of such low energy, they in fact produce large amounts of ultraviolet radiation, as UV radiation borders X-rays on the electromagnetic spectrum. Searching images of galaxies with low-energy X-rays in the Chandra Observatory archive, scientists have found a total of 84 such objects spread across M101 and five other galaxies. They have dubbed these mysterious objects “hypersoft X-ray sources.”
这些神秘斑点的行为与之前发现的其他物体不同。这些奇怪的物体发出如此低能量的 X 射线，它们实际上会产生大量的紫外线辐射，因为紫外线辐射与电磁频谱上的 X 射线接壤。科学家们在钱德拉天文台档案中搜索低能 X 射线星系图像，发现总共 84 个此类物体分布在 M101 和其他五个星系中。他们将这些神秘物体称为“超软X射线源”。