哈勃望远镜观测繁忙的银河系中心
ESA/Hubble & NASA, M. Koss, A, Barth
This NASA/ESA Hubble Space Telescope image features the spiral galaxy IC 4709 located around 240 million light-years away in the southern constellation Telescopium. Hubble beautifully captures its faint halo and swirling disk filled with stars and dust bands. The compact region at its core might be the most remarkable sight. It holds an active galactic nucleus (AGN).
If IC 4709’s core just held stars, it wouldn’t be nearly as bright. Instead, it hosts a gargantuan black hole, 65 million times more massive than our Sun. A disk of gas spirals around and eventually into this black hole, crashing together and heating up as it spins. It reaches such high temperatures that it emits vast quantities of electromagnetic radiation, from infrared to visible to ultraviolet light and X-rays. A lane of dark dust, just visible at the center of the galaxy in the image above, obscures the AGN in IC 4709. The dust lane blocks any visible light emission from the nucleus itself. Hubble’s spectacular resolution, however, gives astronomers a detailed view of the interaction between the quite small AGN and its host galaxy. This is essential to understanding supermassive black holes in galaxies much more distant than IC 4709, where resolving such fine details is not possible.
This image incorporates data from two Hubble surveys of nearby AGNs originally identified by NASA’s Swift telescope. There are plans for Swift to collect new data on these galaxies. Swift houses three multiwavelength telescopes, collecting data in visible, ultraviolet, X-ray, and gamma-ray light. Its X-ray component will allow SWIFT to directly see the X-rays from IC 4709’s AGN breaking through the obscuring dust. ESA’s Euclid telescope — currently surveying the dark universe in optical and infrared light — will also image IC 4709 and other local AGNs. Their data, along with Hubble’s, provides astronomers with complementary views across the electromagnetic spectrum. Such views are key to fully research and better understand black holes and their influence on their host galaxies.
影像来源: ESA/Hubble & NASA, M. Koss, A, Barth
NASA/ESA哈勃太空望远镜的这张图片展示了位于南天星座望远镜座内、距离我们约2.4亿光年的螺旋星系IC 4709。哈勃精美地捕捉到了其微弱的光晕和充满恒星和尘埃带的旋转盘。其核心的紧凑区域可能是最引人注目的景象。它包含了一个活动星系核（AGN）。
如果IC 4709的核心只包含恒星，它的亮度不会如此显眼。相反，它拥有一个质量是我们太阳6500万倍的巨大黑洞。一个气体盘围绕并最终落入这个黑洞，在旋转过程中互相碰撞并加热。它达到了如此高的温度，以至于发出大量的电磁辐射，从红外光到可见光再到紫外光和X射线。在上图中，星系中心刚好能看到一条黑暗的尘埃带，这条尘埃带遮挡住了IC 4709中AGN的可见光辐射。然而，哈勃惊人的分辨率为天文学家提供了详细的视图，以便观察这个相当小的AGN与其宿主星系之间的相互作用。这对于理解比IC 4709更遥远的星系中的超大质量黑洞至关重要，因为在IC 4709中不可能分辨出如此精细的细节。
这张图片融合了哈勃对由NASA的SWIFT望远镜最初识别出的近距离AGN的两项调查的数据。SWIFT计划收集这些星系的新数据。SWIFT拥有三台多波长望远镜，收集可见光、紫外线、X射线和伽马射线数据。其X射线组件将使SWIFT能够直接看到IC 4709的AGN穿透遮挡尘埃发出的X射线。ESA的欧几里德望远镜目前正在用光学和红外光勘测暗宇宙，它也将对IC 4709和其他局部AGN进行成像。这些数据与哈勃的数据一起，为天文学家提供了整个电磁频谱的互补视角。这些视图对于全面研究和更好地理解黑洞及其对宿主星系的影响至关重要。