半人马座A：特殊的星系

2023年5月3日

Centaurus A: A Peculiar Island of Stars
Image Credit & Copyright: Marco Lorenzi, Angus Lau & Tommy Tse; Text: Natalia Lewandowska (SUNY Oswego)

Explanation: Galaxies are fascinating. In galaxies, gravity alone holds together massive collections of stars, dust, interstellar gas, stellar remnants and dark matter. Pictured is NGC 5128, better known as Centaurus A. Cen A is the fifth brightest galaxy on the sky and is located at a distance of about 12 million light years from Earth. The warped shape of Cen A is the result of a merger between an elliptical and a spiral galaxy. Its active galactic nucleus harbors a supermassive black hole that is about 55 million times more massive than our Sun. This central black hole ejects a fast jet visible in both radio and X-ray light. Filaments of the jet are visible in red in the upper left. New observations by the Event Horizon Telescope have revealed a brightening of the jet only towards its edges — but for reasons that are currently unknown and an active topic of research.

At NASA it’s: Black Hole Week

Tomorrow’s picture: black hole revisited

半人马座A：特殊的星系
影像提供与版权: Marco Lorenzi, Angus Lau & Tommy Tse; 文稿: Natalia Lewandowska (SUNY Oswego)

说明: 星系是很迷人的天体。星系光靠重力，就能将大量的恒星、尘埃、星际气体、恒星残骸、和暗物质聚集在一起。这幅影像所呈现的是距离约1200万光年远，天空中第五亮的星系；其编录号为NGC 5128，不过更常见的称号是半人马A（Centaurus A）。半人马A的扭曲外观，咸认是椭圆星系和螺旋星系合并后的产物。半人马A拥有活跃的星系核，其中心有质量是太阳5500万倍的超大质量黑洞。这个中心黑洞射出的高速喷流，在无线电及X射线波段皆可见。而在影像左上角，还可见到位在喷流指向的泛红丝状物。事件视界望远镜的新观测显示，这道喷流边缘在增亮，然而其成因不明，目前为活跃的研究课题。

在NASA这是: 黑洞周

明日的图片: black hole revisited