半人马座A：特殊的星系

半人马座A：特殊的星系

ByNASA中文

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…

星系NGC 1947的线状物

星系NGC 1947的线状物

ByNASA中文

2021年04月07日 Threads of NGC 1947 Image Credit: ESA/Hubble & NASA, D. Rosario; Acknowledgment: L. Shatz Explanation: Found in far southern skies, deep within the boundaries of the constellation Dorado, NGC 1947 is some 40 million light-years away. In silhouette against starlight, obscuring lanes of cosmic dust thread across the peculiar galaxy’s bright central regions. Unlike the rotation of stars, gas, and dust tracing the arms of spiral galaxies, the motions of dust and gas don’t follow the motions of stars in NGC 1947 though. Their more complicated disconnected motion suggest this galaxy’s visible threads of dust and gas may have come from a donor galaxy, accreted by NGC 1947 during the last 3 billion years or so of the peculiar galaxy’s evolution. With spiky foreground…