Using the detailed eyes of the Atacama Large Millimeter/submillimeter Array (ALMA) and ESO’s Very Large Telescope (VLT), astronomers have mapped the intense tails of a cosmic jellyfish: a number of knotty streams of gas spewing outwards from a spiral galaxy named ESO 137-001. This celestial cnidarian is shown here in beautiful detail. The various elements making up this image were captured by different telescopes. The galaxy and its surroundings were imaged by the NASA/ESA Hubble Space Telescope; its tails, which trace streams of hydrogen and show up in hues of bright purple, by the MUSE instrument mounted on the VLT; and bright hotspots of carbon dioxide emission from within the system, which show up as flares of orange-red, were spotted by ALMA. These tails are caused by a dramatic phenomenon known as ram-pressure stripping. The space between galaxies in a cluster is not empty, but full of material that acts like a viscous fluid. As a galaxy travels through this resistant environment, gas is stripped out of the galaxy to form a wake that creates beautiful, intricate systems such as that seen here around ESO 137-001 (which resides in the Norma galaxy cluster). The direction and position of the tail shed light on the way in which the galaxy is moving — with galaxies usually falling towards the centre of the cluster itself. This image offers the first high-resolution map of the cold molecular gas lurking within a ram-pressure stripped system. ESO 137-001 is one of the nearest jellyfish galaxies to Earth, and is particularly interesting because its long, extended tails of gas contain features known as ‘fireballs’: bursts of star formation. The precise mechanisms governing how stars form within jellyfish tails are mysterious, and this map thus provides a new window onto the conditions needed for new stars to form in such intense, changeable environments.  The ALMA array comprises 66 antennas, and is located on the Chajinator plateau in the Chilean Atacama Dese


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凹瑪望遠鏡觀測到的水母星系,正式名稱為ESO 137-001。南半球有個「矩尺座」,水母星系是「矩尺座星系團」的一部分,距離地球約2億2000萬光年。矩尺座星系團裏有好幾百個星系。其中之一的這個水母星系ESO 137-001,以時速700萬公里朝向銀河的中心移動。由於這種快速的運動,所以氣體被從該星系向外推出,長出一條25萬光年長的尾巴。


用凹瑪望遠鏡觀測了在水母星系ESO 137-001裡面的一氧化碳的,是捷克科學研究院的天文學家Pavel Jáchym和他的9位團隊伙伴,包括美國、加拿大、英國、澳大利亞、葡萄牙、法國等天文學家。這項研究發表在天文學專業雜誌《天文物理期刊》上。

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