Our spiral-shaped Milky Way galaxy lives in a comparatively quiet backwater region of the universe. This is not the case for galaxies crammed together inside huge clusters. As they zip around within a cluster, gas can be pulled from their disks due to a process called ram pressure stripping. Galaxy ESO 137-001 is one example. The star-city looks like it is “leaking” as it plunges through the Norma galaxy cluster.
The spiral galaxy looks like a dandelion caught in a breeze in this new Hubble Space Telescope image.
The galaxy is zooming toward the upper right of this image, in between other galaxies in the Norma cluster located over 200 million light-years away. The road is harsh: intergalactic gas in the Norma cluster is sparse, but so hot at 180 million degrees Fahrenheit that it glows in X-rays.
The spiral plows through the seething intra-cluster gas so rapidly — at nearly 4.5 million miles per hour — much of its own gas is caught and torn away. Astronomers call this “ram pressure stripping.” The galaxy’s stars remain intact due to the binding force of their gravity.
Tattered threads of gas, the blue jellyfish-tendrils sported by ESO 137-001 in the image, illustrate the process. Ram pressure has strung this gas away from its home in the spiral galaxy and out over intergalactic space. Once there, these strips of gas have erupted with young, massive stars, which are pumping out light in vivid blues and ultraviolet.
The brown, smoky region near the center of the spiral is being pushed in a similar manner, although in this case it is small dust particles, and not gas, that are being dragged backwards by the intra-cluster medium.
From a star-forming perspective, ESO 137-001 really is spreading its seeds into space like a dandelion in the wind. The stripped gas is now forming stars. However, the galaxy, drained of its own star-forming fuel, will have trouble making stars in the future. Through studying this runaway spiral, and other galaxies like it, astronomers hope to gain a better understanding of how galaxies form stars and evolve over time.
The image, obtained through Hubble’s Wide Field Camera 3, is also decorated with hundreds of stars from within the Milky Way. Though not connected in the slightest to ESO 137-001, these stars and the two reddish elliptical galaxies contribute to a vibrant celestial vista.
Zoom into ESO 137-001: This video zooms in on spiral galaxy ESO 137-001, which is undergoing ram pressure stripping. The sequence begins with a view of the night sky near the constellation of Triangulum Australe (the Southern Triangle). It then zooms through observations from the Digitized Sky Survey 2, and ends with a view of the galaxy obtained by Hubble. Credit: NASA, ESA, M. Kornmesser (HEIC), and G. Bacon (STScI)
Animation of Ram Pressure Stripping: his artist’s illustration shows a spiral galaxy as it moves through a massive cluster of galaxies. The galaxy is undergoing a process known as ram pressure stripping, where streaks of bright gas are being dragged out into space by the cluster it is passing through. Credit: NASA, ESA, and M. Kornmesser (HEIC)
Top image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Have something to add to this story? Share it in the comments.
Filed under: Deep Space
