Life Is Too Fast, Too Furious for Runaway Galaxy
The spiral galaxy ESO 137-001 looks like a dandelion caught in a breeze in
this new composite image from the Chandra X-ray Observatory and the Hubble Space Telescope.
The galaxy is
zooming toward the upper left 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
detected by Chandra (blue).
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 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.
NASA
Guillermo Gonzalo Sánchez Achutegui
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