Life is Too Fast, Too Furious for This Runaway Galaxy
The spiral galaxy ESO 137-001 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
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
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
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
Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Acknowledgment: M. Sun (University of Alabama, Huntsville)