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| The spiral galaxy NGC 4258, located 20 million light-years from Earth. NASA/ESA/LEGUS |
NASA’s Hubble Space Telescope has been used to snap some ultraviolet images of nearby galaxies – and they’re rather awesome, to say the least. The galaxies were imaged as part of a project called Legacy ExtraGalactic UV Survey (LEGUS). Astronomers used new and old Hubble observations to study 50 spiral and dwarf galaxies in our local universe, ranging from 11 to 58 million light-years from us.
The goal of this particular project was to
observe star formation in these galaxies, and locate clusters of stars. This
has enabled the researchers to draw up catalogs of the stars and clusters in 30
of the galaxies.
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| This is the dwarf galaxy UGC 5340, which is 40 million light-years away. NASA/ESA/LEGUS |
"There has never before been a
star cluster and a stellar catalog that included observations in ultraviolet
light," survey leader Daniela Calzetti from the University of
Massachusetts, Amherst, said in a statement. "Ultraviolet light is a major
tracer of the youngest and hottest star populations, which astronomers need to
derive the ages of stars and get a complete stellar history. The synergy of the
two catalogs combined offers an unprecedented potential for understanding star
formation."
The star clusters they observed in
the galaxies have ages from 1 million to 500 million years, giving them a broad
spectrum of stellar history. In total, this catalog contains a whopping 8,000
star clusters, and 39 million hot blue stars – ones that are at least five
times the mass of our Sun.
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| Here we've got the dwarf galaxy UGCA, 18 million light-years away. NASA/ESA/LEGUS |
From the survey, astronomers hope to
try and work out what role star formation plays in shaping a galaxy, such as
the spiral arms of galaxies like our own. This will give a better picture of
how different stars end up in different places in a given galaxy, with most
tending to follow an ordered structure. And they want to learn more about star
formation itself.
"Much of the light we get from
the universe comes from stars, and yet we still don't understand many aspects
of how stars form," team member Elena Sabbi of the Space Telescope Science
Institute in Baltimore, Maryland, said in the statement.
"This is even key to our
existence – we know life wouldn't be here if we didn’t have a star
around."
Below are some of the more amazing
images from this survey, looking at spiral arms, dwarf galaxies, and more. The
brighter and bluer regions in each galaxy tend to be the areas of greater star
formation, so see if you can pick a few of them out.
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| This spiral galaxy, 35 million light-years away, is called NGC 3368. NASA/ESA/LEGUS |
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| This is the spiral galaxy NGC 3627, which is 36 million light-years away. NASA/ESA/LEGUS |
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