Gravitational lens helps reveal "fireworks" in the early universe
Without the magnification boost of the gravitational lens, Johnson added, the disk galaxy would appear perfectly smooth and unremarkable to Hubble. This would give astronomers a very different picture of where stars are forming.
When
it comes to the distant universe, even the keen vision of NASA’s Hubble
Space Telescope can only go so far. Teasing out finer details requires
clever thinking and a little help from a cosmic alignment with a
gravitational lens.
By applying a new computational analysis to a galaxy magnified by a
gravitational lens, astronomers have obtained images 10 times sharper
than what Hubble could achieve on its own. The results show an edge-on
disk galaxy studded with brilliant patches of newly formed stars.
“When we saw the reconstructed image we said, ‘Wow, it looks like
fireworks are going off everywhere,’” said astronomer Jane Rigby of
NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
The galaxy in question is so far away that we see it as it appeared
11 billion years ago, only 2.7 billion years after the big bang. It is
one of more than 70 strongly lensed galaxies studied by the Hubble Space
Telescope, following up targets selected by the Sloan Giant Arcs
Survey, which discovered hundreds of strongly lensed galaxies by
searching Sloan Digital Sky Survey imaging data covering one-fourth of
the sky.
The gravity of a giant cluster of galaxies between the target galaxy
and Earth distorts the more distant galaxy’s light, stretching it into
an arc and also magnifying it almost 30 times. The team had to develop
special computer code to remove the distortions caused by the
gravitational lens, and reveal the disk galaxy as it would normally
appear.
The resulting reconstructed image revealed two dozen clumps of
newborn stars, each spanning about 200 to 300 light-years. This
contradicted theories suggesting that star-forming regions in the
distant, early universe were much larger, 3,000 light-years or more in
size.
“There are star-forming knots as far down in size as we can see,”
said doctoral student Traci Johnson of the University of Michigan, lead
author of two of the three papers describing the research.
Without the magnification boost of the gravitational lens, Johnson added, the disk galaxy would appear perfectly smooth and unremarkable to Hubble. This would give astronomers a very different picture of where stars are forming.
While Hubble highlighted new stars within the lensed galaxy, NASA’s
James Webb Space Telescope will uncover older, redder stars that formed
even earlier in the galaxy’s history. It will also peer through any
obscuring dust within the galaxy.
“With the Webb Telescope, we’ll be able to tell you what happened in
this galaxy in the past, and what we missed with Hubble because of
dust,” said Rigby.
These findings appear in a paper published in The Astrophysical Journal Letters, and two additional papers published in The Astrophysical Journal and The Astrophysical Journal.
The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency. NASA’s Goddard Space Flight
Center in Greenbelt, Maryland, manages the telescope. The Space
Telescope Science Institute (STScI) in Baltimore, Maryland, conducts
Hubble science operations. STScI is operated for NASA by the Association
of Universities for Research in Astronomy in Washington, D.C.
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Contacts
Christine Pulliam / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4366 / 410-338-4514
cpulliam@stsci.edu / villard@stsci.edu
Dr. Jane Rigby
NASA's Goddard Space Flight Center, Greenbelt, Maryland
301-286-1507 (office) / 240-475-3917 (cell)
jane.r.rigby@nasa.gov
Traci Johnson
University of Michigan, Ann Arbor, Michigan
612-325-1402
tljohn@umich.edu
Space Telescope Science Institute, Baltimore, Maryland
410-338-4366 / 410-338-4514
cpulliam@stsci.edu / villard@stsci.edu
Dr. Jane Rigby
NASA's Goddard Space Flight Center, Greenbelt, Maryland
301-286-1507 (office) / 240-475-3917 (cell)
jane.r.rigby@nasa.gov
Traci Johnson
University of Michigan, Ann Arbor, Michigan
612-325-1402
tljohn@umich.edu
Source: HubbleSite
