NASA News: Nasa's Hubble Observes Young Dwarf Galaxies Bursting With Stars

WASHINGTON -- Using its near-infrared vision to peer 9 billion years
back in time, NASA's Hubble Space Telescope has uncovered an
extraordinary population of young dwarf galaxies brimming with star
formation. While dwarf galaxies are the most common type of galaxy in
the universe, the rapid star-birth observed in these newly found
examples may force astronomers to reassess their understanding of the
ways in which galaxies form.

The galaxies are a hundred times less massive, on average, than the
Milky Way, yet churn out stars at such a furious pace that their
stellar content would double in just 10 million years. By comparison,
the Milky Way would take a thousand times longer to double its star population.

The universe is estimated to be 13.7 billion years old, and these
newly discovered galaxies are extreme even for the young universe --
when most galaxies were forming stars at higher rates than they are
today. Astronomers using Hubble's instruments could spot the galaxies
because the radiation from young, hot stars has caused the oxygen in
the gas surrounding them to light up like a bright neon sign.

"The galaxies have been there all along, but up until recently
astronomers have been able only to survey tiny patches of sky at the
sensitivities necessary to detect them," said Arjen van der Wel of
the Max Planck Institute for Astronomy in Heidelberg, Germany, lead
author of a paper on the results being published online on Nov. 14 in
The Astrophysical Journal. "We weren't looking specifically for these
galaxies, but they stood out because of their unusual colors."

The observations were part of the Cosmic Assembly Near-infrared Deep
Extragalactic Legacy Survey (CANDELS), an ambitious three-year study
to analyze the most distant galaxies in the universe. CANDELS is the
first census of dwarf galaxies at such an early epoch
.
"In addition to the images, Hubble has captured spectra that show us
the oxygen in a handful of galaxies and confirmed their extreme
star-forming nature," said co-author Amber Straughn at NASA's Goddard
Space Flight Center in Greenbelt, Md. "Spectra are like fingerprints.
They tell us the galaxies' chemical composition."

The resulting observations are somewhat at odds with recent detailed
studies of the dwarf galaxies that are orbiting as satellites of the
Milky Way.

"Those studies suggest that star formation was a relatively slow
process, stretching out over billions of years," explained Harry
Ferguson of the Space Telescope Science Institute (STScI) in
Baltimore, Md., co-leader of the CANDELS survey. "The CANDELS finding
that there were galaxies of roughly the same size forming stars at
very rapid rates at early times is forcing us to re-examine what we
thought we knew about dwarf galaxy evolution."

The CANDELS team uncovered the 69 young dwarf galaxies in
near-infrared images taken with Hubble's Wide Field Camera 3 and
Advanced Camera for Surveys.

The observations suggest that the newly discovered galaxies were very
common 9 billion years ago. However, it is a mystery why the newly
found dwarf galaxies were making batches of stars at such a high
rate. Computer simulations show star formation in small galaxies may
be episodic. Gas cools and collapses to form stars. The stars then
reheat the gas and blow it away, as in supernova explosions. After
some time, the gas cools and collapses again, producing a new burst
of star formation, continuing the cycle.

"While these theoretical predictions may provide hints to explain the
star formation in these newly discovered galaxies, the observed
bursts are much more intense than what the simulations can
reproduce," van der Wel said.

The James Webb Space Telescope, an infrared observatory scheduled to
launch later this decade, will be able to probe these faint galaxies
at an even earlier era to see the glow of their stars, reveal their
chemical composition, and offer better details on their formation.

The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency. Goddard manages the
telescope. STScI conducts Hubble science operations and is operated
for NASA by the Association of Universities for Research in Astronomy
Inc. in Washington.

For images and more information about Hubble and the CANDELS results, visit:

http://www.nasa.gov/hubble

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NASA's New Upper Stage Engine Passes Major Test

BAY ST. LOUIS, Miss. -- NASA conducted a successful 500-second test
firing of the J-2X rocket engine on Wednesday, Nov. 9, marking
another important step in development of an upper stage for the
heavy-lift Space Launch System (SLS).

SLS will carry the Orion spacecraft, its crew, cargo, equipment and
science experiments to destinations in deep space. SLS will be safe,
affordable and sustainable to continue America's journey of discovery
from the unique vantage point of space.

"The J-2X engine is critical to the development of the Space Launch
System," Dan Dumbacher, NASA's deputy associate administrator for
exploration systems development, said after the test at NASA's
Stennis Space Center in Mississippi. "Today's test means NASA is
moving closer to developing the rocket it needs if humans are to
explore beyond low-Earth orbit."

Data from the test will be analyzed as operators prepare for
additional engine firings. The J-2X and the RS-25D/E engines for the
SLS core stage will be tested for flight certification at Stennis.
Both engines use liquid hydrogen and liquid oxygen propellants. The
core stage engines were developed originally for the space shuttle.

"The J-2X engine team and the SLS program as a whole are extremely
happy that we accomplished a good, safe and successful test today,"
said Mike Kynard, Space Launch System Engines Element Manager at
NASA's Marshall Space Flight Center in Huntsville, Ala. "This engine
test firing gives us critical data to move forward in the engine's development."

Stennis has tested engines that carried Americans to space in both the
Apollo and Space Shuttle programs. The J-2X engine is being developed
for Marshall by Pratt & Whitney Rocketdyne of Canoga Park, Calif.

"We look forward to adding to the legacy as we fulfill our
responsibility to test engines that will power America's next launch
vehicle," said Stennis Director Patrick Scheuermann.

For more information about NASA exploration, visit:

http://www.nasa.gov/exploration

For information about NASA's Space Launch System, visit:

http://www.nasa.gov/SLS

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NASA Space Station Crewmen Available For In-Flight Interviews

HOUSTON -- Two NASA astronauts soon will be aboard the International
Space Station and available for regularly scheduled interview
opportunities with accredited news media.

Daniel Burbank, a veteran of two space shuttle missions to assemble
the station, will launch with Russian crewmates on a Soyuz spacecraft
from Kazakhstan on Sunday, Nov. 13. Arriving at the complex on Nov.
16 for a four-month mission, Burbank will command the Expedition 30
crew through mid-March.

Donald Pettit will join Burbank in late December when he launches from
Kazakhstan with Russian and European crewmates in another Soyuz
spacecraft. Pettit will remain on the station for five months,
returning to Earth in mid-May after serving as part of the Expedition
30 and 31 crews. He is a veteran of a long-duration mission on the
station as part of the Expedition 6 crew in 2002 and 2003, as well as
a subsequent space shuttle mission to assemble the station.

Because of the nature of human spaceflight activities, news media must
remain flexible to accommodate scheduling changes in interview times
and dates. These opportunities are scheduled in the crew members'
timeline each week, generally in the morning between 8 a.m. and noon CST.

In-flight interviews are broadcast on NASA Television and streamed on
the agency's website. News media must have two dedicated telephone
lines available and be able to receive NASA TV via NASA's LIMO
Channel to communicate with and view the astronauts.

The channel is a digital satellite C-band downlink provided by
Americom. It is on satellite SES-2, transponder 9C, located at 87
degrees west, downlink frequency 3865.5 MHz based on a standard
C-band, horizontal downlink polarity. FEC is 3/4, data rate is 6.0
Mbps, symbol rate is 4.3404 Msps, transmission DVB-S, 4:2:0.

News media must email a detailed interview proposal to Rob Navias at
rob.navias-1@nasa.gov or Kylie Clem at kylie.s.clem@nasa.gov.
For NASA TV streaming video, downlink and scheduling information, visit:

http://www.nasa.gov/ntv

For biographical information and other astronaut information, visit:

http://www.nasa.gov/astronauts

For more information about the International Space Station, visit:

http://www.nasa.gov/station

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