Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov
IMAGE ADVISORY: 2008-061 April 16, 2008
A new image from NASA's Galaxy Evolution Explorer shows baby stars sprouting
in the backwoods of a galaxy -- a relatively desolate region of space more
than 100,000 light-years from the galaxy's bustling center.
The striking image, a composite of ultraviolet data from the Galaxy Evolution
Explorer and radio data from the National Science Foundation's Very Large Array
in New Mexico, shows the Southern Pinwheel galaxy, also known simply as M83.
In the new view, the main spiral, or stellar, disk of M83 looks like a pink and
blue pinwheel, while its outer arms appear to flap away from the galaxy like giant
red streamers. It is within these so-called extended galaxy arms that, to the
surprise of astronomers, new stars are forming.
"It is absolutely stunning that we find such an enormous number of young stars up
to 140,000 light-years away from the center of M83," said Frank Bigiel of the Max
Planck Institute for Astronomy in Germany, lead investigator of the new Galaxy
Evolution Explorer observations. For comparison, the diameter of M83 is only
40,000 light-years across.
The new image is online at www.nasa.gov/mission_pag...0080416.html .
Some of the "outback" stars in M83's extended arms were first spotted by the Galaxy
Evolution Explorer in 2005. Remote stars were also discovered around other galaxies
by the ultraviolet telescope over subsequent years. This came as a surprise to
astronomers because the outlying regions of a galaxy are assumed to be relatively
barren and lack high concentrations of the ingredients needed for stars to form.
The newest Galaxy Evolution Explorer observations of M83 (colored blue and green)
were taken over a longer period of time and reveal many more young clusters of stars
at the farthest reaches of the galaxy. To better understand how stars could form in
such unexpected territory, Bigiel and his colleagues turned to radio observations
from the Very Large Array (red). Light emitted in the radio portion of the electromagnetic
spectrum can be used to locate gaseous hydrogen atoms, or raw ingredients of stars. When
the astronomers combined the radio and Galaxy Evolution Explorer data, they were
delighted to see they matched up.
"The degree to which the ultraviolet emission and therefore the distribution of young
stars follows the distribution of the atomic hydrogen gas out to the largest distances
is absolutely remarkable," said Fabian Walter, also of the Max Planck Institute for Astronomy,
who led the radio observations of hydrogen in the galaxy.
The astronomers speculate that the young stars seen far out in M83 could have formed under
conditions resembling those of the early universe, a time when space was not yet enriched
with dust and heavier elements.
"Even with today's most powerful telescopes, it is extremely difficult to study the first
generation of star formation. These new observations provide a unique opportunity to
study how early generation stars might have formed," said co-investigator Mark Seibert
of the Observatories of the Carnegie Institution of Washington in Pasadena.
M83 is located 15 million light-years away in the southern constellation Hydra.
Other investigators include: Barry Madore of The Observatories of the Carnegie Institution
of Washington; Armando Gil de Paz of the Complutense University of Madrid, Spain; David
Thilker of Johns Hopkins University, Baltimore; Elias Brinks of the University of
Hertfordshire, England; and Erwin de Blok of the University of Cape Town, South Africa.
The California Institute of Technology in Pasadena leads the Galaxy Evolution Explorer
mission and is responsible for science operations and data analysis. NASA's Jet Propulsion
Laboratory, also in Pasadena, manages the mission and built the science instrument.
Caltech manages JPL for NASA. The mission was developed under NASA's Explorers Program
managed by NASA's Goddard Space Flight Center, Greenbelt, Md. Researchers sponsored by
Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in
France collaborated on this mission.
The Very Large Array is part of the National Radio Astronomy Observatory, a facility
of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
Additional information about the Galaxy Evolution Explorer is online at
www.nasa.gov/galex and www.galex.caltech.edu .
-end-
From: subscription email
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov
IMAGE ADVISORY: 2008-061 April 16, 2008
A new image from NASA's Galaxy Evolution Explorer shows baby stars sprouting
in the backwoods of a galaxy -- a relatively desolate region of space more
than 100,000 light-years from the galaxy's bustling center.
The striking image, a composite of ultraviolet data from the Galaxy Evolution
Explorer and radio data from the National Science Foundation's Very Large Array
in New Mexico, shows the Southern Pinwheel galaxy, also known simply as M83.
In the new view, the main spiral, or stellar, disk of M83 looks like a pink and
blue pinwheel, while its outer arms appear to flap away from the galaxy like giant
red streamers. It is within these so-called extended galaxy arms that, to the
surprise of astronomers, new stars are forming.
"It is absolutely stunning that we find such an enormous number of young stars up
to 140,000 light-years away from the center of M83," said Frank Bigiel of the Max
Planck Institute for Astronomy in Germany, lead investigator of the new Galaxy
Evolution Explorer observations. For comparison, the diameter of M83 is only
40,000 light-years across.
The new image is online at www.nasa.gov/mission_pag...0080416.html .
Some of the "outback" stars in M83's extended arms were first spotted by the Galaxy
Evolution Explorer in 2005. Remote stars were also discovered around other galaxies
by the ultraviolet telescope over subsequent years. This came as a surprise to
astronomers because the outlying regions of a galaxy are assumed to be relatively
barren and lack high concentrations of the ingredients needed for stars to form.
The newest Galaxy Evolution Explorer observations of M83 (colored blue and green)
were taken over a longer period of time and reveal many more young clusters of stars
at the farthest reaches of the galaxy. To better understand how stars could form in
such unexpected territory, Bigiel and his colleagues turned to radio observations
from the Very Large Array (red). Light emitted in the radio portion of the electromagnetic
spectrum can be used to locate gaseous hydrogen atoms, or raw ingredients of stars. When
the astronomers combined the radio and Galaxy Evolution Explorer data, they were
delighted to see they matched up.
"The degree to which the ultraviolet emission and therefore the distribution of young
stars follows the distribution of the atomic hydrogen gas out to the largest distances
is absolutely remarkable," said Fabian Walter, also of the Max Planck Institute for Astronomy,
who led the radio observations of hydrogen in the galaxy.
The astronomers speculate that the young stars seen far out in M83 could have formed under
conditions resembling those of the early universe, a time when space was not yet enriched
with dust and heavier elements.
"Even with today's most powerful telescopes, it is extremely difficult to study the first
generation of star formation. These new observations provide a unique opportunity to
study how early generation stars might have formed," said co-investigator Mark Seibert
of the Observatories of the Carnegie Institution of Washington in Pasadena.
M83 is located 15 million light-years away in the southern constellation Hydra.
Other investigators include: Barry Madore of The Observatories of the Carnegie Institution
of Washington; Armando Gil de Paz of the Complutense University of Madrid, Spain; David
Thilker of Johns Hopkins University, Baltimore; Elias Brinks of the University of
Hertfordshire, England; and Erwin de Blok of the University of Cape Town, South Africa.
The California Institute of Technology in Pasadena leads the Galaxy Evolution Explorer
mission and is responsible for science operations and data analysis. NASA's Jet Propulsion
Laboratory, also in Pasadena, manages the mission and built the science instrument.
Caltech manages JPL for NASA. The mission was developed under NASA's Explorers Program
managed by NASA's Goddard Space Flight Center, Greenbelt, Md. Researchers sponsored by
Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in
France collaborated on this mission.
The Very Large Array is part of the National Radio Astronomy Observatory, a facility
of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
Additional information about the Galaxy Evolution Explorer is online at
www.nasa.gov/galex and www.galex.caltech.edu .
-end-
From: subscription email
posted by:
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Re: Stellar Birth in the Galactic Wilderness
Wed, April 16, 2008 - 3:15 PMFascinating, a(nother) real mystery. Thanks for the post!
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Re: Stellar Birth in the Galactic Wilderness
Fri, April 18, 2008 - 9:28 AMthat picture is amazing
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Re: Stellar Birth in the Galactic Wilderness
Fri, April 18, 2008 - 11:30 AMWow!
We would have to bring lunch to get out there.
Maybe a tent for over night. -
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Re: Stellar Birth in the Galactic Wilderness
Fri, April 18, 2008 - 12:05 PMtheres a good patent idea...a space tent complete with solar sail and a cooler pocket for snacks
(and hyper drive)
attach it to a jetpack and we're all set
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Re: Stellar Birth in the Galactic Wilderness
Fri, April 18, 2008 - 8:28 PMReminds me of defuse low density galaxies - they're dim, really hard to detect and very large (there was a SciAm article about them years ago. Best to go online and look for the article, ALL my stuff is packed on a truck right now, so I can't look for it). -
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Re: Diffuse Low Density Galaxies
Fri, April 18, 2008 - 9:05 PMI couldn't find anything about the diffuse low density galaxies, but look what else have I found there.
Remember?
_________________________________________________
Scientists reconstruct the Pioneer spacecraft anomaly
By JR Minkel
At the American Physical Society meeting: What is putting a drag on the twin Pioneer spacecraft? Is it uneven heating? Or does gravity deviate from what is expected?
ST. LOUIS—Ten years ago, NASA researchers discovered that the Pioneer 10 and 11 spacecraft had fallen slightly behind course during their 35-year journeys to the outer reaches of the solar system. In what has become known as the Pioneer anomaly, www.sciam.com/article.cfm , which was the subject of one of the talks this weekend at the American Physical Society here in St. Louis, nobody knows for sure why it happened. It probably stemmed from leaking gas or heat.
But there's also the possibility, however remote, that gravity doesn't behave the way we expect. Until recently, researchers haven't had the data to distinguish the different possibilities. That changed in 2006, when NASA physicist Slava Turyshev, science.jpl.nasa.gov/people/Turyshev/ , a co-discoverer of the anomaly, was visiting a colleague at the NASA Ames Research Center. The Moffett Field, Calif.–facility was about to throw out hundreds of magnetic disks, www.planetary.org/programs/...60601.html , containing the Pioneer telemetric data—temperature and power readings that the twin craft had sent back to NASA once every few minutes until they traveled out of range. (NASA finally lost contact with Pioneer 10 in 2003, after 31 years. It had lost contact with Pioneer 11 in 1995.)
Turyshev and his colleagues rescued the data, and Viktor Toth, www.vttoth.com/ , a computer programmer in Ottawa, Ontario, volunteered to write brand new code that extracted the telemetry readings from the raw 1s and 0s encoded in the magnetic disks.
A group of some 50 researchers, including Turyshev, is now trying to match the data to a detailed computer model of the craft's inner workings. The model is designed to mimic the flow of heat and electricity produced by the craft's generators, which harnessed the heat from radioactive plutonium and turned a fraction of it into electricity to power the craft. The remaining heat [see note, www.sciam.com/article.cfm ] was lost to space or spread to other parts of the craft such as the antenna, which influenced each probe's overall momentum.
So far the model accounts for about 30 percent of the observed anomaly for Pioneer 10 at a single distance of 25 astronomical units (2.3 billion miles, or 3.7 billion kilometers) from the sun, Turyshev reported. The group still has to extend the model to other distances and to Pioneer 11. The full verdict may not be in for some time. "I'm trying to ensure we apply every relevant piece of information," Turyshev says. "It is likely that the thermal explanation will explain part of the anomaly," he says, but exactly how much is up for grabs.
He notes that the team is also expanding the original analysis that identified the anomaly from 11 years' worth of transmissions from Pioneer 10, www.sciam.com/article.cfm , and four years from Pioneer 11. Turyshev says the group now has access to 30 and 20 years of data, respectively, and will begin examining it in the coming weeks.
If the anomaly does turn out to have a straightforward explanation, researchers could use it to improve navigation for sensitive space experiments to test gravitational effects, notes programmer Toth. And if not? "If we actually had a means in the solar system here to measure deviations from Einstein's gravity, that would be phenomenal," he says.
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Editor's Note: This article originally stated incorrectly that modeling had explained 30 percent of the Pioneer anomaly up to a distance of 10 astronomical units; and that heat from Pioneer 10 produced 160 watts of power. The average heat energy emitted by the craft was more than two kilowatts.
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Original Publication: www.sciam.com/article.cfm
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Re: Diffuse Low Density Galaxies
Sat, April 19, 2008 - 9:05 PMSerge, I forget how te article is labelled so I'm not surprised you couldn't find it. -
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Re: Diffuse Low Density Galaxies
Sun, April 20, 2008 - 8:35 AMOk, one more time for Troy. :)
Yes, Troy, I understand that. I wasn't looking for a/the particular article. I was looking just for "An" article on that topic (diffuse low density galaxies) in general. After I tried a few variations of spelling out the words "diffuse low density galaxies" I figured, it probably had been deleted or whatever.
But, in the corner of the last screen I was on, I noticed the words Pioneer Mystery, blah-blah, and stuff. So, I immediately recalled our discussion, and everyone interested to read more about this, so I said "Ya-ay!" (no, I didn't "really" said that, but it was close), and had thought, "Oh, I went to look for something else, didn't find that, but instead, found a much better nice surprise; and then, I posted it on tribe.
And that is the meaning of what I had said. :)
(off to screw with Maple again, because the dang "sol:" command doesn't want to "sol:" on him)
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