Infrared Astronomy Archives

February 16, 2011December 24, 2015 by Anne Minard

Galaxy Size Matters … And This is Not a Rorschach Test

False color image of the Lockman-hole area of the sky at infrared wavelengths as imaged by the Herschel Space Observatory. Credit: ESA/SPIRE Consortium/HerMES Consortium

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When it comes to forming stars, the size of a galaxy does matter, according to research out today in the online version of Nature.

But it doesn’t have to be as massive as we once thought.

Alexandre Amblard, an astrophysicist at the University of California, Irvine, and his colleagues used new data from the Herschel Space Observatory to peer into Lockman Hole area of the sky, where extragalactic light comes from star-forming galaxies out of reach for even the world’s most powerful telescopes.

The Lockman Hole is a patch of the sky, 15 square degrees, lying roughly between the pointer stars of the Big Dipper.

Called submillimetre galaxies, the study subjects emit light at wavelengths between the radio and infrared parts of the spectrum, so studying them requires novel approaches borrowing from both radio and optical astronomy. The galaxies by themselves are too blurry to be resolved with individual far-infrared telescopes – but their average properties can be observed and analyzed, which is exactly what Amblard and his colleagues did.

The authors measured variations in the intensity of extragalactic light at far-infrared wavelengths, and derived statistics for the level of clustering of light halos. They assume that the clustering reflects the underlying distribution of dark matter, and fit the data to a halo model of galaxy formation, which connects the spatial distribution of galaxies in the Universe to that of dark matter.

Distribution of dark matter when the Universe was about 3 billion years old, obtained from a numerical simulation of galaxy formation. The left panel displays the continuous distribution of dark matter particles, showing the typical wispy structure of the cosmic web, with a network of sheets and filaments, while the right panel highlights the dark matter halos representing the most efficient cosmic sites for the formation of star-bursting galaxies with a minimum dark matter halo mass of 300 billion times that of the Sun. Credit: VIRGO Consortium/Alexandre Amblard/ESA

Amblard and his colleagues discovered an enormous fact: the ‘haloes’ of dark matter that surround the Universe’s most active star-forming galaxies are each more massive than about 300 billion solar masses.

What’s even more interesting is that the new threshold for star formation is actually smaller than some previous estimates.

“I think there was one prediction that put the number around 5000 billion times that of the sun, but that was just a prediction from a theory of galaxy formation.“ said Asantha Cooray, also an astrophysicist at UC Irvine and second author on the new paper. “The general consensus was that it may be between 100 to 1000 billion times the sun. We now have a more precise answer from this work.”

Cooray said he’s most excited “that we can look at a detailed image of the sky showing distant, star-forming galaxies and infer not only details about the stars and gas in those galaxies but also about the amount of dark matter needed to form such galaxies. Beyond inferring the presence, we still don’t know exactly what dark matter is.”

The results appear online ahead of print today on Nature’s website.

February 11, 2011December 24, 2015 by Nancy Atkinson

Gallery: WISE’s Greatest Hits

WISE First Light image. Image credit: NASA/JPL-Caltech/UCLA

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The WISE mission is now over, with the spacecraft taking its final image on Feb. 1, 2011. WISE was a “cool” infrared mission, with the optics chilled to less than 20 degrees centigrade above absolute zero (20 Kelvins). In its low Earth orbit (523 km above the ground), the spacecraft explored the entire Universe and collected infrared light coming from everywhere in space and studied asteroids, the coolest and dimmest stars, and the most luminous galaxies. Expect to hear and see more from WISE, however in the future. More images will be released from the team in April and in the spring of 2012. Here’s a look back at some of the great images from WISE’s 13 months in space:

The red dot at the center of this image is the first near-Earth asteroid discovered by NASA's Wide-Field Infrared Survey Explorer, or WISE Image credit: NASA/JPL-Caltech/UCLA

The red smudge at the center of this picture is the first comet discovered by NASA's Wide-Field Infrared Survey Explorer, or WISE. Image credit: NASA/JPL-Caltech/UCLA

The immense Andromeda galaxy, also known as Messier 31 or simply M31, is captured in full in this new image from NASA's Wide-field Infrared Survey Explorer, or WISE. credit: NASA/JPL-Caltech/UCLA — The immense Andromeda galaxy, also known as Messier 31 or simply M31, is captured in full in this February 2010 image from WISE. credit: NASA/JPL-Caltech/UCLA

NGC 3603, as seen by WISE. credit: NASA/JPL-Caltech/UCLA

NGC 1514, sometimes called the Crystal Ball nebula shows a new double ring feature in an image from WISE. Image credit: NASA/JPL-Caltech/UCLA

This image from WISE shows the Tadpole nebula. Image credit: NASA/JPL-Caltech/UCLA

The Heart and Soul nebulae are seen in this infrared mosaic from NASA's Wide-field Infrared Survey Explorer, or WISE. Image credit: NASA/JPL-Caltech/UCLA — The Heart and Soul nebulae are seen in this infrared mosaic from WISE. Image credit: NASA/JPL-Caltech/UCLA

A recent WISE image of the Small Magellanic Cloud. Image credit: NASA/JPL-Caltech/WISE Team — An image released in August 2010 from WISE image of the Small Magellanic Cloud. Image credit: NASA/JPL-Caltech/WISE Team

This oddly colorful nebula is the supernova remnant IC 443 as seen by NASA's Wide-field Infrared Survey Explorer, or WISE. Image credit: NASA/JPL-Caltech/UCLA — This oddly colorful nebula is the supernova remnant IC 443 as seen by WISE. Image credit: NASA/JPL-Caltech/UCLA

The last image that will ever be taken by the WISE spacecraft. Credit: NASA/JPL-Caltech/WISE Team

And if you want to see how it all started, here’s a video of WISE’s launch:

February 11, 2011December 24, 2015 by Nancy Atkinson

End of the Line for WISE

What is space made of — The last image that will ever be taken by the WISE spacecraft. Credit: NASA/JPL-Caltech/WISE Team

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First light images from telescopes and spacecraft are exciting – there is the exhilaration that the equipment is working and the anticipation of all the great observations to come. This image has a little different feel to it. On February 1st, 2011, NASA’s Wide-field Infrared Survey Explorer, or WISE, took its last snapshot of the sky. This “last light” image comes after just 13 months of service in space.

This short lifetime was expected: the WISE team knew the cryogen would only last 10 months. WISE launched on Dec. 14, 2009 and there was a 1 month in-orbit check out period, then the 6–month survey, so the team is happy to have had the little extra time with the telescope that they did.

This “last light” image, however, is highly reminiscent of its “first light” image, and shows thousands of stars in a patch of the Milky Way Galaxy, covering an area 3 times the size of the full Moon, in the constellation Perseus. In the upper left corner, a faint wispy cloud can be seen bending around a pulsating variable star called EV Persei.

In the short 13 months that WISE surveyed, it produced millions of infrared images covering the whole sky in its four bands, and covering it twice at 3.4 and 4.6 microns. It studied asteroids, the coolest and dimmest stars, and the most luminous galaxies.

Now that the survey is complete, WISE is being put into hibernation. While the satellite sleeps and circles more than 500 kilometers above the Earth’s surface, the WISE team is busily preparing its data for two big public releases: one this April, and the final release in the spring of 2012. Even though WISE has taken its last picture, the project will continue to feature some of the best imagery from the survey on a regular basis.

The coolant for the spacecraft ran out in October of 2010 and WISE warmed up from -260 degrees to -200 degrees C (-436 to -328 degrees Fahrenheit). This image contains data from the two detectors largely unaffected by the warm-up: 3.4 and 4.6 microns (the 12 and 22 micron detectors are no longer useful at the warmer temperatures).

So long, WISE, and we thank you (but look forward to the public release of your data and more images to come.)

February 10, 2011December 24, 2015 by Nancy Atkinson

Spitzer’s Stunning New View of the North American Nebula

This swirling landscape of stars is known as the North American nebula. In visible light, the region resembles North America, but in this new infrared view from NASA's Spitzer Space Telescope, the continent disappears. Image credit: NASA/JPL-Caltech

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In visible light, the North American nebula resembles its namesake continent. But looking at it in the infrared spectrum, a whole new perspective explodes into view. Clouds of dust and gas come to life, as light from massive young star heats and shape the clouds, and dramatic clusters of baby stars which can only be seen in infrared burst into view.

“One of the things that makes me so excited about this image is how different it is from the visible image, and how much more we can see in the infrared than in the visible,” said Luisa Rebull of NASA’s Spitzer Science Center at the California Institute of Technology, Pasadena, Calif. Rebull is lead author of a paper about the observations, accepted for publication in the Astrophysical Journal Supplement Series. “The Spitzer image reveals a wealth of detail about the dust and the young stars here.”

Rebull and her team have identified more than 2,000 new, candidate young stars in the region. There were only about 200 known before. Because young stars grow up surrounded by blankets of dust, they are hidden in visible-light images. Spitzer’s infrared detectors pick up the glow of the dusty, buried stars.

This new view of the North American nebula combines both visible and infrared light observations, taken by the Digitized Sky Survey and NASA's Spitzer Space Telescope, respectively, into a single vivid picture. Image credit: NASA/JPL-Caltech

Combing infrared data with light from other parts of the spectrum gives astronomers a complete picture of star formation. Each different combination of observations gives insights into star formation.

But in Spitzer’s infrared view, the continent disappears. Instead, a swirling landscape of dust and young stars comes into view.

In this image, astronomers can see stars at all stages of life, from the early years when it is swaddled in dust to early adulthood, when it has become a young parent to a family of developing planets. Sprightly “toddler” stars with jets can also be identified in Spitzer’s view.

“This is a really busy area to image, with stars everywhere, from the North American complex itself, as well as in front of and behind the region,” said Rebull. “We refer to the stars that are not associated with the region as contamination. With Spitzer, we can easily sort this contamination out and clearly distinguish between the young stars in the complex and the older ones that are unrelated.”

There are a couple of mysteries about the North American Nebula still to be solved: astronomers think there must be more stars in the “Gulf of Mexico” region that must dominate the nebula and provide the main source of “power.” There is a dark tangle of clouds there that even Spitzers powerful infrared eyes can’t penetrate, but some light appears to be coming from behind that region, in the same way that sunlight creeps out from behind a rain cloud.

The nebula’s distance from Earth is also a mystery. Current estimates put it at about 1,800 light-years from Earth. Spitzer will refine this number by finding more stellar members of the North American complex.

See more info on the JPL website, where you can download full resolution versions of the images seen here, and more views of the North American nebula.

February 7, 2011April 26, 2016 by Nancy Atkinson

A Galaxy With a Big “S” on Its Chest

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Can galaxy NGC 157 leap tall buildings in a single bound, stop a speeding bullet or bend steel in it’s bare hands? This relatively mild-mannered galaxy has a central sweep of stars that resembles a giant “S”, almost just like the comic book hero Superman’s symbol. The image was taken by the HAWK-I (High-Acuity Wide-field K-band Imager) on the Very Large Telescope in Chile. HAWK-I looks in infrared light, allowing us to peer through the gas and dust that normally obscures our view and see parts of NCG 157 that otherwise is hidden from our optical view.

Looking at this and other galaxies like it, astronomers can learn about star formation, as the same processes that are coalescing material and creating stars in NGC 157 also took place around 4.5 billion years ago in the Milky Way to form our own star, the Sun.

NGC 157 is faint — about magnitude 11, but can be seen bigger amateur telescopes. It is located within the constellation of Cetus (the Sea Monster).

For those interested in observing this object, see this post on WikiSky.

And just in case you don’t get the Superman references:

Source: ESO

January 24, 2011January 19, 2016 by Nancy Atkinson

The Real News about Ophiuchus: There’s a Runaway Star Plowing Through It

The blue star near the center of this image is Zeta Ophiuchi, a runaway star plowing through the constellation Ophiuchus. Credit: NASA/JPL-Caltech/UCLA

Lots of folks seem to be up in arms about the “new” sign in the zodiac, Ophiuchus, and the news that all the star signs are no longer in sync with the actual constellations. Of course, *most* of us already knew that news is centuries old, and that the zodiac has no effect whatsoever on our lives and it never has (most readers of Universe Today, anyway!) Now for some real news about Ophiuchus: NASA’s Wide-field Infrared Survey Explorer, or WISE has found a massive, runaway star, called Zeta Ophiuchi that is plowing through a cloud of space dust in Ophiuchus. The result is a brilliant bow shock, seen here as a yellow arc in this stunning new image.
Continue reading “The Real News about Ophiuchus: There’s a Runaway Star Plowing Through It”

January 13, 2011December 24, 2015 by Tammy Plotner

New Light On Galactic Pair – M81 and M82

A WISE Look At Messier 81 and Messier 82

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Almost every amateur astronomer has viewed the ghostly glow of galactic pair, Messier 81 and Messier 82. They’re easily visible in small binoculars from a dark sky site and reveal wonderful details in a telescope as aperture increases. We’ve marveled over M81’s smooth, star-rich structure and the disturbed spindle-shaped structure of M82. We know the pair have interacted and the huge spiral has ingested stars from its companion – but today we know a whole lot more…

According to today’s press release from the American Astronomical Society, when the pair swept by each other, gravitational interactions triggered new bursts of star formation. In the case of Messier 82, also known as the Cigar Galaxy, the encounter has likely triggered a tremendous wave of new star birth at its core. Intense radiation from newborn massive stars is blowing copious amounts of gas and smoky dust out of the galaxy, as seen in the WISE image in yellow hues. The Cigar Galaxy is pictured above Messier 81. “What’s unique about the WISE view of this duo is that we can see both galaxies in one shot, and we can really see their differences,” said Ned Wright of UCLA, the principal investigator of WISE. “Because the Cigar Galaxy is bursting with star formation, it’s really bright in the infrared, and looks dramatically different from its less active companion.”

The WISE mission completed its main goal of mapping the sky in infrared light in October 2010, covering it one-and-one-half times before its frozen coolant ran out, as planned. During that time, it snapped pictures of hundreds of millions of objects, the first batch of which will be released to the astronomy community in April 2011. WISE is continuing its scan of the skies without coolant using two of its four infrared channels — the two shorter-wavelength channels not affected by the warmer temperatures. The mission’s ongoing survey is now focused primarily on asteroids and comets. Because WISE has imaged the entire sky, it excels at producing large mosaics like this new picture of Messier 81 and Messier 82, which covers a patch of sky equivalent to three-by-three full Moons, or 1.5 by 1.5 degrees.

It is likely these partner galaxies will continue to dance around each other, and eventually merge into a single entity. They are both spiral galaxies, but Messier 82 is seen from an edge-on perspective, and thus appears in visible light as a thin, cigar-like bar. (To me it has always looked like a child’s dirty kite string wrapped around a stick, eh?) When viewed in infrared light, Messier 82 is the brightest galaxy in the sky. It is what scientists refer to as a starburst galaxy because it is churning out large numbers of new stars. “The WISE picture really shows how spectacular Messier 82 shines in the infrared even though it is relatively puny in both size and mass compared to its big brother, Messier 81,” said Tom Jarrett, a member of the WISE team at the California Institute of Technology in Pasadena.

In this WISE view, infrared light has been color coded so that we can see it with our eyes. The shortest wavelengths (3.4 and 3.6 microns) are shown in blue and blue-green, or cyan, and the longer wavelengths (12 and 22 microns) are green and red. Messier 82 appears in yellow hues because its cocoon of dust gives off longer wavelengths of light (the yellow is a result of combining green and red). This dust is made primarily of polycyclic aromatic hydrocarbons, which are found on Earth as soot.

Messier 81, also known as Bode’s Galaxy, appears blue in the infrared image because it is not as dusty. The blue light is from stars in the galaxy. Knots of yellow seen dotting the spiral arms are dusty areas of recent star formation, most likely triggered by the galaxy’s encounter with its rowdy partner. “It’s striking how the same event stimulated a classic spiral galaxy in Messier 81, and a raging starburst in Messier 82,” said WISE Project Scientist Peter Eisenhardt of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “WISE is finding the most extreme starbursts across the whole sky, out to distances over a thousand times greater than Messier 82.”

Next time you view M81 and M82, perhaps you’ll see them in a new light?

Original Source: American Astronomical Society Press Release – WISE Image Credit: NASA
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January 11, 2011January 19, 2016 by Nancy Atkinson

SOFIA Opens New Window on Star Formation in Orion

SOFIA’s mid-infrared image of Messier 42 (right) with comparison images of the same region made at other wavelengths by the Hubble Space Telescope (left) and European Southern Observatory (middle). (Credits: Visible-light image: NASA/ESA/HST/AURA/STScI/O’Dell & Wong; Near-IR image: ESO/McCaughrean et al.; Mid-IR image: NASA/DLR/SOFIA/USRA/DSI/FORCAST Team)

From a NASA Press Release:

A mid-infrared mosaic image from the Stratospheric Observatory for Infrared Astronomy, or SOFIA, offers new information about processes of star formation in and around the nebula Messier 42 in the constellation Orion. The image data were acquired using the Faint Object Infrared Camera for the SOFIA Telescope, or FORCAST, by principal investigator Terry Herter, of Cornell University during SOFIA’s Short Science 1 observing program in December 2010.
Continue reading “SOFIA Opens New Window on Star Formation in Orion”

January 5, 2011December 24, 2015 by Nancy Atkinson

Star Birth and Death in the Andromeda Galaxy

M31, or the Andromeda Galaxy seen in a variety of wavelengths by the Herschel and XMM-Newton space observatories. Credits: infrared: ESA/Herschel/PACS/SPIRE/J. Fritz, U. Gent; X-ray: ESA/XMM-Newton/EPIC/W. Pietsch, MPE; optical: R. Gendle

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To the naked eye, the Andromeda galaxy appears as a smudge of light in the night sky. But to the combined powers of the Herschel and XMM-Newton space observatories, these new images put Andromeda in a new light! Together, the images provide some of the most detailed looks at the closest galaxy to our own. In infrared wavelengths, Herschel sees rings of star formation and XMM-Newton shows dying stars shining X-rays into space.

During Christmas 2010, the two ESA space observatories targeted Andromeda, a.k.a. M31.

Andromeda is about twice as big as the Milky Way but very similar in many ways. Both contain several hundred billion stars. Currently, Andromeda is about 2.2 million light years away from us but the gap is closing at 500,000 km/hour. The two galaxies are on a collision course! In about 3 billion years, the two galaxies will collide, and then over a span of 1 billion years or so after a very intricate gravitational dance, they will merge to form an elliptical galaxy.

Let’s look at each of the images:

Herschel’s view in far-infrared:

Andromeda in far-infrared from Herschel. Credits: ESA/Herschel/PACS/SPIRE/J. Fritz, U. Gent

Sensitive to far-infrared light, Herschel sees clouds of cool dust and gas where stars can form. Inside these clouds are many dusty cocoons containing forming stars, each star pulling itself together in a slow gravitational process that can last for hundreds of millions of years. Once a star reaches a high enough density, it will begin to shine at optical wavelengths. It will emerge from its birth cloud and become visible to ordinary telescopes.

Many galaxies are spiral in shape but Andromeda is interesting because it shows a large ring of dust about 75,000 light-years across encircling the center of the galaxy. Some astronomers speculate that this dust ring may have been formed in a recent collision with another galaxy. This new Herschel image reveals yet more intricate details, with at least five concentric rings of star-forming dust visible.

XMM Newton’s view in X-rays

XMM Newton's view in X-Ray. Credits: ESA/XMM-Newton/EPIC/W. Pietsch, MPE

Superimposed on the infrared image is an X-ray view taken almost simultaneously by ESA’s XMM-Newton observatory. Whereas the infrared shows the beginnings of star formation, X-rays usually show the endpoints of stellar evolution.

XMM-Newton highlights hundreds of X-ray sources within Andromeda, many of them clustered around the centre, where the stars are naturally found to be more crowded together. Some of these are shockwaves and debris rolling through space from exploded stars, others are pairs of stars locked in a gravitational fight to the death.

In these deadly embraces, one star has already died and is pulling gas from its still-living companion. As the gas falls through space, it heats up and gives off X-rays. The living star will eventually be greatly depleted, having much of its mass torn from it by the stronger gravity of its denser partner. As the stellar corpse wraps itself in this stolen gas, it could explode.

Together, the infrared and X-ray images show information that is impossible to collect from the ground because these wavelengths are absorbed by Earth’s atmosphere. Visible light shows us the adult stars, whereas infrared gives us the youngsters and X-rays show those in their death throes.