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The Colliding Spiral Galaxies of Arp 271
Credit & Copyright: Gemini Observatory, GMOS-South, NSF



galaxiesImage1.jpg (30.68 kB . 497x453 - viewed 11760 times)



What will become of these galaxies? Spiral galaxies NGC 5426 and NGC 5427 are passing dangerously close to each other, but each is likely to survive this collision. Most frequently when galaxies collide, a large galaxy eats a much smaller galaxy. In this case, however, the two galaxies are quite similar, each being a sprawling spiral with expansive arms and a compact core. As the galaxies advance over the next tens of millions of years, their component stars are unlikely to collide, although new stars will form in the bunching of gas caused by gravitational tides. Close inspection of the above image taken by the 8-meter Gemini-South Telescope in Chile shows a bridge of material momentarily connecting the two giants. Known collectively as Arp 271, the interacting pair spans about 130,000 light years and lies about 90 million light-years away toward the constellation of Virgo. Quite possibly, our Milky Way Galaxy will undergo a similar collision with the neighboring Andromeda Galaxy in about five billion years.

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Central IC 1805 Cosmic clouds
Credit & Copyright: Keith Quattrocchi


tttImage2.jpg (45.55 kB . 521x453 - viewed 10830 times)

 Cosmic clouds seem to form fantastic shapes in the central regions of emission nebula IC 1805. Of course, the clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster (aka Melotte 15). About 1.5 million years young, the cluster stars appear on the right in this colorful skyscape, along with dark dust clouds silhouetted against glowing atomic gas. A composite of narrow and broad band telescopic images, the view spans about 15 light-years and includes emission from hydrogen in green, sulfur in red, and oxygen in blue hues. Wider field images reveal that IC 1805's simpler, overall outline suggests its popular name - The Heart Nebula. IC 1805 is located about 7,500 light years away toward the constellation Cassiopeia.

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IC 4406: A Seemingly Square Nebula
C. R. O'Dell (Vanderbilt U.) et al., Hubble Heritage Team, NASA



Imsquareage3.jpg (16.37 kB . 421x250 - viewed 10646 times)
 This conundrum comes to light when studying planetary nebulae like IC 4406. Evidence indicates that IC 4406 is likely a hollow cylinder, with its square appearance the result of our vantage point in viewing the cylinder from the side. Were IC 4406 viewed from the top, it would likely look similar to the Ring Nebula. This representative-color picture is a composite made by combining images taken by the Hubble Space Telescope in 2001 and 2002. Hot gas flows out the ends of the cylinder, while filaments of dark dust and molecular gas lace the bounding walls. The star primarily responsible for this interstellar sculpture can be found in the planetary nebula's center. In a few million years, the only thing left visible in IC 4406 will be a fading white dwarf star.

[neilep]

The Milky Way Over Ontario
Credit & Copyright: Kerry-Ann Lecky Hepburn (Weather and Sky Photography)



Image4.jpg (47.86 kB . 385x450 - viewed 10632 times)fter your eyes adapt to the dark, a spectacular sky appears. Such was the case earlier this month over Ontario, Canada, when part of a spectacular sky also became visible in a reflection off a lake. To start, the brightest objects visible are bright stars and the planet Jupiter, seen as the brightest spot on the upper left. A distant town appears as a diffuse glow over the horizon. More faint still, the disk of the Milky Way Galaxy becomes apparent as a dramatic diffuse band across the sky that seems to crash into the horizon far in the distance. In the foreground, a picturesque landscape includes trees, a lake, and a stone wall. Finally, on this serene night in July when the lake water was unusually calm, reflections appear. Visible in the lake are not only reflections of several bright stars, but part of the Milky Way band itself. Careful inspection of the image will reveal, however, that bright stars leave small trails in the lake reflections that do not appear in the sky above. The reason for this is because the above image is actually a digital composite of time-consecutive exposures from the same camera. In the first set of exposures, sky images were co-added with slight rotations to keep the stars in one place

[neilep]

The International Space Station Transits the Sun
Credit & Copyright: Martin Wagner


Image5.jpg (16.19 kB . 444x436 - viewed 10801 times)nspot. It's the International Space Station (ISS) caught by chance passing in front of the Sun. Sunspots, individually, have a dark central umbra, a lighter surrounding penumbra, and no solar panels. By contrast, the ISS is a complex and multi-spired mechanism, one of the largest and most sophisticated machines ever created by humanity. Also, sunspots occur on the Sun, whereas the ISS orbits the Earth. Transiting the Sun is not very unusual for the ISS, which orbits the Earth about every 90 minutes, but getting one's timing and equipment just right for a great image is rare. Strangely, besides that fake spot, the Sun, last week, lacked any real sunspots. Sunspots have been rare on the Sun since the dawn of the current Solar Minimum, a period of low solar activity. Although fewer sunspots have been recorded during this Solar Minimum than for many previous decades, the low solar activity is not, as yet, very unusual.

[neilep]

Moon Games
Credit & Copyright: Laurent Laveder (PixHeaven.net / TWAN)



Image6.jpg (20.44 kB . 497x448 - viewed 10946 times)


The Moon's measured diameter is around 3,476 kilometers (2,160 miles). But apparent angular size, or the angle covered by an object, can also be important to Moon enthusiasts. Angular size depends on distance, the farther away an object is, the smaller an angle it covers. Since the Moon is 400,000 kilometers away, its angular size is only about 1/2 degree, a span easily covered by the tip of your finger held at arms length, or a measuring tape held in the distance by a friend. Of course the Sun is much larger than the Moon, 400 times larger in fact, but today the New Moon will just cover the Sun. The total solar eclipse can be seen along a track across northern Canada, the Arctic, Siberia, and northern China. (A partial eclipse is visible from a broader region). Solar eclipses illustrate the happy coincidence that while the Sun is 400 times the diameter of the Moon, it is also 400 times farther away giving the Sun and Moon exactly the same angular size.

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X-Rays from the Cat's Eye Nebula
Credit: X-ray: NASA/CXC/SAO; Optical: NASA/STScI


Image1.jpg (27.11 kB . 492x476 - viewed 11369 times)tterns within planetary nebula NGC 6543 readily suggest its popular moniker -- the Cat's Eye nebula. Starting in 1995, stunning false-color optical images from the Hubble Space Telescope detailed the swirls of this glowing nebula, known to be the gaseous shroud expelled from a dying sun-like star about 3,000 light-years from Earth. This composite picture combines the latest Hubble optical image of the Cat's Eye with new x-ray data from the orbiting Chandra Observatory and reveals surprisingly intense x-ray emission indicating the presence of extremely hot gas. X-ray emission is shown as blue-purple hues superimposed on the nebula's center. The nebula's central star itself is clearly immersed in the multimillion degree, x-ray emitting gas. Other pockets of x-ray hot gas seem to be bordered by cooler gas emitting strongly at optical wavelengths, a clear indication that expanding hot gas is sculpting the visible Cat's Eye filaments and structures. Gazing into the Cat's Eye, astronomers see the fate of our sun, destined to enter its own planetary nebula phase of evolution ... in about 5 billion years.

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Perseid over Vancouver
Credit & Copyright: Yuichi Takasaka (www.blue-moon.ca / TWAN)



Image2.jpg (49.96 kB . 760x466 - viewed 10809 times)bright, the city lights of Vancouver, Canada are reflected in the water in this portrait of the world at night. Recorded on August 12 during the Perseid Meteor Shower, the wide-angle view takes in a large swath along the photographer's eastern horizon. The picture is a composite of many consecutive 2 second exposures that, when added together, cover a total time of an hour and 33 minutes. During that time, stars trailed through the night sky above Vancouver, their steady motion along concentric arcs a reflection of planet Earth's rotation. The dotted trails of aircraft also cut across the scene. Of course, two of the frames captured the brief, brilliant flash of a Perseid fireball as it tracked across the top of the field of view. The large gap in the single meteor trail corresponds to the time gap between the consecutive frames.

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Brightest star in the galaxy has new competition
NASA/JPL NEWS RELEASE
Posted: July 20, 2008

A contender for the title of brightest star in our Milky Way galaxy has been unearthed in the dusty metropolis of the galaxy's center.



brightest.jpg (50 kB . 398x458 - viewed 10497 times)or=blue]The 'Peony nebula' star, circled,
 is now the second-brightest star
in our galaxy.
Credit: NASA/JPL-Caltech/Potsdam Un[/color][/b][/size]iv.
 
 
Nicknamed the "Peony nebula star," the bright stellar bulb was revealed by NASA's Spitzer Space Telescope and other ground-based telescopes. It blazes with the light of an estimated 3.2 million suns.

The reigning "brightest star" champion is Eta Carina, with a whopping solar wattage of 4.7 million suns. But according to astronomers, it's hard to pin down an exact brightness, or luminosity, for these scorching stars, so they could potentially shine with a similar amount of light.

"The Peony nebula star is a fascinating creature. It appears to be the second-brightest star that we now know of in the galaxy, and it's located deep into the galaxy's center," said Lidia Oskinova of Potsdam University in Germany. "There are probably other stars just as bright if not brighter in our galaxy that remain hidden from view." Oskinova is principal investigator for the research and second author of a paper appearing in a future issue of the journal Astronomy and Astrophysics.

Scientists already knew about the Peony nebula star, but because of its sheltered location in the dusty central hub of our galaxy, its extreme luminosity was not revealed until now. Spitzer's dust-piercing infrared eyes can see straight into the heart of our galaxy, into regions impenetrable by visible light. Likewise, infrared data from the European Southern Observatory's New Technology Telescope in Chile were integral in calculating the Peony nebula star's luminosity.

"Infrared astronomy opens extraordinary views into the environment of the central region of our galaxy," said Oskinova.

The brightest stars in the universe are also the biggest. Astronomers estimate the Peony nebula star kicked off its life with a hefty mass of roughly 150 to 200 times that of our sun. Stars this massive are rare and puzzle astronomers because they push the limits required for stars to form. Theory predicts that if a star starts out too massive, it can't hold itself together and must break into a double or multiple stars instead.

Not only is the Peony nebula star hefty, it also has a wide girth. It is a type of giant blue star called a Wolf-Rayet star, with a diameter roughly 100 times that of our sun. That means this star, if placed where our sun is, would extend out to about the orbit of Mercury.

With so much mass, the star barely keeps itself together. It sheds an enormous amount of stellar matter in the form of strong winds over its relatively short lifetime of a few million years. This matter is pushed so hard by strong radiation from the star that the winds speed up to about 1.6 million kilometers per hour (one million miles per hour) in only a few hours.

Ultimately, the Peony nebula star will blow up in a fantastic explosion of cosmic proportions called a supernova. In fact, Oskinova and her colleagues say that the star is ripe for exploding soon, which in astronomical terms mean anytime from now to millions of years from now.

"When this star blows up, it will evaporate any planets orbiting stars in the vicinity," said Oskinova. "Farther out from the star, the explosion could actually trigger the birth of new stars."

In addition to the star itself, the astronomers noted a cloud of dust and gas, called a nebula, surrounding the star. The team nicknamed this cloud the Peony nebula because it resembles the ornate flower.

"The nebula was probably created from the spray of dust leaking off the massive Peony nebula star," said Andreas Barniske of Potsdam University, lead author of the study.

Wolf-Rainer Hamann, also of Potsdam University, is another co-author of the paper and the principal investigator of a Spitzer program enabling this research.

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A new way developed to weigh giant black holes
CHANDRA X-RAY CENTER NEWS RELEASE
Posted: July 19, 2008

How do you weigh the biggest black holes in the universe? One answer now comes from a completely new and independent technique that astronomers have developed using data from NASA's Chandra X-ray Observatory.


chandra.jpg (11.84 kB . 398x398 - viewed 10498 times)
Credit: X-ray (NASA/CXC/Univ. of
California Irvine/P.Humphrey et al.); Optical (NASA/STScI)
 
 
By measuring a peak in the temperature of hot gas in the center of the giant elliptical galaxy NGC 4649, scientists have determined the mass of the galaxy's supermassive black hole. The method, applied for the first time, gives results that are consistent with a traditional technique.

Astronomers have been seeking out different, independent ways of precisely weighing the largest supermassive black holes, that is, those that are billions of times more massive than the Sun. Until now, methods based on observations of the motions of stars or of gas in a disk near such large black holes had been used.

"This is tremendously important work since black holes can be elusive, and there are only a couple of ways to weigh them accurately," said Philip Humphrey of the University of California at Irvine, who led the study. "It's reassuring that two very different ways to measure the mass of a big black hole give such similar answers."

NGC 4649 is now one of only a handful of galaxies for which the mass of a supermassive black hole has been measured with two different methods. In addition, this new X-ray technique confirms that the supermassive black hole in NGC 4649 is one of the largest in the local universe with a mass about 3.4 billion times that of the Sun, about a thousand times bigger than the black hole at the center of our galaxy.

The new technique takes advantage of the gravitational influence the black hole has on the hot gas near the center of the galaxy. As gas slowly settles towards the black hole, it gets compressed and heated. This causes a peak in the temperature of the gas right near the center of the galaxy. The more massive the black hole, the bigger the temperature peak detected by Chandra.

This effect was predicted by two of the co-authors -- Fabrizio Brighenti from the University of Bologna, Italy, and William Mathews from the University of California at Santa Cruz -- almost 10 years ago, but this is the first time it has been seen and used.

"It was wonderful to finally see convincing evidence of the effects of the huge black hole that we expected," said Brighenti. "We were thrilled that our new technique worked just as well as the more traditional approach for weighing the black hole."

The black hole in NGC 4649 is in a state where it does not appear to be rapidly pulling in material towards its event horizon, nor generating copious amounts of light as it grows. So, the presence and mass of the central black hole has to be studied more indirectly by tracking its effects on stars and gas surrounding it. This technique is well suited to black holes in this condition.

"Monster black holes like this one power spectacular light shows in the distant, early universe, but not in the local universe," said Humphrey. "So, we can't wait to apply our new method to other nearby galaxies harboring such inconspicuous black holes."

source:spaceflightnow.org

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Using gravitational lensing to weigh 70 galaxies
UNIVERSITY OF HAWAII NEWS RELEASE
Posted: July 22, 2008

An international team of astronomers, including Dr. Adam S. Bolton of the University of Hawaii's Institute for Astronomy, has recently announced a finding that helps to settle a long-standing debate over the relationship between mass (the amount of matter) and luminosity (brightness) in galaxies.

galaxies.jpg (15.88 kB . 398x299 - viewed 10475 times)
The larger panel shows the Hubble Space Telescope
 image of one of the SLACS gravitational lenses,
 with the lensed background galaxy enhanced in blue.
 The smaller right-hand panels show the components
of a model of this image: top, a model for how the
more distant background galaxy would appear in the
absence of the lensing effect; center, a smooth model
 for the brightness of the more nearby massive galaxy;
bottom, the appearance of the background galaxy when
its image is distorted by the gravity of the nearer
galaxy. Credit: A. Bolton (UH/IfA) for SLACS and NASA/ESA[/b]
 
 
The team achieved this result by compiling the largest-ever single collection of "gravitational lens" galaxies-70 in all. A gravitational lens is a phenomenon similar to a terrestrial mirage, but it occurs on a scale of many thousands of light-years. When two galaxies happen to be precisely aligned with one another in the sky, the gravitational field of the nearer galaxy distorts the image of the more distant galaxy into multiple arc-shaped images or even into a complete ring, known as an "Einstein ring." These Einstein ring images can be up to 30 times brighter than the image of the distant galaxy would be in the absence of the lensing effect.

The discovery represents the culmination of the Sloan Lens ACS (or SLACS) Survey. The gravitational lenses were originally identified using data from the Sloan Digital Sky Survey, a major project that has used a dedicated 2.5-meter telescope in New Mexico to measure precise distances to nearly one million distant galaxies and quasars throughout one quarter of the sky. To observe and measure the details of the Einstein ring images, the SLACS astronomers then took advantage of the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope, which delivers pictures of unparalleled sharpness.

"The SLACS collection of lenses is especially powerful for science," said Bolton, lead author of two papers describing these latest results, which will be published in the Astrophysical Journal in August and September. "For each lens, we measured the apparent sizes of the Einstein rings on the sky using the Hubble images, and we measured the distances to the two galaxies of the aligned pair using Sloan data. By combining these measurements, we were able to deduce the mass of the nearer galaxy."

In other lens surveys of this scale, distances to the lens and background galaxies-and hence the lens galaxy masses-have not been measured precisely.

By considering these galaxy masses along with measurements of their sizes, brightnesses, and stellar velocities, the SLACS astronomers were able to infer the presence of "dark matter" in addition to the visible stars within the galaxies. Dark matter is the mysterious, unseeable material that is the majority of matter in the universe. And with such a large number of lens galaxies across a range of masses, they found that the fraction of dark matter relative to stars increases systematically when going from galaxies of average mass to galaxies of high mass.

The existence of gravitational lenses was first predicted by Albert Einstein in the 1930s, but the first example was not discovered until the late 1970s. In the 30 years since then, many more lenses have been discovered, but their scientific potential has been limited by the disparate assortment of known examples. The SLACS Survey has significantly changed this situation by discovering a single large and uniformly selected sample of strong lens galaxies. The SLACS collection promises to form the basis of many further scientific studies.

Other members of the SLACS collaboration are Dr. L.V.E. Koopmans (Kapteyn Instituut, Groningen, The Netherlands), Prof. Tommaso Treu (University of California, Santa Barbara), Dr. Raphael Gavazzi (Institut d'astrophysique de Paris), Dr. Leonidas A. Moustakas (JPL/Caltech), and Dr. Scott Burles (MIT).

Founded in 1967, the Institute for Astronomy at the University of Hawaii at Manoa conducts research into galaxies, cosmology, stars, planets, and the sun. Its faculty and staff are also involved in astronomy education, deep space missions, and in the development and management of the observatories on Haleakala and Mauna Kea.

Established in 1907 and fully accredited by the Western Association of Schools and Colleges, the University of Hawaii is the state's sole public system of higher education. The UH System provides an array of undergraduate, graduate, and professional degrees and community programs on 10 campuses and through educational, training, and research centers across the state. UH enrolls more than 50,000 students from Hawaii, the U.S. mainland, and around the world.

Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England.

This work was based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc. Support was provided by NASA through grants from STScI.


SOURCE:SPACEFLIGHTNOW.ORG

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The first stars
HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS NEWS RELEASE
Posted: July 31, 2008

The universe began with the Big Bang about 13.7 billion years ago. Very soon after that event, the first stars formed. Today, those stars are dead and gone leaving little evidence of their size and composition behind. Now, a new computer simulation now offers the most detailed picture yet of how these first stars came into existence. These findings will be published by the journal Science on Friday, 1 August.


firststars.jpg (13.88 kB . 398x331 - viewed 10208 times)In this artist impression, swirling clouds
of hydrogen and helium gasses are illuminated
 by the first starlight to shine in the Universe.
 In the lower portion of the artwork, a supernova
explodes ejecting heavier elements that will someday
be incorporated into new stars and planets.
 Credit: David A. Aguilar, CfA[/b][/color]
 
 
The composition of the early universe was quite different from that of today, and the physics that governed the early universe were also somewhat simpler. Dr. Naoki Yoshida, Nagoya University in Nagoya, Japan and co-author Dr. Lars Hernquist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, incorporated these conditions of the early universe, sometimes referred to as the "cosmic dark ages," to simulate the formation of an astronomical object that would eventually shine as a star.

According to their simulations, gravity acted on minute density variations in matter, gases, and the mysterious "dark matter" of the universe after the Big Bang in order to form the early stages of a star called a protostar. With a mass of just one percent of our Sun, Dr. Yoshida's simulation also shows that the protostar would likely evolve into a massive star capable of synthesizing heavy elements, not just in later generations of stars, but soon after the Big Bang. These stars would have been up to one hundred times as massive as our Sun and would have burned for no more than one million years.

"This general picture of star formation, and the ability to compare how stellar objects form in different time periods and regions of the universe, will eventually allow investigation in the origins of life and planets," said Hernquist.

"The abundance of elements in the Universe has increased as stars have accumulated," he says, "and the formation and destruction of stars continues to spread these elements further across the Universe. So when you think about it, all of the elements in our bodies originally formed from nuclear reactions in the centers of stars, long ago."

Their simulation of the birth of a protostar in the early universe signifies a key step toward the ambitious goal of piecing together the formation of an entire primordial star and of predicting the mass and properties of these first stars of the universe. More powerful computers, more physical data, and an even larger range will be needed for further calculations and simulations, but these researchers hope to eventually extend this simulation to the point of nuclear reaction initiation ­ when a stellar object becomes a true star.

"Dr. Yoshida has taken the study of primordial star formation to a new level with this simulation, but it still gets us only to the halfway point towards our final goal. It is like laying the foundation of a skyscraper," said Volker Bromm, Assistant Professor of Astronomy at the University of Texas, Austin and the author of a companion article. "We must continue our studies in this area to understand how the initially tiny protostar grows, layer by layer, to eventually form a massive star. But here, the physics become much more complicated and even more computational resources are needed."

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe


SOURCE:SPACEFLIGHTNOW.ORG

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'Cosmic ghost' discovered by volunteer astronomer
YALE UNIVERSITY NEWS RELEASE
Posted: August 5, 2008

NEW HAVEN, Conn. - When Yale astrophysicist Kevin Schawinski and his colleagues at Oxford University enlisted public support in cataloguing galaxies, they never envisioned the strange object Hanny van Arkel found in archived images of the night sky.


lightecho.jpg (41.02 kB . 398x439 - viewed 10283 times)size=7pt]Hanny's Voorwerp: the green blob of gas
 believed to be a 'light echo' from the
bright, stormy centre of a distant galaxy
that has now gone dim.
 Credit : Dan Smith, Peter Herbert, Matt Jarvis & the ING [/size][/b][/color]
 
 
The Dutch school teacher, a volunteer in the Galaxy Zoo project that allows members of the public to take part in astronomy research online, discovered a mysterious and unique object some observers are calling a "cosmic ghost."

van Arkel came across the image of a strange, gaseous object with a hole in the center while using the www.galaxyzoo.org website to classify images of galaxies.

When she posted about the image that quickly became known as "Hanny's Voorwerp" ( Dutch for "object") on the Galaxy Zoo forum, astronomers who run the site began to investigate and soon realized van Arkel might have found a new class of astronomical object.

"At first, we had no idea what it was. It could have been in our solar system, or at the edge of the universe," said Schawinski, a member and co-founder of the Galaxy Zoo team.

Scientists working at telescopes around the world and with satellites in space were asked to take a look at the mysterious Voorwerp. "What we saw was really a mystery," said Schawinski. "The Voorwerp didn't contain any stars." Rather, it was made entirely of gas so hot - about 10,000 Celsius - that the astronomers felt it had to be illuminated by something powerful. They will soon use the Hubble Space Telescope to get a closer look.

Since there was no obvious source at hand in the Voorwerp itself, the team looked to find the source of illumination around the Voorwerp, and soon turned to the nearby galaxy IC 2497.

"We think that in the recent past the galaxy IC 2497 hosted an enormously bright quasar," Schawinski explains. "Because of the vast scale of the galaxy and the Voorwerp, light from that past still lights up the nearby Voorwerp even though the quasar shut down sometime in the past 100,000 years, and the galaxy's black hole itself has gone quiet."

"From the point of view of the Voorwerp, the galaxy looks as bright as it would have before the black hole turned off ­ it's this light echo that has been frozen in time for us to observe," said Chris Lintott, a co-organizer of Galaxy Zoo at Oxford University, UK. "It's rather like examining the scene of a crime where, although we can't see them, we know the culprit must be lurking somewhere nearby in the shadows." Similar light echoes have been seen around supernovae that exploded decades or centuries ago.

Quasars are very unusual, highly luminous objects, powered by supermassive black holes, and most are extremely distant. "The strange 'Hanny's Voorwerp' looks like it could be the nearest example of a luminous quasar," said C. Megan Urry, Israel Munson Professor of Physics & Astronomy and Chair of the Physics Department at Yale, who was not involved in the research.

"IC 2497 is so close that if the quasar was still shining today, on a good night you could probably see it with a small telescope," Schawinski added. "The nearest active quasar, called 3C 273, is 1.7 billion light years further away."

"This discovery really shows how citizen science has come of age in the Internet world," commented Professor Bill Keel of the University of Alabama, a galaxyzoo.org team member. "Hanny's attentiveness alerted us not only to a peculiar object, but to a window into the cosmic past which might have eluded us for a long time otherwise. Trying to understand the processes operating here has proven to be a fascinating challenge, involving a whole range of astrophysical techniques and instruments around the world and beyond. This has also been some of the most rewarding astronomy I've done in years!"

The Galaxy Zoo project was imagined and begun by Schawinski and his colleague Chris Lintott at Oxford. While working on his PhD thesis, Schawinski classified and catalogued nearly 50,000 galaxies. Knowing that the human eye is sometimes more sensitive than a computer at picking out unusual patterns, he mused that it would be wonderful if there were amateur astronomers who were interested in doing some of the "scanning."

"When we launched Galaxy Zoo we were overwhelmed - as was the internet portal, initially - with the outpouring of public interest and volunteer input," said Schawinski. During the last year, over 150,000 armchair astronomers from all over the world volunteered their time and submitted over 50 million classifications for a set of one million images online. They then could follow the progress of the science they made possible at www.galaxyzooblog.org

"It's amazing to think that this object has been sitting in the archives for decades and that amateur volunteers can help by spotting things like this online," said Hanny van Arkel. "It was a fantastic present to find out on my 25th birthday that we will get observational time on the Hubble Space Telescope to follow-up this discovery."

 SOURCE:SPACEFLIGHTNOW.ORG

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Generations of stars pose for family portrait
BY DR EMILY BALDWIN
ASTRONOMY NOW


Posted: August 26, 2008

In celebration of Spitzer’s five years in orbit, a stunning new image reveals the family portrait of a star-forming inferno studded with multiple generations of brilliant stars, and provides dramatic new evidence that massive stars can trigger the birth of stellar newborns through their savage winds and radiation.

"Triggered star formation continues to be very hard to prove," says Xavier Koenig of the Harvard Smithsonian Centre for Astrophysics, "but our preliminary analysis shows that the phenomenon can explain the multiple generations of stars seen in the W5 region."



080826spitzer.jpg (87.1 kB . 398x566 - viewed 10595 times)
The Spitzer image was taken over a period of 24 hours and is a three-colour composite showing infrared observations from two Spitzer instruments. Blue represents 3.6-micron light and are older stars in the star-forming cloud as well as unrelated stars behind and in front of the cloud, and green shows light of 8 microns, highlighting dense clouds, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer and shows heated dust that pervades the region's cavities. White knotty areas are where the youngest stars are forming. Image: NASA/JPL-Caltech/Harvard-Smithsonian CfA.

W5 spans an area of sky equivalent to four full moons and is about 6,500 light-years away in the constellation Cassiopeia. Like other massive star-forming regions such as Orion and Carina, W5 hosts vast cavities that were carved out by blistering radiation and ferocious winds from the region's most massive stars. According to the theory of triggered star-formation, the sculpting of these cavities forces gas together, causing it to ignite into successive generations of new stars along the cavities' expanding rims. The result is a radial family tree of stars, with the oldest in the middle of the cavity, and younger stars further out.

Koenig and colleagues set out to test the triggered star-formation theory by studying the ages of the stars in W5. They used Spitzer's penetrating infrared vision to peer through the dusty clouds and view the stars' various stages of evolution. They found that stars within the W5 cavities (blue dots) are older than stars at the rims (pink and white dots) and even older than stars further out past the rim that are embedded in the elephant trunk-like pillars of gas. This ladder-like separation of ages provides some of the best evidence yet that massive stars do, in fact, give rise to younger generations.

"Our first look at this region suggests we are looking at one or two generations of stars that were triggered by the massive stars," says co-author Lori Allen. However, it is possible that the younger stars just happen to be near the edge of the cavities and were not triggered by the larger stars and so the research team plan to follow up with even more detailed measurements of the stars' ages to find out if there is a distinct time gap between the stars just inside and outside the rim.

And in a serious twist of fate, the massive stars in W5 will eventually die in tremendous explosions, wiping out some of the very stars that they triggered into existence millions of years previously.

SOURCE:SPACEFLIGHTNOW.ORG
 

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Milky Way Road Trip
Credit & Copyright: Tunç Tezel (TWAN)



smalluludag_tezel.jpg (58.85 kB . 928x466 - viewed 12559 times)wrp.gsfc.nasa.gov/apod/image/0809/uludag_tezel.jpg]BIGGY PICCY HERE[/url]



 In search of planets and the summer Milky Way, astronomer Tunç Tezel took an evening road trip. Last Saturday, after driving the winding road up Uludag, a mountain near Bursa, Turkey, he was rewarded by this beautiful skyview to the south. Near the center, bright planet Jupiter outshines the city lights below and the stars of the constellation Sagittarius. Above the mountain peaks, an arcing cloud bank seems to lead to the Milky Way's own cloudy apparition plunging into the distant horizon. In Turkish, Uludag means Great Mountain. Uludag was known in ancient times as the Mysian Olympus.

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A Flock of Stars
Credit & Copyright: Roger A. Hopkins




Iffffmage1.jpg (39.64 kB . 630x473 - viewed 10212 times)stars can be found within ten light-years of our lonely Sun, situated near an outer spiral arm of the Milky Way galaxy. But if the Sun were found within one of our galaxy's star clusters, thousands of stars might occupy a similar space. What would the night sky look like in such a densely packed stellar neighborhood? When Roger Hopkins took this picture at the Montezuma National Wildlife Refuge in the Finger Lakes region of western New York, USA, he was struck by this same notion. Appropriately, he had photographed a flock of starlings against the backdrop of a serene sunset. He then manipulated the image so that the black bird silhouettes were changed to white. The final picture dramatically suggests the tantalizing spectacle of approaching night in crowded skies above a cluster star world.

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M110: Satellite of the Andromeda Galaxy
Credit & Copyright: Jean-Charles Cuillandre (CFHT) & Giovanni Anselmi (Coelum Astronomia), Hawaiian Starlight


m110_cfht_big1.jpg (116.76 kB . 621x692 - viewed 10275 times)ay Galaxy is not alone. It is part of a gathering of about 25 galaxies known as the Local Group. Members include the Great Andromeda Galaxy (M31), M32, M33, the Large Magellanic Cloud, the Small Magellanic Cloud, Dwingeloo 1, several small irregular galaxies, and many dwarf elliptical and dwarf spheroidal galaxies. Pictured on the lower right is one of the dwarf ellipticals: NGC 205. Like M32, NGC 205 is a companion to the large M31, and can sometimes be seen to the south of M31's center in photographs. The image shows NGC 205 to be unusual for an elliptical galaxy in that it contains at least two dust clouds (at 9 and 2 o'clock - they are visible but hard to spot) and signs of recent star formation. This galaxy is sometimes known as M110, although it was actually not part of Messier's original catalog.

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SN 1006: A Supernova Ribbon from Hubble
Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Acknowledgement: W. Blair et al. (JHU)




Imrrrge1.jpg (67.1 kB . 781x589 - viewed 10213 times)is unusual space ribbon? Most assuredly, one of the most violent explosions ever witnessed by ancient humans. Back in the year 1006 AD, light reached Earth from a stellar explosion in the constellation of the Wolf (Lupus), creating a "guest star" in the sky that appeared brighter than Venus and lasted for over two years. The supernova, now cataloged at SN 1006, occurred about 7,000 light years away and has left a large remnant that continues to expand and fade today. Pictured above is a small part of that expanding supernova remnant dominated by a thin and outwardly moving shock front that heats and ionizes surrounding ambient gas. SN 1006 now has a diameter of nearly 60 light years. Within the past year, an even more powerful explosion occurred far across the universe that was visible to modern humans, without any optical aid, for a few seconds.

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Active Region 1002 on an Unusually Quiet Sun
Credit: SOHO Consortium, EIT, ESA, NASA


sunspot1002_soho.jpg (32.56 kB . 376x300 - viewed 10085 times)Sun been so quiet recently? No one is sure. Our Sun has shown few active regions -- that house even fewer associated sunspots -- for over a year now, and such a period of relative calm is quite unusual. What is well known is that our Sun is in a transitional period between solar cycles called a Solar Minimum, where solar activity has historically been reduced. The stark lack of surface tumult is unusual even during a Solar Minimum, however, and activity this low has not been seen for many decades. A few days ago, however, a bona-fide active region -- complete with sunspots --appeared and continues to rotate across the Sun's face. Visible above, this region, dubbed Active Region 1002 (AR 1002), was imaged in ultraviolet light yesterday by the SOHO spacecraft, which co-orbits the Sun near the Earth. Besides the tranquility on the Sun's surface, recent data from the Ulysses spacecraft, across the Solar System, indicate that the intensity of the solar wind blowing out from the Sun is at a fifty year low. Predictions hold, however, that our Sun will show more and more active regions containing more and more sunspots and flares until Solar Maximum occurs in about four years.

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Prehistoric funerary precinct excavated in northern Israel

Grave goods include phallic figurines, sea shells from Mediterranean and Red Seas, items from Syria, Cyprus and Anatolia




Hebrew University excavations in the north of Israel have revealed a prehistoric funerary precinct dating back to 6,750-8,500 BCE.

The precinct, a massive walled enclosure measuring 10 meters by at least 20 meters, was discovered at excavations being undertaken at Kfar HaHoresh. The Pre-Pottery Neolithic B site in the Nazareth hills of the lower Galilee is interpreted as having been a regional funerary and cult center for nearby lowland villages.

Prof. Nigel Goring-Morris of the Hebrew University's Institute of Archaeology, who is leading the excavations, says that the precinct is just one of the many finds discovered at the site this year – including remains of a fully-articulated, but tightly contracted 40 year old adult male.



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(1) Phallic figurine,
 (2) Small symbolic axe made with serpentine,
 (3) Shell pendants,
 (4) Engraved token



Accompanying grave goods include a sickle blade and a sea shell, while a concentration of some 60 other shells were found nearby. The sea shells provide evidence for extensive exchange networks from the Mediterranean and Red Seas. Symbolic items include small plain or incised tokens. An entire herd of cattle was also found buried nearby.




9723_web.jpg (26.48 kB . 400x287 - viewed 9950 times)Aerial view over the funerary precinct.[/size][/color]


While fertility symbols during this period are often associated with female imagery, at Kfar HaHoresh only phallic figurines have been found to date, including one placed as a foundation deposit in the wall of the precinct.

Exotic minerals found at the site include malachite from south of the Dead Sea, obsidian (natural volcanic glass) from central Anatolia, and a votive axe on serpentine from either Cyprus or northern Syria.

"Cultic artifacts, installations and their contextual associations attest to intensive ritual practices in the area," says Prof. Goring-Morris.




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Grave of complete body with shell, knife and sickle


Burials at the site now total at least 65 individuals, and display an unusual demographic profile – with an emphasis on young adult males. Graves occur under or associated with lime-plaster surfaced L-shaped walled structures, and are varied in nature from single articulated burials through multiple secondary burials with up to 17 individuals. Bones in one had been intentionally re-arranged in what appears to be a depiction.

The Pre-pottery Neolithic B, ca. 8,500-6,750 BCE, corresponds to the period when the first large village communities were established in the fertile regions of the Near East when a wide ranging cultural interaction sphere came into being throughout the Levant.

SOURCE: EUREKA ALERT