Anne Minard is a freelance science journalist with an academic background in biology and a fascination with outer space. Her first book, Pluto and Beyond, was published in 2007.
Most stars exist in binary pairs today — and new research indicates that may have been true for a very long time. This simulation of a primordial star forming region about 200 million years after the Big Bang shows two pre-stellar cores of more than five times the mass of the sun each. The cores formed at a separation of 800 times the distance from the Earth to the Sun, and are expected to evolve into a binary star system.
Most previous simulations of the early universe, in which clouds of primordial gas collapsed to form the first luminous objects, suggest that early stars formed separately from each other.
Lead author Matthew Turk, of Stanford University, and his colleagues performed computer simulations during which a central clump of primordial material about 50 times the mass of the Sun breaks into two cores with a mass ratio of two to one. Both are able to cool and plump up, by accreting matter from the surrounding cold gas reservoir, “and will likely form a binary star system,” the authors write.
The findings may also have implications for detecting both gravity waves — disturbances predicted by general relativity, which haven’t yet been detected directly — and the ultra-energetic explosions known as gamma ray bursts, since binary systems are thought to be at the origins of both of these phenomena.
The results are in this week’s issue of the journal Science and appear online today at the Science Express website.
Three-colour composite image of the Omega Nebula (Messier 17), based on images obtained with the EMMI instrument on the ESO 3.58-metre New Technology Telescope at the La Silla Observatory.
[/caption]
The Omega Nebula, a stellar nursery 5500 light-years away towards the constellation Sagittarius (the Archer), is looking positively dashing in this new image released today by the European Organisation for Astronomical Research in the Southern Hemisphere (ESO). The subtle color shades across the three-color composite image comes from the presence of different gases (mostly hydrogen, but also oxygen, nitrogen and sulfur) that are glowing under the fierce ultraviolet light radiated by hot young stars.
The Omega Nebula, sometimes called the Swan Nebula, is an active star-forming region of gas and dust about 15 light-years across that has recently spawned a cluster of massive, hot stars. The intense light and strong winds from these hulking infants have carved the filigree structures in the gas and dust.
When seen through a small telescope, the nebula has a shape that reminds some observers of the final letter of the Greek alphabet, omega, while others see a swan with its distinctive long, curved neck. Other nicknames for this evocative cosmic landmark include the Horseshoe and the Lobster Nebula.
Swiss astronomer Jean-Philippe Loys de Cheseaux discovered the nebula around 1745. The French comet hunter Charles Messier independently rediscovered it about twenty years later and included it as number 17 in his famous catalogue. In a small telescope, the Omega Nebula appears as an enigmatic ghostly bar of light set against the star fields of the Milky Way. Early observers were unsure whether this curiosity was really a cloud of gas or a remote cluster of stars too faint to be resolved. In 1866, William Huggins settled the debate when he confirmed the Omega Nebula to be a cloud of glowing gas, through the use of a new instrument, the astronomical spectrograph.
In recent years, astronomers have discovered that the Omega Nebula is one of the youngest and most massive star-forming regions in the Milky Way.
More about the image: It was based on images obtained with the EMMI instrument on the ESO 3.58-metre New Technology Telescope at the La Silla Observatory.
ESO has also released two videos. You can zoom in on the Omega Nebula, or pan across it (with musical accompaniment).
Courtesy of the National Astronomical Observatory of Japan
[/caption]
Astronomers working with the Subaru Telescope have released these new images of a “fireworks display” in a near-infrared image of the Helix Nebula, showing comet-shaped knots within.
Enlarged image, showing an enormous number of knots. The size of each knot is about five times as big as Pluto’s orbit in the Solar System
The Helix Nebula, NGC 7293, is not only one of the most interesting and beautiful planetary nebulae; it is also one of the closest nebulae to Earth, at a distance of only 710 light years away. The new image, taken with an infrared camera on the Subaru Telescope in Hawaii, shows tens of thousands of previously unseen comet-shaped knots inside the nebula. The sheer number of knots–more than have ever been seen before—looks like a massive fireworks display in space.
The Helix Nebula was the first planetary nebula in which knots were seen, and their presence may provide clues to what planetary material may survive at the end of a star’s life. Planetary nebulae are the final stages in the lives of low-mass stars, such as our Sun. As they reach the ends of their lives they throw off large amounts of material into space. Although the nebula looks like a fireworks display, the process of developing a nebula is neither explosive nor instantaneous; it takes place slowly, over a period of about 10,000 to 1,000,000 years. This gradual process creates these nebulae by exposing their inner cores, where nuclear burning once took place and from which bright ultraviolet radiation illuminates the ejected material.
Astronomers from the National Astronomical Observatory of Japan (NAOJ), from London, Manchester and Kent universities in the UK and from the University of Missouri in the US studied the emissions from hydrogen molecules in the infrared and found that knots are found throughout the entire nebula. Although these molecules are often destroyed by ultraviolet radiation in space, they have survived in these knots, shielded by dust and gas that can be seen in optical images. The comet-like shape of these knots results from the steady evaporation of gas from the knots, produced by the strong winds and ultraviolet radiation from the dying star in the center of the nebula.
Unlike previous optical images of the Helix Nebula knots, the infrared image shows thousands of clearly resolved knots, extending out from the central star at greater distances than previously observed. The extent of the cometary tails varies with the distance from the central star, just as Solar System comets have larger tails when they are closer to the Sun and when wind and radiation are stronger. “This research shows how the central star slowly destroys the knots and highlights the places where molecular and atomic material can be found in space,”says lead astronomer Dr. Mikako Matsuura, previously at NAOJ and now from University College London.
These images enable astronomers to estimate that there may be as many as 40,000 knots in the entire nebula, each of which are billions of kilometers/miles across. Their total mass may be as much as 30,000 Earths, or one-tenth the mass of our Sun. The origin of the knots is currently unknown.
This paper will be published in the Astrophysical Journal in August 2009
Final image caption: Previous optical image of the Helix Nebula, demonstrating diffuse gas surrounding a central star. The white box shows the area observed by the Subaru Telescope. Credit: NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner [STScI], and T.A. Rector [NRAO]
This all-sky map shows the positions of 16 new pulsars (yellow) and eight millisecond pulsars (magenta) studied using Fermi's LAT. Credit: NASA/DOE/Fermi LAT Collaboration
[/caption]
For the first time, NASA’s Fermi Gamma-ray Space Telescope has spotted a new group of pulsars using only their gamma-ray emissions, in the absence of radio signals beamed to Earth. The 16 new objects are reported in this week’s edition of Science Express, in a study based out of the University of California in Santa Cruz.
A pulsar is a rapidly spinning neutron star, the dense core left behind after a supernova explosion. Most of the 1,800 known pulsars were found through their periodic radio emissions.
“These are the first pulsars ever detected by gamma rays alone, and already we’ve found 16,” said co-author Robert Johnson, a UC Santa Cruz physicist. “The existence of a large population of radio-quiet pulsars was suspected prior to this, but until Fermi was launched, only one radio-quiet pulsar was known, and it was first detected in x-rays.”
Of the 16 gamma-ray pulsars, 13 are associated with unidentified gamma-ray sources detected previously by the EGRET instrument on the Compton Gamma-ray Observatory. EGRET detected nearly 300 gamma-ray point sources, but was unable to detect pulsations from those sources, most of which have remained unidentified, said Pablo Saz Parkinson, also a SCIPP postdoctoral researcher and corresponding author of the paper.
“It’s been a longstanding question what could be powering those unidentified sources, and the new Fermi results tell us that a lot of them are pulsars,” Saz Parkinson said. “These findings are also giving us important clues about the mechanism of pulsar emissions.”
A pulsar emits narrow beams of radio waves from the magnetic poles of the neutron star, and the beams sweep around like a lighthouse beacon because the magnetic poles are not aligned with the star’s spin axis. If the radio beam misses the Earth, the pulsar cannot be detected by radio telescopes. Fermi’s ability to detect so many radio-quiet gamma-ray pulsars indicates that the gamma-rays are emitted in a beam that is wider and more fan-like than the radio beam.
The team identified the gamma-ray pulsars in data from Fermi’s Large Area Telescope (LAT). Marcus Ziegler, a postdoctoral researcher at UC Santa Cruz and corresponding author of the paper, said detection of gamma-ray pulsations from a typical source requires weeks or months of data from the LAT.
“From the faintest pulsar we studied, the LAT sees only two gamma-ray photons a day,” Ziegler said.
The very intense magnetic and electric fields of a pulsar accelerate charged particles to nearly the speed of light, and these particles are ultimately responsible for the gamma-ray emissions.
Because the rotation of the star powers the emissions, isolated pulsars slow down as they age and lose energy. But a binary companion star can feed material to a pulsar and spin it up to a rotation rate of 100 to 1,000 times a second. These are called millisecond pulsars, and Fermi scientists detected gamma-ray pulsations from eight millisecond pulsars that were previously discovered at radio wavelengths. Those results are reported in a second study also published in the July 2 edition of Science Express.
“Fermi has truly unprecedented power for discovering and studying gamma-ray pulsars,” said Paul Ray of the Naval Research Laboratory in Washington. “Since the demise of the Compton Gamma Ray Observatory a decade ago, we’ve wondered about the nature of unidentified gamma-ray sources it detected in our galaxy. These studies from Fermi lift the veil on many of them.”
Lead image caption: This all-sky map shows the positions of 16 new pulsars (yellow) and eight millisecond pulsars (magenta) studied using Fermi’s LAT. Credit: NASA/DOE/Fermi LAT Collaboration
Artists's Conception of M87's inner core: Black hole, accretion disk, and inner jets. Credit: Bill Saxton, NRAO/AUI/NSF
[/caption]
When the giant radio galaxy Messier 87 (M 87) unleashed a torrent of gamma radiation and radio flux, an international collaboration of 390 scientists happened to be watching. They’re reporting the discovery in this week’s issue of Science Express.
Large-scale VLA image of M87: White circle indicates the area within which the gamma-ray telescopes could tell the very energetic gamma rays were being emitted. To narrow down the location further required the VLBA. CREDIT: NRAO/AUI/NSF
The results give first experimental evidence that particles are accelerated to extremely high energies in the immediate vicinity of a supermassive black hole and then emit the observed gamma rays. The gamma rays have energies a trillion times higher than the energy of visible light.
Matthias Beilicke and Henric Krawczynski, both physicists at Washington University in St. Louis, coordinated the project using the Very Energetic Radiation Imaging Telescope Array System (VERITAS) collaboration. The effort involved three arrays of 12-meter (39-foot) to 17-meter (56-foot) telescopes, which detect very high-energy gamma rays, and the Very Long Baseline Array (VLBA) that detects radio waves with high spatial precision.
“We had scheduled gamma-ray observations of M 87 in a close cooperative effort with the three major gamma-ray observatories VERITAS, H.E.S.S. and MAGIC, and we were lucky that an extraordinary gamma-ray flare happened just when the source was observed with the VLBA and its impressive spatial resolving power,” Beilicke said.
“Only combining the high-resolution radio observations with the VHE gamma-ray observations allowed us to locate the site of the gamma-ray production,” added R. Craig Walker, a staff scientist at the National Radio Astronomy Observatory in Socorro, New Mexico.
Peering Deeper Into the Core of M87: At top left, a VLA image of the galaxy shows the radio-emitting jets at a scale of about 200,000 light-years. Subsequent zooms progress closer into the galaxy's core, where the supermassive black hole resides. In the artist's conception (background). the black hole illustrated at the center is about twice the size of our Solar System, a tiny fraction of the size of the galaxy, but holding some six billion times the mass of the Sun. Credit: Bill Saxton, NRAO/AUI/NSF
M 87 is located at a distance of 50 million light years from Earth in the Virgo cluster of galaxies. The black hole in the center of M 87 is six billion times more massive than the Sun.
The size of a non-rotating black hole is given by the Schwarzschild radius. Everything — matter or radiation — that comes within one Schwarzschild radius of the center of the black hole will be swallowed by it. The Schwarzschild radius of the supermassive black hole in M 87 is comparable to the radius of our Solar System.
In the case of some supermassive black holes — as in M 87 — matter orbiting and approaching the black hole powers highly relativistic outflows, called jets. The matter in the jets travels away from the black hole, escaping its deadly gravitational force. The jets are some of the largest objects in the Universe, and they can reach out many thousands of light years from the vicinity of the black hole into the intergalactic medium.
Very high-energy gamma-ray emission from M 87 was first discovered in 1998 with the HEGRA Cherenkov telescopes. “But even today, M 87 is one of only about 25 sources outside our galaxy known to emit [very high energy] gamma rays,” says Beilicke.
The new observations now show that the particle acceleration, and the subsequent emission of gamma rays, can happen in the very “inner jet,” less than about 100 Schwarzschild radii away from the black hole, which is an extremely narrow space as compared with the total extent of the jet or the galaxy.
In addition to VERITAS and the VLBA, the High Energy Stereoscopic System (H.E.S.S.) and the Major Atmospheric Gamma-Ray Imaging Cherenkov (MAGIC) gamma-ray observatories were involved in these observations.
Lead image caption: Artists’s Conception of M87’s inner core: Black hole, accretion disk, and inner jets. Credit: Bill Saxton, NRAO/AUI/NSF
Second image: Large-scale VLA image of M87: White circle indicates the area within which the gamma-ray telescopes could tell the very energetic gamma rays were being emitted. To narrow down the location further required the VLBA. CREDIT: NRAO/AUI/NSF
Collage: At top left, a VLA image of the galaxy shows the radio-emitting jets at a scale of about 200,000 light-years. Subsequent zooms progress closer into the galaxy’s core, where the supermassive black hole resides. In the artist’s conception (background). the black hole illustrated at the center is about twice the size of our Solar System, a tiny fraction of the size of the galaxy, but holding some six billion times the mass of the Sun. Credit: Bill Saxton, NRAO/AUI/NSF
HLX-1 in the periphery of the edge-on spiral galaxy ESO 243-49. Credit: Heidi Sagerud.
[/caption]
It’s the Goldilocks variety of black holes: not too big and not too small.
The new source HLX-1, the light blue object to the top left of the galactic bulge, is the ambassador for a new class of black holes, more than 500 times the mass of the Sun. It lies on the periphery of the edge-on spiral galaxy ESO 243-49, about 290 million light years from Earth.
The discovery, led by Sean Farrell at Britain’s University of Leicester, appears today in the journal Nature.
Until now, identified blackholes have been either super-massive (several million to several billion times the mass of the Sun) in the center of galaxies, or about the size of a typical star (between three and 20 solar masses).
The new discovery is the first solid evidence of a new class of medium-sized blackholes and was made using the European Space Agency’s XMM-Newton X-ray space telescope. At the time of the discovery, Farrell and his team were working at the Centre d’Etude Spatiale des Rayonnements in France.
A black hole is a remnant of a collapsed star with such a powerful gravitational field that it absorbs all the light that passes near it and reflects nothing.
“While it is widely accepted that stellar mass blackholes are created during the death throes of massive stars, it is still unknown how super-massive blackholes are formed,” Farrell said.
It had been long believed by astrophysicists that there might be a third, intermediate class of blackholes, with masses between a hundred and several hundred thousand times that of the Sun. However, such blackholes had not been reliably detected until now.
One theory suggests that super-massive blackholes may be formed by the merger of a number of intermediate mass blackholes, Farrell said.
“To ratify such a theory, however, you must first prove the existence of intermediate blackholes. This is the best detection to date of such long sought after intermediate mass blackholes. ”
Using XMM-Newton observations carried out in 2004 and 2008, the team showed that HLX-1 displayed a variation in its X-ray signature. This indicated that it must be a single object and not a group of many fainter sources. The huge radiance observed can only be explained if HLX-1 contains a black hole more than 500 times the mass of the Sun. The authors say that no other physical explanation can account for the data.
Lead image caption: Artist’s impression of HLX-1 in the periphery of the edge-on spiral galaxy ESO 243-49. Credit: Heidi Sagerud.
Want to know when to stop tweeting and look heavenward for a view of the International Space Station? Follow one more account, then.
Several websites carry information about the space station’s path through the sky, but until now there’s been no service to alert people when the station is near them.
Dutch journalists Govert Schilling and Jaap Meijers have built a Twitter page to let people know when to look up.
The international, manned space station ISS is so easy to see mainly because of its huge solar panels that reflect sunlight. Since the start in 1998 the space station has orbited the earth over 60,000 times.
A new series of exceptionally bright passes will start in Europe this week. Other continents too will see – weather permitting – many great passes, for instance on July 7 in the United States and July 10 in East Asia.
People using Twitter can now receive an alert when the ISS will be passing at the location in their Twitter profile. All they have to do is follow the Twitter account @twisst: www.twitter.com/twisst
Twisst may be the first service on Twitter that sends out such highly personalised information. Twisst sends an alert to every follower personally, wherever in the world that person may be. More technical details are available here. Click here for an example of what an alert looks like.
The rim of RCW 86. Credit: ESO/E. Helder & NASA/Chandra
[/caption]
Mmm, pretty … and a tad menacing, at least in its explosive past. This is RCW 86, part of a stellar remnant whose explosion was recorded in 185 AD. By studying the remnant in detail, a team of astronomers has been able to nail down the source of cosmic rays that bombard Earth.
During the Apollo flights 40 years ago, astronauts reported seeing odd flashes of light, visible even with their eyes closed. We have since learned that the cause was cosmic rays — extremely energetic particles from outside the Solar System arriving at the Earth, and constantly bombarding its atmosphere. Once they reach Earth, they still have enough energy to cause glitches in electronic components.
Galactic cosmic rays come from sources inside our home galaxy, the Milky Way, and consist mostly of protons moving at close to the speed of light, the “ultimate speed limit” in the Universe. These protons have been accelerated to energies exceeding by far the energies that even CERN’s Large Hadron Collider will be able to achieve.
“It has long been thought that the super-accelerators that produce these cosmic rays in the Milky Way are the expanding envelopes created by exploded stars, but our observations reveal the smoking gun that proves it,” says Eveline Helder from Utrecht University in the Netherlands, the first author of the new study in this week’s Science Express.
“You could even say that we have now confirmed the caliber of the gun used to accelerate cosmic rays to their tremendous energies,” adds collaborator Jacco Vink, also from the Astronomical Institute Utrecht.
For the first time Helder, Vink and colleagues have come up with a measurement that solves the long-standing astronomical quandary of whether or not stellar explosions produce enough accelerated particles to explain the number of cosmic rays that hit the Earth’s atmosphere. The team’s study indicates that they indeed do and directly tells us how much energy is removed from the shocked gas in the stellar explosion and used to accelerate particles.
“When a star explodes in what we call a supernova a large part of the explosion energy is used for accelerating some particles up to extremely high energies,” says Helder. “The energy that is used for particle acceleration is at the expense of heating the gas, which is therefore much colder than theory predicts.”
The researchers looked at the remnant of a star that exploded in AD 185, as recorded by Chinese astronomers. RCW 86, is located about 8,200 light-years away towards the constellation of Circinus (the Drawing Compass). It is probably the oldest record of the explosion of a star.
Using ESO’s Very Large Telescope, the team measured the temperature of the gas right behind the shock wave created by the stellar explosion. They measured the speed of the shock wave as well, using images taken with NASA’s X-ray Observatory Chandra three years apart. They found it to be moving AT between 1 and 3 percent the speed of light.
The temperature of the gas turned out to be 30 million degrees Celsius. This is quite hot compared to everyday standards, but much lower than expected, given the measured shock wave’s velocity. This should have heated the gas up to at least half a billion degrees.
“The missing energy is what drives the cosmic rays,” concludes Vink.
More about the lead image: North is toward the top right and east to the top left. The image is about 6 arc minutes across. Credit: ESO/E. Helder & NASA/Chandra
Image of Enceladus from Cassini. Credit: NASA/JPL/Space Science Institute
[/caption]
Two papers in the journal Nature this week come down on opposite sides of the question about whether Saturn’s moon Enceladus contains a salty, liquid ocean.
One research team, from Europe, says an enormous plume of water spurting in giant jets from the moon’s south pole is fed by a salty ocean. The other group, led out of the University of Colorado at Boulder, contends that the supposed geysers don’t have enough sodium to come from an ocean. The truth could have implications for the search for extraterrestrial life, as well as our understanding of how planetary moons are formed.
The Cassini spacecraft first spotted the plume on its exploration of the giant ringed planet in 2005. Enceladus ejects water vapor, gas and tiny grains of
ice into space hundreds of kilometers above the moon’s surface.
The moon, which orbits in Saturn’s outermost “E” ring, is one of only
three outer solar system bodies that produce active eruptions of dust
and vapor. Moreover, aside from the Earth, Mars, and Jupiter’s moon
Europa, it is one of the only places in the solar system for which
astronomers have direct evidence of the presence of water.
The European researchers, led by Frank Postberg of the University of Heidelberg in Germany, are reporting the detection of sodium salts among the dust ejected in the Enceladus plume. Postberg and colleagues have studied data from the Cosmic Dust Analyzer (CDA) onboard the Cassini
spacecraft and have combined the data with laboratory experiments.
They say the icy grains in the Enceladus plume contain
substantial quantities of sodium salts, hinting at the salty ocean
deep below.
The results of their study imply that the concentration of sodium chloride in the ocean can be as high as that of Earth’s oceans and is about 0.1-0.3 moles of salt per kilogram of water.
But the Colorado study suggests a different interpretation.
Nicholas Schneider, of CU-Boulder’s Laboratory for Atmospheric and Space Physics, and his colleagues say high amounts of sodium in the plume should give off the same yellow light that comes off street lights, and that the world’s best telescopes can detect even a small number of sodium atoms orbiting Saturn.
Schneider’s team usied the 10-meter Keck 1 telescope and the 4-meter Anglo-Australian telescope, and demonstrated that few if any sodium atoms existed in the water vapor. “It would have been very exciting to support the geyser hypothesis. But it is not what Mother Nature is telling us,” said Schneider.
One suggested explanation for the contrasting results, said Schneider, is that deep caverns may exist where water evaporates slowly. When the evaporation process is slow the vapor contains little sodium, just like water evaporating from the ocean. The vapor turns into a jet because it leaks out of small cracks in the crust into the vacuum of space.
“Only if the evaporation is more explosive would it contain more salt,” he said. “This idea of slow evaporation from a deep cavernous ocean is not the dramatic idea that we imagined before, but it is possible given both our results so far.”
But Schneider also cautions that several other explanations for the jets are equally plausible. “It could still be warm ice vaporizing away into space. It could even be places where the crust rubs against itself from tidal motions and the friction creates liquid water that would then evaporate into space,” he said.
“These are all hypotheses but we can’t verify any one with the results so far,” said Schneider. “We have to take them all with, well, a grain of salt.”
Lead photo caption: Image of Enceladus from Cassini. Credit: NASA/JPL/Space Science Institute
Credit: Left panel: X-ray (NASA/CXC/Durham Univ./D.Alexander et al.); Optical (NASA/ESA/STScI/IoA/S.Chapman et al.); Lyman-alpha Optical (NAOJ/Subaru/Tohoku Univ./T.Hayashino et al.); Infrared (NASA/JPL-Caltech/Durham Univ./J.Geach et al.); Right, Illustration: NASA/CXC/M.Weiss
[/caption]
Astronomers say they’ve discovered the “coming of age” of galaxies and black holes, thanks to new data from NASA’s Chandra X-ray Observatory and other telescopes. The new discovery helps resolve the true nature of gigantic blobs of gas observed around very young galaxies, and sheds light on the formation of galaxies and black holes.
The findings, led by Jim Geach of Durham University in the UK, will appear in the July 10 issue of The Astrophysical Journal.
About a decade ago, astronomers discovered immense reservoirs of hydrogen gas — which they named “blobs” – while conducting surveys of young distant galaxies. The blobs are glowing brightly in optical light, but the source of immense energy required to power this glow and the nature of these objects were unclear.
Based on the new data and theoretical arguments, Geach and his colleagues show that heating of gas by growing supermassive black holes and bursts of star formation, rather than cooling of gas, most likely powers the blobs. The implication is that blobs represent a stage when the galaxies and black holes are just starting to switch off their rapid growth because of these heating processes. This is a crucial stage of the evolution of galaxies and black holes – known as “feedback” – and one that astronomers have long been trying to understand.
“We’re seeing signs that the galaxies and black holes inside these blobs are coming of age and are now pushing back on the infalling gas to prevent further growth,” said coauthor Bret Lehmer, also of Durham. “Massive galaxies must go through a stage like this or they would form too many stars and so end up ridiculously large by the present day.”
Chandra and a collection of other telescopes including Spitzer have observed 29 blobs in one large field in the sky dubbed “SSA22.” These blobs, which are several hundred thousand light years across, are seen when the Universe is only about two billion years old, or roughly 15 percent of its current age.
In five of these blobs, the Chandra data revealed the telltale signature of growing supermassive black holes – a point-like source with luminous X-ray emission. These giant black holes are thought to reside at the centers of most galaxies today, including our own. Another three of the blobs in this field show possible evidence for such black holes. Based on further observations, including Spitzer data, the research team was able to determine that several of these galaxies are also dominated by remarkable levels of star formation.
The radiation and powerful outflows from these black holes and bursts of star formation are, according to calculations, powerful enough to light up the hydrogen gas in the blobs they inhabit. In the cases where the signatures of these black holes were not detected, the blobs are generally fainter. The authors show that black holes bright enough to power these blobs would be too dim to be detected given the length of the Chandra observations.
Besides explaining the power source of the blobs, these results help explain their future. Under the heating scenario, the gas in the blobs will not cool down to form stars but will add to the hot gas found between galaxies. SSA22 itself could evolve into a massive galaxy cluster.
“In the beginning the blobs would have fed their galaxies, but what we see now are more like leftovers,” said Geach. “This means we’ll have to look even further back in time to catch galaxies and black holes in the act of forming from blobs.”
Sources/more information: the Chandra sites at Harvard and NASA.
![Previous optical image of the Helix Nebula, demonstrating diffuse gas surrounding a central star. The white box shows the area observed by the Subaru Telescope. Credit: NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner [STScI], and T.A. Rector [NRAO]](https://www.universetoday.com/wp-content/uploads/2009/07/afig4.jpg "Previous optical image of the Helix Nebula, demonstrating diffuse gas surrounding a central star. The white box shows the area observed by the Subaru Telescope. Credit: NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner [STScI], and T.A. Rector [NRAO]")
