What are being described as the 'deepest infrared and optical data ever taken' provide a new picture of the early evolution of the universe. Researchers have observed hundreds of bright galaxies from the era around 900 million years after the Big Bang and compared this catalog with a deeper look 200 million years earlier in time. The result: Only one galaxy, using the strictest criteria, turned up in the earlier period, an indication of vast changes in those 200 million years. The work comes from Rychard Bouwens and Garth Illingworth (University of California - Santa Cruz), who used the Hubble Space Telescope to look at early galaxy formation in dark patches of sky like the Hubble Ultra Deep Field and the Great Observatories Origins Deep Survey fields. The mechanism at work in this period of galactic evolution seems obvious. Says Illingworth: "The bigger, more luminous galaxies just were not in place at 700 million years after the Big Bang. Yet 200 million years later there were many...

Cosmological shadows? Theory predicts that objects between us and the source of the cosmic microwave background should cast them. Specifically, the hot gases found in clusters of galaxies should show a measurable shadow effect produced by that background radiation, and there are reports of such effects from various observers. The scattering of the cosmic microwave background by high-energy electrons is known as the Sunyaev-Zel'dovich effect. However, a new study from the University of Alabama at Huntsville raises real problems. The first to study the phenomena with data from the Wilkinson Microwave Anisotropy Probe (WMAP), the team reports an oddly sporadic shadow effect for a background thought to be afterglow radiation from the Big Bang. And that raises questions about the Big Bang model itself. Says physicist Richard Lieu, after an investigation involving 31 clusters of galaxies: "These shadows are a well-known thing that has been predicted for years. This is the only direct...

A black hole two billion times more massive than the Sun is not something you find every day. Even more unusual is to find it embedded in a quasar that is 12.7 billion light years from Earth. But that's just what Tomotsugu Goto (Japan Aerospace Exploration Agency) seems to have found using the Subaru optical-infrared telescope on Mauna Kea. How a black hole of this mass could have formed only a billion years after the birth of the universe is only one of the questions this find poses. For the object, found in the direction of Cancer, also shows via its spectrum that much of the hydrogen between the quasar and Earth is ionized. What would cause neutral hydrogen to be converted to ionized hydrogen in this early epoch? Ultraviolet radiation is thought to be the key, but observational evidence helping us understand how and when this occurred has always been tricky to gather for a reionization event that occurred over 12 billion years ago. Quasars are useful beacons by which to study this...

Now and then it's good to step back from interstellar advocacy, especially on a weekend, and just look at the sky. To that end, the photograph below can be considered an object of contemplation, something to quiet the rush of the work week and return the mind to the far reaches. You're looking at a region within the Large Magellanic Cloud that contains hot blue stars, some of them brighter than a million Suns. That kind of energy pushes stellar 'winds' -- charged particles moving at tremendous speeds -- out into the surrounding interstellar gas. Image: This active region of star formation in the Large Magellanic Cloud (LMC), as photographed by NASA's Hubble Space Telescope, unveils wispy clouds of hydrogen and oxygen that swirl and mix with dust on a canvas of astronomical size. The LMC is a satellite galaxy of the Milky Way. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA). And look at those dust streamers running the length of the nebula, as well as the bright orange of...

We've just looked at the interesting work of Kris Stanek and collaborators on the Hubble constant, which could be taken to imply that previous measurements of this important figure are off by about 15 percent. Stanek's data point to a Hubble constant of 61 kilometers per second per megaparsec (a megaparsec is equal to 3.26 million light years); current estimates had begun to settle in comfortably at around 70 (km/s)/Mpc, although some astronomers, most conspicuously Allan Sandage, held out for a much lower figure. Now comes news of a study working with x-ray data from the Chandra space observatory and radio observations of galaxy clusters. Using this information, Max Bonamente (MSFC) and team have made distance measurements to 38 galaxy clusters ranging from 1.4 billion to 9.3 billion light years from Earth. Their finding on the Hubble constant pegs it at 77 kilometers per second per megaparsec, with an uncertainty of about 15%. And it's a finding more or less in agreement with...

It was in 1929 that Edwin Hubble formulated a key principle about the universe. Hubble realized that the redshift of distant galaxies was proportional to their distance, and refinements to the Hubble constant have brought some sense of order to our view of the expanding cosmos ever since. But an Ohio State astronomer and his colleagues now argue for tweaking Hubble, to the tune of 15 percent. That's the difference between previous readings of the distance to M33, the Triangulum Galaxy, and the value they have recently measured. The paper by Kris Stanek and co-authors is slated for the Astrophysical Journal, and is available in preprint form here. In it, the team describes its study of M33 in optical and infrared wavelengths using a wide variety of instruments including the 10-meter telescopes at Hawaii's Keck Observatory. The work on an eclipsing binary system in M33 produced a measurement of 3 million light years from Earth for the galaxy as opposed to the 2.6 million as determined...

The super-massive black holes thought to lurk in nearby galaxies present us with a problem. They should suck in surrounding gas and dust to produce x-rays, and it has been the assumption that black holes hidden by such materials, also known as 'Compton-thick objects,' are responsible for much of the overall x-ray background. Yet an x-ray census using data from Integral, ESA's orbiting International Gamma Ray Astrophysics Laboratory, showed that a mere 15 percent of black hole galaxies detected were of the hidden Compton-thick variety. And later work at NASA (GSFC) and the Integral Science Data Centre (Geneva), using two years of Integral data, shows an even smaller fraction. So where do the x-rays come from? "Naturally, it is difficult to find something we know is hiding well and which has eluded detection so far," says Volker Beckmann (NASA GSFC, and lead author of an upcoming paper on the subject). "Integral is a telescope that should see nearby hidden black holes, but we have come...

RS Ophiuchi, a binary system some 5000 light years from Earth, has given astronomers plenty to talk about since February, when it suddenly brightened. The phenomenon wasn't unusual -- RS Ophiuchi undergoes periodic outbursts -- but this was the first since 1985, allowing powerful radio telescope arrays to study the results. By coordination between radio telescopes from South Africa to China, Hawaii to the UK, astronomers have pieced together the sequence of events that led to the explosion and have studied its aftermath. The results are reported in the July 20 issue of Nature, revealing that a mere two weeks after first reports of the stellar eruption, an expanding blast wave extended to a distance of 10 AU. It was triggered by a nuclear explosion on the surface of a white dwarf that had been capturing gas from the nearby gas giant it orbits. Once enough gas collects on the white dwarf, a thermonuclear reaction begins, with the white dwarf's energy output increasing to over 100,000...

Supernova remnant RCW103 is not exactly a new discovery. In fact, it was found over 25 years ago, the survivor of an explosion that took place in the early days of the Roman empire, though visible only in southern skies. And as you would expect, the area in question looks to be fairly standard issue for a supernova aftermath: a rapidly spinning neutron star and a surrounding bubble of material ejected by the explosion. But look again, as an Italian team using the European Space Agency's XMM-Newton x-ray satellite has done, and you spot some anomalies. The scientists, based at the Istituto Nazionale di Astrofisica (INAF) in Milan, find that emissions from the central source of the explosion repeat on a cycle of 6.7 hours, far longer than would be expected from such a neutron star. Another oddity is that the spectral properties found in these observations differ from another set of data made just five years ago with the same XMM-Newton equipment. So what we have is an object embedded...

When I was growing up, 'blob' was a word associated with a classic horror movie starring none other than Steve McQueen. Today, blobs are starting to show up in astronomical discussions. Exactly what they are is unknown, but they seem to be as large as galaxies and marked by low luminosity. The latest, an apparently energetic but not very bright object some 11.6 billion light years away, is fully twice the size of our Milky Way and emits the energy of some two billion suns. It is, nonetheless, invisible in images from telescopes looking all the way from the infrared to the x-ray wavebands. How do you find invisible blobs? Astronomers working with the European Southern Observatory's Very Large Telescope used a narrow-band filter with the FORS1 spectrograph that allowed them to observe emissions from hydrogen atoms. Applying energy to hydrogen atoms causes their electrons to make a quantum leap to a higher energy level. Upon return to their initial state, the electrons release excess...

What exactly is the object recently discovered by the Hubble Space Telescope's Advanced Camera for Surveys in the constellation Boötes? If it's a supernova, it's an odd one, since it took five times longer (100 days) to reach peak brightness than a normal supernova. In fact, indications are it brightened by a factor of more than 200 since late January. As discussed in a June 19 New Scientist story, its spectrum is unusual, its color has not changed since the first observations came in, and it does not seem to be situated in a host galaxy. If distance measurements of 5.5 billion light years are accurate, it is also brighter than a Type 1A supernova should be at that distance. Then again, redshift uncertainties make the distance readings problematic. An unusual supernova at a far greater distance, perhaps as much as 12 billion light years? Nobody knows at this point. The object was flagged by the Supernova Cosmology Project headquartered at Lawrence Berkeley National Laboratory, an...

Einstein's theory of general relativity predicts the existence of gravitational waves, and if it's good enough for Einstein, it's good enough for LISA, the Laser Interferometer Space Antenna mission scheduled for launch in 2015. LISA will search the universe for gravitational waves, a coup if detected since they have until now remained in the domain of theory. And if the spacecraft finds its target, chances are it will be picking up gravitational waves from the collision of supermassive black holes that occur when galaxies merge. All of which is germane to new work by a team led by Stelios Kazantzidis (University of Chicago). Kazantzidis is working on galaxy collisions, simulating them to identify what leads to the mergers of such black holes. After all, if supermassive black hole collisions are numerous, the chances of LISA detecting their gravitational waves go up. The team is using supercomputers to simulate an intricate gravitational dance. Most stars in such galaxy collisions...

What exactly is the object astronomers have discovered 30,000 light years away in the constellation Cepheus? The Spitzer Space Telescope found it, but the source only shows up in mid-infrared images as a re-orange blob. Scan the same region of sky in visible light or near-infrared and you see absolutely nothing, and x-ray and radio views of the same region have never betrayed the object. A stealth supernova? Apparently so, in the eyes of Patrick Morris (California Institute of Technology), who is lead author of a paper on the discovery in the April Astrophysical Journal Letters. And it's a fascinating find, because the average supernova (if there is such a thing) makes itself known by lighting up surrounding areas of dust. The new object is far from the galaxy's most crowded and dusty regions, so the gas and radiation it would have spewed into space had little to interact with. Image (click to enlarge): Unlike most supernova remnants, which are detectable at a variety of wavelengths...

How do you get two supermassive black holes in each other's neighborhood? That's the question raised by the discovery of a pair of such objects, each 150 million times more massive than the Sun, and separated by a cosmically minute 24 light years. They're in the center of a galaxy called 0402+379, some 750 million light years from Earth, and they orbit each other every 150,000 years. "Astronomers have thought for a long time that close pairs of black holes should result from galaxy collisions," says Cristina Rodriguez (University of New Mexico and Simon Bolivar University in Venezuela). And that's apparently what happened here. Astronomers working with the Very Long Baseline Array (VLBA) radio telescope think that these black holes were each at the core of separate galaxies. A collision between the galaxies would then have left the two objects orbiting each other. It would be intriguing indeed if the black holes themselves would collide, as the event should cause strong gravitational...