The galaxy HFLS3 appears as a small red dot in these Herschel submillimeter images (main image, and panels on right). Subsequent observations with ground-based telescopes, ranging from optical to millimeter wavelengths (insets), revealed two galaxies appearing very close together. The two are actually at very different distances, however, and HFLS3 (blue, in millimeter wavelengths) is so far away that we are seeing it as it was when the universe was just 880 million years old. Credit: ESA/Herschel/HerMES/IRAM/GTC/W.M. Keck Observatory.
Most of the early galaxies that astronomers have been able to observe are small with a low-to-moderate amount of star production. But now the Herschel Space Observatory has found a massive dust-filled galaxy churning out stars at an incredible rate, with all of this taking place back when the cosmos was a just 880 million years old. The galaxy is about as massive as our Milky Way, but produces stars at a rate 2,000 times greater, prompting the researchers to call it a “maximum-starburst” galaxy.
The astronomers involved in its discovery say its mere existence challenges our theories of galaxy evolution.
“Massive, intense starburst galaxies are expected to only appear at later cosmic times,” says Dominik Riechers, currently an assistant professor at Cornell. “Yet, we have discovered this colossal starburst just 880 million years after the Big Bang, when the universe was at little more than 6 percent of its current age. Riechers is the first author of the paper describing the findings in the April 18 issue of the journal Nature.
The prevailing thought on early galaxy and star formation has been that the first galaxies to form were relatively small and lightweight, containing only a few billion times the mass of our Sun. They form their first stars at rates of a few times that experienced by the Milky Way today, and the galaxies would grow by merging with other small galaxies. In theory, galaxies as massive as the newly found galaxy – named HFLS3 — should not be present so soon after the Big Bang.
HFLS3 appears as little more than a faint, red smudge in images from the Herschel Multi-tiered Extragalactic Survey (HerMES).
The extreme distance to HFLS3 means that its light has travelled for almost 13 billion years across space before reaching us. We therefore see it as it existed in the infant Universe, just 880 million years after the Big Bang or at 6.5% of the Universe’s current age.
This artist’s impression shows the “starburst” galaxy HFLS3. The galaxy appears as little more than a faint, red smudge in images from the Herschel space observatory. Image credit: ESA-C. Carreau.
Even at that young age, HFLS3 was already close to the mass of the Milky Way, with roughly 140 billion times the mass of the Sun in the form of stars and star-forming material. After another 13 billion years, it should have grown to be as big as the most massive galaxies known in the local Universe.
“Looking for the first examples of these massive star factories is like searching for a needle in a haystack; the Herschel dataset is extremely rich,” said Riechers.
Tens of thousands of massive, star-forming galaxies have been detected by Herschel as part of HerMES and sifting through them to find the most interesting ones is a challenge.
“This particular galaxy got our attention because it was bright, and yet very red compared to others like it,” said co-investigator Dave Clements of Imperial College London.
While the discovery of this single galaxy isn’t enough to overturn current theories of galaxy formation, finding more galaxies like this one could challenge those theories, the astronomers say. At the very least, theories will have to be modified to explain how this galaxy formed, Riechers says.
“This galaxy is just one spectacular example, but it’s telling us that extremely vigorous star formation was possible early in the universe,” says Jamie Bock, professor of physics at Caltech and a coauthor of the paper.
The original Apollo 13 crew, from left to right: Jim Lovell, Thomas "Ken" Mattingly, Fred Haise. Credit: NASA
Many astronauts seem to like the Apollo 13 movie, but being technically minded folk they also enjoy pointing out what actually happened during that so-called “successful failure” that landed safely on this day in 1970.
Thomas “Ken” Mattingly was supposed to be on that crew, but was yanked at the last minute because he was exposed to the German measles. The movie shows him wallowing on the couch with a can of beer before hearing of an oxygen tank explosion on board. He then spends most of the movie stuck in a simulator, helping to save the three men on board the spacecraft.
Real life wasn’t quite the same as the movie portrayed, the real Mattingly said in a 2001 interview with NASA.
For one thing, Mattingly had no assigned role in the rescue as he was a backup crew member. He ended up working in a lot of teams rather than a single project or two. There also were some technical differences between the movie and real life. Some examples:
The “lifeboat” procedures: In the movie, mission controllers huddle in a side room and try to figure out how to stretch the resources of the lunar module — designed to carry only two men for a couple of days — into a four-day lifeboat to support three men. While this is somewhat true, NASA already had a preliminary lifeboat procedure simulated, Mattingly pointed out. The movie made it appear as though, he said, “we invented a lot of stuff”.
Somewhere in an earlier sim [simulation], there had been an occasion to do what they call LM lifeboat, which meant you had to get the crew out of the command module and into the lunar module, and they stayed there. I vaguely remember—when you have a really exciting sim, why, generally everybody knows about it. I vaguely remember that they had come up with a thing that contaminated the atmosphere in the command module, and they had to vent it, and they put the crew into the—there’s some reason that instead of staying in their suits in the command module, they put them in the lunar module while they did this.
Apollo 13’s original crew of Jim Lovell, Ken Mattingly and Fred Haise with an unidentified person. Credit: NASA
The carbon dioxide filter: In the movie, as the crew faces a deadly buildup of carbon dioxide, a team in mission control builds a new system on the spot that adapts an originally incompatible filter. “Well, the real world is better than that,” Mattingly explained, saying there was a simulation for the Apollo 8 mission where a cabin fan was jammed due to a loose screw.
The solution that they came up with was that they could make a way to use the vacuum cleaner in the command module with some plastic bags cut up and taped to the lithium hydroxide cartridges and blow through it with a vacuum cleaner. So, having discovered it, they said, “Okay, it’s time for beer.” Well, on 13, someone says, “You remember what we did on that sim? Who did that?” So in nothing short, Joe [Joseph P.] Kerwin showed up, and we talked about “How did you build that bag and what did you do?” … Of course it worked like a gem.
Simulating the startup: In the movie, Mattingly spends hours in a simulator putting together the procedures for starting up the cold, dead command module in time to bring the astronauts safely back to Earth. While that is a good way of conveying the mission’s aim to the public, the simulation runs (done by other astronauts, Mattingly said) were more of a verification of already written procedures.
We said, “Let’s get somebody cold to go run the procedures.” So I think it was [Thomas P.] Stafford, [Joe H.] Engle — I don’t know who was the third person, might have been [Stuart A.] Roosa. But anyhow, they went to the simulator there at JSC [Johnson Space Center], and we handed them these big written procedures and said, “Here. We’re going to call these out to you, and we want you to go through, just like Jack will. We’ll read it up to you. See if there are nomenclatures that we have made confusing or whatever. Just wring it out. See if there’s anything in the process that doesn’t work.”
For more on what Mattingly thinks of the Apollo 13 movie, check out the entire transcript of his interview on NASA’s website. We’re sure there are other technical details the movie simplified or got wrong, so feel free to share your thoughts in the comments.
Lyrid meteors will appear to radiate (red circle) from a point near the bright star Vega in the constellation Lyra. This map shows the sky facing southeast around 3:30 a.m. April 22 - around the time of maximum. Stellarium
Feeling a little meteor-starved lately? Me too. It’s been a meteor shower desert since the Quadrantids of early January. That’s about to change. This weekend brings the celestial version of April showers with the annual appearance of the Lyrids.
The Lyrids ding the bell at maximum strength this weekend April 21-22 (Sunday night-Monday morning in the Americas) hurtling meteors at the modest rate of 10-20 per hour from a point in the sky not far from bright Vega in the constellation Lyra. While some showers spread their meteor crumbs over several days, the Lyrids’ peak activity lasts less than a day. The western hemisphere – particularly the western half of North America – is favored this year.
A Lyrid meteor captured by NASA astronaut Don Pettit out the window of the International Space Station on April 21, 2012. The lights of Florida are visible to the right of the meteor. Click to enlarge. Credit: NASA
There will be a small price to pay for the show. The Lyrid radiant, the point in the sky from which the showers members radiate, rises in the east rather late – around 10:30 p.m. local time. Then there’s the bright gibbous moon, which has a habit of drowning out fainter stars and meteors alike. That makes the best time for viewing the shower after moonset or around 4 a.m. Monday morning. Since dawn begins about 5, you’ll have one good hour. That’s plenty of time to snag at least a few flaming motes of Comet Thatcher.
A bright fireball meteor in twilight. The Lyrids, like all meteor showers, offer up the occasional fireball among a mix of fainter meteors. Credit: John Chumack
Like most meteor showers, the Lyrids have a parent and single parents are the rule. For the Lyrids, it’s Comet Thatcher, discovered on April 5, 1861, a week before the start of the Civil War, by amateur astronomer A.E. Thatcher observing from New York City. Later it was found to be linked to the Lyrid meteor shower.
Each year in late April, Earth passes through centuries of dust shed by the comet’s tail. When bits of Thatcher flotsam strike the air some 60-70 miles high, they burn up in flashes of meteoric light. Comet tears.
The delicate, rarefied dust tail of Comer C/2012 K5 in Dec. 2012. If Earth happens to intersects a comet’s dusty orbit – as we do with Comet Thatcher every April – we witness a meteor shower. Credit: Michael Jaeger
All meteors are worthy of keeping an eye on, but bear in mind that the Lyrids are no Perseids, the famed summertime shower offering up to 60 meteors per hour under dark skies. But what they lack in numbers, they make up in reliability and surprise.
Records indicate that people have been watching the Lyrids for at least 2,600 years, the longest of any shower. Our oldest descriptions come from the Chinese who penned that “stars fell like rain” on March 16, 687 BC. Apparently the shower was more active in the past and has since evolved into a minor display. But there have been occasional surprises, and that’s what keeps the Lyrids interesting.
Comet Thatcher circles the sun once every approxiimately 415 years. Each time it does, the comet leaves dust and small bits of ice and rock in a trail behind it. Sometimes it sheds more dust than others, creating denser filaments that can make for unexpectedly high numbers of Lyrid meteors when the Earth passes through. Not to scale. Illustration: Bob King
On April 20, 1803 a fire bell roused Richmond, Virginia residents from their beds to witness a similar rain of stars when up to 700 meteors per hour were seen. Other Lyrid outbursts occurred in 1922 (100 per hour), 1945 (100/hr), 1982 (90/hour). Last year’s peak hit 37 per hour from a dark sky site. Now and then, Earth encounters a thicker band of comet debris left behind by Comet Thatcher, suddenly increasing the meteor count by many times and just as suddenly dropping back to the usual 10-20 per hour.
So here’s the bottom line. Don’t expect a big blast, but do avail yourself of the leisurely pleasure of meteor watching and the possibility of seeing pieces of a comet that rounds the sun only every 415 years. Find a spot where artificial lights is at a minimum, dress warmly and head out around 3:30 a.m. Monday. Set up a comfortable lawn chair and have tea or coffee and a blanket at the ready. You’ll do well to face south or east. Now recline back to allow a fulsome view of the sky above and wait for a few well-deserved ooohs and aaahs.
The orbital path of the International Space Station appears to take it through the Moon, as seen from the UK on April 16, 2013. Credit and copyright: Dave Walker.
What a great image! Astrophotographer Dave Walker combined seven 30-second shots of the ISS as it cuts through the sky, and it appears to slice right through the Moon! Dave used a a Canon 600D, Samyang 8mm fish-eye lens, and Vixen Polarie.
Now through the end of April provides some great sighting opportunities in the northern hemisphere for seeing the International Space Station as it flies overhead — and over your backyard! Some evenings there are even two passes. See below for another great panorama of an ISS pass, as well as information on how to find out when you can see it. It’s always an amazing sight!
A view of the International Space Station over St. Pölten, Austria on April 15, 2013. A panorama of 13 single shots, each with 25 sec. exposure-time. Credit and copyright: Ma Brau via Flickr.
NASA has a Skywatch page where you can find your specific city to look for satellite sighting info.
Spaceweather.com, has a Satellite Tracker Tool. Just put in your zip code (good for the US and Canada) to find out what satellites will be flying over your house.
Heaven’s Above also has a city search, but also you can input your exact latitude and longitude for exact sighting information, helpful if you live out in the country.
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
1st fully integrated Antares rocket stands firmly erect at seaside Launch Pad 0-A at NASA’s Wallops Flight Facility on 16 April 2013. Maiden Antares test launch is scheduled for 17 April 2013. Later operational flights are critical to resupply the ISS. Credit: Ken Kremer (kenkremer.com)
UPDATE: Wednesday’s test launch for Orbital Science Corporation’s Antares rocket was aborted due to the premature disconnection of a second-stage umbilical about 12 minutes before launch was scheduled. The earliest the flight can be rescheduled is Friday, April 19.
“We are still examining all of the data, but it appears that the issue is fairly straightforward,” said Frank Culbertson, Orbital’s executive vice president and mission director for the Antares test flight, in a statement released by the company. “With this being the first launch of the new system from a new launch facility we have taken prudent steps to ensure a safe and successful outcome. Today, our scrub procedures were exercised and worked as planned. We are looking forward to a successful launch on Friday.”
[end of update]
It’s been billed as “the biggest, loudest and brightest rocket ever to launch from NASA’s Wallops Flight Facility” in Virginia, and the commercial company Orbital Sciences Corporation is ready to send their Antares rocket on its maiden test flight. Orbital is testing Antares under NASA’s Commercial Orbital Transportation Services (COTS) program, and the rocket will send a dummy module into orbit that has the same mass as Orbital’s Cygnus cargo spacecraft, as well as a few smaller satellites, testing the rocket’s capabilities.
You can watch live here via NASA TV’s Ustream. There is a press briefing at 2 pm EDT (18:00 UTC), and launch coverage starts at 4:00 pm EDT (20:00 UTC), with the launch window open between 5 and 8 pm EDT (21:00 and midnight UTC).
This will mark not only the first launch of Antares, but the first orbital launch of a liquid-fueled rocket from Wallops. If all goes well with this flight, Orbital will carry out a full flight demonstration of Antares and the Cygnus cargo delivery system to the International Space Station around mid-2013.
Dr. Sally Ride, the first American woman to fly in space
Dr. Sally K. Ride, physicist, NASA astronaut, and first American woman to fly in space, will be honored with a U.S. Navy research vessel bearing her name, which will be operated by and homeported at San Diego’s Scripps Institution of Oceanography.
“Dr. Sally Ride inspired millions of people, especially young women and girls, to reach for the stars,” said U.S. Sen. Barbara Boxer, D-Calif. “Naming the Navy’s new ocean research vessel in her honor is a fitting tribute to her legacy of innovation and discovery.”
Dr. Ride died at her home in La Jolla on July 23, 2012, after a 17-month battle with pancreatic cancer. She was 61.
Sally Ride was a NASA astronaut for 11 years before joining the UCSD faculty as a physics professor and director of the California Space Institute.
Dr. Ride was selected for NASA’s astronaut corps in 1978 and became the first American woman in space aboard Space Shuttle Challenger in 1983. In 1989, she joined the faculty of UC San Diego as professor of physics and was director of the university’s California Space Institute.
“We are touched by the extraordinary honor that this ship is being named for Sally Ride, who, after serving our nation as a pioneering and accomplished astronaut, served on the faculty of UC San Diego for nearly two decades,” said UC San Diego Chancellor Pradeep K. Khosla in a Scripps press release. “Her commitment to teaching and inspiring young minds is legendary and we take tremendous pride in this prestigious and well-deserved honor for her legacy and for UC San Diego.”
According to Gary Robbins in an article for the San Diego Union-Tribune “It is common for a research vessel to be named after an explorer or scientist. Scripps’ current fleet of Navy-owned ships includes the Roger Revelle, which bears the name of the late UC San Diego scientist who helped pioneer the study of global warming. The Woods Hole Oceanographic Institution in Cape Cod, Mass. is getting a ship named R/V Neil Armstrong.”
Rendering of the R/V Sally Ride
Designed to operate globally, R/V Sally Ride will continue the Scripps legacy of conducting pioneering ocean exploration and research critical to our understanding of our planet, our oceans, and our atmosphere. As a shared-use, general-purpose ship, R/V Sally Ride will engage in a broad spectrum of research in physics, chemistry, biology, geology, and climate science, including research missions with relevance to the Navy.
As a seagoing laboratory supporting research and education, the new ship will feature modern research instrumentation to fuel scientific exploration, including mapping systems, sensors, and profilers that will investigate features from the seafloor to the atmosphere.
“I can’t think of a more perfect name for the Navy’s new research vessel. Dr. Ride was a trailblazer in every sense of the word in the fields of science and engineering. Dr. Ride’s namesake ship and its crew will continue her legacy of courage, determination, and spirit of discovery.”
– U.S. Rep. Susan Davis, D-Calif.
R/V Sally Ride is currently under construction at Dakota Creek Industries Inc. in Anacortes, Washington, and is scheduled for launch in 2015.
Antares rocket erect at the Eastern shore of Virginia slated for maiden liftoff on April 17. Only a few hundred feet of beach sand and a miniscule sea wall separate the Wallops Island pad from the Atlantic Ocean waves and Mother Nature. Credit: Ken Kremer (kenkremer.com)
The commercial space competition race is about to begin, and with a big bang at a most unexpected locale; Virginia’s Eastern shore.
The new and privately developed Antares rocket will ignite a new space race in the commercial arena – if all goes well – when the engines fire for Antares maiden soar to space slated for Wednesday, April 17.
“This is the biggest, loudest and brightest rocket ever to launch from NASA’s Wallops Flight Facility,” said former station astronaut and now Orbital Sciences manager Frank Culbertson, at a media briefing held today (April 16), 1 day prior to liftoff.
The April 17 launch is a test flight of the Antares rocket, built by Orbital Sciences Corp and is due to liftoff at 5 p.m. EDT from Mid-Atlantic Regional Spaceport (MARS) Pad-0A at NASA Wallops.
The weather forecast shows a 45% chance of favorable weather.
The mission is dubbed the A-One Test Launch Mission.
The launch will be visible along portions of the US East Coast from South Carolina to Maine, depending on viewing conditions.
Antares is the most powerful rocket ever to ascend near major American East Coast population centers, unlike anything before – and critical to keeping the ISS fully functioning.
For the past year, SpaceX Corp founded by CEO Elon Musk has monopolized all the commercial space headlines – as the first and only private company to launch a spacecraft that successfully docked at the International Space Station (ISS).
1st fully integrated Antares rocket stands firmly erect at seaside Launch Pad 0-A at NASA’s Wallops Flight Facility on 16 April 2013. Maiden Antares test launch is scheduled for 17 April 2013. Later operational flights are critical to resupply the ISS. Credit: Ken Kremer (kenkremer.com)
Indeed SpaceX just concluded its 3rd flight to the ISS lofting thousands of pounds (kg) of critically needed supplies to the ISS to keep it functioning – and numerous science experiments to keep the 6 person crew of astronauts busy conducting over 200 active science investigations and fulfill the stations purpose.
Orbital Sciences aims to match and perhaps even exceed the SpaceX Falcon 9 /Dragon architecture with its own ambitious space station resupply system comprising the medium class Antares rocket and Cygnus cargo resupply vehicle.
“The Cygnus can remain docked to the ISS for 30 to 90 days,” said former station astronaut and now Orbital Sciences manager Frank Culbertson at the briefing.
“Cygnus could be upgraded to stay longer perhaps up to a year in orbit,” Culbertson told Universe Today.
“Cygnus is based on the proven MPLM design. It could possibly be converted to a permanent habitation module for the ISS with added shielding and plumbing, if funding is available and if NASA wants to pursue that possibility,” Culbertson told me.
“This is a big event for this area and our country,” said Culbertson.
During the test flight Antares will boost a simulated Cygnus – known as a mass simulator – into a target orbit of 250 x 300 kilometers and inclined 51.6 degrees.
Antares rocket configuration – privately developed by Orbital Sciences Corp.
The Antares first stage is powered by dual liquid fueled AJ26 first stage rocket engines that generate a combined total thrust of some 750,000 lbs. The upper stage features a Castor 30 solid rocket motor with thrust vectoring. Antares can loft payloads weighing over 5000 kg to LEO.
Dozens of technicians were working at the pad during my photoshoot today.
The Antares/Cygnus system was developed by Orbital Sciences Corp under NASA’s Commercial Orbital Transportation Services (COTS) program to replace the ISS cargo resupply capability previously tasked to NASA’s now retired Space Shuttle fleet.
Over the next 3 to 4 years, eight Cygnus carriers will loft 20,000 kg of supplies, food, water, clothing , replacement parts and science gear to the ISS under a NASA contract valued at $1.9 Billion.
“This represents a new way of doing business for NASA,” said NASA’s commercial crew program manager Alan Lindenmoyer.
NASA Wallops Director Jay Wrobel has granted the formal Authority to Proceed for Orbital Science Corporation’s test launch of its Antares rocket.
Following today’s Flight Readiness review, Orbital managers gave a “GO” to proceed toward launch.
NASA TV launch coverage begins at 4 p.m. EDT on April 17.
Watch for my continuing on-site reports through liftoff of the Antares A-One Test flight.
Learn more about Orion, Antares, SpaceX, Curiosity and NASA robotic and human spaceflight missions at Ken’s upcoming lecture presentations:
April 20/21 : “Curiosity and the Search for Life on Mars – (in 3-D)”. Plus “The Space Shuttle Finale and the Future of NASA – Orion, SpaceX, Antares and more!” NEAF Astronomy Forum, Rockland Community College, Suffern, NY. 3-4 PM Sat & Sunday. Display table all day.
April 28: “Curiosity and the Search for Life on Mars – (in 3-D)”. Plus the Space Shuttle, SpaceX, Antares, Orion and more. Washington Crossing State Park, Titusville, NJ, 130 PM
GRB 111209A exploded on Dec. 9, 2011. The blast produced high-energy emission for an astonishing seven hours, earning a record as the longest-duration GRB ever observed. This false-color image shows the event as captured by the X-ray Telescope aboard NASA's Swift satellite. Credit: NASA/Swift/B. Gendre (ASDC/INAF-OAR/ARTEMIS)
According to astronomer Andrew Levan, there’s an old adage in studying gamma ray bursts: “When you’ve seen one gamma ray burst, you’ve seen … only one gamma ray burst. They aren’t all the same,” he said during a press briefing on April 16 discussing the discovery of a very different kind of GRB – a type that comes in a new long-lasting flavor.
Three of these unusual long-lasting stellar explosions have recently been discovered using the Swift satellite and other international telescopes, and one, named GRB 111209A, is the longest GRB ever observed, with a duration of at least 25,000 seconds, or about 7 hours.
“We have observed the longest gamma ray burst in modern history, and think this event is caused by the death of a blue supergiant,” said Bruce Gendre, a researcher now associated with the French National Center for Scientific Research who led this study while at the Italian Space Agency’s Science Data Center in Frascati, Italy. “It caused the most powerful stellar explosion in recent history, and likely since the Big Bang occurred.”
The astronomers said these three GRBs represent a previously unrecognized class of these stellar explosions, which arise from the catastrophic deaths of supergiant stars hundreds of times larger than our Sun. GRBs are the most luminous and mysterious explosions in the Universe. The blasts emit surges of gamma rays — the most powerful form of light — as well as X-rays, and they produce afterglows that can be observed at optical and radio energies.
Swift, the Fermi telescope and other spacecraft detect an average of about one GRB each day. As to why this type of GRB hasn’t been detected before, Levan explained this new type appears to be difficult to find because of how long they last.
“Gamma ray telescopes usually detect a quick spike, and you look for a burst — at how many gamma rays come from the sky,” Levan told Universe Today. “But these new GRBs put out energy over a long period of time, over 10,000 seconds instead of the usual 100 seconds. Because it is spread out, it is harder to spot, and only since Swift launched do we have the ability to build up images of GBSs across the sky. To detect this new kind, you have to add up all the light over a long period of time.”
Levan is an astronomer at the University of Warwick in Coventry, England.
He added that these long-lasting GRBs were likely more common in the Universe’s past.
The number, duration and burst class for GRBs observed by Swift are shown in this plot. Colors link each GRB class to illustrations above the plot, which show the estimated sizes of the source stars. For comparison, the width of the yellow circle represents a star about 20 percent larger than the sun. Credit: Andrew Levan, Univ. of Warwick.
Traditionally, astronomers have recognized two types of GRBs: short and long, based on the duration of the gamma-ray signal. Short bursts last two seconds or less and are thought to represent a merger of compact objects in a binary system, with the most likely suspects being neutron stars and black holes. Long GRBs may last anywhere from several seconds to several minutes, with typical durations falling between 20 and 50 seconds. These events are thought to be associated with the collapse of a star many times the Sun’s mass and the resulting birth of a new black hole.
“It’s a very random process and every GRB looks very different,” said Levan during the briefing. “They all have a range of durations and a range of energies. It will take much bigger sample to see if this new type have more complexities than regular gamma rays bursts.”
All GRBs give rise to powerful jets that propel matter at nearly the speed of light in opposite directions. As they interact with matter in and around the star, the jets produce a spike of high-energy light.
Gendre and his colleagues made a detailed study of GRB 111209A, which erupted on Dec. 9, 2011, using gamma-ray data from the Konus instrument on NASA’s Wind spacecraft, X-ray observations from Swift and the European Space Agency’s XMM-Newton satellite, and optical data from the TAROT robotic observatory in La Silla, Chile. The 7-hour burst is by far the longest-duration GRB ever recorded.
Another event, GRB 101225A, exploded on December 25, 2010 and produced high-energy emission for at least two hours. Subsequently nicknamed the “Christmas burst,” the event’s distance was unknown, which led two teams to arrive at radically different physical interpretations. One group concluded the blast was caused by an asteroid or comet falling onto a neutron star within our own galaxy. Another team determined that the burst was the outcome of a merger event in an exotic binary system located some 3.5 billion light-years away.
“We now know that the Christmas burst occurred much farther off, more than halfway across the observable universe, and was consequently far more powerful than these researchers imagined,” said Levan.
Using the Gemini North Telescope in Hawaii, Levan and his team obtained a spectrum of the faint galaxy that hosted the Christmas burst. This enabled the scientists to identify emission lines of oxygen and hydrogen and determine how much these lines were displaced to lower energies compared to their appearance in a laboratory. This difference, known to astronomers as a redshift, places the burst some 7 billion light-years away.
Levan’s team also examined 111209A and the more recent burst 121027A, which exploded on Oct. 27, 2012. All show similar X-ray, ultraviolet and optical emission and all arose from the central regions of compact galaxies that were actively forming stars. The astronomers have concluded that all three GRBs constitute a new kind of GRB, which they are calling “ultra-long” bursts.
Astronomers suggest that blue supergiant stars may be the most likely sources of ultra-long GRBs. These stars hold about 20 times the sun’s mass and may reach sizes 1,000 times larger than the sun, making them nearly wide enough to span Jupiter’s orbit. Credit: NASA’s Goddard Space Flight Center/S. Wiessinger.
“Ultra-long GRBs arise from very large stars,” said Levan, “perhaps as big as the orbit of Jupiter. Because the material falling onto the black hole from the edge of the star has further to fall it takes longer to get there. Because it takes longer to get there, it powers the jet for a longer time, giving it time to break out of the star.”
Levan said that Wolf-Rayet stars best fit the description. “They are born with more than 25 times the Sun’s mass, but they burn so hot that they drive away their deep, outermost layer of hydrogen as an outflow we call a stellar wind,” he said. Stripping away the star’s atmosphere leaves an object massive enough to form a black hole but small enough for the particle jets to drill all the way through in times typical of long GRBs
John Graham and Andrew Fruchter, both astronomers at the Space Telescope Science Institute in Baltimore, provided details that these blue supergiant contain relatively modest amounts of elements heavier than helium, which astronomers call metals. This fits an apparent puzzle piece, that these ultra-long GRBs seem to have a strong intrinsic preference for low metallicity environments that contain just trace amounts of elements other than hydrogen and helium.
“High metalicity long duration GRBs do exist but are rare,” said Graham. “They occur at about 1/25th the rate (per unit of star formation) of the low metallicity events. This is good news for us here on Earth, as the likelihood of this type of GRB going off in our own galaxy is far less than previously thought.”
The astronomers discussed their findings Tuesday at the 2013 Huntsville Gamma-ray Burst Symposium in Nashville, Tenn., a meeting sponsored in part by the University of Alabama at Huntsville and NASA’s Swift and Fermi Gamma-ray Space Telescope missions. Gendre’s findings appear in the March 20 edition of The Astrophysical Journal.
This year, there have been some epic auroral displays, and astrophotographer Ole C. Salomonsen has just released this new video which includes real-time recordings of these “polar spirits.”
“My main focus is on getting the auroras [to] show as close as possible to real-time speed given the time available in a short video,” Salomonsen wrote on Vimeo. “In the film I have tried to show the slower majestic dancing lights, as well as the more faster, dramatic and abstract shows, and finally the auroras in combination with city lights and urban elements.”
Simply stunning, and if you watch closely on the opening sequence you can actually see some whales breaching out in the fjord!
Ancient iron-loving bacteria may have collected particles from a supernova that exploded about 2.2 million years ago. The Crab Nebula, shown here in this image from NASA's Hubble Space Telescope, is much younger having exploded in 1054. Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)
Ancient iron-loving bacteria may have scooped up evidence of a nearby supernova explosion 2.2 million years ago, leaving an extraterrestrial iron signature in the fossil record, according to German researchers presenting their findings at a recent meeting of the American Physical Society.
In 2004, German scientists reported finding an isotope of iron in a core sample from the Pacific Ocean that does not form on Earth. The scientists calculated the decay rate of the radioactive isotope iron-60 and determined that the source was from a nearby supernova about 2 million years ago. The blast, they say, was close enough to Earth to seriously damage the ozone layer and may have contributed to a marine extinction at the Pliocene-Pleistocene geologic boundary.
Shawn Bishop, a physicist with the Technical University of Munich in Germany and the primary author of the recent study, wondered if traces of the supernova could be found in the fossil record as well. Some deep sea bacteria soak up iron creating tiny magnetic crystals. These 100-nanometer-wide crystals form long chains inside highly-specialized organelles called magnetosomes which help the bacteria orient themselves to Earth’s magnetic field. Using a core sample from the eastern equatorial Pacific Ocean, Bishop and his team sampled strata spaced about 100,000 years apart. By using a chemical treatment that extracts iron-60 while leaving other iron, the scientists then ran the sample through a mass spectrometer to determine whether iron-60 was present.
And in the layers around 2.2 million years ago, tiny traces of iron-60 appeared.
Although the scientists are not sure which star exploded to rain radioactive iron onto Earth, the scientists refer to a paper from 2002 that points to several supernovae generated in the Scorpius-Centaurus star association. The group of young stars, just 130 parsecs (about 424 light-years) from Earth, has produced 20 supernovae within the past 11 million years.
