Posts tagged UV
CU study: ‘Sideline quasars’ helped to stifle early galaxy formation
Mar 21st
CU-Boulder Professor Michael Shull and Research Associate David Syphers used the Hubble Space Telescope to look at the quasar — the brilliant core of an active galaxy that acted as a “lighthouse” for the observations — to better understand the conditions of the early universe. The scientists studied gaseous material between the telescope and the quasar with a $70 million ultraviolet spectrograph on Hubble designed by a team from CU-Boulder’s Center for Astrophysics and Space Astronomy.
During a time known as the “helium reionization era” some 11 billion years ago, blasts of ionizing radiation from black holes believed to be seated in the cores of quasars stripped electrons from primeval helium atoms, said Shull. The initial ionization that charged up the helium gas in the universe is thought to have occurred sometime shortly after the Big Bang.
“We think ‘sideline quasars’ located out of the telescope’s view reionized intergalactic helium gas from different directions, preventing it from gravitationally collapsing and forming new generations of stars,” he said. Shull likened the early universe to a hunk of Swiss cheese, where quasars cleared out zones of neutral helium gas in the intergalactic medium that were then “pierced” by UV observations from the space telescope.
The results of the new study also indicate the helium reionization era of the universe appears to have occurred later than thought, said Shull, a professor in CU-Boulder’s astrophysical and planetary sciences department. “We initially thought the helium reionization era took place about 12 billion years ago,” said Shull. “But now we think it more likely occurred in the 11 to 10 billion-year range, which was a surprise.”
A paper on the subject by Shull and Syphers was published online this week in the Astrophysical Journal.
The Cosmic Origins Spectrograph used for the quasar observations aboard Hubble was designed to probe the evolution of galaxies, stars and intergalactic matter. The COS team is led by CU Professor James Green of CASA and was installed on Hubble by astronauts during its final servicing mission in 2009. COS was built in an industrial partnership between CU and Ball Aerospace & Technologies Corp. of Boulder.
“While there are likely hundreds of millions of quasars in the universe, there are only a handful you can use for a study like this,” said Shull. Quasars are nuclei in the center of active galaxies that have “gone haywire” because of supermassive black holes that gorged themselves in the cores, he said. “For our purposes, they are just a really bright background light that allows us to see to the edge of the universe, like a headlight shining through fog.”
The universe is thought to have begun with the Big Bang that triggered a fireball of searing plasma that expanded and then become cool neutral gas at about 380,000 years, bringing on the “dark ages” when there was no light from stars or galaxies, said Shull. The dark ages were followed by a period of hydrogen reionization, then the formation of the first galaxies beginning about 13.5 billion years ago. The first galaxies era was followed by the rise of quasars some 2 billion years later, which led to the helium reionization era, he said.
The radiation from the huge quasars heated the gas to 20,000 to 40,000 degrees Fahrenheit in intergalactic realms of the early universe, said Shull. “It is important to understand that if the helium gas is heated during the epoch of galaxy formation, it makes it harder for proto-galaxies to hang on to the bulk of their gas. In a sense, it’s like intergalactic global warming.”
The team is using COS to probe the “fossil record” of gases in the universe, including a structure known as the “cosmic web” believed to be made of long, narrow filaments of galaxies and intergalactic gas separated by enormous voids. Scientists theorize that a single cosmic web filament may stretch for hundreds of millions of light years, an eye-popping number considering that a single light-year is about 5.9 trillion miles.
COS breaks light into its individual components — similar to the way raindrops break sunlight into the colors of the rainbow — and reveals information about the temperature, density, velocity, distance and chemical composition of galaxies, stars and gas clouds.
For the study, Shull and Syphers used 4.5 hours of data from Hubble observations of the quasar, which has a catalog name of HS1700+6416. While some astronomers define quasars as feeding black holes, “We don’t know if these objects feed once, or feed several times,” Shull said. They are thought to survive only a few million years or perhaps a few hundred million years, a brief blink in time compared to the age of the universe, he said.
“Our own Milky Way has a dormant black hole in its center,” said Shull. “Who knows? Maybe our Milky Way used to be a quasar.”
The first quasar, short for “quasi-stellar radio source,” was discovered 50 years ago this month by Caltech astronomer Maarten Schmidt. The quasar he observed, 3C-273, is located roughly 2 billion years from Earth and is 40 times more luminous than an entire galaxy of 100 billion stars. That quasar is receding from Earth at 15 percent of the speed of light, with related winds blowing millions of miles per hour, said Shull.
-CU-
[includeme src=”http://c1n.tv/boulder/media/bouldersponsors.html” frameborder=”0″ width=”670″ height=”300″]
Boulder using new ultraviolet light technology to safely treat wastewater
Dec 7th
The new ultraviolet (UV) light disinfection system will replace the existing chlorine gas and sulfur dioxide gas systems, which have been in use since 1990 and pose a significant safety risk. The new technology is more efficient and eliminates the need to store and use hazardous gases. The UV light is a highly effective disinfectant for bacteria, viruses and protozoa.
“The new UV disinfection system is a major milestone for the facility and demonstrates the city’s commitment to continuous operational improvements that meet evolving community and regulatory needs,” said Director of Public Works for Utilities Jeff Arthur.
The Wastewater Treatment Facility improvements also include mechanical and electrical upgrades to the wastewater digester complex and headworks facility. The improvements are funded by a $9.2 million revenue bond and are expected to reduce long-term operating costs. Construction began in July 2011 and is currently on schedule to be completed in March 2013.
Wastewater from the community’s sanitary sewer systems is collected at the Wastewater Treatment Facility, where it is sent through a 20-hour, multi-stage treatment process. The facility treats an average of 12.5 million gallons of wastewater per day. In September 2012, the city’s Wastewater Treatment Facility received a Plant Performance Award from the Rocky Mountain Water Environment Association (RMWEA) in recognition of the facility’s commitment to outstanding maintenance, operations and public relations.
For more information about the Wastewater Treatment Facility improvements or to schedule a group tour, contact Wastewater Treatment Coordinator Chris Douville at 303-413-7341.
[includeme src=”http://c1n.tv/boulder/media/bouldersponsors.html” frameborder=”0″ width=”670″ height=”300″]
CU-BOULDER AND NASA’S SPACE SHUTTLE PROGRAM: TRIUMPHS AND TRAGEDIES
Jul 5th
Of the 19 astronaut-affiliates from CU — 18 from CU-Boulder and one from University of Colorado Colorado Springs — 16 flew on a total of 40 NASA space shuttle missions. The two who flew the most shuttle missions were Jim Voss, (M.S. aerospace engineering, 1974) a current scholar in residence at CU-Boulder who flew five missions, as did CU alumna Marsha Ivins (B.S. aerospace engineering, 1973).
Vance Brand, a Longmont native with two CU-Boulder degrees (B.A. business 1953, B.S. aerospace, 1960), began his astronaut career with the Apollo program — he flew on the historic Apollo-Soyuz mission that brought together astronauts and cosmonauts in space in 1981 — and went on to command three space shuttle flights.
Two CU-Boulder astronaut-alumni died aboard space shuttles. In 1986, Ellison Onizuka (B.S., M.S. aerospace engineering, 1969), was killed when Challenger exploded 73 seconds after liftoff, an event witnessed by millions around the world. In 2003, Kalpana Chawla (Ph.D. aerospace engineering, 1988) perished when Columbia disintegrated over Texas during Earth re-entry.
CU-Boulder’s Air Force ROTC honors the two fallen astronauts annually on campus with a color guard and wreath-laying ceremony.
A celebrated university reunion in space occurred on Dec. 2, 1990, when Columbia blasted off with three CU astronaut-alums. Brand, the Columbia space shuttle commander, was joined by mission specialist John “Mike” Lounge (M.S. astrogeophysics, 1970) and payload specialist Sam Durrance (Ph.D., astrogeophysics 1980) as part of the seven-man crew on the ASTRO-1 mission. Toting four telescopes in the cargo bay, the shuttle mission was the first ever dedicated to astronomy.
In addition to its prominent role in the astronaut program, CU-Boulder has flown dozens of science payloads on NASA’s 135 space shuttle missions. BioServe Space Technologies, a NASA-funded center in the aerospace engineering sciences department, has launched experiments onboard space shuttles 39 times since 1991, using the low-gravity of Earth orbit as a testing ground for a variety of agricultural, biomedical and educational payloads.
BioServe has worked with industrial and academic partners on experiments ranging from bone loss mitigation and the development of new antibiotics to K-12 educational payloads involving butterflies and spiders that drew the participation of more than a million students around the world. BioServe personnel have trained dozens of astronauts to operate their experimental hardware in space, both on the shuttle and the International Space Station.
NASA space shuttles also toted two key instruments developed by teams led by CU-Boulder faculty for the Hubble Space Telescope. The launch of Hubble aboard Atlantis in 1990 included a high-resolution spectrograph designed and built by a team led by CU-Boulder retired Professor John “Jack” Brandt of the Laboratory for Atmospheric and Space Physics. The instrument broke down wavelengths of light emanating from distant celestial objects to determine their compositions, motions and temperatures to help astronomers understand the conditions of the early universe.
Fittingly, the final Hubble repair mission launched in 2009 included a $70 million instrument designed by a CU-Boulder team and constructed with the help of Boulder’s Ball Aerospace & Technologies Corp., which also built the high resolution spectrograph launched on Hubble in 1990. Known as the Cosmic Origins Spectrograph, the CU instrument is being used to probe the fossil record of gases in the early universe for clues to the formation and evolution of galaxies, stars and planets, according to principal investigator and CU-Boulder Professor James Green of the Center for Astrophysics and Space Astronomy.
In 1989, the space shuttle Atlantis carried NASA’s Galileo spacecraft into orbit, the first leg of a six-year journey to Jupiter and its moons. The science instruments included two CU-Boulder ultraviolet spectrographs designed and built by LASP at a cost of $3.5 million under the direction of retired Professor Charles Hord and which were used for research ranging from analyzing complex organic molecules in the Jovian system to documenting the activity of volcanoes on one of Jupiter’s moons, Io.
In 1991, Discovery launched the Upper Atmosphere Research Satellite carrying seven instruments, including an $8 million instrument called the Solar Stellar Irradiance Comparison Experiment, or SOLSTICE, designed and built by LASP. The satellite went on to make accurate measurements of the sun in the ultraviolet and far UV light for a full 11-year solar cycle, allowing scientists to better understand the effects of solar radiation on Earth’s atmosphere and climate, said SOLSTICE Mission Manager Tom Sparn.
CU-Boulder’s LASP also built and flew two space shuttle payloads — one in 1998 aboard Columbia and a second in 2001 on Endeavour — that allowed scientists and students to explore the gentle collisions of particles of dust in space. The experiment provided new insights into the fundamental processes thought to have helped form planetary rings and perhaps played a role in the earliest stages of planet formation.
In addition, a small satellite designed and built by a LASP team that was to be deployed from the Challenger space shuttle in 1986 to orbit Earth and observe Halley’s comet was lost during the tragic explosion.
CU also flew experiments targeting the mechanics of granular material three times on space shuttles — in 1996, 1997 and 2003. Led by civil, environmental and architectural engineering Professor Stein Sture, now CU-Boulder’s vice chancellor for research, and managed by LASP, the tests allowed scientists to observe the behavior and cohesiveness of granular materials in microgravity and have led to a better understanding of how Earth’s surface responds during earthquakes and landslides. The 2003 mission successfully returned data from the in-flight experiments, but the seven astronauts and experimental hardware were lost when Columbia disintegrated during re-entry.
CU-Boulder’s involvement with the space shuttle program also included three payloads designed, built and flown by students, primarily undergraduates, from the Colorado Space Grant Consortium headquartered in aerospace engineering sciences. The first payload, dubbed ESCAPE, and which flew on Discovery in 1993, measured the sun’s effects on Earth’s atmosphere using a spectrometer to record extreme UV solar radiation and a camera to photograph the sun. The effort included the participation of nearly 100 students, primarily undergraduates, over a two-year span.
ESCAPE-2, flown on Atlantis in 1994, was a follow-on version of the Escape 1 payload that probed how solar radiation affected Earth’s thermosphere, a portion of Earth’s upper atmosphere. The payload involved about 75 students, mostly undergraduates, said Colorado Space Grant Consortium Director Chris Koehler.
A third CU-Boulder student-built space shuttle payload known as DATA-CHASER, was a two-part experiment launched aboard Discovery in 1997. The payload included hardware to test advanced remote technologies, as well as instruments to measure the sun in far UV wavelengths. DATA-CHASER was designed and built and tested by dozens of CU-Boulder students, primarily undergraduates, over a three-year span.
So what’s on deck at CU-Boulder following the end of NASA’s space shuttle program, in terms of both manned and unmanned flight vehicles? Hardware and experiments developed by BioServe already are manifested on various international resupply vehicles traveling to the International Space Station as well as on U.S. spacecraft now under development, said BioServe Director Louis Stodieck.
In August 2010 CU-Boulder was one of nine institutions selected by the Federal Aviation Administration to participate in a newly formed Center of Excellence for Commercial Space Transportation. The center focuses on four major research areas: space launch operations and traffic management; launch vehicle systems; commercial human space flight; and space commerce, including law, insurance, policy and regulation. All are aimed at ensuring safe and efficient private human space flight for non-NASA missions, said aerospace engineering Professor Dave Klaus, who directs the new CU-Boulder center.
CU-Boulder also is involved in a research partnership with Sierra Nevada Corp. of Louisville, Colo., which is designing and building a manned spacecraft called the Dream Chaser intended to replace the space shuttle for transporting humans and cargo into low-Earth orbit. Sierra Nevada has received about $200 million in NASA contracts to design and build the vehicle, which will be launched vertically and can land on conventional runways.
As part of its collaboration, Sierra Nevada is funding a CU team led by Klaus to develop methods for evaluating safety and operational aspects of the spacecraft. Klaus’ lab has a mock-up cockpit section of the Dream Chaser being used to test the ergonomic layout for instrument displays and controls. The students on the project are being advised by CU-Boulder’s Voss — who also is a vice president at Sierra Nevada Corp. — and his colleague Joe Tanner, both of whom joined the CU-Boulder faculty after retiring as NASA astronauts.
CU-Boulder currently is housing a full-scale mock-up of the Dream Chaser based on an earlier design of the spacecraft, as well as a 15 percent scale model that was successfully flight tested by a team including Sierra Nevada engineers and CU aerospace engineering faculty and students in December 2010. The hope of Sierra Nevada and CU-Boulder is that the Dream Chaser will provide routine crew transportation to and from the International Space Station as NASA turns its focus to deep space exploration missions.
In December 1990, when the space shuttle Columbia launched, Commander Vance Brand took with him a 10,000-year-old Paleo-Indian spear point that had been discovered on Colorado’s eastern plains. One wonders what the thundering liftoff of a NASA space shuttle might have looked like through the eyes of the earliest Americans, and what the next 10,000 years holds for human exploration of space in the solar system and beyond.
For more information visit the “CU in Space” website at http://www.colorado.edu/news/reports/space/.