(Press-News.org) Pasadena, CA—A team of researchers including Carnegie's Mansi Kasliwal and John Mulchaey used a novel astronomical survey software system—the intermediate Palomar Transient Factory (iPTF)—to link a new stripped-envelope supernova, named iPTF13bvn, to the star from which it exploded. The iPTF team also pinpointed the first afterglow of an explosion called a gamma-ray burst that was found by the Fermi satellite. Their work will be published by The Astrophysical Journal Letters in two papers led by Yi Cao and Leo Singer, both of the California Institute of Technology.
Their findings reflect the first time a star has been linked to the resulting explosion for this type of supernova, called Type Ib. The discovery offers very important answers about how this supernova type is formed, a problem that has eluded scientists for years.
About a third of all supernovae of massive stars are of the Type Ib. There are several theoretical models as to how they are formed, including mass transfer due to solar winds between a pair of binary stars. It is thought that the progenitors are either massive helium stars or a type of very large, very hot stars known as Wolf Rayet stars.
"Pinpointing a progenitor star at exactly the same location as a Type Ib supernova was the best way to test the theories about the genesis of this type of explosion," Kasliwal said. "Now we need to patiently wait for the supernova to fade away and see if the star disappears."
The new supernova was discovered in mid-June. No explosive light source was detected even a day earlier. Baby pictures of this one-day-old supernova were promptly taken by telescopes in the radio, X-ray, ultra-violet, and infrared wavelengths, providing vital clues about its origins.
Detailed analysis of different types of observations of the supernova confirmed that it was, indeed, a Type Ib, and that it reached full luminosity two weeks from its initial explosion. The team detected a progenitor candidate for the explosion in Hubble Space Telescope imaging, linking the supernova to its predecessor star. Future imaging will help identify whether this progenitor was a single star, a binary star, or a star cluster. The team thinks that their observations are consistent with the progenitor having been a Wolf Rayet star. If so this would be a breakthrough discovery.
The subject of the team's second paper using data from the new software system is a gamma ray burst afterglow called iPTF13bxl.
Gamma ray bursts are high-energy explosions that form some of the brightest celestial events. They can signify energy released during a supernova. Each burst is followed by an afterglow, which emits lower wavelength radiation than the original explosion.
Soon after the detection of a gamma-ray burst by the Fermi satellite, the team started hunting for the afterglow over a huge field more than 360-times the size of the full moon. They then had to narrow a list of more than 27,000 gamma-ray burst candidates down to a single afterglow. Follow-up research confirmed the relationship between the iPTF13bxl afterglow and a particular gamma-ray burst called GRB130702A.
The team then used the Magellan telescope to find the afterglow's so-called redshift value, which is a measurement of how much the light from it that reaches us on Earth has been stretched by the expansion of the universe. Thus, it reveals the afterglow's distance and tells astronomers where to look for an object, such as a supernova, which might emerge in the wake of the explosion.
"The sophisticated intermediate Palomar Transient Factory software we used to identify iPTF13bxl now prepares us to locate about 10 gamma-ray bursts every year going forward," said Mulchaey. "And future endeavors could help us identify other, fainter signatures, such as those accompanying the merger of binary neutron stars."
The afterglow discovery was an important milestone on the road to the goal of being able to detect light from gravitational waves in the cosmos, for which scientists have been searching for decades.
INFORMATION:
The iPTF13bvn work was supported by two Hubble Fellowships, a Carnegie-Princeton Fellowship, and a NSF Astronomy and Astrophysics Postdoctoral Fellowship, as well as grants from ISF, BSF, GIF, Minerva, the EU, and the NSF, in addition to a Kimmel Award.
The iPTF13bxl work was supported by NSF, the Hubble Fellowship, the Carnegie-Princeton Fellowship, the Israeli Ministry of Science, the I-CORE program, and the RCSA Cottrell Scholar Award.
This work was based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Intermediate Palomar Transient Factory project, a scientific collaboration among the California Institute of Technology, Los Alamos National Laboratory, the University of Wisconsin, Milwaukee, the Oskar Klein Center, the Weizmann Institute of Science, the TANGO Program of the University System of Taiwan, and the Kavli Institute for the Physics and Mathematics of the Universe.
The intermediate Palomar Transient Factory (iPTF)—led by the California Institute of Technology (Caltech)—started searching the skies for certain types of stars and related phenomena in February. The iPTF was built on the legacy of the Palomar Transient Factory (PTF), designed in 2008 to systematically chart the transient sky by using a robotic observing system mounted on the 48-inch Samuel Oschin Telescope on Palomar Mountain near San Diego, California.
The Carnegie Institution for Science (carnegiescience.edu) is a private, nonprofit organization headquartered in Washington, D.C., with six research departments throughout the U.S. Since its founding in 1902, the Carnegie Institution has been a pioneering force in basic scientific research. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.
New survey tools unveil 2 celestial explosions
2013-10-16
ELSE PRESS RELEASES FROM THIS DATE:
Participation in cardiac rehab program can result in gains for recovery in stroke patients
2013-10-16
Montreal — Stroke patients who participate in a cardiac rehabilitation program for six months make rapid gains in how far and fast they can walk, the use of weakened limbs and their ability to sit and stand, according to a study presented today at the Canadian Stroke Congress.
On average, participants saw a 21-per-cent improvement in the strength and range of motion of weakened limbs; a 19-per-cent improvement in walking speed; and a 16-per-cent improvement in the distance they could walk.
"There should be a seamless referral of patients with mild to moderate effects ...
Just ask the animals!
2013-10-16
This news release is available in German. Many animals are adapting to human encroachment of their natural habitats. Carnivores in particular require territories of sufficient size and so are often forced to move between numerous small habitat patches. To date, scientists often use mathematical models to predict these important routes, but fishers fitted with GPS sensors are now showing that their calculations may be missing the mark if they ignore animal behaviour.
Corridors are spaces that receive too little attention and yet are vitally important. How else would ...
UMD researchers address economic dangers of 'peak oil'
2013-10-16
COLLEGE PARK, Md. -- Researchers from the University of Maryland and a leading university in Spain demonstrate in a new study which sectors could put the entire U.S. economy at risk when global oil production peaks ('Peak Oil"). This multi-disciplinary team recommends immediate action by government, private and commercial sectors to reduce the vulnerability of these sectors.
While critics of Peak Oil studies declare that the world has more than enough oil to maintain current national and global standards, these UMD-led researchers say Peak Oil is imminent, if not already ...
Poor rural youth in Haiti are rich in family ties, rooted in their own culture
2013-10-16
URBANA, Ill. – Haitian teens, especially those who live in the country's rural areas, are among the poorest persons in the Western Hemisphere, but they are rich in their family relationships and strongly rooted in their own culture, a University of Illinois study finds.
"It's true that rural Haitian teens didn't directly suffer the major trauma of the 2012 earthquake, but they deal daily with the effects of poverty—not enough food, no money to go to school, a lack of electricity much of the time, little access to clinics or hospitals," said Gail M. Ferguson, a U of I ...
Keep your friends close, but…
2013-10-16
Counterintuitive findings from a new USC study show that the part of the brain that is associated with empathizing with the pain of others is activated more strongly by watching the suffering of hateful people as opposed to likable people.
While one might assume that we would empathize more with people we like, the study may indicate that the human brain focuses more greatly on the need to monitor enemies closely, especially when they are suffering.
"When you watch an action movie and the bad guy appears to be defeated, the moment of his demise draws our focus intensely," ...
Iraqi death toll from 2003-2011 war and subsequent conflict estimated at half a million
2013-10-16
A scientific study calculating Iraqi deaths for almost the complete period of the US-led war and subsequent occupation published in PLOS Medicine this week reports that close to half a million Iraqi deaths are directly or indirectly attributable to the conflict. A team of researchers from Iraq and the US led by Amy Hagopian, of the University of Washington, conducted a survey in 2000 households across Iraq and used the data to estimate death rates for the two year-period before the war began in March 2003 and the subsequent years until mid-2011.
Estimates that extrapolate ...
Expert panel diagnosis for diagnostic test poorly described, experts not blinded to test under study
2013-10-16
Evaluation of diagnostic studies is often a challenge in diseases that are not defined by a specific test. Assessment of the accuracy of diagnostic tests is essential because they may be used to define who is considered to have a disease and receive treatment for it. However, measuring the accuracy of a diagnostic test requires an accurate gold standard, which defines which patients truly have and do not have the disease. Studies of diseases not defined by a specific test often rely on expert panels to establish the gold standard. In a systematic review and analysis of ...
Protective pathway identified to counter toxicity associated with Alzheimer's disease
2013-10-16
New research led by Marco Prado, PhD, of Western University has identified a pathway used by the brain to try to protect itself from toxicity that occurs with Alzheimer's disease (AD). Prado and his colleagues at the Robarts Research Institute and at the A.C. Camargo Cancer Center in Brazil have done extensive work on the role of prion protein. They found that toxicity of amyloid-β peptides, one of the major culprits in AD, can be decreased by preventing it from interacting with the prion protein. When a protein called stress-inducible phosphoprotein 1 (STI1) interacts ...
Penn researchers take first step toward a macular dystrophy gene therapy
2013-10-16
Vitelliform macular dystrophy, also known as Best disease, is one of a group of vision-robbing conditions called bestrophinopathies that affect children and young adults. Caused by inherited mutations in the BEST1 gene, these diseases cause severe declines in central vision as patients age.
With a new study, University of Pennsylvania researchers report "encouraging" findings that mark the first clear step in developing a gene therapy that could prevent vision loss or event restore vision in individuals suffering from these conditions.
The research, conducted in dogs, ...
Study finds high variability among primary care physicians in rate of PSA screening of older men
2013-10-16
"No organization recommends prostate-specific antigen (PSA) screening in men older than 75 years. Nevertheless, testing rates remain high," write Elizabeth Jaramillo, M.D., of the University of Texas Medical Branch, Galveston, and colleagues in a Research Letter appearing in the October 16 issue of JAMA. The authors examined whether PSA screening rates would vary substantially among primary care physicians (PCPs) and if the variance would depend on which PCP patients used.
Using complete Medicare Part A and B data for Texas, the researchers selected PCPs whose patient ...