![]() ![]() The research published in MNRAS favors the white dwarf merger scenario for Type 1a supernova events. Most astronomers agree that these events occur in binary systems with two stars, but while some suspect that the supernovae occur when the corpse of an old star, called a white dwarf, gravitationally attracts matter from its companion star until it reaches a critical mass and explodes, others argue that Type 1a explosions occur when two white dwarfs merge. These observations were crucial for pinpointing the distance of these events. Then they used the Keck telescopes, also located on Mauna Kea, to observe the galaxies where these explosions occurred. This is an inset from the deep field image. Right image: One the 150 supernovae collected in the team’s sample. Left image: The Subaru Deep Field, is a 0.25-square-degree field composed of 150,000 galaxies. Each run yielded about 40 supernovae among 150,000 galaxies. They pointed the ground-based telescope, located atop Hawaii’s Mauna Kea, toward a single field in the sky that was approximately the size of the full moon. To find the distant samples, an international team of astronomers exploited the enormous light collecting power of the Subaru Telescope's Prime Focus Camera (Suprime-Cam) on four separate occasions. It’s exciting for us to be able to study supernovae that are among the nearest, and now some of the most distant in the Universe, to see how their properties may have evolved with time," says co-author Alex Filippenko, a Professor of Astronomy at the University of California, Berkeley (UCB) and member of the Palomar Transient Factory team. "Recently, our Palomar Transient Factory discovered the closest Type 1a supernova in 25 years, just 21 million light years away in the Pinwheel Galaxy. "Over the past decade we used Type 1a supernovae to determine that the universe is actually accelerating in its expansion, under the influence of mysterious dark energy, but the nature of these events themselves is poorly understood and there is a fierce debate about how these explosions ignite," says co-author Dovi Poznanski, an Einstein Postdoctoral Fellow at the Lawrence Berkeley National Laboratory's (Berkeley Lab's) Computational Cosmology Center. In fact, Type 1a events were crucial evidence for showing that the universe is accelerating in its expansion under influence of dark energy, a result which earned the discoverers the 2011 Nobel Prize in Physics today (Tuesday, Oct. Because Type 1a supernovae are consistent in their intrinsic brightness and in their other observed properties across the cosmos, astronomers use them as “standard candles” to determine the distance of objects in the sky. Supernovae are important because they produce essentially all elements in the Universe that are heavier than oxygen. The paper, authored by a team of American, Israeli and Japanese astronomers, was published in the October 2011 issue of Monthly Notices of the Royal Astronomical Society (MNRAS). These events reveal that a particular breed of cosmic explosions, called Type 1a supernovae, occurred five times more frequently when the universe was young than they do today. An international team of astronomers has exposed the largest sample of distant supernovae ever found-150 events, many of which are located about 10 billion light years away from Earth. Freedom of Information Act (FOIA) files in 1975 revealed possible CIA influence in NET's refusal to distribute the film. Despite having permits from both the State & Treasury Depts., Cohen's 1963 through 1971 tax returns were audited by the Internal Revenue Service which revealed no liability. The film’s 1965 screening as "Three Faces of Cuba" on over 100 National Educational TV (NET) stations led to violent protests by anti-Castro exiles, followed by hearings before federal agencies, & non-inclusion by the NET in the usual distribution of its programs to the schools. The film's production had to overcome obstacles such as Kodak's selling the Producer defective raw stock & the loss of the work print from an insured Railway Express shipment. Returning to the US, Cohen interviewed an upper class exile who requested anonymity due to the family he left behind in Cuba. & Cuban Foreign Ministry to film the daily lives of upper, middle and lower class Cubans. In 1963 & 1964 Robert Carl Cohen became the first US filmmaker authorized by both the US State Dept.
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