Latest from the Fermi Telescope to be Presented at the American Physical Society Meeting in Denver, May 2-5, 2009

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Newswise — When its rocket lifted off from Cape Canaveral, FL on June 11, 2008, the Fermi Gamma-ray Space Telescope (formerly called GLAST) began its active life with short trip into orbit above the Earth, where it was safely delivered 75 minutes later. From a vantage 350 miles high, the Fermi telescope surveys the entire sky every three hours, detecting gamma rays, the highest-energy light in the universe.

The scientific aspirations for this telescope are higher still. It promises to help scientists better understand some of the most fundamental questions in astrophysics, including the origins of cosmic rays, the identity of dark matter in the universe, the workings of massive black holes at the centers of distant galaxies, and the origins of gamma-ray bursts, the most energetic explosions that are known in the universe.

Less than a year after launch, some of the first data from this powerful new astronomical tool are starting to become available. At the April Meeting of the American Physical Society (APS), which takes place from May 2-5, 2009 at the Sheraton Denver Hotel in downtown Denver, several talks will be devoted to data gathered by the telescope in its few months of operation.

In the opening plenary session of the April Meeting, Peter Michelson (Stanford University) will discuss results from the first eight months of Fermi's collected data. (Talk A1.1, http://meetings.aps.org/Meeting/APR09/Event/101637). Other specific highlights include:

A NEW LOOK BACK IN TIME (Talk T4.1)Gamma-ray bursts are mysterious but spectacular displays involving an extraordinary amount of energy. In just a few seconds, some gamma-ray bursts release more energy than our sun will emit over 10 billion years. Because they are so powerful, gamma ray bursts are also the most distant phenomena we can easily see -- detectable even from a distance of billions of light years. Believed to be caused by the collapse of massive stars, these bursts act as unique beacons illuminating the early universe. Their light may be able to tell us a lot about the first generation of stars and what the early universe was like.

So far astronomers have not figured out an exact mechanical explanation for these bursts, but the Fermi Gamma-ray Space Telescope promises to enhance our ability to study them. In Denver, Charles Meegan (USRA) will describe some of the first observations of gamma ray bursts with the new telescope, including a large one reported in the journal Science last month that exceeded the power of about 9,000 ordinary supernovae -- a blast that liberated more total energy than any seen before. (Talk T4.1, http://meetings.aps.org/Meeting/APR09/Event/102687).

VIOLENT BLACK HOLES AT THE CENTERS OF GALAXIES (Talk T4.2)Among the most violent displays in the universe come from compact objects known as blazars. These distant galaxies are notable for emitting a highly variable amount of energy, which is believed to originate from supermassive black holes at their centers. When clouds of dust, gas, and the occasional star fall into these supermassive black holes, they generate energetic jets of particles and light by processes not yet understood. If these energetic jets happen to point towards Earth, astronomers identify them as blazars. The light from blazars can be extremely intense and allows us to detect very distant sources that produced their emission when the universe was very young. This is one of the reasons why blazars are useful for studying the formation of galaxies and for probing the spaces in between galaxies.

The newly-launched Fermi Gamma-ray Space Telescope promises to detect a host of blazars and measure their properties with far more sensitivity than past telescopes. According to James Chiang of the SLAC National Accelerator Laboratory and the Kavli Institute for Particle Astrophysics and Cosmology, the Fermi telescope has discovered more blazars in its first nine months than the telescope on NASA's Compton Gamma Ray Observatory managed in a decade. Chiang will describe some of the details of these newly-detected blazars -- including the first-ever gamma-ray emissions detected from a blazar at the center of a cluster of galaxies. (Talk T4.2, http://meetings.aps.org/Meeting/APR09/Event/102688).

SOURCES OF GAMMA RAYS AND STAR FORMATION (Talk T4.3)The collapse of clouds of gas into massively dense cores under the influence of gravity is the standard picture of how new stars form. But there may be more to this picture than meets the eye. A second, opposing force of cosmic rays (super-accelerated particles) accelerated by the winds of massive short-lived stars, or in the dead remnants of these stars, may exert resisting forces on collapsing clouds, quenching star formation. Understanding such processes is just one of the questions being asked by scientists using the Large Area Telescope (LAT), one of two instruments on board the Fermi Gamma-ray Space Telescope.

The LAT is designed to study the gamma ray sky with greater sensitivity than has ever been done before. In Denver, Troy Porter (Santa Cruz Institute for Particle Physics and the University of California) will discuss the first eight months of this instrument's work identifying galactic and nearby extragalactic sources of gamma rays. Some of these gamma rays come from identifiable point sources, like powerful pulsars within our galaxy. About 80 percent of the gamma rays measured, however, are a diffuse background produced by cosmic rays interacting with interstellar gas and radiation fields within the Milky Way. But even diffuse sources can tell us a lot about the universe.

One early result of the Fermi observatory is that it is able to resolve diffuse gamma-ray emissions from a nearby galaxy called the Large Magellanic Cloud. As it turns out, about half of the gamma rays coming from this galaxy originate in a hot spot known as the 30 Doradus region. This is the most intense star-forming region within several million light years of Earth. It has a high concentration of short-lived massive stars that undergo rapid death, possibly producing a large number of cosmic rays in the process. Says Porter, understanding how these cosmic rays contribute to the life cycle of stars may reveal how our own world came into being. (Talk T4.3, http://meetings.aps.org/Meeting/APR09/Event/102689).

************************************************************REGISTERING AS A JOURNALISTMembers of the press who wish to attend the meeting for free should email Jason Bardi at [email protected]. Complimentary press registration will allow access to the pressroom and all scientific sessions. Public information officers, as usual, are welcome.

WEB SITES OF INTERESTThe April Meeting website is http://www.aps.org/meetings/april/index.cfm. The meeting program, including searchable abstracts can be accessed at http://meetings.aps.org/Meeting/APR09/Content/1380.

PRESSROOM INFORMATION---The meeting pressroom will be located in the Sheraton Denver hotel, Plaza Court 6. ---Pressroom hours: Sat-Mon, 730 a.m.-530 p.m.; Tues, 730 a.m.-noon---Pressroom phone number: 303-352-2420---Pressroom fax number: 303-352-2421---Breakfast and lunch food will be available in the pressroom Sat-Mon

PRESS CONFERENCES---Press conferences will be held Sat-Sun-Mon in Sheraton Denver hotel, Plaza Court 7. ---Contact James Riordon ([email protected], office: 301-209-3238, cell: 301-919-2173) for instructions for dialing in to press conferences remotely.---For a list of press conferences, email James Riordon ([email protected]) or Jason Bardi ([email protected]).

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ABOUT APSThe American Physical Society is the leading professional organization of physicists, representing more than 47,000 physicists in academia and industry in the United States and internationally. APS has offices in College Park, MD (Headquarters), Ridge, NY, and Washington, DC.

ABOUT AIPHeadquartered in College Park, MD, the American Institute of Physics is a not-for-profit membership corporation chartered in New York State in 1931 for the purpose of promoting the advancement and diffusion of the knowledge of physics and its application to human welfare.