Gamma-ray Bursts May Last Longer than Previously Thought

(Image - artist's conception of a gamma-ray burst)

Artist's conception of a gamma-ray burst. (Image: NASA.)

by Michael Wall

Gamma-ray bursts, the most powerful explosions in the universe since the Big Bang, are thought to last mere seconds or a few short minutes. But new data from the Fermi Gamma-ray Space Telescope show at least some of them have much more staying power.

In March, FGST's Large Area Telescope, or LAT—an incredibly sensitive gamma-ray and particle detector assembled at SLAC—spotted high-energy gamma rays from two separate bursts lasting many minutes after they occurred. Such burst durations have been observed only once before. In 1994, NASA's EGRET instrument picked up gamma rays 1.5 hours after a blast.

"With only one observation, you never know how often something happens," said SLAC physicist Roger Blandford, who works on the FGST project. "Now these delayed gamma rays are beginning to look like a common phenomenon."

Gamma-ray bursts are mysterious. Astronomers have proposed that they occur when massive stars run out of nuclear fuel and collapse into black holes, releasing intense jets of radiation. The collision of two neutron stars orbiting in a binary system is another possible source. FGST's observations could help scientists tease out the actual cause or causes.

The new data set is "an important constraint on the nature of these explosions," Blandford said. "The source of bursts such as these must remain active for a relatively long time. This means that certain explanations are not viable." Read more...

SLAC Procurement Update for Stimulus Funds

The Business Services Division has created new Web resources detailing procurement requirements for the $68.3 million stimulus funds received by SLAC from the Department of Energy under the American Recovery and Reinvestment Act. (See "From the Director: What a Difference in a Year!"). A key ARRA objective is to get the funding into the general economy quickly in a transparent manner. Toward this end, SLAC has modified business systems to meet ARRA challenges.

Planning and guidance documents have been posted to the Procurement Web site and the ARRA SharePoint site (restricted access). Useful information on ARRA guidelines is also published to these sites to help you keep abreast of the new and changing ARRA guidance.

For a summary of ARRA-related procurement and helpful guides, see the "ARRA Procurement Summary" announcement and "American Recovery and Reinvestment Act 2009" on the Procurement Web site. Please direct any procurement-related questions to Alan Kong (x 4138).

Editor's note: Thanks go to James Dee for his efforts in bringing this information together.

Get Ready for
Bike to Work Day

by Lauren Schenkman

You don't have to own any spandex or love the taste of powdered protein to become a bike commuter. Bike to Work Day on Thursday May 14 is the perfect opportunity to strap on your helmet and swap gas for pedal power, and you'll be rewarded for your efforts! Between 6:30 and 9 a.m., volunteers at the front gate will be handing out bike bags, energy bars, orange juice, bagels, bike literature and other freebies to SLACers arriving on two wheels.

"There are great benefits to biking," said Mike Woods, the event's organizer. He said that because he and his wife commute via bike regularly, their family needs only one car. "It's good for the environment and good for your health."

For those nervous about biking on Sand Hill Road, he said, "If you're willing to bike a little extra distance, you can pick a route that doesn't have you on a busy road." Bikers can plan a safe, stress-free route ahead of time using the map resources at the Bike to Work Day Web site, where you can also find tips on bike safety.

Thinking of making bike commuting a habit? Register before May 14 for "Let's Roll San Mateo County" to earn bike shop gift certificates, or grab some coworkers and sign up for Bike to Work Day's Team Bike Challenge.

After your ride, hit the showers—SLAC has men's and women's locker rooms and showers in Building 34, the Controls Building, located behind Building 24.

Events (see all | submit)

Today (10:00 a.m.) LCLS Special Seminar: Longitudinal Coherence Measurements at FLASH
Today (4:00 p.m.) How do Stars Explode? Mechanisms of Core-Collapse Supernovae
May 6 (12:30 p.m.) SASS: The Cantor Ternary Set
May 6 (12:30 p.m.) Special Seminar: Measurement of the CR Electron Spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
May 6 (1:30 p.m.) Theory Seminars: Reciprocity in AdS/CFT
May 6 (3:00 p.m.) Theoretical Physics Event: Interpretations of Fermi Data

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Announcements
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Lab Announcements

Community Bulletin Board

Training

Lab Training (calendar | register)

May 5 and 6 (8:00 a.m.) Basic Crane Operations and Rigger Training
Today (1:00 p.m.) Pressure Safety Training

Upcoming Workshops & Classes

MS Office 2007 Classes

News (submit)

Highlights of APS Meeting in Denver, May 2-5, 2009 AIP news release on Newswire
FLAST and the Photoelectric Effect: Extreme Ultraviolet Laser Challenges Einstein Wired
BLAST: Finding Starburst Galaxies Physics Today
Dark Matter 'Highway' Funnels Gas into Galactic Pileup Wired

<% Response.AddHeader "Last-modified", getArticleDate() 'Response.AddHeader "Last-modified","Mon, 01 Sep 1997 01:03:33 GMT" 'Monday, December 06, 2010 %>

View online at http://today.slac.stanford.edu/.

Gamma-ray Bursts May Last Longer than Previously Thought Artist's conception of a gamma-ray burst. (Image: NASA.) by Michael Wall Gamma-ray bursts, the most powerful explosions in the universe since the Big Bang, are thought to last mere seconds or a few short minutes. But new data from the Fermi Gamma-ray Space Telescope show at least some of them have much more staying power. In March, FGST's Large Area Telescope, or LAT—an incredibly sensitive gamma-ray and particle detector assembled at SLAC—spotted high-energy gamma rays from two separate bursts lasting many minutes after they occurred. Such burst durations have been observed only once before. In 1994, NASA's EGRET instrument picked up gamma rays 1.5 hours after a blast. "With only one observation, you never know how often something happens," said SLAC physicist Roger Blandford, who works on the FGST project. "Now these delayed gamma rays are beginning to look like a common phenomenon." Gamma-ray bursts are mysterious. Astronomers have proposed that they occur when massive stars run out of nuclear fuel and collapse into black holes, releasing intense jets of radiation. The collision of two neutron stars orbiting in a binary system is another possible source. FGST's observations could help scientists tease out the actual cause or causes. The new data set is "an important constraint on the nature of these explosions," Blandford said. "The source of bursts such as these must remain active for a relatively long time. This means that certain explanations are not viable." Read more... SLAC Procurement Update for Stimulus Funds The Business Services Division has created new Web resources detailing procurement requirements for the $68.3 million stimulus funds received by SLAC from the Department of Energy under the American Recovery and Reinvestment Act. (See "From the Director: What a Difference in a Year!"). A key ARRA objective is to get the funding into the general economy quickly in a transparent manner. Toward this end, SLAC has modified business systems to meet ARRA challenges. Planning and guidance documents have been posted to the Procurement Web site and the ARRA SharePoint site (restricted access). Useful information on ARRA guidelines is also published to these sites to help you keep abreast of the new and changing ARRA guidance. For a summary of ARRA-related procurement and helpful guides, see the "ARRA Procurement Summary" announcement and "American Recovery and Reinvestment Act 2009" on the Procurement Web site. Please direct any procurement-related questions to Alan Kong (x 4138). Editor's note: Thanks go to James Dee for his efforts in bringing this information together. Get Ready for Bike to Work Day by Lauren Schenkman You don't have to own any spandex or love the taste of powdered protein to become a bike commuter. Bike to Work Day on Thursday May 14 is the perfect opportunity to strap on your helmet and swap gas for pedal power, and you'll be rewarded for your efforts! Between 6:30 and 9 a.m., volunteers at the front gate will be handing out bike bags, energy bars, orange juice, bagels, bike literature and other freebies to SLACers arriving on two wheels. "There are great benefits to biking," said Mike Woods, the event's organizer. He said that because he and his wife commute via bike regularly, their family needs only one car. "It's good for the environment and good for your health." For those nervous about biking on Sand Hill Road, he said, "If you're willing to bike a little extra distance, you can pick a route that doesn't have you on a busy road." Bikers can plan a safe, stress-free route ahead of time using the map resources at the Bike to Work Day Web site, where you can also find tips on bike safety. Thinking of making bike commuting a habit? Register before May 14 for "Let's Roll San Mateo County" to earn bike shop gift certificates, or grab some coworkers and sign up for Bike to Work Day's Team Bike Challenge. After your ride, hit the showers—SLAC has men's and women's locker rooms and showers in Building 34, the Controls Building, located behind Building 24.	Events (see all \| submit) Today (10:00 a.m.) LCLS Special Seminar: Longitudinal Coherence Measurements at FLASH Today (4:00 p.m.) How do Stars Explode? Mechanisms of Core-Collapse Supernovae May 6 (12:30 p.m.) SASS: The Cantor Ternary Set May 6 (12:30 p.m.) Special Seminar: Measurement of the CR Electron Spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope May 6 (1:30 p.m.) Theory Seminars: Reciprocity in AdS/CFT May 6 (3:00 p.m.) Theoretical Physics Event: Interpretations of Fermi Data Access (see all) No access items today Announcements (see all \| submit) Lab Announcements All Sessions Cancelled for Incident Investigation Training SLAC Town Hall Meeting for Changes to Retirement Investment Options May 6 Product Recall: Dymo LabelWriter or Desktop Mailing Solution Power Adaptor Failures Community Bulletin Board Second LCLS Call for Proposals: Deadline May 15 SuperB Workshop Registration Open Registration Open: Ultrafast X-ray Summer School 2009 Training Lab Training (calendar \| register) May 5 and 6 (8:00 a.m.) Basic Crane Operations and Rigger Training Today (1:00 p.m.) Pressure Safety Training Upcoming Workshops & Classes MS Office 2007 Classes News (submit) Highlights of APS Meeting in Denver, May 2-5, 2009 AIP news release on Newswire FLAST and the Photoelectric Effect: Extreme Ultraviolet Laser Challenges Einstein Wired BLAST: Finding Starburst Galaxies Physics Today Dark Matter 'Highway' Funnels Gas into Galactic Pileup Wired
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<% Response.AddHeader "Last-modified", getArticleDate() 'Response.AddHeader "Last-modified","Mon, 01 Sep 1997 01:03:33 GMT" 'Monday, December 06, 2010 %> View online at http://today.slac.stanford.edu/.