The M87 jet as seen in the optical by the Hubble Space Telescope (left) and in x-rays by the Chandra X-Ray Observatory.

A Mystery of Gamma Rays

by Ken Kingery

Scattered across the universe, certain galaxies emit enormously powerful jets of relativistic particles intertwined with bursts of gamma rays. Although thousands of these jets have been observed, the precise mechanism by which gamma rays are created has mystified astronomers for more than 15 years. Recently, a team of SLAC scientists made a surprising discovery about the source of the most powerful of these gamma rays that raises as many questions as it answers.

One of the main questions researchers seek to answer about these unique radio galaxies—also known as "blazars" or "quasars" depending on the jet's orientation—is where, exactly, the gamma rays are created. Researchers believe that a black hole at the center of each quasar emits the jet of particles including electrons, positrons and protons. For years they postulated that the gamma rays were created within this jet stream. But later studies led some to believe that the gamma rays were instead produced by a yet unknown physical phenomenon very near the edge of the black hole itself. Now, SLAC researchers Teddy Cheung and Lukasz Stawarz, in collaboration with Daniel Harris at the Harvard-Smithsonian Center for Astrophysics, believe they have finally nailed down the location of gamma ray production.

"It's much farther down the jet than most scientists thought," said Cheung. "It's a very surprising result." Read more...

SLAC Welcomes
New Employees

Click on image for larger version.

SLAC welcomed 13 new employees last week at orientation. From left to right, they are: Andrew May, Madhu Swaminathan, Brian Moritz, Gail Fong, David Simas, Barbara Fuller, Linda (Curry) Kizziah, Dora Yu, Kirk Bertsche, Lauren Elizabeth Alsberg, Michelle Whiting, Kimberely Swanson, and Simon Ovrahim.

Fiscal Year-End Procurement Deadlines

by Bob Todaro

Please consider the following dates and dollar amounts if you are planning to submit a purchase requisition that needs to be delivered and accepted before the end of Fiscal Year 07 (September 28, 2007). Requisitions must be entered into PeopleSoft on or before these dates:

Requisition value between $25, 000 and $99,999: Friday, September 7th.

Requisition value of less than $25,000: Friday, September 14th.

Any requisition entered into PeopleSoft after these dates will be processed with a delivery date of October 1st or later.

Requisition value of $100,000 or greater: Due to Purchasing Department processing time (30 to 45 days) and Department of Energy/Stanford Site Office review and approval requirements (2 to 5 days), these requisitions will be processed with a delivery date of October 1st or later.

For more information, please contact Purchasing Officer Bob Todaro at x2425 or rocker@slac.stanford.edu.

Jonathan Visits ATLAS

Click on image for larger version.

Jonathan Dorfan with the SLAC
A Toroidal LHC ApparatuS (ATLAS) group at CERN this week.

Respectful Workplace Policy Posters
Spring Up Around Lab

by Charlotte Carlson

Click on poster for larger version.

Have you noticed the colorful R-E-S-P-E-C-T posters around the SLAC campus? Inspired by Aretha Franklin’s song RESPECT, the posters are a reminder that one of the reasons SLAC is a great place to work is its Respectful Workplace Policy.

A respectful workplace is one in which "Everyone is important; employees treat each other with respect; everyone—especially people in authority—serves as a role model; everyone can share concerns without fear of retaliation; and management listens."

To encourage a respectful workplace, employees and users can:

- Catch people doing something
   right.
- Don't yell unless the building is
   on fire!
- Fix the problem, not the blame.
- Walk around a problem to see it
   from someone else's point of
   view.
- Take responsibility for their own
   mistakes and move on.
- Keep a sense of humor.
- Avoid gossip.
- Adopt the "24 hour gap" rule—
   wait 24 hours before sending
   an angry email; then don't send
   it!

If you would like posters for your area, please contact Charlotte Carlson in Human Resources at x2265.

Events (see all | submit)

September 11: (12:30 p.m.) Experimental Seminar: Progress Towards a Measurement of the Electron

Access (see all)

Announcements
(see all | submit)

Lab Announcements

Community Bulletin Board

Stanford Prevention Research Center Health Screening & Recruitment Fair

News (see all | submit)

The ILC Reference Design Report is Now Official ILC NewsLine
Saturn's Dizzying Spin Hints at Quick Birth New Scientist
No End in Sight for FY 2008 Appropriations Bills AIP FYI

<% 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/.

The M87 jet as seen in the optical by the Hubble Space Telescope (left) and in x-rays by the Chandra X-Ray Observatory. A Mystery of Gamma Rays by Ken Kingery Scattered across the universe, certain galaxies emit enormously powerful jets of relativistic particles intertwined with bursts of gamma rays. Although thousands of these jets have been observed, the precise mechanism by which gamma rays are created has mystified astronomers for more than 15 years. Recently, a team of SLAC scientists made a surprising discovery about the source of the most powerful of these gamma rays that raises as many questions as it answers. One of the main questions researchers seek to answer about these unique radio galaxies—also known as "blazars" or "quasars" depending on the jet's orientation—is where, exactly, the gamma rays are created. Researchers believe that a black hole at the center of each quasar emits the jet of particles including electrons, positrons and protons. For years they postulated that the gamma rays were created within this jet stream. But later studies led some to believe that the gamma rays were instead produced by a yet unknown physical phenomenon very near the edge of the black hole itself. Now, SLAC researchers Teddy Cheung and Lukasz Stawarz, in collaboration with Daniel Harris at the Harvard-Smithsonian Center for Astrophysics, believe they have finally nailed down the location of gamma ray production. "It's much farther down the jet than most scientists thought," said Cheung. "It's a very surprising result." Read more...

SLAC Welcomes New Employees Click on image for larger version. SLAC welcomed 13 new employees last week at orientation. From left to right, they are: Andrew May, Madhu Swaminathan, Brian Moritz, Gail Fong, David Simas, Barbara Fuller, Linda (Curry) Kizziah, Dora Yu, Kirk Bertsche, Lauren Elizabeth Alsberg, Michelle Whiting, Kimberely Swanson, and Simon Ovrahim. Fiscal Year-End Procurement Deadlines by Bob Todaro Please consider the following dates and dollar amounts if you are planning to submit a purchase requisition that needs to be delivered and accepted before the end of Fiscal Year 07 (September 28, 2007). Requisitions must be entered into PeopleSoft on or before these dates: Requisition value between $25, 000 and $99,999: Friday, September 7th. Requisition value of less than $25,000: Friday, September 14th. Any requisition entered into PeopleSoft after these dates will be processed with a delivery date of October 1st or later. Requisition value of $100,000 or greater: Due to Purchasing Department processing time (30 to 45 days) and Department of Energy/Stanford Site Office review and approval requirements (2 to 5 days), these requisitions will be processed with a delivery date of October 1st or later. For more information, please contact Purchasing Officer Bob Todaro at x2425 or rocker@slac.stanford.edu.	Jonathan Visits ATLAS Click on image for larger version. Jonathan Dorfan with the SLAC A Toroidal LHC ApparatuS (ATLAS) group at CERN this week. Respectful Workplace Policy Posters Spring Up Around Lab by Charlotte Carlson Click on poster for larger version. Have you noticed the colorful R-E-S-P-E-C-T posters around the SLAC campus? Inspired by Aretha Franklin’s song RESPECT, the posters are a reminder that one of the reasons SLAC is a great place to work is its Respectful Workplace Policy. A respectful workplace is one in which "Everyone is important; employees treat each other with respect; everyone—especially people in authority—serves as a role model; everyone can share concerns without fear of retaliation; and management listens." To encourage a respectful workplace, employees and users can: - Catch people doing something right. - Don't yell unless the building is on fire! - Fix the problem, not the blame. - Walk around a problem to see it from someone else's point of view. - Take responsibility for their own mistakes and move on. - Keep a sense of humor. - Avoid gossip. - Adopt the "24 hour gap" rule— wait 24 hours before sending an angry email; then don't send it! If you would like posters for your area, please contact Charlotte Carlson in Human Resources at x2265.	Events (see all \| submit) September 11: (12:30 p.m.) Experimental Seminar: Progress Towards a Measurement of the Electron Access (see all) No access to the SPEAR parking area - Sept. 7 & 10 Periodic closure of South Klystron Gallery Road Many Research Yard areas to lose power, Sept. 6 - 17 Upcoming Traffic Disruption on Sec 30 Road Parking lot between B120 and B140 closed Alpine Gate & PEP Ring Road closed Gates 17 & 30 open 24-7 Research Yard bisected Announcements (see all \| submit) Lab Announcements Stanford Center for Professional Development Autum Registration Voicemail System Upgrade and Outage Influenza Vaccine Interlab 2007 Workshop, "Bringing the Art of Science to the Web" (Oct. 1-3, LANL) Community Bulletin Board Stanford Prevention Research Center Health Screening & Recruitment Fair News (see all \| submit) The ILC Reference Design Report is Now Official ILC NewsLine Saturn's Dizzying Spin Hints at Quick Birth New Scientist No End in Sight for FY 2008 Appropriations Bills AIP FYI
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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/.