November 2, 2009 — Fermi Telescope Celebrates First Year's Results with Cosmic Reflection Concert

Reflecting on cosmology
and the story of the universe
Image by Pierre Schwob
(Click thumbnail to enlarge)

The 2009 Fermi International Science Symposium will be held in Washington, D.C. , Nov. 2-5, 2009, looking back on the first year of spectacular results from the Fermi Gamma-ray Space Telescope (formerly known as GLAST).

An extraordinary highlight of this symposium will be a live public concert on Nov. 2^nd at the John F. Kennedy Center for the Performing Arts in Washington, D.C. This concert, produced and sponsored by Pierre Schwob, founder and CEO of Classical Archives in Palo Alto, Ca., will feature two works by composer Nolan Gasser (Stanford Ph.D. in Musicology, 2001)—GLAST Prelude, Op.12, for brass quintet and the World Premiere of Cosmic Reflection: A Narrated Symphony, Op.15.

Read full story.

September, 2009 — Peter Michelson succeeds Blas Cabrera as HEPL Director

HEPL Director Transition Ceremony.
Following a luncheon featuring Chinese
cuisine, GP-B Principal Investigator,
Francis Everitt (left), reads the fortune
cookie messages for outgoing HEPL
Director, Blas Cabrera (center), and for
incoming director, Peter Michelson (right).
(Click on the thumbnail above to view
full-sized photo.)

On September 1, 2009, physics professor Peter Michelson became the new Director of HEPL. Professor Michelson is the tenth person to oversee and direct the lab's activities during its 58-year history, beginning in 1951 when the lab was officially founded as the Stanford "High Energy Physics Lab" (also abbreviated HEPL). In 1990, the lab was renamed the" W.W. Hansen Experimental Physics Lab," honoring pioneering physicist and engineer, William W. Hansen.

Over the years, the directorship of HEPL has evolved into a three-year, rotating position among the faculty members whose research programs are administered by HEPL. Having just completed his term as HEPL Director, Professor Blas Cabrera is now looking forward to devoting more time to his research on the search for cryogenic dark matter and weakly interactive massive particles (WIMPs). Professor Michelson, who is Principal Investigator of the NASA-funded Fermi Gamma-ray Large-Area Space Telescope program, has kindly agreed to take the helm of HEPL for the next three years.

To commemorate this transition in HEPL leadership, a brief ceremony was held on August 24, 2009 in the Physics/Astrophysics main conference room. The highlight of the ceremony came when Professor Francis Everitt, Principal Investigator of the Gravity Probe B program, picked out two fortune cookies—one for the outgoing HEPL director and one for the incoming HEPL director—and read them aloud. Both fortunes were uncannily apt for their respective recipients.

You can read more about the colorful history of HEPL and its previous directors on the About HEPL page of this web site.

August 2009 —Fermi Gamma-ray Space Telescope results prominently featured in 8/14 issue of AAAS Science

Pulsars in our Galaxy newly
discovered by the Fermi LAT
Telescop. Image: NASA/U.S.
DOE/Fermi LAT Collaboration
/Sonoma State University/
Aurore Simonnet. (Click on
the thumbnail above to view
larger cover image.)

The extraordinary results of the Fermi Gamma-ray Large Area Telescope in detecting and thereby confirming the predicted presence of gamma-ray pulsars in our galaxy was the cover story in the August 14, 2009 issue of Science, the journal of the American Association for the Advancement of Science (AAAS). In addition to the cover story article about the detection of 16 " gamma-ray-only" pulsars, the issue contains two related research reports, as well as an Astronomy Perspectives overview article by astronomer, Jules Halpern of Columbia University.

Following are abbreviated abstracts of the cover story article and the two related research reports, which follow each other sequentially beginning on page 840 of the issue.

Cover article (p. 840): Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LAT.
Pulsars are rapidly rotating, highly magnetized neutron stars emitting radiation across the electromagnetic spectrum. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants.

Research Report (p. 845 ): Detection of High-Energy Gamma-Ray Emission from the Globular Cluster 47 Tucanae with Fermi.
We report the detection of gamma-ray emissions above 200 megaelectron volts at a significance level of 17{sigma} from the globular cluster 47 Tucanae, using data obtained with the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. Globular clusters are expected to emit gamma rays because of the large populations of millisecond pulsars that they contain. The spectral shape of 47 Tucanae is consistent with gamma-ray emission from a population of millisecond pulsars. The observed gamma-ray luminosity implies an upper limit of 60 millisecond pulsars present in 47 Tucanae.

Research Report (p.848): A Population of Gamma-Ray Millisecond Pulsars Seen with the Fermi Large Area Telescope.
Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. We searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars (MSPs) outside of globular clusters, using rotation parameters from radio telescopes. Strong gamma-ray pulsations were detected for eight MSPs. The gamma-ray pulse profiles and spectral properties resemble those of young gamma-ray pulsars.

For more information, see:

Fermi Gamma Ray Space Telescope Stanford Web page

Fermi Gamma Ray Space Telescope NASA Web site

June/July, 2009 — Gravity Probe B Data Analysis Update

Significantly improved GP-B results from
December 2008. Both the geodetic and
frame-dragging effects are clearly visible
in the data for all 4 gyros. (Click on the
thumbnail above to view full-sized image.)

In a series of five HEPL Seminars, members of the Gravity Probe B (GP-B) science team have been detailing the progress they have made over the past three and a half years in analyzing the data from this landmark physics experiment. Four ultra-precise gyroscopes and a telescope in an earth-orbiting satellite are used to measure two effects predicted by Einstein's 1916 general theory of relativity—1) the geodetic effect (the warping of earth's local spacetime due to earth's mass) and 2) the frame-dragging effect (the twisting of earth's local spacetime due to earth's rotation).

The latest progress shows a tenfold improvement over the preliminary experimental results announced at the American Physical Society annual meeting in April 2007. At that time, only the larger, geodetic effect was clearly visible in the data. Over the past two years, the GP-B data analysis team has made significant progress in understanding and modeling three Newtonian effects, all due to patch potentials on the gyroscope rotor and housing surfaces. The latest results, based upon treatment of 1) damped polhode motion, 2) misalignment torques and 3) roll-polhode resonance torques, clearly show both frame-dragging and geodetic precession in all four gyroscopes (see figure above left).

The GP-B data analysis history reads like a detective story, with the last chapter still in-work. The data analysis described above was performed using orbit-by-orbit modeling of gyroscope orientation (97-minute intervals). The team is now developing 2-second processing of the science data, resulting in about a 3,000-fold increase in the number of data points that have to be processed.This increased computational load will be handled with parallel processing, using a computer cluster in Stanford's Aeronautics and Astronautics Department. The GP-B data analysis will conclude next spring, with final results to be announced next summer or early fall.

For more information see:

HEPL Seminar Information Page

Presentation slides from HEPL Seminars on GP-B

GP-B website

May 2009 — NASA's Fermi Telescope Measures Spectrum of Electrons and Positrons; Celebratory 'Cosmic Reflection' Concert

The Large Area Telescope (LAT) onFermi
detects gamma-rays by tracking the
electrons positrons they produce after
striking layers of tungsten. This ability also
makes the LAT an excellent tool for
exploring high-energy cosmic rays.
Credit: NASA/Goddard Space Flight Center
Conceptual Image Lab

There was much excitement at the recent American Physical Society meeting in Denver, May 2-5, 2009 about recent results from the Fermi Gamma-ray Space telescope A number of talks were given by collaboration members on many topics, including gamma-ray bursts, active galaxies, pulsars, and diffuse radiation. However, the result that received the most attention was the Fermi LAT measurement of the spectrum of electrons and positrons from 20 GeV to 1 TeV, reported on in talks by Alex Moiseev and Luca Latronico. This result received much attention, not only from the meeting attendees, but also from the science news media. An APS online Viewpoint article highlighted this important result, and Science, Nature, New Scientist, Discover Magazine, Sky and Telescope and Science News have all published stories as well.

Within hours of the cosmic-ray electron/positron result being published by Physical Review Letters, there were several new appears appearing in the online astrophysics archives offering various interpretations of these results in the context of the earlier Pamela results. These interpretations generally fell into two camps: either nearby pulsar(s) injecting primary positrons (and electrons) or dark matter decays or annihilations. The Fermi team is just beginning to understand the results, and there is much work ahead. The possibility of finding new physics cannot be ignored, and thus the theoretical physics community is eagerly anticipating more results and information from the Fermi group in the future.

The Fermi international science team, including members from Stanford and NASA, will be holding a symposium in Washington DC the first week in November 2009. On November 2, 2009, Stanford alumnus and composer, Nolan Gasser's newest composition, 'Cosmic Reflection,' will debut at the Kennedy Center for the Performing Arts as part of a free public event, celebrating the success of missions like Fermi, which explore the nature of the universe and provide possible answers to fundamental questions of physics and basic science. Gasser's composition will be performed by the Boston University Symphony. The American Brass Quintet will also be performing at the event, and there will be a short lecture about the early Fermi science results.

For more information, see:

Fermi Gamma Ray Space Telescope Stanford Web page

Fermi Gamma Ray Space Telescope NASA Web site

April 28, 2009 — Bob Byer Awarded the Frederic Ives Medal/Jarus W. Quinn Endowment by the OSA

The Frederick Ives
Medal is the highest
award bestowed by
the Optical Society
of America (OSA).

On April 28, 2009, the Optical Society of America (OSA) announced the 2009 recipients of 17 prestigious awards and medals for outstanding achievements in the field of optics. Among the recipients of this year's awards was Robert Byer, Stanford's William R. Kenan Jr. Professor of Applied Physics.

Byer was awarded the Frederic Ives Medal/Quinn Prize, the highest award bestowed by the Optical Society of America, for his pioneering contributions to optical science and the commercial development of optical technologies, and for wide-ranging leadership activities within the optics community.

"OSA is honored to recognize these leaders in the field of optics," said Elizabeth Rogan, OSA executive director. "These recipients have demonstrated tremendous ingenuity and have proved themselves to be invaluable to the understanding of optics and photonics. OSA congratulates them on their outstanding achievements."

Byer has conducted research and taught classes in lasers and nonlinear optics at Stanford since 1969. Byer will receive his award at the society's annual meeting in October in San Jose.

Fore more information see:

Bob Byer's Stanford Web Page

OSA 2009 Awards Press Release

OSA Frederick Ives Award/ Quinn Endowment Information & Past Recipients

February 19, 2009 - NASA's Fermi Telescope Sees Most Extreme Gamma-ray Blast Yet

On Sept. 17, 31.7 hours after GRB 080916C
exploded, the Gamma-Ray Burst Optical/Near-
Infrared Detector (GROND) on the 2.2m
Max Planck Telescope at the European
Southern Observatory, La Silla, Chile, began
acquiring images of the blasts fading
afterglow (circled). Credit: MPE/GROND

The first gamma-ray burst to be seen in high-resolution from NASA's Fermi Gamma-ray Space Telescope is one for the record books. The blast had the greatest total energy, the fastest motions and the highest-energy initial emissions ever seen.

"We were waiting for this one," said Peter Michelson, the principal investigator on Fermi's Large Area Telescope at Stanford University. "Burst emissions at these energies are still poorly understood, and Fermi is giving us the tools to understand them."

Gamma-ray bursts are the universe's most luminous explosions. Astronomers believe most occur when exotic massive stars run out of nuclear fuel. As a star's core collapses into a black hole, jets of material -- powered by processes not yet fully understood -- blast outward at nearly the speed of light. The jets bore all the way through the collapsing star and continue into space, where they interact with gas previously shed by the star and generate bright afterglows that fade with time.

This explosion, designated GRB 080916C, occurred at 7:13 p.m. EDT on Sept. 15, in the constellation Carina. Fermi's other instrument, the Gamma-ray Burst Monitor, simultaneously recorded the event. Together, the two instruments provide a view of the blast's initial, or prompt, gamma-ray emission from energies between 3,000 to more than 5 billion times that of visible light.

NASA provides a movie that compresses about 8 minutes of Fermi LAT observations of GRB 080916C into 6 seconds. Colored dots represent gamma rays of different energies. Visible light has energy between about 2 and 3 electron volts (eV). The blue dots represent lower-energy gamma rays (less than 100 million eV); green, moderate energies (100 million to 1 billion eV); and red, the highest energies (more than 1 billion eV). Credit: NASA/DOE/Fermi LAT Collaboration.

View video at: http://www.nasa.gov/mov/314162main_GRB080916C_LAT_600.mov.

For more information, see:

Fermi Gamma Ray Space Telescope Stanford Web page

Fermi Gamma Ray Space Telescope NASA Web site

January 5, 2009 - CDMS Leading the Search for Dark Matter in the Form of WIMPs

Project manager Dan Bauer from Fermilab
holds one tower of detectors as Vuk Mandic,
now at the University of Minnesota, examines
them. (Photo courtesy of Fermilab)

In the January 13, 2009 issue of Physical Review Letters, the CDMS (Cryogenic Dark Matter Search) Collaboration has published the latest results from its search for WIMPs (weakly interactive massive particles). These elusive particles are curently favored as the essence of dark matter, which scientists believe accounts for 83% of all matter in the universe. Data for this experiment was collected at the Soudan Underground Laboratory (CDMS II), located 2,400 ft undergournd in the Soudan Mine in Minnesota, using an arragy of five detector towers, each containing a vertical stack of six solid-state detector discs, cooled with liquid helium to a cryogenic temperature of ~40 mK. The results from this experiment have achieved the best sensitivity to date for dark matter WIMPs with masses above 4 GeV/c² and have set new upper limits on the spin-independent interaction of WIMPs and nucleons. Full Story...

January 7, 2009 - Fermi Gamma Ray Space Telescope Discovers Slew of New Pulsars

by Kelen Tuttle, SLAC Today

The Fermi Telescope has found 12 previously unknown
pulsars (orange). It also detected gamma-ray emissions
from known radio pulsars (magenta, cyan) and from known
or suspected gamma-ray pulsars (green). (Image courtesy
of NASA/Fermi/LAT Collaboration.)

Four months into its mission, the Fermi Gamma-ray Space Telescope has discovered 12 never-before-seen pulsars and observed gamma-ray pulses from 18 others, shedding new insight on the high-energy universe.

"I am very happy to welcome you all to a new era in pulsar physics," Roger Romani said at a press conference held yesterday at the American Astronomical Society meeting in Long Beach, California. Romani is a researcher in the Kavli Institute for Particle Astrophysics and Cosmology at SLAC National Accelerator Laboratory and Stanford University. "We know of 1800 pulsars, but until Fermi we saw only little wisps of energy from all but a handful of them. Now, for dozens of pulsars, we're seeing the actual power of these machines."

In the past, most pulsars–rapidly spinning neutron stars that emit energy in narrow beams–were observed only in radio waves. Yet, as the FGST data reveals, this radio-wave emission is extremely weak compared to the pulsars' flashes of gamma-rays.

The 12 newly discovered pulsars offer insight into the mechanism behind the gamma-ray emissions. The data show that the classic understanding of emission, whereby gamma rays are created in the same location as radio waves, is mistaken. Researchers now theorize that the radio beams form near the neutron star's surface, while the gamma rays form far above.

FGST is also shedding light on pulsars as they near the end of their lifecycles. Over the past few months, the telescope found seven very old and relatively rare pulsars that are thought to have gravitationally attracted additional stellar matter from companion stars, causing them to increase in mass and spin much faster. These "millisecond" pulsars spin hundreds of times faster than their younger siblings, with their surfaces moving at up to a tenth of the speed of light. They also have magnetic fields 10,000 times lower and are thought to be 10,000 times older than previously discovered pulsars.

With the observation of these millisecond pulsars, Romani said, "we're really seeing the history of pulsars." Alice Harding of the NASA-Goddard Space Flight Center added: "This is the tip-of-the-iceberg. We'll probably be discovering a lot more."

Researchers announced these findings at the American Astronomical Society meeting this week in Long Beach, California, and at the Texas Symposium on Relativistic Astrophysics last December in Vancouver, Canada. More information can be found in a NASA press release issued yesterday and in a recent Science News article by Ron Cowen.

For more information, see:

Fermi Gamma Ray Space Telescope Stanford Web page

Fermi Gamma Ray Space Telescope NASA Web site

August 26, 2008 - GLAST Observatory Renamed for Fermi, Reveals Entire Gamma-Ray Sky

The U.S. Department of Energy (DOE) and NASA announced today that the Gamma-Ray Large Area Space Telescope (GLAST) has revealed its first all-sky map in gamma rays. The onboard Large Area Telescope's (LAT) all-sky image—which shows the glowing gas of the Milky Way, blinking pulsars and a flaring galaxy billions of light-years away—was created using only 95 hours of "first light" observations, compared with past missions which took years to produce a similar image. Scientists expect the telescope will discover many new pulsars in our own galaxy, reveal powerful processes near super-massive black holes at the cores of thousands of active galaxies and enable a search for signs of new physical laws.

The NASA mission was made possible by collaboration with many U.S. and international partners. As part of its support for particle physics research, DOE contributed funding to the LAT—the primary instrument on GLAST—and DOE's Stanford Linear Accelerator Center (SLAC) managed the LAT construction. SLAC also played a key role in assembling the instrument and now plays the central role in LAT science operations, data processing and making scientific data available to collaborators for analysis.

"The DOE-NASA collaboration on this new observatory has been very successful and shows what can be accomplished when we work together," said Dennis Kovar, DOE Associate Director of Science for High Energy Physics. "We look forward to the scientific discoveries it will enable in both particle physics and astrophysics."

NASA also announced today that GLAST has been renamed the Fermi Gamma-ray Space Telescope. The new name honors Prof. Enrico Fermi (1901-1954), a pioneer in high-energy physics. "Enrico Fermi was the first person to suggest how cosmic particles could be accelerated to high speeds," said Paul Hertz, chief scientist for the Science Mission Directorate at NASA Headquarters in Washington, D.C. "His theory provides the foundation for understanding the powerful phenomena his namesake telescope will discover."

For two months following the mission's June 11, 2008 launch, scientists tested and calibrated its two instruments, the LAT and the GLAST Burst Monitor (GBM). "What impressed me the most is that everything went by the book," said Peter Michelson, LAT principal investigator at Stanford University, Calif. "We're elated." The LAT has already verified sources found by other gamma-ray detectors—and discovered more.

The all-sky image shows gas and dust in the plane of the Milky Way glowing in gamma rays due to collisions with accelerated nuclei called cosmic rays. The famous Crab Nebula and Vela pulsars also shine brightly at these wavelengths. These fast-spinning neutron stars, which form when massive stars die, were originally discovered by their radio emissions. The image's third pulsar, named Geminga and located in Gemini, is not a radio source. It was discovered by an earlier gamma-ray satellite. The Fermi Gamma-ray Space Telescope is expected to discover many more radio-quiet pulsars, providing key information about how these exotic objects work.

A fourth bright spot in the LAT image lies some 7.1 billion light-years away, far beyond our galaxy. This is 3C 454.3 in Pegasus, a type of active galaxy called a blazar. It's now undergoing a flaring episode that makes it especially bright.

The LAT scans the entire sky every three hours when operating in survey mode, which will occupy most of the telescope's observing time during the first year of operations. These fast snapshots will let scientists monitor rapidly changing sources.

The LAT instrument detects photons with energies ranging from 20 million electronvolts to over 300 billion electronvolts. The high end of this range, which corresponds to energies more than 5 million times greater than dental X-rays, is little explored.

The spacecraft's secondary instrument, the GBM, spotted 31 gamma-ray bursts in its first month of operation. These high-energy blasts occur when massive stars die and when orbiting neutron stars spiral together and merge.

The GBM is sensitive to lower energy range gamma rays (8000 to 30 million electronvolts) than LAT. Bursts seen by both instruments will provide an unprecedented look across a broad gamma-ray spectrum, enabling scientists to peer into the processes powering these events.

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

Date Issued: August 26, 2008 (SLAC Today)

Contact:

• David Harris, Stanford Linear Accelerator Center: 1 (650) 926-8580, david.harris@slac.stanford.edu
• Jeff Sherwood, Department of Energy: 1 (202) 586-5806, jeff.sherwood@hq.doe.gov
• J.D. Harrington, NASA: 1 (202) 358-5241, j.d.harrington@nasa.gov

Relevant Web URLs:

• Stanford Linear Accelerator Center
• NASA

August 2008 - Palanker Research Group Develops Pulsed Electron Avalanche Knife (PEAK)

Discharge on cylindrical microelectrode in
saline driven by microsecond burst of pulses.

Daniel Palanker's research group at HEPL and the Stanford Medical School have developed electrosurgical technology called Pulsed Electron Avalanche Knife (PEAK). Stanford's Office of Technology Licensing licensed it to a local startup company called PEAK Surgical Inc. They recently received FDA approval for this device, and performed their first 30-40 human cases during the last couple weeks. Feedback from surgeons is exceptionally good, so this device has a potential to become a new standard of care in surgery. In contrast to conventional electrosurgery, based on continuous radiofrequency waveforms applied via large electrodes, PEAK uses microsecond pulses and micrometers-thin blade electrodes to excise tissue with cellular precision. Not only the cuts are more precise and narrow, but also, due to the very low collateral thermal damage produced by PEAK technology, the tissue heals faster, and with much less scarring and other defects, than after traditional electrosurgery.

For more information see:

Palanker Lab Web site

Stanford School of Medicine—Opthamology Research Web site

ROBERT L. BYER, HEPL faculty member, professor of applied physics and director of the Ginzton Laboratory, has won the 2009 IEEE Photonics Award. Byer, the William R. Kenan Jr. Professor, was cited for "seminal contributions to nonlinear optics and solid-state lasers for commercial applications
from precision measurement to manufacturing." The products of non-linear optics, which often involve changing the color of lasers, have wide use. For example, the yellow laser that creates an artificial star 90 kilometers above Earth is used by astronomers to calibrate their telescopes, to eliminate blurring from the atmosphere. Laser televisions, another product of multi-colored lasers, are expected to hit the market soon. Solid-state lasers have a wide range of uses, including trimming and processing the circuit boards in cell phones.

Jul 2008

image courtesy of NASA

GLAST Launches Into Space

The GLAST mission begins with a thunderous liftoff.

NASA's GLAST Launch Successful

Crystal bells stay silent as physicists look for dark matter

U.S. experiment retakes the lead in competitive race

Batavia, Ill.--Scientists of the Cryogenic Dark Matter Search experiment today announced that they have regained the lead in the worldwide race to find the particles that make up dark matter. The CDMS experiment, conducted a half-mile underground in a mine in Soudan, Minn., again sets the world’s best constraints on the properties of dark matter candidates.

“With our new result we are leapfrogging the competition,” said Blas Cabrera of Stanford University, co-spokesperson of the CDMS experiment, for which the Department of Energy’s Fermi National Accelerator Laboratory hosts the project management. “We have achieved the world’s most stringent limits on how often dark matter particles interact with ordinary matter and how heavy they are, in particular in the theoretically favored mass range of more than 40 times the proton mass. Our experiment is now sensitive enough to hear WIMPs even if they ring the ‘bells’ of our crystal germanium detector only twice a year. So far, we have heard nothing.”

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