Science Current Events | Science News | Brightsurf.com
 

Crab Pulsar emits light at highest energies ever detected in a pulsar system, scientists report

October 07, 2011
An international team of scientists has detected the highest energy gamma rays ever observed from a pulsar, a highly magnetized and rapidly spinning neutron star.

The VERITAS experiment measured gamma rays coming from the Crab Pulsar at such large energies that they cannot be explained by current scientific models of how pulsars behave, the researchers said.

The results, published today in the journal Science, outline the first observation of photons from a pulsar system with energies greater than 100 billion electron volts -- more than 50 billion times higher than visible light from the sun.

"This is the highest energy pulsar system ever detected," said Rene Ong, a UCLA professor of physics and astronomy and spokesperson for the VERITAS collaboration. "It is a completely new and surprising phenomenon for pulsars."

Data were acquired for 107 hours over the course of three years by VERITAS's ground-based gamma ray observatory, which is part of southern Arizona's Whipple Observatory, a facility managed by the Harvard-Smithsonian Center for Astrophysics. VERITAS (Very Energetic Radiation Imaging Telescope Array System) observes gamma rays using a network of four telescopes, each 12 meters in diameter.

Ong noted that all previous observations of pulsars indicated that the radiation cuts off at the high energies the team observed.

"It means the radiation we detect must be a new component that was completely unexpected," he said.

Gamma rays, the most energetic type of electromagnetic radiation, cannot be directed by lenses or bounced off mirrors like ordinary visible light, Ong said. Because the rays are invisible to the human eye, the only way telescopes on Earth can detect them is by observing the path they take as they are absorbed in the planet's atmosphere.

Gamma rays are ejected from the Crab Pulsar, and they smash into Earth's atmosphere, causing "the electromagnetic equivalent of a sonic boom," Ong said. This collision creates a shower of visible light more than 6 miles above the ground that is recorded by VERITAS.

"The atmosphere is an integral part of our measurement system, which makes VERITAS different from conventional telescopes," Ong said.

One of the most widely studied astronomical objects in the northern hemisphere, the Crab Nebula, which is some 6,500 light-years from Earth, was formed when a massive star exploded in a supernova event that was observed on Earth in the year 1054. While it is most typical for pulsars to be ejected from the stellar wreckage during a supernova, in the case of the Crab system, the pulsar remained at its center, producing radiation that covers the entire electromagnetic spectrum, Ong said.

He calls the Crab system the "Rosetta Stone of astronomy," because astronomers and astrophysicists have observed this object at every conceivable wavelength of light.

"The Crab Pulsar is considered among the best understood systems in all of astronomy, yet here we have found something totally new," he said. "It is astronomy in a completely new light; we are seeing phenomena that you just can't explore with optical light or X-rays, or even low-energy gamma rays."

The Crab Pulsar is a highly magnetized neutron star with a surface magnetic field a trillion times stronger than that of the Earth. The star spins at the dizzying rate of about 30 times a second and emits gamma rays through "curvature radiation," an effect that creates a lighthouse-like beacon that winks on when the beam faces the Earth and off when the star pivots away.

Light detected by the VERITAS experiment cannot be explained by curvature radiation, however, and likely comes from regions well outside the high-magnetic field region close to the neutron star, Ong said. While such energetic gamma rays have been observed elsewhere in the galaxy, the actual mechanism of how they are created in a pulsar is not fully understood.

"The pulse duration of the radiation we see is almost three times shorter than that seen at other gamma ray energies," he said. "This was very surprising and means this new radiation is probably coming from a different physical region of the star's outer magnetosphere."

The VERITAS experiment looks for radiation emanating from celestial objects such as pulsars, active galaxies, the center of the Milky Way and supermassive black holes. It has collected data for nearly 1,000 hours every year since it began operating in 2007.

"We are trying to understand processes out in the cosmos that can create particles at these extreme energies, beyond what can be produced here on Earth," Ong said. "We are also very interested in seeing if these processes indicate some sort of new physics."

Ong hopes his research may shed some light on the mystery of cosmic rays.

"We are bombarded by high-energy particles from all over the cosmos that reach unimaginable energies," he said. "These cosmic rays are an important energy source in our galaxy, yet we have no clue where they are coming from.

"This measurement indirectly gives us clues to the highest energies in the cosmos, telling us about particles and energies that we can't generate here on Earth but that nature's accelerators are able to create for us."

Ong is currently helping to plan the next-generation ground-based gamma ray observatory, called the Cherenkov Telescope Array (CTA). Covering more than one-half square mile with dozens of telescopes, the CTA will be 10 times more sensitive than VERITAS, allowing radiation from fainter and more distant objects to be accurately resolved.

###

The 95 co-authors of the Science paper on the Crab Pulsar include scientists from 26 institutions in five countries who are part of the VERITAS collaboration. UCLA co-authors include Vladimir Vassiliev, an associate professor of physics and astronomy; Pratik Majumdar, a postdoctoral scholar in physics and astronomy; and Timothy Arlen, a graduate student.

This research is supported by the U.S. Department of Energy, the U.S. National Science Foundation, the Smithsonian Institution, the National Sciences and Engineering Research Council of Canada, the U.K.'s Science and Technology Facilities Council, and the Science Foundation Ireland.

UCLA is California's largest university, with an enrollment of nearly 38,000 undergraduate and graduate students. The UCLA College of Letters and Science and the university's 11 professional schools feature renowned faculty and offer 337 degree programs and majors. UCLA is a national and international leader in the breadth and quality of its academic, research, health care, cultural, continuing education and athletic programs. Six alumni and five faculty have been awarded the Nobel Prize.

University of California - Los Angeles


Related Neutron Star Current Events and Neutron Star News Articles


Watching for a black hole to gobble up a gas cloud
Right now a doomed gas cloud is edging ever closer to the supermassive black hole at the center of our Milky Way galaxy. These black holes feed on gas and dust all the time, but astronomers rarely get to see mealtime in action.

Simple, like a neutron star
In how many ways can one describe an object? Take an apple: by just looking at it we can easily estimate its weight, shape and colour but we are unable to describe it at any other level, for example, to evaluate the chemical composition of its flesh.

Milky Way may have formed 'inside-out': Gaia provides new insight into Galactic evolution
A breakthrough using data from the Gaia-ESO project has provided evidence backing up theoretically predicted divisions in the chemical composition of the stars that make up the Milky Way's disc - the vast collection of giant gas clouds and billions of stars that give our Galaxy its 'flying saucer' shape.

Space station MAXI-mizing our understanding of the universe
Look up at the night sky ... do you see it? The stars of the cosmos bursting in magnificent explosions of death and rebirth! No? Well, then maybe you are not looking through the "eyes" of the Monitor of All-sky X-ray Image (MAXI) investigation, mounted on the exterior of the International Space Station Kibo module.

Pulsar in stellar triple system makes unique gravitational laboratory
Astronomers using the National Science Foundation's Green Bank Telescope (GBT) have discovered a unique stellar system of two white dwarf stars and a superdense neutron star, all packed within a space smaller than Earth's orbit around the Sun.

Newly discovered three-star system could debunk Einstein's theory of General Relativity
A newly discovered system of two white dwarf stars and a superdense pulsar-all packed within a space smaller than the Earth's orbit around the sun-is enabling astronomers to probe a range of cosmic mysteries, including the very nature of gravity itself.

Powerful ancient explosions explain new class of supernovae
Astronomers affiliated with the Supernova Legacy Survey (SNLS) have discovered two of the brightest and most distant supernovae ever recorded, 10 billion light-years away and a hundred times more luminous than a normal supernova. Their findings appear in the Dec. 20 issue of the Astrophysical Journal.

A Blast from Its Past Dates the Youngest Neutron-Star Binary
X-rays streaming toward Earth from the region near a neutron star that is cannibalizing its companion star have revealed the pair to be the youngest "X-ray binary" yet known.

Fledgling supernova remnant reveals neutron star's secrets
With the help of NASA's Chandra X-ray Observatory and the Australia Telescope Compact Array, an international team of astronomers has identified the glowing wreck of a star that exploded a mere 2,500 years ago - the blink of an eye in astronomical terms.

Supernova Blast Provides Clues to Age of Binary Star System
Data from NASA's Chandra X-ray Observatory has revealed faint remnants of a supernova explosion and helped researchers determine Circinus X-1 -- an X-ray binary -- is the youngest of this class of astronomical objects found to date.
More Neutron Star Current Events and Neutron Star News Articles

Neutron Star

Neutron Star
by Larry Niven (Author)


Come to Larry Niven's Universe and meet all the natives: Thrints, Bandersnatchi, Puppeteers -- and a host of other wonderfully created characters.
Visit Lookitthat, Down, and Jinx -- indeed, an entire galaxy of planets found only in these stories that trace man's expansion and colonization throughout Known Space.
A spectacular cycle of the future . . . a 10,000-year history of man on Earth and in space!

Star One: Neutron Star

Star One: Neutron Star
by Raymond L. Weil


Edited by Frank MacDonald 08-28-2013

It is the year 2044 on Earth. At the Farside observatory complex on the Moon, a startling astronomical discovery has been made. A survey for pulsars has found an x-ray source in a region of space where none has been detected before.

Upon further investigation, they find that this x-ray source is just outside of the Solar System. The astronomers are paralyzed by what they have found knowing what its disastrous ramifications might be.

A neutron star is approaching the Solar System. It appeared out of a small dust cloud that was shielding its approach. Armageddon has arrived; the star is on a trajectory that will take it through the center of the Solar System. Life on Earth will not survive its passing.

The...

Black Holes, White Dwarfs and Neutron Stars: The Physics of Compact Objects

Black Holes, White Dwarfs and Neutron Stars: The Physics of Compact Objects
by Stuart L. Shapiro (Author), Saul A. Teukolsky (Author)


This self-contained textbook brings together many different branches of physics--e.g. nuclear physics, solid state physics, particle physics, hydrodynamics, relativity--to analyze compact objects. The latest astronomical data is assessed. Over 250 exercises.

Neutron Star

Neutron Star
by Larry Niven (Author)




Star One: Dark Star

Star One: Dark Star



The FarQuest has been launched on her mission of discovery to the approaching neutron star. On Earth, unrest is quickly growing as people realize that life on Earth might shortly come to an abrupt end.

President Kateland is doing everything in her power to try to preserve at least a small portion of the human race. However, a powerful U.S. Senator does not believe the neutron star threat is real.

The situation on Earth is about to explode as Star One and Tycho City struggle to survive in an uncertain future. What is even more frightening is the dark secret hidden by the neutron star. A secret that is so deadly that it makes any chance of survival seem almost impossible.

This is the exciting conclusion to Star One: Neutron Star.

Ringworld

Ringworld
by Larry Niven (Author)


A new place is being built, a world of huge dimensions, encompassing millions of miles, stronger than any planet before it. There is gravity, and with high walls and its proximity to the sun, a livable new planet that is three million times the area of the Earth can be formed. We can start again!

Death of a Neutron Star (Star Trek Voyager, No 17)

Death of a Neutron Star (Star Trek Voyager, No 17)
by Eric Kotani (Author)


An alien scientist asks to join Captain Kathryn Janeway in the investigation of an unprecedented scientific find. Soon Voyager is embroiled in a battle of wills among several alien races -- each intent on decimating whole worlds in the process.

Life and Death of the Stars (Undergraduate Lecture Notes in Physics)

Life and Death of the Stars (Undergraduate Lecture Notes in Physics)
by Ganesan Srinivasan (Author)


This volume is devoted to one of the fascinating things about stars: how they evolve as they age. This evolution is different for stars of different masses. How stars end their lives when their supply of energy is exhausted also depends on their masses. Interestingly, astronomers conjectured about the ultimate fate of the stars even before the details of their evolution became clear. Part I of this book gives an account of the remarkable predictions made during the 1920s and 1930s concerning the ultimate fate of stars. Since much of this development hinged on quantum physics that emerged during this time, a detailed introduction to the relevant physics is included in the book. Part II is a summary of the life history of stars. This discussion is divided into three parts: low-mass stars,...

Star Trek: The Original Series: No Time Like the Past

Star Trek: The Original Series: No Time Like the Past
by Greg Cox (Author)


STARDATE 6122.5. A diplomatic mission to the planet Yusub erupts in violence when ruthless Orion raiders attempt to disrupt the crucial negotiations by force. Caught in the midst of a tense and dangerous situation, Captain James T. Kirk of the U.S.S. Enterprise finds an unexpected ally in the form of an enigmatic stranger who calls herself “Annika Seven.”

STARDATE 53786.1. Seven of Nine is taking part in an archae­ological expedition on an obscure planetoid in the Delta Quadrant when a disastrous turn of events puts Voyager’s away team in jeopardy—and transports Seven across time and space to Yusub, where she comes face-to-face with one of Starfleet’s greatest legends.

STARDATE 6122.5. Kirk knows better than most the danger that even a single castaway from the...

Three Books of Known Space

Three Books of Known Space
by Larry Niven (Author)


Let three complete books in one take you on a dazzling journey into science fiction's most famous future history: Known Space!
WORLD OF PTAVVS
Kzanol was a thrint from a distant galaxy. He had been trapped on Earth in a time-stasis field for two billion years. Now he was on the loose, and telepath Larry Greenberg knew everything he was thinking. Thrints lived to plunder and enslave lesser planets . . . and the planet Kzanol had in mind was Earth!
A GIFT FROM EARTH
Shrouded in lethal mists, the world named Mount Lookitthat was never meant for humans. Life existed only on one plateau, unreachable except from space. But still the planet had been colonized, and the settlers struggled to survive under a ruthless dictatorship on a rebellion-proof world . . . until fate dealt them a...

© 2014 BrightSurf.com