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


NASA's RXTE Satellite Decodes the Rhythm of an Unusual Black Hole
Astronomers have uncovered rhythmic pulsations from a rare type of black hole 12 million light-years away by sifting through archival data from NASA's Rossi X-ray Timing Explorer (RXTE) satellite.

Fascinating rhythm: light pulses illuminate a rare black hole
The universe has so many black holes that it's impossible to count them all. There may be 100 million of these intriguing astral objects in our galaxy alone.

White dwarfs crashing into neutron stars explain loneliest supernovae
A research team led by astronomers and astrophysicists at the University of Warwick have found that some of the Universe's loneliest supernovae are likely created by the collisions of white dwarf stars into neutron stars.

NASA's Fermi Finds A 'Transformer' Pulsar
In late June 2013, an exceptional binary containing a rapidly spinning neutron star underwent a dramatic change in behavior never before observed. The pulsar's radio beacon vanished, while at the same time the system brightened fivefold in gamma rays, the most powerful form of light, according to measurements by NASA's Fermi Gamma-ray Space Telescope.

Astronomers discover first Thorne-Zytkow object, a bizarre type of hybrid star
In a discovery decades in the making, scientists have detected the first of a "theoretical" class of stars first proposed in 1975 by physicist Kip Thorne and astronomer Anna Żytkow.

Stability lost as supernovae explode
Exploding supernovae are a phenomenon that is still not fully understood.

Magnetar formation mystery solved?
When a massive star collapses under its own gravity during a supernova explosion it forms either a neutron star or black hole.

Neutron star magnetic fields: not so turbulent?
Neutron stars, the extraordinarily dense stellar bodies created when massive stars collapse, are known to host the strongest magnetic fields in the universe -- as much as a billion times more powerful than any man-made electromagnet.

Astronomers harness the galaxy's biggest telescope to make most precise measurement of spinning star
An international team of astronomers has made a measurement of a distant neutron star that is one million times more precise than the previous world's best.

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.
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...

Neutron Star

Neutron Star
by Larry Niven (Author)




Conquering the Physics GRE

Conquering the Physics GRE
by Yoni Kahn (Author), Adam Anderson (Author)


Thousands of students take the GRE subject test in physics each year, yet surprisingly few published resources exist to help students prepare for the content and structure of this important exam. This book, written by two MIT graduate students intimately familiar with the content of the exam, is a comprehensive review of all topics covered on the Physics GRE. Conquering the Physics GRE includes three full-length practice tests with worked solutions, content reviews of all the major subject areas with over 150 additional problems, and a full chapter on special test-taking tips specific to the Physics GRE. This revised and edited second edition extends the discussions in the subject area reviews, contains several new diagrams and problems, and features updated sample exams whose questions...

Special and General Relativity: With Applications to White Dwarfs, Neutron Stars and Black Holes (Astronomy and Astrophysics Library)

Special and General Relativity: With Applications to White Dwarfs, Neutron Stars and Black Holes (Astronomy and Astrophysics Library)
by Norman K. Glendenning (Author)


Special and General Relativity are concisely developed together with essential aspects of nuclear and particle physics. Problem sets are provided for many chapters, making the book ideal for a course on the physics of white dwarf and neutron star interiors. Norman K. Glendenning is Senior Scientist Emeritus at the Nuclear Science Division, Institute for Nuclear and Particle Astrophysics, Lawrence Berkeley National Laboratory at the University of California, Berkeley. He is the author of numerous books.

The Fabric of the Cosmos: Space, Time, and the Texture of Reality

The Fabric of the Cosmos: Space, Time, and the Texture of Reality
by Brian Greene (Author)


From Brian Greene, one of the world’s leading physicists and author the Pulitzer Prize finalist The Elegant Universe, comes a grand tour of the universe that makes us look at reality in a completely different way.

Space and time form the very fabric of the cosmos. Yet they remain among the most mysterious of concepts. Is space an entity? Why does time have a direction? Could the universe exist without space and time? Can we travel to the past? Greene has set himself a daunting task: to explain non-intuitive, mathematical concepts like String Theory, the Heisenberg Uncertainty Principle, and Inflationary Cosmology with analogies drawn from common experience. From Newton’s unchanging realm in which space and time are absolute, to Einstein’s fluid conception of...

What If?: Serious Scientific Answers to Absurd Hypothetical Questions

What If?: Serious Scientific Answers to Absurd Hypothetical Questions
by Randall Munroe (Author)


From the creator of the wildly popular webcomic xkcd, hilarious and informative answers to important questions you probably never thought to ask. Millions of people visit xkcd.com each week to read Randall Munroe’s iconic webcomic. His stick-figure drawings about science, technology, language, and love have a large and passionate following. Fans of xkcd ask Munroe a lot of strange questions. What if you tried to hit a baseball pitched at 90 percent the speed of light? How fast can you hit a speed bump while driving and live? If there was a robot apocalypse, how long would humanity last? In pursuit of answers, Munroe runs computer simulations, pores over stacks of declassified military research memos, solves differential equations, and consults with nuclear reactor operators. His...

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.

Stars and Galaxies

Stars and Galaxies
by Michael A. Seeds (Author), Dana Backman (Author)


With this newly revised Eighth Edition of STARS AND GALAXIES, the authors' goals are to help you use astronomy to understand science--and use science to understand what we are. Fascinating, engaging, and visually vibrant, this text will help you answer two fundamental questions: What are we? And how do we know?

Star Trek: Neutron Stars, Antimatter, and Other Topics in Physics

Star Trek: Neutron Stars, Antimatter, and Other Topics in Physics


This work explores the physics behind concepts covered in Star Trek: The Next Generation episodes.

The vastness of space and our sheer curiosity of the unknown drive us to understand more about the universe, to seek answers to age old questions, and to explore.

From magical eddies of space plasmas to particles with unknown properties and mysterious solar events, this book takes on all horizons of known physics and gives the reader simple explanations of amazing phenomena.

© 2014 BrightSurf.com