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


Protons hog the momentum in neutron-rich nuclei
Like dancers swirling on the dance floor with bystanders looking on, protons and neutrons that have briefly paired up in the nucleus have higher-average momentum, leaving less for non-paired nucleons.

NuSTAR Discovers Impossibly Bright Dead Star
Astronomers working with NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), led by Caltech's Fiona Harrison, have found a pulsating dead star beaming with the energy of about 10 million suns.

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.
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!

neutron Star

neutron Star
by Niven Larry (Author)


March 1978 8th US printing Ballantine 27065 mass market paperback as shown. Appears never completely opened. Tight spine, tanned pages, no writing, no tears, appears spine's slight overlap is from production run rather than a crease, smokefree.

Neutron Star

Neutron Star
by Larry Niven (Author)




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


Jack finally has a job he can hold down. That's the plus side. The minus side is that it involves him entering worm-holes, traversing strange solar systems to find rare resources. Not so bad? Not usually, but this time he has entered a realm few have seen.
And it houses the densest object in the cosmos.
A Neutron Star.
With only a one-eyed robot as company, can Jack resist the star-remnant's irresistible pull?
...Or will it send him mad?

Neutron Stars and Pulsars

Neutron Stars and Pulsars
by Pennyhill Press


Were it not for neutron stars neither we, nor the earth, nor any other planets would exist. Why do stars—so small that we cannot see them as we see other stars in the night sky—play such a singular role in the cosmic scheme? That is the story I tell.

The first neutron star was discovered quite by chance by Jocelyn Bell (Burnett) using a primitive antenna consisting of wires strung on stakes in a pasture near Cambridge University. With this antenna a faint but regular signal was detected—day after day. At first the team of researchers wondered if “little green men” from outer space were trying to contact earthlings. But Jocelyn Bell and Anthony Hewish soon realized they had stumbled onto a strange but natural phenomenon—a very small star about 10 kilometers in...

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.

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.

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.

Astrophysics of Neutron Stars (Astronomy and Astrophysics Library)

Astrophysics of Neutron Stars (Astronomy and Astrophysics Library)
by Vladimir M. Lipunov (Author), G. Börner (Editor), R.S. Wadhwa (Editor)


Here the reader will find a description of the current state of experimentaland theoretical investigations of neutron stars in all their manifestations:radio pulsars, X-ray pul- sars, X-ray bursters, transient X-ray sources, andso on. The approach adopted stresses the idea that the astrophysi- cal properties of a neutron star are determinated mainly by its interaction withits surroundings, that is, the inter- action of the intense intrinsic magnetic field of the neutron star with an accreting plasma. Thus the book also treats topics in plasma physics and magnetohydrodynamics. Students and professionals in astrophysics and physics alike will find this revised and enlarged version of the original Russian edition essential reading for its coverage of neutron star classification and...

© 2014 BrightSurf.com