The bursts are from "magnetars," some of the most enigmatic objects in the universe.
Magnetars are a type of neutron star, which are superdense stars that pack the mass of a sun into a body the size of Manhattan Island. Tiny magnetars possess magnetic fields that are at least 100 trillion times as powerful as Earth's magnetic field. They occasionally produce powerful bursts, hurling high-energy radiation cascading across space. The origin of these energetic eruptions and the strong magnetic fields is a mystery.
Astronomers discovered a magnetar with NASA's X-Ray Timing Explorer in July 2003, when it brightened by about 100 times its usual faint luminosity. They continued monitoring it regularly with the European Photon Imaging Camera, known as EPIC, on the European Space Agency's XMM-Newton Observatory until March 2006, when the object faded to its pre-outburst brightness.
As the magnetar faded, EPIC recorded changes in the energies of the X-rays released.
Tolga Guver, who is a visiting graduate student at the UA, working with Assistant Professor Feryal Ozel of the UA physics and UA astronomy departments, compared the magnetar's changing X-ray spectrum with predictions from a computer model. They developed the model to describe the physical properties of a magnetar's surface and magnetic field in detail.
Guver, Ozel and their collaborators found that the data was best fitted with a model that traced the outburst to just below the surface of the magnetar and confined it to an area about 3.5 kilometers (about two miles) across.
"This is the first time both the surface emission and its subsequent reprocessing in the magnetosphere have been incorporated into the same computer model," Ozel said.
"This is a breakthrough because we can now distinguish between surface and magnetospheric phenomena,'' Guver said.
Determining both the size and the location of the powerful burst is like "performing anatomy on a distant, tiny star,'' Ozel added.
Their model also allowed Guver, Ozel and their colleagues to determine spectroscopically the strength of this object's magnetic field. The magnetar's magnetic field is around 600 trillion times stronger than the Earth's magnetic field.The scientists say they are encouraged because the measurement is similar to an earlier estimate made based on how fast the source is "spinning down,"
which is the change in the spin period over time. They said it boosts their confidence that their model is correct.
"It is tremendously exciting to be able to compute exotic quantum phenomena that appear only in these ultrastrong magnetic fields and to see these predictions appear in actual data,'' Ozel added.
The astronomers say that they don't yet understand the mechanism of the outburst, which is probably somehow magnetically triggered.
The researchers say they plan to use their computer model to study more magnetars, using more data from X-ray observatories, in the quest for answers.
They are publishing their results in today's edition (Sept. 20, 2007) of the Astrophysical Journal Letters. The paper's authors are Guver, Ozel, Ersin Gogus of Sabanci University, Istanbul, Turkey, and Chryssa Kouveliotou of the NASA Marshall Space Flight Center, Huntsville, Ala.CONTACTS: Feryal Ozel (520-626-1622; email@example.com
Lori Stiles | University of Arizona
A Keen Sense for Molecules
23.02.2018 | Max-Planck-Institut für Quantenoptik
Good vibrations feel the force
23.02.2018 | Max-Planck-Institut für Struktur und Dynamik der Materie
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Trade Fair News
23.02.2018 | Life Sciences