HEAPOW: Taking the Pulse of the Dead (2014 Sep 22)

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HEAPOW: Taking the Pulse of the Dead (2014 Sep 22)

Physicists use particle accelerators, or "atom-smashers" to understand nature on the smallest scales. But natural particle accelerators can be many times more powerful than the most powerful accelerator ever built on earth. The locations of these cosmic accelerators have been identified by so-called tera-electron volt observatories, like H.E.S.S., VERITAS and MAGIC. These telescopes work by detecting the effects of enormously energetic photons produced by these extraordinary cosmic accelerators on the very atmosphere of the Earth. These telescopes, along with the Fermi Gamma-ray Space Telescope, has helped detect sites of high energy particle acceleration. Many of these sources have been identified as being associated with pulsars, rapidly spinning neutron stars, the dead remnants of exploded stars. But some of these sources remain a mystery. Now, thanks to the NuSTAR space observatory, one mystery has been resolved. This mysterious object, known as HESS J1640-465, was identified as a source of very high energy gamma-ray radiation. This source was associated with a supernova remnant, as shown in the composite radio and infrared image above, but the connection between this TEV source and the supernova remnant was not clear. Observations with the XMM-Newton and Chandra X-ray Observatory hinted that the source was possibly a powerful neutron star. But the final nail in the coffin, so to speak, was provided by NuSTAR. NuSTAR, with its capabiity to make images at energies eight times higher than either Chandra or XMM, was able to peer through the murk in front of the H.E.S.S. source, and to reveal the pulsar at its heart.

HESS J1640−465 – an exceptionally luminous TeV gamma-ray supernova remnant

HESS J1640-465 - an exceptionally luminous TeV gamma-ray supernova remnant - H.E.S.S. Collaboration

• Monthly Notices of the RAS 439(3) 2828 (2014 Apr 11) DOI: 10.1093/mnras/stu139
  arXiv.org > astro-ph > arXiv:1401.4388 > 17 Jan 2014 (v1), 11 Feb 2014 (v2)

NuSTAR: Pulse of a Dead Star Powers Intense Gamma Rays

NuSTAR Discovery of a Young, Energetic Pulsar Associated with the Luminous Gamma-ray Source HESS J1640-465 - E. V. Gotthelf et al

• Astrophysical Journal 788(2) 155 (2014 Jun 20) DOI: 10.1088/0004-637X/788/2/155
  arXiv.org > astro-ph > arXiv:1405.0465 > 02 May 2014

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Author: Dr. Michael F. Corcoran

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Pulse of a Dead Star Powers Intense Gamma Rays
NASA | JPL-Caltech | NuSTAR | 2014 Sep 16

[i]The blue dot in this image marks the spot of an energetic pulsar -- the magnetic, spinning core of star that blew up in a supernova explosion.[/i] [url=http://www.nustar.caltech.edu/image/nustar140916a][b][i]Image credit: NASA/JPL-Caltech/SAO[/i][/b][/url]

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Our Milky Way galaxy is littered with the still-sizzling remains of exploded stars.

When the most massive stars explode as supernovas, they don't fade into the night, but sometimes glow ferociously with high-energy gamma rays. What powers these energetic stellar remains?

NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, is helping to untangle the mystery. The observatory's high-energy X-ray eyes were able to peer into a particular site of powerful gamma rays and confirm the source: A spinning, dead star called a pulsar. Pulsars are one of several types of stellar remnants that are left over when stars blow up in supernova explosions.

This is not the first time pulsars have been discovered to be the culprits behind intense gamma rays, but NuSTAR has helped in a case that was tougher to crack due to the distance of the object in question. NuSTAR joins NASA's Chandra X-ray Observatory and Fermi Gamma-ray Space Telescope, and the High Energy Stereoscopic System (H.E.S.S.) in Namibia, each with its own unique strengths, to better understand the evolution of these not-so-peaceful dead stars.

"The energy from this corpse of a star is enough to power the gamma-ray luminosity we are seeing," said Eric Gotthelf of Columbia University, New York. Gotthelf explained that while pulsars are often behind these gamma rays in our galaxy, other sources can be as well, including the outer shells of the supernova remnants, X-ray binary stars and star-formation regions. Gotthelf is lead author of a new paper describing the findings in the Astrophysical Journal. ...