A giant γ-ray flare from the magnetar SGR 1806–20

Flares back in fashion On 27 December last year, SGR1806–20, a soft γ-ray repeater in Sagittarius, released a giant flare that has been called the brightest explosion ever recorded. SGRs are X-ray stars that sporadically emit low-energy γ-ray bursts. They are thought to be magnetars: neutron stars w...

Celý popis

Uloženo v:

Podrobná bibliografie
Vydáno v:	Nature (London) Ročník 434; číslo 7037; s. 1107 - 1109
Hlavní autoři:	Palmer, D. M., Barthelmy, S., Gehrels, N., Kippen, R. M., Cayton, T., Kouveliotou, C., Eichler, D., Wijers, R. A. M. J., Woods, P. M., Granot, J., Lyubarsky, Y. E., Ramirez-Ruiz, E., Barbier, L., Chester, M., Cummings, J., Fenimore, E. E., Finger, M. H., Gaensler, B. M., Hullinger, D., Krimm, H., Markwardt, C. B., Nousek, J. A., Parsons, A., Patel, S., Sakamoto, T., Sato, G., Suzuki, M., Tueller, J.
Médium:	Journal Article
Jazyk:	angličtina
Vydáno:	London Nature Publishing Group UK 28.04.2005 Nature Publishing Nature Publishing Group
Témata:	Astronomy Earth, ocean, space Exact sciences and technology Gamma ray astronomy Gamma rays Gamma-ray sources ; gamma-ray bursts Humanities and Social Sciences letter Magnetic fields multidisciplinary Science Science (multidisciplinary) Solar flares Stellar systems. Galactic and extragalactic objects and systems. The universe Unidentified sources and radiation outside the solar system Total energy Neutron stars X ray burst Cosmic x-ray sources Cosmic gamma bursts Gamma ray burst High field Magnetic stars X ray pulsar Magnetic fields X ray emission S stars Reconfiguration
ISSN:	0028-0836, 1476-4687, 1476-4687
On-line přístup:	Získat plný text
Tagy:	Přidat tag Žádné tagy, Buďte první, kdo vytvoří štítek k tomuto záznamu!

Popis
Shrnutí:	Flares back in fashion On 27 December last year, SGR1806–20, a soft γ-ray repeater in Sagittarius, released a giant flare that has been called the brightest explosion ever recorded. SGRs are X-ray stars that sporadically emit low-energy γ-ray bursts. They are thought to be magnetars: neutron stars with observable emissions powered by magnetic dissipation. Five papers in this issue report initial and follow-up observations of this event. The data are remarkable: for instance in a fifth of a second, the flare released as much energy as the Sun radiates in a quarter of a million years. Such power can be explained by catastrophic global crust failure and magnetic reconnection on a magnetar. Releasing a hundred times the energy of the only two previous SGR giant flares, this may have been a once-in-a-lifetime event for astronomers, and for the star itself. Two classes of rotating neutron stars—soft γ-ray repeaters (SGRs) and anomalous X-ray pulsars—are magnetars 1 , whose X-ray emission is powered by a very strong magnetic field ( B ≈ 10 15 G). SGRs occasionally become ‘active’, producing many short X-ray bursts. Extremely rarely, an SGR emits a giant flare with a total energy about a thousand times higher than in a typical burst 2 , 3 , 4 . Here we report that SGR 1806–20 emitted a giant flare on 27 December 2004. The total (isotropic) flare energy is 2 × 10 46 erg, which is about a hundred times higher than the other two previously observed giant flares. The energy release probably occurred during a catastrophic reconfiguration of the neutron star's magnetic field. If the event had occurred at a larger distance, but within 40 megaparsecs, it would have resembled a short, hard γ-ray burst, suggesting that flares from extragalactic SGRs may form a subclass of such bursts.
Bibliografie:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 ObjectType-Article-2 ObjectType-Feature-1 content type line 23
ISSN:	0028-0836 1476-4687 1476-4687
DOI:	10.1038/nature03525