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|Title:||Simultaneous HESS and Chandra observations of Sagitarius A(star) during an X-ray flare|
Barres de Almaida, U.
|Citation:||Astronomy and Astrophysics, 2008; 492(1):L25-L28|
|F. Aharonian, A. G. Akhperjanian, U. Barres de Almeida, A. R. Bazer-Bachi, Y. Becherini ... Gavin P. Rowell ... et al.|
|Abstract:||The rapidly varying (∼10 min timescale) non-thermal X-ray emission observed from Sgr A implies that particle acceleration is occuring close to the event horizon of the supermassive black hole. The TeV γ-ray source HESS J1745−290 is coincident with Sgr A and may be closely related to its X-ray emission. Simultaneous X-ray and TeV observations are required to elucidate the relationship between these objects. We report on joint HESS/Chandra observations performed in July 2005, during which an X-ray flare was detected. Despite a factor of ≈9 increase in the X-ray flux of Sgr A , no evidence is found for an increase in the TeV γ-ray flux from this region. We find that an increase in the γ-ray flux of a factor of 2 or greater can be excluded at a confidence level of 99%. This finding disfavours scenarios in which the keV and TeV emission are associated with the same population of accelerated particles and in which the bulk of the γ-ray emission is produced within ∼1014 cm (∼100 RS) of the supermassive black hole.|
|Keywords:||gamma rays: observations; X-rays: individuals: Sgr A*|
|Description:||Copyright © ESO 2008|
|Rights:||Copyright © ESO 2008|
|Appears in Collections:||Chemistry and Physics publications|
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