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Highlights - Volume 503-3 (September I 2009)

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HIGHLIGHTS: this week in A&A

Volume 503-3 (September I 2009)

 


In section 6. Interstellar and circumstellar matter

“Radio properties of the low surface brightness SNR G65.2+5.7”, by L. Xiao, W. Reich, E. Fürst, and J.L. Han, A&A 503, p. 827

This paper describes new 6cm observations (from the Urumqi 25-metre radio telescope in China) and 11cm (Effelsberg) observations of a large, but faint SNR in the inner Galaxy, G65.2+5.7. It also brings together pieces of knowledge from the literature on this SNR and packages all the sets of data into one very well written and convincing paper that reinforces the interpretation that the SNR is an older, quite evolved remnant. 

 



In section 5. Galactic structure, stellar clusters, and populations

“Spectrum and variability of the Galactic center VHE gamma-ray source HESS J1745-290”, by F. Aharonian, A.G. Akherperjanian, G. Anton, et al, A&A 503, p. 817

For the first time, long-term (2004-2006) monitoring is reported for the TeV-bright Galactic center source HESS J1745-290. The association of this source with Sgr A East is definitively ruled out, but Sgr A* and the SNR plus pulsar wind nebula G359.95 – 0.04 remain viable candidates. The monitoring reported here shows that the spectrum and flux from the TeV source remain constant. There is no evidence of the QPOs or flaring reported from Sgr A* in other energy bands, but diffusing protons could account for the observed VHE spectrum. If the PWN is not contributing to the signal, the variations of Sgr A* must be substantially different at TeV than at lower energies, but it could contribute at least a portion of the observed flux.

 

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© Astronomy & Astrophysics 2009