Title of article :
The present-day chemical composition of the SMC from UVES spectra of the sharp-lined, B-type dwarf AV 304
Author/Authors :
Dufton، P. L. نويسنده , , Rolleston، W. R. J. نويسنده , , Venn، K. نويسنده , , Tolstoy، E. نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2003
Abstract :
Using the HEGRA system of imaging atmospheric Cherenkov telescopes, the Andromeda galaxy (M 31) was surveyed for TeV gamma ray emission. Given the large field of view of the HEGRA telescopes, three pointings were sufficient to cover all of M 31, including also M 32 and NGC 205. No indications for point sources of TeV gamma rays were found. Upper limits are given at a level of a few percent of the Crab flux. A specific search for monoenergetic gamma-ray lines from annihilation of supersymmetric dark matter particles accumulating near the center of M 31 resulted in flux limits in the 10-13 cm -2 s -1 range, well above the predicted MSSM flux levels except for models with pronounced dark-matter spikes or strongly enhanced annihilation rates.
Keywords :
Abundances , atmospheres , early-type , Individual , Small Magellanic Cloud , galaxies , stars
Journal title :
Astronomy and Astrophysics
Journal title :
Astronomy and Astrophysics