ar X iv : a st ro - p h / 04 06 33 8 v 2 1 6 Ju n 20 04 Do We Know of any Maunder Minimum Stars ? 1

ar X iv : a st ro - p h / 04 06 33 8 v 1 1 5 Ju n 20 04 Do We Know of any Maunder Minimum Stars ? 1

Most stars previously identified as Maunder minimum stars are old stars evolved off of the main sequence. Analysis of activity measurements from the California and Carnegie Planet Search program stars and Hipparcos parallaxes implies that the canonical age-chromospheric activity relation breaks down for stars older than ∼ 6 Gyr when activity is calculated from Mount Wilson S values. Stars only ...

ar X iv : a st ro - p h / 04 06 56 7 v 1 2 4 Ju n 20 04 1

ar X iv : a st ro - p h / 98 04 15 2 v 1 1 6 A pr 1 99 8 New aspects in the theory of magnetic winds from massive hot stars

ar X iv : a st ro - p h / 04 02 54 1 v 2 1 6 Ju n 20 04 Quintessence and Thermal Matter

We investigate the effects of thermal interactions on tracking models of quintessence. We show that even Planck-suppressed interactions between matter and the quintessence field can alter its evolution qualitatively. The dark energy equation of state is in many cases strongly affected by matter couplings. We obtain a bound on the coupling between quintessence and relativistic relic particles su...

ar X iv : a st ro - p h / 04 06 65 8 v 1 2 9 Ju n 20 04 Calibration of cameras of the H . E . S . S . detector

H.E.S.S. – the High Energy Stereoscopic System– is a new system of large atmospheric Cherenkov telescopes for GeV/TeV astronomy. Each of the four telescopes of 107 m mirror area is equipped with a 960-pixel photomulitiplier-tube camera. This paper describes the methods used to convert the photomultiplier signals into the quantities needed for Cherenkov image analysis. Two independent calibratio...