ar X iv : a st ro - p h / 98 02 16 1 v 1 1 2 Fe b 19 98 The intrinsic properties of the local interstellar medium

ar X iv : a st ro - p h / 98 02 12 1 v 2 1 1 Fe b 19 98 Distance to M 31 With the HST and Hipparcos Red Clump Stars

Following an approach by Paczy´nski & Stanek we compare red clump stars with parallaxes known to better than 10% in the Hipparcos catalog with the red clump stars observed in three fields in M31 using the HST. There are ∼ 600 and ∼ 6, 300 such stars in the two data sets, respectively. The local red clump luminosity function is well represented by a Gaussian with the peak at M I 0 ,m = −0.23, an...

ar X iv : h ep - p h / 98 02 41 9 v 1 2 5 Fe b 19 98 COURSE LARGE N QCD

ar X iv : a st ro - p h / 98 02 12 1 v 1 1 0 Fe b 19 98 Distance to M 31 With the HST and Hipparcos Red Clump Stars

Following an approach by Paczy´nski & Stanek we compare red clump stars with parallaxes known to better than 10% in the Hipparcos catalog with the red clump stars observed in three fields in M31 using the HST. There are ∼ 600 and ∼ 6, 300 such stars in the two data sets, respectively. The local red clump luminosity function is well represented by a Gaussian with the peak at M I 0 ,m = −0.23, an...

ar X iv : a st ro - p h / 98 02 06 1 v 2 2 4 Fe b 19 98 Cosmic Axion ∗

+ θ̄ 16π2 TrFμνF̃ μν (2) Since this θ̄ term violates CP invariance, the upper bound of the neutron electric dipole moment puts a strong constraint on the magnitude of θ̄, |θ̄| < 10. The smallness of θ̄ has led to the strong CP problem, “Why is θ̄ so small?” [1] We know that many small parameters in physics have led to new ideas, in most cases leading to new symmetries. For example, MW/MP ≪ 1 has led t...

ar X iv : a st ro - p h / 98 02 30 4 v 1 2 4 Fe b 19 98 1

We report the discovery with BeppoSAX-WFC of two new X-ray sources that were only seen during bursts: SAX J1753.5-2349 and SAX J1806.5-2215. For both sources, no steady emission was detected above an upper limit of 5 mCrab (2 to 8 keV) for 3 10 s around the burst events. The single burst detected from SAX J1753.52349 shows spectral softening and a black body color temperature of 2.0 keV. Follow...