ar X iv : a st ro - p h / 98 02 02 8 v 1 3 F eb 1 99 8 Phase Transitions in Neutron Stars

ar X iv : a st ro - p h / 98 02 08 2 v 1 6 F eb 1 99 8 What is the True Covering Factor of Absorbing Matter in BALQSO ’ s ?

ar X iv : a st ro - p h / 98 02 02 7 v 1 3 F eb 1 99 8 Recalibration of Luminosity –

A recalibration of the luminosity–linewidth technique is discussed which introduces (i) new cluster calibration data, (ii) new corrections for reddening as a function of inclination, and (iii) a new zero-point calibration using 13 galaxies with distances determined via the cepheid period– luminosity method. It is found that H 0 = 82 ± 16 km s −1 Mpc −1 (95% confidence).

ar X iv : a st ro - p h / 98 02 06 3 v 1 5 F eb 1 99 8 The Redshift Distribution of Distant Sources from Gravitational Depletion in Clusters

Gravitational lensing can be used to analyze the redshift distribution of faint galaxies. In particular the magnification bias modifies locally the galaxy number density of lensed sources observed in lensing clusters. This depletion area probes the redshift distribution of galaxies beyond B = 25. In this proceedings I present this new tool to infer the redhsift distribution of faint galaxies.

ar X iv : a st ro - p h / 99 02 06 2 v 1 4 F eb 1 99 9 SOURCES OF RELATIVISTIC JETS IN THE GALAXY

ar X iv : a st ro - p h / 98 02 08 8 v 1 7 F eb 1 99 8 to appear in the AJ The Distance to the M 31 Globular Cluster System

The distance to the centroid of the M31 globular cluster system is determined by fitting theoretical isochrones to the observed red-giant branches of fourteen globular clusters in M31. The mean true distance modulus of the M31 globular clusters is found to be µ 0 = 24.47 ± 0.07 mag. This is consistent with distance moduli for M31 that have been obtained using other distance indicators.