X iv : a st ro - p h / 97 12 07 5 v 1 4 D ec 1 99 7 Constraining the Power Spectrum Using the Column Density Distribution : a Status Report

ar X iv : a st ro - p h / 97 12 22 1 v 1 1 7 D ec 1 99 7 1 The X – ray spectrum of the polar BY Cam

ASCA and GINGA X-ray data from the magnetic Cataclysmic Variable BY Cam show that the spectrum is strongly affected by complex absorption, probably from the pre-shock accretion column. The intrinsic emission from the shock is significantly better described by the theoretically expected multi-temperature structure rather than a single temperature plasma, but with cyclotron cooling probably suppr...

ar X iv : a st ro - p h / 97 12 26 7 v 1 1 8 D ec 1 99 7 X - Ray Emission from the Radio Pulsar PSR J 1105 − 6107

We have detected significant X-ray emission from the direction of the young radio pulsar PSR J1105−6107 using the ASCA Observatory. The 11σ detection includes 460 background-subtracted source counts derived using data from all four ASCA detectors. The emission shows no evidence of pulsations; the pulsed fraction is less than 31%, at the 90% confidence level. The X-ray emission can be characteri...

ar X iv : a st ro - p h / 98 12 16 7 v 1 9 D ec 1 99 8 LYMAN BREAK GALAXIES AT z ∼ 3 AND BEYOND

We report on the status of large surveys of photometrically selected star forming galaxies at z ∼ 3 and z ∼ 4, with particular emphasis on both the advantages and the limitations of selecting objects using the “Lyman break” technique. Current results on the luminosity functions, luminosity densities, color distribution, star formation rates, clustering properties, and the differential evolution...

X iv : a st ro - p h / 96 12 22 7 v 1 2 3 D ec 1 99 6 Conditional calculus on fractal structures and its application to galaxy distribution

ar X iv : a st ro - p h / 97 12 23 9 v 1 1 7 D ec 1 99 7 Frequency Dependent Lags - A Common Phenomenon of Accreting Sources

The Fourier frequency dependent hard X-ray lag, first discovered from the analysis of aperiodic variability of the light curves of the black hole candidate Cygnus X-1, turns out to be a property shared by several other accreting compact sources. We show that the lag can be explained in terms of Comptonization process in coronae of hot electrons with inhomogeneous density distributions. The dens...