Astronomy Astrophysics manuscript no.

Astronomy Astrophysics manuscript no. March 7, 2002

Astronomy Astrophysics manuscript no. H4001 February 17, 2003

Astronomy and Astrophysics

We present a short re–evaluation of a recently published time delay estimate for the gravitational lens system HE 1104–1805 with emphasis on important methodological aspects: bias of the statistics, inconsistency of the methods and use of the purposeful selection of data points (or so–called " cleaning ") at the preprocessing stage. We show how the inadequate use of simple analysis methods can ...

Astronomy and Astrophysics

We report on low-resolution spectroscopy of GX339–4 during its current, extended X-ray 'off' state in May 2000 (r=20.1) obtained with the VLT Focal Re-ducer/low dispersion Spectrograph (FORS1). Although we do not positively detect the secondary star in GX339–4 we place an upper limit of 30 percent on the contribution of a " normal " K-type secondary star spectrum to the observed flux. Using thi...

The Crisis Confronting Standard Big Bang Nucleosynthesis

This manuscript is the written version of the material I attempted to cover at “Critical Dialogues in Cosmology”. My position is that although BBN is inevitable in an expanding universe filled with radiation and baryons, at present there is a conflict between the abundances of the light nuclides predicted by standard, big bang nucleosynthesis (SBBN) and those inferred from current observational...