ar X iv : a st ro - p h / 93 05 00 2 v 1 6 M ay 1 99 3 Visibility of Gravitational Lenses and the Cosmological Constant Problem

ar X iv : a st ro - p h / 00 05 59 4 v 1 3 1 M ay 2 00 0 SUPERNOVAE DATA : COSMOLOGICAL CONSTANT OR RULING OUT THE COSMOLOGICAL PRINCIPLE ?

Analysed in the framework of homogeneous FLRW models, the magnitude-redshift data from high redshift supernovae yield, as a primary result, a strictly positive cosmological constant. Another reading of the currently published measurements does not exclude a possible ruling out of the Cosmological Principle and, thus, also, of the cosmological constant hypothesis. It is shown how shortly coming ...

ar X iv : a st ro - p h / 06 05 06 7 v 1 2 M ay 2 00 6 Sensitivity and pointing accuracy of the NEMO km 3 telescope

ar X iv : a st ro - p h / 96 05 17 6 v 1 2 9 M ay 1 99 6 A time – dependent “ Cosmological Constant ”

We construct a cosmological toy model in which a step-function “cosmological constant” is taken into consideration beside ordinary matter. We assume that Λ takes two values depending on the epoch, and matter goes from a radiation dominated era to a dust dominated era. The model is exactly solvable and it can be compared with recent observations. PACS: 98.80. Cq, 98.70. Vc e-mail address: capozz...

ar X iv : a st ro - p h / 92 05 00 5 v 1 9 M ay 1 99 2 UCSBTH – 92 – 05 April 1992 CHAOTIC DARK MATTER

A very weakly coupled scalar field with mass m and initial vacuum expectation value V will provide enough mass to close the universe provided V ≃ (3 × 10 8 GeV)(100 GeV/m) 1/4. We discuss possible models in which such a field could arise. (a) Electronic address (internet): [email protected].

ar X iv : a st ro - p h / 99 05 37 6 v 1 2 8 M ay 1 99 9 A 6 . 4 - hr positive superhump period in TV