ar X iv : 0 90 1 . 43 63 v 1 [ as tr o - ph . S R ] 2 7 Ja n 20 09 The supernova rate : a critical ingredient and an important tool

ar X iv : 0 90 1 . 39 43 v 1 [ as tr o - ph . S R ] 2 6 Ja n 20 09 Solar analogues in open clusters : The case of M 67

Solar analogues are fundamental targets for a better understanding of our Sun and our Solar System. Usually, this research is limited to field stars, which offer several advantages and limitations. In this work, we present the results of a research of solar twins performed for the first time in a open cluster, namely M67. Our analysis allowed us to find five solar twins and also to derive a sol...

ar X iv : 0 80 1 . 35 64 v 1 [ as tr o - ph ] 2 3 Ja n 20 08 Local Phase Space - Shaped by Chaos ?

ar X iv : 0 90 1 . 42 60 v 1 [ as tr o - ph . H E ] 2 7 Ja n 20 09 The Cannonball Model Of Long GRBs - Overview

During the past ten years, the predictions of the cannonball (CB) model of gamma ray bursts (GRBs) were repeatedly confronted with the mounting data from spaceand ground-based observations of GRBs and their afterglows (AGs). The two underlying radiation mechanisms of the model, inverse Compton scattering (ICS) and synchrotron radiation (SR), provided an accurate description of the prompt and af...

ar X iv : 0 90 1 . 27 24 v 1 [ as tr o - ph . C O ] 1 8 Ja n 20 09 A Decade of Dark Energy : 1998 - 2008

The years 1998 to 2008 were very exciting years for cosmology. It was a pleasure to accept this invitation to describe my contributions to the development of our knowledge and understanding of the universe over the course of the past decade. Here, I begin by describing some of my work on radio galaxies as a modified standard yardstick and go on to describe modelindependent studies of the accele...

ar X iv : 0 90 1 . 46 64 v 1 [ cs . L O ] 2 9 Ja n 20 09 Square root meadows ∗

Let Q0 denote the rational numbers expanded to a meadow by totalizing inversion such that 0 = 0. Q0 can be expanded by a total sign function s that extracts the sign of a rational number. In this paper we discuss an extension Q0(s, √ ) of the signed rationals in which every number has a unique square root.