منابع مشابه
Periodic orbits in warped disks
It is often assumed that a warped galaxy can be modeled by a set of rings. This paper verifies numerically the validity of this assumption by the study of periodic orbits populating a heavy self-gravitating warped disk. The phase space structure of a warped model reveals that the circular periodic orbits of a flat disk are transformed in quasi annular periodic orbits which conserve their stabil...
متن کاملBlowing up Feynman integrals
In this talk we discuss sector decomposition. This is a method to disentangle overlapping singularities through a sequence of blow-ups. We report on an open-source implementation of this algorithm to compute numerically the Laurent expansion of divergent multi-loop integrals. We also show how this method can be used to prove a theorem which relates the coefficients of the Laurent series of dime...
متن کاملSection 2.7.1 - Blowing Up
Now we come to the generalised notion of blowing up. In (I, §4) we defined the blowing up of a variety with respect to a point. Now we will define the blowing up of a noetherian scheme with respect to any closed subscheme. Since a closed subscheme corresponds to a coherent sheaf of ideals, we may as well speak of blowing up a coherent sheaf of ideals. The necessary background for this section i...
متن کاملA Physical Model of Warped Galaxy Disks
Warped H I gas layers in the outer regions of spiral galaxies usually display a noticeably twisted structure. This structure almost certainly arises primarily as a result of differential precession in the H I disk as it settles toward a preferred orientation in an underlying dark halo potential well that is not spherically symmetric. In an attempt to better understand the structure and evolutio...
متن کاملClassification of Weighted Graphs up to Blowing-up and Blowing-down
We classify weighted forests up to the blowing-up and blowing-down operations which are relevant for the study of algebraic surfaces. The word “graph” in this text means a finite undirected graph such that no edge connects a vertex to itself and at most one edge joins any given pair of vertices. A weighted graph is a graph in which each vertex is assigned an integer (called its weight). Two ope...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2003
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20030729