Browsing Astronomy and Astrophysics by Title
Now showing items 98117 of 160

Observational Constraints on the Completeness of Space near Astrophysical Objects
We consider the observational effects of a deficit angle, w, in the topology of the solar system and in the 'double pulsar' system PSR J07373039A/B. Using observations of the perihelion precession of Mercury, and the ... 
Observational Cosmology in Macroscopic Gravity
We discuss the construction of cosmological models within the framework of Macroscopic Gravity (MG), which is a theory that models the effects of averaging the geometry of spacetime on large scales. We find new exact ... 
On symmetric Fixed Points and Superconformality
(201105) 
On Regular Hypergraphs of High Girth
(20140310)We give lower bounds on the maximum possible girth of an runiform, dregular hypergraph with at most n vertices, using the definition of a hypergraph cycle due to Berge. These differ from the trivial upper bound by an ... 
On the absence of the usual weakfield limit, and the impossibility of embedding some known solutions for isolated masses in cosmologies with f(R) dark energy
(20121002)The problem of matching different regions of spacetime in order to construct inhomogeneous cosmological models is investigated in the context of Lagrangian theories of gravity constructed from general analytic functions ... 
On the Emergence of Accelerating Cosmic Expansion in f(R) Theories of Gravity
We consider cosmological modelling in $f(R)$ theories of gravity, using both topdown and bottomup constructions. The topdown models are based on RobertsonWalker geometries, and the bottomup constructions are built by ... 
On the superconformal index of Argyres–Douglas theories
(20160108) 
Optomechanical design of a new cross dispersion unit for the CRIRES+ high resolution spectrograph for the VLT
(20140101)© 2014 SPIE. CRIRES is one of the few IR (0.925.2 μm) highresolution spectrographs in operation at the VLT since 2006. Despite good performance it suffers a limitation that significantly hampers its ability: a small ... 
The Parameterised PostNewtonian Limit of Bimetric Theories of Gravity
We consider the postNewtonian limit of a general class of bimetric theories of gravity, in which both metrics are dynamical. The established parameterised postNewtonian approach is followed as closely as possible, although ... 
The Parameterised PostNewtonian Limit of FourthOrder Theories of Gravity
We determine the full postNewtonian limit of theories of gravity that extend general relativity by replacing the Ricci scalar, R, in the generating Lagrangian by some analytic function, f(R). We restrict ourselves to ... 
The partition function of ABJ theory
(201305) 
Perturbation Theory in LemaitreTolmanBondi Cosmology
The LemaitreTolmanBondi solution has received much attention as a possible alternative to Dark Energy, as it is able to account for the apparent acceleration of the Universe without any exotic matter content. However, ... 
Phosphorusbearing molecules in solartype star forming regions: First PO detection
(Blackwell Publishing Inc., 20161111) 
Piecewise Silence in Discrete Cosmological Models
We consider a family of cosmological models in which all mass is confined to a regular lattice of identical black holes. By exploiting the reflection symmetry about planes that bisect these lattices into identical halves, ... 
PostNewtonian cosmological modelling
(20150526) 
The Power of General Relativity
We study the cosmological and weakfield properties of theories of gravity derived by extending general relativity by means of a Lagrangian proportional to $R^{1+\delta}$. This scalefree extension reduces to general ... 
Properties of Black Hole Radiation From Tunnelling
We consider the spacetime associated with the evaporation of a black hole by quantum mechanical tunnelling events. It is shown that the surface through which tunnelling occurs is distinct from the global event horizon, ...