36,928 research outputs found
Irregularity in gamma ray source spectra as a signature of axionlike particles
Oscillations from high energy photons into light pseudoscalar particles in an
external magnetic field are expected to occur in some extensions of the
standard model. It is usually assumed that those axionlike particles (ALPs)
could produce a drop in the energy spectra of gamma ray sources and possibly
decrease the opacity of the Universe for TeV gamma rays. We show here that
these assumptions are in fact based on an average behavior that cannot happen
in real observations of single sources. We propose a new method to search for
photon-ALP oscillations, taking advantage of the fact that a single observation
would deviate from the average expectation. Our method is based on the search
for irregularities in the energy spectra of gamma ray sources. We predict
features that are unlikely to be produced by known astrophysical processes and
a new signature of ALPs that is easily falsifiable.Comment: 6 pages, 3 figures, matches accepted version, improved discussion on
magnetic field models in v
Real Time in a Real Operating System
this paper, be stamped with ecclesiastical authorit
The communication processor of TUMULT-64
Tumult (Twente University MULTi-processor system) is a modular extendible multi-processor system designed and implemented at the Twente University of Technology in co-operation with Oce Nederland B.V. and the Dr. Neher Laboratories (Dutch PTT). Characteristics of the hardware are: MIMD type, distributed memory, message passing, high performance, real-time and fault tolerant. A distributed real-time operating system has been realized, consisting of a multi-tasking kernel per node, inter process communication via typed messages and a distributed file system. In this paper first a brief description of the system is given, after that the architecture of the communication processor will be discussed. Reduction of the communication overhead due to message passing will be emphasized.\ud
\u
Fisher's equation and the inflation risk premium in a simple endowment economy
Inflation (Finance) ; Bonds ; Econometric models
On the identification of structural vector autoregressions
Vector autoregression
- …