A Fourier-Based Algorithm for Modelling Aberrations in HETE-2's Imaging System

The High-Energy Transient Explorer (HETE-2), launched in October 2000, is a satellite experiment dedicated to the study of gamma-ray bursts in a very wide energy range from soft X-ray to gamma-ray wavelengths. The intermediate X-ray range (2-30keV) is covered by the Wide-field X-ray Monitor WXM, a coded aperture imager. In this article, an algorithm for reconstructing the positions of gamma-ray bursts is described, which is capable of correcting systematic aberrations to approximately 1 arcmin throughout the field of view. Functionality and performance of this algorithm have been validated using data from Monte Carlo simulations as well as from astrometric observations of the X-ray source Scorpius X-1.Comment: 14 pages, 9 figures, 2 tables; Nucl.Instr.Meth., in pres

Twisted Elliptic Genera of N=2 SCFTs in Two Dimensions

The elliptic genera of two-dimensional N=2 superconformal field theories can be twisted by the action of the integral Heisenberg group if their U(1) charges are fractional. The basic properties of the resulting twisted elliptic genera and the associated twisted Witten indices are investigated with due attention to their behaviors in orbifoldization. Our findings are illustrated by and applied to several concrete examples. We give a better understanding of the duality phenomenon observed long before for certain Landau-Ginzburg models. We revisit and prove an old conjecture of Witten which states that every ADE Landau-Ginzburg model and the corresponding minimal model share the same elliptic genus. Mathematically, we establish ADE generalizations of the quintuple product identity.Comment: 28 pages; v2 refs adde

String Field Theory from IIB Matrix Model

We derive Schwinger-Dyson equations for the Wilson loops of a type IIB matrix model. Superstring coordinates are introduced through the construction of the loop space. We show that the continuum limit of the loop equation reproduces the light-cone superstring field theory of type IIB superstring in the large-N limit. We find that the interacting string theory can be obtained in the double scaling limit as it is expected.Comment: 21 pages, Latex, 1 figur