15028605
Topological quantum field theory and crossing number
In this paper, we construct a new topological quantum field theory of cohomological type and show that its partition function is a crossing number.
119356933
Super-Yangian Y( gl(1|1)) and its oscillator realization
On the basis of graded RTT formalism, the defining relation of the super-Yangian is derived and its oscillator realization is constructed.
123950095
Global Solutions of Einstein–Dirac Equation on the Conformal Space*
The difference between the Riemann and Lorentz spinor manifolds of four dimensions is that the Dirac operator of the former is elliptic and that of the latter is hyperbolic. Moreover the spinor group of the former is a compact group and that of the latter is a noncompact group, which is isomorphic to SL(2,C). Hence the results and their interpretation coming from the two theories would be different. In this short note we study only the Lorentz spinor manifold and, especially, the solutions of Einstein-Dirac equations on the conformal space, which is closely related to the AdS/CFT correspondence.
124820814
R-Matrices for Some Inhomogeneous Quantum Groups*
In this paper, some new generalized inhomogeneous quantum groups corresponding to the homogeneous multiparameter quantum groups are constructed, furthermore, the -matrices for these inhomogeneous quantum groups are found.
124010822
ASSOCIATIVITY OF REPRESENTATIONS AND COCYCLES OF GAUGE GROUPS
It is shown that the consistency of certain representations of group requires a mod Z-cocycle condition which leads to some topological quantization constants in corresponding anomalous algebraic relations, such as anomalous commutators and anomalous Jacobi identities. It should be pointed out that the mod Z-cocycles for gauge groups could be constructed by means of the generalized secondary characteristic classes.
123836451
ANOMALIES OF ARBITRARY GAUGE GROUP AND ITS REDUCTION GROUP, EINSTEIN AND LORENTZ ANOMALIES
Based upon the properties of the characteristic classes and their Chern-Simons secondary characteristic classes, the "Abelian" anomalies in , the Euler-Heisenberg effective actions in , as well as the non-Abelian anomalies in for arbitrary gauge group and its reduction subgroup have been investigated thoroughly and the application to the gravitational anomalies is made. It is shown that the "Abelian" anomalies of such groups are equal to each other, their Eu1er-Heisenberg actions are also closely related to each, other, and their non-Abelian anomalies are also equivalent if their common generating functional can be taken as a counter-term. For the gravitational anomalies we present the common generating functional for both non-Abelian Einstein and Lorentz anomalies in and show the relationship between them.
118439256
Photometric observations of three high mass X-ray binaries and a search for variations induced by orbital motion
We searched for long period variation in V-band, IC-band and RXTE X-ray light curves of the High Mass X-ray Binaries (HMXBs) LS 1698 / RX J1037.5-5647, HD 110432 / 1H 1249-637 and HD 161103 / RX J1744.7-2713 in an attempt to discover orbitally induced variation. Data were obtained primarily from the ASAS database and were supplemented by shorter term observations made with the 24- and 40-inch ANU telescopes and one of the robotic PROMPT telescopes. Fourier peri-odograms suggested the existence of long period variation in the V-band light curves of all three HMXBs, however folding the data at those periods did not reveal convincing periodic variation. At this point we cannot rule out the existence of long term V-band variation for these three sources and hints of longer term variation may be seen in the higher precision PROMPT data. Long term V-band observations, on the order of several years, taken at a frequency of at least once per week and with a precision of 0.01 mag, therefore still have a chance of revealing long term variation in these three HMXBs.
59125927
Cosmological Simulations using GCMHD
Radio observations of galaxy clusters show that the intra cluster medium is permeated by \mu G magnetic fields. The origin and evolution of these cosmological magnetic fields is currently not well understood and so their impact on the dynamics of structure formation is not known. Numerical simulations are required to gain a greater understanding and produce predictions for the next generation of radio telescopes. We present the galactic chemodynamics smoothed particle magnetohydrodynamic (SPMHD) code (GCMHD+), which is an MHD implementation for the cosmological smoothed particle hydrodynamic code GCD+. The results of 1, 2 and 3 dimensional tests are presented and the performance of the code is shown relative to the ATHENA grid code. GCMHD+ shows good agreement with the reference solutions produced by ATHENA. The code is then used to simulate the formation of a galaxy cluster with a simple primordial magnetic field embedded in the gas. A homogeneous seed field of 10^-11 G is amplified by a factor of 10^3 during the formation of the cluster. The results show good agreement with the profiles found in other magnetic cluster simulations of similar resolution.
118743381
General relativistic radiative transfer: formulation and emission from structured tori around black holes
Aims. We aim to construct a general relativistic radiative transfer formulation, applicable to particles with or without mass in astrophysical settings, wherein ray-tracing calculations can be performed for arbitrary geodesics for a given space-time geometry. Methods. The relativistic radiative transfer formulation is derived from first principles: conserving particle number and phase-space density. The formulation is covariant, and transfer calculations are conducted along particle geodesics connecting the emitters and the observer. The geodesics are determined through the space-time metric, which is specified beforehand. Absorption and emission in the radiative transfer calculations are treated explicitly. The particle-medium interaction is evaluated in the local inertial frame, comoving with the medium. Relativistic, geometrical and optical depth effects are treated self-consistently within an integral covariant framework. Results. We present a self-consistent general relativistic radiative transfer formulation with explicit treatment of emission and absorption. The formulation is general and is applicable to both particles with mass and without mass. The presence of particles has two major effects: firstly the particle bundle ray is no longer along the null geodesic, and secondly the intensity variation along the particle bundle ray is reduced by an aberration factor. The radiative transfer formulation can handle 3D geometrical settings and structured objects with variations and gradients in the optical depths across the objects and along the line-of-sight. Such scenarios are applicable in calculations of photon emission from complex structured accretion flows around black holes and neutrino emission from remnant neutron tori in neutron-star mergers. We apply the formulation and demonstrate radiation transfer calculations for emission from accretion tori around rotating black holes. We consider two cases: idealised optically thick tori that have a sharply defined emission boundary surface, and structured tori that allow variations in the absorption coefficient and emissivity within the tori. We show intensity images and emission spectra of the tori obtained in our calculations. Our findings in the radiative transfer calculations are summarised as follows. (i) Geometrical effects, such as lensing-induced self-occulation and multiple-image contribution are much more significant in accretion tori than geometrically thin accretion disks. (ii) Optically thin accretion tori show emission line profiles distinguishable from the profiles of lines from optically thick accretion tori and lines from optically thick geometrically thin accretion disks. (iii) The line profiles of the optically thin accretion tori have a weaker dependence on the viewing inclination angle than those of the optically thick accretion tori or accretion disks, especially at high viewing inclination angles. (iv) Limb effects are present in accretion tori with finite optical depths, due to density and temperature stratification within the tori. We note that in accretion flows onto relativistic compact objects, gravitationally induced line resonance can occur. This resonance occurs easily in 3D flows, but not in 2D flows, such as a thin accretion disk around a black hole.
14186187
Accretion Flow along a Dipolar Field: Application to Intermediate Polars
A hydrodynamic formulation for accretion flow channeled by a dipolar magnetic field is constructed using a curvi-linear coordinate system natural to the field structure. We solve the hydrodynamic equations and determine the velocity, density and temperature profiles of the post-shock accretion flow. The results are applied to accretion flows in intermediate polars. We have found that for systems with massive white dwarfs (~ 1 M ⊙ ) the temperature profiles in the flow can differ significantly to those obtained from models in which the accretion column is assumed to be cylindrical.
2064814
Ultra-Short Period Double-Degenerate Binaries
We review the current observational status of the ROSAT sources RX J1914.4+2456 and RX J0806.3+1527, and the evidence that these are ultra-short period (<10min) binary systems. We argue that an Intermediate Polar interpretation can be ruled out, that they are indeed compact binaries with a degenerate secondary, and that the period seen in the X-ray and optical is the orbital period. A white dwarf primary is preferred, but a neutron star cannot be excluded. We examine the capability of the three current double-degenerate models (Polar, Direct Accretor and Electric Star) to account for the observational characteristics of these systems. All models have difficulties with some aspects of the observations, but none can be excluded with confidence at present. The Electric Star model provides the best description, but the lifetime of this phase requires further investigation. These ultra-short period binaries will be strong gravitational wave emitters in the LISA bandpass, and because of their known source properties will be important early targets for gravitational wave studies.