83259
Measuring the Motion of the Black Hole in GRO J1655–40
We report optical spectroscopic observations of the low-mass X-ray binary GRO J1655-40 during outbursts in 1994 August-September and in 1996 June. The spectra show emission and absorption lines from the accretion disk surrounding the X-ray source, which have enabled us to measure the motion of the black hole candidate in this system. It is the first time among black hole candidates that an emission-line radial velocity curve is seen in phase with the expected motion of the primary. The projected radial velocity semiamplitude determined for the primary (KX = 76.2±7.5 km s-1), combined with estimates of the projected radial velocity semiamplitude of the companion star from previous observations (KC=228.2±3.0 km s-2), yields a 95% confidence limit, derived purely from kinematics, of MX > 5.1 M☉ for the mass of the compact object in GRO J1655-40, confirming its black hole nature.
18756154
Formation of optical lines in black-hole binaries
The HI Balmer emission lines of black-hole binaries show double-peaked profiles during the high-soft state and the quiescent state. In the high-soft state the profiles are asymmetric with a stronger red peak, but the profiles are symmetric in the quiescent state. We suggest that in the high-soft state the emission lines originate from the temperature-inversion layer caused by irradiative heating of an optically thick accretion disk. Irradiative heating also causes the formation of a disk wind, which mildly absorbs the blue peak of the lines. The double-peaked lines seen in the quiescent state arise from an optically thin disk. In the absence of a disk wind, the lines are unabsorbed and so the symmetry of the line profiles is preserved.
14786495
State transitions in LMC X-3
We carried out a multiwavelenght study of the black-hole candidate LMC X-3 with XMM-Newton. The system showed a transition to a low-hard state, in which the X-ray spectrum was well fitted by a simple power law. It then returned to a high-soft state, characterised by a strong disk-blackbody component. The line-of-sight absorption column density is <~ 4 x 10^{20} cm^{-2} consistent with the foreground Galactic absorption. This rules out wind accretion. We argue that, despite LMC X-3 being a high-mass X-ray binary, Roche-lobe overflow is the main mechanism of mass transfer. From UV/optical observations in the low-hard state, we determine that the companion is a slightly evolved B5 star with a mass M ~ 4.5 M_sun. This is indeed consistent with the secondary star being close to filling its Roche lobe.
1734663
Line emission from optically thick relativistic accretion tori
We calculate line emission from relativistic accretion tori around Kerr black holes and investigate how the line profiles depend on the viewing inclination, spin of the central black hole, parameters describing the shape of the tori, and spatial distribution of line emissivity on the torus surface. We also compare the lines with those from thin accretion disks. Our calculations show that lines from tori and lines from thin disks share several common features. In particular, at low and moderate viewing inclination angles they both have asymmetric double-peaked profiles with a tall, sharp blue peak and a shorter red peak which has an extensive red wing. At high viewing inclination angles they both have very broad, asymmetric lines which can be roughly considered as single-peaked. Torus and disk lines may show very different red and blue line wings, but the differences are due to the models for relativistic tori and disks having differing inner boundary radii. Self-eclipse and lensing play some role in shaping the torus lines, but they are effective only at high inclination angles. If inner and outer radii of an accretion torus are the same as those of an accretion disk, their line profiles show substantial differences only when inclination angles are close to 90°, and those differences manifest mostly at the central regions of the lines instead of the wings.
13854637
Ionization structure in accretion shocks with a composite cooling function
ABSTRA C T We have investigated the ionization structure of the post-shock regions of magnetic cataclysmic variables, using an analytic density and temperature structure model in which effects caused by bremsstrahlung and cyclotron cooling are considered. We find that in the majority of the shock-heated region where H- and He-like lines of the heavy elements are emitted, the collisional-ionization and corona-condition approximations are justified. We have calculated the line emissivity and ionization profiles for iron as a function of height within the post-shock flow. For low-mass white dwarfs, line emission takes place near the shock. For high-mass white dwarfs, most of the line emission takes place in regions well below the shock and hence it is less sensitive to the shock temperature. Thus, the line ratios are useful to determine the white dwarf masses for the low-mass white dwarfs, but the method is less reliable when the white dwarfs are massive. Line spectra can, however, be used to map the hydrodynamic structure of the post-shock accretion flow.
119332271
Low and High Angular Momentum Accretion Flows in BHCs: Case Study of XTE J1550-564
The 1998 outburst of XTE J1550-564 started with a hard X-ray spike, rising in less than a day and declining after 3-4 days; at the same time, the soft X-ray flux was rising with a longer timescale (~ 10 days). We suggest that the soft and the initial hard X-ray emission are produced by two different components of the accretion flow: a higher angular momentum flow, which forms the disk, and a lower angular momentum flow feeding the hot inner region. Thus, we argue that the onset of the outburst is determined by an increased mass transfer rate from the companion star, but the outburst morphology is also determined by the distribution of specific angular momentum in the accreting matter. In XTE J1550-564, we attribute the initial, impulsive low angular momentum accretion to the breaking down of magnetic confinement by the magnetically active secondary star. We show that a hard X-ray spike is seen at the onset of an outburst in other BHCs.
123862499
$SU(\nu)$ Calogero spin system and Virasoro-Witt 3-algebra
We investigate the SU(ν) Calogero spin system and scale the boost and conserved operators of this integrable many-body system by a scaling parameter. In terms of these scaled operators and appropriate scaling limit, we show that the SU(ν) Calogero spin system has an infinite-dimensional 3-algebraic symmetry, i.e., the so-called Virasoro-Witt 3-algebra. The fundamental identity (FI) condition holds for this infinite-dimensional 3-algebra.
18532275
On variations in discrete mechanics and field theory
In this paper, we propose the difference variational approach with variable step-length for discrete mechanics and field theory. Based upon the Hamilton's principle for the vertical variations and the horizontal variations, we get the equation of motion and the relevant relations between the equation of motion and conservation law of the energy/energy-momentum tensor for continuous as well as for the discrete systems, respectively. For those discrete cases, these relations determine the variable step-length of the differences. In addition, by taking the double operation of vertical exterior differential on action, we show that there should exist the Euler-Lagrange cohomology for both continuous and variable step-length difference cases in general. This indicates that the necessary and sufficient condition for symplectic/multisymplectic structure preserving properties is the relevant Euler-Lagrange one-form being closed in each case. Our approach can be applied to both the Lagrangian formalism and the Hamiltonian formalism, via discrete Legendre transformation, for the difference discrete mechanics and field theory. (C) 2003 American Institute of Physics.
16685414
Universal R-matrix Of The Super Yangian Double DY(gl(1|1))
Based on Drinfel ′ d realization of super Yangian Double DY (gl(1|1)), its pairing relations and universal R-matrix are given. By taking evaluation representation of universal R-matrix, another realization L ± (u) of DY (gl(1|1)) is obtained. These two realizations of DY (gl(1|1)) are related by the supersymmetric extension of Ding-Frenkel map. Yangian algebra was introduced by Drinfel ′ d[1, 2]. The quantum double of Yangian consists of Yangian itself and its dual with opposite comultiplication. There are three methods to define the Yangian and Yangian double: Drinfel ′ d-Jmbo [1, 3], Drinfel ′ d new realization [2] and RS approach [5] (or FRT approach [4] in the case of without center extension). The explicit isomorphism between Drinfel ′ d new realization and RS realization of Yangian double can be established through Gauss decomposition, the similar method used by Ding and Frenkel in the discussions of quantum Affine algebra. [6]. The property of Yangian double, such as quasi-triangular properties and equivalence of Drinfel ′ d and RS realization was studied well in some papers [7, 8, 9]. Although the Drinfel ′ d realization of super Yangian double [10, 11] was constructed by means of RS method and Gauss decomposition, the quasi-triangular property, such as universal R-matrix of super Yangian double has not been studied yet. In this paper, we find the Hopf pairing relations between super Yangian Y (gl(1|1)) and its dual, then construct the universal R-matrix of DY (gl(1|1)). By taking evaluation representation, we get the FRT realization of DY (gl(1|1)). Super Yangian double DY (gl(1|1)) is the Hopf algebra generated by elements
121089433
Symmetric and Asymmetric Anomalies and Effective Lagrangian
The properties of the effective Lagrangian for the low-energy Goldstone-gauge field system constructed from the Chern-Simons topological invariant are further discussed. Both the symmetric anomaly and the asymmetric anomaly are connected with this Lagrangian.
18830661
Application of Noncommutative Differential Geometry on Lattice to Anomaly Analysis in Abelian Lattice Gauge Theory
The chiral anomaly in lattice abelian gauge theory is investigated by applying noncommutative differential geometry (NCDG). A new kind of double complex and descent equation is proposed on an infinite hypercubic lattice in arbitrary even-dimensional Euclidean space in the framework of NCDG. By using the general solutions of descent equation, we derive the chiral anomaly in Abelian lattice gauge theory. The topological origin of the anomaly is nothing but the Chern classes in NCDG.