June 2000 arXiv papers — page 24

N. S. Ananikian, R. G. Ghulghazaryan

A general analytical formula for recurrence relations of multisite interaction Ising models in an external magnetic field on the Cayley-type lattices is derived. Using the theory of complex analytical dynamics on the Riemann sphere, a numerical algorithm to obtain Yang-Lee and Fisher zeros of the models is developed. It is shown that the sets of Yang-Lee and

S. A. Artamonov, V. R. Shaginyan

A model of a strongly correlated electron liquid based on the fermion condensation (FC) is extended to high-temperature superconductors. Within our model, the appearance of FC presents a boundary separating the region of a strongly interacting electron liquid from the region of a strongly correlated electron liquid. We study the superconductivity of a strong

Shi-Jie Yang, Yue Yu, Zhao-Bin Su

The ground state cohesive energies per electron of the composite fermion (CF) Fermi sea, the Laughlin state and the charge density wave (CDW) at higher Landau levels (LLs) are computed. It is shown that whereas for $n\geq 2$ LL, the CDW state is generally more energetically preferable than those of the CF liquid and the Laughlin liquid, the $ν=4+1/6$ CF liqu

H. -J. Lee, D. -P. Min, B. -Y. Park, M. Rho

We study the gluon polarization contribution at the quark model renormalization scale to the proton spin, $Γ$, in the chiral bag model. It is evaluated by taking the expectation value of the forward matrix element of a local gluon operator in the axial gauge $A^+=0$. It is shown that the confining boundary condition for the color electric field plays an impo

H. W. Diehl, M. Shpot

The critical behavior of d-dimensional systems with an n-component order parameter is reconsidered at (m,d,n)-Lifshitz points, where a wave-vector instability occurs in an m-dimensional subspace of ${\mathbb R}^d$. Our aim is to sort out which ones of the previously published partly contradictory $ε$-expansion results to second order in $ε=4+\frac{m}{2}-d$ a

Pi-Gang Luan, Zhen Ye

We study acoustic propagation in one dimensional water ducts containing many air-filled blocks. The acoustic band structures for the periodic arrangements of the blocks is calculated, whereas the transmission for various random configurations of the blocks is computed by the transfer matrix method. It is shown that waves at all frequencies become localized e

Yoon-Ho Kim, Sergei P. Kulik, Morton H. Rubin, Yanhua Shih

We show in this Comment that the interpretation of experimental data as well as the theory presented in Atatüre et al. [Phys. Rev. Lett. 84, 618 (2000)] are incorrect and discuss why such a scheme cannot be used to "recover" high-visibility quantum interference.

T. Okazaki, Y. Taniguchi

Growing evidence has been accumulated for that some gas-rich dwarf galaxies are formed from material liberated by galaxy collisions and/or mergers. Also, gas-poor dwarf elliptical galaxies are often found in the central regions of clusters of galaxies. These observations suggest strongly that the formation of most dwarf galaxies is linked to galaxy interacti

M. B. Ruskai

In many physically realistic models of quantum computation, Pauli exchange interactions cause a special type of two-qubit errors, called exchange errors, to occur as a first order effect of couplings within the computer. We discuss the physical mechanisms behind exchange errors and codes designed to explicitly deal with them.

V. M. Entin, I. I. Ryabtsev, A. E. BoguslavskiI, I. M. Beterov

A nondegenerate four-level N-type scheme was experimentally implemented to observe electromagnetically induced transparency (EIT) at the $^{87}$Rb D$_{2}$ line. Radiations of two independent external-cavity semiconductor lasers were used in the experiment, the current of one of them being modulated at a frequency equal to the hyperfine-splitting frequency of

G. Mauro D'Ariano, Lorenzo Maccone, Matteo G. A. Paris

Any method for estimating the ensemble average of arbitrary operator (observables or not, including the density matrix) relates the quantity of interest to a complete set of observables, i.e. a quorum}. This corresponds to an expansion on an irreducible set of operators in the Liouville space. We give two general characterizations of these sets. All the know

Richard Cleve, John Watrous

We give new bounds on the circuit complexity of the quantum Fourier transform (QFT). We give an upper bound of O(log n + log log (1/epsilon)) on the circuit depth for computing an approximation of the QFT with respect to the modulus 2^n with error bounded by epsilon. Thus, even for exponentially small error, our circuits have depth O(log n). The best previou

S. J. van Enk, H. J. Kimble

We construct 3-D solutions of Maxwell's equations that describe Gaussian light beams focused by a strong lens. We investigate the interaction of such beams with single atoms in free space and the interplay between angular and quantum properties of the scattered radiation. We compare the exact results with those obtained with paraxial light beams and from

Bao-Sen Shi, Yun-Kun Jiang, Guang-Can Guo

In this letter, two different probabilistic teleportations of a two-particle entangled state by pure entangled three-particle state are shown. Their successful probabilities are different.

Stuart Henderson, David Cinabro

The CESR/CLEO Phase II interaction region is described. The operational experience with beam-generated detector backgrounds is reviewed. The status of our understanding of beam-generated detector backgrounds at CESR is described and comparisons of background measurements with simulation predictions are presented.

E. Oset, S. Hirenzaki, Y. Okumura, A. Ramos

We review recent work on various topics related to the modification of kaon properties in nuclei. After a brief exposition of the kaon-nucleon and kaon-nucleus interaction, results from the application to kaonic atoms, renormalization of the f0 and a0 scalar resonances in nuclei and phi decay in the nucleus are shown.

A. V. Nesterov, V. S. Vasilevsky, O. F. Chernov

The structure of $^8$He is investigated within a three-cluster microscopic model. The three-cluster configuration $α+^2n+^2n$ was used to describe the properties of the ground state of the nucleus. The obtained results evidently indicate the existence of a neutron halo in $^8$He.

P. C. Matthews, S. M. Cox

Pattern formation in systems with a conserved quantity is considered by studying the appropriate amplitude equations. The conservation law leads to a large-scale neutral mode that must be included in the asymptotic analysis for pattern formation near onset. Near a stationary bifurcation, the usual Ginzburg--Landau equation for the amplitude of the pattern is

C. Dong, G. Mason

The radical of a vertex operator algebra associated to a module is defined and computed.

P. J. Forrester, D. S. McAnally

In the theory of symmetric Jack polynomials the coefficients in the expansion of the $p$th elementary symmetric function $e_p(z)$ times a Jack polynomial expressed as a series in Jack polynomials are known explicitly. Here analogues of this result for the non-symmetric Jack polynomials $E_η(z)$ are explored. Necessary conditions for non-zero coefficients in

C. Dong, G. Yamskulna

Let V be a simple vertex operator algebra and G a finite automorphism group. Then there is a natural right G-action on the set of all inequivalent irreducible V-modules. Let S be a finite set of inequivalent irreducible V-modules which is closed under the action of G. There is a finite dimensional semisimple associative algebra A_α(G,S) for a suitable 2-cocy

Yair N. Minsky

This expository article discusses some connections between the geometry of a hyperbolic 3-manifold homotopy-equivalent to a surface, and the combinatorial properties of its end invariants. In particular a necessary and sufficient condition is stated for the manifold to have arbitrarily short geodesics, in terms of a sequence of coefficients called subsurface

Steven Duplij

One-parameter semigroups of antitriangle idempotent supermatrices and corresponding superoperator semigroups are introduced and investigated. It is shown that $t$-linear idempotent superoperators and exponential superoperators are mutually dual in some sense, and the first gives additional to exponential solution to the initial Cauchy problem. The correspond

Daniela Bigatti

The present review aims both to offer some motivations and mathematical prerequisites for a study of NCG from the viewpoint of a theoretical physicist and to show a few applications to matrix theory and results obtained. Lectures given by the author at the TMR School on contemporary string theory and brane physics, 26 Jan--2 Feb 2000, Torino.

Edward Witten

This paper is devoted to a systematic discussion of the supersymmetric index Tr (-1)^F for the minimal supersymmetric Yang-Mills theory -- with any simple gauge group G -- primarily in four spacetime dimensions. The index has refinements that probe confinement and oblique confinement and the possible spontaneous breaking of chiral symmetry and of global symm

Ofer Aharony, Nick Dorey, S. Prem Kumar

We discuss the mass-deformed N=4 SU(N) supersymmetric Yang-Mills theory (also known as the N=1* theory). We analyze how the correlation functions of this theory transform under S-duality, and which correlation functions depend holomorphically on the complexified gauge coupling τ. We provide exact modular-covariant expressions for the vacuum expectation value

E. G. Floratos, S. Nicolis

We construct quantum evolution operators on the space of states, that is represented by the vertices of the n-dimensional unit hypercube. They realize the metaplectic representation of the modular group SL(2,Z(2^n)). By construction this representation acts in a natural way on the coordinates of the non-commutative 2-torus,T^2, and thus is relevant for nonco

Aristophanes Dimakis, Folkert Muller-Hoissen

We discuss a relation between bicomplexes and integrable models, and consider corresponding noncommutative (Moyal) deformations. As an example, a noncommutative version of a Toda field theory is presented.

Kai Chen, Bo-yu Hou, Wen-Li Yang

We study the $C_{n}$ and $BC_{n}$ Ruijsenaars-Schneider(RS) models with interaction potential of trigonometric and rational types. The Lax pairs for these models are constructed and the involutive Hamiltonians are also given. Taking nonrelativistic limit, we also obtain the Lax pairs for the corresponding Calogero-Moser systems.

Tibor Torma

We find all possible static embeddings of a 4-brane in any dimension-6 spacetime with 4-dimensional Poincare symmetry and a negative cosmological constant, subject to orbifolding across the brane. Our new solutions allow intersecting branes at an angle determined by a new dynamical parameter. A collection of branes intersecting in one 3-brane allows an arbit

G. Lopez Castro, J. Pestieau, C. Smith, S. Trine

Positronium annihilation amplitudes that are computed by assuming a factorization approximation with on-shell intermediate leptons do not exhibit good analytical behaviour. Using dispersion techniques, we find new contributions that interfere with the known results to restore analytical properties. Those new amplitudes which cannot be obtained using standard

Gregory W. Anderson, Tomas Blazek

We have computed the Clebsch-Gordan coefficients for the product (000001) $\otimes$ (000001), where (000001) is the adjoint 78-dimensional representation of $E_6$. The results are presented for the dominant weights of the irreducible representations in this product. As a simple application we express the singlet operator in $ 27 \otimes 78 \otimes \bar{27}$

G. Lopez Castro, J. Pestieau, C. Smith, S. Trine

Positronium decay rates are computed at the one-loop level, using convolution-type factorized amplitudes. The dynamics of this factorization is probed with dispersion relations, showing that unallowed approximations are usually made, and some ordre alpha^2 corrections missed. Further, we discuss the relevance of the Schrodinger wavefunction as the basis for

J. F. Beacom, R. N. Boyd, A. Mezzacappa

Early black hole formation in a core-collapse supernova will abruptly truncate the neutrino fluxes. The sharp cutoff can be used to make model-independent time-of-flight neutrino mass tests. Assuming a neutrino luminosity of $10^{52}$ erg/s per flavor at cutoff and a distance of 10 kpc, SuperKamiokande can detect an electron neutrino mass as small as 1.8 eV,

G. A. Kozlov, M. Baldicchi

We reformulate the dual gauge model of the long-distance Yang-Mills theory in terms of the two-point Wightman functions formalism. In the flux-tube scheme of Abelian dominance and monopole condensation, the analytic expressions of both monopole- and dual gauge boson-fields propagators are obtained. Formally, new features of higher order quadratic equations f

L. D. Soloviev

It is shown that the eigenstates of the quantized simplest closed (elliptic) Nambu -- Goto string, called glueballs, have quantum numbers I^Gj^{PC}=0^+j^{++}. Lightest glueballs have spins j=0,1 and 2 and the same mass 1500 +/- 20 MeV. They correspond to f_0(1500), f_1(1510) and f_2(1565)- mesons. Next glueballs have j=0,1,2,3,4 and the same mass 2610 +/- 20

W. Beenakker, A. Werthenbach

We describe a formalism for calculating electroweak Sudakov logarithms in the Coulomb gauge. This formalism is applicable to arbitrary electroweak processes. For illustration we focus on the specific reactions e^+e^- -> f \bar{f} and e^+e^- -> W_T^+W_T^-, W_L^+W_L^-, which contain all the salient details of dealing with the various types of particles. We dis

V. A. Khoze, A. D. Martin, M. G. Ryskin

We quantify the rate of double diffractive Higgs/dijet production at $pp$ (or $p\bar{p}$) colliders. The suppression due to QCD bremsstrahlung is calculated perturbatively up to single $\log$ accuracy. The survival probability of the rapidity gaps is discussed. A first comparison with experiment is made.

Chao-Shang Huang, Chun Liu, Chi-Tau Yan

Within the HQET, the heavy to light vector meson transitions are systematically analyzed to the order of 1/m_Q. Besides the four universal functions at the leading order, there are twenty-two independent universal form factors at the order of 1/m_Q. Both the semileptonic decay B->ρwhich is relevant to the |V_{ub}| extraction, and the penguin induced decay B

Shou Hua Zhu

In this report, instead to give comprehensive review on two important research fields during my first term postdoctoral working period: Higgs and FCNC physics, I will collect part of my recently works on it. Charged Higgs is the distinguished signature of new physics, in this report, I review my two works on charged Higgs associated production with top quark

Yong-Yeon Keum, Hsiang-nan Li

We compare the factorization approach, the perturbative QCD approach and the Beneke-Buchalla-Neubert-Sachrajda approach to nonleptonic charmless $B$ meson decays. We discuss their treatments of factorizable, nonfactorizable, and annihilation contributions, infrared-cutoff and scale dependences, and strong phases. It is proposed that measurement of CP asymmet

Xiao-Gang He

Due a mistake in identifying the operators $O_9$ and $O_{10}$ which leads to errorous expressions in eq. 9. With the correct expressions (exchange c_9 and c_{10} in eq. 9), the analysis followed are invalide.

Sadataka Furui, Bilal Masud

In the analysis of the energy of the four-quark system obtained in the SU(2) lattice Monte Carlo, the f-model in which the transition potential is expressed in the form $f=f_c exp(-k_A b_s A-k_P\sqrt{b_s}P)$, where A is the area and P is the perimeter of the Wilson loop, was successful in the simple configurations of the four quarks. In the case of tetrahedr

Hideo Nakajima, Sadataka Furui

The Kugo-Ojima color confinement criterion, which is based on the BRST symmetry of QCD is numerically tested by the lattice Landau gauge simulation. We first discuss the BRST symmetry on the lattice and the Gribov copy problem. The horizon function defined by Zwanziger based on the U-linear definition of the gauge field and that based on log U are compared.

E. Follana, H. Panagopoulos

We calculate the critical value of the hopping parameter, $κ_c$, in Lattice QCD with Wilson fermions, to two loops in perturbation theory. This quantity is an additive renormalization; as such, it is characterized not only by the standard caveats regarding the asymptotic nature of perturbative results, but also by a linear divergence in the lattice spacing.

S. I. Manayenkov

Precise formulas are derived for the expected values $<ξ>$, $<η>$ and variances $δξ^2$, $δη^2$ of random variables $ξ$, $η$ describing the spin asymmetry of some reaction when a background process contribution is negligible and appreciable, respectively. The variances of $ξ$ and $η$ are proved to be finite. This property differs from that of the Caushy distr

Guillermo A. González, Patricio S. Letelier

Two families of models of rotating relativistic disks based on Taub-NUT and Kerr metrics are constructed using the well-known &#34;displace, cut and reflect&#34; method. We find that for disks built from a generic stationary axially symmetric metric the &#34;sound velocity&#34;, $(pressure/density)^{1/2}$, is equal to the geometric mean of the prograde and r

John C. Henderson, Eric Brill

Three state-of-the-art statistical parsers are combined to produce more accurate parses, as well as new bounds on achievable Treebank parsing accuracy. Two general approaches are presented and two combination techniques are described for each approach. Both parametric and non-parametric models are explored. The resulting parsers surpass the best previously p

V. M. Kendon, M. E. Cates, J-C. Desplat, I. Pagonabarraga

The late-stage demixing following spinodal decomposition of a three-dimensional symmetric binary fluid mixture is studied numerically, using a thermodynamicaly consistent lattice Boltzmann method. We combine results from simulations with different numerical parameters to obtain an unprecendented range of length and time scales when expressed in reduced physi

V. Yu. Butko, J. F. DiTusa, P. W. Adams

Electron tunneling measurements of the density of states (DOS) in ultra-thin Be films reveal that a correlation gap mediates their insulating behavior. In films with sheet resistance $R<5000Ω$ the correlation singularity appears as the usual perturbative $ln(V)$ zero bias anomaly (ZBA) in the DOS. As R is increased further, however, the ZBA grows and begins

S. T. Chui, V. N. Ryzhov, E. E. Tareyeva

The phase separation and vortex states in two-component Bose-Einstein condensate consisting of $|F=1,m_f=-1>$ and $|2,1>$ internal spin states of $^{87}Rb$ atoms are considered in the framework of Thomas-Fermi approximation. It is shown that in nonrotating system the atoms in the state $|1,-1>$ form a shell about the atoms in the state $|2,1>$. The critical

P. Wrobel, R. Eder

Using variational trial wave function based on the string picture we study the motion of a single mobile hole in the stripe phase of the doped antiferromagnet. The holes within the stripes are taken to be static, the undoped antiferromagnetic domains in between the hole stripes are assumed to have alternating staggered magnetization, as is suggested by neutr

Anders W. Sandvik, Rajiv R. P. Singh

We use quantum Monte Carlo simulations and numerical analytic continuation to study high-energy spin excitations in the two-dimensional S=1/2 Heisenberg antiferromagnet at low temperature. We present results for both the transverse and longitudinal dynamic spin structure factor S(q,w) at q=(pi,0) and (pi/2,pi/2). Linear spin-wave theory predicts no dispersio

V. A. Yurovsky, A. Ben-Reuven, P. S. Julienne, C. J. Williams

In experiments conducted recently at MIT on Na Bose-Einstein condensates [S. Inouye et al, Nature 392, 151 (1998); J. Stenger et al, Phys. Rev. Lett. 82, 2422 (1999)], large loss rates were observed when a time-varying magnetic field was used to tune a molecular Feshbach resonance state near the state of a pair of atoms in the condensate. A collisional deact

Takashi Shimada, Teruyoshi Murakami, Satoshi Yukawa, Keiji Saito

Heat conduction phenomena are studied theoretically using computer simulation. The systems are crystal with nonlinear interaction, and fluid of hard-core particles. Quasi-one-dimensional system of the size of $L_x\times L_y\times L_z(L_z\gg L_x,L_y)$ is simulated. Heat baths are put in both end: one has higher temperature than the other. In the crystal case,

Abhijit Kar Gupta, Dietrich Stauffer

The Social Percolation model recently proposed by Solomon et al. is studied on the Ising correlated inhomogeneous network. The dynamics in this is studied so as to understand the role of correlations in the social structure. Thus the possible role of the structural social connectivity is examined.

A. C. C. Coolen

A lecture notes style review of the non-equilibrium statistical mechanics of recurrent neural networks with discrete and continuous neurons (e.g. Ising, graded-response, coupled-oscillators). To be published in the Handbook of Biological Physics (North-Holland). Accompanied by a similar review (part I) dealing with the statics.

A. C. C. Coolen

A lecture notes style review of the equilibrium statistical mechanics of recurrent neural networks with discrete and continuous neurons (e.g. Ising, coupled-oscillators). To be published in the Handbook of Biological Physics (North-Holland). Accompanied by a similar review (part II) dealing with the dynamics.

Toshimasa Fujisawa, Yoshiro Hirayama

Radio-frequency (rf)- operated single-electron transistors (SETs) are high-sensitivity, fast-response electrometers, which are valuable for developing new insights into single-charge dynamics. We investigate high-frequency (up to 1 MHz) charge noise in an AlGaAs/GaAs quantum dot using a transmission-type rf-SET technique. The electron capture and emission ki

V. L. Golo, E. I. Kats, Yu. M. Yevdokimov

We suggest that the DNA molecules could form the cholesteric phase owing to an interaction mediated by the network of the hydrogen bonds (H-network) in the solvent. The model admits of the dependence of the optical activity of the solution on the concentration of the PEG, and the change in the sense of the cholesteric twist due to the intercalation by the da

Oded Farago, Yacov Kantor

We study the elastic properties of phantom networks of Gaussian and nearly-Gaussian springs. We show that the stress tensor of a Gaussian network coincides with the conductivity tensor of an equivalent resistor network, while its elastic constants vanish. We use a perturbation theory to analyze the elastic behavior of networks of slightly non-Gaussian spring

I. O. Kulik, H. Boyaci, Z. Gedik

Superconductivity in small metallic specimens is studied with regard to the size dependence of the &#34;parity gap&#34; (Delta_P), a parameter distinguishing between the energy of even and odd number of electrons in the granule. Delta_P is shown to be an increasing function of level spacing delta. The energy gap of superconductor Delta, on the other hand, de

Ari Buchalter, Raul Jimenez, Marc Kamionkowski

We investigate the effects of a variety of ingredients that must enter into a realistic model for disk-galaxy formation, focusing primarily on the Tully-Fisher (TF) relation and its scatter in several wavebands. Our main findings are: (a) the slope, normalization, and scatter of the TF relation across various wavebands is determined {\em both} by halo proper

Vicent Quilis, Ben Moore, Richard Bower

We present the first 3-dimensional high resolution hydro-dynamical simulations of the interaction between the hot ionised intra-cluster medium and the cold interstellar medium of spiral galaxies. Ram pressure and turbulent/viscous stripping removes 100% of the atomic hydrogen content of luminous galaxies like the Milky Way within 100 million years. These mec

Roger A. Chevalier

A plausible model for the Crab Nebula is one in which a particle dominated, highly relativistic wind from the pulsar passes through a shock front in which the particles attain a power law energy distribution. The electrons and positrons lose energy radiating synchrotron emission. Here, a one zone version of the model is developed and applied to observations

Roger A. Chevalier

There is increasing evidence that low mass stars with circumstellar disks can be born close to massive stars, in some cases within tenths of a pc. If the disks have lifetimes greater than those of the more massive stars, they are exposed to the radiation fields and gas flows from the late evolutionary phases and supernovae of the massive stars. The fast flow

Yuri Levin, Greg Ushomirsky

R-modes in neutron stars with crusts are damped by viscous friction at the crust-core boundary. The magnitude of this damping, evaluated by Bildsten and Ushomirsky (BU) under the assumption of a perfectly rigid crust, sets the maximum spin frequency for a neutron star spun up by accretion in a Low-Mass X-ray binary (LMXB). In this paper we explore the mechan

David A. Thilker, Robert Braun, Rene A. M. Walterbos

We have developed a robust, automated method, hereafter designated HIIphot, which enables accurate photometric characterization of HII regions while permitting genuine adaptivity to irregular source morphology. HIIphot utilizes object-recognition techniques to make a first guess at the shapes of all sources then allows for departure from such idealized ``see

R. L. Akeson, D. R. Ciardi, G. T. van Belle, M. J. Creech-Eakman

We present infrared observations of four young stellar objects using the Palomar Testbed Interferometer (PTI). For three of the sources, T Tau, MWC 147 and SU Aur, the 2.2 micron emission is resolved at PTI&#39;s nominal fringe spacing of 4 milliarcsec (mas), while the emission region of AB Aur is over-resolved on this scale. We fit the observations with sim

Richard J. Rand

We present key results from deep spectra of the Diffuse Ionized Gas (DIG) halo of the edge-on galaxy NGC 5775. [NII]6583 has been detected up to about z=13 kpc above the plane in one of two vertically oriented long slits -- making this the spiral galaxy with the greatest spectroscopically detected halo extent in emission. Key diagnostic line ratios have been

D. Londish, B. J. Boyle, D. J. Schade

We present a new determination of the optical luminosity function (OLF) of active galactic nuclei (AGN) at low redshifts (z<0.15) based on Hubble Space Telescope (HST) observations of X-ray-selected AGN. The HST observations have allowed us to derive a true nuclear luminosity function for these AGN. The resulting OLF illustrates a two-power-law form similar

R. X. Xu, Bing Zhang, G. J. Qiao

The possibility and the implications of the idea, that pulsars are born as strange stars, are explored. Strange stars are very likely to have atmospheres with typical mass of $\sim 5\times 10^{-15}M_\odot$ but bare polar caps almost throughout their lifetimes, if they are produced during supernova explosions. A direct consequence of the bare polar cap is tha

A. Cimatti, D. Villani, L. Pozzetti, S. di Serego Alighieri

We present the results of a K-band imaging survey of 40 arcmin^{2} in fields around 14 radio-loud AGN (6 radio galaxies and 8 quasars) with z>1.5. The survey, 80% complete to K<19.2 and complemented by R-band imaging, aimed at investigating whether extremely red objects (EROs) are present in excess around high-z AGN, and to study the environment of z>1.5 rad

David R. Alves, Cailin A. Nelson

The rotation of the disk of the Large Magellanic Cloud (LMC) is derived from the radial velocities of 422 carbon stars. New aspects of this analysis include the propagation of uncertainties in the LMC proper motion with a Monte Carlo, and a self-consistent modeling of the rotation curve and disk kinematics. The rotation curve is well fit by a truncated, fini

Peter Coles, Lung-Yih Chiang

The local Universe displays a rich hierarchical pattern of galaxy clusters and superclusters. The early Universe, however, was almost smooth, with only slight &#39;ripples&#39; seen in the cosmic microwave background radiation. Models of the evolution of structure link these observations through the effect of gravity, because the small initially overdense fl

Kiran Jain, S. C. Tripathy, A. Bhatnagar

We have analysed the recently available GONG p-mode frequencies and splitting coefficients for a period of three and half years, including the rapidly rising phase of solar cycle 23. The analysis of mean frequency shift with different activity indices shows that the shift is equally correlated with both magnetic and radiative indices. During the onset of the

S. Ettori, S. Bardelli, S. De Grandi, S. Molendi

We present a combined analysis of the BeppoSAX and ROSAT PSPC observation of the cluster of galaxies A3562, a massive member of the core of the Shapley Supercluster. With a complex and interacting structure composed from two groups of galaxies and A3558 to the West, the surface brightness of A3562 shows excess in the sectors to East and South when compared w

Arnon Dar

In a recent letter [1] with the same title, Farrar and Piran offered an explanation for the near isotropy of the arrival directions [2] of ultrahigh energy cosmic rays (UHECRs) and the apparent absence [3] of the so called `GZK cutoff&#39; in their spectrum around $10^{20}$ eV due to pion photoproduction on the cosmic background radiation (CMB) that was pred

Cesario Lia, Giovanni Carraro, Paolo Salucci

Using N-body/hydrodynamical simulations which include prescriptions for Star Formation, Feed-Back and Chemical Evolution, we explore the interaction between baryons and Dark Matter at galactic scale. The N-body simulations are performed using a Tree-SPH code that follows the evolution of individual DM halos inside which stars form from cooling gas, and evolv

K. Tsinganos, S. Bogovalov

We resolve the paradox that although magnetic collimation of an isotropic solar wind results in an enhancement of its proton flux along the polar directions, several observations indicate a wind proton flux peaked at the equator. To that goal, we solve the full set of the time-dependent MHD equations describing the axisymmetric outflow of plasma from the mag

Andreas Burkert, Peter Bodenheimer

The rotational properties of centrally condensed, turbulent molecular cloud cores with velocity fields that are characterized by Gaussian random fields are investigated. It is shown that the observed line width-size relationship can be reproduced if the velocity power spectrum is a power-law with P(k)=k**n and n=-3 to -4. The line-of-sight velocity maps of t

M. Matsuura, I. Yamamura, H. Murakami, T. Onaka

Results of an SiO maser survey for the late-type stars selected by the IRTS (Infrared Telescope in Space) are presented. We have detected SiO J=1-0, v=1 and/or v=2 lines in 27 stars out of 59 stars. The maser intensity increases with the depth of the H2O absorption in the infrared spectra and redness of the 2.2 and 12 micron color. The column densities of th

David G. Monet, Matthew D. Fisher, James Liebert, Blaise Canzian

We have conducted a search for new stars of high proper motion ($\geq$0.4 arcsec yr$^{-1}$) using POSS II fields for which an extra IIIaF (red) plate of good quality exists, along with useable IIIaJ (blue) and IV-N (infrared) plates taken at epochs differing by a minimum of 1.5 years. Thirty-five fields at Galactic latitudes $|b| \geq$ 20$^o$ were measured,

Hajime Susa, Masayuki Umemura

Based upon a novel paradigm of the galaxy formation under UV background, the evolutionary bifurcation of pregalactic clouds is confronted with observations on elliptical and spiral galaxies. The theory predicts that the dichotomy between the dissipational and dissipationless galaxy formation stems from the degree of self-shielding from the UV background radi

Will Saunders, Kenton D&#39;Mellow, Helen Valentine, Brent Tully

We summarise results for the predicted density and peculiar velocity fields from the PSCz survey. We have used a generalisation of the Path Interchange Zeldovich Approximation to determine the velocity field; the most remarkable feature being a coherent large-scale flow along the baseline connecting the Local Supercluster, Centaurus and the Shapley Concentra

Youjun Lu, Tinggui Wang

We compile the multi-band spectral energy distribution (SED) of Seyfert 1 galaxy NGC4593, and investigate its optical-to-ultraviolet (OUV) continuum and iron Kαline profile. No strong ``big blue bump&#39;&#39; is found in OUV band. The iron Kαline profile is not as broad as expected from a disk which extends down to the last stable orbit. Both of them can be