January 2006 arXiv papers — page 37

V. Anissimov, A. Alemberti

This work presents a numerical simulation using CFX 4.4 of the Energy Amplifier Experimental Facility (X-ADS) downcomer channel. The simulation is focused on the Steady-State Analysis. The Intermediate Heat exchangers (IHX) of the X-ADS reference configuration are immersed in the lead-bismuth eutectic of the downcomer. Due to the absence of a physical separa

M. Bianco, I. Borjanovic, G. Cataldi, A. Cazzato

The main results of the quality assurance tests performed on the Resistive Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are reported and discussed. Since July 2004, about 270 RPC units has been certified at INFN Lecce site and delivered to CERN, for being integrated in the final muon station of the ATLAS barrel region. We show t

Masahiko Hase, Ayako Yamada, Tsutomu Hamada, Kenichi Yoshikawa

When a cell-sized water droplet, with a diameter of several tens of micro meter, is placed in oil containing phospholipids, a stable cell-sized vesicle is spontaneously formed as a water-in-oil phospholipid emulsion (W/O CE) with a phospholipid monolayer. We transferred the lipid vesicle thus formed in the oil phase to the water phase across the water/oil in

L. G. Moretto, K. A. Bugaev, J. B. Elliott, L. Phair

This is a note intended to complement our paper (nucl-th/0504010) and addressed to the attention of QGP workers interested in bag models, Hagedorn spectra, and the like. It tries to show that with a Hagedorn-like experimental spectrum the partition function can not be calculated and that a canonical description derived for the microcanonical ensemble exists

Erik Johnson

The measured elliptic flow (v2) of identified particles as a function of pT and centrality at RHIC suggests the created medium in Au+Au collisions achieves early local thermal equilibrium that is followed by hydrodynamic expansion. It is not known if the eta dependence on v2 is a general feature of elliptic flow or reflects other changes in the particle spec

B. K. Nayak, U. Garg, M. Hedden, M. Koss

The strength distribution of the isoscalar giant dipole resonance (ISGDR) in $^{58}$Ni has been obtained over the energy range 10.5--49.5 MeV via extreme forward angle scattering (including 0$^{\circ}$) of 386 MeV $α$ particles. We observe a ``bi-modal&#39;&#39; ${E1}$ strength distribution for the first time in an A $<$ 90 nucleus. The observed ISGDR streng

Eduardo G. Altmann, Adilson E. Motter, Holger Kantz

We investigate the dynamics of chaotic trajectories in simple yet physically important Hamiltonian systems with non-hierarchical borders between regular and chaotic regions with positive measures. We show that the stickiness to the border of the regular regions in systems with such a sharply divided phase space occurs through one-parameter families of margin

Oksana Ye. Hentosh

We obtain via Bäcklund transformation the Hamiltonian representation for a Lax type nonlinear dynamical system hierarchy on a dual space to the Lie algebra of super-integral-differential operators of one anticommuting variable, extended by evolutions of the corresponding spectral problem eigenfunctions and adjoint eigenfunctions, as well as for the hierarchi

Yulia Karpeshina, Young-Ran Lee

We consider a polyharmonic operator $H=(-Δ)^l+V(x)$ in dimension two with $l\geq 6$ and a limit-periodic potential $V(x)$. We prove that the spectrum of $H$ contains a semiaxis and there is a family of generalized eigenfunctions at every point of this semiaxis with the following properties. First, the eigenfunctions are close to plane waves $e^{i< \vec k,\ve

David W. Farmer, Mark Yerrington

We give a precise measure of the rate at which repeated differentiation of a random trigonometric polynomial causes the roots of the function to approach equal spacing. This can be viewed as a toy model of crystallization in one dimension. In particular we determine the asymptotics of the distribution of the roots around the crystalline configuration and fin

Mathew D. Rogers

We prove several identities relating three-variable Mahler measures to integrals of inverse trigonometric functions. After deriving closed forms for most of these integrals, we obtain ten explicit formulas for three-variable Mahler measures. Several of these results generalize formulas due to Condon and Lalín. As a corollary, we also obtain three $q$-series

Pietro Poggi-Corradini

There is a universal constant $0<r_0<1$ with the following property. Suppose that $f$ is an analytic function on the unit disk $\D$, and suppose that there exists a constant $M>0$ so that the Euclidean area, counting multiplicity, of the portion of $f(\D)$ which lies over the disk $D(f(0),M)$, centered at $f(0)$ and of radius $M$, is strictly less than the a

Thomas Kahl

Algebraic topological methods have been used successfully in concurrency theory, the domain of theoretical computer science that deals with distributed computing. L. Fajstrup, E. Goubault, and M. Raussen have introduced partially ordered spaces (pospaces) as a model for concurrent systems. In this paper it is shown that the category of pospaces under a fixed

Diego Dominici

We analyze the Hermite polynomials $H_{n}(x)$ and their zeros asymptotically, as $n\to\infty.$ We obtain asymptotic approximations from the differential-difference equation which they satisfy, using the ray method. We give numerical examples showing the accuracy of our formulas.

Tomaš Kepka, Michael K. Kinyon, J. D. Phillips

In math.GR/0510298, we showed that every loop isotopic to an F-quasigroup is a Moufang loop. Here we characterize, via two simple identities, the class of F-quasigroups which are isotopic to groups. We call these quasigroups FG-quasigroups. We show that FG-quasigroups are linear over groups. We then use this fact to describe their structure. This gives us, f

Sergei Shadrin, Dimitri Zvonkine

Witten&#39;s top Chern class is a particular cohomology class on the moduli space of Riemann surfaces endowed with r-spin structures. It plays a key role in Witten&#39;s conjecture relating to the intersection theory on these moduli spaces. Our first goal is to compute the integral of Witten&#39;s class over the so-called double ramification cycles in genus

Dan Yasaki

Let X=Gamma\G/K be an arithmetic quotient of a symmetric space of non-compact type. In the case that G has Q-rank 1, we construct Gamma-equivariant deformation retractions of D=G/K onto a set D_0. We prove that D_0 is a spine, having dimension equal to the virtual cohomological dimension of Gamma. In fact, there is a (k-1)-parameter family of such deformatio

Dan Yasaki

Let Gamma\D be an arithmetic quotient of a symmetric space of non-compact type. A spine D_0 is a Gamma-equivariant deformation retraction of D with dimension equal to the virtual cohomological dimension of Gamma. We explicitly construct a spine for the case of Gamma=SU(2,1;Z[i]). The spine is then used to compute the cohomology of Gamma\D with various local

Ping Wong Ng, Wilhelm Winter

We show that finitely generated subhomogeneous C*-algebras have finite decomposition rank. As a consequence, any separable ASH C*-algebra can be written as an inductive limit of subhomogeneous C*-algebras each of which has finite decomposition rank. It then follows from work of H. Lin and of the second named author that the class of simple unital ASH algebra

Emily Burgunder

An infinite magmatic bialgebra is a vector space endowed with an n-ary operation, and an n-ary cooperation, for each n, verifying some compatibility relations. We prove a rigidity theorem, analogue to the Hopf-Borel theorem for commutative bialgebras: any connected infinite magmatic bialgebra is of the form $Mag^\infty(Prim H)$, where $Mag^\infty(V)$ is the

Marcin Bobienski

A nonstandard (maximal) inclusion SO(3) in SO(5) associated with the irreducible representation ρ_5 of SO(3) in R^5 is considered. The topological obstructions for admitting the SO(3) structure on the frame bundle over 5-manifold are investigated. The necessary and sufficient conditions are formulated.

Jean-Michel Billiot, Jean-François Coeurjolly, Rémy Drouilhet

This paper is devoted to the estimation of a vector parametrizing an energy function associated to some &#34;Nearest-Neighbours&#34; Gibbs point process, via the pseudo-likelihood method. We present some convergence results concerning this estimator, that is strong consistency and asymptotic normality, when only a single realization is observed. Sufficient c

D. Frettlöh

The nature of this paper is twofold: On one hand, we will give a short introduction and overview of the theory of model sets in connection with nonperiodic substitution tilings and generalized Rauzy fractals. On the other hand, we will construct certain Rauzy fractals and a certain substitution tiling with interesting properties, and we will use a new approa

Vladimir Kondratiev, Vladimir Maz&#39;ya, Mikhail Shubin

We establish new necessary and sufficient conditions for the discreteness of spectrum and strict positivity of magnetic Schrödinger operators with a positive scalar potential. They extend earlier results by Maz&#39;ya and Shubin (2005), which were obtained in case when there is no magnetic field. We also derive two-sided estimates for the bottoms of spectrum

Aaron Lauve

We show that the Yangian Yn over gl_n possesses some features of the ring of regular functions on GL_n. In particular, we use the theory of quasideterminants to construct noncommutative flags associated to Yn. In so doing, a class of comodule algebras Fl(γ) for Yn (viewed as C[GL_n]) is revealed. As in the classic case, these flag algebras are related to the

Lipika Deka

The problem of finding fermionic formulas for the many generalizations of Kostka polynomials and for the characters of conformal field theories has been a very exciting research topic for the last few decades. In this dissertation we present new fermionic formulas for the unrestricted Kostka polynomials extending the work of Kirillov and Reshetikhin. We also

Dan Abramovich

These are lecture notes of a C.I.M.E. course I gave at Cetraro, June 6-11 2005. The theory described is the version of Chen-Ruan&#39;s Gromov-Witten theory of orbifolds developed by Graber, Vistoli and me in the algebraic setting, but with introduction beginning in Kontsevich&#39;s formula on rational plane curves and through Gromov-Witten theory of algebrai

Florian Bertrand

We construct some lift of an almost complex structure to the cotangent bundle, using a connection on the base manifold. This generalizes the complete lift defined by I.Sato and the horizontal lift introduced by K.Yano and S.Ishihara. We study some geometric properties of this lift and its compatibility with symplectic forms on the cotangent bundle.

Wilhelm Winter

We show that, if A is a separable simple unital C*-algebra which absorbs the Jiang-Su algebra Z tensorially and which has real rank zero and finite decomposition rank, then A is tracially AF in the sense of Lin, without any restriction on the tracial state space. As a consequence, the Elliott conjecture is true for the class of C*-algebras as above which, ad

R. de la Breteche, T. D. Browning

In this paper the height zeta function associated to a certain singular del Pezzo surface of degree four is studied. If $U$ denotes the open subset formed by deleting the unique line from this surface, then an asymptotic formula for the number of rational points of bounded height on $U$ is established which verifies the Manin conjecture.

Florent Benaych-Georges

We prove that a probability measure on the real line has a moment of order p (even integer), if and only if its R-transform admits a Taylor expansion with p terms. We also prove a weaker version of this result when p is odd. Then, we apply this to prove that a probability measure whose R-transform extends analytically to a ball with center zero is compactly

Aaron Lauve

We demonstrate a passage from the &#34;quasi-Plucker coordinates&#34; of Gelfand and Retakh, to the quantum Plucker coordinates built from q-generic matrices. In the process, we rediscover the defining relations of the quantum Grassmannian of Taft and Towber and provide that algebra with more concrete geometric origins.

Adrian Vasiu

We prove that an $F$-crystal $(M,\vph)$ over an algebraically closed field $k$ of characteristic $p>0$ is determined by $(M,\vph)$ mod $p^n$, where $n\ge 1$ depends only on the rank of $M$ and on the greatest Hodge slope of $(M,\vph)$. We also extend this result to triples $(M,\vph,G)$, where $G$ is a flat, closed subgroup scheme of ${\bf GL}_M$ whose generi

J. M. Carmona, J. L. Cortes

The possibility to have a deviation from relativistic quantum field theory requiring to go beyond effective field theories is discussed. A few recent attempts to go in this direction both at the theoretical and phenomenological levels are briefly reviewed.

Levent Akant

We show that in the high temperature limit the partition function of a matrix model is localized on certain shells in the phase space where on each shell the classically conjugate matrix variables obey the canonical commutation relations. The result is obtained by applying the nonabelian equivariant localization principle to the partition function of a matri

Holger B. Nielsen, Masao Ninomiya

The universe is certainly not yet in total thermodynamical equilibrium,so clearly some law telling about special initial conditions is needed. A universe or a system imposed to behave periodically gets thereby required ``initial conditions&#34;. Those initial conditions will \underline{not} look like having already suffered the heat death, i.e. obtained the

El Hassan Saidi

Using a two component $SL(2) $ isospinor formalism, we study the link between conifold $T^{\ast}\mathbb{S}^{3}$ and q-deformed non commutative holomorphic geometry in complex four dimensions. Then, thinking about conifold as a projective complex three dimension hypersurface embedded in non compact $WP^{5}(1,-1,1,-1,1,-1) $ space and using conifold local isom

Marvin Weinstein

Adaptive perturbation is a new method for perturbatively computing the eigenvalues and eigenstates of quantum mechanical Hamiltonians that heretofore were not believed to be obtainable by such methods. The novel feature of adaptive perturbation theory is that it decomposes a given Hamiltonian, $H$, into an unperturbed part and a perturbation in a way which e

Svjetlana Fajfer, Jernej Kamenik

Motivated by the recent extraction of the helicity amplitudes for the D+ -> K*0bar mu+ nu decay, done by the FOCUS collaboration, we determine helicity amplitudes for the D+ -> K*0bar l nu, D+ -> rho0 l nu and Ds -> phi l nu semileptonic decays using the knowledge of the relevant form factors. The vector and axial form factors for D -> V l nu decays are para

A. T. Alan, A. T. Tasci, N. Karagoz

We investigate the single and pair production of new heavy leptons via string inspired $E_{6}$ model at future linear colliders. Signal and corresponding backgrounds for these leptons are studied. We have found that single production of heavy leptons is more relevant than that of pair production, as expected. For a maximal mixing value of 0.1, the upper mass

Peter Wolf, Frederic Chapelet, Sebastien Bize, Andre Clairon

We report on a new experiment that tests for a violation of Lorentz invariance (LI), by searching for a dependence of atomic transition frequencies on the orientation of the spin of the involved states (Hughes-Drever type experiment). The atomic frequencies are measured using a laser cooled $^{133}$Cs atomic fountain clock, operating on a particular combinat

M. Bluhm, B. Kampfer

Our quasi-particle model is compared with recent lattice QCD data at finite temperature and baryon number density with emphasis on the coefficients in the Taylor series expansion of thermodynamic observables. The inclusion of static critical end point effects into the equation of state is discussed.

Fumiko Okiharu, Hideo Suganuma, Toru T. Takahashi, Takumi Doi

We study multi-quark (3Q,4Q,5Q) systems in lattice QCD. We perform the detailed studies of multi-quark potentials in lattice QCD to clarify the inter-quark interaction in multi-quark systems. We find that all the multi-quark potentials are well described by the OGE Coulomb plus multi-Y-type linear potential, i.e., the multi-Y Ansatz. For multi-quark systems,

David H. Miller

Results are presented on Charmonium using data collected with the CLEO III and CLEO-c detectors at the Psi(2S) and Psi(3770). Measurements include, the first observation of the hc(1P1) state, the electronic widths of the J/Psi and Psi(2S), the two photon width of the Chic2 and hadronic decays of the Psi(2S).

Dan N. Vollick

A modified gravitational action is considered which involves the quantity $F_{μν}=\partial_μΓ_ν-\partial_νΓ_μ$, where $Γ_μ=Γ^α_{μα}$. Since $Γ_μ$ transforms like a U(1) gauge field under coordinate transformations terms such as $F^{μν}F_{μν}$ are invariant under coordinate transformations. If such a term is added to the usual gravitational action the resulti

Ignazio Ciufolini, Erricos Pavlis

In this paper, we provide a detailed description of our recent analysis and determination of the frame-dragging effect obtained using the nodes of the satellites LAGEOS and LAGEOS 2, in reply to the paper &#34;On the reliability of the so-far performed tests for measuring the Lense-Thirring effect with the LAGEOS satellites&#34; by L. Iorio

Joan Sola, Hrvoje Stefancic

A cosmological constant, Lambda, is the most natural candidate to explain the origin of the dark energy (DE) component in the Universe. However, due to experimental evidence that the equation of state (EOS) of the DE could be evolving with time/redshift (including the possibility that it might behave phantom-like near our time) has led theorists to emphasize

Eleftherios Papantonopoulos

We discuss cosmological models in six-dimensional spacetime. For codimension-1 branes, we consider a (4+1) braneworld model and discuss its cosmological evolution. For codimension-2 branes, we consider an infinitely thin conical braneword model in the presence of an induced gravity term on the brane and a Gauss-Bonnet term in the bulk. We discuss the cosmolo

Anant Sahai, Sanjoy Mitter

We review how Shannon&#39;s classical notion of capacity is not enough to characterize a noisy communication channel if the channel is intended to be used as part of a feedback loop to stabilize an unstable scalar linear system. While classical capacity is not enough, another sense of capacity (parametrized by reliability) called ``anytime capacity&#39;&#39;

Y. Zhong, F. Alajaji, L. L. Campbell

We investigate the computation of Csiszar&#39;s bounds for the joint source-channel coding (JSCC) error exponent, E_J, of a communication system consisting of a discrete memoryless source and a discrete memoryless channel. We provide equivalent expressions for these bounds and derive explicit formulas for the rates where the bounds are attained. These equiva

J-Y Ke, Y. Yao

In this paper we propose some new measures of language development using network analyses, which is inspired by the recent surge of interests in network studies of many real-world systems. Children&#39;s and care-takers&#39; speech data from a longitudinal study are represented as a series of networks, word forms being taken as nodes and collocation of words

Rolf Schilling

We investigate a classical lattice system with $N$ particles. The potential energy $V$ of the scalar displacements is chosen as a $ϕ^4$ on-site potential plus interactions. Its stationary points are solutions of a coupled set of nonlinear equations. Starting with Aubry&#39;s anti-continuum limit it is easy to establish a one-to-one correspondence between the

E. J. Nicol, J. P. Carbotte

Recently several works have focused on the intrinsic nonlinear current in passive microwave filters as a tool for identifying d-wave order parameter symmetry in the high Tc cuprates. Evidence has been found for d-wave pairing in YBCO and further work has ensued. Most of the theoretical work has been limited to low temperature because it has not included the

A. Krimmel, J. Strempfer, B. Bohnenbuck, B. Keimer

We report on a detailed single crystal x-ray diffraction study of the unconventional spin-Peierls compound TiOCl. The intermediate phase of TiOCl is characterized by an incommensurate modulation which is virtually identical to that recently found in the homologue compound TiOBr. The first order phase transition between the spin-Peierls ground state and the i

Claudio Furtado, A. M. de M. Carvalho, C. A. de Lima Ribeiro

In this work we investigate quasiparticles in the background of defects in solids using the geometric theory of defects. We use the parallel transport matrix to study the Aharonov-Bohm effect in this background. For quasiparticles moving in this effective medium we demonstrate an effect similar to the gravitational Aharonov- Bohm effect. We analyze this effe

E. M. F. Curado, A. Plastino

We focus attention on some particular thermodynamic relations (PTR). Using information theory concepts we show that, for a reversible process, microscopic considerations related to these PTR make the concomitant informational contents of the first and second laws equivalent. The pertinent demonstration is obtained when trying to ascertain the corresponding e

R. L. C. Vink

The critical behavior of the Widom-Rowlinson mixture [J. Chem. Phys. 52, 1670 (1970)] is studied in d=3 dimensions by means of grand canonical Monte Carlo simulations. The finite size scaling approach of Kim, Fisher, and Luijten [Phys. Rev. Lett. 91, 065701 (2003)] is used to extract the order parameter and the coexistence diameter. It is demonstrated that t

Jaroslaw Piasecki, Rodrigo Soto

We consider a non-interacting one-dimensional gas accelerated by a constant and uniform external field. The energy absorbed from the field is transferred via elastic collisions to a bath of scattering obstacles. At gas-obstacle encounters the particles of the gas acquire a fixed kinetic energy. The approach to the resulting stationary state is studied within

Gregory Schehr, Satya N. Majumdar

We study the probability density function $P(h_m,L)$ of the maximum relative height $h_m$ in a wide class of one-dimensional solid-on-solid models of finite size $L$. For all these lattice models, in the large $L$ limit, a central limit argument shows that, for periodic boundary conditions, $P(h_m,L)$ takes a universal scaling form $P(h_m,L) \sim (\sqrt{12}w

G. Reiter, C. Burnham, D. Homouz, P. M. Platzman

The momentum distribution of the protons in ice Ih, ice VI, high density amorphous ice and water in carbon nanotubes at low temperatures has been measured using deep inelastic neutron scattering. We find that the momentum distribution for the water in the nanotubes is qualitatively unlike that in any other phase of water or ice. The kinetic energy of the pro

A. B. Shick, F. Maca, J. Masek, T. Jungwirth

Tunneling anisotropic magnetoresistance (TAMR) effect, discovered recently in (Ga,Mn)As ferromagnetic semiconductors, arises from spin-orbit coupling and reflects the dependence of the tunneling density of states in a ferromagnetic layer on orientation of the magnetic moment. Based on ab initio relativistic calculations of the anisotropy in the density of st

Shinya Katayama, Akito Kobayashi, Yoshikazu Suzumura

The electric conductivity which reveals the zero gap semiconducting (ZGS) state has been investigated as the function of temperature $T$ and life time $τ$ in order to understand the ZGS state in quarter-filled $α$-(BEDT-TTF)$_2$I$_3$ salt with four sites in the unit cell. By treating $τ$ as a parameter and making use of the one-loop approximation, it is foun

Ireneusz Weymann, Jozef Barnas

Spin-dependent electronic transport in magnetic double-island devices is considered theoretically in the sequential tunneling regime. Electric current and tunnel magnetoresistance are analyzed as a function of the bias voltage and spin relaxation time in the islands. It is shown that the interplay of spin accumulation on the islands and charging effects lead

Ki-Seok Kim

We propose an effective Lagrangian for the continuous transition from the heavy fermion metal to the antiferromagnetic metal in an extended Kondo lattice model. Based on the slave-boson representation we introduce an additional new order parameter associated with difference of the chemical potential between conduction electrons $c_{iσ}$ and local spinons $f_

L D Tung

We report a novel feature of the temperature induced magnetization jump observed along the a-axis of the GdVO3 single crystal at temperature TM = 0.8 K. Below TM, the compound shows no coercivity and remanent magnetization indicating a homogenous antiferromagnetic structure. However, we will demonstrate that the magnetic state below TM is indeed history depe

A. Dominguez Folgueras, K. Maki

The symmetry of the superconducting order parameter in Bechgaard salts is still unknown, though the triplet pairing is well stablished by NMR data and large upper critical field. Here we examine the upper critical field of a few candidate superconductors within the standard formalism. The present analysis suggests strongly chiral f-wave superconductor somewh

C. A. M. dos Santos, C. J. V. Oliveira, M. S. da Luz, A. D. Bortolozo

A two-fluid model is proposed to describe the transport properties of granular superconductors. Using the resistively shunted junction model and some aspects of the two-level system theory, a statistical model is developed which takes into account the ratio between the number of normal and superconducting electrons carrying the applied current. The theoretic

Hiori Kino, Tsuyoshi Miyazaki

Within the framework of the density functional theory, we calculate the electronic structure of $α$-(BEDT-TTF)$_2$I$_3$ at 8K and room temperature at ambient pressure and with uniaxial strain along the $a$- and $b$-axes. We confirm the existence of anisotropic Dirac cone dispersion near the chemical potential. We also extract the orthogonal tight-binding par

Yoshiki Imai, Keitaro Sakurazawa, Tetsuro Saso

Anomalous metal-insulator transition observed in filled skutterudite CeOs$_4$Sb$_{12}$ is investigated by constructing the effective tight-binding model with the Coulomb repulsion between f electrons. By using the mean field approximation, magnetic susceptibilities are calculated and the phase diagram is obtained. When the band structure has a semimetallic c

Kazuhiko Kuroki

A review is given on theoretical studies concerning the pairing symmetry in organic superconductors. In particular, we focus on (TMTSF)$_2$X and $κ$-(BEDT-TTF)$_2$X, in which the pairing symmetry has been extensively studied both experimentally and theoretically. Possibilities of various pairing symmetry candidates and their possible microscopic origin are d

Thilo Stöferle, Henning Moritz, Christian Schori, Kenneth Günter

We report on the realization of a quantum degenerate atomic Fermi gas in an optical lattice. Fermi surfaces of noninteracting fermions are studied in a three-dimensional lattice. Using a Feshbach resonance, we observe a coupling of the Bloch bands in the strongly interacting regime.

Sheldon Goldstein, Joel L. Lebowitz, Roderich Tumulka, Nino Zanghi

It is well known that a system, S, weakly coupled to a heat bath, B, is described by the canonical ensemble when the composite, S+B, is described by the microcanonical ensemble corresponding to a suitable energy shell. This is true both for classical distributions on the phase space and for quantum density matrices. Here we show that a much stronger statemen

I. Rushkin, P. Oikonomou, L. P. Kadanoff, I. A. Gruzberg

Standard stochastic Loewner evolution (SLE) is driven by a continuous Brownian motion, which then produces a continuous fractal trace. If jumps are added to the driving function, the trace branches. We consider a generalized SLE driven by a superposition of a Brownian motion and a stable Levy process. The situation is defined by the usual SLE parameter, $κ$,

Miguel D. Costa, J. Viana Lopes, J. M. B. Lopes dos Santos

We present a model for the dynamics in energy space of multicanonical simulation methods that lends itself to a rather complete analytic characterization. The dynamics is completely determined by the density of states. In the \pm J 2D spin glass the transitions between the ground state level and the first excited one control the long time dynamics. We are ab

s Eye Collaboration

Air fluorescence measurements of cosmic ray energy must be corrected for attenuation of the atmosphere. In this paper we show that the air-showers themselves can yield a measurement of the aerosol attenuation in terms of optical depth, time-averaged over extended periods. Although the technique lacks statistical power to make the critical hourly measurements

Asantha Cooray

Conditional luminosity function (CLF) of dark matter halos supersedes simple models on the number of galaxies as a function of the halo mass, or the so-called halo occupation number, by assigning a luminosity distribution to those galaxies. Suggestions have now been made that both the clustering strength and properties of hosted galaxies of a given dark matt

Alexandre Roman-Lopes, Zulema Abraham

We report NIR broad and narrow band photometric observations in the direction of the IRAS17149-3916 source that reveal the presence of a young cluster of massive stars embedded in an HII region coincident with RCW121. These observations, together with published radio data, MSX and Spitzer images were used to determine some of the physical parameters of the r

C. Kevin Xu

This is a review talk on the UV and infrared selected galaxies. The central question addressed is: do UV and infrared surveys see the 2 sides of star formation of the same population, or star formation of 2 different populations? We first review the literature on the UV and IR selected galaxy samples, try to quantify the difference and overlaps between these

V. Coenda, H. Muriel, C. J. Donzelli, H. Quintana

We analyze photometric properties of 1384 cluster galaxies as a function of the normalized distance to cluster center. These galaxies were selected in the central region ($r/r_{200} \leq$ 0.8) of 14 southern Abell clusters chosen from the Southern Abell Cluster Redshifts Survey (SARS). For 507 of these galaxies we also obtained their luminosity profiles. We

C. Kevin Xu

Stephan&#39;s Quintet (SQ), discovered more than 100 years ago, is the most famous and well studied compact galaxy group. It has been observed in almost all wavebands, with the most advanced instruments including Spitzer, GALEX, HST, Chandra, VLA, and various large mm/submm telescopes/arrays such as the IRAM 30m and BIMA. The rich multi-band data reveal one

A. Leistra, A. Cotera, J. Liebert

We present near-infrared $J$, $H$, and $K$ images of four embedded stellar clusters in the Galaxy. We find a significant fraction of pre-main-sequence stars present in at least one of the clusters. For the clusters dominated by main-sequence stars, we determine the initial mass function (IMF) both by using the $K$ luminosity function and a global extinction

Bryan M. Gaensler, Patrick O. Slane

Pulsars steadily dissipate their rotational energy via relativistic winds. Confinement of these outflows generates luminous pulsar wind nebulae, seen across the electromagnetic spectrum in synchrotron and inverse Compton emission, and in optical emission lines when they shock the surrounding medium. These sources act as important probes of relativistic shock

M. E. Filho, P. D. Barthel, L. C. Ho

In order to determine the incidence of black hole accretion-driven nuclear activity in nearby galaxies, as manifested by their radio emission, we have carried out a high-resolution Multi-Element Radio-Linked Interferometer Network (MERLIN) survey of LINERs and composite LINER/H{\sc ii} galaxies from a complete magnitude-limited sample of bright nearby galaxi

C. Peroux, V. P. Kulkarni, J. Meiring, R. Ferlet

The metallicity in portions of high-redshift galaxies has been successfully measured thanks to the gas observed in absorption in the spectra of quasars, in the Damped Lyman-alpha systems (DLAs). Surprisingly, the global mean metallicity derived from DLAs is about 1/10th solar at 0<z<4 leading to the so-called ``missing-metals problem&#39;&#39;. In this paper

Thushara Pillai, Friedrich Wyrowski, Sean J. Carey, Karl M. Menten

Infrared Dark Clouds appear to be the long sought population of cold and dense aggregations with the potential of harbouring the earliest stages of massive star formation. Up to now there has been no systematic study on the temperature distribution, velocity fields, chemical and physical state toward this new cloud population. Knowing these properties is cru

A. Majczyna, J. Madej

We analyzed archival X-ray spectra of MXB 1728-34 obtained in 1996-99 by the Proportional Counter Array on board of the RXTE satellite. X-ray spectra were fitted to our extensive grids of model atmosphere spectra to determine the effective temperature T_eff on the neutron star surface, logarithm of surface gravity log(g), and the gravitational redshift z sim

Michael D. Audley, Fumiaki Nagase, Kazuhisa Mitsuda, Lorella Angelini

We report on two ASCA observations of the high-mass X-ray binary pulsar OAO 1657-415. A short observation near mid-eclipse caught the source in a low-intensity state, with a weak continuum and iron emission dominated by the 6.4-keV fluorescent line. A later, longer observation found the source in a high-intensity state and covered the uneclipsed through mid-

Jacco Th. van Loon, Iain McDonald, Joana M. Oliveira, A. Evans

We present 8-13 micron spectra of eight red giants in the globular cluster 47 Tucanae (NGC 104), obtained at the European Southern Observatory 3.6m telescope. These are the first mid-infrared spectra of metal-poor, low-mass stars. The spectrum of at least one of these, namely the extremely red, large-amplitude variable V1, shows direct evidence of circumstel

Takahiro Kudoh, Shantanu Basu

We use numerical simulations to study the effect of nonlinear MHD waves in a stratified, self-gravitating molecular cloud that is bounded by a hot and tenuous external medium. In a previous paper, we had shown the details of a standard model and studied the effect of varying the dimensionless amplitude. In this paper, we present the results of varying two ot

R. S. Levenhagen, N. V. Leister, J. Zorec, Y. Frémat

Fast rotation seems to be the mayor factor to trigger the Be phenomenon. Surface fast rotation can be favored by initial formation conditions, such as abundance of metals. We have observed 118 Be stars up to the apparent magnitudes V=9 mag. Models of fast rotating atmospheres and evolutionary tracks were used to interpret the stellar spectra and to determine

M. M. F. Vinicius, N. V. Leister, J. Zorec, R. S. Levenhagen

The Halpha line emission formation region in the circumstellar disc of alpha Eri is: a) extended with a steep outward matter density decline during low H$α$ emission phases; b) less extended with rather constant density distribution during the strong Halpha emission. The long-term variation of the Halpha emission has a 14-15 year cyclic B-Be phase transition

M. L. Arias, J. Zorec, Y. Frémat

Emission lines formed in the circumstellar envelopes of several type of stars can be modeled using first principles of line formation. We present simple ways of calculating line emission profiles formed in circumstellar envelopes having different geometrical configurations. The fit of the observed line profiles with the calculated ones may give first order e

J. Zorec, Y. Frémat, A. Domiciano De Souza

Using 2D models of rotating stars, the interferometric measurements of alpha Eri and its fundamental parameters corrected for gravitational darkening effects we infer that the star might have a core rotating 2.7 times faster than the surface. We explore the consequences on spectral lines produced by surface differential rotation combined with the effects due

J. Zorec, Y. Frémat, C. Martayan, L. Cidale

We show that Be stars belong to a high velocity tail of a single B-type star rotational velocity distribution in the MS. This implies that: 1) the number fraction N(Be)/N(Be+B) is independent of the mass; 2) Bn stars having ZAMS rotational velocities higher than a given limit might become Be stars.

J. A. Surace, Z. Wang, S. Willner, H. Smith

We present results from two mid-infrared imaging programs of ultraluminous infrared galaxies (ULIRGs) and fine-structure elliptical galaxies. The former are known to nearly all be recent mergers between two gas-rich spiral galaxies, while the latter are also believed to be even more aged merger remnants. An examination of these two classes of objects, which

Aya Bamba, Masaru Ueno, Hiroshi Nakajima, Koji Mori

We report on an {\it XMM-Newton} observation of the supernova remnant (SNR) \object{DEM L241} in the Large Magellanic Cloud. In the soft band image, the emission shows an elongated structure, like a killifish, with a central compact source. The compact source is point-like, and named as XMMU J053559.3$-$673509. The source spectrum is well reproduced with a p

Alexandre Roman-Lopes, Zulema Abraham

We report the discovery of a small cluster of massive stars embedded in a NIR nebula in the direction of the IRAS15411-5352 point source, which is related to the alleged planetary nebula W16-185. The majority of the stars present large NIR excess characteristic of young stellar objects and have bright counterparts in the Spitzer IRAC images; the most luminou

Nathan Smith

(abridged) The Carina Nebula (NGC 3372) is our richest nearby laboratory in which to study feedback through UV radiation and stellar winds from very massive stars during the formation of an OB association before supernova explosions have influenced the environment. This paper takes inventory of the combined effect from all the known massive stars that power

R. F. Gabbasov, M. A. Rodriguez-Meza, Jaime Klapp, Jorge L. Cervantes-Cota

The joint influence of numerical parameters such as the number of particles N, the gravitational softening length $ε$ and the time-step $Δt$ is investigated in the context of galaxy simulations. For isolated galaxy models we have performed a convergence study and estimated the numerical parameters ranges for which the relaxed models do not deviate significan

Jonathan Granot, Arieh Konigl, Tsvi Piran

According to current models, gamma-ray bursts (GRBs) are produced when the energy carried by a relativistic outflow is dissipated and converted into radiation. The efficiency of this process, $ε_γ$, is one of the critical factors in any GRB model. The X-ray afterglow light curves of Swift GRBs show an early stage of flat decay. This has been interpreted as r