December 2005 arXiv papers — page 27

E. Tomasi-Gustafsson, G. I. Gakh, C. Adamuscin

We suggest a simple phenomenological parametrization for all three deuteron electromagnetic form factors, and show that a good fit on the available data, with a minimal number of parameters, can be obtained. The present description of the deuteron electromagnetic structure is based on two components with different radii, one corresponding to two nucleons sep

Shujun Li

This paper focuses on an interesting phenomenon when chaos meets computers. It is found that digital computers are absolutely incapable of showing true long-time dynamics of some chaotic systems, including the tent map, the Bernoulli shift map and their analogues, even in a high-precision floating-point arithmetic. Although the results cannot directly genera

J. Cuevas, J. F. R. Archilla, B. Sánchez-Rey, F. R. Romero

In this paper a Frenkel--Kontorova model with a nonlinear interaction potential is used to describe a vacancy defect in a crystal. According to recent numerical results [Cuevas et al, Phys. Lett. A 315, 364 (2003)] the vacancy can migrate when it interacts with a moving breather. We study more thoroughly the phenomenology caused by the interaction of moving

R. P. Mondaini

The application of optimization techniques derived from the study of Euclidean full Steiner Trees to macromolecules like proteins is reported in the present work. We shall use the concept of Euclidean Steiner Ratio Function (SRF) as a good Lyapunov function in order to perform an elementary stability analysis.

V. P. Belavkin

A characterization of the unbounded stochastic generators of quantum completely positive flows is given. This suggests the general form of quantum stochastic adapted evolutions with respect to the Wiener (diffusion), Poisson (jumps), or general Quantum Noise. The corresponding irreversible Heisenberg evolution in terms of stochastic completely positive (CP)

P. J. Forrester

The $N$-particle free fermion state for quantum particles in the plane subject to a perpendicular magnetic field, and with doubly periodic boundary conditions, is written in a product form. The absolute value of this is used to formulate an exactly solvable one-component plasma model, and further motivates the formulation of an exactly solvable two-species C

Juerg Froehlich, B. Lars G. Jonsson, Enno Lenzmann

We study the nonlinear equation $i \partial_t ψ= (\sqrt{-Δ+ m^2} - m) ψ- ( |x|^{-1} \ast |ψ|^2 ) ψ$ on $\RR^3$, which is known to describe the dynamics of pseudo-relativistic boson stars in the mean-field limit. For positive mass parameters, $m > 0$, we prove existence of travelling solitary waves, $ψ(t,x) = e^{i t μ} \sol_{v}(x-vt)$, with speed $|v| < 1$, w

V. P. Belavkin

A characterisation of the generators of quantum stochastic cocycles of completely positive (CP) maps is given in terms of the complete dissipativity (CD) of its form-generator. The pseudo-Hilbert dilation of the stochastic form-generator and the pre-Hilbert dilation of the corresponding dissipator is found. The general form of the linear continuous structura

Elena Santopinto, Roelof Bijker, Francesco Iachello

We derive a general expression for the transformation brackets between the chains U(n+1) -> U(n) -> SO(n) and U(n+1) -> SO(n+1) -> SO(n).

A. Ballesteros, E. Celeghini, M. A. del Olmo

The two isomorphic Borel subalgebras of gl(n), realized on upper and lower triangular matrices, allow us to consider the gl(n) \opus t_n algebra as a self-dual Drinfeld double. Compatibility conditions impose the choice of an orthonormal basis in the Cartan subalgebra and fix the basis of gl(n). A natural Lie bialgebra structure on gl(n) is obtained, that of

François Nicoleau

We study an inverse scattering problem for a pair of Hamiltonians $(H(h), H\_0 (h))$ on $L^2 (\r^n)$, where $H\_0 (h) = -h^2 Δ$ and $H (h)= H\_0 (h) +V$, $V$ is a short-range potential with a regular behaviour at infinity and $h$ is the semiclassical parameter. We show that, in dimension $n \geq 3$, the knowledge of the scattering operators $S(h)$, $h \in ]0

Gavriel Segre

It is shown that the non-adiabatic Hannay&#39;s angle of an integrable non-degenerate classical hamiltonian dynamical system may be related to the Aharonov-Anandan phase it develops when it is looked mathematically as a quantum dynamical system.

R. G. Dolgoarshinnykh Steven P. Lalley

We exhibit a scaling law for the critical SIS stochastic epidemic: If at time 0 the population consists of square root N infected and N - square root N susceptible individuals, then when time and number currently infected are both scaled by square root N, the resulting process converges, for large N, to a diffusion process related to the Feller diffusion by

F. Reese Harvey, H. Blaine Lawson,, John Zweck

The theory of differential characters is developed completely from a de Rham - Federer viewpoint. Characters are defined as equivalence classes of special currents, called sparks, which appear naturally in the theory of singular connections. There are many different spaces of currents which yield the character groups. A multiplication of de Rham-Federer char

V. V. Bavula

Using the author&#39;s inversion formula for automorphisms of the Weyl algebras with polynomial coefficients and the bound on its degree a slightly shorter (algebraic) proof is given of the result of A. Belov-Kanel and M. Kontsevich that the Jacobian Conjecture implies the Dixmier Proplem. No originality is claimed.

T. Gannon

The Conway--Norton conjectures unexpectedly related the Monster with certain special modular functions (Hauptmoduls). Their proof by Borcherds et al was remarkable for demonstrating the rich mathematics implicit there. Unfortunately Moonshine remained almost as mysterious after the proof as before. In particular, a computer check - as opposed to a general co

Carlos Tomei, Luen-Chau Li

We establish the Liouville integrability of the differential equation $\dot S(t)= [N,S^2(t)],$ recently considered by Bloch and Iserles. Here, $N$ is a real, fixed, skew-symmetric matrix and $S$ is real symmetric. The equation is realized as a Hamiltonian vector field on a coadjoint orbit of a loop group, and sufficiently many commuting integrals are present

Francesco Bonechi, Maxim Zabzine

We construct the moduli spaces associated to the solutions of equations of motion (modulo gauge transformations) of the Poisson sigma model with target being an integrable Poisson manifold. The construction can be easily extended to a case of a generic integrable Lie algebroid. Indeed for any Lie algebroid one can associate a BF-like topological field theory

Tomáš Kepka, Michael Kinyon, J. D. Phillips

In math.GR/0510298, we showed that every F-quasigroup is linear over a special kind of Moufang loop called an NK-loop. Here we extend this relationship by showing an equivalence between the equational class of (pointed) F-quasigroups and the equational class corresponding to a certain notion of generalized module (with noncommutative, nonassociative addition

Yousuke Ohyama, Shoji Okumura

We will classify all rational transformations which change the confluent hypergeometric equations to linear equations of the Painleve type from the first to the fifth. We show such rational transformations correspond to almost all of algebraic solutions of the Painleve equations from the first to fifth up to the Backlund transformations.

Said El Marzguioui, Jan Wiegerinck

We prove that the pluri-fine topology on any open set $Ω$ in $\mathbb{C}^{n}$ is locally connected. This answers a question by Fuglede in [4]. See also Bedford [6].

Peter Major

This paper contains sharp estimates about the distribution of multiple random integrals of functions of several variables with respect to a normalized empirical measure, about the distribution of U-statistics and multiple Wiener-Ito integrals with respect to a white noise. It also contains good estimates about the supremum of appropriate classes of such inte

Franziska Heinloth

We consider zeta functions with values in the Grothendieck ring of Chow motives. Investigating the lambda-structure of this ring, we deduce a functional equation for the zeta function of abelian varieties. Furthermore, we show that the property of having a rational zeta function satisfying a functional equation is preserved under products.

Margherita Barile

We show that the number of elements generating a squarefree monomial ideal up to radical can always be bounded above in terms of the number of its minimal monomial generators and the maximal height of its minimal primes.

Sacha C. Blumen

We prove two generalisations of the Binomial theorem that are also generalisations of the q-binomial theorem. These generalisations arise from the commutation relations satisfied by the components of the co-multiplications of non-simple root vectors in the quantum superalgebra U_{q}(osp(1|2n)).

Stephan Baier

Extending a method of D. Wolke, we establish a general result on the large sieve with sparse sets S of moduli which are in a sense well-distributed in arithmetic progressions. We then use this result together with Fourier techniques to obtain large sieve bounds for the case when S consists of squares. These bounds improve a recent result by L. Zhao.

Vasyl Ostrovskyi

For a star-shaped graph, we introduce special characters and study their properties. We decompose special characters into odd and even parts and study their evolution under reflections. We apply the obtained formulas to prove that the corresponding $*$-algebra have irreducible infinite-dimensional $*$-representations, if the graph contains an extended Dynkin

Eleni Tzanaki

Let $W$ be a Weyl group corresponding to the root system $A_{n-1}$ or $B_n$. We define a simplicial complex $ Δ^m_W $ in terms of polygon dissections for such a group and any positive integer $m$. For $ m=1 $, $ Δ^m_W$ is isomorphic to the cluster complex corresponding to $ W $, defined in \cite{FZ}. We enumerate the faces of $ Δ^m_W $ and show that the entr

Boris A. Springborn

It is known that for each combinatorial type of convex 3-dimensional polyhedra, there is a representative with edges tangent to the unit sphere. This representative is unique up to projective transformations that fix the unit sphere. We show that there is a unique representative (up to congruence) with edges tangent to the unit sphere such that the origin is

Stefano Bolognesi, Sven Bjarke Gudnason

We study the Abrikosov-Nielsen-Olesen multi-vortices. Using a numerical code we are able to solve the vortex equations with winding number up to n=25,000. We can thus check the wall vortex conjecture previously made in hep-th/0507273 and hep-th/0507286. The numerical results show a remarkable agreement with the theoretical predictions.

Simeon Hellerman

We present two new backgrounds of type IIA string theory preserving 16 supercharges. One is a Wilson line for (-1) to the left-moving spacetime fermion number, and the other is an orbifold by a reflection of four coordinates, along with the action of (-1) to the left-moving spacetime fermion number. The Wilson line theory has many new phenomena, including a

F. P. Zen, Arianto, B. E. Gunara, H. Zainuddin

The three 3-brane system with both positive or negative tension is studied in a low energy regime by using gradient expansion method. The effective equations of motion on the brane is derived and in particular we examine, in the first order, the radion effective lagrangian for this system. In this case, we show the solution of the modified Friedmann equation

Hiroshi Isono, Yutaka Matsuo

We generalize the idea of boundary states to open string channel. They describe the emission and absorption of the open string in the presence of intersecting D-branes. We study the algebra between such states under the star products of string field theory and confirm that they are projectors in a generalized sense. Based on this observation, we propose a mo

Jun-Chen Su

The quantization of the electroweak theory is performed starting from the Lagrangian given in the so-called unitary gauge in which the unphysical Goldstone fields disappear. In such a Lagrangian, the unphysical longitudinal components of the gauge fields and the residual gauge degrees of freedom are naturally eliminated by introducing the Lorentz gauge condi

Jurgen Berges, Szabolcs Borsanyi

Transport equations can be derived from quantum field theory assuming a loss of information about the details of the initial state and a gradient expansion. While the latter can be systematically improved, the assumption about a memory loss is in general not controlled by a small expansion parameter. We determine the range of validity of transport equations

Kyle S. Cranmer

The expected sensitivity of the LHC experiments to the discovery of the Higgs boson and the measurement of its properties is presented in the context of both the standard model and the its minimal supersymmetric extension. Prospects for a luminosity-upgraded ``Super-LHC&#39;&#39; are also presented.

M. T. Frandsen, C. Kouvaris, F. Sannino

We investigate the Corrigan-Ramond extension of one massless flavor Quantum Chromo Dynamics at nonzero quark chemical potential. Since the extension requires the fermions to transform in the two index antisymmetric representation of the gauge group, one finds that the number of possible channels is richer than in the &#39;t Hooft limit. We first discuss the

H. C. Eggers

Mathematical ideas and approaches common in complexity-related fields have been fruitfully applied in experimental high energy physics also. We briefly review some of the cross-pollination that is occurring.

Gunnar Ingelman

The idea of diffractive processes with a hard scale involved, to resolve the underlying parton dynamics, was published 1985 and experimentally verified 1988. Today hard diffraction is an active research field with high-quality data and new theoretical models. The trend from Regge-based pomeron models to QCD-based parton level models has given insights on QCD

Vincenzo Barone, Zhun Lu, Bo-Qiang Ma

We investigate the origin of the cos 2 phi azimuthal asymmetry in unpolarized semiinclusive DIS. The contributions to this asymmetry arising from the intrinsic transverse motion of quarks are explicitly evaluated, and predictions for the HERMES and COMPASS kinematic regimes are presented. We show that the effect of the leading-twist Boer-Mulders function h_1

Federico Mescia

Over the next years, the Flavour Physics community will be looking for inconsistencies of the Standard Model (SM) by exploiting new and precise measurements. In these ``indirect new physics&#39;&#39; searches, the key strategy is to concentrate on observables, which are theoretically clean and preferably suppressed in the SM. In this respect, the four golden

M. Ciuchini, E. Franco, D. Guadagnoli, V. Lubicz

We present the NLO corrections to the Wilson coefficients of the Delta F = 2 Hamiltonians in the strong interacting sector of the MSSM, responsible for neutral meson oscillations. Such corrections, combined with the NLO anomalous dimension matrix for the Delta F = 2 operators and the corresponding hadronic matrix elements calculated on the lattice, allow for

M. Anselmino

Some general remarks on parton transverse spin distributions and transverse motions are presented. The issue of accessing experimental information on the transversity distributions h_1^q is discussed. In particular direct information could be obtained from Drell-Yan processes with polarized protons and antiprotons (planned at GSI), while indirect information

L. B. Leinson, A. Perez

The process of $ν\barν$ radiation from a relativistic plasma of electrons and positrons is studied within the Random Phase Approximation.

D. Kekez, D. Klabucar, M. D. Scadron

Many meson processes are related to the U_A(1) axial anomaly, present in the Feynman graphs where fermion loops connect axial vertices with vector vertices. However, the coupling of pseudoscalar mesons to quarks does not have to be formulated via axial vertices. The pseudoscalar coupling is also possible, and this approach is especially natural on the level

H. Tsujimoto

It is found that the seesaw mechanism not only explain the smallness of neutrino masses but also account for the large mixing angles simultaneously, even if the unification of the neutrino Dirac mass matrix with that of up-type quark sector is realized. We show that provided the Majorana masses have hierarchical structure as is seen in the up-type quark sect

Michael Engelhardt

A random vortex world-surface model for the infrared sector of SU(4) Yang-Mills theory is constructed, focusing on the confinement properties and the behavior at the deconfinement phase transition. Although the corresponding data from lattice Yang-Mills theory can be reproduced, the model requires a more complex action and considerably more tuning than the S

N. Attig

The John von Neumann Institute for Computing (NIC) at the Research Centre Juelich, Germany, is one of the leading supercomputing centres in Europe. Founded as a national centre in the mid-eighties it now provides more and more resources to European scientists. This happens within EU-funded projects (I3HP, DEISA) or Europe-wide scientific collaborations. Beyo

Valeriya Gadiyak, Oleg Loktik

We present an unquenched lattice calculation for the SU(3) flavor breaking ratios of the heavy-light decay constants and the $ΔB = 2$ matrix elements. The calculation was performed on $16^3 \times 32$ lattices with two dynamical flavors of domain-wall quarks and inverse lattice spacing $1/a = 1.69(5)$ GeV. Heavy quarks were implemented using an improved latt

S. I. Serednyakov, M. N. Achasov, K. I. Beloborodov, A. G. Bogdanchikov

New results of the e+e- -> pi+pi-, K+K-, K_SK_L, pi0/gamma, eta0/gamma processes cross section measurements are presented. The results are based on the 30 pb^-1 data, accumulated by SND detector at VEPP-2M e+e- collider in the energy range sqrt(s)=0.4-1.4 GeV during 1995-2000 years. The comparison with existing experimental data shows that the measurement ac

Michele Arzano

Quantum-gravity corrections to the probability of emission of a particle from a black hole in the Parikh-Wilczek tunneling framework are studied. We consider the effects of zero-point quantum fluctuations of the metric on the emission probability for a tunneling shell. Quantum properties of the geometry are responsible for the formation of a &#34;quantum ego

Daniele Oriti

We construct a generalised formalism for group field theories, in which the domain of the field is extended to include additional proper time variables, as well as their conjugate mass variables. This formalism allows for different types of quantum gravity transition amplitudes in perturbative expansion, and we show how both causal spin foam models and the u

Jose Gaite

Spherical accretion flows are simple enough for analytical study, by solution of the corresponding fluid dynamic equations. The solutions of stationary spherical flow are due to Bondi. The questions of the choice of a physical solution and of stability have been widely discussed. The answer to these questions is very dependent on the problem of boundary cond

Aris L. Moustakas, Steven H. Simon, Thomas L. Marzetta

Differential Unitary Space-Time Modulation (DUSTM) and its earlier nondifferential counterpart, USTM, permit high-throughput MIMO communication entirely without the possession of channel state information (CSI) by either the transmitter or the receiver. For an isotropically random unitary input we obtain the exact closed-form expression for the probability d

Veljko Zlatic, R. Monnier, J. Freericks

The evolution of the thermopower EuCu{2}(Ge{1-x}Si{x}){2} intermetallics, which is induced by the Si-Ge substitution, is explained by the Kondo scattering of conduction electrons on the Eu ions which fluctuate between the magnetic 2+ and non-magnetic 3+ Hund&#39;s rule configurations. The Si-Ge substitution is equivalent to chemical pressure which modifies t

Francis W. Starr, Francesco Sciortino

We introduce and numerically study a model designed to mimic the bulk behavior of a system composed of single-stranded DNA dendrimers. Complementarity of the base sequences of different strands results in the formation of strong cooperative intermolecular links. We find that in an extremely narrow temperature range the system forms a large-scale, low-density

Justin Olamit, Zhi-Pan Li, Ivan K. Schuller, Kai Liu

Exchange anisotropy in ferromagnet/antiferromagnet (FM/AF) films is usually introduced along the cooling field or FM magnetization direction. Here we investigate the dependence of the exchange anisotropy, loop bifurcation, and reversal mechanism on the cooling field direction using vector magnetometry. Three types of samples (FM=Fe, Ni /AF = FeF2, MnF2) have

Augusto Gonzalez

In the present report, a set of theoretical results obtained in the period from 1991 to 2005 are reviewed. The physical systems under study include quark models of hadrons, inert atom clusters, atomic traps, and electrons and excitons confined in quantum dots. They contain three or more particles, and are described by nonrelativistic Quantum Mechanics. In th

Sergey Pankov

We propose a simple scaling ansatz for the full replica symmetry breaking solution of the Sherrington-Kirkpatrick model in the low energy sector. This solution is shown to become exact in the limit x->0, x>>T of the Parisi replica symmetry breaking scheme parameter x. The distribution function P(x,y) of the frozen fields y has been known to develop a linear

Jean-Francois Berret, Nicolas Schonbeck, Florence Gazeau, Delphine El Kharrat

When polyelectrolyte-neutral block copolymers are mixed in aqueous solutions with oppositely charged species, stable complexes are found to form spontaneously. The mechanism is based on electrostatics, and on the compensation between the opposite charges. Electrostatic complexes exhibit a core-shell microstructure. In the core, the polyelectrolyte blocks and

Jaeyoung Sung

Although the analysis in cond-mat/0510270 is correct, this doesn&#39;t mean Jarzynski relation holds always for an arbitrary process. There exists a sufficient and necessary condition for Jarzynski relation to hold for an adiabatic parameter switching process. In contradiction to recent assertions, the validity condition of Jarzynski relation for an adiabati

Pawel Bryk

We investigate effective interactions between a colloidal particle, immersed in a binary mixture of smaller spheres, and a semipermeable membrane. The colloid is modeled as a big hard sphere and the membrane is represented as an infinitely thin surface which is fully permeable to one of the smaller spheres and impermeable to the other one. Within the framewo

P. Nikunen, I. Vattulainen, M. Karttunen

Understanding the complex viscoelastic properties of polymeric liquids remains a challenge in materials science and soft matter physics. Here, we present a simple and computationally efficient criterion for the topological constraints in polymeric liquids using the Dissipative Particle Dynamics (DPD). The same approach is also applicable in other soft potent

V. Yu. Irkhin, M. I. Katsnelson

The role of the many-body (spin-polaronic) effects in the scanning tunneling spectroscopy of half-metallic ferromagnets (HMF) is considered. It is shown that the non-quasiparticle (NQP) states exist in the majority or minority spin gap in the presence of arbitrary external potential and, in particular, at the surfaces and interfaces. Energy dependence of the

Heon-Jung Kim, Hyun-Sook Lee, Byeongwon Kang, Woon-Ha Yim

We studied the temperature and the angular dependences of the upper critical field ($H_{c2}(T,θ$)) of Mg$_{1-x}$Al$_x$B$_2$ single crystals ($x = 0.12$ and 0.21) and compared with the dirty-limit two-gap theory. We found that $H_{c2}(T,θ)$&#39;s were well described in a unified way by this theory. The obtained values of the parameters indicated that as the A

Pinaki Sengupta, Leonid P. Pryadko

We combine model mapping, exact spectral bounds, and a quantum Monte Carlo method to study the ground state phases of a mixture of ultracold bosons and spin-polarized fermions in a one-dimensional optical lattice. The exact boundary of the boson-demixing transition is obtained from the Bethe Ansatz solution of the standard Hubbard model. We prove that along

P. Reichart, D. Spemann, A. Hauptner, A. Bergmaier

Recently, magnetic order in highly oriented pyrolytic graphite (HOPG) induced by proton broad- and microbeam irradiation was discovered. Theoretical models propose that hydrogen could play a major role in the magnetism mechanism. We analysed the hydrogen distribution of pristine as well as irradiated HOPG samples, which were implanted to micrometer-sized spo

Y. Nishi, P. A. Maksym, D. G. Austing, T. Hatano

We study the effects of electron-electron interactions in a circular few-electron vertical quantum dot in such a strong magnetic field that the filling factor $ν\le 1$. We measure excitation spectra and find ground state transitions beyond the maximum density droplet ($ν=1$) region. We compare the observed spectra with those calculated by exact diagonalizati

A. E. Allahverdyan, Zh. S. Gevorkian, Chin-Kun Hu, Th. M. Nieuwenhuizen

DNA adsorption and naturation is modeled via two interacting flexible homopolymers coupled to a solid surface. DNA denatures if the entropy gain for unbinding the two strands overcomes the loss of binding energy. When adsorbed to a surface, the entropy gain is smaller than in the bulk, leading to a stronger binding and, upon neglecting self-avoidance, absenc

Chun Xu, Dezhuan Han, Xin Wang, Xiaohan Liu

Doped semiconductors are intrinsically homogeneous media. However, by applying an external magnetic field that has a spatially periodic variation, doped semiconductors can behave extrinsically like conventional photonic crystals. We show this possibility theoretically by calculating the photonic band structures of a doped semiconductor under an external, spa

D. A. Sokolov, M. C. Aronson, W. Gannon, Z. Fisk

We present a study of the magnetic properties of Zr1-xNbxZn2, using an Arrott plot analysis of the magnetization. The Curie temperature TC is suppressed to zero temperature for Nb concentration xC=0.083+/-0.002, while the spontaneous moment vanishes linearly with TC as predicted by the Stoner theory. The initial susceptibility chi displays critical behavior

F. Lallet, R. Bachelet, A. Dauger, N. Olivi-Tran

We computed by a Monte Carlo method derived from the Solid on Solid model, the evolution of a polycrystalline thin film deposited on a substrate during thermal treatment. Two types of substrates have been studied: a single crystalline substrate with no defects and a single crystalline substrate with defects. We obtain islands which are either flat (i.e. with

A. V. Larionov, V. E. Bisti, M. Bayer, J. Hvam

The spin dynamics of an interwell excitons gas has been investigated in n-i-n GaAs/AlGaAs coupled quantum wells (CQWs). In these heterostructures the electron and the hole are spatially separated in neighboring quantum wells by a narrow AlAs barrier, when an electric field is applied. The time evolution kinetics of the interwell exciton photoluminescence has

Robert M. Ziff

Suggested by Scullard&#39;s recent star-triangle relation for bond correlated systems, we propose a general &#34;cell/dual-cell&#34; transformation, which allows in principle an infinite variety of lattices with exact percolation thresholds to be generated. We directly verify Scullard&#39;s new site percolation thresholds, and derive the bond thresholds for

Luca De Sanctis

We propose an ultrametric broken replica symmetry trial function for the diluted mean field sping glass model in the framework of random multi-overlap structure.

Jes K. Jorgensen, Doug Johnstone, Ewine F. van Dishoeck, Steven D. Doty

We discuss the effects of an enhanced interstellar radiation field (ISRF) on the observables of protostellar cores in the Orion cloud region. Dust radiative transfer is used to constrain the envelope physical structure by reproducing SCUBA 850 micron emission. Previously reported 13CO, C17O and H2CO line observations are reproduced through detailed Monte Car

B. C. Wilhite, D. E. Vanden Berk, R. J. Brunner, J. V. Brinkmann

We examine the variability of the high-ionizaton C IV line in a sample of 105 quasars observed at multiple epochs by the Sloan Digital Sky Survey. We find a strong correlation between the change in the C IV line flux and the change in the line width, but no correlations between the change in flux and changes in line center and skewness. The relation between

Stefan I. B. Cartledge, J. T. Lauroesch, David M. Meyer, Ulysses J. Sofia

We present interstellar elemental abundance measurements derived from Space Telescope Imaging Spectrograph echelle observations of 47 sight lines extending up to 6.5 kpc through the Galactic disk. These paths probe a variety of interstellar environments, covering ranges of nearly four orders of magnitude in molecular hydrogen fraction f(H_2) and more than tw

A. Rozanska, R. Goosmann, A. -M. Dumont, B. Czerny

We present a wide grid of models for the structure and transmission properties of warm absorbers in active galactic nuclei (AGN). Contrary to commonly used constant density models, our absorbing cloud is assumed to be under constant total (gas plus radiation) pressure. This assumption implies the coexistence of material at different temperatures and ionizati

G. S. Bisnovatyi-Kogan, O. Yu. Tsupko

The collapse of non-collisional dark matter and the formation of pancake structures in the Universe are investigated approximately. Collapse is described by a system of ordinary differential equations, in the model of a uniformly rotating, three-axis, uniform density ellipsoid. Violent relaxation, mass and angular momentum losses are taken into account pheno

Yutaka Fujita, Craig L. Sarazin, Gregory R. Sivakoff

We present an analysis of Chandra observations of the galaxy clusters A2670 and A2107. Their cD galaxies have large peculiar velocities (>200km/s) and thus the clusters appear to be undergoing mergers. In A2670, we find a comet-like structure around one of the brightest galaxies. At the leading edge of the structure, there is a cold front. The mass of the X-

Fabio D. Barazza, Shardha Jogee, Hans-Walter Rix, Marco Barden

We study the colors, structural properties, and star formation histories of a sample of ~1600 dwarfs over look-back times of ~3 Gyr (z=0.002-0.25). The sample consists of 401 distant dwarfs drawn from the Galaxy Evolution from Morphologies and SEDs (GEMS) survey, which provides high resolution Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) im

A. Palau, P. T. P. Ho, Q. Zhang, R. Estalella

We observed the HH 211 jet in the submillimeter continuum and the CO(3-2) and SiO(8-7) transitions with the Submillimeter Array. The continuum source detected at the center of the outflow shows an elongated morphology, perpendicular to the direction of the outflow axis. The high-velocity emission of both molecules shows a knotty and highly collimated structu

Olga K. Sil&#39;chenko

We have obtained 2D spectral data for a sample of 58 nearby S0 galaxies with the Multi-Pupil Spectrograph of the 6m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. The Lick indices H-beta, Mgb, and <Fe> are calculated separately for the nuclei and for the bulges taken as the rings between R=4&#34; and 7&#34;; and the lu

K. Ganda, J. Falcón-Barroso, R. F. Peletier, M. Cappellari

We present the stellar and gas kinematics of a sample of 18 nearby late-type spiral galaxies (Hubble types ranging from Sb to Sd), observed with the integral-field spectrograph SAURON at the 4.2-m William Herschel Telescope. SAURON covers the spectral range 4800-5380 A, allowing us to measure the Hbeta, Fe, Mgb absorption features and the emission in the Hbe

Yu. N. Efremov

Most star complexes are in fact complexes of stars, clusters and gas clouds; term &#34;star complexes&#34; was introduced as general one disregarding the preferential content of a complex. Generally the high rate of star formation in a complex is accompanied by the high number of bound clusters, including massive ones, what was explained by the high gas pres

L. Iapichino, M. Brüggen, W. Hillebrandt, J. C. Niemeyer

In the framework of the Chandrasekhar-mass deflagration model for Type Ia supernovae (SNe Ia), a persisting free parameter is the initial morphology of the flame front, which is linked to the ignition process in the progenitor white dwarf. Previous analytical models indicate that the thermal runaway is driven by temperature perturbations (&#39;&#39;bubbles&#

In Hee Park, Valentine Wakelam, Eric Herbst

We report a detailed attempt to model the ortho-to-para abundance ratio of c-C3H2 so as to reproduce observed values in the cores of the well-known source TMC-1. According to observations, the ortho-to-para ratios vary, within large uncertainties, from a low of near unity to a high of approximately three depending on the core. We used the osu.2003 network of

Mark Gieles, Soeren Larsen, Remco Scheepmaker, Nate Bastian

We present the luminosity function (LF) of star clusters in M51 based on HST/ACS observations taken as part of the Hubble Heritage project. The clusters are selected based on their size and with the resulting 5990 clusters we present one of the largest cluster samples of a single galaxy. We find that the LF can be approximated with a double power-law distrib

M. I. Arifyanto, B. Fuchs

We analysed the fine structure of the phase space distribution function of nearby subdwarfs using data extracted from various catalogues. Applying a new search strategy based on Dekker&#39;s theory of galactic orbits, we found four overdensely populated regions in phase space. Three of them were correlated with previously known star streams: the Hyades-Pleia

P. A. James, M. Salaris, J. I. Davies, S. Phillipps

(abridged) We introduce and discuss the properties of a theoretical (B-K)-(J-K) integrated colour diagram for single-age, single-metallicity stellar populations. This combination of integrated colours is able to largely disentangle the well known age-metallicity degeneracy when the age of the population is greater than ~300 Myr. We discuss in detail the effe

C. R. Cowley, G. M. Wahlgren

We report abundance excesses of 1.2 and 2.6 dex, respectively, for vanadium and bromine in the hot, peculiar star 3 Cen A. Abundances for these two odd-Z elements have not been previously reported for this star. Taken with previous work, they strengthen the case of the origin of the abundance peculiarities by diffusion.

A. E. García Pérez, F. Primas

A sample of metal-poor subgiants has been observed with the UVES spectrograph at the Very Large Telescope and abundances of Li and Be have been determined. Typical signal-to-noise per spectral bin values for the co-added spectra are of the order of 500 for the Li I line (670.78 nm) and 100 for the Be II doublet lines (313.04 nm). The spectral analysis of the

Steve H. Lubow, Gennaro D&#39;Angelo

We analyze the gas accretion flow through a planet-produced gap in a protoplanetary disk. We adopt the alpha disk model and ignore effects of planetary migration. We develop a semi-analytic, one-dimensional model that accounts for the effects of the planet as a mass sink and also carry out two-dimensional hydrodynamical simulations of a planet embedded in a

A. E. García Pérez, M. Asplund, F. Primas, P. E. Nissen

The debate on the oxygen abundances of metal-poor stars has its origin in contradictory results obtained using different abundance indicators. To achieve a better understanding of the problem we have acquired high quality spectra with the Ultraviolet and Visual Echelle Spectrograph at VLT, with a signal-to-noise of the order of 100 in the near ultraviolet an

V. Ripepi, S. Bernabei, M. Marconi, F. Palla

We present the results of a photometric multisite campaign on the $δ$ Scuti Pre-Main-Sequence star IP Per. Nine telescopes have been involved in the observations, with a total of about 190 hours of observations over 38 nights. Present data confirms the multiperiodic nature of this star and leads to the identification of at least nine pulsational frequencies.

Jean-Pierre Macquart, Geoff Bower

We determine the characteristics of the 7mm to 20cm wavelength radio variability in Sgr A* on time scales from days to three decades. The amplitude of the intensity modulation is between 30 and 39% at all wavelengths. Analysis of uniformly sampled data with proper accounting of the sampling errors associated with the lightcurves shows that Sgr A* exhibits no

S. A. Levshakov, M. Centurion, P. Molaro, S. D&#39;Odorico

Verification of theoretical predictions of an oscillating behavior of the fine-structure constant, alpha, with cosmic time requires high precision measurements at individual redshifts, while in earlier studies the mean Delta alpha/alpha values averaged over wide redshift intervals were usually reported. This requirement can be met via the Single Ion Differen

E. Carretti, S. Poppi, W. Reich, P. Reich

Polarized diffuse emission observations at 1.4-GHz in a high Galactic latitude area of the northern Celestial hemisphere are presented. The 3.2 X 3.2 deg^2 field, centred at RA = 10h 58m, Dec = +42deg 18&#39; (B1950), has Galactic coordinates l~172deg, b~+63deg and is located in the region selected as northern target of the BaR-SPOrt experiment. Observations

P. Reig, S. Martinez-Nunez, V. Reglero

We have used INTEGRAL & RXTE data to investigate the timing properties of the source in correlation with its spectral states as defined by different positions in the colour-colour diagram. The source shows two distinct branches in the colour-colour diagram that resemble those of the Z sources. The hard branch (similar to the horizontal branch of Z sources) i