December 2005 arXiv papers — page 12

Stefan Forste, Hans Peter Nilles, Akin Wingerter

We study spontaneous gauge symmetry breaking in the framework of orbifold compactifcations of heterotic string theory. In particular we investigate the electroweak symmetry breakdown via the Higgs mechanism. Such a breakdown can be achieved by continuous Wilson lines. Exploiting the geometrical properties of this scheme we develop a new technique which simpl

P. Diaz, M. A. Per, A. Segui

The most entropic fluid can be related to a dense gas of black holes that we use to study the beginning of the universe. We encounter difficulties to compatibilize an adiabatic expansion with the growing area for the coalescence of black holes. This problem may be circumvented for a quantum black hole fluid, whose classical counterpart can be described by a

L. P. Colatto, A. L. A. Penna, W. C. Santos

In this paper we study the nonlocal effects of noncommutative spacetime on simple physical systems. Our main point is the assumption that the noncommutative effects are consequences of a background field which generates a local spin structure. So, we reformulate some simple electrostatic models in the presence of a spin-deformation contribution to the geomet

G. Takacs, F. Wagner

We reconsider the mass spectrum of double sine-Gordon theory where recent semiclassical results called into question the previously accepted picture. We use the Truncated Conformal Space Approach (TCSA) to investigate the claims. We demonstrate that the numerics supports the original results, and strongly disagrees with those obtained from semiclassical soli

B. Pioline, A. Waldron

Motivated by issues in string theory and M-theory, we provide a pedestrian introduction to automorphic forms and theta series, emphasizing examples rather than generality.

Jan Kalinowski

Reconstruction of the fundamental supersymmetric theory and its breaking mechanism will require high-precision tools. Here a brief introduction to SPA, the Supersymmetry Parameter Analysis (SPA) Convention and Project, is presented which is based on a consistent set of conventions and input parameters.

B. Borasoy, R. Nissler, W. Weise

It has recently been claimed by Oller et al. [PRL 95 (2005) 172502] that the DEAR kaonic hydrogen data can be reconciled with K^- p scattering data in a chiral unitary approach. In this comment we demonstrate that the proposed solution violates fundamental principles of scattering theory.

V. Guzey

Using the approximate flavor SU(3) symmetry of strong interactions, we argue for the existence of a new Lambda baryon with J^P=3/2^-, the mass around 1850 MeV, the total width of about 130 MeV, significant branching into the Sigma πand Sigma^{\ast} πstates and a vanishingly small coupling to the N {\bar K} state. This confirms quark model predictions suggest

Andreas Gerhold, Andreas Ipp, Anton Rebhan

We review the existing weak-coupling results on the thermodynamic potential of deconfined QCD at small and large quark chemical potential and compare with results from lattice gauge theory as well as the exactly solvable case of large-N_f QCD. We also discuss the new analytical results on non-Fermi-liquid effects in entropy and specific heat as well as in di

F. J. Botella

We analyse the present experimental evidence for a complex CKM matrix, even allowing for New Physics contributions to $ε_{K}$, $a_{J/ΨK_{S}}$%, $ΔM_{B_{d}}$, $ΔM_{B_{s}}$, and the $ΔI=1/2$ piece of $% B\to ρρ$ and $B\to ρπ$. We emphasize the crucial rôle played by the angle $γ$ in both providing irrefutable evidence for a 3$\times $3 complex CKM matrix and p

Robert Fleischer

In this decade, the exploration of CP violation is governed by the B-meson system, where non-leptonic decays play an outstanding role. To set the stage, we have first a look at the main strategies to circumvent the calculation of the relevant hadronic matrix elements in these studies, and discuss popular avenues for physics beyond the Standard Model to enter

I. I. Bigi, B. Blossier, A. Le Yaouanc, L. Oliver

After the successes the OPE description has scored in describing $\bar B \to l \bar νX_c$ decays, we need to study what can be said about the composition of the hadronic final state $X_c$. The same OPE treatment yields sum rules implying the dominance of $j_q = 3/2$ charm states in $X_c$ over their $j_q=1/2$ counterparts. This prediction is supported by othe

M. Wakamatsu

It is shown that, based only upon two empirically known facts besides two reasonable theoretical postulates, we are inevitably led to a model-independent conclusion that the quark orbital angular momentum carries nearly half of the total nucleon spin at the low energy scale of nonperturbative QCD. Also shown are explicit model predictions for the forward lim

A. Feo

The lattice Wess-Zumino model written in terms of the Ginsparg-Wilson relation is invariant under a generalized supersymmetry transformation which is determined by an iterative procedure in the coupling constant. By studying the associated Ward-Takahashi identity up to order $g^2$ we show that this lattice supersymmetry automatically leads to restoration of

Martin Gürtler, Thomas Streuer, Gerrit Schierholz, David Galletly

We compute light and strange quark masses for quenched overlap fermions at two values of the gauge coupling. The renormalisation is done non-perturbatively. We test the predictions of quenched chiral perturbation theory for the quark mass dependence of the hadron spectrum and see evidence for the existence of chiral logs.

M. Procura, B. U. Musch, T. R. Hemmert, W. Weise

We present an updated analysis of the quark mass dependence of the nucleon mass and nucleon axial-vector coupling g_A, comparing different formulations of SU(2) Baryon Chiral Effective Field Theory, with and without explicit delta (1232) degrees of freedom. We discuss the outcome of the corresponding interpolations between lattice QCD data and the physical v

CDF Collaboration

Results on a search for pair production of second generation scalar leptoquark in $p \bar{p}$ collisions at $\sqrt{s}$=1.96 TeV are reported. The data analyzed were collected by the CDF detector during the 2002-2003 Tevatron Run II and correspond to an integrated luminosity of 198 pb$^{-1}$. Leptoquarks (LQ) are sought through their decay into (charged) lept

Gabriella Pasztor

Data collected by the OPAL detector at LEP up to the highest energies of 209 GeV are analyzed to search for evidence of supersymmetric (SUSY) particle production. Chargino pair-production and neutralino associated production are considered in models where supersymmetry breaking is mediated by gravitational interactions. The focus of the searches is on topolo

M. Sumihama

Differential cross sections and photon beam asymmetries for the gamma p rightarrow K+ Lambda and gamma p rightarrow K+ Sigma0 reactions have been measured in the photon energy range from 1.5 GeV to 2.4 GeV and in the angular range from Theta_{cm} = 0 to 60 of the K+ scattering angle in the center of mass system at the SPring-8/LEPS facility. The photon beam

M. Gaudin, V. Gorini, A. Kamenshchik, U. Moschella

We study a set of static solutions of the Einstein equations in presence of a massless scalar field and establish their connection to the Kantowski-Sachs cosmological solutions based on some kind of duality transformations. The physical properties of the limiting case of an empty hyperbolic spacetime (pseudo-Schwarzschild geometry) are analyzed in some detai

Soma Nath, Subenoy Chakraborty, Ujjal Debnath

Gravitational collapse of FRW brane world embedded in a conformaly flat bulk is considered for matter cloud consists of dark matter and dark energy with equation of state $p=ερ$ $(ε<-{1/3})$. The effect of dark matter and dark energy is being considered first separately and then a combination of them both with and without interaction. In some cases the colla

Mihalis Dafermos, Igor Rodnianski

We consider solutions to the linear wave equation on a (maximally extended) Schwarzschild spacetime, assuming only that the solution decays suitably at spatial infinity on a complete Cauchy hypersurface. (In particular, we allow the support of the solution to contain the bifurcate event horizon.) We prove uniform decay bounds for the solution in the exterior

Ayse H. Bilge, Durmus Daghan

Einstein&#39;s field equations for a spherically symmetric metric coupled to a massless scalar field are reduced to a system effectively of second order in time, in terms of the variables $μ=m/r$ and $y=(α/ra)$, where $a$, $α$, $r$ and $m$ are as in [W.M. Choptuik, ``Universality and Scaling in Gravitational Collapse of Massless Scalar Field&#34;, \textit{Ph

Todd Holloway, Miran Bozicevic, Katy Börner

This paper presents a novel analysis and visualization of English Wikipedia data. Our specific interest is the analysis of basic statistics, the identification of the semantic structure and age of the categories in this free online encyclopedia, and the content coverage of its highly productive authors. The paper starts with an introduction of Wikipedia and

Nikita Sakhanenko, Hanna Makaruk

Metal melting on release after explosion is a physical system far from quilibrium. A complete physical model of this system does not exist, because many interrelated effects have to be considered. General methodology needs to be developed so as to describe and understand physical phenomena involved. The high noise of the data, moving blur of images, the high

Hector Ruiz Barradas, Didier Bert

We present a fixpoint semantics of event systems. The semantics is presented in a general framework without concerns of fairness. Soundness and completeness of rules for deriving &#34;leads-to&#34; properties are proved in this general framework. The general framework is instantiated to minimal progress and weak fairness assumptions and similar results are o

Atif Imtiaz, Steven M. Anlage

The Near-Field Scanning Microwave Microscope (NSMM) can quantitatively image materials properties at length scales far shorter than the free space wavelength (λ). Here we report a study of the effect of tip-geometry on the NSMM signals. This particular NSMM utilizes scanning tunneling microscopy (STM) for distance-following control. We systematically examine

J. W. Clark, A. Mandilara, M. L. Ristig

Entanglement properties of the trial many-body wave functions in variational treatments of the transverse Ising model in two, three, and four dimensions are investigated. Based on data for magnetizations and correlation functions generated by for symmetry-breaking Hartree-Jastrow trial ground states, results are presented for several measures of bipartite en

Pedro G. Lind, Ana Nunes, Jason A. C. Gallas

We investigate the impact of bistability in the emergence of synchronization in networks of chaotic maps with delayed coupling. The existence of a single finite attractor of the uncoupled map is found to be responsible for the emergence of synchronization. No synchronization is observed when the local dynamics has two competing chaotic attractors whose orbit

Martin Albrecht, Bo Song, Alexander Schnurpfeil

We present a novel ab initio non-equilibrium approach to calculate the current across a molecular junction. The method rests on a wave function based description of the central region of the junction combined with a tight binding approximation for the electrodes in the frame of the Keldysh Green&#39;s function formalism. In addition we present an extension s

R. Gommers, S. Bergamini, F. Renzoni

We analyze the atomic dynamics in an ac driven periodic optical potential which is symmetric in both time and space. We experimentally demonstrate that in the presence of dissipation the symmetry is broken, and a current of atoms through the optical lattice is generated as a result.

R. Gommers, P. Douglas, S. Bergamini, M. Goonasekera

We demonstrate the phenomenon of resonant activation in a non-adiabatically driven dissipative optical lattice with broken time-symmetry. The resonant activation results in a resonance as function of the driving frequency in the current of atoms through the periodic potential. We demonstrate that the resonance is produced by the interplay between determinist

P. H. Jones, M. Goonasekera, F. Renzoni

We have realized a Brownian motor by using cold atoms in a dissipative optical lattice as a model system. In our experiment the optical potential is spatially symmetric and the time-symmetry of the system is broken by applying appropriate zero-mean ac forces. We identify a regime of rectification of forces and a regime of rectification of fluctuations, the l

F. Renzoni

Brownian motors are devices which &#34;rectify&#34; Brownian motion, i.e. they can generate a current of particles out of unbiased fluctuations. Brownian motors are important for the understanding of molecular motors, and are also promising for the realization of new nanolelectronic devices. Among the different systems that can be used to study Brownian moto

Karen E. Daniels, Robert P. Behringer

We describe experiments on monodisperse spherical particles in an annular cell geometry, vibrated from below and sheared from above. This system shows a freezing/melting transition such that under sufficient vibration a crystallized state is observed, which can be melted by sufficient shear. We characterize the hysteretic transition between these two states,

Bryan K. Clark, D. M. Ceperley

Measurements of the moment of inertia by Kim and Chan have found that solid 4He acts like a supersolid at low temperatures. To understand the order in solid 4He, we have used Path Integral Monte Carlo to calculate the off-diagonal long range order (ODLRO) (equivalent to Bose-Einstein condensation, BEC). We do not find ODLRO in a perfect hcp crystal at the me

S. Bellucci, J. Gonzalez, P. Onorato, E. Perfetto

We develop in this paper a theoretical framework that applies to the intermediate regime between the Coulomb blockade and the Luttinger liquid behavior in multi-walled carbon nanotubes. Our main goal is to confront the experimental observations of transport properties, under conditions in which the thermal energy is comparable to the spacing between the sing

Jean-Michel Caillol, Oksana Patsahan, Ihor Mryglod

The collective variable representation (CV) of classical statistical systems such as simple liquids has been intensively developed by the Ukrainian school after seminal works by Prof. Ihor Yukhnovskii. The basis and the structure of the CV representation are reexamined here from the point of view of statistical field theory and compared with another exact st

R. Miller, E. -W. Scheidt, G. Eickerling, C. Helbig

Polymeric methyltrioxorhenium, {(CH_{3})_{0.92}ReO_{3}}_{\infty} (poly-MTO), is the first member of a new class of organometallic hybrids which adopts the structural pattern and physical properties of classical perovskites in two dimensions (2D). We demonstrate how the electronic structure of poly-MTO can be tailored by intercalation of organic donor molecul

S. Bellucci, P. Onorato

We investigate the ballistic electron transport in a two dimensional Quantum Wire under the action of an electric field ($E_y$). We demonstrate how the presence of a Spin Orbit coupling, due to the uniform electric confinement field gives a non-commutative effect as in the presence of a transverse magnetic field. We discuss how the non commutation implies an

Kausik Sengupta, E. V. Sampathkumaran

The compound, Nd7Rh3, crystallizing in Th7Fe3-type hexagonal structure, was previously known to exhibit two magnetic transitions, one at 32 K and the other at 10 K (in zero magnetic field). Here, we report the existence of a field-induced first-order antiferromagnetic to ferromagnetic transition at 1.8 K in this compound. On the basis of the measurements of

R. Krahne, G. Chilla, C. Schueller, L. Carbone

We investigated CdTe nanocrystal tetrapods of different sizes by resonant inelastic light scattering at room temperature and under cryogenic conditions. We observe a strongly resonant behavior of the phonon scattering with the excitonic structure of the tetrapods. Under resonant conditions we detect a set of phonon modes that can be understood as confined lo

Richard Bouzerar, Georges Bouzerar, Timothy Ziman

We calculate Curie temperatures and study the stability of ferromagnetism in diluted magnetic materials, taking as a model for the exchange between magnetic impurities a damped Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction and a shor t range term representing the effects of superexchange. To properly include effects of spin and thermal fluctuations as wel

Iacopo Carusotto

Bragg scattering with linearly polarized light can be used to separately measure the density and the spin structure factor of a two spin component atomic gas by looking at the dependance of the scattering intensity on the polarization of the laser fields. Both stimulated and spontaneous scattering are discussed. Explicit results for different spin configurat

G. Górski, J. Mizia

In this contribution we would like to revisit the problems of ferromagnetism (F) and antiferromagnetism (AF) in the pure itinerant model. These methods can be extended later to the superconducting materials. In our model we assume the extended Hubbard Hamiltonian. Transition from the paramagnetic state to the ordered state of magnetic nature is decided by th

V. Markovich, M. Auslender, I. Fita, R. Puzniak

Magnetic properties of polycrystalline CaMn1-xRuxO3 (x = 0 - 0.5) samples were investigated in the temperature range 4.2 - 250 K, under external magnetic field up to 15 kOe and under hydrostatic pressure up to 12 kbar. Transport properties of the samples with x = 0.1, 0.2, 0.4, 0.5 were also investigated under pressure up to 10 kbar. For x up to 0.4, the pre

G. Herranz, M. Basletic, M. Bibes, R. Ranchal

We report on the growth of heterostructures composed of layers of the high-Curie temperature ferromagnet Co-doped (La,Sr)TiO3 (Co-LSTO) with high-mobility SrTiO3 (STO) substrates processed at low oxygen pressure. While perpendicular spin-dependent transport measurements in STO//Co-LSTO/LAO/Co tunnel junctions demonstrate the existence of a large spin polariz

L. Seetha Lakshmi, K. Doerr, K. Nenkov, A. Handstein

In this paper, we discuss the most deleterious effect of charge state modification at the Mn site on the ground state of the CMR manganites.

Giorgio Parisi, Frantisek Slanina

We develop an effective field theory for lattice models, in which the only non-vanishing diagrams exactly reproduce the topology of the lattice. The Bethe-Peierls approximation appears naturally as the saddle point approximation. The corrections to the saddle-point result can be obtained systematically. We calculate the lowest loop corrections for magnetisat

L. Benfatto, M. Silva Neto, V. Juricic, C. Morais Smith

We derive the long-wavelength non-linear sigma model for a two-dimensional Heisenberg system in the presence of the Dzyaloshinskii-Moriya and pseudodipolar interactions. We show that the system is a non-conventional easy-axis antiferromagnet, displaying an anomalous coupling between the magnetic field and the staggered order parameter. Our results are in goo

H. S. Jeevan, Z. Hossain, C. Geibel

e have investigated the magnetic properties of YbRu$_{2}$Ge$_{2}$ by means of magnetic susceptibility $χ$(T), specific heat C(T) and electrical resistivity $ρ$(T) measurements performed on flux grown single crystals. The Curie-Weiss behavior of $χ$(T) along the easy plane, the large magnetic entropy at low temperatures and the weak Kondo like increase in $ρ$

Valmir C. Barbosa, Raul Donangelo, Sergio R. Souza

We introduce a new mechanism of connectivity evolution in networks to account for the emergence of scale-free behavior. The mechanism works on a fixed set of nodes and promotes growth from a minimally connected initial topology by the addition of edges. A new edge is added between two nodes depending on the trade-off between a gain and a cost function of loc

B. A. Piot, D. K. Maude, M. Henini, Z. R. Wasilewski

Spin splitting in the integer quantum Hall effect is investigated for a series of Al$_{x}$Ga$_{1-x}$As/GaAs heterojunctions and quantum wells. Magnetoresistance measurements are performed at mK temperature to characterize the electronic density of states and estimate the strength of many body interactions. A simple model with no free parameters correctly pre

H. Yoshida, Y. Muraoka, T. Soergel, M. Jansen

A novel metallic and magnetic transition metal oxide Ag2NiO2 is studied by means of resistivity, magnetic susceptibility, specific heat and X-ray diffraction. The crystal structure is characterized by alternating stacking of a Ni3+O2 layer and a (Ag2)+ layer, the former realizing a spin-1/2 triangular lattice with eg orbital degeneracy and the latter providi

G. T. Liu, J. L. Luo, Y. Q. Guo, S. K. Su

A series of in-plane substituted compounds, including Cu-site (SrZn$_x$Cu$_{2-x}$(BO$_3$)$_2$), and B-site (SrCu$_2$(Si$_x$B$_{1-x}$O$_3$)$_2$) substitution, were synthesized by solid state reaction. X-ray diffraction measurements reveal that these compounds are single-phase materials and their in-plane lattice parameter depends systematically on the substit

S. Wildermuth, S. Hofferberth, I. Lesanovsky, S. Groth

We discuss the application of Bose-Einstein condensates (BECs) as sensors for magnetic and electric fields. In an experimental demonstration we have brought one-dimensional BECs close to micro-fabricated wires on an atom chip and thereby reached a sensitivity to potential variations of ~10e-14eV at 3 micron spatial resolution. We demonstrate the versatility

Didier Poilblanc, Andreas Laeuchli, Matthieu Mambrini, Frederic Mila

The confinement of a spinon liberated by doping two-dimensional frustrated quantum antiferromagnets with a non-magnetic impurity or a mobile hole is investigated. For a static vacancy, an intermediate behavior between complete deconfinement (kagome) and strong confinement (checkerboard) is identified in the J_1{-}J_2{-}J_3 model on the square lattice, with t

M. Governale, F. Taddei, F. W. J. Hekking, Rosario Fazio

We present a formalism to study adiabatic pumping through a superconductor - normal - superconductor weak link. At zero temperature, the pumped charge is related to the Berry phase accumulated, in a pumping cycle, by the Andreev bound states. We analyze in detail the case when the normal region is short compared to the superconducting coherence length. The p

Lars Fritz, Matthias Vojta

The Kondo effect in superconductors is frequently investigated using the local quasiparticle density of states as sole bath characteristics, i.e., the presence of anomalous propagators is ignored. Here we point out that this treatment is exact for a number of situations, including point-like impurities in d-wave superconductors. We comment on recent investig

W. Yi, L. -M. Duan

This paper has been withdrawn by the authors as the recent measurement of the closed channel population for Li6 [Partridge et al., cond-mat/0505353] indicates that the cutoff energy is still much larger than any other relevant energy scales for this broad Feshbach resonance.

Man Hoi Lee, R. Paul Butler, Debra A. Fischer, Geoffrey W. Marcy

We present an analysis of the HD 82943 planetary system based on a radial velocity data set that combines new measurements obtained with the Keck telescope and the CORALIE measurements published in graphical form. We examine simultaneously the goodness of fit and the dynamical properties of the best-fit double-Keplerian model as a function of the poorly cons

S. F. Sanchez, N. Cardiel, M. Verheijen, N. Benitez

We report on integral field spectrocopy observations, performed with the PPAK module of the PMAS spectrograph, covering a field-of-view of ~74&#39;&#39;X64&#39;&#39; centered on the core of the galaxy cluster Abell 2218. A total of 43 objects were detected, 27 of them galaxies at the redshift of the cluster. We deblended and extracted the integrated spectra

J. R. Peterson, A. C. Fabian

We review the X-ray spectra of the cores of clusters of galaxies. Recent high resolution X-ray spectroscopic observations have demonstrated a severe deficit of emission at the lowest X-ray temperatures as compared to that expected from simple radiative cooling models. The same observations have provided compelling evidence that the gas in the cores is coolin

N. P. Abel, G. J. Ferland, C. R. O&#39;Dell, G. Shaw

Orion&#39;s Veil is an absorbing screen that lies along the line of sight to the Orion H II region. It consists of two or more layers of gas that must lie within a few parsecs of the Trapezium cluster. Our previous work considered the Veil as a whole and found that the magnetic field dominates the energetics of the gas in at least one component. Here we use

Tom Richtler

I comment (in a review fashion) on a few selected topics in the field of extragalactic globular clusters with strong emphasis on recent work. The topics are: bimodality in the colour distribution of cluster systems, young massive clusters, and the brightest old clusters. Globular cluster research, perhaps more than ever, has lead to important (at least to as

Jean-Baptiste Le Bouquin, Pierre Labeye, Fabien Malbet, Laurent Jocou

Our objective is to prove that integrated optics (IO) is not only a good concept for astronomical interferometry but also a working technique with high performance. We used the commissioning data obtained with the dedicated K-band integrated optics two-telescope beam combiner which now replaces the fiber coupler MONA in the VLTI/VINCI instrument. We characte

Anna Frebel, Norbert Christlieb, John E. Norris, Wako Aoki

From a newly obtained VLT/UVES spectrum we have determined the oxygen abundance of HE 1327-2326, the most iron-poor star known to date. UV-OH lines yield a 1D LTE abundance of [O/Fe]_OH = 3.7 (subgiant case) and [O/Fe]_OH = 3.4 (dwarf case). Using a correction of -1.0 dex to account for 3D effects on OH line formation, the abundances are lowered to [O/Fe] =

J. C. O&#39;Linger, D. M. Cole, M. E. Ressler, G. A. Wolf-Chase

We present ground-based mid-infrared observations of Class 0 protostars in LDN 1448. Of the five known protostars in this cloud, we detected two, L1448N:A and L1448C, at 12.5, 17.9, 20.8, and 24.5 microns, and a third, L1448 IRS 2, at 24.5 microns. We present high-resolution images of the detected sources, and photometry or upper limits for all five Class 0

Rodrigo S. Nemmen, Thaisa Storchi-Bergmann, Feng Yuan, Michael Eracleous

We present a model for the accretion flow around the supermassive black hole in the LINER nucleus of NGC 1097 which fits the optical to X-ray spectral energy distribution (SED). The X-ray segment of the SED is based on observations with the Chandra X-Ray Observatory, which are reported here for the first time. The inner part of the flow is modeled as a radia

C. Moni Bidin, R. A. Mendez, S. Moehler, G. Piotto

We performed a spectroscopic search for binaries among hot Horizontal Branch stars in globular clusters. We present final results for a sample of 51 stars in NGC6752, and preliminary results for the first 15 stars analyzed in M80. The observed stars are distributed along all the HBs in the range 8000 < Teff < 32000 K, and have been observed during four night

R. B. Barreiro

The detection of compact sources embedded in a background is a very common problem in many fields of Astronomy. In these lecture notes we present a review of different techniques developed for the detection and extraction of compact sources, with a especial focus on their application to the field of the cosmic microwave background radiation. In particular, w

G. Risaliti, E. Sani, R. Maiolino, A. Marconi

We present 3-5 micron spectroscopy of the interacting system NGC 6240, showing the presence of two active galactic nuclei. The brightest (southern) nucleus shows up with a starburst-like emission, with a prominent 3.3 micron emission feature. However, the presence of an AGN is revealed by the detection of a broad Br alpha emission line, with a width of ~1,80

C. Meurer, J. Bluemer, R. Engel, A. Haungs

In this work, the relation between muon production in extensive air showers and features of hadronic multiparticle production at low energies is studied. Using CORSIKA, we determine typical energies and phase space regions of secondary particles which are important for muon production in extensive air showers and confront the results with existing fixed targ

Deborah Baines, Rene Oudmaijer, John Porter, Monica Pozzo

We present high resolution spectro-astrometry of a sample of 28 Herbig Ae/Be and 3 F-type pre-main sequence stars. The spectro-astrometry is shown from both empirical and simulated data to be capable of detecting binary companions that are fainter by up to 6 magnitudes at separations larger than 0.1 arcsec. The nine targets that were previously known to be a

P. Lazorenko, Yu. Babenko, V. Karbovsky, M. Buromsky

A catalogue of astrometric (positions, proper motions) and photometric (B, V, R, r&#39;, J) data of stars in fields with ICRF objects has been compiled at the Observatory of the National Academy of Sciences of Ukraine and the Kyiv University Observatory. All fields are located in the declination zone from 0 to +30 degrees; the nominal field size is 46&#39; (

C. L. Fryer, G. Rockefeller, M. S. Warren

We provide a description of the SNSPH code--a parallel 3-dimensional radiation hydrodynamics code implementing treecode gravity, smooth particle hydrodynamics, and flux-limited diffusion transport schemes. We provide descriptions of the physics and parallelization techniques for this code. We present performance results on a suite of code tests (both standar

D. de Martino, J. -M. Bonnet-Bidaud, M. Mouchet, B. T. Gaensicke

We present the first time resolved medium resolution optical spectroscopy of the recently identified peculiar Intermediate Polar (IP) 1RXSJ154814.5-452845, which allows us to precisely determine the binary orbital period (Porb=9.87+/-0.03hr) and the white dwarf spin period Pspin=693.01+/-0.06s). This system is then the third just outside the purported 6-10hr

U. Geppert, M. Kueker, Dany Page

We continue the study of the effects of a strong magnetic field on the temperature distribution in the crust of a magnetized neutron star (NS) and its impact on the observable surface temperature. Extending the approach initiated in Geppert et al.(2004), we consider more complex and, hence, more realistic, magnetic field structures but still restrict ourselv

Linqing Wen, Alan M. Levine, Robin H. D. Corbet, Hale V. Bradt

We present the results of a systematic search in 8.5 years of Rossi X-ray Timing Explorer All-Sky Monitor data for evidence of periodicities. The search was conducted by application of the Lomb-Scargle periodogram to the light curves of each of 458 actually or potentially detected sources in each of four energy bands (1.5-3 keV, 3-5 keV, 5-12 keV, and 1.5-12

E. Meyer-Hofmeister, F. Meyer

Heat conduction plays an important role in the balance between heating and cooling in many astrophysical objects, e.g. cooling flows in clusters of galaxies. Here we investigate the effect of heat conduction on the interaction between a cool disk and a hot corona around black holes. Using the one-radial-zone approximation, we study the vertical structure of

M. A. Moscibrodzka

We consider the sample of weakly active galaxies situated in &#39;Local Universe&#39; collected in the paper of Pellegrini (2005) with inferred accretion efficiencies from $10^{-2}$ to $10^{-7}$. We apply a model of spherically symmetrical Bondi accretion for given parameters ($M_{BH}$,$T_{\infty}$,$ρ_{\infty}$,) taken from observation. We calculate spectra

Tianmeng Zhang, Xiaofeng Wang, Weidong Li, Xu Zhou

We present photometric data of the type II-P supernova (SN) 2004dj in NGC 2403. The multicolor light curves cover the SN from $\sim$ 60 to 200 days after explosion, and are measured with a set of intermediate-band filters that have the advantage of tracing the strength variations of some spectral features. The light curves show a flat evolution in the middle

B. Neichel, T. Fusco, M. Puech, J-M. Conan

In this paper, we present a first comparison of different Adaptive Optics (AO) concepts to reach a given scientific specification for 3D spectroscopy on Extremely Large Telescope (ELT). We consider that a range of 30%-50% of Ensquarred Energy (EE) in H band (1.65um) and in an aperture size from 25 to 100mas is representative of the scientific requirements. F

Petro F. Lazorenko, Galina A. Lazorenko

This paper presents a non-classic approach to narrow field astrometry that offers a significant improvement over conventional techniques due to enhanced reduction of atmospheric image motion. The method is based on two key elements: apodization of the entrance pupil and the enhanced virtual symmetry of reference stars. Symmetrization is implemented by settin

G. Rowell, F. Aharonian, A. Plyasheshnikov

The origin of Galactic CRs up the knee energy remains unanswered and provides strong motivation for the study of gamma-ray sources at energies above 10 TeV. We discuss recent results from ground-based gamma-ray Cherenkov imaging systems at these energies as well as future observational efforts in this direction. The exciting results of H.E.S.S. give clues as

C. S. Stalin, Gopal-Krishna, Ram Sagar, Paul J. Wiita

We report results of multiband optical monitoring of two well known blazars, S5 0716+714 and BL Lacertae, carried out in 1996 and 2000-01 with an aim to study optical variations on time scales from minutes to hours and longer.The light curves were derived relative to comparison stars present on the CCD frames. Night to night flux variations of >0.1 mag were

Harinder P. Singh, Manabu Yuasa, Nawo Yamamoto, Ranjan Gupta

The Indo-US coudé feed stellar spectral library (CFLIB) made available to the astronomical community recently by Valdes et al. (2004) contains spectra of 1273 stars in the spectral region 3460 to 9464 Åat a high resolution of 1 ÅFWHM and a wide range of spectral types. Cross-checking the reliability of this database is an important and desirable exercise sin

Hiroyuki Nakanishi, Yoshiaki Sofue, Jin Koda

We present high-resolution ($1\farcs8$ -- $4\farcs5$) CO data of the Virgo spiral galaxy NGC 4569, obtained using the Nobeyama Millimeter Array. We found that the molecular gas is highly concentrated in the circumnuclear region with two off-center peaks. A CO image with the highest angular resolution of $2\farcs0 \times 1\farcs8$ shows that six blobs likely

Renxin Xu

Members of the family of pulsar-like stars are distinguished by their different manifestations observed, i.e., radio pulsars, accretion-driven X-ray pulsars, X-ray bursts, anomalous X-ray pulsars/soft gamma-ray repeaters, compact center objects, and dim thermal neutron stars. Though one may conventionally think that these stars are normal neutron stars, it i

Osamu Iguchi, Yasuhide Sota, Akika Nakamichi, Masahiro Morikawa

We demonstrate that the quasi-equilibrium state in self-gravitating $N$-body system after cold collapse are uniquely characterized by the local virial relation using numerical simulations. Conversely assuming the constant local virial ratio and Jeans equation for spherically steady state system, we investigate the full solution space of the problem under the

Matthieu Gounelle, Frank H. Shu, Hsien Shang, A. E. Glassgold

Two explanations exist for the short-lived radionuclides present in the solar system when the CAIs first formed. They originated either from the ejecta of a supernova or by the in situ irradiation of nebular dust by energetic particles. With a half-life of only 53 days, Beryllium-7 is then the key discriminant, since it can be made only by irradiation. We ca

Max Tegmark, Nick Bostrom

Numerous Earth-destroying doomsday scenarios have recently been analyzed, including breakdown of a metastable vacuum state and planetary destruction triggered by a &#34;strangelet&#39;&#39; or microscopic black hole. We point out that many previous bounds on their frequency give a false sense of security: one cannot infer that such events are rare from the t

K. Zioutas, Y. Semertzidis, Th. Papaevangelou

The origin of various celestial phenomena have remained mysterious for conventional astrophysics. Therefore, alternative solutions should be considered, taking into account the involvement of unstable dark-matter particle candidates, such as the celebrated axions or other as yet unforeseen axion-like particles. Their spontaneous and induced decay by the ubiq

B. P. Gong

There are four puzzles on 1E 1207.4-5209: (1) the characteristic age of the pulsar is much higher than the estimated age of the supernova remnant; (2) the magnetic field inferred from spin-down is significantly different from the value obtained from the cyclotron absorption lines; (3) the spinning down of the pulsar is non-monotonic; (4) the magnitude of the

CDF Collaboration, A. Abulencia

We present a search for Higgs bosons decaying into b-bbar and produced in association with W bosons in p-pbar collisions at sqrt{s}=1.96 TeV. This search uses 320 pb-1 of the dataset accumulated by the upgraded Collider Detector at Fermilab. Events are selected that have a high-transverse momentum electron or muon, missing transverse energy, and two jets, on

Frank Simon

Using the forward time projection chambers of STAR we measure the centrality dependent Lambda and Anti-Lambda yields in d+Au collisions at \sqrt{s_{NN} = 200 GeV at forward and backward rapidities. The contributions of different processes to particle production and baryon transport are probed exploiting the inherent asymmetry of the d+Au system. While the d

Yves Décanini, Antoine Folacci

We develop the Hadamard renormalization of the stress-energy tensor for a massive scalar field theory defined on a general spacetime of arbitrary dimension. Our formalism could be helpful in treating some aspects of the quantum physics of extra spatial dimensions. More precisely, for spacetime dimension up to six, we explicitly describe the Hadamard renormal

Stephen P. Jordan, Edward Farhi, Peter W. Shor

Recently, there has been growing interest in using adiabatic quantum computation as an architecture for experimentally realizable quantum computers. One of the reasons for this is the idea that the energy gap should provide some inherent resistance to noise. It is now known that universal quantum computation can be achieved adiabatically using 2-local Hamilt

Peter Zweber

Using 20.7 pb^-1 of e+e- annihilation data taken at sqrt{s} = 3.671 GeV with the CLEO-c detector, precision measurements of the electromagnetic form factors of the charged pion, charged kaon, and proton have been made for timelike momentum transfers of |Q^2| = 13.48 GeV^2 by the reaction e+e- -> h+h-. The measurements are the first ever with identified pions

Jan M. Pawlowski

We discuss structural aspects of the functional renormalisation group. Flows for a general class of correlation functions are derived, and it is shown how symmetry relations of the underlying theory are lifted to the regularised theory. A simple equation for the flow of these relations is provided. The setting includes general flows in the presence of compos