December 2005 arXiv papers — page 37

Peter de Paepe, Jan Wiegerinck

In this paper we study the function algebra generated by z^2 and g^2 on a small closed disk centered at the origin of the complex plane. We prove, using a biholomorphic change of coordinates and already developed techniques in this area, that for a large class of functions g this algebra consists of all continuous functions on the disk.

Michael Röckner, Feng-Yu Wang

Various Poincare-Sobolev type inequalities are studied for a reaction-diffusion model of particle systems on Polish spaces. The systems we consider consist of finite particles which are killed or produced at certain rates, while particles in the system move on the Polish space interacting with one another (i.e. diffusion). Thus, the corresponding Dirichlet f

Kokoro Tanaka

We have a knot quandle and a fundamental class as invariants for a surface-knot. These invariants can be defined for a classical knot in a similar way, and it is known that the pair of them is a complete invariant for classical knots. In this paper, we compare a situation in surface-knot theory with that in classical knot theory, and prove the following: The

Andrea Colesanti

For a real-valued non-negative and log-concave function we introduce a notion of difference function; the difference function represents a functional analog on the difference body of a convex body. We prove a sharp inequality which bounds the integral of the difference function from above in terms of the integral of the function itself, and we characterize e

Gerrit van Dijk, Michael Pevzner

In the present note we discuss two different ring structures on the set of holomorphic discrete series of a causal symmetric space of Cayley type $G/H$ and we suggest a new interpretation of Rankin-Cohen brackets in terms of intertwining operators arising in the decomposition of tensor products of holomorphic discrete series representations.

Anna Sakovich

For any flag manifold G/T we obtain an explicit expression of its Levi-Civita connection with respect to any invariant Riemannian metric.

David Ginzburg, Joseph Hundley

This document describes the authors' current research project: the evaluation of a tower of Rankin-Selberg integrals on the group E_6. We recall the notion of a tower, and two known towers, making observations about how the integrals within a tower may be related to one another via formal manipulations, and offering a heuristic for how the L-functions sh

Joseph Hundley

If E(z,s) is the nonholomorphic Eisenstein series on the upper half plane, then for all y sufficiently large, E(z,s) has a "Siegel zero." That is E(z,β)=0 for a real number βjust to the left of one. We give a generalization of this result to Eisenstein series formed with real valued automorphic forms on a finite central covering of the adele points o

Thomas Cecil, Quo-Shin Chi, Gary Jensen

If $M$ is an isoparametric hypersurface in a sphere $S^n$ with four distrinct principal curvatures, then the principal curvatures $κ_1,...,κ_4$ can be ordered so that their multiplicities satisfy $m_1=m_2$ and $m_3=m_4$, and the cross-ratio $r$ of the principal curvatures (the Lie curvature) equals -1. In this paper, we prove that if $M$ is an irreducible co

Idrisse Khemar

We define a notion of isotropic surfaces in $\mathbb{O}$, i.e. on which some canonical symplectic forms vanish. Using the cross-product in $\mathbb{O}$ we define a map $ρ\colon Gr\_2(\mathbb{O})\to S^6$ from the Grassmannian of $\mathbb{O}$ to $S^6$. This allows us to associate to each surface $Σ$ of $\mathbb{O}$ a function $ρ\_Σ\colon Σ\to S^6$. Then we sho

F. Santos, A. Schuermann, F. Vallentin

In this short note we give a construction of an infinite series of Delone simplices whose relative volume grows super-exponentially with their dimension. This dramatically improves the previous best lower bound, which was linear.

Bernhard Keller

We show that the category of orbits of the bounded derived category of a hereditary category under a well-behaved autoequivalence is canonically triangulated. This answers a question by A. Buan, R. Marsh and I. Reiten which appeared in their study with M. Reineke and G. Todorov of the link between tilting theory and cluster algebras (closely related to work

J. Ross, R. P. Thomas

We prove that polarised manifolds that admit a constant scalar curvature Kähler (cscK) metric satisfy a condition we call slope semistability. That is, we define the slope $μ$ for a projective manifold and for each of its subschemes, and show that if $X$ is cscK then $μ(Z)\leμ(X)$ for all subschemes $Z$. This gives many examples of manifolds with Kähler clas

Rajan Murgan, Rafael I. Nepomechie, Chi Shi

Bethe Ansatz solutions of the open spin-1/2 integrable XXZ quantum spin chain at roots of unity with nondiagonal boundary terms containing two free boundary parameters have recently been proposed. We use these solutions to compute the boundary energy (surface energy) in the thermodynamic limit.

Jose J. Blanco-Pillado, Alberto Iglesias

We show that there exist massive perturbative states of the ten dimensional Green-Schwarz closed superstring that are stabilized against collapse due to presence of fermionic zero modes on its worldsheet. The excited fermionic degrees of freedom backreact on the spacetime motion of the string in the same way as a neutral persistent current would, rendering t

Carlos R. Mafra

The massless 4-point one-loop amplitude computation in the pure spinor formalism is shown to agree with the computation in the RNS formalism.

Eleonora Dell'Aquila

We study D-branes extended in T^2/Z_4 using the mirror description as a tensor product of minimal models. We describe branes in the mirror both as boundary states in minimal models and as matrix factorizations in the corresponding Landau-Ginzburg model. We isolate a minimal set of branes and give a geometric interpretation of these as D1-branes constrained t

You-Hua Luo, Zi-Ming Ge

In noncommutative space, we examine the problem of a noninteracting and harmonically trapped Bose-Einstein condensate, and derive a simple analytic expression for the effect of spatial noncommutativity on energy spectrum of the condensate. It indicates that the ground-state energy incorporating the spatial noncommutativity is reduced to a lower level, which

Thomas Mohaupt

We review old and recent results on subleading contributions to black hole entropy in string theory.

Luis J. Boya

After a brief review of string and $M$-Theory we point out some deficiencies. Partly to cure them, we present several arguments for ``$F$-Theory'', enlarging spacetime to $(2, 10)$ signature, following the original suggestion of C. Vafa. We introduce a suggestive Supersymmetric 27-plet of particles, associated to the exceptional symmetric hermitian s

J. Lukierski, M. Woronowicz

We describe the twisted space-time symmetries which imply the quantum Poincaré covariance of noncommutative Minkowski spaces, with constant, Lie algebraic and quadratic commutators. Further we present the relativistic and nonrelativistic particle models invariant respectively under twisted relativistic and twisted Galilean symmetries.

Zhou Bang-Rong

We complete the derivation of the Cornwall-Jackiw-Tomboulis effective potential for quark propagator at finite temperature and finite quark chemical potential in the real-time formalism of thermal field theory and in Landau gauge. In the approximation that the function $A(p^2)$ in inverse quark propagator is replaced by unity, by means of the running gauge c

Zhou Bang-Rong

By means of a formal expression of the Cornwall-Jackiw-Tomboulis effective potential for quark propagator at finite temperature and finite quark chemical potential, we derive the real-time thermal Schwinger-Dyson equation for quark propagator in Landau gauge. Denote the inverse quark propagator by $A(p^2)\not{p}-B(p^2)$, we argue that, when temperature $T$ i

Zhou Bang-Rong

It is shown that, by means of canonical operator approach, the Ward-Takahashi identity (WTI) at finite temperature $T$ and finite chemical potential $μ$ for complete vectorial vertex and complete fermion propagator can be simply proven, rigorously for Quantum Electrodynamics (QED) and approximately for Quantum Chromodynamics (QCD) where the ghost effect in t

Yoshitaka Okumura

$U(n\otimes m)\ast$ gauge field theory on noncommutative spacetime is formulated and the standard-like model with the symmetry ${\text{U}(3_c\otimes 2\otimes 1_{\text{\scriptsize$Y$}})\ast}$ is reconstructed based on it. $\text{U}(n+m)\ast$ gauge group reduces to $\text{U}(n+m)$ on the commutative spacetime which is not ${\text{U}}(N), (N=n+m)$ but isomorphi

John Ellis

Some personal comments are given on some of the exciting interfaces between the physics of HERA and the LHC. These include the quantitative understanding of perturbative QCD, the possible emergence of saturation phenomena and the Colour-Glass Condensate at small x and large Q^2, the link between forward physics and ultra-high-energy cosmic rays, and new LHC

M. J. Dinsdale

We study the effect of optimising the renormalisation and factorisation scales on perturbative calculations of event shape means defined in the Breit frame of ep DIS. Unlike in the case of e^+e^- event shape means, this has only a small effect on the NLO QCD predictions and a large power correction is still required to fit the data. However, if separate reno

Ilja Dorsner, Pavel Fileviez Perez, Ricardo Gonzalez Felipe

Several phenomenological and cosmological aspects of a minimal extension of the Georgi-Glashow model, where the Higgs sector is composed by 5_H, 15_H, and 24_H, are studied. It is shown that the constraints coming from the unification of gauge interactions up to two-loop level predict light scalar leptoquarks. In this GUT scenario, the upper bound on the tot

T. Huber, S. Schilling

We present recent results of the rare semileptonic decay B -> X_s l+ l-. We particularly focus on higher order electroweak corrections in the Standard Model (SM) as well as O(alpha_s) corrections in Two-Higgs-doublet models (THDM), both of which are computed within an effective field theory approach. The calculation of higher order electroweak corrections re

Alejandro Rivero

We note that hadronic susy (empirical quark-diquark) symmetry can be expanded into the lepton sector, and that for three generations the counting of degrees of freedom is the one we need to build charged supermultiplets. For this to cure hierarchy, Higgs modeling becomes restricted.

D. Kekez, D. Klabucar

The study of light pseudoscalar quark-antiquark bound states in the Dyson-Schwinger approach with the effective QCD coupling enhanced by the interplay of the dimension 2 gluon condensate <A^2> and dimension 4 gluon condensate <F^2>, is extended to the eta-eta&#39; complex. We include the effects of the gluon axial anomaly into the Dyson-Schwinger approach to

Alex Casanova, Euro Spallucci

It is generally believed that mini black holes decay by emitting elementary particles with a black body energy spectrum. The original calculation lead to the conclusion that about the 90% of the black hole mass is radiated away in the form of photons, neutrinos and light leptons, mainly electrons and muons. With the advent of String Theory, such a scenario m

D. L. Bennett, M. Blagojevic, B. Cvetkovic, A. Borstnik Bracic

Contents: 1. Can MPP Together with Weinberg-Salam Higgs Provide Cosmological Inflation? (D.L. Bennett and H.B. Nielsen) 2. Conserved Charges in 3d Gravity With Torsion (M. Blagojevic and B. Cvetkovic) 3. Mass Matrices of Quarks and Leptons in the Approach Unifying Spins and Charges (A. Borstnik Bracic and N.S. Mankoc Borstnik) 4. Dark Matter From Encapsulate

K. G. Chetyrkin, J. H. Kühn, C. Sturm

We present the matching condition for the strong coupling contant alpha_s at a heavy quark threshold to four loops in the modified minimal subtraction scheme. Our results lead to further decrease of the theoretical uncertainty of the evolution of the strong coupling constant through heavy quark thresholds. Using a low energy theorem we furthermore derive the

Andrzej J. Buras, Robert Fleischer, Stefan Recksiegel, Felix Schwab

The $B\toπK$ decays with significant electroweak penguin contributions show a puzzling pattern. We explore this &#34;$B\toπK$ puzzle&#34; through a systematic strategy. The starting point, which is essentially unaffected by electroweak penguins, is the determination of the angle $γ$ of the unitarity triangle through the CP-violating $B^0_d\toπ^+π^-$, $B^0_d\

Y. Schroder, M. Steinhauser

We compute the matching relation for the strong coupling constant within the framework of QCD up to four-loop order. This allows a consistent five-loop running (once the $β$ function is available to this order) taking into account threshold effects. As a side product we obtain the effective coupling of a Higgs boson to gluons with five-loop accuracy.

M. A. Braun

An effective non-local quantum field theory is constructed, which describes interaction of pomerons in the high-coloured QCD. The theory includes both splitting and merging triple pomeron vertexes and diagrams with pomeronic loops. The Schwinger-Dyson equations for the &#39;physical&#39; pomeron are written. Conformal invariance allows to reduce the theory t

Jun He, Yu-bing Dong

We use a diquark model of the nucleon to calculate the electromagnetic form factors of the nucleon described as a scalar and axialvector diquark bound state. We provide an analysis of the zero-mode contribution in the diquark model. We find there are zero-mode contributions to the form factors arising from the instantaneous part of the quark propagator, whic

Cristina Manuel

We discuss some low energy properties of color-flavor locked (CFL) superconductors. First, we study how an external magnetic field affects their Goldstone physics in the chiral limit, stressing that there is a long-range component of the field that penetrates the superconductor. We note that the most remarkable effect of the applied field is giving a mass to

N. N. Nikolaev, F. F. Pavlov

The spin filtering in storage rings is based on the multiple passage of a stored beam through a polarized internal gas target. Apart from the polarization by transmission, a unique geometrical feature of interaction with the target in such a filtering process, pointed out by H.O. Meyer \cite{Meyer}, is a scattering of stored particles within the beam. A rota

E. M. Lipmanov

Two guiding new phenomenological flavor and flavor-electroweak ideas are expounded in this paper: (I) Oppositeness relation between neutrino and Charged Lepton Mass-Degeneracy-Deviation quantities. With inputs from the mass and neutrino oscillation data, it enables two independent estimations of the neutrino masses m =(0.11-0.30)eV and m =(0.11-0.16) eV. Sma

L. Herrera, A. Di Prisco, W. Barreto

We present a numerical model of a collapsing radiating sphere, whose boundary surface undergoes bouncing due to a decreasing of its inertial mass density (and, as expected from the equivalence principle, also of the ``gravitational&#39;&#39; force term) produced by the ``inertial&#39;&#39; term of the transport equation. This model exhibits for the first tim

J. Mark Heinzle, Claes Uggla

We investigate the dynamics of spatially homogeneous solutions of the Einstein-Vlasov equations with Bianchi type I symmetry by using dynamical systems methods. All models are forever expanding and isotropize toward the future; toward the past there exists a singularity. We identify and describe all possible past asymptotic states; in particular, on the past

Joan Sola

The experimental evidence that the equation of state (EOS) of the dark energy (DE) could be evolving with time/redshift (including the possibility that it might behave phantom-like near our time) suggests that there might be dynamical DE fields that could explain this behavior. We propose, instead, that a variable cosmological term (including perhaps a varia

Carlos F. Sopuerta, Pablo Laguna

The description of extreme-mass-ratio binary systems in the inspiral phase is a challenging problem in gravitational wave physics with significant relevance for the space interferometer LISA. The main difficulty lies in the evaluation of the effects of the small body&#39;s gravitational field on itself. To that end, an accurate computation of the perturbatio

Iver Brevik, Jon-Mattis Borven, Sebastian Ng

We assume a flat brane located at y=0, surrounded by an AdS space, and consider the 5D Einstein equations when the energy flux component of the energy-momentum tensor is related to the Hubble parameter through a constant Q. We calculate the metric tensor, as well as the Hubble parameter on the brane, when Q is small. As a special case, if the brane is tensio

Benedict M. N. Carter, Alex B. Nielsen

The static potential for a massless scalar field shares the essential features of the scalar gravitational mode in a tensorial perturbation analysis about the background solution. Using the fluxbrane construction of [8] we calculate the lowest order of the static potential of a massless scalar field on a thin brane using series solutions to the scalar field&

Charles H. -T. Wang

A discussion is given of recent developments in canonical gravity that assimilates the conformal analysis of gravitational degrees of freedom. The work is motivated by the problem of time in quantum gravity and is carried out at the metric and the triad levels. At the metric level, it is shown that by extending the Arnowitt-Deser-Misner (ADM) phase space of

Edgard Casal de Rey Neto

We take arbitrary gravitational perturbations of a 5d spacetime and reduce it to the form an axially symmetric warped braneworld. Then, we write the filed equations for the linearized gravity perturbations. We obtain the equations that describes the graviton, gravivector and the graviscalar fluctuations and analyse the effects of the Schrödinger potentials t

Brahim Hamid, Ted Herman, Morten Mjelde

This technical report documents the poster session of SSS 2005, the Symposium on Self-Stabilizing Systems published by Springer as LNCS volume 3764. The poster session included five presentations. Two of these presentations are summarized in brief abstracts contained in this technical report.

Nima Sarshar, Xiaolin Wu

We are interested in how to best communicate a real valued source to a number of destinations (sinks) over a network with capacity constraints in a collective fidelity metric over all the sinks, a problem which we call joint network-source coding. It is demonstrated that multiple description codes along with proper diversity routing provide a powerful soluti

Marek W. Gutowski

There is no proof yet of convergence of Genetic Algorithms. We do not supply it too. Instead, we present some thoughts and arguments to convince the Reader, that Genetic Algorithms are essentially bound for success. For this purpose, we consider only the crossover operators, single- or multiple-point, together with selection procedure. We also give a proof t

Charles H. Patterson

Experimental studies of Zn1-xCoxO as thin films or nanocrystals have found ferromagnetism and Curie temperatures above room temperature and that p- or n-type doping of Zn1-xCoxO can change its magnetic state. Bulk Zn1-xCoxO with a low defect density and x in the range used in experimental thin film studies exhibits ferromagnetism only at very low temperature

S. Vincent-Bonnieu, R. Höhler, S. Cohen-Addad

Like emulsions, pastes and many other forms of soft condensed matter, aqueous foams present slow mechanical relaxations when subjected to a stress too small to induce any plastic flow. To identify the physical origin of this viscoelastic behaviour, we have simulated how dry disordered coarsening 2D foams respond to a small applied stress. We show that the me

Dipti Sharma, Germano S. Iannacchione

A high-resolution calorimetric spectroscopy study has been performed on pure glycerol and colloidal dispersions of an aerosil in glycerol covering a wide range of temperatures from 300 K to 380 K, deep in the liquid phase of glycerol. The colloidal glycerol+aerosil samples with 0.05, 0.10, and 0.20 mass fraction of aerosil reveal glassy, activated dynamics a

Sumiyoshi Abe, A. K. Rajagopal

A quantum-mechanical version of Einstein&#39;s 1905 theory of Brownian motion is presented. Starting from the Hamiltonian dynamics of an isolated composite of objective and environmental systems, subdynamics for the objective system is derived in the spirit of Einstein. The resulting master equation is found to have the Lindblad structure.

Stefan Klumpp, Reinhard Lipowsky

The movement of motor particles consisting of one or several molecular motors bound to a cargo particle is studied theoretically. The particles move on patterns of immobilized filaments. Several patterns are described for which the motor particles undergo non-directed but enhanced diffusion. Depending on the walking distance of the particles and the mesh siz

N. M. R. Peres, F. Guinea, A. H. Castro Neto

Two-dimensional carbon, or graphene, is a semi-metal that presents unusual low-energy electronic excitations described in terms of Dirac fermions. We analyze in a self-consistent way the effects of localized (impurities or vacancies) and extended (edges or grain boundaries) defects on the electronic and transport properties of graphene. On the one hand, poin

L. Latessa, A. Pecchia, A. Di Carlo

We report density-functional theory (DFT), atomistic simulations of the non-equilibrium transport properties of carbon nanotube (CNT) field-effect transistors (FETs). Results have been obtained within a self-consistent approach based on the non-equilibrium Green&#39;s functions (NEGF) scheme. Our attention has been focused on a new kind of devices, the so ca

Sumathi Rao

We introduce and motivate the study of quantum spin chains on a one-dimensional lattice. We classify the varieties of methods that have been used to study these models into three categories, - a) exact methods to study specific models b) field theories to describe fluctuations about the classical ordered phases and c) numerical methods. We then discuss the $

Santanu Sinha, S. B. Santra

Directed spiral percolation (DSP) is a new percolation model with crossed external bias fields. Since percolation is a model of disorder, the effect of external bias fields on the properties of disordered systems can be studied numerically using DSP. In DSP, the bias fields are an in-plane directional field ($E$) and a field of rotational nature ($B$) applie

A. P. Serebrov, V. T. Lebedev, A. V. Lepekhin

We propose a new method to form very cold neutron (VCN) beams collimated and monochromatic without usual losses of flux by three or more orders in magnitude due to narrow line cutting from energy and angular spectra. To this purpose ultracold neutrons should be accelerated in gravity field to shift their phase volume in momentum space without volume expansio

Pawel Zin, Jan Chwedenczuk, Marek Trippenbach

Bragg diffraction divides a Bose-Einstein condensate into two overlapping components, moving with respect to each other with high momentum. Elastic collisions between atoms from distinct wave packets can significantly deplete the condensate. Recently Ziń {\it et al.} (Phys. Rev. Lett. {\bf 94}, 200401 (2005)) have introduced a model of two counter-propagatin

H. Kang, Jong Soo Lim, J. -Y. Fortin, J. Choi

We study motion of domain wall defects in a fully frustrated Josephson-unction ladder system, driven by small applied currents. For small system sizes, the energy barrier E_B to the defect motion is computed analytically via symmetry and topological considerations. More generally, we perform numerical simulations directly on the equations of motion, based on

G. Knebel, D. Aoki, D. Braithwaite, B. Salce

We report on detailed ac calorimetry measurements under high pressure and magnetic field of CeRhIn5. Under hydrostatic pressure the antiferromagnetic order vanishes near p_c*=2 GPa due to a first order transition. Superconductivity is found for pressures above 1.5 GPa inside the magnetic ordered phase. However, the superconductivity differ from the pure homo

Y. J. Uemura

In the quest for primary factors which determine the transition temperature $T_{c}$ of high-$T_{c}$ cuprate superconductors (HTSC), we develop a phenomenological picture combining experimental results from muon spin relaxation ($μ$SR), neutron and Raman scattering, and angle-resolved photoemission (ARPES) measurements, guided by an analogy with superfluid $^

Michael Freedman, Chetan Nayak, Kevin Walker

We show how a universal gate set for topological quantum computation in the Ising TQFT, the non-Abelian sector of the putative effective field theory of the $ν=5/2$ fractional quantum Hall state, can be implemented. This implementation does not require overpasses or surgery, unlike the construction of Bravyi and Kitaev, which we take as a starting point. How

Carl-Olof Almbladh

The many-body theory of photoemission in solids is reviewed with emphasis on methods based on response theory. The classification of diagrams into loss and no-loss diagrams is discussed and related to Keldysh path-ordering book-keeping. Some new results on energy losses in valence-electron photoemission from free-electron-like metal surfaces are presented. A

Michael Freedman, Chetan Nayak, Kevin Walker

The Pfaffian state, which may describe the quantized Hall plateau observed at Landau level filling fraction $ν= 5/2$, can support topologically-protected qubits with extremely low error rates. Braiding operations also allow perfect implementation of certain unitary transformations of these qubits. However, in the case of the Pfaffian state, this set of unita

Yufeng Zhang, Ayako Yamamoto, Mitsuru Izumi

This paper has been withdrawn by the authors due to lack of significant consideration.

V. A. Khodel, M. V. Zverev, Victor M. Yakovenko

Low-temperature thermodynamic properties of strongly interacting Fermi liquids with fermion condensate are investigated. We demonstrate that the spin susceptibility of these systems exhibits the Curie-Weiss law, and the entropy contains a temperature-independent term. The excessive entropy is released at the superconducting transition, enhancing the specific

Daniele Vilone, Claudio Castellano, Paolo Politi

We consider the growth of a vicinal crystal surface in the presence of a step-edge barrier. For any value of the barrier strength, measured by the length l_es, nucleation of islands on terraces is always able to destroy asymptotically step-flow growth. The breakdown of the metastable step-flow occurs through the formation of a mound of critical width proport

Sasa Ratkovic, Madappa Prakash, James M. Lattimer

Close binary systems of compact stars, due to the emission of gravitational radiation, may evolve into a phase in which the less massive star transfers mass to its companion. We describe mass transfer by using the model of Roche lobe overflow, in which mass is transferred through the first, or innermost, Lagrange point. Under conditions in which gravity is s

Jennifer A. Johnson, Inese I. Ivans, Peter B. Stetson

We have observed ten red giant stars in four old Large Magellanic Cloud globular clusters with the high-resolution spectrograph MIKE on the Magellan Landon Clay 6.5-m telescope. The stars in our sample have up to 20 elemental abundance determinations for the alpha-, iron-peak, and neutron-capture element groups. We have also derived abundances for the light

Zosia A. C. Krusberg, Brian Chaboyer

Photometric UBVI CCD photometry is presented for NGC 188 and Berkeley 17. Color-magnitude diagrams (CMDs) are constructed and reach well past the main-sequence turn-off for both clusters. Cluster ages are determined by means of isochrone fitting to the cluster CMDs. These fits are constrained to agree with spectroscopic metallicity and reddening estimates. C

Michael R. Blanton

In the six billion years between redshifts z=1 and z=0.1, galaxies change due to the aging of their stellar populations, the formation of new stars, and mergers with other galaxies. Here I explore the relative importance of these various effects, finding that while mergers are likely to be important for the red galaxy sequence they are unlikely to affect mor

J. Horak, V. Karas

We study polarization from scattering of light on a cloud in radial motion along the symmetry axis of an accretion disk. Radiation drag from the disk and gravitational attraction of the central black hole are taken into account, as well as the effect of the cloud cooling in the radiation field. This provides us with a self-consistent toy-model for predicted

C. Qi, D. J. Wilner, N. Calvet, T. L. Bourke

We present the first images of the 691.473 GHz CO J=6-5 line in a protoplanetary disk, obtained along with the 690 GHz dust continuum, toward the classical T Tauri star TW Hya using the Submillimeter Array. Imaging in the CO J=6-5 line reveals a rotating disk, consistent with previous observations of CO J=3-2 and 2-1 lines. Using an irradiated accretion disk

Gian Luigi Granato, Luigi Danese

We point out that in Granato & Danese 1994 and Granato et al. 1997 we predicted maximum observable sizes for the putative torus in NGC1068 of 10-20 pc, not &#34;hundreds of parsecs&#34; as stated by M. Elitzur in astro-ph/0512025.

Janine Heinmueller, Patrick Petitjean, Cedric Ledoux, Sara Caucci

We present UVES observations of the log N(HI)= 21.7 damped Lyman-alpha system at z=2.03954 towards the quasar PKS 0458-020. HI Lyman-alpha emission is detected in the center of the damped Lyman-alpha absorption trough. Metallicities are derived for MgII, SiII, PII, CrII, MnII, FeII and ZnII and are found to be -1.21\pm0.12, -1.28\pm0.20, -1.54\pm0.11, -1.66\

Mark R. Chun, Soheila Gharanfoli, Varsha P. Kulkarni, Marianne Takamiya

We have carried out a high angular resolution near-infrared imaging study of the fields of 6 quasars with 7 strong absorption line systems at z < 0.5, using the Hokupa'a adaptive optics system and the QUIRC near-infrared camera on the Gemini-North telescope. These absorption systems include 4 classical damped Lyman-alpha absorbers (DLAs), 2 sub-DLAs, and one

A. J. R. Prentice

I report a model for the formation of Saturn&#39;s family of mid-sized icy moons to coincide with the first flypast of Rhea by the Cassini Orbiter spacecraft on 26 November 2005. It is proposed that these moons had condensed from a concentric family of orbiting gas rings that were cast off some 4600 Myr ago by the contracting proto-Saturnian cloud. Numerical

D. J. Saikia, C. Konar, V. K. Kulkarni

We report the discovery of a double-double radio galaxy (DDRG), J0041+3224, with the Giant Metrewave Radio Telescope (GMRT) and subsequent high-frequency observations with the Very Large Array (VLA). The inner and outer doubles are aligned within about 4 deg and are reasonably collinear with the parent optical galaxy. The outer double has a steeper radio spe

P. Cabella, F. K. Hansen, M. Liguori, D. Marinucci

We propose a fast and efficient bispectrum statistic for Cosmic Microwave Background (CMB) temperature anisotropies to constrain the amplitude of the primordial non-Gaussian signal measured in terms of the non-linear coupling parameter f_NL. We show how the method can achieve a remarkable computational advantage by focussing on subsets of the multipole confi

Alessandra Lamastra, G. Cesare Perola, Giorgio Matt

The fraction of AGN with photoelectric absorption in the X-rays ranging from NH of 10^{22} up to about 10^{24} cm^{-2} (Compton-thin) appears observationally to be anticorrelated to their luminosity Lx. This recently found evidence is used to investigate the location of the absorbing gas. The molecular torus invoked in the unified picture of AGN, while it ca

Tim Freyer, Gerhard Hensler, Harold W. Yorke

We continue our numerical analysis of the morphological and energetic influence of massive stars on their ambient interstellar medium for a 35 solar mass star that evolves from the main sequence through red supergiant and Wolf-Rayet phases, until it ultimately explodes as a supernova. We find that structure formation in the circumstellar gas during the early

M. Bellazzini, M. Correnti, F. R. Ferraro, L. Monaco

We present a statistically decontaminated Color Magnitude Diagram of a 1 deg X 1 deg field in the core of the Sagittarius dSph galaxy. Coupling this CMD with the most recent metallicity distributions obtained from high resolution spectroscopy we derive robust constraints on the mean age of the stellar population that dominates the galaxy (Pop A). Using three

Dmitry Bizyaev, Verne V. Smith, Jose Arenas, Doug Geisler

We present results from a campaign of multiple epoch echelle spectroscopy of relatively faint (V = 9.5-13.5 mag) red giants observed as potential astrometric grid stars for the Space Interferometry Mission (SIM PlanetQuest). Data are analyzed for 775 stars selected from the Grid Giant Star Survey spanning a wide range of effective temperatures (Teff), gravit

Walter Dehnen, Andrew King

Low-mass X-ray binaries (LMXBs), which occur in old stellar populations, have velocities exceeding those of their parent distribution by at least 20 km/s. This makes them ideal probes for dark matter, in particular in dwarf spheroidals (dSph), where the LMXBs should penetrate well outside the visible galaxy. We argue that the most likely explanation of the o

M. Mugrauer, R. Neuhäuser, T. Mazeh, E. Guenther

We carry out a systematic search campaign for wide companions of exoplanet host stars to study their multiplicity and its influence on the long-term stability and the orbital parameters of the exoplanets. We have already found 6 wide companions, raising the number of confirmed binaries among the exoplanet host stars to 20 systems. We have also searched for w

M. Kuemmel, S. S. Larsen, J. R. Walsh

The Advanced Camera for Surveys (ACS) enables low resolution slitless spectroscopic imaging in the three channels. The most-used modes are grism imaging with the WFC and the HRC at a resolution of 40 and 24 A/pixel, respectively. In the far UV there are two prisms for the SBC and a prism for the HRC in the near-UV. An overview of the slitless spectroscopic m

S. S. Larsen, M. Kuemmel, J. R. Walsh

The Advanced Camera for Surveys is equipped with three prisms in the Solar Blind (SBC) and High Resolution (HRC) Channels, which together cover the 1150 - 3500 A range, albeit at highly non-uniform spectral resolution. We present new wavelength- and flux calibrations of the SBC (PR110L and PR130L) and HRC (PR200L) prisms, based on calibration observations ob

J. R. Walsh, M. Kuemmel, S. S. Larsen

The software package aXe provides comprehensive spectral extraction facilities for all the slitless modes of the ACS, covering the Wide Field Channel (WFC) grism, the High Resolution Channel (HRC) grism and prism and the Solar Blind Channel (SBC) prisms. The latest developments to the package apply to all ACS slitless modes leading to improved spectral extra

John Meaburn

A review of recent observations of the kinematics of six objects that represent the broad range of phenomena called planetary nebulae (PNe) is presented. It is demonstrated that Hubble-type outflows are predominant, consequently it is argued that ballistic ejections from the central stars could have dominated the dynamical effects of the fast winds in severa

A. Caratti o Garatti, T. Giannini, B. Nisini, D. Lorenzetti

We present a NIR analysis of a sample of H2 outflows from young embedded sources to compare the physical properties and cooling mechanisms of the different flows. The sample comprises 23 outflows driven by Class 0 and I sources having low-intermediate luminosity. We have obtained narrow band images in H2 2.12um and FeII 1.64um and spectroscopic observations

Óscar J. C. Dias, Paulo M. Sá

We present and discuss the analytical r-mode solution to the linearized hydrodynamic equations of a slowly rotating, Newtonian, barotropic, non-magnetized, perfect-fluid star in which the gravitational radiation reaction force is present.

Rebecca Centeno, Manuel Collados, Javier Trujillo Bueno

Velocity oscillations in sunspot umbrae have been measured simultaneously in two spectral lines: the photospheric Silicon I 10827 A line and the chromospheric Helium I 10830 A multiplet. From the full Stokes inversion of temporal series of spectropolarimetric observations we retrieved, among other parameters, the line of sight velocity temporal variations at

U. Mukherjee, B. Paul

High Mass X-ray Binary Pulsars (HMXBP), in which the companion star is a source of supersonic stellar wind, provide a laboratory to probe the velocity and density profile of such winds. Here, we have measured the variation of the absorption column density along with other spectral parameters over the binary orbit for two HMXBP in elliptical orbits, as observ

D. Gouliermis, W. Brandner, Th. Henning

We report on the serendipitous discovery of ~ 500 low-mass candidate PMS stars in the vicinity of the stellar association LH 52 in the Large Magellanic Cloud. We present evidence that the red faint sequence of these stars seen in the CMD of LH 52 from HST/WFPC2 observations belongs only to the association and follows almost perfectly isochrone models for PMS

E. Brannigan, M. Takami, A. Chrysostomou, J. Bailey

We demonstrate that artificial bipolar structure can be detected using spectro-astrometry when the point spread function (PSF) of a point source suffers distortion in a relatively wide slit. Spectro-astrometry is a technique which allows us to probe the spatial structure of astronomical sources on milliarcsecond scales making it possible to detect close bina