Corotational Instability of Inertial-Acoustic Modes in Black Hole Accretion Discs and Quasi-Periodic OscillationsWe study the global stability of non-axisymmetric p-modes (also called inertial-acoustic modes) trapped in the inner-most regions of accretion discs around black holes. We show that the lowest-order…Dong Lai, David Tsang·Oct 1, 2008SaveLearn
Dynamical Dark Energy simulations: high accuracy Power Spectra at high redshiftAccurate predictions on non--linear power spectra, at various redshift z, will be a basic tool to interpret cosmological data from next generation mass probes, so obtaining key information on Dark…Luciano Casarini, Andrea V. Maccio', Silvio A. Bonometto·Oct 1, 2008SaveLearn
Effect of Peculiar Motion in Weak LensingWe study the effect of peculiar motion in weak gravitational lensing. We derive a fully relativistic formula for the cosmic shear and the convergence in a perturbed Friedmann Universe. We find a new…Camille Bonvin·Oct 1, 2008SaveLearn
Pulsating B and Be stars in the Magellanic CloudsStellar pulsations in main-sequence B-type stars are driven by the κ-mechanism due to the Fe-group opacity bump. The current models do not predict the presence of instability strips in the B…P. D. Diago, J. Gutiérrez-Soto, J. Fabregat et al.·Oct 1, 2008SaveLearn
Higher neutrino mass allowed if Cold Dark Matter and Dark Energy are coupledCosmological limits on neutrino masses are softened, by more than a factor 2, if Cold Dark Matter (CDM) and Dark Energy (DE) are coupled. In turn, a neutrino mass yielding Ων up to 0.20…G. La Vacca, S. A. Bonometto, L. P. L. Colombo·Oct 1, 2008SaveLearn
Why do cosmological perturbations look classical to us?According to the inflationary scenario of cosmology, all structure in the Universe can be traced back to primordial fluctuations during an accelerated (inflationary) phase of the very early Universe.…Claus Kiefer, David Polarski·Oct 1, 2008SaveLearn
Models and Observations of Sunspot PenumbraeThe mysteries of sunspot penumbrae have been under an intense scrutiny for the past 10 years. During this time, some models have been proposed and refuted, while the surviving ones had to be…J. M. Borrero·Oct 1, 2008SaveLearn
Galactic Nonlinear Dynamic ModelWe develop a model for spiral galaxies based on a nonlinear realization of the Newtonian dynamics starting from the momentum and mass conservations in the phase space. The radial solution exhibits a…C. A. M. de Melo, S. T. Resende·Oct 1, 2008SaveLearn
Clathration of Volatiles in the Solar Nebula and Implications for the Origin of Titan's atmosphereWe describe a scenario of Titan's formation matching the constraints imposed by its current atmospheric composition. Assuming that the abundances of all elements, including oxygen, are solar in…Olivier Mousis, Jonathan I. Lunine, Caroline Thomas et al.·Oct 1, 2008SaveLearn
Simulating hydromagnetic processes in star formation: introducing ambipolar diffusion into an adaptive mesh refinement codeGiven the importance of simulating hydromagnetic processes that impact star formation, we have earlier developed a 3D adaptive mesh approach that allows us to include hydromagnetic processes during…D. F. Duffin, R. E. Pudritz·Oct 1, 2008SaveLearn
DMTPC: a new apparatus for directional detection of Dark MatterDirectional detection of Dark Matter allows for unambiguous direct detection of WIMPs as well as discrimination between various Dark Matter models in our galaxy. The DMTPC detector is a low-pressure…G. Sciolla, A. Lee, J. Battat et al.·Oct 1, 2008SaveLearn
Saturn Forms by Core Accretion in 3.4 MyrWe present two new in situ core accretion simulations of Saturn with planet formation timescales of 3.37 Myr (model S0) and 3.48 Myr (model S1), consistent with observed protostellar disk lifetimes.…Sarah E. Dodson-Robinson, Peter Bodenheimer, Gregory Laughlin et al.·Oct 1, 2008SaveLearn
STIS Imaging of the HR 4796A Circumstellar Debris RingWe have obtained high spatial resolution imaging observations of the HR 4796A circumstellar debris dust ring using the broad optical response of the Hubble Space Telescope Imaging Spectrograph in…G. Schneider, A. J. Weinberger, E. E. Becklin et al.·Oct 1, 2008SaveLearn
Prospects for the Detection of the Deep Solar Meridional CirculationWe perform helioseismic holography to assess the noise in p-mode travel-time shifts which would form the basis of inferences of large-scale flows throughout the solar convection zone. We also derive…D. C. Braun, A. C. Birch·Oct 1, 2008SaveLearn
The C/O ratio at low metallicity: constraints on early chemical evolution from observations of Galactic halo starsWe present new measurements of the abundances of carbon and oxygen derived from high-excitation C I and O I absorption lines in metal-poor halo stars, with the aim of clarifying the main sources of…D. Fabbian, P. E. Nissen, M. Asplund et al.·Oct 1, 2008SaveLearn
Hadronic Production of Gamma Rays and Starburst GalaxiesThe Milky Way has been estabished to emit gamma rays. These gamma rays are presumably dominated by decays of neutral pions, although inverse Compton scatterings and bremsstrahlung also contribute. It…Niklas Karlsson·Oct 1, 2008SaveLearn
Halo stochasticity in global clustering analysisIn the present work we study the statistics of haloes, which in the halo model determines the distribution of galaxies. Haloes are known to be biased tracer of dark matter, and at large scales it is…Silvia Bonoli, Ue-Li Pen·Oct 1, 2008SaveLearn
Long lived central engines in Gamma Ray BurstsThe central engine of Gamma Ray Bursts may live much longer than the duration of the prompt emission. Some evidence of it comes from the presence of strong precursors, post-cursors, and X-ray flares…G. Ghisellini·Oct 1, 2008SaveLearn
The ACS Nearby Galaxy Survey Treasury II. Young Stars and their Relation to Halpha and UV Emission Timescales in the M81 Outer DiskWe have obtained resolved stellar photometry from Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) observations of a field in the outer disk of M81 as part of the ACS Nearby Galaxy…Stephanie M. Gogarten, Julianne J. Dalcanton, Benjamin F. Williams et al.·Oct 1, 2008SaveLearn
Dust Settling in Magnetorotationally-Driven Turbulent Discs I: Numerical Methods and Evidence for a Vigorous Streaming Instability(Abridged) In this paper we have used the RIEMANN code for computational astrophysics to study the interaction of a realistic distribution of dust grains with gas in a vertically stratified…Dinshaw S. Balsara, David A. Tilley, Terrence Rettig et al.·Oct 1, 2008SaveLearn
Mass-losing accretion discs around supermassive black holesWe study the effects of outflow/wind on the gravitational stability of accretion discs around supermassive black holes using a set of analytical steady-state solutions. Mass-loss rate by the outflow…Fazeleh Khajenabi·Oct 1, 2008SaveLearn
Mass estimate of the XTE J1650-500 black hole from the Extended Orbital Resonance Model for high-frequency QPOsXTE J1650-500 is a Galactic black-hole binary system for which at least one high-frequency QPO at 250Hz was reported. Moreover there are indications that the system harbours a near-extreme Kerr…Petr Slany, Zdenek Stuchlik·Oct 1, 2008SaveLearn
Generalized Maximum Likelihood Method for Ultrahigh Energy Cosmic RaysThe Maximum Likelihood Method is generalized to include effects important for UHECR applications. The new approach can incorporate source distance constraints implied by the observed CR energy and…Glennys R. Farrar·Oct 1, 2008SaveLearn
Time dependent modelisation of TeV blazars by a stratified jet modelWe present a new time-dependent inhomogeneous jet model of non-thermal blazar emission. Ultra-relativistic leptons are injected at the base of a jet and propagate along it. We assume continuous…Timothé Boutelier, Gilles Henri, Pierre-Olivier Petrucci·Oct 1, 2008SaveLearn
Open Clusters IC 4665 and Cr 359 and a Probable Birthplace of the Pulsar PSR B1929+10Based on the epicyclic approximation, we have simulated the motion of the young open star clusters IC 4665 and Collinder 359. The separation between the cluster centers is shown to have been minimal…V. V. Bobylev·Oct 1, 2008SaveLearn