Multi-frequency investigation of the parsec- and kilo-parsec-scale radio structures in high-redshift quasar PKS 1402+044We investigate the frequency-dependent radio properties of the jet of the luminous high-redshift (z = 3.2) radio quasar PKS 1402+044 (J1405+0415) by means of radio interferometric observations. The…J. Yang, L. I. Gurvits, A. P. Lobanov et al.·Oct 1, 2008SaveLearn
Rotation and Activity in Late-type M DwarfsWe have examined the relationship between rotation and activity in 14 late-type (M6-M7) M dwarfs, using high resolution spectra taken at the Keck Observatory and flux-calibrated spectra from the…Andrew A. West, Gibor Basri·Oct 1, 2008SaveLearn
Exploring the Virgo Stellar Stream with SEKBO Survey RR Lyrae StarsA subset of the RR Lyrae (RRL) candidates identified from the Southern Edgeworth-Kuiper Belt Object (SEKBO) survey data has been followed up photometrically (n=106) and spectroscopically (n=51).…Sayuri L Prior, G S Da Costa, Stefan C Keller et al.·Oct 1, 2008SaveLearn
Large HI structures linked to southern O-type starsIn our search for interstellar bubbles around massive stars we analyze the environs of the O-type stars HD 38666, HD 124979, HD 163758, and HD 171589. The location of the stars, which are placed far…M. C. Martín, C. E. Cappa, G. A. Romero·Oct 1, 2008SaveLearn
Spectroscopic Confirmation of a Massive Red-Sequence-Selected Galaxy Cluster at z = 1.34 in the SpARCS-South Cluster SurveyThe Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a z'-passband imaging survey, consisting of deep (z' ~ 24 AB) observations made from both hemispheres using the CFHT 3.6m…Gillian Wilson, Adam Muzzin, H. K. C. Yee et al.·Oct 1, 2008SaveLearn
Telescope Optics and Weak Lensing: PSF Patterns due to Low Order AberrationsIn weak lensing investigations, galaxy shapes are deconvolved for the effects of the point spread function (PSF) using stellar images. In this paper we use physical models of the telescope optics to…Mike Jarvis, Paul Schechter, Bhuvnesh Jain·Oct 1, 2008SaveLearn
Fluctuations in the High-Redshift Lyman-Werner Background: Close Halo Pairs as the Origin of Supermassive Black HolesThe earliest generation of stars and black holes must have established an early 'Lyman-Werner' background (LWB) at high redshift, prior to the epoch of reionization. Because of the long mean…Mark Dijkstra, Zoltan Haiman, Andrei Mesinger et al.·Oct 1, 2008SaveLearn
Spectroscopic Confirmation of Two Massive Red-Sequence-Selected Galaxy Clusters at z ~ 1.2 in the SpARCS-North Cluster SurveyThe Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a deep z'-band imaging survey covering the Spitzer SWIRE Legacy fields designed to create the first large…Adam Muzzin, Gillian Wilson, H. K. C. Yee et al.·Oct 1, 2008SaveLearn
Deconstructing Baryon Acoustic Oscillations: A Comparison of MethodsThe Baryon Acoustic Oscillations (BAOs) or baryon wiggles which are present in the galaxy power spectrum at scales 100-150Mpc/h are powerful features with which to constrain cosmology. The potential…Anais Rassat, Adam Amara, Luca Amendola et al.·Oct 1, 2008SaveLearn
Halo Mass Functions in Early Dark Energy CosmologiesWe examine the linear density contrast at collapse time, δc for large-scale structure in dynamical dark energy cosmologies, including models with early dark energy. Contrary to previous results,…Matthew J. Francis, Geraint F. Lewis, Eric V. Linder·Sep 30, 2008SaveLearn
Microlensing variability in the gravitationally lensed quasar QSO 2237+0305 = the Einstein Cross. II. Energy profile of the accretion diskWe present the continuation of our long-term spectroscopic monitoring of the gravitationally lensed quasar QSO 2237+0305. We investigate the chromatic variations observed in the UV/optical continuum…A. Eigenbrod, F. Courbin, G. Meylan et al.·Sep 30, 2008SaveLearn
Tools for Dissecting Supernova Remnants Observed with Chandra: Methods and Application to the Galactic Remnant W49BWe introduce methods to quantify the X-ray morphologies of supernova remnants observed with the Chandra X-ray Telescope. These include a power-ratio technique to measure morphological asymmetries,…Laura A. Lopez, Enrico Ramirez-Ruiz, David A. Pooley et al.·Sep 30, 2008SaveLearn
Modeling the magnetic field in the protostellar source NGC 1333 IRAS 4AMagnetic fields are believed to play a crucial role in the process of star formation. We compare high-angular resolution observations of the submillimeter polarized emission of NGC 1333 IRAS 4A,…Jose Goncalves, Daniele Galli, Josep M. Girart·Sep 30, 2008SaveLearn
Galactic secondary positron flux at the EarthSecondary positrons are produced by spallation of cosmic rays within the interstellar gas. Measurements have been typically expressed in terms of the positron fraction, which exhibits an increase…T. Delahaye, F. Donato, N. Fornengo et al.·Sep 30, 2008SaveLearn
Hydrodynamical Velocity Fields in Planetary NebulaeBased on axi-symmetric hydrodynamical simulations and 3D reconstructions with Shape, we investigate the kinematic signatures of deviations from homologous ("Hubble-type") outflows in some…W. Steffen, G. Garcia-Segura, N. Koning·Sep 30, 2008SaveLearn
Coordinate Data and Stars Identification in Astrophysical CatalogsThe aim of our paper is to make high-precision positional stellar catalogs by compiling large astrophysical data bulk and large astrometrical surveys. The data reliability and uniqueness is the…Nuriya T. Ashimbaeva·Sep 30, 2008SaveLearn
New Relativistic Particle-In-Cell Simulation Studies of Prompt and Early Afterglows from GRBsNonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and microquasars commonly exhibit…K. -I. Nishikawa, J. Niemiec, H. Sol et al.·Sep 30, 2008SaveLearn
Upper Limits on the Masses of 105 Supermassive Black Holes from Hubble Space Telescope/Space Telescope Imaging Spectrograph Archival DataBased on the modeling of the central emission-line width measured over sub-arcsecond apertures with the Hubble Space Telescope, we present stringent upper bounds on the mass of the central…A. Beifiori, M. Sarzi, E. M. Corsini et al.·Sep 30, 2008SaveLearn
UHECR observations and lensing in the magnetic field of the Virgo clusterWe discuss how lensing by magnetic fields in galaxy clusters affects ultrahigh energy cosmic ray (UHECR) observations. As specific example, we use Virgo together with the cluster magnetic fields…K. Dolag, M. Kachelriess, D. V. Semikoz·Sep 30, 2008SaveLearn
Evidence for powerful AGN winds at high redshift: Dynamics of galactic outflows in radio galaxies during the "Quasar Era"AGN feedback now appears as an attractive mechanism to resolve some of the outstanding problems with the "standard" cosmological models, in particular those related to massive galaxies. To…N. P. H. Nesvadba, M. D. Lehnert, C. De Breuck et al.·Sep 30, 2008SaveLearn
The neutrino signal from protoneutron star accretion and black hole formationWe discuss the formation of stellar mass black holes via protoneutron star (PNS) collapse. In the absence of an earlier explosion, the PNS collapses to a black hole due to the continued mass…T. Fischer, S. C. Whitehouse, A. Mezzacappa et al.·Sep 30, 2008SaveLearn
Cosmology from very high energy γ-raysIn this work we study how the cosmological parameter, the Hubble constant H0, can be constrained by observation of very high energy (VHE) γ-rays at the TeV scale. The VHE γ-rays experience…Xiao-Jun Bi, Qiang Yuan·Sep 30, 2008SaveLearn
The Spine of the Cosmic WebWe present the SpineWeb framework for the topological analysis of the Cosmic Web and the identification of its walls, filaments and cluster nodes. Based on the watershed segmentation of the cosmic…Miguel A. Aragon-Calvo, Erwin Platen, Rien van de Weygaert et al.·Sep 30, 2008SaveLearn
Non-thermal radiation from molecular clouds illuminated by cosmic rays from nearby supernova remnantsMolecular clouds are expected to emit non-thermal radiation due to cosmic ray interactions in the dense magnetized gas. Such emission is amplified if a cloud is located close to an accelerator of…Stefano Gabici, Sabrina Casanova, Felix A. Aharonian·Sep 30, 2008SaveLearn
The effect of progenitor age and metallicity on luminosity and 56Ni yield in Type Ia supernovaeTimmes, Brown & Truran found that metallicity variations could theoretically account for a 25% variation in the mass of 56Ni synthesized in Type Ia supernovae (SNe Ia), and thus account for a large…D. A. Howell, M. Sullivan, E. F. Brown et al.·Sep 30, 2008SaveLearn