The Canis Major Star Forming RegionThe shape of the main arc formed by the Canis Major clouds has been suggested to result from a supernova explosion possibly triggering the recent star formation activity. The presence of dozens of OB…Jane Gregorio-Hetem·Aug 28, 2008SaveLearn
Rotation and surface abundance peculiarities in A-type starsIn an attempt of clarifying the connection between the photospheric abundance anomalies and the stellar rotation as well as of exploring the nature of "normal A" stars, the abundances of…Yoichi Takeda, Inwoo Han, Dong-Il Kang et al.·Aug 28, 2008SaveLearn
Curvature Effect of a Non-Power-Law Spectrum and Spectral Evolution of GRB X-Ray TailsThe apparent spectral evolution observed in the steep decay phase of many GRB early afterglows raises a great concern of the high-latitude "curvature effect" interpretation of this phase.…Bin-Bin Zhang, Bing Zhang, En-Wei Liang et al.·Aug 27, 2008SaveLearn
No large-angle correlations on the non-Galactic microwave skyWe investigate the angular two-point correlation function of temperature in the WMAP maps. Updating and extending earlier results, we confirm the lack of correlations outside the Galaxy on angular…Craig J. Copi, Dragan Huterer, Dominik J. Schwarz et al.·Aug 27, 2008SaveLearn
Effect of Helium Sedimentation on X-ray Measurements of Galaxy ClustersThe uniformity of the helium-to-hydrogen abundance ratio in X-ray emitting intracluster medium (ICM) is one of the commonly adopted assumptions in X-ray analyses of galaxy clusters and cosmological…Fang Peng, Daisuke Nagai·Aug 27, 2008SaveLearn
High-(Energy)-Lights -- The Very High Energy Gamma-Ray SkyThe high-lights of ground-based very-high-energy (VHE, E>100 GeV) gamma-ray astronomy are reviewed. The summary covers both Galactic and extra-galactic sources. A total of at least 70 sources are…D. Horns·Aug 27, 2008SaveLearn
New Positron Spectral Features from Supersymmetric Dark Matter - a Way to Explain the PAMELA Data?The space-borne antimatter experiment PAMELA has recently reported a surprising rise in the positron to electron ratio at high energies. It has also recently been found that electromagnetic radiative…Lars Bergstrom, Torsten Bringmann, Joakim Edsjo·Aug 27, 2008SaveLearn
X-ray clusters of galaxies in conformal gravityWe run adiabatic N-body/hydrodynamical simulations of isolated self-gravitating gas clouds to test whether conformal gravity, an alternative theory to General Relativity, is able to explain the…Antonaldo Diaferio, Luisa Ostorero·Aug 27, 2008SaveLearn
Constraints on the star formation histories of galaxies from z~1 to z~0We present a new method to estimate the average star formation rate per unit stellar mass (SSFR) of a stacked population of galaxies. We combine the spectra of 600-1000 galaxies with similar stellar…Yan-Mei Chen, Vivienne Wild, Guinevere Kauffmann et al.·Aug 27, 2008SaveLearn
A Roche Model for Uniformly Rotating RingsA Roche model for describing uniformly rotating rings is presented and the results are compared with numerical solutions to the full problem for polytropic rings. In the thin ring limit, the surfaces…Stefan Horatschek, David Petroff·Aug 27, 2008SaveLearn
Numerical Models of Travel-Time Inhomogeneities in SunspotsWe investigate the direct contribution of strong, sunspot-like magnetic fields to helioseismic wave travel-time shifts via two numerical forward models, a 3D ideal MHD solver and MHD ray theory. The…H. Moradi, S. M. Hanasoge, P. S. Cally·Aug 27, 2008SaveLearn
Difficulties of Preserving the Leap SecondWe examine the possibility to extend leap second extrapolation for a near future based on some periodic terms in the Earth's rotation changes. The IERS data, covering the interval from 1962.15 to…S. Segan, B. Surlan, S. Vidojevic·Aug 27, 2008SaveLearn
Radiation from relativistic jetsNonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems…K. -I. Nishikawa, Y. Mizuno, P. Hardee et al.·Aug 27, 2008SaveLearn
Toward precise constraints on growth of massive black holesGrowth of massive black holes (MBHs) in galactic centers comes mainly from gas accretion during their QSO/AGN phases. In this paper we apply an extended Soltan argument, connecting the local MBH mass…Qingjuan Yu, Youjun Lu·Aug 27, 2008SaveLearn
Formation of a Quasar Host Galaxy through a Wet Merger 1.4 Billion Years after the Big BangWe present high-resolution Very Large Array imaging of the molecular gas in the host galaxy of the high redshift quasar BRI 1335-0417 (z=4.41). Our CO(2-1) observations have a linear resolution of…Dominik A. Riechers, Fabian Walter, Christopher L. Carilli et al.·Aug 27, 2008SaveLearn
A common mass scale for satellite galaxies of the Milky WayThe Milky Way has at least twenty-three known satellite galaxies that shine with luminosities ranging from about a thousand to a billion times that of the Sun. Half of these galaxies were discovered…Louis E. Strigari, James S. Bullock, Manoj Kaplinghat et al.·Aug 27, 2008SaveLearn
Using Spatial Distributions to Constrain Progenitors of Supernovae and Gamma Ray BurstsWe carry out a comprehensive theoretical examination of the relationship between the spatial distribution of optical transients and the properties of their progenitor stars. By constructing analytic…Cody Raskin, Evan Scannapieco, James Rhoads et al.·Aug 27, 2008SaveLearn
Thermal Flipping of Interstellar GrainsIn interstellar dust grains, internal processes dissipate rotational kinetic energy. The dissipation is accompanied by thermal fluctuations, which transfer energy from the vibrational modes to…Joseph C. Weingartner·Aug 27, 2008SaveLearn
On The Origins Of Eccentric Close-in PlanetsStrong tidal interaction with the central star can circularize the orbits of close-in planets. With the standard tidal quality factor Q of our solar system, estimated circularization times for…Soko Matsumura, Genya Takeda, Fred Rasio·Aug 27, 2008SaveLearn
Stellar Evolution in the Early UniverseMassive stars played a key role in the early evolution of the Universe. They formed with the first halos and started the re-ionisation. It is therefore very important to understand their evolution.…R. Hirschi, U. Frischknecht, F. -K. Thielemann et al.·Aug 27, 2008SaveLearn
Imaging galactic diffuse gas: Bright, turbulent CO surrounding the line of sight to NRAO150To understand the environment and extended structure of the host galactic gas whose molecular absorption line chemistry, we previously observed along the microscopic line of sight to the…Jérôme Pety, Robert Lucas, Harvey S. Liszt·Aug 27, 2008SaveLearn
An X-ray photometry system I: Chandra ACISWe present a system of X-ray photometry for the Chandra satellite. X-ray photometry can be a powerful tool to obtain flux estimates, hardness ratios, and colors unbiased by assumptions about spectral…H. -J. Grimm, J. McDowell, G. Fabbiano et al.·Aug 27, 2008SaveLearn
Nulling interferometry: performance comparison between space and ground-based sites for exozodiacal disc detectionCharacterising the circumstellar dust around nearby main sequence stars is a necessary step in understanding the planetary formation process and is crucial for future life-finding space missions such…D. Defrère, O. Absil, V. Coudé du Foresto et al.·Aug 27, 2008SaveLearn
Dynamical suppression of non-adiabatic modesRecent analyses of the WMAP 5-year data constrain possible non-adiabatic contributions to the initial conditions of CMB anisotropies. Depending upon the early dynamics of the plasma, the amplitude of…Massimo Giovannini·Aug 27, 2008SaveLearn
AGILE detection of variable gamma-ray activity from the blazar S5 0716+714 during September-October 2007We report the gamma-ray activity from the Intermediate BL Lac S5 0716+714 during 2007 September-October observations by the AGILE satellite, coincident with a period of intense optical activity of…F. D'Ammando, A. W. Chen, M. Villata et al.·Aug 27, 2008SaveLearn