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Astrophysics papers — page 154

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The Kuiper Belt and Other Debris Disks
We discuss the current knowledge of the Solar system, focusing on bodies in the outer regions, on the information they provide concerning Solar system formation, and on the possible relationships…
David Jewitt, Amaya Moro-Martín, Pedro LacerdaAug 24, 2008
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Can optical afterglows be used to discriminate between Type I and Type II GRBs?
The precise localization of short/hard (Type I) gamma-ray bursts (GRBs) in recent years has answered many questions but raised even more. I present some results of a systematic study of the optical…
D. A. KannAug 24, 2008
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Chamaeleon
The dark clouds in the constellation of Chamaeleon have distances of 160-180 pc from the Sun and a total mass of ~5000 Msun. The three main clouds, Cha I, II, and III, have angular sizes of a few…
Kevin L. LuhmanAug 23, 2008
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High Angular Resolution Observations at 7-mm of the Core of the Quadrupolar HH 111/121 Outflow
We present sensitive, high angular resolution (0.''05) VLA continuum observations made at 7 mm of the core of the HH 111/121 quadrupolar outflow. We estimate that at this wavelength…
L. F. Rodriguez, J. M. Torrelles, G. Anglada et al.Aug 23, 2008
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Oblique Ion Two-Stream Instability in the Foot Region of a Collisionless Shock
Electrostatic behavior of a collisionless plasma in the foot region of high Mach number perpendicular shocks is investigated through the two-dimensional linear analysis and electrostatic…
Yutaka Ohira, Fumio TakaharaAug 23, 2008
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Nonlinear theory of resonant slow waves in anisotropic and dispersive plasmas
The solar corona is a typical example of a plasma with strongly anisotropic transport processes. The main dissipative mechanisms in the solar corona acting on slow magnetoacoustic waves are the…
Christopher Clack, Istvan BallaiAug 23, 2008
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An Extensive, Sensitive Search for SiO Masers in High- and Intermediate-Mass Star-Forming Regions
We present sensitive Very Large Array observations with an angular resolution of a few arcseconds of the J= 1 - 0 line of SiO in the v=1 and 2 vibrationally excited states toward a sample of 60…
Luis A. Zapata, Karl Menten, Mark Reid et al.Aug 23, 2008
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The Science of Galaxy Formation
Our knowledge of the Universe remains discovery-led: in the absence of adequate physics-based theory, interpretation of new results requires a scientific methodology. Commonly, scientific progress in…
Gerard GilmoreAug 23, 2008
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Searching for Narrow Emission Lines in X-ray Spectra: Computation and Methods
The detection and quantification of narrow emission lines in X-ray spectra is a challenging statistical task. The Poisson nature of the photon counts leads to local random fluctuations in the…
Taeyoung Park, David A. van Dyk, Aneta SiemiginowskaAug 23, 2008
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The W40 Cloud Complex
The W40 complex is a nearby site of recent massive star formation composed of a dense molecular cloud adjacent to an HII region that contains an embedded OB star cluster. The HII region is beginning…
Steven A. Rodney, Bo ReipurthAug 23, 2008
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Strong mass segregation around a massive black hole
We show that the mass-segregation solution for the steady state distribution of stars around a massive black hole (MBH) has two branches: the known weak segregation solution (Bahcall & Wolf 1977),…
Tal Alexander, Clovis HopmanAug 23, 2008
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Asteroseismology and the Solar-Stellar Connection
In March 2009, NASA will launch the Kepler satellite -- a mission designed to discover habitable Earth-like planets around distant Sun-like stars. The method that Kepler will use to detect distant…
Travis S. MetcalfeAug 22, 2008
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Relic density of neutrinos with primordial asymmetries
We study flavor oscillations in the early universe, assuming primordial neutrino-antineutrino asymmetries. Including collisions and pair processes in the kinetic equations, we not only estimate the…
Sergio Pastor, Teguayco Pinto, Georg RaffeltAug 22, 2008
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The star-formation history of K-selected galaxies
We have studied the uJy radio properties of K-selected galaxies detected in the Ultra-Deep Survey portion of UKIDSS using 610- and 1,400-MHz images from the VLA and GMRT. These deep radio mosaics,…
L. Dunne, R. J. Ivison, S. Maddox et al.Aug 22, 2008
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Complete Treatment of Galaxy Two-Point Statistics: Gravitational Lensing Effects and Redshift-Space Distortions
We present a coherent theoretical framework for computing gravitational lensing effects and redshift-space distortions in an inhomogeneous universe and investigate their impacts on galaxy two-point…
Jaiyul YooAug 22, 2008
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Crossing the Phantom Divide with Parameterized Post-Friedmann Dark Energy
Dark energy models with a single scalar field cannot cross the equation of state divide set by a cosmological constant. More general models that allow crossing require additional degrees of freedom…
Wenjuan Fang, Wayne Hu, Antony LewisAug 22, 2008
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The Evolution Of Carbon, Sulphur, and Titanium Isotopes from High-Redshift to the Local Universe
Recent observations of carbon, sulphur, and titanium isotopes at redshifts z~1 and in the local stellar disc and halo have opened a new window into the study of isotopic abundance patterns and the…
G. L. Hughes, B. K. Gibson, L. Carigi et al.Aug 22, 2008
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Heavy Coronal Ions in the Heliosphere: I. Global Distribution of Charge-states of C, N, O, Mg, Si and S
Aims: Investigate/Study de-charging of solar wind C, N, O, Mg, Si and S ions and assess fluxes of resulting ENA in the heliosphere. Methods: The model treats the heavy ions as test particles…
S. Grzedzielski, M. E. Wachowicz, M. Bzowski et al.Aug 22, 2008
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Monitoring Supergiant Fast X-ray Transients with Swift. III. Outbursts of the prototypical SFXTs IGR J17544-2619 and XTE J1739-302
IGR J17544-2619 and XTE J1739-302 are considered the prototypical sources of the new class of High Mass X-ray Binaries, the Supergiant Fast X-ray Transients (SFXTs).These sources were observed during…
L. Sidoli, P. Romano, V. Mangano et al.Aug 22, 2008
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The flip-side of galaxy formation: A combined model of Galaxy Formation and Cluster Heating
Only ~10% of baryons in the universe are in the form of stars, yet most models of luminous structure formation have concentrated on the properties of the luminous stellar matter. In this paper we…
Richard G. Bower, Ian G. McCarthy, Andrew J. BensonAug 22, 2008
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Tkachenko waves, glitches and precession in neutron star
Here I discuss possible relations between free precession of neutron stars, Tkachenko waves inside them and glitches. I note that the proposed precession period of the isolated neutron star RX…
S. B. PopovAug 22, 2008
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Perturbation of Nuclear Decay Rates During the Solar Flare of 13 December 2006
Recently, Jenkins, et al. have reported the detection of correlations between fluctuations in nuclear decay rates and Earth-Sun distance, which suggest that nuclear decay rates can be affected by…
Jere H. Jenkins, Ephraim FischbachAug 22, 2008
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A Sample of Very Young Field L Dwarfs and Implications for the Brown Dwarf "Lithium Test" at Early Ages
Using a large sample of optical spectra of late-type dwarfs, we identify a subset of late-M through L field dwarfs that, because of the presence of low-gravity features in their spectra, are believed…
J. Davy Kirkpatrick, Kelle L. Cruz, Travis S. Barman et al.Aug 22, 2008
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Suzaku Observations of Four Heavily Absorbed HMXBs
We report on Suzaku observations of four unidentified sources from the INTEGRAL and Swift BAT Galactic plane surveys. All the sources have a large neutral hydrogen column density and are likely…
D. C. Morris, R. K. Smith, C. B. Markwardt et al.Aug 22, 2008
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Direct calculation of the radiative efficiency of an accretion disk around a black hole
Numerical simulation of magnetohydrodynamic (MHD) turbulence makes it possible to study accretion dynamics in detail. However, special effort is required to connect inflow dynamics (dependent largely…
Scott C. Noble, Julian H. Krolik, John F. HawleyAug 22, 2008
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