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Astrophysics papers — page 113

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Kinematical & Chemical Characteristics of the Thin and Thick Disks
I discuss how the chemical abundance distributions, kinematics and age distributions of stars in the thin and thick disks of the Galaxy can be used to decipher the merger history of the Milky Way, a…
Rosemary F. G. WyseSep 26, 2008
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Estimating the Parameters of Sgr A*'s Accretion Flow Via Millimeter VLBI
Recent millimeter-VLBI observations of Sagittarius A* (Sgr A*) have, for the first time, directly probed distances comparable to the horizon scale of a black hole. This provides unprecedented access…
Avery E. Broderick, Vincent L. Fish, Sheperd S. Doeleman et al.Sep 25, 2008
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Using Millimeter VLBI to Constrain RIAF Models of Sagittarius A*
The recent detection of Sagittarius A* at lambda = 1.3 mm on a baseline from Hawaii to Arizona demonstrates that millimeter wavelength very long baseline interferometry (VLBI) can now spatially…
Vincent L. Fish, Avery E. Broderick, Sheperd S. Doeleman et al.Sep 25, 2008
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Towards accurate modelling of the ISW effect, the non-linear contribution
In a universe with a cosmological constant, the large-scale gravitational potential varies in time and this is, in principle, observable. Using an N-body simulation of a ΛCDM universe, we show that…
Yan-Chuan Cai, Shaun Cole, Adrian Jenkins et al.Sep 25, 2008
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The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
The stellar masses, mean ages, metallicities, and star formation histories of galaxies are now commonly estimated via stellar population synthesis (SPS) techniques. SPS relies on stellar evolution…
Charlie Conroy, James E. Gunn, Martin WhiteSep 25, 2008
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High Redshift Galaxy Populations and their Descendants
We study model predictions for three high-redshift galaxy populations: Lyman break galaxies at z~3 (LBGs), optically selected star-forming galaxies at z~2 (BXs), and distant red galaxies at z~2…
Qi Guo, Simon D. M. WhiteSep 25, 2008
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Hilltop Quintessence
We examine hilltop quintessence models, in which the scalar field is rolling near a local maximum in the potential, and w is close to -1. We first derive a general equation for the evolution of the…
Sourish Dutta, Robert J. ScherrerSep 25, 2008
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Early Universe cosmology in the light of the mirror dark matter interpretation of the DAMA/Libra signal
Mirror dark matter provides a simple framework for which to explain the DAMA/Libra annual modulation signal consistently with the null results of the other direct detection experiments. The simplest…
Paolo Ciarcelluti, Robert FootSep 25, 2008
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Depth estimation of the Large and Small Magellanic Clouds
We used the red clump stars from the photometric data of the Optical Gravitational Lensing Experiment(OGLE II) survey and the Magellanic Cloud Photometric Survey (MCPS) for both the Clouds to…
Smitha Subramanian, Annapurni SubramaniamSep 25, 2008
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Near-Infrared Studies of V1280 Sco (Nova Scorpii 2007)
We present spectroscopic and photometric results of Nova V1280 Sco which was discovered in outburst in early 2007 February. The large number of spectra obtained of the object leads to one of the most…
Ramkrishna Das, Dipankar Banerjee, Nagarhalli Ashok et al.Sep 25, 2008
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Discovery of Molecular Shells Associated with Supernova Remnants. I. Kesteven 69
Supernova remnant (SNR) Kes 69 is morphologically characterized by brightened radio, infrared, and X-ray emission on the southeastern rim, with the 1720 MHz OH masers detected in the northeastern and…
Xin Zhou, Yang Chen, Yang Su et al.Sep 25, 2008
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Constraining the LRG Halo Occupation Distribution using Counts-in-Cylinders
The low number density of the Sloan Digital Sky Survey (SDSS) Luminous Red Galaxies (LRGs) suggests that LRGs occupying the same dark matter halo can be separated from pairs occupying distinct dark…
Beth A. Reid, David N. SpergelSep 25, 2008
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Molecular cloud chemistry and the importance of dielectronic recombination
Dielectronic recombination (DR) of singly charged ions is a reaction pathway that is commonly neglected in chemical models of molecular clouds. In this study we include state-of-the-art DR data for…
P. Bryans, H. Kreckel, E. Roueff et al.Sep 25, 2008
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SIMP: A Near-Infrared Proper Motion Survey
SIMP is a proper motion (PM) survey made with the Observatoire du Mont Megantic (OMM) wide-field near-infrared camera CPAPIR at the CTIO 1.5 m and OMM 1.6 m telescopes. The SIMP observations were…
Etienne Artigau, David Lafreniere, Rene Doyon et al.Sep 25, 2008
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The ionizing background at the end of overlap
One of the most sought-after signatures of reionization is a rapid increase in the ionizing background (usually measured through the Lyman-alpha optical depth toward distant quasars). Conventional…
Steven Furlanetto, Andrei MesingerSep 25, 2008
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On surface brightness fluctuations: probabilistic and statistical bases I: Stellar population and theoretical SBF
This work aims to provide a theoretical formulation of Surface Brightness Fluctuations (SBF) in the framework of probabilistic synthesis models, and to distinguish between the different distributions…
M. Cervino, V. Luridiana, L. JametSep 25, 2008
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Comparison of High-degree Solar Acoustic Frequencies and Asymmetry between Velocity and Intensity Data
Using the local helioseismic technique of ring diagram we analyze the frequencies of high--degree f- and p-modes derived from both velocity and continuum intensity data observed by MDI. Fitting the…
S. C. Tripathy, H. M. Antia, Kiran Jain et al.Sep 25, 2008
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Star-Planet Interactions
Much effort has been invested in recent years, both observationally and theoretically, to understand the interacting processes taking place in planetary systems consisting of a hot Jupiter orbiting…
Evgenya Shkolnik, Suzanne Aigrain, Steven Cranmer et al.Sep 25, 2008
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Discovery of A Very Bright, Strongly-Lensed z=2 Galaxy in the SDSS DR5
We report on the discovery of a very bright z = 2.00 star-forming galaxy that is strongly lensed by a foreground z=0.422 luminous red galaxy (LRG). This system was found in a systematic search for…
Huan Lin, Elizabeth Buckley-Geer, Sahar S. Allam et al.Sep 25, 2008
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Deep Mixing and Metallicity: Carbon Depletion in Globular Cluster Giants
We present the results of an observational study of the efficiency of deep mixing in globular cluster red giants as a function of stellar metallicity. We determine [C/Fe] abundances based on…
Sarah L. Martell, Graeme H. Smith, Michael M. BrileySep 25, 2008
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Blue spectral inflation
We reconsider the nonlinear second order Abel equation of Stewart and Lyth, which follows from a nonlinear second order slow-roll approximation. We find a new eigenvalue spectrum in the blue regime.…
Franz E. Schunck, Eckehard W. MielkeSep 25, 2008
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Trumpler 20 - an old and rich open cluster
We show that the open cluster Trumpler 20, contrary to the earlier findings, is actually an old Galactic open cluster. New CCD photometry and high-resolution spectroscopy are used to derive the main…
I. Platais, C. Melo, J. P. Fulbright et al.Sep 25, 2008
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Two-component galaxies with flat rotation curve
Dynamical properties of two-component galaxy models whose stellar density distribution is described by a gamma-model while the total density distribution has a pure r(-2) profile, are presented. The…
Luca Ciotti, Lucia Morganti, Tim de ZeeuwSep 25, 2008
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Hydrodynamic Processes in Young Binary Systems as a Source of Cyclic Variations of Circumstellar Extinction
Hydrodynamic models of a young binary system accreting matter from the remnants of a protostellar cloud have been calculated by the SPH method. It is shown that periodic variations in column density…
N. Ya. Sotnikova, V. P. GrininSep 25, 2008
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Investigating the flyby scenario for the HD 141569 system
HD 141569, a triple star system, has been intensively observed and studied for its massive debris disk. It was rather regarded as a gravitationally bound triple system but recent measurements of the…
Rémy Reche, Hervé Beust, J. -C. AugereauSep 25, 2008
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