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Astrophysics papers — page 67

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Explosive Nucleosynthesis of Weak r-Process Elements in Extremely Metal-Poor Core-Collapse Supernovae
There have been attempts to fit the abundance patterns of extremely metal-poor stars with supernova nucleosynthesis models for the lighter elements than Zn. On the other hand, observations have…
N. Izutani, H. Umeda, N. TominagaOct 31, 2008
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Regularities in the frequency spacings of Delta Scuti stars and the s-f Diagram
Statistical analyses of several Delta Scuti stars (FG Vir, 44 Tau, BL Cam and others) show that the photometrically observed frequencies cluster around the frequencies of the radial modes over many…
M. Breger, P. Lenz, A. A. PamyatnykhOct 31, 2008
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Radiation processes around accreting black holes
Accreting sources such as AGN, X-ray binaries or gamma-ray bursts are known to be strong, high energy emitters. The hard emission is though to originate from plasmas of thermal and/or non-thermal…
R. Belmont, J. Malzac, A. MarcowithOct 31, 2008
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Simulating acceleration and radiation processes in X-ray binaries
The high energy emission of microquasars is thought to originate from high energy particles. Depending on the spectral state, the distribution of these particles can be thermal with a high…
R. Belmont, J. Malzac, A. MarcowithOct 31, 2008
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Chemical Diversity in High-Mass Star Formation
Massive star formation exhibits an extremely rich chemistry. However, not much evolutionary details are known yet, especially at high spatial resolution. Therefore, we synthesize previously published…
H. Beuther, Q. Zhang, E. A. Bergin et al.Oct 31, 2008
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Suzaku observations of metallicity distribution in the intracluster medium of the NGC 5044 group
The metallicity distribution in the intracluster medium of the NGC 5044 group was studied up to 0.3 r180 using the XIS instrument on board the Suzaku satellite. Abundances of O, Mg, Si, S, and Fe…
Madoka Komiyama, Kosuke Sato, Ryo Nagino et al.Oct 31, 2008
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Galaxy Interactions, Star Formation History, and Bulgeless Galaxies
Hierarchical Lambda CDM models provide a successful paradigm for the growth of dark matter on large scales, but they face important challenges in predicting how the baryonic components of galaxies…
Shardha JogeeOct 31, 2008
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Intergalactic dust and its photoelectric heating
We have examined the dust photoelectric heating in the intergalactic medium (IGM). The heating rate in a typical radiation field of the IGM is represented by Γ pe = 1.2×10-34 erg…
Akio K. Inoue, Hideyuki KamayaOct 31, 2008
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Science with UT's Dichroic-Mirror Camera (DMC), 15-band simultaneous imager
We introduce the Dichroic-Mirror Camera (DMC), an instrument developed at the University of Tokyo which is capable of performing simultaneous imaging in fifteen bands. The main feature of the DMC is…
Hanindyo Kuncarayakti, Mamoru Doi, Hakim L. Malasan et al.Oct 31, 2008
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Dynamics of Galactic Disks and Mergers at z~1.6: Spatially Resolved Spectroscopy with Keck Laser Guide Star Adaptive Optics
We present 0.2" resolution near-infrared integral field spectroscopy of H-alpha emission from six star forming galaxies at z~1.6 (look-back time of ~9.6 Gyr). These observations were obtained…
Shelley A. Wright, James E. Larkin, David R. Law et al.Oct 31, 2008
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Cosmic transparency: A test with the baryon acoustic feature and type Ia supernovae
Conservation of the phase-space density of photons plus Lorentz invariance requires that the cosmological luminosity distance be larger than the angular diameter distance by a factor of (1+z)2,…
Surhud More, Jo Bovy, David W. HoggOct 30, 2008
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Jet-BLR connection in the radio galaxy 3C 390.3
Variations of the optical continuum emission in the radio galaxy 3C 390.3 are compared to the properties of radio emission from the compact, sub-parsec-scale jet in this object. We showed that very…
T. G. Arshakian, J. Leon-Tavares, A. P. Lobanov et al.Oct 30, 2008
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Linear dynamics of weakly viscous accretion disks: A disk analog of Tollmien-Schlichting waves
This paper discusses new perspectives and approaches to the problem of disk dynamics where, in this study, we focus on the effects of viscous instabilities influenced by boundary effects. The…
O. M. Umurhan, G. ShavivOct 30, 2008
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Discovery of molecular shells associated with supernova remnants. (II) Kesteven 75
The young composite supernova remnant (SNR) Kesteven 75, with a pulsar wind nebula at its center, has an unusual morphology with a bright southern half-shell structure in multiwavelengths. The…
Yang Su, Yang Chen, Ji Yang et al.Oct 30, 2008
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Solar system tests do not rule out 1/R gravity
We argue that Solar system tests do not rule out 1/R gravity at least due to the reason addressed in Phys. Rev. D 74 (2006) 121501 [astro-ph/0610483] (ref. [1]) and subsequent published papers. Ref.…
Qasem ExirifardOct 30, 2008
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Cosmological Perturbations in Models of Coupled Dark Energy
Models in which dark energy interacts with dark matter have been proposed in the literature to help explain why dark energy should only come to dominate in recent times. In this paper, we present a…
Sirichai ChongchitnanOct 30, 2008
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The PAMELA Positron Excess from Annihilations into a Light Boson
Recently published results from the PAMELA experiment have shown conclusive evidence for an excess of positrons at high (~ 10 - 100 GeV) energies, confirming earlier indications from HEAT and AMS-01.…
Ilias Cholis, Douglas P. Finkbeiner, Lisa Goodenough et al.Oct 30, 2008
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Resolution of the Distance Ambiguity for Galactic HII Regions
We resolve the kinematic distance ambiguity for 266 inner Galaxy HII regions out of a sample of 291 using existing HI and 13CO sky surveys. Our sample contains all HII regions with measured radio…
L. D. Anderson, T. M. BaniaOct 30, 2008
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A High Precision, Optical Polarimeter to Measure Inclinations of High Mass X-Ray Binaries
We present commissioning data for the POLISH instrument obtained on the Hale 5-m telescope. The goal of this high precision polarimeter is to constrain orbital inclination of high mass X-ray binaries…
Sloane J. Wiktorowicz, Keith MatthewsOct 30, 2008
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Impacts of WIMP dark matter upon stellar evolution: main-sequence stars
The presence of large amounts of WIMP dark matter in stellar cores has been shown to have significant effects upon models of stellar evolution. We present a series of detailed grids of…
Pat Scott, Malcolm Fairbairn, Joakim EdsjöOct 30, 2008
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A spectroscopic survey of dwarf galaxies in the Coma Cluster: Stellar populations, environment and downsizing
We investigate the stellar populations in a sample of 89 faint (M*+2 to M*+4) red galaxies in the Coma cluster, using high S/N spectroscopy from the MMT. Our sample is drawn from two 1-degree fields,…
Russell J. Smith, John R. Lucey, Michael J. Hudson et al.Oct 30, 2008
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Fluorescent excitation of Balmer lines in gaseous nebulae: case D
(abridged) Non-ionizing stellar continua are a source of photons for continuum pumping in the hydrogen Lyman transitions. In the environments where these transitions are optically thick, deexcitation…
V. Luridiana, S. Simon-Diaz, M. Cervino et al.Oct 30, 2008
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TeV variability in blazars: how fast can it be?
Recent Cerenkov observations of the two BL Lac objects PKS 2155-304 and Mkn 501 revealed TeV flux variability by a factor ~2 in just 3-5 minutes. Even accounting for the effects of relativistic…
G. Ghisellini, F. Tavecchio, G. Bodo et al.Oct 30, 2008
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LISA detection of massive black hole binaries: imprint of seed populations and of exterme recoils
All the physical processes involved in the formation, merging, and accretion history of massive black holes along the hierarchical build--up of cosmic structures are likely to leave an imprint on the…
A. Sesana, M. Volonteri, F. HaardtOct 30, 2008
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Distance determination to 12 Type II Supernovae using the Expanding Photosphere Method
We used early time photometry and spectroscopy of 12 Type II plateau Supernovae (SNe IIP) to derive their distances using the Expanding Photosphere Method (EPM). We performed this study using two…
Matias I. JonesOct 30, 2008
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