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Astrophysics papers — page 161

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A growing dynamo from a saturated Roberts flow dynamo
Using direct simulations, weakly nonlinear theory and nonlinear mean-field theory, it is shown that the quenched velocity field of a saturated nonlinear dynamo can itself act as a kinematic dynamo.…
Andreas Tilgner, Axel BrandenburgAug 15, 2008
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Comments on Scalar-Tensor Representation of f(R) Theories
We propose a scalar-tensor representation of f(R) theories with use of conformal transformations. In this representation, the model takes the form of the Brans-Dicke model with a potential function…
Yousef BisabrAug 15, 2008
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Is there a redshift cutoff for submillimetre galaxies?
We present new optical and infrared photometry for a statistically complete sample of seven 1.1 mm selected sources with accurate Submillimetre Array coordinates. We determine photometric redshifts…
G. Raymond, S. A. Eales, S. Dye et al.Aug 15, 2008
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Correlated Multi-Waveband Variability in the Blazar 3C~279 from 1996 to 2007
We present the results of extensive multi-waveband monitoring of the blazar 3C~279 between 1996 and 2007 at X-ray energies (2-10 keV), optical R band, and 14.5 GHz, as well as imaging with the Very…
R. Chatterjee, S. G. Jorstad, A. P. Marscher et al.Aug 15, 2008
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Interferometric imaging of the high-redshift radio galaxy, 4C60.07: An SMA, Spitzer and VLA study reveals a binary AGN/starburst
High-resolution submm imaging of the HzRG, 4C60.07, at z=3.8, has revealed two dusty components. Spitzer imaging shows that one of these components (B) is coincident with an extremely red AGN, offset…
R. J. Ivison, G. E. Morrison, A. D. Biggs et al.Aug 15, 2008
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Interstellar Weather Vanes: GLIMPSE Mid-Infrared Stellar-Wind Bowshocks in M17 and RCW49
We report the discovery of six infrared stellar-wind bowshocks in the Galactic massive star formation regions M17 and RCW49 from Spitzer GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey…
Matthew S. Povich, Robert A. Benjamin, Barbara A. Whitney et al.Aug 15, 2008
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NTT follow-up observations of star cluster candidates from the FSR catalogue
We are conducting a large program to classify newly discovered Milky Way star cluster candidates from the list of Froebrich, Scholz & Raftery (2007). Here we present deep NIR follow-up observations…
D. Froebrich, H. Meusinger, A. ScholzAug 15, 2008
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Estimating stellar rotation from starspot detection during planetary transits
A new method for determining the stellar rotation period is proposed here, based on the detection of starspots during transits of an extra-solar planet orbiting its host star. As the planet eclipses…
Adriana Silva-ValioAug 15, 2008
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Post Common Envelope Binaries from SDSS - III. Seven new orbital periods
We present follow-up spectroscopy and photometry of 11 post common envelope binary (PCEB) candidates identified from multiple Sloan Digital Sky Survey (SDSS) spectroscopy in an earlier paper. Radial…
A. Rebassa-Mansergas, B. T. Gaensicke, M. R. Schreiber et al.Aug 15, 2008
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Misalignment of the microquasar V4641 Sgr (SAX J1819.3--2525)
In the microquasar V4641 Sgr the spin of the black hole is thought to be misaligned with the binary orbital axis. The accretion disc aligns with the black hole spin by the Lense-Thirring effect near…
Rebecca G. Martin, Rubens C. Reis, J. E. PringleAug 15, 2008
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A multi-zone model for simulating the high energy variability of TeV blazars
We present a time-dependent multi-zone code for simulating the variability of Synchrotron-Self Compton (SSC) sources. The code adopts a multi-zone pipe geometry for the emission region, appropriate…
Philip B. Graff, Markos Georganopoulos, Eric S. Perlman et al.Aug 15, 2008
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N/O-trends in Late-Type Galaxies: AGB-stars, IMFs, Abundance Gradients and the Origin of Nitrogen
Models of galactic chemical evolution (CEMs) show that the shape of the stellar initial mass function (IMF) and other assumptions regarding star formation affect the resultant abundance gradients in…
Lars MattssonAug 15, 2008
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The lack of carbon stars in the Galactic bulge
In order to explain the lack of carbon stars in the Galactic bulge, we have made a detailed study of thermal pulse - asymptotic giant branch stars by using a population synthesis code. The effects of…
Zhu Chunhua, Lv Guoliang, Wang Zhaojun et al.Aug 15, 2008
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The main sequence from F to K stars of the solar neighbourhood in SDSS colours
For an understanding of Galactic stellar populations in the SDSS filter system well defined stellar samples are needed. The nearby stars provide a complete stellar sample representative for the thin…
A. Just, H. JahreissAug 15, 2008
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The Compact Structure of Radio-Loud Broad Absorption Line Quasars
We present the results of EVN+MERLIN VLBI polarization observations of 8 Broad Absorption Line (BAL) quasars at 1.6 GHz, including 4 LoBALs and 4 HiBALs with either steep or flat spectra on VLA…
Y. Liu, D. R. Jiang, T. G. Wang et al.Aug 15, 2008
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Are dumbbell brightest cluster members signposts to galaxy cluster activity?
We assemble a sample of galaxy clusters whose brightest members are dumbbell galaxies and compare them with a control sample in order to investigate if they are the result of recent mergers. We show…
K. A. PimbbletAug 15, 2008
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Self-Similar Polytropic Champagne Flows in H II Regions
We explore large-scale hydrodynamics of H II regions for various self-similar shock flows of a polytropic gas cloud under self-gravity and with quasi-spherical symmetry. We formulate cloud dynamics…
Ren-Yu Hu, Yu-Qing LouAug 15, 2008
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Limits of Binaries That Can Be Characterized by Gravitational Microlensing
Due to the high efficiency of planet detections, current microlensing planet searches focus on high-magnification events. High-magnification events are sensitive to remote binary companions as well…
Doeon Kim, Yoon-Hyun Ryu, Byeong-Gon Park et al.Aug 15, 2008
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Constraining Gravitational and Cosmological Parameters with Astrophysical Data
We use astrophysical data to shed light on fundamental physics by constraining parametrized theoretical cosmological and gravitational models. Gravitational parameters are those constants that…
Yi MaoAug 15, 2008
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Gauging the cosmic microwave background
We provide a new derivation of the anisotropies of the cosmic microwave background (CMB), and find an exact expression that can be readily expanded perturbatively. Close attention is paid to gauge…
J. P. Zibin, Douglas ScottAug 14, 2008
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Symmetries in collective neutrino oscillations
We discuss the relationship between a symmetry in the neutrino flavour evolution equations and neutrino flavour oscillations in the collective precession mode. This collective precession mode can…
Huaiyu Duan, George M. Fuller, Yong-Zhong QianAug 14, 2008
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Shear viscosity in neutron star cores
We calculate the shear viscosity η= ηeμ+ηn in a neutron star core composed of nucleons, electrons and muons (ηeμ being the electron-muon viscosity, mediated by collisions of electrons…
P. S. Shternin, D. G. YakovlevAug 14, 2008
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An Iterative Method for Constructing Equilibrium Phase Models of Stellar Systems
We present a new method for constructing equilibrium phase models for stellar systems, which we call the iterative method. It relies on constrained, or guided evolution, so that the equilibrium…
S. A. Rodionov, E. Athanassoula, N. Ya SotnikovaAug 14, 2008
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First Cosmological Constraints on Dark Energy from the Radial Baryon Acoustic Scale
We present cosmological constraints arising from the first measurement of the radial (line-of-sight) baryon acoustic oscillations (BAO) scale in the large scale structure traced by the galaxy…
Enrique Gaztanaga, Ramon Miquel, Eusebio SanchezAug 14, 2008
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Does The Addition of a Duration Improve the Liso - Epeak Relation For Gamma-Ray Bursts?
Firmani et al. proposed a new Gamma Ray Burst (GRB) luminosity relation that showed a significant improvement over the Liso-Epeak relation. The new proposed relation simply modifies the Epeak…
Andrew C. Collazzi, Bradley E. SchaeferAug 14, 2008
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