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Astrophysics papers — page 10

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The Environments of Active Galactic Nuclei within the zCOSMOS Density Field
The impact of environment on AGN activity up to z~1 is assessed by utilizing a mass-selected sample of galaxies from the 10k catalog of the zCOSMOS spectroscopic redshift survey. We identify 147 AGN…
J. D. Silverman, K. Kovac, C. Knobel et al.Dec 18, 2008
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Brane inflation revisited after WMAP five-year results
In this paper, we revisit brane inflation models with the WMAP five-year results. The WMAP five-year data favor a red-tilted power spectrum of primordial fluctuations at the level of two standard…
Yin-Zhe Ma, Xin ZhangDec 17, 2008
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The X-ray Jets of Active Galaxies
Jet physics is again flourishing as a result of Chandra's ability to resolve high-energy emission from the radio-emitting structures of active galaxies and separate it from the X-ray-emitting thermal…
D. M. WorrallDec 17, 2008
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The shape of primordial non-Gaussianity and the CMB bispectrum
We present a set of formalisms for comparing, evolving and constraining primordial non-Gaussian models through the CMB bispectrum. We describe improved methods for efficient computation of the full…
J. R. Fergusson, E. P. S. ShellardDec 17, 2008
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Fluctuations in the Ionizing Background During and After Helium Reionization
The radiation background above the ionization edge of HeII varies strongly during and after helium reionization, because the attenuation length of such photons is relatively short (<40 Mpc) and…
Steven FurlanettoDec 17, 2008
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A New Secular Instability of Eccentric Stellar Disks Around Supermassive Black Holes, with Application to the Galactic Center
We identify a new secular instability of eccentric stellar disks around supermassive black holes. We show that retrograde precession of the stellar orbits, due to the presence of a stellar cusp,…
Ann-Marie Madigan, Yuri Levin, Clovis HopmanDec 17, 2008
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Study of the Spectral and Temporal Characteristics of X-Ray Emission of the Gamma-Ray Binary LS 5039 with Suzaku
We report on the results from Suzaku broadband X-ray observations of the galactic binary source LS5039. The Suzaku data, which have continuous coverage of more than one orbital period, show strong…
T. Takahashi, T. Kishishita, Y. Uchiyama et al.Dec 17, 2008
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Evolution in the properties of Lyman-alpha emitters from redshifts z ~ 3 to z ~ 2
Context: Narrow-band surveys for Ly-alpha emitters (LAEs) is a powerful tool in detecting high, and very high, redshift galaxies. Even though samples are growing at redshifts z = 3 - 6, the nature of…
Kim K. Nilsson, Christian Tapken, Palle Moeller et al.Dec 17, 2008
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The updated spectral catalogue of INTEGRAL Gamma-Ray Bursts
We present a catalogue with the properties of all the bursts detected and localized by the IBIS instrument onboard the INTEGRAL satellite from November 2002 to September 2008. The sample is composed…
G. Vianello, D. Götz, S. MereghettiDec 17, 2008
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What did we learn from the extremely bright gamma ray bursts 990123 and 080319B?
The two brightest and so far the best studied gamma ray bursts (GRBs), 990123 and 080319B, were ordinary, highly collimated GRBs produced in a core collapse supernova explosion within a high-density…
Shlomo Dado, Arnon DarDec 17, 2008
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Ultra faint dwarfs: probing early cosmic star formation
We investigate the nature of the newly discovered Ultra Faint dwarf spheroidal galaxies (UF dSphs) in a general cosmological context simultaneously accounting for various ``classical`` dSphs and…
Stefania Salvadori, Andrea FerraraDec 17, 2008
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Clarifying the covariant formalism for the SZ effect due to relativistic non-thermal electrons
We derive the covariant formalism associated with the relativistic Sunyaev-Zel'dovich effect due to a non-thermal population of high energy electrons in clusters of galaxies. More precisely, we…
Celine Boehm, Julien LavalleDec 17, 2008
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Gamma Ray Bursts Cook Book II: Simulation
In Paper I we presented a detailed formulation of the relativistic shocks and synchrotron emission in the context of Gamma-Ray Burst (GRB) physics. To see how well this model reproduces the observed…
Houri ZiaeepourDec 17, 2008
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Gamma Ray Bursts Cook Book I: Formulation
Since the suggestion of relativistic shocks as the origin of gamma-ray bursts (GRBs) in early 90's, the mathematical formulation of this process has stayed at phenomenological level. One of the…
Houri ZiaeepourDec 17, 2008
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Shear dynamo problem: Quasilinear kinematic theory
Large-scale dynamo action due to turbulence in the presence of a linear shear flow is studied. Our treatment is quasilinear and kinematic but is non perturbative in the shear strength. We derive the…
S. Sridhar, Kandaswamy SubramanianDec 17, 2008
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How Interstellar Chemistry (and Astrochemistry More Generally) Became Useful
In 1986 Alex Dalgarno published a paper entitled "Is Interstellar Chemistry Useful?" By the middle 1970s, and perhaps even earlier, Alex had hoped that astronomical molecules would prove to: possess…
T. W. Hartquist, S. Van Loo, S. A. E. G. FalleDec 17, 2008
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WASP-12b: The hottest transiting planet yet discovered
We report on the discovery of WASP-12b, a new transiting extrasolar planet with R pl=1.79 0.09 RJ and M pl=1.41 0.1 MJ. The planet and host star properties were derived from…
L. Hebb, A. Collier-Cameron, B. Loeillet et al.Dec 17, 2008
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AGN jet physics from measurements of the frequency-dependent position of the VLBI radio core
Accurate measurement of the frequency-dependent shift of the self-absorbed radio core is required for multi-frequency analysis of VLBI data since absolute positional information is lost as a result…
Shane P. O'Sullivan, Denise C. GabuzdaDec 17, 2008
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New CO detections of lensed submillimeter galaxies in A2218: Probing molecular gas in the LIRG regime at high redshift
Context: Submillimeter galaxies (SMGs) are distant, dusty galaxies undergoing star formation at prodigious rates. Recently there has been major progress in understanding the nature of the bright SMGs…
K. K. Knudsen, R. Neri, J. -P. Kneib et al.Dec 17, 2008
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Probing ISM Magnetic Fields With SNRs
As supernova remnants expand, their shock waves are freezing in and compressing the magnetic field lines they encounter; consequently we can use supernova remnants as magnifying glasses for their…
Roland Kothes Jo-Anne BrownDec 17, 2008
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Two pairs of interacting EBs towards the LMC in the OGLE database
A single point source on the OGLE LMC database shows the characteristics of two superimposed eclipsing binaries (EBs). The two EBs happen to have periods very close to the 3:2 resonance. The…
Aviv OfirDec 17, 2008
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The shaping effect of collimated fast outflows in the Egg nebula
We present high angular resolution observations of the HC3N J=5--4 line from the Egg nebula, which is the archetype of protoplanetary nebulae. We find that the HC 3N emission in the…
Dinh-V-Trung, Jeremy LimDec 17, 2008
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Tracing the asymmetry in the envelope around the carbon star CIT 6
We present high angular resolution observations of HC3N J=5--4 line and 7 mm continumm emission from the extreme carbon star CIT 6. We find that the 7 mm continuum emission is unresolved and has a…
Dinh-V-Trung, Jeremy LimDec 17, 2008
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Effects of Magnetic Field Strength and Orientation on Molecular Cloud Formation
We present a set of numerical simulations addressing the effects of magnetic field strength and orientation on the flow-driven formation of molecular clouds. Fields perpendicular to the flows…
F. Heitsch, J. M. Stone, L. W. HartmannDec 17, 2008
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The formation of the black hole in the X-ray binary system V404 Cyg
Using new and archival radio data, we have measured the proper motion of the black hole X-ray binary V404 Cyg to be 9.2+/-0.3 mas/yr. Combined with the systemic radial velocity from the literature,…
J. C. A. Miller-Jones, P. G. Jonker, G. Nelemans et al.Dec 17, 2008
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