Showing 2004 · astro-phShow all

99 papers · 2 filters

astro-ph2004

Densification of the International Celestial Reference Frame: Results of EVN Observations

P. Charlot, A. L. Fey, C. S. Jacobs +3

The current realization of the International Celestial Reference Frame (ICRF) comprises a total of 717 extragalactic radio sources distributed over the entire sky. An observing pro…

astro-ph2004★ 19 cited

Gamma-Ray Spectral State Transitions of GRO J1719-24

J. C. Ling, Wm. A. Wheaton

We report BATSE earth-occultation observations of the long-term soft gamma-ray (30 keV - 1.7 MeV) flux and spectral variability of the transient source GRO J1719-24 covering a 1000…

astro-ph2004★ 45 cited

VLBA Polarization Observations of Markarian 421 After a Gamma-Ray High State

B. Glenn Piner, Philip G. Edwards

We present four high dynamic range, dual-circular polarization, Very Long Baseline Array (VLBA) observations at 22 GHz of Markarian 421, taken throughout the year following the sou…

astro-ph2004★ 24 cited

Small-scale anisotropy and intermittency in high and low-latitude solar wind

A. Bigazzi, L. Biferale, S. M. A. Gama +1

We analyze low and high--latitude fast solar wind data from the Ulysses spacecraft from 1992 to 1994 using a a systematic method to analyse the anisotropic content of the magnetic…

astro-ph2004★ 133 cited

Planets and IR Excesses: Preliminary Results from a Spitzer/MIPS Survey of Solar-Type Stars

C. A. Beichman, G. Bryden, G. H. Rieke +10

As part of a large Spitzer/MIPS GTO program, we have searched for infrared excesses due to debris disks toward 26 FGK field stars known from radial velocity (RV) studies to have on…

astro-ph2004★ 46 cited

STIS ultraviolet/optical spectroscopy of `warm' ultraluminous infrared galaxies

D. Farrah, J. A. Surace, S. Veilleux +2

(Abridged) We present high spatial resolution ultraviolet and optical spectroscopy, obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, of…

astro-ph2004★ 34 cited

Millimeter Wavelength Brightness Fluctuations of the Atmosphere Above the South Pole

R. S. Bussmann, W. L. Holzapfel, C. L. Kuo

We report measurements of the millimeter wavelength brightness fluctuations produced by the atmosphere above the South Pole made with the Arcminute Cosmology Bolometer Array Receiv…

astro-ph2004★ 61 cited

Cosmological Parameter Constraints as Derived from the Wilkinson Microwave Anisotropy Probe Data via Gibbs Sampling and the Blackwell-Rao Estimator

M. Chu, H. K. Eriksen, L. Knox +5

We study the Blackwell-Rao (BR) estimator of the probability distribution of the angular power spectrum, P(C_l|d), by applying it to samples of full-sky no-noise CMB maps generated…

astro-ph2004★ 258 cited

The Truncated Disk of CoKu Tau/4

Paola D'Alessio, Lee Hartmann, Nuria Calvet +11

We present a model of a dusty disk with an inner hole which accounts for the Spitzer Space Telescope Infrared Spectrograph observations of the low-mass pre-main sequence star CoKu…

astro-ph2004★ 366 cited

The On-Orbit Performance of the Galaxy Evolution Explorer

P. Morrissey, D. Schiminovich, T. A. Barlow +35

We report the first year on-orbit performance results for the Galaxy Evolution Explorer (GALEX), a NASA Small Explorer that is performing a survey of the sky in two ultraviolet ban…

astro-ph2004★ 2.5k cited

The Galaxy Evolution Explorer: A Space Ultraviolet Survey Mission

D. Christopher Martin, James Fanson, David Schiminovich +21

We give an overview of the Galaxy Evolution Explorer (GALEX), a NASA Explorer Mission launched on April 28, 2003. GALEX is performing the first space UV sky-survey, including imagi…

astro-ph2004★ 168 cited

The DEEP Groth Strip Galaxy Redshift Survey. III. Redshift Catalog and Properties of Galaxies

Benjamin J. Weiner, Andrew C. Phillips, S. M. Faber +16

The Deep Extragalactic Evolutionary Probe (DEEP) is a series of spectroscopic surveys of faint galaxies, targeted at the properties and clustering of galaxies at redshifts z ~ 1. W…

astro-ph2004★ 56 cited

The CMB temperature power spectrum from an improved analysis of the Archeops data

M. Tristram, G. Patanchon, J. F. Macias-Perez +47

We present improved results on the measurement of the angular power spectrum of the Cosmic Microwave Background (CMB) temperature anisotropies using the data from the last Archeops…

astro-ph2004★ 63 cited

The Lens Redshift and Group Environment for HE 0435-1223

Nicholas D. Morgan, Christopher S. Kochanek, Olga Pevunova +1

The redshift of the galaxy lensing HE 0435-1223 is 0.4546 +/- 0.0002, based on observations obtained with the Low Dispersion Survey Spectrograph 2 (LDSS2) on the Magellan Consortiu…

astro-ph2004★ 936 cited

Mid-Infrared Selection of Active Galaxies

Daniel Stern, Peter Eisenhardt, Varoujan Gorjian +12

Mid-infrared photometry provides a robust technique for identifying active galaxies. While the ultraviolet to mid-infrared continuum of normal galaxies is dominated by the composit…

astro-ph2004★ 18 cited

X-ray Reflection from Inhomogeneous Accretion Disks: II. Emission Line Variability and Implications for Reverberation Mapping

D. R. Ballantyne, N. J. Turner, A. J. Young

One of the principal scientific objectives of the upcoming Constellation-X mission is to attempt to map the inner regions of accretion disks around black holes in Seyfert galaxies…

astro-ph2004★ 151 cited

A Chandra Survey of Quasar Jets: First Results

H. L. Marshall, D. A. Schwartz, J. E. J. Lovell +6

We present results from Chandra X-ray imaging and spectroscopy of a flux-limited sample of flat spectrum radio-emitting quasars with jet-like extended structure. Twelve of twenty q…

astro-ph2004★ 6k cited

HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere

K. M. Gorski, E. Hivon, A. J. Banday +4

HEALPix -- the Hierarchical Equal Area iso-Latitude Pixelization -- is a versatile data structure with an associated library of computational algorithms and visualization software…

astro-ph2004★ 23 cited

Disks, Tori, and Cocoons: Emission and Absorption Diagnostics of AGN Environments

R. Morganti, L. J. Greenhill, A. B. Peck +2

One of the most important problems in the study of active galaxies is understanding the detailed geometry, physics, and evolution of the central engines and their environments. The…

astro-ph2004★ 12 cited

Apparent Stellar Wobble by a Planet in a Circumstellar Disk: Limitations on Planet Detection by Astrometry

Taku Takeuchi, T. Velusamy, D. N. C. Lin

Astrometric detection of a stellar wobble on the plane of the sky will provide us a next breakthrough in searching extrasolar planets. The Space Interferometry Mission (SIM) is exp…

astro-ph2004★ 7 cited

Spacecraft Tracking with the SKA

D. L. Jones

The possibility of using the SKA for occasional support of scientific space missions should be considered, along with all other science goals, in the design of the array. The benef…

astro-ph2004★ 48 cited

Radial Distribution of Dust Grains Around HR 4796A

Z. Wahhaj, D. W. Koerner, D. E. Backman +4

We present high-dynamic-range images of circumstellar dust around HR 4796A that were obtained with MIRLIN at the Keck II telescope at lambda = 7.9, 10.3, 12.5 and 24.5 um. We also…

astro-ph2004★ 25 cited

Astrometric Discovery of GJ 164B

Steven H. Pravdo, Stuart B. Shaklan, Todd Henry +1

We discovered a low-mass companion to the M-dwarf GJ 164 with the CCD-based imaging system of the Stellar Planet Survey (STEPS) astrometric program. The existence of GJ 164B was co…

astro-ph2004★ 15 cited

Hydrodynamical simulations of the jet in the symbiotic star MWC 560 I. Structure, emission and synthetic absorption line profiles

Matthias Stute, Max Camenzind, Hans Martin Schmid

We performed hydrodynamical simulations with and without radiative cooling of jet models with parameters representative for the symbiotic system MWC 560. For symbiotic systems we h…