Search Publications
Electron velocity distribution and lion roars in the magnetosheath
Fazakerley, A. N.; Maksimovic, M.; Schwartz, S. J. +1 more
Whistler waves which are termed "lion roars" in the magnetosheath are studied using data obtained by the Spectrum Analyser (SA) of the Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment aboard Cluster. Kinetic theory is then employed to obtain the theoretical expression for the whistler wave with electron temperature anisotropy whic…
The spectral energy distribution of PKS 2004-447: a compact steep-spectrum source and possible radio-loud narrow-line Seyfert 1 galaxy
Kataoka, J.; Boller, Th.; Welsh, W. F. +10 more
An investigation of the spectral energy distribution (SED) of the compact steep-spectrum (CSS) source and possible radio-loud narrow-line Seyfert 1 galaxy (NLS1), PKS 2004-447, is presented. Five out of six well-studied radio-loud NLS1 share this dual classification [optically defined as an NLS1 with radio definition of a CSS or gigahertz-peaked s…
Differential Microlensing of the Continuum and Broad Emission Lines in SDSS J0924+0219, the Most Anomalous Lensed Quasar
Keeton, Charles R.; Schechter, Paul L.; Burles, Scott +1 more
SDSS J092455.87+021924.9 is the most glaring example of a gravitational lens with anomalous flux ratios; optical broadband photometry shows image D to be a factor of 12 fainter than expected for smooth lens potentials. We report spectroscopy showing that the anomaly is present in the broad emission line flux ratios as well. There are differences b…
The Statistical Relationship between the Photospheric Magnetic Parameters and the Flare Productivity of Active Regions
Jing, Ju; Wang, Haimin; Song, Hui +2 more
Using line-of-sight Michelson Doppler Imager (MDI) magnetograms of 89 active regions and Solar Geophysical Data (SGD) flare reports, we explored, for the first time, the magnitude scaling correlations between three parameters of magnetic fields and the flare productivity of solar active regions. These parameters are (1) the mean value of spatial m…
2MASS J22521073-1730134: A Resolved L/T Binary at 14 Parsecs
Burgasser, Adam J.; Reid, I. Neill; Cruz, K. L. +1 more
NICMOS images of the nearby late-type L dwarf 2MASS J22521073-1730134 (DENIS-P J225210.73-173013.4) show that it is a close double, separation 0.13". The companion is 1.0 mag fainter than the primary in the F110W passband and 1.55 mag fainter in the F170M images. The latter passband is centered on the 1.6 µm methane band. The small separatio…
Probing isotopic ratios at z = 0.89: molecular line absorption in front of the quasar PKS 1830-211
Combes, F.; Muller, S.; Guélin, M. +2 more
With the Plateau de Bure interferometer, we have measured the C, N, O and S isotopic abundance ratios in the arm of a spiral galaxy with a redshift of 0.89. The galaxy is seen face-on according to HST images. Its bulge intercepts the line of sight to the radio-loud quasar
Spectral State Transitions of the Ultraluminous X-Ray Sources X-1 and X-2 in NGC 1313
Feng, Hua; Kaaret, Philip
X-ray spectral state transitions are a key signature of black hole X-ray binaries and follow a well-defined pattern. We examined 12 XMM-Newton observations of the nearby spiral galaxy NGC 1313, which harbors two compact ultraluminous X-ray sources (ULXs), X-1 and X-2, in order to determine if the state transitions in ULXs follow the same pattern. …
Detection of sporadic impact flashes on the Moon: Implications for the luminous efficiency of hypervelocity impacts and derived terrestrial impact rates
Pallé, E.; Aceituno, J.; Ortiz, J. L. +8 more
We present the first redundant detection of sporadic impact flashes on the Moon from a systematic survey performed between 2001 and 2004. Our wide-field lunar monitoring allows us to estimate the impact rate of large meteoroids on the Moon as a function of the luminous energy received on Earth. It also shows that some historical well-documented my…
Initial interpretation of Titan plasma interaction as observed by the Cassini plasma spectrometer: Comparisons with Voyager 1
Coates, A. J.; Crary, F.; Johnson, R. E. +15 more
The Cassini plasma spectrometer (CAPS) instrument made measurements of Titan's plasma environment when the Cassini Orbiter flew through the moon's plasma wake October 26, 2004 (flyby TA). Initial CAPS ion and electron measurements from this encounter will be compared with measurements made by the Voyager 1 plasma science instrument (PLS). The comp…
C II Abundances in Early-Type Stars: Solution to a Notorious Non-LTE Problem
Przybilla, N.; Nieva, M. F.
We address a long-standing discrepancy between non-LTE analyses of the prominent C II 4267 and 6578/82 Å multiplets in early-type stars. A comprehensive non-LTE model atom of C II is constructed based on critically selected atomic data. This model atom is used for an abundance study of six apparently slow-rotating main-sequence and giant early B-t…