Search Publications
The 10 µm Feature of M-Type Stars in the Large Magellanic Cloud and the Dust Condensation Sequence
Abraham, P.; Speck, A. K.; Dijkstra, C. +1 more
We present 7-14 µm Infrared Space Observatory (ISO) spectroscopy of 12 M-type evolved stars in the Large Magellanic Cloud (LMC), in order to study the dust mineralogy and condensation process around these stars. The sample stars show a broad dust feature in the 7-14 µm region, which is seen in either emission or (self-) absorption. The…
Magnetopause current as seen by Cluster
Balogh, A.; Dunlop, M. W.
The four-spacecraft, magnetic field measurements on Cluster can be combined to produce an accurate determination of the electric current in the magnetopause boundary during stable magnetopause crossings. For events that are planar on the scale of the spacecraft configuration, the thickness of the current layer can be accurately estimated from its …
X-ray bright optically inactive galaxies in XMM-Newton/Sloan Digital Sky Survey fields: more diluted than absorbed?
Georgakakis, A.; Georgantopoulos, I.
We explore the properties of X-ray bright optically inactive galaxies (XBONGs) detected in the 0.5-8 keV spectral band in 20 public XMM-Newton fields overlapping with the Sloan Digital Sky Survey (SDSS). We constrain our sample to optically extended systems with logfX/fopt > -2 that have spectroscopic identifications avail…
The Model Dependence of Solar Energetic Particle Mean Free Paths under Weak Scattering
Mason, G. M.; Zhang, M.; Qin, G. +2 more
The mean free path is widely used to measure the level of solar energetic particles' diffusive transport. We model a solar energetic particle event observed by Wind STEP at 0.31-0.62 MeV nucleon-1, by solving the focused transport equation using the Markov stochastic process theory. With different functions of the pitch angle diffusion …
High-Mass Triple Systems: The Classical Cepheid Y Carinae
Evans, Nancy Remage; Carpenter, Kenneth G.; Robinson, Richard +2 more
We have obtained a Hubble Space Telescope STIS ultraviolet high-dispersion echelle-mode spectrum of the binary companion of the double-mode classical Cepheid Y Car. The velocity measured for the hot companion from this spectrum is very different from reasonable predictions for binary motion, implying that the companion is itself a short-period bin…
Comparison of Interplanetary Disturbances at the NEAR Spacecraft with Coronal Mass Ejections at the Sun
Russell, C. T.; Andrews, M. D.; Mulligan, T. +4 more
We examined interplanetary (IP) magnetic field disturbances recorded by the Near Earth Asteroid Rendezvous-Shoemaker spacecraft (NEAR) when it was above either the east or west solar limb as seen from Earth; we then identified the associated coronal mass ejections (CMEs) detected above the limbs by the SOHO LASCO coronagraph. We found 10 cases in …
Homogeneous Photometry. V. The Globular Cluster NGC 4147
Catelan, M.; Stetson, Peter B.; Smith, Horace A.
New BVRI broadband photometry and astrometry are presented for the globular cluster NGC 4147, based upon measurements derived from 524 ground-based CCD images mostly either donated by colleagues or retrieved from public archives. We have also reanalyzed five exposures of the cluster obtained with WFPC2 on the Hubble Space Telescope in the F439W an…
The broad-band X-ray spectrum of the blazar PKS B1830-211 by Chandra and INTEGRAL
Piro, L.; de Rosa, A.; Tramacere, A. +6 more
In this paper we present a broad-band study of the X-ray emission of the blazar PKS 1830-211 based on Chandra and INTEGRAL observations. Notwithstanding the high redshift (z=2.507), it is a bright X-ray source (F(2-10 keV) ≃ 10-11 erg cm-2 s-1), due to gravitational lensing by an intervening galaxy at z=0.89. Previ…
A dichotomy in the orientation of dust and radio jets in nearby low-power radio galaxies
de Zeeuw, P. T.; Verdoes Kleijn, G. A.
We examine the properties of central dust in nearby quiescent and active early-type galaxies. The active galaxies are low-power radio galaxies with Fanaroff & Riley type I or I/II radio jets. We focus on (a) the comparison of the dust distributions in the active and quiescent galaxy samples; and (b) the relation between the radio jet and dust …
Accurate and approximate calculations of Raman scattering in the atmosphere of Neptune
Sromovsky, L. A.
Raman scattering by H 2 in Neptune's atmosphere has significant effects on its reflectivity for λ<0.5 µm, producing baseline decreases of ∼20% in a clear atmosphere and ∼10% in a hazy atmosphere. However, few accurate Raman calculations are carried out because of their complexity and computational costs. Here we present the fir…