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Probing the mass loss history of carbon stars using CO line and dust continuum emission
Ryde, N.; Olofsson, H.; Schöier, F. L.
An extensive modelling of CO line emission from the circumstellar envelopes around a number of carbon stars is performed. By combining radio observations and infrared observations obtained by ISO the circumstellar envelope characteristics are probed over a large radial range. In the radiative transfer analysis the observational data are consistent…
Including stereoscopic information in the reconstruction of coronal magnetic fields
Wiegelmann, T.; Neukirch, T.
We present a method to include stereoscopic information about the three-dimensional structure of flux tubes into the reconstruction of the coronal magnetic field. Due to the low plasma beta in the corona we can assume a force-free magnetic field, with the current density parallel to the magnetic field lines. Here we use linear force-free fields fo…
On the absence of wind bow-shocks around OB-runaway stars: Probing the physical conditions of the interstellar medium
Kaper, L.; Huthoff, F.
High-resolution IRAS maps are used to search for the presence of stellar-wind bow-shocks around high-mass X-ray binaries (HMXBs). Their high space velocities, recently confirmed with Hipparcos observations, combined with their strong stellar winds should result in the formation of wind bow-shocks. Except for the already known bow-shock around Vela…
The Detection of Pure Dark Matter Objects with Bent Multiply Imaged Radio Jets
Metcalf, R. Benton
When a gravitational lens produces two or more images of a quasar's radio jet the images can be compared to reveal the presence of small structures along one or more of the lines of sight. If mass is distributed smoothly on scales of <~107 Msolar, independent bends in the jet images on milliarcsecond scales will not be pro…
Afterglow Upper Limits for Four Short-Duration, Hard Spectrum Gamma-Ray Bursts
Frontera, F.; Price, P. A.; Berger, E. +22 more
We present interplanetary network localization, spectral, and time history information for four short-duration, hard spectrum gamma-ray bursts, GRB 000607, GRB 001025B, GRB 001204, and GRB 010119. All of these events were followed up with sensitive radio and optical observations (the first and only such bursts to be followed up in the radio to dat…
A 25 micron search for Vega-like disks around main-sequence stars with ISO
Kessler, M. F.; Siebenmorgen, R.; Dominik, C. +5 more
We present an ISO 25 mu m photometric survey of a sample of 81 nearby main-sequence stars in order to determine the incidence of ``warm'' dust disks. All stars were detected by ISO. We used an empirical relation to estimate the photospheric flux of the stars at 25 mu m. We find 5 stars (6%) with excess above the photospheric flux which we attribut…
Statistical Investigation and Modeling of Sungrazing Comets Discovered with the Solar and Heliospheric Observatory
Sekanina, Zdenek
More than 300 sungrazing comets, most of them discovered with the Solar and Heliospheric Observatory (SOHO) coronagraphs since the beginning of 1996, are known to belong to the Kreutz group or system. Moving about the Sun in similar orbits, they are of indisputably common parentage and represent by far the most extensive data set in the history of…
Relationship between CME Speed and Geomagnetic Storm Intensity
Venkatakrishnan, P.; Srivastava, Nandita
In this paper, we discuss the solar origin and interplanetary consequences of the coronal mass ejection of March 29, 2001 that was responsible for the most intense geomagnetic storm (DST ~ -377 nT) of the current solar cycle to date. A comparison of the CME of March 29, 2001, with a set of geo-effective halo CMEs associated with X-class…
The Likely Near-Infrared Counterpart to the Anomalous X-Ray Pulsar 1E 1048.1-5937
Chakrabarty, Deepto; Wang, Zhongxiang
We report our discovery of the likely near-infrared counterpart to the anomalous X-ray pulsar (AXP) 1E 1048.1-5937, using observations from the 6.5 m Baade (Magellan I) telescope in Chile. We derived a precise position for the X-ray source using archival data from the Chandra X-Ray Observatory. This position is inconsistent with a position reporte…
Relationship between discontinuities, magnetic holes, magnetic decreases, and nonlinear Alfvén waves: Ulysses observations over the solar poles
Balogh, A.; Lakhina, G. S.; Tsurutani, B. T. +6 more
Ulysses magnetic field data are used to study magnetic field microstructure over the solar poles. Magnetic holes (MHs) and magnetic decreases (MDs) are found to be located at the phase-steepened edges of nonlinear Alfvén waves. The phase-steepened edges (directional discontinuities) occur in time-coincidence with MHs, one edge of an MD, or through…