Search Publications
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…
Variable Ultraviolet Absorption in the Seyfert 1 Galaxy NGC 3516: The Case for Associated Ultraviolet and X-Ray Absorption
Turner, T. J.; Kraemer, S. B.; Crenshaw, D. M. +3 more
We present observations of the UV absorption lines in the Seyfert 1 galaxy NGC 3516, obtained at a resolution of λ/Δλ~40,000 with the Space Telescope Imaging Spectrograph (STIS) on 2000 October 1. The UV continuum was ~4 times lower than that observed during 1995 with the Goddard High Resolution Spectrograph (GHRS), and the X-ray flux from a conte…
The role of magnetic bald patches in surges and arch filament systems
Mandrini, C. H.; Schmieder, B.; Démoulin, P. +2 more
The short-lived active region (AR) NOAA 7968 was thoroughly observed all along its disk transit (June 3 to 10, 1996) from space and from the ground. During the early stage of its evolution, flux emerged in between the two main polarities and arch filament systems (AFS) were observed to be linked to this emergence. New bipoles and a related surge w…