Search Publications
Kinetic aspects of foreshock cavities
Schwartz, Steven J.; Meziane, Karim; Horbury, Timothy S. +2 more
We have investigated the kinetic signatures within, and at the edges of, a foreshock cavity. Such cavities are believed to be formed when an isolated collection of interplanetary magnetic field lines connect to quasi-parallel regions of the Earth's bow shock, allowing energetic ions to flow upstream and excavate a local cavity. Observations by the…
Probing the Pulsar Wind Nebula of PSR B0355+54
Cropper, M.; McGowan, K. E.; Kennea, J. A. +3 more
We present XMM-Newton and Chandra X-ray observations of the middle-aged radio pulsar PSR B0355+54. Our X-ray observations reveal emission not only from the pulsar itself, but also from a compact diffuse component extending ~50" in the opposite direction to the pulsar's proper motion. There is also evidence for the presence of fainter diffuse emiss…
On the Lack of a Soft X-Ray Excess from Clusters of Galaxies
Bregman, Joel N.; Lloyd-Davies, Edward J.
A soft X-ray excess has been claimed to exist in and around a number of galaxy clusters, and this emission has been attributed to the warm-hot intergalactic medium that may constitute most of the baryons in the local universe. We have reexamined a study of the XMM-Newton observations on this topic by Kaastra and coworkers and find that the X-ray e…
Orbital elements, masses and distance of λ Scorpii A and B determined with the Sydney University Stellar Interferometer and high-resolution spectroscopy
Uytterhoeven, K.; Aerts, C.; Tuthill, P. G. +7 more
The triple system HD158926 (λSco) has been observed interferometrically with the Sydney University Stellar Interferometer, and the elements of the wide orbit have been determined. These are significantly more accurate than the previous elements found spectroscopically. The inclination of the wide orbit is consistent with the inclination previously…
Attempts to measure the magnetic field of the pulsating B star ν Eridani
Neiner, C.; Henrichs, H. F.; Schnerr, R. S. +1 more
We report on attempts to measure the magnetic field of the pulsating B star ν Eridani with the Musicos spectropolarimeter attached to the 2 m telescope at the Pic du Midi, France. This object is one of the most extensively studied stars for pulsation modes, and the existence of a magnetic field was suggested from the inequality of the frequency se…
An INTEGRAL/IBIS view of young Galactic SNRs through the 44Ti gamma-ray lines
Ballet, J.; Decourchelle, A.; Vink, J. +3 more
We present preliminary results of INTEGRAL/IBIS observations on Cas A, Tycho and Vela Junior supernova remnants in the line emission of 44Ti. This radioactive nucleus is thought to be exclusively produced in supernovae during the first stages of the explosion. It has a lifetime of about 87 yr and is then the best indicator of young SNRs…
Line profiles of water for the photon dominated region and embedded sources in the S140 region
Spaans, M.; Poelman, D. R.
H_2O is a key ingredient in many interstellar environments, like photon dominated regions and star forming clouds. It plays an important role in the oxygen chemistry and can act as a coolant in dense interstellar clouds and shocks. Observations and modelling of water lines thus provide powerful diagnostics of the physical conditions in interstella…
Carbon Monoxide in Comet 9P/Tempel 1 before and after the Deep Impact Encounter
Weaver, Harold A.; Feldman, Paul D.; A'Hearn, Michael F. +4 more
One of the goals of the Hubble Space Telescope program to observe periodic comet 9P/Tempel 1 in conjunction with NASA's Deep Impact mission was to study the generation and evolution of the gaseous coma resulting from the impact. For this purpose, the Solar Blind Channel of the Advanced Camera for Surveys was used with the F140LP filter, which is s…
Solar Energetic Particles and Radio-silent Fast Coronal Mass Ejections
Klein, K. -L.; Posner, A.; Marqué, C.
Both solar flares and shock waves driven by fast coronal mass ejections (CMEs) can accelerate charged particles in the solar corona and create transient enhancements of solar energetic particle fluxes in interplanetary space (SEP events). Fast CMEs and flares often occur together, which makes it difficult to directly identify the actual source of …
Physical Conditions in the Interstellar Medium toward HD 185418
Abel, N. P.; Ferland, G. J.; Srianand, R. +1 more
We have developed a complete model of the hydrogen molecule as part of the spectral simulation code Cloudy. Our goal is to apply this to spectra of high-redshift star-forming regions where H2 absorption is seen, but where few other details are known, to understand its implication for star formation. The microphysics of H2 is …