Search Publications
Magnetic Flux Conservation in the Heliosheath Including Solar Cycle Variations of Magnetic Field Intensity
Tóth, G.; Richardson, J. D.; Opher, M. +2 more
In the heliosheath (HS), Voyager 2 has observed a flow with constant radial velocity and magnetic flux conservation. Voyager 1, however, has observed a decrease in the flow’s radial velocity and an order of magnitude decrease in magnetic flux. We investigate the role of the 11 yr solar cycle variation of the magnetic field strength on the magnetic…
An imaging and spectroscopic study of the planetary nebulae in NGC 5128 (Centaurus A). Planetary nebulae catalogues
Rejkuba, M.; Walsh, J. R.; Walton, N. A.
Context. Planetary nebulae (PNe) are excellent tracers of the common low mass stars through their strong and narrow emission lines. The velocities of large numbers of PNe are excellent tracers of galaxy kinematics. NGC 5128, the nearest large early-type galaxy, offers the possibility to gather a large sample.
Aims: Imaging and spectroscopic o…
Hall and finite Larmor radius effects on the dipolarization fronts associated with interchange instability
Zhang, T. L.; Nakamura, R.; Dunlop, M. W. +3 more
In this paper, we established a Hall-finite Larmor radius (FLR) MHD model by including Hall and finite Larmor radius (FLR) effects to study the dipolarization fronts (DFs) produced by the interchange instability in the magnetotail. The results indicate that the Hall effect on the scale of inertial length determines the distributions of electric fi…
Revealing a hard X-ray spectral component that reverberates within one light hour of the central supermassive black hole in Ark 564
Turner, T. J.; Kraemer, S. B.; Reeves, J. N. +4 more
Context. Arakelian 564 (Ark 564, z = 0.0247) is an X-ray-bright narrow-line Seyfert 1 galaxy. By using advanced X-ray timing techniques, an excess of "delayed" emission in the hard X-ray band (4-7.5 keV) following about 1000 s after "flaring" light in the soft X-ray band (0.4 - 1 keV) was recently detected.
Aims: We report on the X-ray spectr…
Remnant buried ice in the equatorial regions of Mars: Morphological indicators associated with the Arsia Mons tropical mountain glacier deposits
Head, James W.; Marchant, David R.; Scanlon, Kathleen E.
The fan-shaped deposit (FSD) on the western and northwestern flanks of Arsia Mons is the remnant of tropical mountain glaciers, deposited several tens to hundreds of millions of years ago during periods of high spin-axis obliquity. Previous workers have argued that the Smooth Facies in the FSD contains a core of ancient glacial ice. Here, we find …
Compensated-current instability of kinetic Alfvén waves
De Keyser, J.; Malovichko, P.; Voitenko, Y.
We study a non-resonant instability of kinetic Alfvén waves (KAWs) driven by compensated currents. Such currents set up in response to energetic ion beams occurring in many space and astrophysical plasmas, like foreshock regions in the solar wind and around supernova remnants. Kinetic effects of the background ion gyroradius make the KAW instabili…
Core Shapes and Orientations of Core-Sérsic Galaxies
Graham, Alister W.; Dullo, Bililign T.
The inner and outer shapes and orientations of core-Sérsic galaxies may hold important clues to their formation and evolution. We have therefore measured the central and outer ellipticities and position angles for a sample of 24 core-Sérsic galaxies using archival Hubble Space Telescope (HST) images and data. By selecting galaxies with core-Sérsic…
Pre-hibernation performances of the OSIRIS cameras onboard the Rosetta spacecraft
Barbieri, M.; Jorda, L.; Sierks, H. +12 more
Context. The ESA cometary mission Rosetta was launched in 2004. In the past years and until the spacecraft hibernation in June 2011, the two cameras of the OSIRIS imaging system (Narrow Angle and Wide Angle Camera, NAC and WAC) observed many different sources. On 20 January 2014 the spacecraft successfully exited hibernation to start observing the…
Investigating the kinematics of coronal mass ejections with the automated CORIMP catalog
Byrne, Jason P.
Studying coronal mass ejections (CMEs) in coronagraph data can be challenging due to their diffuse structure and transient nature, compounded by the variations in their dynamics, morphology and frequency of occurrence. The large amounts of data available from missions like the Solar and Heliospheric Observatory (SOHO) make manual cataloging of CME…
Infrared dark clouds on the far side of the Galaxy
Menten, K. M.; Csengeri, T.; van der Tak, F. F. S. +5 more
Context. Infrared dark clouds are the coldest and densest portions of giant molecular clouds. The most massive ones represent some of the most likely birthplaces for the next generation of massive stars in the Milky Way. Because a strong mid-IR background is needed to make them appear in absorption, they are usually assumed to be nearby.
Aims…