Search Publications
Auroral electron precipitation and flux tube erosion in Titan’s upper atmosphere
Coates, A. J.; Jones, G. H.; Wellbrock, A. +4 more
Cassini dasta shows that Titan’s atmosphere strongly depletes the electron content in Saturn’s flux tubes, producing features known as electron bite-outs, which indicate that the flux of auroral electrons decreases over time. To understand this process we have developed a time-dependent two-stream model, which uses field line geometries and drift …
A new population of planetary nebulae discovered in the Large Magellanic Cloud (IV): the outer LMC
Parker, Quentin A.; Reid, Warren A.
We have extended our planetary nebulae (PNe) survey to the outer ∼64 deg2 of the Large Magellanic Cloud (LMC) using maps from the Magellanic Cloud Emission Line Survey (MCELS) and the UK Schmidt Telescope (UKST) Hα survey. Although the MCELS survey has poorer ∼5 arcsec resolution than both the UKST Hα survey and the original Hα median s…
On the Road to More Realistic Galaxy Cluster Simulations: The Effects of Radiative Cooling and Thermal Feedback Prescriptions on the Observational Properties of Simulated Galaxy Clusters
O'Shea, Brian W.; Burns, Jack O.; Smith, Britton D. +3 more
Flux-limited X-ray surveys of galaxy clusters show that clusters come in two roughly equally proportioned varieties: "cool core" clusters (CCs) and non-"cool core" clusters (NCCs). In previous work, we have demonstrated using cosmological N-body + Eulerian hydrodynamic simulations that NCCs are often consistent with early major merger events that …
A study on subarcsecond scales of the ammonia and continuum emission toward the G16.59-0.05 high-mass star-forming region
Sanna, A.; Pestalozzi, M.; Cesaroni, R. +4 more
Aims: We wish to investigate the structure, velocity field, and stellar content of the G16.59-0.05 high-mass star-forming region, where previous studies have established the presence of two almost perpendicular (NE-SW and SE-NW), massive outflows, and a rotating disk traced by methanol maser emission.
Methods: We performed Very Large Arr…
Gradient estimation using configurations of two or three spacecraft
Vogt, J.; Blagau, A.; Sorbalo, E. +1 more
The forthcoming three-satellite mission Swarm will allow us to investigate plasma processes and phenomena in the upper ionosphere from an in-situ multi-spacecraft perspective. Since with less than four points in space the spatiotemporal ambiguity cannot be resolved fully, analysis tools for estimating spatial gradients, wave vectors, or boundary p…
Real or Interloper? The Redshift Likelihoods of z > 8 Galaxies in the HUDF12
Pirzkal, Nor; Coe, Dan; Ryan, Russell +4 more
In the absence of spectra, the technique of fitting model galaxy template spectra to observed photometric fluxes has become the workhorse method for determining the redshifts and other properties for high-z galaxy candidates. In this paper, we present an analysis of the most recent and possibly most distant galaxies (z ~ 8-12) discovered in the Hu…
Grain Destruction in a Supernova Remnant Shock Wave
Blair, William P.; Raymond, John C.; Ghavamian, Parviz +4 more
Dust grains are sputtered away in the hot gas behind shock fronts in supernova remnants (SNRs), gradually enriching the gas phase with refractory elements. We have measured emission in C IV λ1550 from C atoms sputtered from dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop. Overall, the intensity observed behind the sho…
Asymmetries of the magnetic field line draping shape around Venus
Kallio, E.; Zhang, T. L.; Wang, C. +1 more
The magnetic field data observed by Venus Express (VEX) from April 2006 to December 2009 are analyzed in order to describe the magnetic configuration around Venus. All the magnetic observations are organized in a coordinate system which is determined by the solar wind (SW) flow and the interplanetary magnetic field. By averaging and compiling the …
Non-adiabatic electron behaviour due to short-scale electric field structures at collisionless shock waves
Schwartz, S. J.; See, V.; Cameron, R. F.
Under sufficiently high electric field gradients, electron behaviour within exactly perpendicular shocks is unstable to the so-called trajectory instability. We extend previous work paying special attention to short-scale, high-amplitude structures as observed within the electric field profile. Via test particle simulations, we show that such stru…
Ion distributions upstream and downstream of the Earth's bow shock: first results from Vlasiator
Vainio, R.; Palmroth, M.; Pokhotelov, D. +3 more
A novel hybrid-Vlasov code, Vlasiator, is developed for global simulations of magnetospheric plasma kinetics. The code is applied to model the collisionless bow shock on scales of the Earth's magnetosphere in two spatial dimensions and three dimensions in velocity space retrieving ion distribution functions over the entire foreshock and magnetoshe…