Search Publications
Density cavity in magnetic reconnection diffusion region in the presence of guide field
Deng, X. H.; Huang, S. Y.; Yuan, Z. G. +2 more
Understanding the structure of the diffusion region of magnetic reconnection is crucial to pinpoint the mechanism of energy conversion from magnetic field to plasma. Characteristics of a diffusion region with guide field (i.e., component reconnection) may be significantly different from those of a diffusion region without guide field (i.e., antipa…
PDR Model Mapping of Physical Conditions via Spitzer/IRS Spectroscopy of H2: Theoretical Success toward NGC 2023-South
Wolfire, M. G.; Sheffer, Y.; Hollenbach, D. J. +2 more
We use the Infrared Spectrograph on Spitzer to observe the southern part of the reflection nebula NGC 2023, including the Southern Ridge, which is a photodissociation region (PDR) par excellence excited by HD 37903. Five pure-rotational H2 emission lines are detected and mapped over and around the Southern Ridge in order to compare with…
The effect of the environment on the gas kinematics and the structure of distant galaxies
Aragón-Salamanca, Alfonso; Milvang-Jensen, Bo; Zaritsky, Dennis +10 more
With the aim of distinguishing between possible physical mechanisms acting on galaxies when they fall into clusters, we study the properties of the gas and the stars in a sample of 422 emission-line galaxies from the European Southern Observatory Distant Cluster Survey in different environments up to z∼ 1. We identify galaxies with kinematical dis…
XMM-Newton observations of the low-mass X-ray binary EXO 0748-676 in quiescence
Díaz Trigo, M.; Boirin, L.; Costantini, E. +2 more
The neutron star low-mass X-ray binary EXO 0748-676 started a transition from outburst to quiescence in August 2008, after more than 24 years of continuous accretion. The return of the source to quiescence has been monitored extensively by several X-ray observatories. Here, we report on four XMM-Newton observations elapsing a period of more than 1…
Spitzer spectra of evolved stars in ω Centauri and their low-metallicity dust production
van Loon, J. Th.; Gehrz, R. D.; Evans, A. +7 more
Dust production is explored around 14 metal-poor ([Fe/H]=-1.91 to -0.98) giant stars in the Galactic globular cluster ω Centauri using new Spitzer Infrared Spectrograph spectra. This sample includes the cluster's post-asymptotic giant branch (AGB) and carbon stars and is thus the first representative spectral study of dust production in a metal-po…
The water vapor plumes of Enceladus
Dong, Y.; Waite, J. H.; Hill, T. W. +2 more
The Cassini E3, E5, and E7 encounters with Enceladus probed the south polar plumes, where the Ion and Neutral Mass Spectrometer (INMS) measured neutral H2O molecular densities up to ∼109 cm-3. We have constructed a physical model for the expected water density in the plumes, based on supersonic radial outflow from …
Constructing Semi-Empirical Sunspot Models for Helioseismology
Gizon, L.; Schunker, H.; Pietarila, A. +1 more
One goal of helioseismology is to determine the subsurface structure of sunspots. In order to do so, it is important to understand first the near-surface effects of sunspots on solar waves, which are dominant. Here we construct simplified, cylindrically-symmetric sunspot models that are designed to capture the magnetic and thermodynamics effects c…
Discovery of the source HESS J1356-645 associated with the young and energetic PSR J1357-6429
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +195 more
Context. Several newly discovered very-high-energy (VHE; E > 100 GeV) γ-ray sources in the Galaxy are thought to be associated with energetic pulsars. Among them, middle-aged (≳ 104 yr) systems exhibit large centre-filled VHE nebulae, offset from the pulsar position, which result from the complex relationship between the pulsar wind …
A statistical study of the propagation characteristics of whistler waves observed by Cluster
Khotyaintsev, Yuri V.; Agapitov, Oleksiy; Krasnoselskikh, Vladimir +1 more
VLF waves play a crucial role in the dynamics of radiation belts, and are responsible for the loss and the acceleration of energetic electrons. Modeling wave-particle interactions requires the best possible knowledge for how wave energy and wave-normal directions are distributed in L-shells and for the magnetic latitudes of different magnetic acti…
Ion flow and momentum transfer in the Venus plasma environment
Fedorov, A.; Barabash, S.; Lundin, R. +3 more
An analysis of ion data from 390 Venus Express, VEX, orbits demonstrates that the flow of solar wind- and ionospheric ions near Venus is characterized by a marked asymmetry. The flow asymmetry of solar wind H + and ionospheric O + points steadily in the opposite direction to the planet's orbital motion, and is most pronounced…