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Using an MHD simulation to interpret the global context of a coronal mass ejection observed by two spacecraft
Lario, D.; Odstrcil, D.; Riley, Pete +4 more
In late February 1999 the ACE spacecraft observed a coronal mass ejection (CME) at 1 AU, in the ecliptic plane. Thirteen days later, Ulysses observed a CME at 5 AU and 22°S. We present a detailed analysis of the plasma, magnetic field, and composition signatures of these two events. On the basis of this comparison alone, it is not clear that the t…
3D dynamical evolution of the interstellar gas in the Gould Belt
Grenier, I. A.; Perrot, C. A.
The dynamical evolution of the Gould Belt has been modelled in 3D and compared to the spatial and velocity distributions of all HI and H2 clouds found within a few hundred parsecs from the Sun and to the Hipparcos distances of the nearby OB associations. The model describes the expansion of a shock wave that sweeps momentum from the amb…
Dust Grain Size Distributions from MRN to MEM
Sofia, Ulysses J.; Gordon, K. D.; Clayton, Geoffrey C. +2 more
Employing the maximum entropy method (MEM) algorithm, we fit interstellar extinction measurements that span the wavelength range 0.125-3 µm. We present a uniform set of MEM model fits, all using the same grain materials, optical constants, and abundance constraints. In addition, we are taking advantage of improved UV and IR data and better e…
An ISOCAM survey through gravitationally lensing galaxy clusters. I. Source lists and source counts for A370, A2218 and A2390
Kneib, J. -P.; Altieri, B.; Elbaz, D. +11 more
ESA's Infrared Space Observatory (ISO) was used to perform a deep survey with ISOCAM through three massive gravitationally lensing clusters of galaxies. The total area surveyed depends on source flux, with nearly seventy square arcminutes covered for the brighter flux levels in maps centred on the three clusters Abell 370, Abell 2218 and Abell 239…
A Multitransition CO Study of the Antennae Galaxies NGC 4038/9
Kuno, Nario; Zhu, Ming; Seaquist, E. R.
For the Antennae interacting galaxy pair, we have obtained high-quality, fully sampled 12CO J=1-0 and 3-2 maps of the regions surrounding the nuclei and the area of overlap between the two galaxies. The maps possess an angular resolution of 15" or 1.5 kpc, so far the highest resolution maps available at both the J=1-0 and 3-2 transition…
Observational evidence of new current sheets trailing coronal mass ejections
Webb, D. F.; Riley, P.; Burkepile, J. +1 more
Field line reconnection in the wake of coronal mass ejections (CMEs) is a fundamental aspect of some magnetically driven eruptive flare/CME models, e.g., the standard reconnection model [cf. Svestka and Cliver, 1992]. This model features a growing hot loop arcade beneath a rising X-type neutral point that is connected to the retreating CME. In mod…
Caught in the act: A helium-reionizing quasar near the line of sight to Q0302-003
Reimers, D.; Jakobsen, P.; Jansen, R. A. +1 more
We report the discovery of a quasar at z=3.050+/-0.003, closely coincident in redshift with the isolated low-opacity feature seen near z =~ 3.056 in the otherwise black portion of the He Ii Gunn-Peterson absorption trough seen toward the z=3.286 background quasar Q0302-003, located 6farcm5 away on the sky. We explore plausible models for the He Ii…
Interstellar Deuterium, Nitrogen, and Oxygen Abundances toward GD 246, WD 2331-475, HZ 21, and Lanning 23: Results from the FUSE Mission
Howk, J. Christopher; Chayer, Pierre; Hébrard, Guillaume +3 more
The interstellar abundances of D I, N I, and O I in the local ISM are studied using high-resolution spectra of four hot white dwarfs. The spectra of GD 246, WD 2331-475, HZ 21, and Lan 23 were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) in the wavelength range 905-1187 Å. The line of sight to GD 246 probes the Local Interstella…
Atomic Deuterium/Hydrogen in the Galaxy
Linsky, Jeffrey L.
An accurate value of the D/H ratio in the local interstellar medium (LISM) and a better understanding of the D/H variations with position in the Galactic disk and halo are vitally important questions as they provide information on the primordial D/H ratio in the Galaxy at the time of the protosolar nebula, and the amount of astration and mixing in…
XMM-Newton confirmation of soft X-ray excess emission in clusters of galaxies - The discovery of O VII emission from an extended warm baryonic component
Kaastra, J. S.; Tamura, T.; den Herder, J. W. +2 more
We investigate a sample of 14 clusters of galaxies observed with XMM-Newton in a search for soft X-ray excess emission. In five of these clusters a significant soft excess is evident. This soft X-ray excess is compared with the thermal emission from both the hot intracluster gas and any cooling (flow) gas that may be present. A warm (kT=0.2 keV), …