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Positron production and annihilation in the Milky Way
Prantzos, Nikos
SNIa in the Milky Way bulge may supply about 12% of the positrons required by observations of the 511 keV emission from the inner Galaxy, while positrons from disk SNIa may account for the totality of that emission. It is argued here that most of the disk positrons propagate away from the disk (due to the low density environment) and the resulting…
Modeling accelerated pick-up ion distributions at an interplanetary shock
Baring, Matthew G.; Summerlin, Errol J.
The acceleration of interstellar pick-up ions as well as solar wind species has been observed at a multitude of interplanetary (IP) shocks by different spacecraft. The efficiency of injection of the pick-up ion component differs from that of the solar wind, and is expected to be strongly enhanced at highly oblique and quasi-perpendicular shock eve…
Swift Observations of the Highly X-Ray Variable Narrow-Line Seyfert 1 Galaxy RX J0148.3-2758
O'Brien, Paul T.; Schady, Patricia; Leighly, Karen M. +4 more
We report on Swift observations of the narrow-line Seyfert 1 galaxy RX J0148.3-2758. It was observed for 41.6 ks in 2005 May and for 15.8 ks in 2005 December. On short as well as on long timescales, RX J0148.3-2758 is a highly variable source. It doubles its X-ray flux within 18-25 ks. The observation of 2005 December 9, which had a flux 4 times l…
The Astro-E2/XRS-2 helium insert system
Mitsuda, K.; Fujimoto, R.; McCammon, D. +5 more
The X-ray Spectrometer (XRS-2) instrument on the Japanese Space Agency (JAXA) Astro-E2 spacecraft will measure faint X-ray emissions in the energy range of 0.2-10 keV. A square array of 32 X-ray microcalorimeters used will be able to distinguish individual photons to better than 10 eV at 6 keV, with a quantum efficiency near 100%. The detectors ar…
Heliospheric ion energization due to emerging CME shocks
Bale, S. D.; Roth, I.
Formation of inhomogeneous electromagnetic structures with gradients in magnetic field and intrinsic electric fields is commonly observed in magnetized plasmas. Heliospheric plasmas are susceptible to formation of localized, supersonically propagating electromagnetic inhomogeneities. Coronal relaxation may result in an emergence close to solar sur…
Application of an orbital radar sounder model to detecting Martian polar subsurface features
Farrell, William M.; Xu, Yanbin; Cummer, Steven A.
A model to simulate the complete planetary orbital radar sounder problem is presented in this paper. The subsurface features and the ionosphere will not only bring ambiguity to the collected radar sounder data, but also critically affect instrument capabilities. These environmental uncertainties generate a compelling need for meaningful quantitati…
Wave acceleration of the fast solar wind
Ofman, Leon
Observations show that the solar wind exhibits two modes of outflow: the slow (∼400 km s -1), high density, highly variable wind that emerges from equatorial solar regions, and the high latitude, fast (∼800 km s -1), low density, steady solar wind. The bi-modal solar wind outflow is most evident near minima of solar activity.…
Common Proper Motion Search for Faint Companions Around Early-Type Field Stars – Progress Report
Huélamo, N.; Foellmi, C.; Chauvin, G. +5 more
The multiplicity of early-type stars is still not well established. The derived binary fraction is different for individual star forming regions, suggesting a connection with the age and the environment conditions. The few studies that have investigated this connection do not provide conclusive results. To fill in this gap, we started the first de…
Search for causes of the low epithermal neutron flux anomaly in the Arabia Terra region (Mars)
Head, J. W.; Neukum, G.; Werner, S. +8 more
A geologic analysis of 274 images acquired by the high-resolution MOC camera onboard the Mars Global Surveyor spacecraft within the Arabia Terra low neutron flux anomaly (which is indicative of an anomalously high abundance of hydrogen: up to 16 wt % of the equivalent amount of water) was performed. Correlation between the enhanced abundance of eq…
A criterion to discriminate between solar and cosmic ray forcing of the terrestrial climate
Fichtner, H.; Scherer, K.; Heber, B.
There is increasing evidence that there exist interstellar-terrestrial relations and that the heliosphere's effectivity to serve as a protecting shield for the Earth, specifically against cosmic rays, is varying in time. Nonetheless, a debate is going on whether, amongst other drivers, the Sun or the cosmic rays are influencing the terrestrial cli…