Search Publications
Cluster observations of fast magnetosonic waves in the heliosphere current sheet
Dai, Lei; Wygant, John R.; Cattell, Cynthia A. +4 more
We present Cluster spacecraft observations of large-amplitude (δ|B|/|B|∼1) fast-mode magnetosonic waves in the heliospheric current sheet (HCS). The crossings of the HCS and the associated heliospheric plasma sheet (HPS) are encountered by Cluster in the near-Earth solar wind and by ACE upstream of Earth. Multiple current layers are detected in co…
Hubble Space Telescope imaging and spectroscopy of the sirius-like triple star system HD 217411
Bond, Howard E.; Barstow, M. A.; Holberg, J. B. +2 more
We present Hubble Space Telescope imaging and spectroscopy of HD 217411, a G3 V star associated with the extreme ultraviolet (UV) excess source (EUV 2RE J2300-07.0). This star is revealed to be a triple system with a G 3V primary (HD 217411 A) separated by ∼1.1 arcsec from a secondary that is in turn composed of an unresolved K0 V star (HD 21741…
Antimatter in the Universe: constraints from gamma-ray astronomy
von Ballmoos, Peter
We review gamma-ray observations that constrain antimatter - both baryonic and leptonic - in the Universe. Antimatter is probed through ordinary matter, with the resulting annihilation gamma-rays providing indirect evidence for its presence. Although it is generally accepted that equal amounts of matter and antimatter have been produced in the Big…
Modeling Active Region Transient Brightenings Observed with X-Ray Telescope as Multi-stranded Loops
McKenzie, David E.; Donachie, Martin; Kobelski, Adam R.
Strong evidence exists that coronal loops as observed in extreme ultraviolet and soft X-rays may not be monolithic isotropic structures, but can often be more accurately modeled as bundles of independent strands. Modeling the observed active region transient brightenings (ARTBs) within this framework allows for the exploration of the energetic ram…
Herschel SPIRE FTS telescope model correction
Valtchanov, Ivan; Hopwood, Rosalind; Lu, Nanyao +8 more
Emission from the Herschel telescope is the dominant source of radiation for the majority of SPIRE Fourier transform spectrometer (FTS) observations, despite the exceptionally low emissivity of the primary and secondary mirrors. Accurate modelling and removal of the telescope contribution is, therefore, an important and challenging aspect of FTS c…
Fe-rich Ejecta in the Supernova Remnant G352.7-0.1 with Suzaku
Sezer, A.; Gök, F.
In this work, we present results from a ~201.6 ks observation of G352.7-0.1 using the X-ray Imaging Spectrometer on board Suzaku X-ray Observatory. The X-ray emission from the remnant is well described by two-temperature thermal models of non-equilibrium ionization with variable abundances with a column density of N H ~ 3.3 × 1022<…
Earth occultation imaging of the low energy gamma-ray sky with GBM
Wilson-Hodge, C. A.; Camero-Arranz, A.; Rodi, J. +5 more
Aims: The Earth Occultation Technique (EOT) has been applied to Fermi's Gamma-ray Burst Monitor (GBM) to perform all-sky monitoring for a predetermined catalog of hard X-ray/soft γ-ray sources. In order to search for sources not in the catalog, thus completing the catalog and reducing a source of systematic error in EOT, an imaging method has…
The Role of Magnetic Fields in Transient Seismic Emission Driven by Atmospheric Heating in Flares
Lindsey, C.; Hudson, H. S.; Donea, A. -C. +1 more
Transient seismic emission in flares remains largely mysterious. Its discoverers proposed that seismic transients are driven by impulsive heating of the flaring chromosphere. Simulations of such heating show strong shocks, but these are damped by heavy radiative losses as they proceed downward. Because compression of the gas the shock enters both …
The orbit of transneptunian binary Manwë and Thorondor and their upcoming mutual events
Grundy, W. M.; Noll, K. S.; Benecchi, S. D. +1 more
A new Hubble Space Telescope observation of the 7:4 resonant transneptunian binary system (385446) Manwë has shown that, of two previously reported solutions for the orbit of its satellite Thorondor, the prograde one is correct. The orbit has a period of 110.18 ± 0.02 days, semimajor axis of 6670 ± 40 km, and an eccentricity of 0.563 ± 0.007. It w…
Eastern Olympus Mons Basal Scarp: Structural and mechanical evidence for large-scale slope instability
Weller, M. B.; McGovern, P. J.; Fournier, T. +1 more
The expression of the Eastern Olympus Mons Basal Scarp (EOMBS) is seemingly unique along the edifice. It exhibits two slope-parallel structures: a nearly 100 km long upslope extensional normal fault system and a downslope contractional wrinkle ridge network, a combination that is found nowhere else on Olympus Mons. Through structural mapping and n…