Search Publications
Can the Excess in the Fe XXVI Lyγ Line from the Galactic Center Provide Evidence for 17 keV Sterile Neutrinos?
Silk, Joseph; Prokhorov, Dmitry
Sterile neutrinos (or right-handed neutrinos) are a plausible warm dark matter candidate. We find that the excess of the intensity in the 8.7 keV line (at the energy of the Fe XXVI Lyγ line) in the spectrum of the Galactic center observed by Suzaku cannot be explained by standard ionization and recombination processes. We suggest that the origin o…
Herschel observations of EXtra-Ordinary Sources (HEXOS): Observations of H2O and its isotopologues towards Orion KL
Menten, K. M.; Falgarone, E.; Martin, P. G. +49 more
We report the detection of more than 48 velocity-resolved ground rotational state transitions of H_216O, H_218O, and H_217O - most for the first time - in both emission and absorption toward Orion KL using Herschel/HIFI. We show that a simple fit, constrained to match the known emission and absorption components al…
A Flux Rope Eruption Triggered by Jets
Guo, Juan; Zhang, Hongqi; Liu, Yu +3 more
We present an observation of a filament eruption caused by recurrent chromospheric plasma injections (surges/jets) on 2006 July 6. The filament eruption was associated with an M2.5 two-ribbon flare and a coronal mass ejection (CME). There was a light bridge in the umbra of the main sunspot of NOAA 10898; one end of the filament was terminated at t…
Nonlinear Force-free Modeling of Magnetic Fields in a Solar Filament
Xu, Yan; Jing, Ju; Wang, Haimin +3 more
We present a striking filament pattern in the nonlinear force-free (NLFF) chromospheric magnetic field of the active region NOAA 10956. The NLFF chromospheric field is extrapolated from the Hinode high-resolution photospheric vector magnetogram using the weighted optimization method. The modeled structure is characterized by a highly sheared field…
Hipparcos preliminary astrometric masses for the two close-in companions to HD 131664 and HD 43848. A brown dwarf and a low-mass star
Sozzetti, A.; Desidera, S.
Context. Several mechanisms for forming brown dwarfs have been proposed, which today are not believed to be mutually exclusive. Among the fundamental characteristics of brown dwarfs that are intrinsically tied to their origins, multiplicity is particularly relevant. Any successful determination of the actual mass for such objects in any systems is…
Testing Accretion Disk Structure with Suzaku Data of LMC X-3
Done, Chris; Dotani, Tadayasu; Ueda, Yoshihiro +3 more
The Suzaku observation of LMC X-3 gives the best data to date on the shape of the accretion disk spectrum. This is due to the combination of very low absorbing column density along this line of sight, which allows the shape of the disk emission to be constrained at low energies by the CCDs while the tail can be simultaneously determined up to 30 k…
Characteristics of ground-level enhancement-associated solar flares, coronal mass ejections, and solar energetic particles
Cho, K. -S.; Firoz, K. A.; Hwang, J. +7 more
Ground-level enhancements (GLEs) are sudden, sharp, and short-lived increases in cosmic ray intensities registered by neutron monitors. These enhancements are known to take place during powerful solar eruptions. In the present investigation, the cosmic ray intensities registered by the Oulu neutron monitor have been studied for the period between …
Self-gravity wake parameters in Saturn’s A and B rings
Nicholson, P. D.; Hedman, M. M.
An increasing body of evidence shows that, at the sub-km level, Saturn's main A and B rings are dominated by an ever-changing pattern of elongated, canted structures known as self-gravity wakes. Best known for causing azimuthal variations in the rings' reflectivity, these structures also have a profound influence on how the transmission of the rin…
XMM-Newton and SUZAKU detection of an X-ray emitting shell around the pulsar wind nebula G54.1+0.3
Bocchino, F.; Bandiera, R.; Gelfand, J.
Context. X-ray observations have proven to be very effective in detecting previously unknown supernova remnant shells around pulsar wind nebulae (PWNe), and in these cases the characteristics of the shell provide information about the evolutionary stage of the embedded PWN. However, it is not clear why some PWNe are “naked”.
Aims: We perform …
Solar Rotation Rate During the Cycle 24 Minimum in Activity
Basu, Sarbani; Antia, H. M.
The minimum of solar cycle 24 is significantly different from most other minima in terms of its duration as well as its abnormally low levels of activity. Using available helioseismic data that cover epochs from the minimum of cycle 23 to now, we study the differences in the nature of the solar rotation between the minima of cycles 23 and 24. We f…