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In situ multi-satellite detection of coherent vortices as a manifestation of Alfvénic turbulence
Sundkvist, David; Vaivads, Andris; Krasnoselskikh, Vladimir +4 more
Turbulence in fluids and plasmas is a ubiquitous phenomenon driven by a variety of sources-currents, sheared flows, gradients in density and temperature, and so on. Turbulence involves fluctuations of physical properties on many different scales, which interact nonlinearly to produce self-organized structures in the form of vortices. Vortex motion…
Helioseismic Determination of the Solar Rotation Axis
Giles, P.; Beck, J. G.
Time-distance helioseismology analysis of Dopplergrams from the Michelson Doppler Imager instrument on board the Solar and Heliospheric Observatory spacecraft provides a very accurate measurement of meridional flows. This shows a sinusoidal variation with a period of 1 yr and was identified by P. Giles to be due to an error in the determination of…
Unstable relics as a source of galactic positrons
Pospelov, Maxim; Picciotto, Charles
We calculate the fluxes of 511 keV photons from the galactic bulge caused by positrons produced in the decays of relic particles with masses less than 100 MeV. In particular, we tighten the constraints on sterile neutrinos over a large domain of the mass-mixing angle parameter space, where the resulting photon flux would significantly exceed the e…
The Evolution of Reconnection along an Arcade of Magnetic Loops
Benz, Arnold O.; Grigis, Paolo C.
RHESSI observations of a solar flare showing continuous motions of double hard X-ray sources interpreted as footpoints of magnetic loops are presented. The temporal evolution shows many distinct emission peaks of duration of some tens of seconds (``elementary flare bursts''). Elementary flare bursts have been interpreted as instabilities or oscill…
The evolution of the galaxy B-band rest-frame morphology to z~ 2: new clues from the K20/GOODS sample
Cimatti, A.; Daddi, E.; Rodighiero, G. +7 more
We present a detailed analysis of the evolution of the rest-frame B-band morphology of K-selected galaxies with 0 < z < 2.5. This work is based on the K20 spectroscopic sample (Ks < 20) located within the Chandra Deep Field South area, coupled with the public deep GOODS (Great Observatories Origins Deep Surveys) Hubble Space Telescope (HS…
INTEGRAL and RXTE observations of accreting millisecond pulsar IGR J00291+5934 in outburst
Goldoni, P.; Stella, L.; Kuiper, L. +7 more
Simultaneous observations of the accretion-powered millisecond pulsar IGR J00291+5934 by the International Gamma-Ray Astrophysics Laboratory and Rossi X-ray Timing Explorer during the 2004 December outburst are analysed. The average spectrum is well described by thermal Comptonization with an electron temperature of 50 keV and Thomson optical dept…
Evidence for rotationally driven plasma transport in Saturn's magnetosphere
André, N.; Lewis, G. R.; Coates, A. J. +7 more
Radial convective transport of plasma in a rotation-dominated magnetosphere implies alternating longitudinal sectors of cooler, denser plasma moving outward and hotter, more tenuous plasma moving inward. The Cassini Plasma Spectrometer (CAPS) has provided dramatic new evidence of this process operating in the magnetosphere of Saturn. The inward tr…
Nucleus properties of Comet 67P/Churyumov Gerasimenko estimated from non-gravitational force modeling
Gutiérrez, Pedro J.; Davidsson, Björn J. R.
By considering model comet nuclei with a wide range of sizes, prolate ellipsoidal shapes, spin axis orientations, and surface activity patterns, constraints have been placed on the nucleus properties of the primary Rosetta target, Comet 67P/Churyumov-Gerasimenko. This is done by requiring that the model bodies simultaneously reproduce the empirica…
The First Giant Flare from SGR 1806-20: Observations Using the Anticoincidence Shield of the Spectrometer on INTEGRAL
Götz, D.; Mereghetti, S.; von Kienlin, A. +4 more
A giant flare from the soft gamma-ray repeater SGR 1806-20 has been discovered with the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) on 2004 December 27 and detected by many other satellites. This tremendous outburst, the first one observed from this source, was a hundred times more powerful than the two giant flares previously obser…
The Near-Infrared Camera and Multi-Object Spectrometer Ultra Deep Field: Observations, Data Reduction, and Galaxy Photometry
Dickinson, Mark; Franx, Marijn; van Dokkum, Pieter +10 more
This paper describes the observations and data reduction techniques for the version 2.0 images and catalog of the Near-Infrared Camera and Multi-Object Spectrometer Ultra Deep Field (NICMOS UDF) Treasury program. All sources discussed in this paper are based on detections in the combined NICMOS F110W and F160W bands only. The NICMOS images are dri…