Search Publications
Signatures of Magnetic Stress Prior to Three Solar Flares Observed by RHESSI
Longcope, Dana; McLinden, Emily; des Jardins, Angela +2 more
We examine the hard X-ray (HXR) footpoint sources of three flares, as observed by RHESSI, in combination with the topology given by the extrapolation of line-of-sight magnetograms into the corona. Assuming the HXR footpoint sources are chromospheric consequences of magnetic reconnection that takes place on separators, we further assume a relations…
Modulation of NTC frequencies by Pc5 ULF pulsations: Experimental test of the generation mechanism and magnetoseismology of the emitting surface
Grimald, S.; Foullon, C.; Décréau, P. M. E. +3 more
Nonthermal continuum (NTC) radiation is believed to be emitted by the conversion of an electrostatic wave into an electromagnetic one, which takes place at the Earth's magnetic equator. It is generally accepted that the frequency of the electrostatic wave at the source meets a local characteristic frequency placed in between two multiples of the e…
Astrometric measurement techniques
Reffert, Sabine
This contribution reviews the various principles which form the basis of astrometric measurements, such as meridian circle observations, imaging techniques, scanning satellites and interferometry. Various projects which employ those techniques are described, e.g. the Multichannel Astrometric Photometer, the Fine Guidance Sensors onboard the Hubble…
Simultaneous observations of the Martian atmosphere by Planetary Fourier Spectrometer on Mars Express and Miniature Thermal Emission Spectrometer on Mars Exploration Rover
Smith, M.; Grassi, D.; Formisano, V. +3 more
In this study we present temperature profiles in the lower atmosphere of Mars from simultaneous observations performed by the Planetary Fourier Spectrometer (PFS) aboard the Mars Express spacecraft and the Miniature Thermal Emission Spectrometer (Mini-TES) aboard the Mars Exploration Rovers. Thermal infrared spectra were collected in both the upwa…
Properties of Field Aligned Current in Plasma Sheet Boundary Layers in Magnetotail: Cluster Observation
Dunlop, M.; Liu, Zhen-Xing; Shi, Jian-Kui +2 more
Field aligned current (FAC) distribution in the plasma sheet boundary layers (PSBLs) in the magnetotail is studied statistically by analysing magnetic field data from the Cluster 4-point measurements. The results show that the FAC distribution on the dusk side is not the same as that on the dawn side in the magnetotail. On the each side earthward …
Formation of lower-hybrid solitary structures by modulational interaction between lower-hybrid and dispersive Alfvén waves
André, M.; Stenberg, G.; Eriksson, A. I. +1 more
We investigate the possibility that lower-hybrid solitary structures (LHSS), which are frequently observed in the Earth's ionosphere and magnetosphere, are formed as a result of a modulational interaction between lower-hybrid and dispersive Alfvén waves of initially small amplitude. A large amplitude lower-hybrid pump wave can excite density struc…
Cluster multispacecraft measurement of spatial scales of foreshock Langmuir waves
Pickett, J. S.; Dudok de Wit, T.; Santolik, O. +1 more
In this article, we present the first multispacecraft study of spatial scales of Langmuir wave packets in the terrestrial foreshock. We used data from the Wideband Data (WBD) instrument on the Cluster satellites to identify simultaneous observations of the same wave packet on multiple spacecraft at very small separations. To overcome instrumental …
Smooth, undisturbed dwarf spheroidal galaxies in the Perseus cluster core: Implications for dark matter content
Held, E. V.; Conselice, C. J.; De Rijcke, S. +1 more
Using deep HST/ACS observations of the core of the Perseus Cluster, we identify a large population of dwarf elliptical galaxies down to MV = -12. All these dwarfs are remarkably smooth in appearance, showing no evidence for internal features that could be the result of tidal processes or star formation induced by the cluster potential. …
Seismic Detection of Solar Mesogranular-Scale Flow
Woodard, M. F.
Helioseismic correlation data computed from the Solar and Heliospheric Observatory/Michelson Doppler Imager high-resolution Doppler images were inverted for solar flows of horizontal scale between 5 and 45 Mm. The photospheric Doppler velocity inferred from the inversions was compared with the original Doppler images at each scale. For horizontal …
The new star forming site NGC 6334 IV (MM3)
Roth, M.; Gómez, M.; Persi, P. +1 more
Aims: The eastern part of the massive star forming region NGC 6334 IV is characterized by the presence of the millimeter continuum sources MM3, MM4, and the optically thin HII region G351.24+0.65. Here we study the star formation in this part of the cloud.
Methods: We imaged this region, here named NGC 6334 IV (MM3), at sub-arcsec resolution i…