Search Publications
On the structure of polar faculae on the Sun
Okunev, O. V.; Kneer, F.
Faculae on the polar caps of the Sun, in short polar faculae (PFe), are investigated. They take part in the magnetic solar cycle. Here, we study the fine structures of PFe, their magnetic fields and their dynamics on short time scales. The observations stem from several periods in 2001 and 2002. They consist of spectropolarimetric data (Stokes I a…
The Nitrogen Isotopic Ratio in Jupiter's Atmosphere from Observations by the Composite Infrared Spectrometer on the Cassini Spacecraft
Flasar, F. M.; Owen, T.; Achterberg, R. K. +9 more
The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft made infrared observations of Jupiter's atmosphere during the flyby of 2000 December to 2001 January. The unique database in the 600-1400 cm-1 region with 0.53 and 2.8 cm-1 spectral resolutions obtained from the observations permits retrieval of global maps …
A Reexamination of the Evidence for Reconnection Inflow
Chen, P. F.; Brooks, D. H.; Shibata, K. +1 more
In the flare event of 1999 March 18, a threadlike structure observed in EUV Imaging Telescope images was found to move inward and collapse to an X-shaped configuration below the ejecta, strongly suggestive of the occurrence of magnetic reconnection. On the basis of the numerical results of a coronal mass ejection (CME) flare model, a similar threa…
Solitary structures associated with short large-amplitude magnetic structures (SLAMS) upstream of the Earth's quasi-parallel bow shock
Balogh, A.; Pickett, J. S.; André, M. +4 more
For the first time, solitary waves (SWs) have been observed within short large-amplitude magnetic structures (SLAMS) upstream of the Earth's quasi-parallel bow shock. The SWs often occur as bipolar pulses in the electric field data and move parallel to the background magnetic field at velocities of v = 400-1200 km/s. They have peak-to-peak amplitu…
XMM-Newton observations of GB B1428+4217: confirmation of intrinsic soft X-ray absorption
Iwasawa, K.; Fabian, A. C.; Celotti, A. +1 more
We report the results of XMM-Newton observations of the X-ray bright, radio-loud blazar GB B1428+4217 at a redshift of z= 4.72. We confirm the presence of soft X-ray spectral flattening at energies <~0.7 keV as reported in previous ROSAT and BeppoSAX observations. At hard X-ray energies, the spectrum is consistent with a power law, although we …
65 Cybele in the thermal infrared: Multiple observations and thermophysical analysis
Blommaert, J. A. D. L.; Müller, T. G.
We investigated the physical and thermal properties of
Variability of solar eruptions during cycle 23
Howard, R. A.; Gopalswamy, N.; Yashiro, S. +1 more
We report on the solar cycle variation of the rate of coronal mass ejections (CMEs), their mean and median speeds, and the rate of type II radio bursts. We found that both CME rate and speed (mean and median) increased from solar minimum to maximum by factors of 10 and 2, respectively. The CME rate during solar maximum is nearly twice the rates qu…
Magnetic Footpoint Diffusion at the Sun and Its Relation to the Heliospheric Magnetic Field
Giacalone, J.; Jokipii, J. R.
We discuss the physics associated with the motion of the radial magnetic field footpoints at the Sun and its relation to the heliospheric magnetic field. Using the observed photospheric convection spectrum, we construct a model for the heliospheric magnetic field and relate it to observations made by Ulysses in the outer heliosphere in the fast so…
The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda II
Da Costa, G. S.; Pritzl, Barton J.; Armandroff, Taft E. +1 more
We present the results of a variable star search in Andromeda II, a dwarf spheroidal galaxy companion to M31, using Hubble Space Telescope Wide Field Planetary Camera 2 observations. Seventy-three variables were found, one of which is an anomalous Cepheid while the others are RR Lyrae stars. The anomalous Cepheid has properties consistent with tho…
XMM-Newton observations of high-luminosity radio-quiet quasi-stellar objects
O'Brien, P. T.; Worrall, D. M.; Reeves, J. N. +2 more
XMM-Newton observations of five high-luminosity radio-quiet quasi-stellar objects (QSOs; Q 0144-3938, UM 269, PG 1634+706, SBS 0909+532 and PG 1247+267) are presented. Spectral energy distributions were calculated from the XMM-Newton European Photon Imaging Camera (EPIC) and Optical Monitor (OM) data, with bolometric luminosities estimated in the …