Search Publications
Vertical Dynamics of the Energy Release Process in a Simple two-Ribbon Flare
Warmuth, Alexander; Otruba, Wolfgang; Klein, Karl-Ludwig +2 more
Observations of the quiescent filament eruption and the spotless two-ribbon flare of 12 September 2000 are presented. A simple flare morphology, large spatial scales, and a suitable viewing angle provide insight into characteristics of the energy release process which is attributed to the reconnection process in the current sheet formed below the …
Probing the Size of Low-Redshift Lyα Absorbers
Stocke, John T.; Giroux, Mark L.; Ganguly, Rajib +1 more
The 3C 273 and RX J1230.8+0115 sight lines probe the outskirts of the Virgo Cluster at physical separations between the sight lines of 200 and 500 h-170 kpc. We present an analysis of available Hubble Space Telescope STIS echelle and Far-Ultraviolet Spectroscopic Explorer (FUSE) UV spectroscopy of RX J1230.8+0115, in which we…
Stellar Hydrodynamics in Radiative Regions
Rigby, Jane R.; Knierman, Karen A.; Young, Patrick A. +1 more
We present an analysis of the response of a radiative region to waves generated by a convective region of the star; this wave treatment of the classical problem of ``overshooting'' gives extra mixing relative to the treatment traditionally used in stellar evolutionary codes. The interface between convectively stable and unstable regions is dynamic…
SPI measurements of Galactic 26Al
Strong, A. W.; Knödlseder, J.; von Kienlin, A. +8 more
The precision measurement of the 1809 keV gamma-ray line from Galactic 26Al is one of the goals of the SPI spectrometer on INTEGRAL with its Ge detector camera. We aim for determination of the detailed shape of this gamma-ray line, and its variation for different source regions along the plane of the Galaxy. Data from the first part of …
Cluster four spacecraft measurements of small traveling compression regions in the near-tail
Balogh, A.; Lucek, E.; Owen, C. J. +11 more
Cluster observations taken during a substorm on September 19, 2001 have revealed the presence of small traveling compression regions (TCRs) in the near tail. These measurements are used to determine directly the speed and direction of TCR propagation and the amplitude of the underlying bulge in the plasma sheet. The time-of-flight speeds derived f…
XMM-Newton X-ray observations of the Carina nebula
Méndez, M.; Morrell, N. I.; Albacete Colombo, J. F.
We use new XMM-Newton observations to perform a detailed X-ray analysis of the Carina nebula region in the 0.3-12 keV energy range. Our source detection yields 80 discrete X-ray sources, from which about 20 per cent seem not to have optical counterparts. To get an idea of the energy spectrum of these sources, we construct an X-ray colour-colour di…
Ion cyclotron waves in the high altitude cusp: CLUSTER observations at varying spacecraft separations
Balogh, A.; Dandouras, I.; Lavraud, B. +5 more
We have analysed high-resolution Cluster magnetic field data during three high-altitude cusp crossings in 2001 and 2002. The Cluster separations for these crossings varied between 100 and 600 km and therefore provided an unique opportunity to study wave properties at different length scales. In the cusp Cluster sees frequent intervals of magnetic …
The open cluster distance scale. A new empirical approach
Salaris, M.; Kilkenny, D.; Percival, S. M.
We present new BV(RI)C photometry for a sample of 54 local G and K stars with accurate Hipparcos parallaxes in the metallicity range -0.4 <= [Fe/H] <= +0.3. We use this sample to develop a completely model-independent main sequence (MS) fitting method which we apply to 4 open clusters - the Hyades, Praesepe, the Pleiades and NGC 2…
The Crab pulsar and its red knot in the near-infrared
Sollerman, J.
We present near-infrared observations obtained with ISAAC on the VLT of the Crab pulsar and its environment. Photometry of the pulsar in Js, H and Ks shows the pulsar spectrum to extend fairly smoothly from the UV/optical regime. PSF subtraction of the pulsar allows us to study its immediate neighborhood in some detail. In pa…
XMM-Newton observations of the Seyfert 1 galaxy NGC 3227
Gondoin, P.; Orr, A.; Lumb, D. +1 more
We report on an XMM-Newton observation of the Seyfert 1 galaxy NGC 3227 performed in November 2000. The observed X-ray spectrum above 4 keV is well fitted by a hard power law continuum (Gamma ~ 1.5) and an absorption edge at 7.6 keV. An Fe K emission line with an equivalent width of 213 eV is detected at 6.4 keV. The line is narrow suggesting cont…