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Arakelian 564: an XMM-Newton view
Brandt, W. N.; Fabian, A. C.; Boller, Th. +2 more
We report on two XMM-Newton observations of the bright narrow-line Seyfert 1 galaxy Ark 564 taken 1 yr apart (2000 June and 2001 June). The 0.6-10 keV continuum is well described by a soft blackbody component (kT~ 140-150 eV) plus a steep power law (Γ~ 2.50-2.55). No significant spectral changes are observed between the two observations, although …
Asiago eclipsing binaries program. I. V432 Aurigae
Munari, U.; Zwitter, T.; Sordo, R. +4 more
The orbit and physical parameters of the previously unsolved eclipsing binary V432 Aur, discovered by Hipparcos, have been derived with errors better than 1% from extensive Echelle spectroscopy and B, V photometry. Synthetic spectral analysis of both components has been performed, yielding Teff and log g in close agreement with the orbi…
INTEGRAL Field Spectroscopy of the Extended Ionized Gas in Arp 220
Arribas, Santiago; Colina, Luis; Clements, David
Integral field optical spectroscopy with the INTEGRAL system has been used to investigate for the first time the two-dimensional kinematic and ionization properties of the extended, warm, ionized gas in Arp 220 over an area of 75.0"×40.0" (i.e., 28×15 kpc). The structure of the ionized gas is divided into well-identified regions associated with th…
The morphology of cometary X-ray emission
Dennerl, K.; Wegmann, R.; Lisse, C. M.
X-ray emission from comets is generated by charge exchange of heavy solar wind ions in a high ionization state with the neutral particles of the cometary coma. We use model calculations and theoretical considerations to study the morphology of the emission. The emission is located in a bowl-shaped region on the subsolar side of the nucleus. We der…
CASSINI/VIMS-V at Jupiter: Radiometric calibration test and data results
Brown, R. H.; Gondet, B.; Langevin, Y. +5 more
During the Cassini-Huygens flyby of Jupiter in December 2000, VIMS-V acquired multispectral data cubes of Jupiter's atmosphere. The visual and infrared imaging spectrometer-visual channel (VIMS-V) is one of the principal contributions of Italian Space Agency (ASI) to the Cassini-Huygens mission to Saturn. VIMS-V is an imaging spectrometer operatin…
Cluster measurements of rapidly moving sources of ELF/VLF chorus
Gurnett, D. A.; Pickett, J. S.; Inan, U. S. +2 more
The first simultaneous measurements of discrete chorus emissions on multiple spacecraft, realized in the context of the Cluster mission, revealed a rather unexpected frequency difference of around 1 kHz between nearly identical discrete elements observed on different spacecraft [, 2001]. This frequency difference is interpreted herein as a natural…
Effect of the electron density stratification on off-limb O VI line profiles: How large is the velocity distribution anisotropy in the solar corona?
Solanki, S. K.; Raouafi, N. -E.
Coronagraphic spectral observations carried out with UVCS on SoHO have shown that the velocity distribution in the solar corona is highly anisotropic. Here we examine the influence of the density stratification on the interpretation of such observations. In particular, we investigate the profiles of O VI lines emitted in the corona by employing an…
Neutral hydrogen gas in interacting galaxies: the NGC 6221/6215 galaxy group
Koribalski, Bärbel; Dickey, John M.
Neutral hydrogen observations of the spiral galaxies NGC 6221 and 6215 with the Australia Telescope Compact Array (ATCA) reveal a wide, two-stranded bridge of at least 3 × 108 Msolar which can be traced between the two galaxies over a projected distance of 100 kpc. The velocity gradient of the HI bridge provides a rough estim…
Solar Energetic Particle Acceleration in Refracting Coronal Shock Waves
Vainio, Rami; Khan, Josef I.
Gradual solar energetic particle (SEP) events are known to be correlated with coronal mass ejections (CMEs) and soft X-ray flares. The current paradigm of particle acceleration in these events attributes it to CME-driven shock waves in the solar corona and in interplanetary space. Even in small gradual SEP events related to CMEs with speeds in the…
CLUSTER encounters with the high altitude cusp: boundary structure and magnetic field depletions
Balogh, A.; Dandouras, I.; Lavraud, B. +6 more
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