Search Publications
Ion cyclotron waves during the Rosetta approach phase: a magnetic estimate of cometary outgassing
Glassmeier, K. -H.; Volwerk, M.; Richter, I. +4 more
A theoretical model for the ion cyclotron wave generation during the approach phase of Rosetta to 67P/Churyumov-Gerasimenko is presented. For various activity levels of the comet, the crossing of the observational threshold is determined, whose level is derived from the wave power in the undisturbed solar wind near the comet's location during the …
Inflation in the generalized inverse power law scenario
Lu, Zhun
We propose a single field inflationary model by generalizing the inverse power law potential from the intermediate model. We study the implication of our model on the primordial anisotropy of cosmological microwave background radiation. Specifically, we apply the slow-roll approximation to calculate the scalar spectral tilt ns and the t…
Polar plumes' orientation and the Sun's global magnetic field
Inhester, Bernd; de Patoul, Judith; Cameron, Robert
Aims: We characterize the orientation of polar plumes as a tracer of the large-scale coronal magnetic field configuration. We monitor in particular the north and south magnetic pole locations and the magnetic opening during 2007-2008 and provide some understanding of the variations in these quantities.
Methods: The polar plume orientatio…
Gravitationally lensed extended sources: the case of QSO RXJ0911
Diep, Pham Ngoc; Nhung, Pham Tuyet; Hoai, Do Thi +6 more
After a brief reminder of the mechanism of gravitational lensing of extended sources, the particular case of the host galaxy of QSO RXJ0911, a high redshift (z ~ 2.8) quadruply imaged quasar, is explored. The non linearity of the problem, together with the proximity of the source to a cusp of the lens inner caustic, has important consequences on t…
Three-dimensional multi-fluid simulations of Titan's interaction with Saturn's magnetosphere: Comparisons with Cassini's T55 flyby
Snowden, D.; Winglee, R.
We describe a new multi-fluid model of Titan's interaction with Saturn's magnetosphere that includes finer resolution in Titan's ionosphere, photoionization, electron-impact ionization, dissociative recombination, and ion-neutral coupling in the momentum and energy equations. We compare simulation results to data from Cassini's T55 flyby to show t…
Discovery of a Large Population of Ultraluminous X-Ray Sources in the Bulgeless Galaxies NGC 337 and ESO 501-23
Mathur, Smita; Martini, Paul; Somers, Garrett +3 more
We have used Chandra observations of eight bulgeless disk galaxies to identify new ultraluminous X-ray source (ULX) candidates, study their high-mass X-ray binary (HMXB) population, and search for low-luminosity active galactic nuclei (AGNs). We report the discovery of 16 new ULX candidates in our sample of galaxies. Eight of these are found in th…
Vertical Relaxation of a Moonlet Propeller in Saturn's A Ring
Seiß, M.; Spahn, F.; Hoffmann, H.
Two images, taken by the Cassini spacecraft near Saturn's equinox in 2009 August, show the Earhart propeller casting a 350 km long shadow, offering the opportunity to watch how the ring height, excited by the propeller moonlet, relaxes to an equilibrium state. From the shape of the shadow cast and a model of the azimuthal propeller height relaxati…
Using an Ellipsoid Model to Track and Predict the Evolution and Propagation of Coronal Mass Ejections
Cattell, C.; Schreiner, S.; Kersten, K. +1 more
We present a method for tracking and predicting the propagation and evolution of coronal mass ejections (CMEs) using the imagers on the STEREO and SOHO satellites. By empirically modeling the material between the inner core and leading edge of a CME as an expanding, outward propagating ellipsoid, we track its evolution in three-dimensional space. …
Stars with discrepant v sin i as derived from the Ca II λ3933 Å and Mg II λ4481 Å lines. IV. HD8837—a shell star, HD47964 and HD183986—new binaries
Stateva, I.; Semenko, E.; Kudryavtsev, D. +4 more
Axial rotation of a star plays an important role in its evolution, physical conditions in its atmosphere, and appearance of its spectrum. We have analyzed CCD spectra of three stars for which their projected rotational velocity remarkably differs when derived from the Ca II λ 3933 Å and MgII λ 4481 Å lines. We derived effective temperatures and su…
X-ray and multiwavelength insights into the inner structure of high-luminosity disc-like emitters
Brandt, W. N.; Wu, Jian; Luo, B. +5 more
We present X-ray and multiwavelength studies of a sample of eight high-luminosity active galactic nuclei (AGN) with disc-like Hβ emission-line profiles selected from the Sloan Digital Sky Survey Data Release 7. These sources have higher redshift (z ≈ 0.6) than the majority of the known disc-like emitters, and they occupy a largely unexplored space…