Search Publications
Signatures of transition region explosive events in hydrogen Lyβ profiles
Chen, Y.; Tian, H.; Zhang, M. +1 more
Aims: We search for signatures of transition region explosive events (EEs) in hydrogen Lyβ profiles. The relationship between the peak emission of Lyβ profiles and the wing emission of C ii and O vi during EEs is investigated.
Methods: Two rasters made by the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) instrument onboard …
Solar phase curves and phase integrals for the leading and trailing hemispheres of Iapetus from the Cassini Visual Infrared Mapping Spectrometer
Buratti, Bonnie J.; Mosher, Joel A.; Blackburn, David G. +1 more
We performed photometry of Cassini Visual Infrared Mapping Spectrometer observations of Iapetus to produce the first phase integrals calculated directly from solar phase curves of Iapetus for the leading hemisphere and to estimate the phase integrals for the trailing hemisphere. We also explored the phase integral dependence on wavelength and geom…
Composition Of The Inner Source Measured With The Solar Wind Ion Composition Spectrometer On Ulysses
Geiss, J.; Gloeckler, G.; Fisk, L. A.
To explain the unexpected discovery of C+, the existence of an inner source of pickup ions close to the Sun was proposed. We report on detailed analyses of the composition and the radial and latitudinal variations of inner source pickup ions measured with the Solar Wind Ion Composition Spectrometer on Ulysses from 1991 to 1998, approach…
Current Sheet in a non-Maxwellian collisionless plasma: Self-consistent theory, simulation, and comparison with spacecraft observations
Popov, V. Yu.; Petrukovich, A. A.; Zelenyi, L. M. +4 more
A self-consistent theory is constructed of anisotropic current equilibria maintained in a non-Maxwellian plasma consisting of cold electrons and two hot ion components of different temperatures. The ion plasma components are described in the quasi-adiabatic approximation, and the plasma electrons, in the MHD approximation. Approximate steady solut…
The z = 0.0777 CIII absorber towards PHL 1811 as a case study of a low-redshift weak metal line absorber
Charlton, J. C.; Lacki, B. C.
We consider the physical conditions and origin of the z = 0.0777 absorption system observed in CIII, CII, SiIII, CIV, OVI and HI absorption along the line of sight towards the quasar PHL 1811. We analysed the Hubble Space Telescope/Space Telescope Imaging Spectrograph and Far Ultraviolet Spectroscopic Explorer spectra of this quasar and compared t…
Determining the morpho-kinematic properties of a face-on merger at z ~ 0.7
Yang, Y.; Flores, H.; Hammer, F. +4 more
Context. At intermediate redshifts, many galaxies seem to have experienced an interaction. It is not always straightforward to determine what type of encounter or perturbation is observed, nor the outcome of this event. In some cases, only the use of both morphological and kinematical information can determine the true configuration of an encounte…
Some ring-shaped potentials as a generalized 4-D isotropic oscillator. Periodic orbits
Tresaco, Eva; Ferrer, Sebastián
A generalized integrable biparametric family of 4-D isotropic oscillators is proposed. It allows to treat in a unified way, Pöschl-Teller, Hartmann and other ring-shaped systems. This approach, based in the use of two canonical extensions, helps to simplify the studies of classical aspects of those systems. As an illustration, an analysis of the p…
Chemical composition of simulated Titan's midatmospheric aerosols
Bar-Nun, A.; Dimitrov, V.; Jacovi, R. +1 more
A large fraction of the major unsaturated species (C2H2 C2H4, HCN, and HC3N) with mixing ratios of about 3 × 10-6, 10-7-10-8, 3 × 10-7, and 10-9-10-10 reside in Titan's atmosphere between 150 and 500 km (Vinatier et al., 2009; C…
Space radiation environment effects on X-ray CCD background
Hall, David J.; Holland, Andrew
Charge coupled devices (CCDs) are often employed as the detector of choice for observing X-rays in space. The instrument background experienced in orbit has a major impact on the overall sensitivity of the camera system. The instrument background for the European Space Agency X-ray Multi Mirror (XMM-Newton) mission was found to be much greater in …
A Kinematical Study of the Galaxy Based on the Revised Hipparcos Astrometric Data
Shen, Ming; Zhang, Hong
On the basis of the revised Hipparcos data recently released, the zero-point of the period-luminosity relation for classical cepheids is reexamined. Fitting the proper motion and radial velocity data via an axisymmetric model, the Oort constants and circular rotation velocity of the LSR are calculated to obtain the Galactocentric distance of the S…