Search Publications
Dust attenuation in galaxies up to redshift ≃ 2
Buat, V.
We want to study dust attenuation at ultraviolet (UV) wavelengths at high redshift, where the UV is redshifted to the observed visible light wavelength range. In particular, we search for a bump at 2175 Å. We use photometric data in the Chandra Deep Field South (CDFS), obtained in intermediate and broad band filters by the MUSYC project, to sample…
Doppler shift and broadening in solar wind turbulence
Glassmeier, K. -H.; Narita, Y.; Motschmann, U. +1 more
We propose a method to evaluate the Doppler shift and broadening using magnetic field data in solar wind turbulence. A model of the energy spectrum is constructed in the wavenumber-frequency domain in the direction of the mean flow, and it is compared with that determined directly from four-point magnetic field data of Cluster spacecraft using the…
Infrared composition of the Large Magellanic Cloud
Takeuchi, T. T.; Onaka, T.; Ita, Y. +3 more
The evolution of galaxies and the history of star formation in the Universe are among the most important topics in today's astrophysics. Especially, the role of small, irregular galaxies in the star-formation history of the Universe is not yet clear. Using the data from the AKARI IRC survey of the Large Magellanic Cloud at 3.2, 7, 11, 15, and 24 &…
Ion distributions in the vicinity of Mars: Signatures of heating and acceleration processes
Fedorov, A.; Barabash, S.; Lundin, R. +5 more
More than three years of data from the ASPERA-3 instrument on-board Mars Express has been used to compile average distribution functions of ions in and around the Mars induced magnetosphere. We present samples of average distribution functions, as well as average flux patterns based on the average distribution functions, all suitable for detailed …
Control of ion loss from Mars during solar minimum
Brecht, Stephen H.; Ledvina, Stephen A.
A hybrid particle code has been used to examine the interaction of the solar wind with Mars during solar minimum. The results were surprising as they produced ion loss rates from Mars far in excess of what is estimated from MEX. The results are analyzed and found to be consistent with the competition between photochemical rates and advection of th…
The orientation of Titan's dayside ionosphere and its effects on Titan's plasma interaction
Brecht, Stephen H.; Ledvina, Stephen A.; Cravens, Thomas E.
A hybrid particle code has been used to examine how Titan's interaction with Saturn's magnetosphere is effected by the orientation of the dayside ionosphere with respect to the incident magnetospheric flow. The hybrid code self-consistently includes a version of Titan's ionosphere represented by 7 generic ion species, over 40 ionneutral chemical r…
Upper ionosphere of Mars is not axially symmetrical
Gurnett, D. A.; Barabash, S.; Lundin, R. +6 more
The measurements carried out by the ASPERA-3 and MARSIS experiments on board the Mars Express (MEX) spacecraft show that the upper Martian ionosphere (h ≥ 400 km) is strongly azimuthally asymmetrical. There are several factors, e.g., the crustal magnetization on Mars and the orientation of the interplanetary magnetic field (IMF) which c…
Ion acceleration by multiple reflections at Martian bow shock
Fedorov, A.; Barabash, S.; Lundin, R. +7 more
The ion mass analyzer (IMA) on board Mars Express revealed bundled structures of ions in the energy domain within a distance of a proton gyroradius from the Martian bow shock. Seven prominent traversals during 2005 were examined when the energy-bunched structure was observed together with pick-up ions of exospheric origin, the latter of which is u…
Ionogram inversion for MARSIS topside sounding
Wan, Weixing; Han, Xiuhong
In the present paper, we propose a method of ionogram inversion to retrieve the electron density profile, Ne(h), of the Martian ionosphere from the topside ionogram, which is measured by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board the Mars Express spacecraft. The new inversion technique is…
Sublimation temperature of circumstellar dust particles and its importance for dust ring formation
Kimura, Hiroshi; Müller, Sebastian; Kobayashi, Hiroshi +2 more
Dust particles in orbit around a star drift toward the central star by the Poynting-Robertson effect and pile up by sublimation. We analytically derive the pile-up magnitude, adopting a simple model for optical cross sections. As a result, we find that the sublimation temperature of drifting dust particles plays the most important role in the pile…