Search Publications
Recovering the star formation rate in the solar neighborhood
Prada Moroni, P. G.; Degl'Innocenti, S.; Cignoni, M. +1 more
Aims.This paper develops a method for obtaining the star formation histories of a mixed, resolved population through the use of color-magnitude diagrams (CMDs). The method provides insight into the local star formation rate, analyzing the observations of the Hipparcos satellite through a comparison with synthetic CMDs computed for different histor…
The O VII X-Ray Forest toward Markarian 421: Consistency between XMM-Newton and Chandra
Kaastra, J. S.; de Plaa, J.; de Vries, C. P. +4 more
Recently, the first detections of highly ionized gas associated with two warm-hot intergalactic medium (WHIM) filaments have been reported. The evidence is based on X-ray absorption lines due to O VII and other ions observed by Chandra toward the bright blazar Mrk 421. We investigate the robustness of this detection by a reanalysis of the original…
Properties of structured coronal mass ejections in solar cycle 23
Bothmer, V.; Tripathi, D.; Cremades, H.
The Solar and Heliospheric Observatory has provided to date doubtlessly the best dataset of coronal observations ever taken over the course of a solar cycle. Structured coronal mass ejections, i.e. events with clear white-light fine structures, have been selected from the dataset of the large angle spectroscopic coronagraph during the period 1996 …
Observational evidence for a truncation of the star cluster initial mass function at the high mass end
Bastian, N.; Larsen, S. S.; Gieles, M. +3 more
We present the luminosity function (LF) of star clusters in M 51 based on HST/ACS observations taken as part of the Hubble Heritage project. The clusters are selected based on their size and with the resulting 5990 clusters we present one of the largest cluster samples of a single galaxy. We find that the LF can be approximated with a double power…
Propagation of whistler mode chorus to low altitudes: Spacecraft observations of structured ELF hiss
Gurnett, D. A.; Pickett, J. S.; Parrot, M. +3 more
We interpret observations of low-altitude electromagnetic ELF hiss observed on the dayside at subauroral latitudes. A divergent propagation pattern has been reported between 50° and 75° of geomagnetic latitude. The waves propagate with downward directed wave vectors which are slightly equatorward inclined at lower magnetic latitudes and slightly p…
Compact high-resolution spaceborne echelle grating spectrometer with acousto-optical tunable filter based order sorting for the infrared domain from 2.2 to 4.3 µm
Korablev, Oleg; Neefs, Eddy; Berkenbosch, Sophie +12 more
A new compact spaceborne high-resolution spectrometer developed for the European Space Agency's Venus Express spacecraft is described. It operates in the IR wavelength range of 2.2 to 4.3 µm and measures absorption spectra of minor constituents in the Venusian atmosphere. It uses a novel echelle grating with a groove density of 4 lines/mm in…
Interaction between eddies and mean flow in Jupiter's atmosphere: Analysis of Cassini imaging data
Ingersoll, Andrew P.; Del Genio, Anthony D.; Vasavada, Ashwin +2 more
Beebe et al. [Beebe, R.F., et al., 1980. Geophys. Res. Lett. 17, 1-4] and Ingersoll et al. [Ingersoll, A.P., et al., 1981. J. Geophys. Res. 86, 8733-8743] used images from Voyagers 1 and 2 to analyze the interaction between zonal winds and eddies in Jupiter's atmosphere. They reported a high positive correlation between Jupiter's eddy momentum flu…
Constraints on the initial mass function of the first stars
Ferrara, Andrea; Salvaterra, Ruben; Ciardi, Benedetta +1 more
Motivated by theoretical predictions that the first stars were predominantly very massive, we investigate the physics of the transition from an early epoch dominated by massive Pop III stars to a later epoch dominated by familiar low-mass Pop II/I stars by means of a numerically generated catalogue of dark matter haloes coupled with a self-consist…
Martian dayglow as seen by the SPICAM UV spectrograph on Mars Express
Bertaux, J. -L.; Leblanc, F.; Witasse, O. +2 more
In this paper we describe measurements of the Martian dayglow obtained by SPICAM UV spectrograph on board Mars Express between October 2004 and March 2005. Typical spectra (of more than 24,000 individual spectra) display the main features of the dayglow already reported more than 30 years ago (Barth et al., 1971, 1972). The variations with altitud…
Comment on the abundances of rotational and tangential discontinuities in the solar wind
Neugebauer, M.
Several recent studies indicate that there are very few discontinuities in the solar wind that have both the small changes in field magnitude and the large components of the magnetic field normal to the discontinuity surface that are commonly assumed to be signatures of rotational discontinuities (RDs). Those results call into question the validit…