Search Publications
The chromospherically active binary star EI Eridani: I. Absolute dimensions
Strassmeier, K. G.; Weber, M.; Granzer, T. +2 more
We present a detailed determination of the astrophysical parameters of the chromospherically active binary star EI Eridani. Our new radial velocities allow to improve the set of orbital elements and reveal long-term variations of the barycentric velocity. A possible third-body orbit with a period of {≈ 19} years is presented. Absolute parameters a…
A new spectroscopic and interferometric study of the young stellar object V645 Cygni
Weigelt, G.; Hofmann, K. -H.; Schertl, D. +14 more
Aims: We present the results of high-resolution optical spectroscopy, low-resolution near-IR spectroscopy and near-infrared speckle interferometry of the massive young stellar object candidate V645 Cyg, acquired to refine its fundamental parameters and the properties of its circumstellar envelope.
Methods: Speckle interferometry in the H- and …
The dark matter interpretation of the 511 keV line
Bœhm, Céline
The 511 keV high-precision map obtained by the INTEGRAL/SPI experiment suggested a surprisingly large amount of positrons in our galaxy with respect to 'naive' astrophysical expectations. Although an astrophysical origin is not excluded, this signal may shed light on dark matter. Here we discuss a possible MeV dark matter interpretation of the 511…
Spectroscopic binaries among Hipparcos M giants. II. Binary frequency
Jorissen, A.; Udry, S.; Famaey, B. +3 more
Context: This paper is the second in a series devoted to studying the properties of binaries with M giant primaries.
Aims: The binary frequency of field M giants is derived and compared with the binary fraction of K giants.
Methods: Diagrams of the CORAVEL spectroscopic parameter Sb (measuring the average line width) vs. radial-velocity st…
Near-infrared polarimetry of the Red Rectangle
Witt, A. N.; Gledhill, T. M.; Davis, C. J. +1 more
Imaging polarimetry through J and H broad-band filters and a 3.4 µm narrow-band filter is used to highlight the regions of scattered light in the Red Rectangle. We find that the scattered light identifies the circumbinary dust component of the molecular disc seen in CO emission. This region also appears to be the origin of the recently disco…
Suzaku Observation of the Metallicity in the Interstellar Medium of NGC 4258
Isobe, Naoki; Gandhi, Poshak; Sato, Kosuke +7 more
The Suzaku X-ray satellite observed the nearby spiral galaxy NGC 4258 for a total good exposure time of 100 ks. We present an analysis of the Suzaku XIS data, in which we confirm that the 0.5-2 keV spectra of the interstellar medium (ISM) are well-represented by a two-temperature model. The cool and hot ISM temperatures are 0.23±0.01 and 0.58±0.01…
Retrieval of Mars surface physical properties from OMEGA hyperspectral images using regularized sliced inverse regression
Douté, S.; Bernard-Michel, C.; Fauvel, M. +2 more
In this paper, a method based on modeling and statistics is proposed to evaluate the physical properties of surface icy materials on Mars from hyperspectral images collected by the OMEGA instrument aboard the Mars Express spacecraft. The approach is based on the estimation of the functional relationship F between observed spectra and relevant phys…
Multipoint, high time resolution galactic cosmic ray observations associated with two interplanetary coronal mass ejections
Mulligan, T.; Galametz, M.; Spence, H. E. +3 more
Galactic cosmic rays (GCRs) play an important role in our understanding of the interplanetary medium (IPM). The causes of their short timescale variations, however, remain largely unexplored. In this paper, we compare high time resolution, multipoint space-based GCR data to explore structures in the IPM that cause these variations. To ensure that …
Relationship between the topological skeleton, current concentrations, and 3D magnetic reconnection sites in the solar atmosphere
Priest, E. R.; Maclean, R. C.; Büchner, J.
Aims: The aim of this work is to determine the relationship between the 3D structure of the coronal magnetic field, diagnosed by the topological skeleton, and current concentrations as potential sites of 3D reconnection.
Methods: We utilised the results of 3D numerical MHD simulations of an observed EUV bright point (BP) in the solar atmospher…
The Interstellar Heliopause Probe: Heliospheric Boundary Explorer Mission to the Interstellar Medium
Wimmer-Schweingruber, Robert F.; McNutt, Ralph; IHP/HEX Team
The Sun, driving a supersonic solar wind, cuts out of the local interstellar medium a giant plasma bubble, the heliosphere. ESA, jointly with NASA, has had an important role in the development of our current understanding of the Suns' immediate neighborhood. Ulysses is the only spacecraft exploring the third, out-of-ecliptic dimension, while SOHO …