Search Publications
Discriminating contamination from particle components in spectra of Cassini's dust detector CDA
Kempf, S.; Postberg, F.; Srama, R. +5 more
The Chemical Analyser subsystem of the Cosmic Dust Analyser (CDA) aboard the Cassini spacecraft performs in situ measurements of the chemical composition of dust in space. The instrument records time-of-flight mass spectra of cations, extracted from the impact cloud that is created by high-velocity particle impacts onto the detector target. Thus, …
Organic matter in space: from star dust to the Solar System
Kwok, Sun
Organic compounds of high degree of complexity are now known to be widespread in the Universe, ranging from objects in our Solar System to distant galaxies. Through the techniques of millimeter-wave spectroscopy, over 140 molecules have been identified through their rotational transitions. Space infrared spectroscopy has detected the stretching an…
Separatrix regions of magnetic reconnection at the magnetopause
Lavraud, B.; André, M.; Vaivads, A. +5 more
Using data from the four Cluster spacecraft we study the separatrix regions of magnetic reconnection sites at the dayside magnetopause under conditions when reconnection is occurring in the magnetopause current layer which separates magnetosheath plasma from the hot magnetospheric plasma sheet. We define the separatrix region as the region between…
A New Sample of Buried Active Galactic Nuclei Selected from the Second XMM-Newton Serendipitous Source Catalogue
Awaki, Hisamitsu; Terashima, Yuichi; Noguchi, Kazuhisa
We present the results of X-ray spectral analysis of 22 active galactic nuclei (AGNs) with a small scattering fraction selected from the Second XMM-Newton Serendipitous Source Catalogue using hardness ratios. They are candidates of buried AGNs, since a scattering fraction, which is a fraction of scattered emission by the circumnuclear photoionized…
The Apparent Layered Structure of the Heliospheric Current Sheet: Multi-Spacecraft Observations
Sauvaud, J. -A.; Luhmann, J. G.; Lavraud, B. +9 more
Multiple current sheet crossings are ubiquitous features of the solar wind associated with high-beta plasma sheets, notably during the passage of the heliospheric current sheet (HCS). As the HCS is being convected past near-Earth, we attempt to resolve spatial scales and temporal variations of the apparent layered structure of the HCS, including a…
Multiwavelength observations of a rich galaxy cluster at z ∼ 1. The HST/ACS colour-magnitude diagram
Böhringer, H.; Lidman, C.; Perlmutter, S. +12 more
Context: XMMU J1229+0151 is a rich galaxy cluster with redshift z=0.975 that was serendipitously detected in X-rays within the scope of the XMM-Newton Distant Cluster Project. Both HST/ACS observations in the i775 and z850 passbands and VLT/FORS2 spectroscopy were obtained, in addition to follow-up Near-Infrared (NIR) imaging…
A Strong Excess in the 20-100 keV Emission of NGC 1365
Maiolino, R.; Bianchi, S.; Elvis, M. +8 more
We present a new Suzaku observation of the obscured active galactic nucleus in NGC 1365, revealing an unexpected excess of X-rays above 20 keV of at least a factor ~2 with respect to the extrapolation of the best-fitting 3-10 keV model. Additional Swift-BAT and Integral-IBIS observations show that the 20-100 keV is concentrated within ~1.5 arcmin …
12 New Galactic Wolf-Rayet Stars Identified via 2MASS + Spitzer/GLIMPSE
Van Dyk, Schuyler D.; Mauerhan, Jon C.; Morris, Pat W.
We report new results from our effort to identify obscured Wolf-Rayet stars in the Galaxy. Candidates were selected by their near-infrared (Two Micron All Sky Survey; 2MASS) and mid-infrared (Spitzer/GLIMPSE) color excesses, which are consistent with free-free emission from ionized stellar winds and thermal excess from hot dust. We have confirmed …
Analysis and interpretation of Cassini Titan radar altimeter echoes
Hensley, Scott; Gim, Yonggyu; Cassini Radar Team +3 more
The Cassini spacecraft has acquired 25 radar altimeter elevation profiles along Titan's surface as of April 2008, and we have analyzed 18 of these for which there are currently reconstructed ephemeris data. Altimeter measurements were collected at spatial footprint sizes from 6-60 km along ground tracks of length 400-3600 km. The elevation profile…
Molecular gas in NUclei of GAlaxies (NUGA). XII. The head-on collision in NGC 1961
Tacconi, L. J.; Hunt, L. K.; Schinnerer, E. +6 more
We present high-resolution maps of the CO(1-0) and CO(2-1) emission from the LINER 2 galaxy NGC 1961. This galaxy is unusual among late-type (Sc) disk galaxies in having a very large radial extent and inferred dynamical mass. We propose a head-on collision scenario to explain the perturbed morphology of this galaxy - both the off-centered rings an…