Search Publications
Missions
Journals
Publication Years
A magnetic cycle of τ Bootis? The coronal and chromospheric view
Schmitt, J. H. M. M.; Günther, H. M.; Poppenhaeger, K.
τ Bootis is a late F-type main sequence star orbited by a Hot Jupiter. During the last years spectropolarimetric observations led to the hypothesis that this star may host a global magnetic field that switches its polarity once per year, indicating a very short activity cycle of only one year duration. In our ongoing observational campaign, we hav…
Herschel/HIFI observations of red supergiants and yellow hypergiants. I. Molecular inventory
Waters, L. B. F. M.; Menten, K. M.; Olofsson, H. +17 more
Context. Red supergiant stars (RSGs) and yellow hypergiant stars (YHGs) are believed to be the high-mass counterparts of stars in the asymptotic giant branch (AGB) and early post-AGB phases. As such, they are scarcer and the properties and evolution of their envelopes are still poorly understood.
Aims: We study the mass-loss in the post main-…
A multiwavelength survey of AGN in massive clusters: AGN detection and cluster AGN fraction
Sarajedini, Vicki L.; Klesman, Alison J.
We aim to study the effect of environment on the presence and fuelling of active galactic nuclei (AGNs) in massive galaxy clusters. We explore the use of different AGN detection techniques with the goal of selecting AGN across a broad range of luminosities, AGN/host galaxy flux ratios and obscuration levels. From a sample of 12 galaxy clusters at …
A Unified and Very Fast Way for Computing the Global Potential and Linear Force-Free Fields
Feng, Xueshang; Jiang, Chaowei
We present a fast solver for computing potential and linear force-free fields (LFFF) above the full solar disk with a synoptic magnetic map as input. The global potential field and the LFFF are dealt with in a unified way by solving a three-dimensional Helmholtz equation in a spherical shell and a two-dimensional Poisson equation on the solar surf…
Polar cap arcs from the magnetosphere to the ionosphere: kinetic modelling and observations by Cluster and TIMED
Lointier, G.; Simon Wedlund, C.; Trotignon, J. -G. +4 more
On 1 April 2004 the GUVI imager onboard the TIMED spacecraft spots an isolated and elongated polar cap arc. About 20 min later, the Cluster satellites detect an isolated upflowing ion beam above the polar cap. Cluster observations show that the ions are accelerated upward by a quasi-stationary electric field. The field-aligned potential drop is es…
Search for Radiative Decays of Cosmic Background Neutrino using Cosmic Infrared Background Energy Spectrum
Matsuura, Shuji; Kim, Shin-Hong; Takemasa, Ken-ichi +1 more
We propose to search for the neutrino radiative decay by fitting a photon energy spectrum of the cosmic infrared background to a sum of the photon energy spectrum from the neutrino radiative decay and a continuum. By comparing the present cosmic infrared background energy spectrum observed by AKARI and Spitzer to the photon energy spectrum expecte…
Solar Intranetwork Magnetic Elements: Bipolar Flux Appearance
Wang, Jingxiu; Li, Hui; Jin, Chunlan +1 more
This study aims to quantify characteristic features of the bipolar flux appearance of solar intranetwork (IN) magnetic elements. To attack this problem, we use the Narrowband Filter Imager (NFI) magnetograms from the Solar Optical Telescope (SOT) on board Hinode; these data are from quiet and enhanced network areas. Cluster emergence of mixed pola…
Thermospheric/mesospheric temperatures on Venus: Results from ground-based high-resolution spectroscopy of CO 2 in 1990/1991 and comparison to results from 2009 and between other techniques
Mahieux, Arnaud; Sonnabend, Guido; Sornig, Manuela +8 more
We report temperatures in Venus' upper mesosphere/lower thermosphere, deduced from reanalyzing very high resolution infrared spectroscopy of CO 2 emission lines acquired in 1990 and 1991. Kinetic temperatures at ∼110 km altitude (0.15 Pa) are derived from the Doppler width of fully-resolved single line profiles measured near 10.4 µ…
X-Ray Groups of Galaxies at 0.5 < z < 1 in zCOSMOS: Increased AGN Activities in High Redshift Groups
Koekemoer, Anton M.; Tresse, Laurence; Contini, Thierry +48 more
We present a photometric and spectroscopic study of galaxies at 0.5 < z < 1 as a function of the environment based on data from the zCOSMOS survey. There is a fair amount of evidence that galaxy properties depend on the mass of groups and clusters, in the sense that quiescent galaxies prefer more massive systems. We base our analysis on a ma…
Short Gas Dissipation Timescales: Diskless Stars in Taurus and Chamaeleon I
Briceño, Cesar; Calvet, Nuria; Herczeg, Gregory +1 more
We present an Advanced Camera for Surveys/Solar Blind Channel far-ultraviolet (FUV) study of H2 gas in 12 weak T Tauri stars in nearby star-forming regions. The sample consists of sources which have no evidence of inner disk dust. Our new FUV spectra show that in addition to the dust, the gas is depleted from the inner disk. This sample…