Search Publications
Keck spectroscopic survey of strongly lensed galaxies in Abell 1703: further evidence of a relaxed, unimodal cluster
Jullo, E.; Richard, J.; Kneib, J. P. +2 more
Context: Strong gravitational lensing is a unique tool that can be used to accurately model the inner mass distribution of massive galaxy clusters. In particular, clusters with large Einstein radii provide a wealth of multiply imaged systems in the cluster core. Measuring the redshift of these multiple images provides strong constraints for precis…
Structural Parameters of Seven Small Magellanic Cloud Intermediate-Age and Old Star Clusters
Grebel, Eva K.; Gallagher, John S., III; Sabbi, Elena +9 more
We present structural parameters for the seven intermediate-age and old star clusters NGC 121, Lindsay 1, Kron 3, NGC 339, NGC 416, Lindsay 38, and NGC 419 in the Small Magellanic Cloud (SMC). We fit King profiles and Elson, Fall, and Freeman profiles to both surface-brightness and star-count data taken with the Advanced Camera for Surveys aboard …
Detecting nanoparticles at radio frequencies: Jovian dust stream impacts on Cassini/RPWS
Gurnett, D. A.; Kaiser, M. L.; Meyer-Vernet, N. +1 more
We analyse wave observations by the Cassini/RPWS instrument performed during the Jovian fly-by, when the on-board dust analyser recorded dust streams which were interpreted as nanoparticles moving at about the solar wind speed. The observed wave pulses are produced by ionisation of dust grains impacting the spacecraft. Nanoparticles are detected b…
X-Ray Substructure Studies of Four Galaxy Clusters Using XMM-Newton Data
Sarazin, Craig L.; Reiprich, Thomas H.; Finoguenov, Alexis +2 more
Mahdavi et al. find that the degree of agreement between weak lensing and X-ray mass measurements is a function of cluster radius. Numerical simulations also point out that X-ray mass proxies do not work equally well at all radii. The origin of the effect is thought to be associated with cluster mergers. Recent work presenting the cluster maps sho…
High-Resolution Timing Observations of Spin-Powered Pulsars with the AGILE Gamma-Ray Telescope
Halpern, J.; Costa, E.; Mereghetti, S. +67 more
Astro-rivelatore Gamma ad Immagini LEggero (AGILE) is a small gamma-ray astronomy satellite mission of the Italian Space Agency dedicated to high-energy astrophysics launched in 2007 April. Its ~ 1 µs absolute time tagging capability coupled with a good sensitivity in the 30 MeV-30 GeV range, with simultaneous X-ray monitoring in the 18-60 k…
Relativistic Broadening of Iron Emission Lines in a Sample of Active Galactic Nuclei
Brenneman, Laura W.; Reynolds, Christopher S.
We present a uniform X-ray spectral analysis of eight type-1 active galactic nuclei that have been previously observed with relativistically broadened iron emission lines. Utilizing data from the XMM-Newton European Photon Imaging Camera (EPIC-pn) we carefully model the spectral continuum, taking complex intrinsic absorption and emission into acco…
Spatially resolved mid-infrared observations of the triple system T Tauri
Wolf, S.; Ábrahám, P.; Henning, Th. +6 more
Aims: The aim of this study is to enhance our knowledge of the characteristics and distribution of the circumstellar dust associated with the individual components of the young hierarchical triple system T Tau.
Methods: To reach this goal, observations in the N-band (8-13 µm) with the two-telescope interferometric instrument MIDI at the …
A mechanism for electrostatic solitary structures in the Earth's magnetosheath
Lakhina, G. S.; Pickett, J. S.; ViñAs, A. F. +3 more
Electrostatic solitary waves (ESWs) have been observed in the Earth's magnetosheath region by Cluster. A mechanism for the generation of these structures in terms of electron-acoustic solitons and double layers is discussed. The model simulates the magnetosheath plasma by a four-component plasma system consisting of core electrons, two counterstre…
A binary engine fuelling HD 87643's complex circumstellar environment. Determined using AMBER/VLTI imaging
Waters, L. B. F. M.; Weigelt, G.; Hofmann, K. -H. +19 more
Context: The star HD 87643, exhibiting the “B[e] phenomenon”, has one of the most extreme infrared excesses for this object class. It harbours a large amount of both hot and cold dust, and is surrounded by an extended reflection nebula.
Aims: One of our major goals was to investigate the presence of a companion in HD87643. In addition, the pre…
EX Lupi in quiescence
Ábrahám, P.; Kóspál, Á.; Kun, M. +5 more
Aims: EX Lupi is the prototype of EXors, a subclass of low-mass pre-main sequence stars whose episodic eruptions are attributed to temporarily increased accretion. In quiescence the optical and near-infrared properties of EX Lup cannot be distinguished from those of normal T Tau stars. Here we investigate whether it is the circumstellar disk struc…