Search Publications
Tidal heating in Enceladus
Meyer, Jennifer; Wisdom, Jack
The heating in Enceladus in an equilibrium resonant configuration with other saturnian satellites can be estimated independently of the physical properties of Enceladus. We find that equilibrium tidal heating cannot account for the heat that is observed to be coming from Enceladus. Equilibrium heating in possible past resonances likewise cannot ex…
Evidence for an Elongated (>60 Ion Skin Depths) Electron Diffusion Region during Fast Magnetic Reconnection
Eastwood, J. P.; Phan, T. D.; Mozer, F. S. +2 more
Observations of an extremely elongated electron diffusion region occurring during fast reconnection are presented. Cluster spacecraft in situ observations of an expanding reconnection exhaust reveal a broad current layer (∼10 ion skin depths thick) supporting the reversal of the reconnecting magnetic field together with an intense current embedded…
An alternative hypothesis for the outburst mechanism in supergiant fast X-ray transients: the case of IGR J11215-5952
Götz, D.; Mereghetti, S.; Sidoli, L. +4 more
Context: The physical mechanism responsible for the short outbursts in a recently recognised class of high mass X-ray binaries, the supergiant fast X-ray transients (SFXTs), is still unknown. Two main hypotheses have been proposed to date: the sudden accretion by the compact object of small ejections originating in a clumpy wind from the supergian…
The Morphological Content of 10 EDisCS Clusters at 0.5 < z < 0.8
Pelló, R.; Poggianti, B.; Milvang-Jensen, B. +12 more
We describe Hubble Space Telescope (HST) imaging of 10 of the 20 ESO Distant Cluster Survey (EDisCS) fields. Each ~40 arcmin2 field was imaged in the F814W filter with the Advanced Camera for Surveys Wide Field Camera. Based on these data, we present visual morphological classifications for the ~920 sources per field that are brighter t…
Shapes of the saturnian icy satellites and their significance
Burns, J. A.; Denk, T.; Porco, C. +10 more
The sizes and shapes of six icy saturnian satellites have been measured from Cassini Imaging Science Subsystem (ISS) data, employing limb coordinates and stereogrammetric control points. Mimas, Enceladus, Tethys, Dione and Rhea are well described by triaxial ellipsoids; Iapetus is best represented by an oblate spheroid. All satellites appear to ha…
Tracing the evolution in the iron content of the intra-cluster medium
Tozzi, P.; Balestra, I.; Mainieri, V. +5 more
Context: We present a Chandra analysis of the X-ray spectra of 56 clusters of galaxies at z ⪆ 0.3, which cover a temperature range of 3 ⪉ kT ⪉ 15 keV.
Aims: Our analysis is aimed at measuring the iron abundance in the intra-cluster medium (ICM) out to the highest redshift probed to date.
Methods: We made use of combined spectral analysis p…
An improved measurement of the flux distribution of the Lyα forest in QSO absorption spectra: the effect of continuum fitting, metal contamination and noise properties
Viel, M.; Carswell, R. F.; Kim, T. -S. +2 more
We have performed an extensive Voigt profile analysis of the neutral hydrogen (HI) and metal absorption present in a sample of 18 high-resolution, high signal-to-noise ratio quasi-stellar object (QSO) spectra observed with the Very Large Telescope Ultraviolet and Visual Echelle Spectrograph. We use this analysis to separate the metal contribution …
Association of the jets of Enceladus with the warmest regions on its south-polar fractures
Porco, Carolyn C.; Spitale, Joseph N.
Jets of material have been seen emanating from the south-polar terrain of Saturn's satellite Enceladus. Observations have shown that this region is anomalously warm, with the hottest measured temperatures coinciding with the four `tiger stripe' fractures, named Alexandria, Cairo, Baghdad and Damascus, that straddle the region. Here we use Cassini …
RPC-MAG The Fluxgate Magnetometer in the ROSETTA Plasma Consortium
Motschmann, Uwe; Richter, Ingo; Carr, Chris +11 more
The fluxgate magnetometer experiment onboard the ROSETTA spacecraft aims to measure the magnetic field in the interaction region of the solar wind plasma with comet 67P/Churyumov-Gerasimenko. It consists of a system of two ultra light (about 28 g each ) triaxial fluxgate magnetometer sensors, mounted on the 1.5 m long spacecraft boom. The measurem…
I Zw 18 Revisited with HST ACS and Cepheids: New Distance and Age
Saha, A.; Tosi, M.; Clementini, G. +9 more
We present new V- and I-band HST ACS photometry of I Zw 18, the most metal-poor blue compact dwarf (BCD) galaxy in the nearby universe. It has been argued in the past that I Zw 18 is a very young system that started forming stars only <~500 Myr ago, but other work has hinted that older (>~1 Gyr) red giant branch (RGB) stars may also exist. O…