Search Publications
Shear heating as the origin of the plumes and heat flux on Enceladus
Spencer, J. R.; Nimmo, F.; Pappalardo, R. T. +1 more
Enceladus, a small icy satellite of Saturn, has active plumes jetting from localized fractures (`tiger stripes') within an area of high heat flux near the south pole. The plume characteristics and local high heat flux have been ascribed either to the presence of liquid water within a few tens of metres of the surface, or the decomposition of clath…
Observation of Inertial Energy Cascade in Interplanetary Space Plasma
Bavassano, B.; Pietropaolo, E.; Bruno, R. +6 more
Direct evidence for the presence of an inertial energy cascade, the most characteristic signature of hydromagnetic turbulence (MHD), is observed in the solar wind by the Ulysses spacecraft. After a brief rederivation of the equivalent of Yaglom’s law for MHD turbulence, a linear relation is indeed observed for the scaling of mixed third-order stru…
Reconstruction of solar total irradiance since 1700 from the surface magnetic flux
Solanki, S. K.; Krivova, N. A.; Balmaceda, L.
Context: Total solar irradiance changes by about 0.1% between solar activity maximum and minimum. Accurate measurements of this quantity are only available since 1978 and do not provide information on longer-term secular trends.
Aims: In order to reliably evaluate the Sun's role in recent global climate change, longer time series are, however,…
Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs
Zuckerman, B.; Song, Inseok; McElwain, Michael +1 more
Dusty debris disks around main-sequence stars are signposts for the existence of planetesimals and exoplanets. From cross-correlating Hipparcos stars with the IRAS catalogs, we identify 146 stars within 120 pc of Earth that show excess emission at 60 µm. This search took special precautions to avoid false positives. Our sample is reasonably …
C IV λ1549 as an Eigenvector 1 Parameter for Active Galactic Nuclei
Sulentic, Jack W.; Marziani, Paola; Negrete, C. Alenka +2 more
We are exploring a spectroscopic unification for all types of broad-line emitting AGNs. The four-dimensional Eigenvector 1 (4DE1) parameter space organizes quasar diversity in a sequence primarily governed by Eddington ratio. This paper considers the role of C IV λ1549 measures as 4DE1 diagnostics. We use HST archival spectra for 130 sources with …
Coronal ``Wave'': Magnetic Footprint of a Coronal Mass Ejection?
Harra, Louise K.; Attrill, Gemma D. R.; van Driel-Gesztelyi, Lidia +1 more
We investigate the properties of two ``classical'' EUV Imaging Telescope (EIT) coronal waves. The two source regions of the associated coronal mass ejections (CMEs) possess opposite helicities, and the coronal waves display rotations in opposite senses. We observe deep core dimmings near the flare site and also widespread diffuse dimming, accompan…
The representative XMM-Newton cluster structure survey (REXCESS) of an X-ray luminosity selected galaxy cluster sample
Zhang, Y. -Y.; Finoguenov, A.; Böhringer, H. +31 more
Context: The largest uncertainty for cosmological studies using clusters of galaxies is introduced by our limited knowledge of the statistics of galaxy cluster structure, and of the scaling relations between observables and cluster mass.
Aims: To improve on this situation we have started an XMM-Newton Large Programme for the in-depth study of …
The Centers of Early-Type Galaxies with Hubble Space Telescope. VI. Bimodal Central Surface Brightness Profiles
Filippenko, Alexei V.; Ho, Luis C.; Gebhardt, Karl +9 more
We combine several HST investigations on the central structure of early-type galaxies to generate a large sample of surface photometry. The studies selected were those that used the ``Nuker law'' to characterize the inner light distributions of the galaxies. The sample comprises WFPC1 and WFPC2 V-band observations published earlier by our group, R…
Temperature profiles of a representative sample of nearby X-ray galaxy clusters
Finoguenov, A.; Böhringer, H.; Arnaud, M. +4 more
Context: A study of the structural and scaling properties of the temperature distribution of the hot, X-ray emitting intra-cluster medium of galaxy clusters, and its dependence on dynamical state, can give insights into the physical processes governing the formation and evolution of structure.
Aims: Accurate temperature measurements are a pre-…
A Log-Quadratic Relation for Predicting Supermassive Black Hole Masses from the Host Bulge Sérsic Index
Graham, Alister W.; Driver, Simon P.
We reinvestigate the correlation between black hole mass and bulge concentration. With an increased galaxy sample (totaling 27) and updated estimates of galaxy distances, black hole masses, and Sérsic indices n-a measure of concentration-we perform a least-squares regression analysis to obtain a relation suitable for the purpose of predicting blac…