Search Publications
Evolution of red-sequence cluster galaxies from redshift 0.8 to 0.4: ages, metallicities, and morphologies
Moustakas, J.; Pelló, R.; White, S. D. M. +14 more
We present a comprehensive analysis of the stellar population properties and morphologies of red-sequence galaxies in 24 clusters and groups from z∼0.75 to z∼0.45. The dataset, consisting of 215 spectra drawn from the ESO Distant Cluster Survey, constitutes the largest spectroscopic sample at these redshifts for which such an analysis has been con…
PAMELA, DAMA, INTEGRAL and signatures of metastable excited WIMPs
Finkbeiner, Douglas P.; Slatyer, Tracy R.; Weiner, Neal +1 more
Models of dark matter with ~ GeV scale force mediators provide attractive explanations of many high energy anomalies, including PAMELA, ATIC, and the WMAP haze. At the same time, by exploiting the ~ MeV scale excited states that are automatically present in such theories, these models naturally explain the DAMA/LIBRA and INTEGRAL signals through t…
Density and Kinematic Cusps in M54 at the Heart of the Sagittarius Dwarf Galaxy: Evidence for A 104 M sun Black Hole?
Dalessandro, E.; Bellazzini, M.; Mackey, A. D. +8 more
We report the detection of a stellar density cusp and a velocity dispersion increase in the center of the globular cluster M54, located at the center of the Sagittarius dwarf galaxy (Sgr). The central line-of-sight velocity dispersion is 20.2 ± 0.7 km s-1, decreasing to 16.4 ± 0.4 km s-1 at 2farcs5 (0.3 pc). Modeling the kine…
The CoRoT target HD 175726: an active star with weak solar-like oscillations
Auvergne, M.; Baudin, F.; García, R. A. +17 more
Context: The CoRoT short runs give us the opportunity to observe a large variety of late-type stars through their solar-like oscillations. We report observations of the star HD 175726 that lasted for 27 days during the first short run of the mission. The time series reveals a high-activity signal and the power spectrum presents an excess due to so…
A Note on the Torsional Oscillation at Solar Minimum
Thompson, M. J.; Howe, R.; Komm, R. +3 more
We examine the evolution of the zonal flow pattern in the upper solar convection zone during the current extended solar minimum, and compare it with that during the previous minimum. The results suggest that a configuration matching that at the previous minimum was reached during 2008, but that the flow band corresponding to the new cycle has been…
Discrete classification and electron energy spectra of Titan's varied magnetospheric environment
Coates, A. J.; Smith, H. T.; Young, D. T. +2 more
We analyse combined electron spectra across the dynamic range of both Cassini electron sensors in order to characterise the background plasma environment near Titan for 54 Cassini-Titan encounters as of May 2009. We characterise the encounters into four broad types: Plasma sheet, Lobe-like, Magnetosheath and Bimodal. Despite many encounters occurr…
Model-data comparisons for Titan's nightside ionosphere
Coates, A. J.; Wahlund, J. -E.; Neubauer, F. M. +9 more
Solar and X-ray radiation and energetic plasma from Saturn's magnetosphere interact with the upper atmosphere producing an ionosphere at Titan. The highly coupled ionosphere and upper atmosphere system mediates the interaction between Titan and the external environment. A model of Titan's nightside ionosphere will be described and the results comp…
A search for diffuse radio emission in the relaxed, cool-core galaxy clusters A1068, A1413, A1650, A1835, A2029, and Ophiuchus
Markevitch, M.; Govoni, F.; Carretti, E. +4 more
Aims: We analyze sensitive, high-dynamic-range, observations to search for extended, diffuse, radio emission in relaxed and cool-core galaxy clusters.
Methods: We performed deep 1.4 GHz Very Large Array observations, of A1068, A1413, A1650, A1835, A2029, and complemented our dataset with archival observations of Ophiuchus.
Results: We find…
On the continuum intensity distribution of the solar photosphere
Rouppe van der Voort, L.; Wedemeyer-Böhm, S.
Context: For many years, there seemed to be significant differences between the continuum intensity distributions derived from observations and simulations of the solar photosphere.
Aims: In order to settle the discussion on these apparent discrepancies, we present a detailed comparison between simulations and seeing-free observations that tak…
Generation of highly energetic electrons at reconnection outflow shocks during solar flares
Mann, G.; Aurass, H.; Warmuth, A.
Context: During solar flares a large amount of energy is suddenly released and partly transferred into energetic electrons. They are of special interest since a substantial part of the energy released during a flare is deposited into the energetic electrons. RHESSI observations, e.g. of the 2003 October 28 solar event, show that 1036 el…