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Revealing the Properties of Dark Matter in the Merging Cluster MACS J0025.4-1222
Treu, Tommaso; Bradač, Maruša; Allen, Steven W. +5 more
We constrain the physical nature of dark matter using the newly identified massive merging galaxy cluster MACS J0025.4-1222. As was previously shown by the example of the Bullet Cluster (1E 0657-56), such systems are ideal laboratories for detecting isolated dark matter and distinguishing between cold dark matter (CDM) and other scenarios (e.g., s…
Nonlinear Force-free Field Modeling of a Solar Active Region around the Time of a Major Flare and Coronal Mass Ejection
Aulanier, G.; Schrijver, C. J.; Amari, T. +14 more
Solar flares and coronal mass ejections are associated with rapid changes in field connectivity and are powered by the partial dissipation of electrical currents in the solar atmosphere. A critical unanswered question is whether the currents involved are induced by the motion of preexisting atmospheric magnetic flux subject to surface plasma flows…
Coupling photochemistry with haze formation in Titan's atmosphere, Part II: Results and validation with Cassini/Huygens data
Coustenis, A.; Lavvas, P. P.; Vardavas, I. M.
The new one-dimensional radiative-convective/photochemical/microphysical model described in Part I is applied to the study of Titan's atmospheric processes that lead to haze formation. Our model generates the haze structure from the gaseous species photochemistry. Model results are presented for the species vertical concentration profiles, haze fo…
Flare Observations
Benz, Arnold O.
Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays at 100 MeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, and SOHO have enlarged widely the observational base. They have revealed a number of surprises: Corona…
The first XMM-Newton slew survey catalogue: XMMSL1
Altieri, B.; Read, A. M.; Esquej, P. +3 more
Aims:We report on the production of a large area, shallow, sky survey, from XMM-Newton slews. The great collecting area of the mirrors coupled with the high quantum efficiency of the EPIC detectors have made XMM-Newton the most sensitive X-ray observatory flown to date. We use data taken with the EPIC-pn camera during slewing manoeuvres to perform…
Image Stabilization System for Hinode (Solar-B) Solar Optical Telescope
Ichimoto, K.; Kobayashi, K.; Tsuneta, S. +16 more
The Hinode Solar Optical Telescope (SOT) is the first space-borne visible-light telescope that enables us to observe magnetic-field dynamics in the solar lower atmosphere with 0.2 - 0.3 arcsec spatial resolution under extremely stable (seeing-free) conditions. To achieve precise measurements of the polarization with diffraction-limited images, sta…
An Infrared Survey of Brightest Cluster Galaxies. II. Why are Some Brightest Cluster Galaxies Forming Stars?
Baum, Stefi A.; O'Dea, Christopher P.; Sarazin, Craig L. +12 more
Quillen et al. presented an imaging survey with the Spitzer Space Telescope of 62 brightest cluster galaxies with optical line emission located in the cores of X-ray-luminous clusters. They found that at least half of these sources have signs of excess IR emission. Here we discuss the nature of the IR emission and its implications for cool core cl…
Unveiling Obscured Accretion in the Chandra Deep Field-South
Pozzi, F.; Fiore, F.; Vignali, C. +10 more
We make use of deep HST, VLT, Spitzer, and Chandra data on the Chandra Deep Field-South to constrain the number of Compton-thick AGNs in this field. We show that sources with high 24 µm-to-optical flux ratios and red colors form a distinct source population, and that their infrared luminosity is dominated by AGN emission. Analysis of the X-r…
Hinode SOT Observations of Solar Quiescent Prominence Dynamics
Tsuneta, Saku; Shimizu, Toshifumi; Okamoto, Takenori J. +9 more
We report findings from multihour 0.2'' resolution movies of solar quiescent prominences (QPs) observed with the Solar Optical Telescope (SOT) on the Hinode satellite. The observations verify previous findings of filamentary downflows and vortices in QPs. SOT observations also verify large-scale transverse oscillations in QPs, with periods of 20-4…
Recent Structural Evolution of Early-Type Galaxies: Size Growth from z = 1 to z = 0
Franx, Marijn; Illingworth, Garth D.; van der Wel, Arjen +4 more
Strong size and internal density evolution of early-type galaxies between z ~ 2 and the present has been reported by several authors. Here we analyze samples of nearby and distant (z ~ 1) galaxies with dynamically measured masses in order to confirm the previous, model-dependent results and constrain the uncertainties that may play a role. Velocit…