Search Publications
On-Orbit Degradation of Solar Instruments
Schmutz, W.; Berghmans, D.; Auchère, F. +38 more
We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that took place at the Solar Terrestrial Centre of Excellence (Royal Observatory of Belgium) in Brussels on 3 May 2012. The aim of this workshop was …
Signatures of kinetic instabilities in the solar wind
Landi, Simone; Hellinger, Petr; Velli, Marco +3 more
An analysis of ion non-thermal properties in the fast solar wind based on Ulysses data is reported. The radial evolution of the main proton moments (density, temperature, and drift velocities) and their empirical correlations with other plasma parameters are investigated in detail and compared with theoretical expectations. The stability of the pl…
Structural Evolution of Early-type Galaxies to z = 2.5 in CANDELS
Bell, Eric F.; Ferguson, Henry C.; Grogin, Norman A. +18 more
Projected axis ratio measurements of 880 early-type galaxies at redshifts 1 < z < 2.5 selected from CANDELS are used to reconstruct and model their intrinsic shapes. The sample is selected on the basis of multiple rest-frame colors to reflect low star-formation activity. We demonstrate that these galaxies as an ensemble are dust-poor and tra…
Dynamics of Saturn’s great storm of 2010-2011 from Cassini ISS and RPWS
West, Robert A.; Porco, Carolyn C.; Dyudina, Ulyana A. +6 more
Saturn’s quasi-periodic planet-encircling storms are the largest convecting cumulus outbursts in the Solar System. The last eruption was in 1990 (Sánchez-Lavega, A. [1994]. Chaos 4, 341-353). A new eruption started in December 2010 and presented the first-ever opportunity to observe such episodic storms from a spacecraft in orbit around Saturn (Fi…
A comprehensive picture of baryons in groups and clusters of galaxies
Zhang, Y. -Y.; Martinet, N.; Durret, F. +3 more
Aims: Based on XMM-Newton, Chandra, and SDSS data, we investigate the baryon distribution in groups and clusters and its use as a cosmological constraint. For this, we considered a sample of 123 systems with temperatures kT500 = 1.0-9.0 keV, total masses in the mass range M500 = (~1013-4 × 1015)h
Statistical analysis of EMIC waves in plasmaspheric plumes from Cluster observations
Bortnik, J.; Mann, I. R.; Darrouzet, F. +1 more
electromagnetic ion cyclotron (EMIC) wave generation in plasmaspheric plumes has been the subject of extensive discussion. Theory predicts that regions of detached cold, dense plasma immersed in relatively low background magnetic field should aid EMIC wave growth and may provide conditions for interaction between the EMIC waves and relativistic (M…
Chemical Evolution in High-mass Star-forming Regions: Results from the MALT90 Survey
Hoq, Sadia; Jackson, James M.; Foster, Jonathan B. +7 more
The chemical changes of high-mass star-forming regions provide a potential method for classifying their evolutionary stages and, ultimately, ages. In this study, we search for correlations between molecular abundances and the evolutionary stages of dense molecular clumps associated with high-mass star formation. We use the molecular line maps from…
Constraints on decreases in η Carinae's mass-loss from 3D hydrodynamic simulations of its binary colliding winds
Gull, T. R.; Corcoran, M. F.; Madura, T. I. +6 more
Recent work suggests that the mass-loss rate of the primary star ηA in the massive colliding wind binary η Carinae dropped by a factor of 2-3 between 1999 and 2010. We present results from large- (±1545 au) and small- (±155 au) domain, 3D smoothed particle hydrodynamics (SPH) simulations of η Car's colliding winds for three ηA
Hot Gas Lines in T Tauri Stars
Edwards, Suzan; Herczeg, Gregory J.; Valenti, Jeff A. +20 more
For Classical T Tauri Stars (CTTSs), the resonance doublets of N V, Si IV, and C IV, as well as the He II 1640 Å line, trace hot gas flows and act as diagnostics of the accretion process. In this paper we assemble a large high-resolution, high-sensitivity data set of these lines in CTTSs and Weak T Tauri Stars (WTTSs). The sample comprises 35 star…
UVUDF: Ultraviolet Imaging of the Hubble Ultra Deep Field with Wide-Field Camera 3
Finkelstein, Steven L.; Ferguson, Henry C.; Giavalisco, Mauro +23 more
We present an overview of a 90 orbit Hubble Space Telescope treasury program to obtain near-ultraviolet imaging of the Hubble Ultra Deep Field using the Wide Field Camera 3 UVIS detector with the F225W, F275W, and F336W filters. This survey is designed to: (1) investigate the episode of peak star formation activity in galaxies at 1 < z < 2.5…