Search Publications
Influence of the Ambient Solar Wind Flow on the Propagation Behavior of Interplanetary Coronal Mass Ejections
Veronig, Astrid M.; Temmer, Manuela; Vršnak, Bojan +3 more
We study three coronal mass ejection (CME)/interplanetary coronal mass ejection (ICME) events (2008 June 1-6, 2009 February 13-18, and 2010 April 3-5) tracked from Sun to 1 AU in remote-sensing observations of Solar Terrestrial Relations Observatory Heliospheric Imagers and in situ plasma and magnetic field measurements. We focus on the ICME propa…
Scaling Relations and Overabundance of Massive Clusters at z >~ 1 from Weak-lensing Studies with the Hubble Space Telescope
Gladders, M. D.; Ford, H. C.; Huang, X. +22 more
We present weak gravitational lensing analysis of 22 high-redshift (z >~ 1) clusters based on Hubble Space Telescope images. Most clusters in our sample provide significant lensing signals and are well detected in their reconstructed two-dimensional mass maps. Combining the current results and our previous weak-lensing studies of five other hig…
Rocky Extrasolar Planetary Compositions Derived from Externally Polluted White Dwarfs
Koester, D.; Zuckerman, B.; Klein, B. +1 more
We report Keck High Resolution Echelle Spectrometer data and model atmosphere analysis of two helium-dominated white dwarfs, PG1225-079 and HS2253+8023, whose heavy pollutions most likely derive from the accretion of terrestrial-type planet(esimal)s. For each system, the minimum accreted mass is ~1022 g, that of a large asteroid. In PG1…
Solar Wind Modeling with Turbulence Transport and Heating
Matthaeus, William H.; Goldstein, Melvyn L.; Usmanov, Arcadi V. +1 more
We have developed an axisymmetric steady-state solar wind model that describes properties of the large-scale solar wind, interplanetary magnetic field, and turbulence throughout the heliosphere from 0.3 AU to 100 AU. The model is based on numerical solutions of large-scale Reynolds-averaged magnetohydrodynamic equations coupled with a set of small…
Morphology and Size Differences Between Local and High-redshift Luminous Infrared Galaxies
Juneau, Stéphanie; Rieke, George H.; Eisenstein, Daniel J. +1 more
We show that the star-forming regions in high-redshift luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) and submillimeter galaxies (SMGs) have similar physical scales to those in local normal star-forming galaxies. To first order, their higher infrared (IR) luminosities result from higher luminosity surface density. We also find a g…
X-ray Emission from Optically Selected Radio-intermediate and Radio-loud Quasars
Brandt, W. N.; Schneider, D. P.; Miller, B. P. +3 more
We present the results of an investigation into the X-ray properties of radio-intermediate and radio-loud quasars (RIQs and RLQs, respectively). We combine large, modern optical (e.g., SDSS) and radio (e.g., FIRST) surveys with archival X-ray data from Chandra, XMM-Newton, and ROSAT to generate an optically selected sample that includes 188 RIQs a…
The First Measurement of the Adiabatic Index in the Solar Corona Using Time-dependent Spectroscopy of Hinode/EIS Observations
Del Zanna, Giulio; Van Doorsselaere, Tom; Nakariakov, Valery M. +3 more
We use observations of a slow magnetohydrodynamic wave in the corona to determine for the first time the value of the effective adiabatic index, using data from the Extreme-ultraviolet Imaging Spectrometer on board Hinode. We detect oscillations in the electron density, using the CHIANTI atomic database to perform spectroscopy. From the time-depen…
Two Components of the Solar Coronal Emission Revealed by Extreme-ultraviolet Spectroscopic Observations
Martínez-Sykora, Juan; De Pontieu, Bart; Wang, Xin +3 more
Recent spectroscopic observations have revealed the ubiquitous presence of blueward asymmetries of emission lines formed in the solar corona and transition region. These asymmetries are most prominent in loop footpoint regions, where a clear correlation of the asymmetry with the Doppler shift and line width determined from the single-Gaussian fit …
The Dark Matter Distribution in A383: Evidence for a Shallow Density Cusp from Improved Lensing, Stellar Kinematic, and X-ray Data
Treu, Tommaso; Ellis, Richard S.; Newman, Andrew B. +1 more
We extend our analyses of the dark matter (DM) distribution in relaxed clusters to the case of A383, a luminous X-ray cluster at z = 0.189 with a dominant central galaxy and numerous strongly lensed features. Following our earlier papers, we combine strong and weak lensing constraints secured with Hubble Space Telescope and Subaru imaging with the…
Constraints on the Heating of High-temperature Active Region Loops: Observations from Hinode and the Solar Dynamics Observatory
Winebarger, Amy R.; Warren, Harry P.; Brooks, David H.
We present observations of high-temperature emission in the core of a solar active region using instruments on Hinode and the Solar Dynamics Observatory (SDO). These multi-instrument observations allow us to determine the distribution of plasma temperatures and follow the evolution of emission at different temperatures. We find that at the apex of…