Search Publications
Empirical Constraints on Proton and Electron Heating in the Fast Solar Wind
Cranmer, Steven R.; Kasper, Justin C.; Matthaeus, William H. +1 more
We analyze measured proton and electron temperatures in the high-speed solar wind in order to calculate the separate rates of heat deposition for protons and electrons. When comparing with other regions of the heliosphere, the fast solar wind has the lowest density and the least frequent Coulomb collisions. This makes the fast wind an optimal test…
Velocity Characteristics of Evaporated Plasma Using Hinode/EUV Imaging Spectrometer
Milligan, Ryan O.; Dennis, Brian R.
This paper presents a detailed study of chromospheric evaporation using the EUV Imaging Spectrometer (EIS) onboard Hinode in conjunction with hard X-ray (HXR) observations from Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). The advanced capabilities of EIS were used to measure Doppler shifts in 15 emission lines covering the temper…
The Spatially Resolved Star Formation Law From Integral Field Spectroscopy: VIRUS-P Observations of NGC 5194
Blanc, Guillermo A.; Gebhardt, Karl; Evans, Neal J., II +2 more
We investigate the relation between the star formation rate (SFR) surface density (ΣSFR) and the mass surface density of gas (Σgas) in NGC 5194 (a.k.a. M51a, Whirlpool Galaxy). Visible Integral field Replicable Unit Spectrograph Prototype (VIRUS-P) integral field spectroscopy of the central 4.1 × 4.1 kpc2 of the ga…
On the Weakening of the Polar Magnetic Fields during Solar Cycle 23
Sheeley, N. R., Jr.; Wang, Y. -M.; Robbrecht, E.
The Sun's polar fields are currently ~40% weaker than they were during the previous three sunspot minima. This weakening has been accompanied by a corresponding decrease in the interplanetary magnetic field (IMF) strength, by a ~20% shrinkage in the polar coronal-hole areas, and by a reduction in the solar-wind mass flux over the poles. It has als…
Two distinct sequences of blue straggler stars in the globular cluster M 30
Dalessandro, E.; Beccari, G.; Ferraro, F. R. +7 more
Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history. `Blue stragglers' are stars massive enough that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for their formation: mass transfer between binary companions and stellar mergers result…
Modeling and Reproducibility of Suzaku HXD PIN/GSO Background
Isobe, Naoki; Enoto, Teruaki; Yamaoka, Kazutaka +27 more
Suzaku Hard X-ray Detector (HXD) achieved the lowest background level than any other previously or currently operational missions sensitive in the energy range of 10--600keV, by utilizing PIN photodiodes and GSO scintillators mounted in BGO active shields to reject particle background and Compton-scattered events as much as possible. Because it do…
Driving major solar flares and eruptions: A review
Schrijver, Carolus J.
This review focuses on the processes that energize and trigger M- and X-class solar flares and associated flux-rope destabilizations. Numerical modeling of specific solar regions is hampered by uncertain coronal-field reconstructions and by poorly understood magnetic reconnection; these limitations result in uncertain estimates of field topology, …
OGLE-2005-BLG-071Lb, the Most Massive M Dwarf Planetary Companion?
Bennett, D. P.; Cook, K. H.; Gal-Yam, A. +85 more
We combine all available information to constrain the nature of OGLE-2005-BLG-071Lb, the second planet discovered by microlensing and the first in a high-magnification event. These include photometric and astrometric measurements from the Hubble Space Telescope, as well as constraints from higher order effects extracted from the ground-based light…
Evolution of the Color-Magnitude Relation in Galaxy Clusters at z ~ 1 from the ACS Intermediate Redshift Cluster Survey
Franx, Marijn; Illingworth, Garth D.; Postman, Marc +10 more
We apply detailed observations of the color-magnitude relation (CMR) with the Advanced Camera for Surveys on the Hubble Space Telescope to study galaxy evolution in eight clusters at z≈ 1. The early-type red sequence is well defined and elliptical and lenticular galaxies lie on similar CMRs. We analyze CMR parameters—scatter, slope, and zero point…
New multiply-lensed galaxies identified in ACS/NIC3 observations of Cl0024+1654 using an improved mass model
Broadhurst, Tom; Zheng, Wei; Zitrin, Adi +9 more
We present an improved strong-lensing analysis of Cl0024+1654 (z = 0.39) using deep Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS)/NIC3 images, based on 33 multiply-lensed images of 11 background galaxies. These are found with a model that assumes mass approximately traces light, with a low-order expansion to allow for flexibility …