Search Publications
Isochrones for Old (>5 Gyr) Stars and Stellar Populations. I. Models for -2.4 <= [Fe/H] <=+0.6, 0.25 <= Y <= 0.33, and -0.4 <= [α/Fe] <=+0.4
Edvardsson, Bengt; VandenBerg, Don A.; Ferguson, Jason W. +1 more
Canonical grids of stellar evolutionary sequences have been computed for the helium mass-fraction abundances Y = 0.25, 0.29, and 0.33, and for iron abundances that vary from -2.4 to +0.4 (in 0.2 dex increments) when [α/Fe] =+0.4, or for the ranges -2.0 <= [Fe/H] <=+0.6, -1.8 <= [Fe/H] <=+0.6 when [α/Fe] =0.0 and -0.4, respectively. The…
NuSTAR Discovery of a Luminosity Dependent Cyclotron Line Energy in Vela X-1
Hailey, Charles J.; Fürst, Felix; Pottschmidt, Katja +13 more
We present NuSTAR observations of Vela X-1, a persistent, yet highly variable, neutron star high-mass X-ray binary (HMXB). Two observations were taken at similar orbital phases but separated by nearly a year. They show very different 3-79 keV flux levels as well as strong variability during each observation, covering almost one order of magnitude …
Three-fluid, Three-dimensional Magnetohydrodynamic Solar Wind Model with Eddy Viscosity and Turbulent Resistivity
Matthaeus, William H.; Goldstein, Melvyn L.; Usmanov, Arcadi V.
We have developed a three-fluid, three-dimensional magnetohydrodynamic solar wind model that incorporates turbulence transport, eddy viscosity, turbulent resistivity, and turbulent heating. The solar wind plasma is described as a system of co-moving solar wind protons, electrons, and interstellar pickup protons, with separate energy equations for …
Structures of Interplanetary Magnetic Flux Ropes and Comparison with Their Solar Sources
Qiu, Jiong; Hu, Qiang; Dasgupta, B. +2 more
Whether a magnetic flux rope is pre-existing or formed in situ in the Sun's atmosphere, there is little doubt that magnetic reconnection is essential to release the flux rope during its ejection. During this process, the question remains: how does magnetic reconnection change the flux-rope structure? In this work, we continue with the original stu…
Modeling the Formation of Globular Cluster Systems in the Virgo Cluster
Li, Hui; Gnedin, Oleg Y.
The mass distribution and chemical composition of globular cluster (GC) systems preserve fossil record of the early stages of galaxy formation. The observed distribution of GC colors within massive early-type galaxies in the ACS Virgo Cluster Survey (ACSVCS) reveals a multi-modal shape, which likely corresponds to a multi-modal metallicity distrib…
On the prevalence of small-scale twist in the solar chromosphere and transition region
Golub, L.; Tian, H.; De Pontieu, B. +21 more
The solar chromosphere and transition region (TR) form an interface between the Sun’s surface and its hot outer atmosphere. There, most of the nonthermal energy that powers the solar atmosphere is transformed into heat, although the detailed mechanism remains elusive. High-resolution (0.33-arc second) observations with NASA’s Interface Region Imag…
PACS photometry of the Herschel Reference Survey - far-infrared/submillimetre colours as tracers of dust properties in nearby galaxies
Ciesla, L.; Buat, V.; Boquien, M. +26 more
We present Herschel/PACS 100 and 160 µm integrated photometry for the 323 galaxies in the Herschel Reference Survey (HRS), a K-band, volume-limited sample of galaxies in the local Universe. Once combined with the Herschel/SPIRE observations already available, these data make the HRS the largest representative sample of nearby galaxies with h…
The evolution of dust-obscured star formation activity in galaxy clusters relative to the field over the last 9 billion years
Weiner, Benjamin J.; Moustakas, John; Dey, Arjun +14 more
We compare the star formation (SF) activity in cluster galaxies to the field from z = 0.3 to 1.5 using Herschel Spectral and Photometric Imaging REceiver 250 µm imaging and utilizing 274 clusters from the IRAC Shallow Cluster Survey (ISCS). These clusters were selected as rest-frame near-infrared overdensities over the 9 square degree Boötes…
Computing the reconnection rate in turbulent kinetic layers by using electron mixing to identify topology
Daughton, W.; Nakamura, T. K. M.; Karimabadi, H. +2 more
Three-dimensional kinetic simulations of magnetic reconnection for parameter regimes relevant to the magnetopause current layer feature the development of turbulence, driven by the magnetic and velocity shear, and dominated by coherent structures including flux ropes, current sheets, and flow vortices. Here, we propose a new approach for computing…
Planck 2013 results. VII. HFI time response and beams
Kneissl, R.; Miville-Deschênes, M. -A.; Bernard, J. -P. +220 more
This paper characterizes the effective beams, the effective beam window functions and the associated errors for the Planck High Frequency Instrument (HFI) detectors. The effective beam is theangular response including the effect of the optics, detectors, data processing and the scan strategy. The window function is the representation of this beam …