Search Publications
Solar EUV Experiment (SEE): Mission overview and first results
Chamberlin, Phillip C.; Woods, Thomas N.; Eparvier, Francis G. +6 more
The Solar EUV Experiment (SEE) is one of four scientific instruments on the NASA Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) spacecraft, which has been simultaneously observing the Sun and Earth's upper atmosphere since January 2002. The SEE instrument measures the irradiance of the highly variable, solar extreme ultraviolet (EU…
On the Generation, Propagation, and Reflection of Alfvén Waves from the Solar Photosphere to the Distant Heliosphere
Cranmer, S. R.; van Ballegooijen, A. A.
We present a comprehensive model of the global properties of Alfvén waves in the solar atmosphere and the fast solar wind. Linear non-WKB wave transport equations are solved from the photosphere to a distance past the orbit of the Earth, and for wave periods ranging from 3 s to 3 days. We derive a radially varying power spectrum of kinetic and mag…
Biosignatures from Earth-Like Planets Around M Dwarfs
Crisp, David; Cohen, Martin; Tinetti, Giovanna +5 more
Coupled one-dimensional photochemical-climate calculations have been performed for hypothetical Earth-like planets around M dwarfs. Visible/near-infrared and thermal-infrared synthetic spectra of these planets were generated to determine which biosignature gases might be observed by a future, space-based telescope. Our star sample included two obs…
The Cosmic Evolution of Hard X-Ray-selected Active Galactic Nuclei
Yang, Y.; Capak, P.; Wang, W. -H. +4 more
We use highly spectroscopically complete deep and wide-area Chandra surveys to determine the cosmic evolution of hard X-ray-selected active galactic nuclei (AGNs). For the deep fields, we supplement the spectroscopic redshifts with photometric redshifts to assess where the unidentified sources are likely to lie. We find that the median redshifts a…
New Mass-Loss Measurements from Astrospheric Lyα Absorption
Linsky, J. L.; Redfield, S.; Zank, G. P. +2 more
Measurements of stellar mass-loss rates are used to assess how wind strength varies with coronal activity and age for solar-like stars. Mass loss generally increases with activity, but we find evidence that winds suddenly weaken at a certain activity threshold. Very active stars are often observed to have polar starspots, and we speculate that the…
Star Formation in NGC 5194 (M51a): The Panchromatic View from GALEX to Spitzer
Helou, G.; Roussel, H.; Leitherer, C. +32 more
Far-ultraviolet to far-infrared images of the nearby galaxy NGC 5194 (M51a), from a combination of space-based (Spitzer, GALEX, and Hubble Space Telescope) and ground-based data, are used to investigate local and global star formation and the impact of dust extinction. The Spitzer data provide unprecedented spatial detail in the infrared, down to …
A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)
Lépine, Sébastien; Shara, Michael M.
The LSPM catalog is a comprehensive list of 61,977 stars north of the J2000 celestial equator that have proper motions larger than 0.15" yr-1 (local-background-stars frame). The catalog has been generated primarily as a result of our systematic search for high proper motion stars in the Digitized Sky Surveys using our SUPERBLINK softwar…
Discovery of the binary pulsar PSR B1259-63 in very-high-energy gamma rays around periastron with HESS
Raux, J.; Ripken, J.; Funk, S. +99 more
We report the discovery of very-high-energy (VHE) γ-ray emission of the binary system
Shock Geometry, Seed Populations, and the Origin of Variable Elemental Composition at High Energies in Large Gradual Solar Particle Events
Cohen, C. M. S.; Mewaldt, R. A.; Maclennan, C. G. +5 more
Above a few tens of MeV per nucleon, large, gradual solar energetic particle (SEP) events are highly variable in their spectral characteristics and elemental composition. The origin of this variability has been a matter of intense and ongoing debate. In this paper, we propose that this variability arises from the interplay of two factors-shock geo…
The Morphology-Density Relation in z ~ 1 Clusters
Ford, H. C.; Demarco, R.; Infante, L. +39 more
We measure the morphology-density relation (MDR) and morphology-radius relation (MRR) for galaxies in seven z~1 clusters that have been observed with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope. Simulations and independent comparisons of our visually derived morphologies indicate that ACS allows one to distinguish bet…