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The Origin and Evolution of Metallicity Gradients: Probing the Mode of Mass Assembly at z ~= 2
Richard, Johan; Ellis, Richard S.; Jones, Tucker +1 more
We present and discuss measurements of the gas-phase metallicity gradient in four gravitationally lensed galaxies at z = 2.0-2.4 based on adaptive optics-assisted imaging spectroscopy with the Keck II telescope. Three galaxies with well-ordered rotation reveal metallicity gradients with lower gas-phase metallicities at larger galactocentric radii.…
Scaling of the Electron Dissipation Range of Solar Wind Turbulence
Belmont, G.; Sahraoui, F.; Huang, S. Y. +4 more
Electron scale solar wind (SW) turbulence has attracted great interest in recent years. Considerable evidence exists that the turbulence is not fully dissipated near the proton scale, but continues cascading down to electron scales. However, the scaling of the magnetic energy spectra as well as the nature of the plasma modes involved at those smal…
Particle acceleration in dipolarization events
Nakamura, R.; Hesse, M.; Birn, J. +1 more
Using the electromagnetic fields of a recent MHD simulation of magnetotail reconnection, flow bursts and dipolarization, we investigate the acceleration of test particles (protons and electrons) to suprathermal energies, confirming and extending earlier results on acceleration mechanisms and sources. (Part of the new results have been reviewed rec…
A review of pressure anisotropy caused by electron trapping in collisionless plasma, and its implications for magnetic reconnection
Daughton, William; Egedal, Jan; Le, Ari
From spacecraft data, it is evident that electron pressure anisotropy develops in collisionless plasmas. This is in contrast to the results of theoretical investigations, which suggest this anisotropy should be limited. Common for such theoretical studies is that the effects of electron trapping are not included; simply speaking, electron trapping…
Sequence of infilling events in Gale Crater, Mars: Results from morphology, stratigraphy, and mineralogy
Le Deit, Laetitia; Hauber, Ernst; Jaumann, Ralf +3 more
Crater is filled by sedimentary deposits including a mound of layered deposits, Aeolis Mons. Using orbital data, we mapped the crater infillings and measured their geometry to determine their origin. The sediment of Aeolis Mons is interpreted to be primarily air fall material such as dust, volcanic ash, fine-grained impact products, and possibly s…
Planck intermediate results. IX. Detection of the Galactic haze with Planck
Bernard, J. -P.; Planck Collaboration; Ade, P. A. R. +186 more
Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterise the emission from the Galactic "haze" at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to | b | ~ 35-50° in Galactic latitud…
3D model of hydrogen atmospheric escape from HD 209458b and HD 189733b: radiative blow-out and stellar wind interactions
Lecavelier des Etangs, A.; Bourrier, V.
Transit observations in the Lyman-α line of the hot-Jupiters HD 209458b and HD 189733b revealed strong signatures of neutral hydrogen escaping the planets' upper atmospheres. Here we present a 3D particle model of the dynamics of the escaping atoms. This model is used to calculate theoretical Lyman-α absorption line profiles, which can be directly…
The multi-thermal emission in solar active regions
Del Zanna, G.
We present simultaneous SDO AIA and Hinode EIS observations of the hot cores of active regions (ARs) and assess the dominant contributions to the AIA EUV bands. This is an extension of our previous work. We find good agreement between SDO AIA, EVE and EIS observations, using our new EIS calibration and the latest EVE v.3 data. We find that all the…
A Refined Estimate of the Ionizing Emissivity from Galaxies at z ~= 3: Spectroscopic Follow-up in the SSA22a Field
Siana, Brian; Shapley, Alice E.; Steidel, Charles C. +2 more
We investigate the contribution of star-forming galaxies to the ionizing background at z ~ 3, building on previous work based on narrowband (NB3640) imaging in the SSA22a field. We use new Keck/LRIS spectra of Lyman break galaxies (LBGs) and narrowband-selected Lyα emitters (LAEs) to measure redshifts for 16 LBGs and 87 LAEs at z > 3.055, such …
The UV and X-ray activity of the M dwarfs within 10 pc of the Sun
Liefke, C.; Micela, G.; Marino, A. +2 more
M dwarfs are the most numerous stars in the Galaxy. They are characterized by strong magnetic activity. The ensuing high-energy emission is crucial for the evolution of their planets and the eventual presence of life on them. We systematically study the X-ray and ultraviolet emission of a subsample of M dwarfs from a recent proper-motion survey, s…