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Superthermal electron magnetosphere-ionosphere coupling in the diffuse aurora in the presence of ECH waves
Glocer, A.; Sibeck, D. G.; Singhal, R. P. +3 more
There are two main theories for the origin of the diffuse auroral electron precipitation: first, pitch angle scattering by electrostatic electron cyclotron harmonic (ECH) waves, and second, by whistler mode waves. Precipitating electrons initially injected from the plasma sheet to the loss cone via wave-particle interaction processes degrade in th…
A novel sparse boosting method for crater detection in the high resolution planetary image
Wang, Yan; Yang, Gang; Guo, Lei
Impact craters distributed on planetary surface become one of the main barriers during the soft landing of planetary probes. In order to accelerate the crater detection, in this paper, we present a new sparse boosting (SparseBoost) method for automatic detection of sub-kilometer craters. The SparseBoost method integrates an improved sparse kernel …
Far-UV phase dependence and surface characteristics of comet 67P/Churyumov-Gerasimenko as observed with Rosetta Alice
Stern, S. A.; Feldman, P. D.; Bertaux, J. -L. +7 more
Aims. The Alice far-ultraviolet (FUV) spectrograph onboard Rosetta has, for the first time, imaged the surface of a comet, 67P/Churyumov-Gerasimenko (67P), in the FUV. With spatially resolved data, the nucleus properties are characterized in the FUV, including phase dependence, albedo, and spectral slope. Regional measurements across the nucleus a…
NGC 1266: Characterization of the Nuclear Molecular Gas in an Unusual SB0 Galaxy
Glenn, J.; Maloney, P. R.; Rangwala, N. +1 more
With a substantial nuclear molecular gas reservoir and broad, high-velocity CO molecular line wings previously interpreted as an outflow, NGC 1266 is a rare SB0 galaxy. Previous analyses of interferometry, spectrally resolved low-J CO emission lines, and unresolved high-J emission lines have established basic properties of the molecular gas and th…
HST+COS spectra of the double white dwarf CSS 41177 place the secondary inside the pulsational instability strip
Gänsicke, B. T.; Marsh, T. R.; Parsons, S. G. +1 more
We present Hubble Space Telescope + Cosmic Origins Spectrograph (HST+COS) data of the eclipsing double white dwarf binary CSS 41177. Due to the temperature difference between the two white dwarfs, the HST+COS far-ultraviolet data are dominated by the hot, primary white dwarf and allow us to precisely measure its temperature (T1). Using …
The role of ion-neutral collisions in Titan's magnetospheric interaction
Sillanpää, Ilkka; Johnson, Robert E.
We have studied the effects of ion-neutral collisions on Titan's interaction with the magnetospheric plasma flow and also on the Alfvén wings formed in this super-Alfvénic interaction. We have used the HYB-Titan hybrid simulation model to study the role of charge exchange processes and elastic ion collisions in the interaction region. The simulati…
Constraining the intracluster pressure profile from the thermal SZ power spectrum
Bertoldi, F.; Pacaud, F.; Ramos-Ceja, M. E. +1 more
The angular power spectrum of the thermal Sunyaev-Zel'dovich (tSZ) effect is highly sensitive to cosmological parameters such as σ8 and Ωm, but its use as a precision cosmological probe is hindered by the astrophysical uncertainties in modeling the gas pressure profile in galaxy groups and clusters. In this paper we assume th…
Acceleration of ions and nano dust at a comet in the solar wind
Kallio, E.; Gunell, H.; Nilsson, H. +6 more
A quasi-neutral hybrid simulation of the interaction of the solar wind with the atmosphere of a comet is used together with a test particle simulation of cometary ions and dust to compute trajectories and velocity distribution functions of charged particles, starting outside the diamagnetic cavity at 150 km cometocentric distance. The simulations …
Relative Abundance Measurements in Plumes and Interplumes
Hahn, M.; Savin, D. W.; Guennou, C.
We present measurements of relative elemental abundances in plumes and interplumes. Plumes are bright, narrow structures in coronal holes that extend along open magnetic field lines far out into the corona. Previous work has found that in some coronal structures the abundances of elements with a low first ionization potential (FIP) <10 eV are e…
Intrinsic colour indices of Be stars obtained from 2MASS photometry
Wegner, W.
This paper is based on 2MASS photometry (JHK_s magnitudes) of 1172 Be stars. The observed mean intrinsic colours have been derived with aid of two-colour diagrams for Be stars of luminosity classes Ie-IIe, IIIe and IVe-Ve. The obtained results are the first determinations of their intrinsic colours in the astronomical literature. The smoothed infr…