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Chorus wave-normal statistics in the Earth's radiation belts from ray tracing technique
Krasnoselskikh, V.; Breuillard, H.; Agapitov, O. +3 more
Discrete ELF/VLF (Extremely Low Frequency/Very Low Frequency) chorus emissions are one of the most intense electromagnetic plasma waves observed in radiation belts and in the outer terrestrial magnetosphere. These waves play a crucial role in the dynamics of radiation belts, and are responsible for the loss and the acceleration of energetic electr…
The North Ecliptic Pole Wide survey of AKARI: a near- and mid-infrared source catalog
Im, M.; Lee, H. M.; White, G. J. +19 more
We present a photometric catalog of infrared (IR) sources based on the North Ecliptic Pole Wide field (NEP-Wide) survey of AKARI, which is an infrared space telescope launched by Japan. The NEP-Wide survey covered 5.4 deg2 area, a nearly circular shape centered on the NEP, using nine photometric filter-bands from 2-25 µm of the In…
Active Learning to Overcome Sample Selection Bias: Application to Photometric Variable Star Classification
Miller, Adam A.; Bloom, Joshua S.; Richards, Joseph W. +6 more
Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived fr…
Predictions of Energy and Helicity in Four Major Eruptive Solar Flares
Qiu, Jiong; Longcope, Dana W.; Kazachenko, Maria D. +1 more
In order to better understand the solar genesis of interplanetary magnetic clouds (MCs), we model the magnetic and topological properties of four large eruptive solar flares and relate them to observations. We use the three-dimensional Minimum Current Corona model (Longcope, 1996, Solar Phys.169, 91) and observations of pre-flare photospheric magn…
Ammonia clathrate hydrates as new solid phases for Titan, Enceladus, and other planetary systems
Kumar, R.; Shin, K.; Udachin, K. A. +2 more
Are Solar Active Regions with Major Flares More Fractal, Multifractal, or Turbulent Than Others?
Georgoulis, Manolis K.
Multiple recent investigations of solar magnetic-field measurements have raised claims that the scale-free (fractal) or multiscale (multifractal) parameters inferred from the studied magnetograms may help assess the eruptive potential of solar active regions, or may even help predict major flaring activity stemming from these regions. We investiga…
Carbon-rich Dust Production in Metal-poor Galaxies in the Local Group
van Loon, J. Th.; Wood, P. R.; Zijlstra, A. A. +7 more
We have observed a sample of 19 carbon stars in the Sculptor, Carina, Fornax, and Leo I dwarf spheroidal galaxies with the Infrared Spectrograph on the Spitzer Space Telescope. The spectra show significant quantities of dust around the carbon stars in Sculptor, Fornax, and Leo I, but little in Carina. Previous comparisons of carbon stars with simi…
Spatial variation of the cooling lines in the Orion Bar from Herschel/PACS
Abergel, A.; Bernard, J. -P.; White, G. J. +8 more
Context. The energetics in photo-dissociation regions (PDRs) are mainly regulated by the balance between the heating from the photo-electric effect acting on dust grains, and the cooling via the copious emission of photons in far-infrared lines. The Orion Bar is a luminous and nearby PDR, which presents to the observer an ideal edge-on orientation…
The dust and gas properties of M83
Clements, D. L.; Boquien, M.; Roussel, H. +17 more
We examine the dust and gas properties of the nearby, barred galaxy M83, which is part of the Very Nearby Galaxy Survey. Using images from the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging REceiver (SPIRE) instruments of Herschel, we examine the dust temperature and dust mass surface density distribution. …
Thermal Properties of a Solar Coronal Cavity Observed with the X-Ray Telescope on Hinode
Reeves, Katharine K.; Gibson, Sarah E.; Kucera, Therese A. +2 more
Coronal cavities are voids in coronal emission often observed above high latitude filament channels. Sometimes, these cavities have areas of bright X-ray emission in their centers. In this study, we use data from the X-ray Telescope (XRT) on the Hinode satellite to examine the thermal emission properties of a cavity observed during 2008 July that …