Search Publications
Active Region Loops: Hinode/Extreme-Ultraviolet Imaging Spectrometer Observations
Young, Peter R.; Dwivedi, Bhola N.; Tripathi, Durgesh +2 more
We have carried out a study of active region loops using observations from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode using 1'' raster data for an active region observed on 2007 May 19. We find that active region structures which are clearly discernible in cooler lines (≈1 MK) become "fuzzy" at higher temperatures (≈2 MK). …
Oblique propagation of whistler mode waves in the chorus source region
Gurnett, D. A.; Pickett, J. S.; Santolík, O. +2 more
Whistler mode chorus has been shown to play a role in the process of local acceleration of electrons in the outer Van Allen radiation belt. Most of the quasi-linear and nonlinear theoretical studies assume that the waves propagate parallel to the terrestrial magnetic field. We show a case where this assumption is invalid. We use data from the Clus…
The Lyman Alpha Morphology of Local Starburst Galaxies: Release of Calibrated Images
Hayes, Matthew; Östlin, Göran; Leitherer, Claus +4 more
We present reduced and calibrated high resolution Lyman-alpha (Lyα) images for a sample of six local star-forming galaxies. Targets were selected to represent a range in luminosity and metallicity and to include both known Lyα emitters and nonemitters. Far ultraviolet imaging was carried out with the Solar Blind Channel of the Advanced Camera for …
Bulk properties of the slow and fast solar wind and interplanetary coronal mass ejections measured by Ulysses: Three polar orbits of observations
McComas, D. J.; Forsyth, R. J.; Gosling, J. T. +2 more
We examined plasma and magnetic field observations from all three Ulysses polar orbits of the Sun to study the properties of the slow and fast solar wind and interplanetary coronal mass ejections (ICMEs). We derived equations to characterize the radial and latitudinal variations for these three types of heliospheric plasma and identify distinguish…
HESS J0632+057: A New Gamma-Ray Binary?
Funk, S.; Reimer, O.; Dubus, G. +8 more
The High Energy Stereoscopic System (HESS) survey of the Galactic plane has established the existence of a substantial number (~ 40) of Galactic TeV γ-ray sources, a large fraction of which remain unidentified. HESS J0632+057 is one of a small fraction of these objects, which is point-like in nature (<2' rms), and is one of only two point-like …
First Determination of the True Mass of Coronal Mass Ejections: A Novel Approach to Using the Two STEREO Viewpoints
Vourlidas, Angelos; Colaninno, Robin C.
The twin Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) COR2 coronagraphs of the Solar Terrestrial Relations Observatory (STEREO) provide images of the solar corona from two viewpoints in the solar system. Since their launch in late 2006, the STEREO Ahead (A) and Behind (B) spacecraft have been slowly separating from Earth at…
The Hubble Sequence Beyond z = 2 for Massive Galaxies: Contrasting Large Star-forming and Compact Quiescent Galaxies
van Dokkum, Pieter G.; Franx, Marijn; Illingworth, Garth D. +2 more
We present Hubble Space Telescope NIC2 morphologies of a spectroscopic sample of massive galaxies at z ~ 2.3 by extending our sample of 9 compact quiescent galaxies (re ~ 0.9 kpc) with 10 massive emission-line galaxies. The emission-line galaxies are classified by the nature of their ionized emission; there are six star-forming galaxies…
The XMM-Newton long look of NGC 1365: uncovering of the obscured X-ray source
Zezas, A.; Bianchi, S.; Guainazzi, M. +10 more
We present an analysis of the extreme obscuration variability observed during an XMM-Newton 5-d continuous monitoring of the active galactic nuclei (AGN) in NGC 1365. The source was in a reflection-dominated state in the first ~1.5 d, then a strong increase in the 7-10 keV emission was observed in ~10 h, followed by a symmetric decrease. The spect…
Orbits and Masses of the Satellites of the Dwarf Planet Haumea (2003 EL61)
Ragozzine, D.; Brown, M. E.
Using precise relative astrometry from the Hubble Space Telescope and the W. M. Keck Telescope, we have determined the orbits and masses of the two dynamically interacting satellites of the dwarf planet (136108) Haumea, formerly 2003 EL61. The orbital parameters of Hi'iaka, the outer, brighter satellite, match well the previously derived orbit. On…
Chemical enrichment in the cluster of galaxies Hydra A
Finoguenov, A.; Böhringer, H.; Simionescu, A. +4 more
We analyzed global properties, radial profiles, and 2D maps of the metal abundances and temperature in the cool core cluster of galaxies Hydra A using a deep ~120 ks XMM-Newton exposure. The best fit among the available spectral models is provided by a Gaussian distribution of the emission measure (gdem). We can accurately determine abundances for…