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The perihelion activity of comet 67P/Churyumov-Gerasimenko as seen by robotic telescopes
Meech, Karen J.; Snodgrass, Colin; Lister, Tim +13 more
Around the time of its perihelion passage, the observability of 67P/Churyumov-Gerasimenko from Earth was limited to very short windows each morning from any given site, due to the low solar elongation of the comet. The peak in the comet's activity was therefore difficult to observe with conventionally scheduled telescopes, but was possible where s…
The tectonics of Titan: Global structural mapping from Cassini RADAR
Kirk, Randolph L.; Lorenz, Ralph D.; Neish, Catherine D. +5 more
The Cassini RADAR mapper has imaged elevated mountain ridge belts on Titan with a linear-to-arcuate morphology indicative of a tectonic origin. Systematic geomorphologic mapping of the ridges in Synthetic Aperture RADAR (SAR) images reveals that the orientation of ridges is globally E-W and the ridges are more common near the equator than the pole…
The Molecular Clouds Fueling A 1/5 Solar Metallicity Starburst
Leroy, Adam K.; Johnson, Kelsey E.; Sandstrom, Karin +2 more
Using the Atacama Large Millimeter/submillimeter Array, we have made the first high spatial and spectral resolution observations of the molecular gas and dust in the prototypical blue compact dwarf galaxy II Zw 40. The {}12{CO}(2-1) and {}12{CO}(3-2) emission is clumpy and distributed throughout the central star-forming regio…
An HST/COS legacy survey of intervening Si III absorption in the extended gaseous halos of low-redshift galaxies
Wakker, B. P.; Fechner, C.; Richter, P. +3 more
Aims: Doubly ionized silicon (Si III) is a powerful tracer of diffuse ionized gas inside and outside of galaxies. It can be observed in the local Universe in ultraviolet (UV) absorption against bright extragalactic background sources. We here present an extensive study of intervening Si III-selected absorbers and study the properties of the w…
Hinode and IRIS Observations of the Magnetohydrodynamic Waves Propagating from the Photosphere to the Chromosphere in a Sunspot
Shimizu, Toshifumi; Imada, Shinsuke; Kanoh, Ryuichi
Magnetohydrodynamic (MHD) waves have been considered as energy sources for heating the solar chromosphere and the corona. Although MHD waves have been observed in the solar atmosphere, there are a lack of quantitative estimates on the energy transfer and dissipation in the atmosphere. We performed simultaneous Hinode and Interface Region Imaging S…
Properties of the cluster population of NGC 1566 and their implications
Bastian, N.; Ryon, J. E.; Adamo, A. +2 more
We present results of a photometric study into the cluster population of NGC 1566, a nearby grand design spiral galaxy, sampled out to a Galactocentric radius of ≈5.5 kpc. The shape of the mass-limited age distribution shows negligible variation with radial distance from the centre of the galaxy, and demonstrates three separate sections, with a st…
The Lyman alpha reference sample. VI. Lyman alpha escape from the edge-on disk galaxy Mrk 1486
Verhamme, Anne; Cannon, John M.; Hayes, Matthew +16 more
Context. Recent numerical simulations suggest that the strength of the Lyman alpha (Lyα) line of star-forming disk galaxies strongly depends on the inclination at which they are observed: from edge-on to face-on, we expect to see a change from a strongly attenuated Lyα line to a strong Lyα emission line.
Aims: We aim to understand how a stron…
The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447. I. The X-ray View
Gehrels, N.; Wilms, J.; Kadler, M. +11 more
As part of the TANAMI multiwavelength progam, we discuss new X-ray observations of the γ-ray and radio-loud narrow line Seyfert 1 galaxy (γ-NLS1) PKS 2004-447. The active galaxy is a member of a small sample of radio-loud NLS1s detected in γ-rays by the Fermi Large Area Telescope. It stands out for being the radio-loudest and the only southern-hem…
Searching in the dark: the dark mass content of the Milky Way globular clusters NGC288 and NGC6218
Dalessandro, E.; Mucciarelli, A.; Origlia, L. +8 more
We present an observational estimate of the fraction and distribution of dark mass in the innermost region of the two Galactic globular clusters NGC 6218 (M12) and NGC 288. Such an assessment has been made by comparing the dynamical and luminous mass profiles derived from an accurate analysis of the most extensive spectroscopic and photometric sur…
New Orbits Based on Speckle Interferometry at SOAR
Tokovinin, Andrei
The orbits of 55 visual binary stars are computed using recent speckle interferometry data from the SOAR telescope: 33 first-time orbits and 22 revisions of previous orbit calculations. The orbital periods range from 1.4-370 years, and the quality of the orbits ranges from definitive to preliminary and tentative. Most binaries consist of low-mass …