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The Trace of the CNO Cycle in the Ring Nebula NGC 6888
Morisset, C.; Bresolin, F.; García-Rojas, J. +3 more
We present new results on the chemical composition of the Galactic ring nebula NGC 6888 surrounding the WN6(h) star WR136. The data are based on deep spectroscopical observations taken with the High Dispersion Spectrograph at the 8.2 m Subaru Telescope. The spectra cover the optical range from 3700 to 7400 Å. The effect of the CNO cycle is well-id…
The Ultraviolet Attenuation Law in Backlit Spiral Galaxies
Holwerda, Benne W.; Schawinski, Kevin; Keel, William C. +2 more
The effective extinction law (attenuation behavior) in galaxies in the emitted ultraviolet (UV) regime is well known only for actively star-forming objects and combines effects of the grain properties, fine structure in the dust distribution, and relative distributions of stars and dust. We use Galaxy Evolution Explorer, XMM Optical Monitor, and H…
Insights into Titan's geology and hydrology based on enhanced image processing of Cassini RADAR data
Lucas, Antoine; Aharonson, Oded; Hayes, Alexander G. +3 more
The Cassini Synthetic Aperture Radar has been acquiring images of Titan's surface since October 2004. To date, 59% of Titan's surface has been imaged by radar, with significant regions imaged more than once. Radar data suffer from speckle noise hindering interpretation of small-scale features and comparison of reimaged regions for change detection…
The evolution of co-orbiting material in the orbit of 2201 Oljato from 1980 to 2012 as deduced from Pioneer Venus Orbiter and Venus Express magnetic records
Zhang, Tielong; Russell, Christopher T.; Lai, Hairong +1 more
Asteroid 2201 Oljato passed through perihelion inside the orbit of Venus near the time of its conjunction with Venus in 1980, 1983, and 1986. During those three years, many interplanetary field enhancements (IFEs) were observed by the Pioneer Venus Orbiter (PVO) in the longitude sector where the orbit of Oljato lies inside Venus' orbit. We attribu…
A Gemini/GMOS study of the physical conditions and kinematics of the blue compact dwarf galaxy Mrk 996
Thuan, Trinh X.; Izotov, Yuri I.; Carrasco, Eleazar R. +1 more
Aims: We present an integral field spectroscopic study with the Gemini Multi-Object Spectrograph (GMOS) of the unusual blue compact dwarf (BCD) galaxy
Methods: We show through velocity and dispersion maps, emission-line intensity and ratio maps, and by a new technique of electron density limit imaging that the…
Spectral state transitions of the Ultraluminous X-ray Source IC 342 X-1
Kaaret, P.; Mushotzky, R. F.; Miller, N. +6 more
We observed the Ultraluminous X-ray Source (ULX) IC 342 X-1 simultaneously in X-ray and radio with Chandra and the JVLA to investigate previously reported unresolved radio emission coincident with the ULX. The Chandra data reveal a spectrum that is much softer than observed previously and is well modelled by a thermal accretion disc spectrum. No s…
XMM-Newton observation of the Galactic supernova remnant W51C (G49.1-0.1)
Sasaki, Manami; Heinitz, Cornelia; Warth, Gabriele +1 more
Context. The supernova remnant (SNR)
Aims: Diffuse X-ray emission from the interior of the SNR can reveal element abundances in the different emission regions and she…
The Ground-based H-, K-, and L-band Absolute Emission Spectra of HD 209458b
Zellem, Robert T.; Griffith, Caitlin A.; Swain, Mark R. +2 more
Here we explore the capabilities of NASA's 3.0 m Infrared Telescope Facility (IRTF) and SpeX spectrometer and the 5.08 m Hale telescope with the TripleSpec spectrometer with near-infrared H-, K-, and L-band measurements of HD 209458b's secondary eclipse. Our IRTF/SpeX data are the first absolute L-band spectroscopic emission measurements of any ex…
The role of ultraviolet imaging in studies of resolved and unresolved young stellar populations. M31 and M33
Bianchi, Luciana; Hodge, Paul; Williams, Benjamin +2 more
We discuss the relevance of UV data in the detection and characterization of hot massive stars and young stellar populations in galaxies. We show results from recent extensive surveys in M31 and M33 with Hubble Space Telescope (HST) multi-wavelength data including UV filters, which imaged several regions at a linear resolution (projected) of less …
IGR J17488-2338: a newly discovered giant radio galaxy
Venturi, T.; Bird, A. J.; Ubertini, P. +4 more
We present the discovery of a large-scale radio structure associated with IGR J17488-2338, a source recently discovered by INTEGRAL and optically identified as a broad-line AGN at redshift 0.24. At low frequencies, the source properties are those of an intermediate-power FR II radio galaxy with a linear size of 1.4 Mpc. This new active galaxy is t…