Search Publications
Anisotropy in the Hubble constant as observed in the HST extragalactic distance scale key project results
McClure, M. L.; Dyer, C. C.
Based on general relativity, it can be argued that deviations from a uniform Hubble flow should be thought of as variations in the Universe's expansion velocity field, rather than being thought of as peculiar velocities with respect to a uniformly expanding space. The aim of this paper is to use the observed motions of galaxies to map out variatio…
The molecular and dusty composition of Betelgeuse's inner circumstellar environment
Nguyen, Q. N.; Lopez, B.; Leinert, Ch. +6 more
Context: The study of the atmosphere of red supergiant stars in general and of
Aims: A molecular shell, the MOLsphere (Tsuji 2000a, ApJ, 538, 80…
Observations of O I and Ca II Emission Lines in Quasars: Implications for the Site of Fe II Line Emission
Kawara, K.; Oyabu, S.; Tsuzuki, Y. +1 more
We present results of the near-infrared (IR) spectroscopy of six quasars whose redshifts range from 0.158 to 1.084. Combined with the satellite ultraviolet data, the relative line strengths of O I λ1304, O I λ8446, O I λ11287, and the near-IR Ca II triplet are given. In addition, the corresponding O I line strengths measured in normal Seyfert 1s a…
Titan's corona: The contribution of exothermic chemistry
Johnson, R. E.; Waite, J. H.; Cravens, T. E. +4 more
The contribution of exothermic ion and neutral chemistry to Titan's corona is studied. The production rates for fast neutrals N 2, CH 4, H, H 2, 3CH 2, CH 3, C 2H 4, C 2H 5, C 2H 6, N( 4S), NH, and HCN are …
How Does Large Flaring Activity from the Same Active Region Produce Oppositely Directed Magnetic Clouds?
Harra, Louise K.; Wang, Jingxiu; van Driel-Gesztelyi, Lidia +7 more
We describe the interplanetary coronal mass ejections (ICMEs) that occurred as a result of a series of solar flares and eruptions from 4 to 8 November 2004. Two ICMEs/magnetic clouds occurring from these events had opposite magnetic orientations. This was despite the fact that the major flares related to these events occurred within the same activ…
Discoveries of Diffuse Iron Line Sources from the Sgr B Region
Maeda, Yoshitomo; Koyama, Katsuji; Matsumoto, Hironori +8 more
The radio complex Sgr B region was observed with the X-ray Imaging Spectrometer (XIS) on board Suzaku. This region exhibits diffuse iron lines at 6.4, 6.7, and 6.9keV, which are Kα lines of Fe I (neutral iron), Fe XXV (He-like iron), and Fe XXVI (H-like iron), respectively. The high energy resolving power of the XIS provided separate maps of the K…
Remnant of a ``Wet'' Merger: NGC 34 and Its Young Massive Clusters, Young Stellar Disk, and Strong Gaseous Outflow
Seitzer, Patrick; Schweizer, François
This paper presents new images and spectroscopic observations of NGC 34 (Mrk 938) obtained with the du Pont 2.5 m and Baade 6.5 m telescopes at Las Campanas, plus photometry of an archival V image obtained with Hubble Space Telescope. This MV=-21.6 galaxy has often been classified as a Seyfert 2, yet recently published infrared spectra …
The spatial morphology of Europa's near-surface O 2 atmosphere
Johnson, R. E.; Cooper, J. F.; McGrath, M. A. +2 more
Results from a three-dimensional ballistic model of Europa's O 2 atmosphere are presented. Hubble Space Telescope (HST) ultraviolet observations show spatially non-uniform O 2 airglow from Europa. One explanation for this is that the O 2 atmosphere is spatially non-uniform. We show that non-uniform ejection of O
Density and Magnetic Field Signatures of Interplanetary 1/f Noise
Romoli, M.; Bemporad, A.; Poletto, G. +4 more
We investigate the occurrence of 1/f noise in the interplanetary density and the magnetic field at varying heliocentric latitudes. The characteristic spectral amplitudes can be found in Ulysses density and magnetic data in the expected frequency ranges at all available latitudes, ranging from the ecliptic plane to more than 80°. Average spectra in…
Sesame - An Experiment of the Rosetta Lander Philae: Objectives and General Design
Schmidt, W.; Fischer, H. -H.; Seidensticker, K. J. +9 more
SESAME is an instrument complex built in international co-operation and carried by the Rosetta lander Philae intended to land on comet 67P/Churyumov-Gerasimenko in 2014. The main goals of this instrument suite are to measure mechanical and electrical properties of the cometary surface and the shallow subsurface as well as of the particles emitted …