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Discovery of a north-south asymmetry in Saturn's radio rotation period
Gurnett, D. A.; Persoon, A. M.; Kurth, W. S. +5 more
For many years it has been known that Saturn emits intense radio emissions at kilometer wavelengths and that this radiation is modulated by the rotation of the planet at a rate that varies by up to one percent on a time scale of years. Recent radio observations from the Cassini spacecraft have revealed the appearance of a second component, with a …
Emergence of Small-scale Magnetic Loops Through the Quiet Solar Atmosphere
Bellot Rubio, L. R.; Martínez González, M. J.
We investigate the emergence of magnetic flux in the quiet Sun at very small spatial scales, focusing on the magnetic connection between the photosphere and chromosphere. The observational data consist of spectropolarimetric measurements and filtergrams taken with the Hinode satellite and the Dutch Open Telescope. We find that a significant fracti…
The Environments of Starburst and Post-Starburst Galaxies at z = 0.4-0.8
Aragón-Salamanca, Alfonso; Milvang-Jensen, Bo; Zaritsky, Dennis +16 more
Post-starburst (E+A or k+a) spectra, characterized by their exceptionally strong Balmer lines in absorption and the lack of emission lines, belong to galaxies in which the star formation (SF) activity ended abruptly sometime during the past Gyr. We perform a spectral analysis of galaxies in clusters, groups, poor groups, and the field at z = 0.4-0…
INMS-derived composition of Titan's upper atmosphere: Analysis methods and model comparison
Mandt, Kathleen E.; Waite, J. Hunter; Magee, Brian A. +3 more
The Cassini Ion and Neutral Mass Spectrometer (INMS) has recorded full altitude profile data from 20 low-altitude Titan encounters during the nominal mission (July 2004-2008). These encounters were TA, T5, T16, T18, T19, T21, T23, T25, T26, T28, T29, T30, T32, T36, T37, T39, T40, T41, T42, and T43. In this work we present an analysis of the data o…
Observations of Starburst Galaxies With Far-Ultraviolet Spectrographic Explorer: Galactic Feedback in the Local Universe
Leitherer, C.; Calzetti, D.; Meurer, G. +6 more
We have analyzed FUSE (905-1187 Å) spectra of a sample of 16 local starburst galaxies. These galaxies cover almost three orders of magnitude in star-formation rates and over two orders of magnitude in stellar mass. Absorption features from the stars and interstellar medium are observed in all the spectra. The strongest interstellar absorption feat…
Morphological Composition of z ~ 0.4 Groups: The Site of S0 Formation
Wilman, D. J.; Mulchaey, J. S.; Balogh, M. L. +3 more
The low-redshift universe (z <~ 0.5) is not a dull place. Processes leading to the suppression of star formation and morphological transformation are prevalent: this is particularly evident in the dramatic upturn in the fraction of S0-type galaxies in clusters. However, until now, the process and environment of formation remained unidentified. …
The Infrared Spectra of Very Large Irregular Polycyclic Aromatic Hydrocarbons (PAHs): Observational Probes of Astronomical PAH Geometry, Size, and Charge
Peeters, Els; Bauschlicher, Charles W., Jr.; Allamandola, Louis J.
The mid-infrared (IR) spectra of six large, irregular polycyclic aromatic hydrocarbons (PAHs) with formulae (C84H24-C120H36) have been computed using density functional theory (DFT). Trends in the dominant band positions and intensities are compared to those of large, compact PAHs as a function of geomet…
A binary origin for `blue stragglers' in globular clusters
Sills, Alison; Knigge, Christian; Leigh, Nathan
Blue stragglers in globular clusters are abnormally massive stars that should have evolved off the stellar main sequence long ago. There are two known processes that can create these objects: direct stellar collisions and binary evolution. However, the relative importance of these processes has remained unclear. In particular, the total number of …
Methane and its isotopologues on Saturn from Cassini/CIRS observations
Fletcher, L. N.; Irwin, P. G. J.; Teanby, N. A. +2 more
High spectral resolution observations from the Cassini Composite Infrared Spectrometer [Flasar, F.M., and 44 colleagues, 2004. Space Sci. Rev. 115, 169-297] are analysed to derive new estimates for the mole fractions of CH 4, CH 3D and 13CH 4 of (4.7±0.2)×10, (3.0±0.2)×10 and (5.1±0.2)×10 respectively. T…
Hot stars observed by XMM-Newton. I. The catalog and the properties of OB stars
Nazé, Y.
Aims: Following the advent of increasingly sensitive X-ray observatories, deep observations of early-type stars became possible. However, the results for only a few objects or clusters have until now been reported and there has been no large survey comparable to that based upon the ROSAT All-Sky Survey (RASS).
Methods: A limited survey of X-ra…