Search Publications
Surveying the sky with the Arcminute MicroKelvin Imager: expected constraints on galaxy cluster evolution and cosmology
Lasenby, Anthony N.; Cotter, Garret; Grainge, Keith +4 more
We discuss prospects for cluster detection via the Sunyaev-Zel'dovich (SZ) effect in a blank field survey with the interferometer array, the Arcminute MicroKelvin Imager (AMI). Clusters of galaxies selected in the SZ effect probe cosmology and structure formation with little observational bias, because the effect measures integrated gas pressure d…
A Dynamical Mass Constraint for Pre-Main-Sequence Evolutionary Tracks: The Binary NTT 045251+3016
Latham, David W.; Mazeh, Tsevi; Prato, L. +6 more
We present an astrometric-spectroscopic orbital solution for the pre-main-sequence binary NTT 045251+3016. Interferometric observations with the HST Fine Guidance Sensor No. 3 allowed stellar separations as small as 14 mas to be measured. Optical spectra provided 58 radial velocity measurements of the primary star, and near-infrared spectra provid…
Benzene on the Giant Planets
Drossart, Pierre; Bézard, Bruno; Encrenaz, Thérèse +1 more
We report the detection of benzene ( c-C 6H 6) in the upper atmospheres of Jupiter at midlatitudes and Saturn (disk average). Observations with the Short-Wavelength Spectrometer of the Infrared Space Observatory reveal emission from the Q-branch of benzene around 14.84 µm on these two planets but not on Uranus and Neptu…
Distribution and Evolution of CH4, N2, and CO Ices on Pluto's Surface: 1995 to 1998
Buie, M. W.; Grundy, W. M.
We present new near-infrared spectra of the planet Pluto obtained at Lowell Observatory on 83 nights during 1995-1998. The dense temporal sampling of our observations enables us to measure with unprecedented detail cyclical changes in the depths of methane, carbon monoxide, and nitrogen ice absorption bands, modulated by Pluto's diurnal rotation. …
Helium energetics in the high-latitude solar wind: Ulysses observations
Reisenfeld, D. B.; McComas, D. J.; Steinberg, J. T. +4 more
We present a study of the interplanetary evolution of solar wind helium (alpha particle) energetics. The analysis of Ulysses observations of the fast high-latitude solar wind concentrates on the radial evolution of the alpha-proton differential streaming vαp, the alpha temperature, and the alpha temperature anisotropy. Ulysses observati…
The M31 Globular Cluster Luminosity Function
Brodie, Jean P.; Huchra, John P.; Barmby, Pauline
We combine our compilation of photometry of M31 globular clusters and probable cluster candidates with new near-infrared photometry for 30 objects. Using these data we determine the globular cluster luminosity function (GCLF) in multiple filters for the M31 halo clusters. We find a GCLF peak and dispersion V00=16.84+/-0.11, σ…
Hydrodynamics of photoionized columns in the Eagle Nebula, M 16
Ward-Thompson, D.; Whitworth, A. P.; Williams, R. J. R.
We present hydrodynamical simulations of the formation, structure and evolution of photoionized columns, with parameters based on those observed in the Eagle Nebula. On the basis of these simulations we argue that there is no unequivocal evidence that the dense neutral clumps at heads of the columns were cores in the pre-existing molecular cloud. …
A Possible Massive Asteroid Belt around ζ Leporis
Jura, M.; Chen, C. H.
We have used the Keck I telescope to image at 11.7 and 17.9 µm the dust emission around ζ Leporis, a main-sequence A-type star at 21.5 pc from the Sun with an infrared excess. The excess is at most marginally resolved at 17.9 µm. The dust distance from the star is probably <=6 AU, although some dust may extend to 9 AU. The mass of o…
Spatial Distribution and Temporal Evolution of Coronal Bright Points
White, Stephen M.; Zhang, Jie; Kundu, Mukul R.
We present a statistical study of the spatial distribution and temporal evolution of coronal bright points (BPs) by analyzing a continuous set of observations of a quiet-Sun region of size 780'' × 780'' over a period of 55 hours. The main data set consists of observations taken by EIT (the Extreme-ultraviolet Imaging Telescope on board the SOHO sp…
Outgassing Behavior and Composition of Comet C/1999 S4 (LINEAR) During Its Disruption
Weaver, H. A.; Lis, Dariusz C.; Bockelée-Morvan, Dominique +9 more
The gas activity of comet C/1999 S4 (LINEAR) was monitored at radio wavelengths during its disruption. A runaway fragmentation of the nucleus may have begun around 18 July 2000 and proceeded until 23 July. The mass in small icy debris (<=30-centimeter radius) was comparable to the mass in the large fragments seen in optical images. The mass bud…