R. David Joseph

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Several decision algorithms were used to classify complex patterns recorded by TV cameras aboard unmanned, scientific satellites. Recognition experiments were performed with two kinds of patterns: lunar topographic features and clouds in the earth's atmosphere. Classification accuracies ranged from 53 percent to 99 percent on independent data.
Since H3+ was first spectroscopically detected on Jupiter, there has been considerable interest in using this simple molecular ion to probe conditions existing in the planet's auroral regions. Here we present a series of images of Jupiter recorded at wavelengths sensitive to emission by H3+, which reveal the spatial distribution of excited H3+ molecular(More)
To understand the nuclear stellar populations and star formation histories of the nuclei of spiral galaxies, we have obtained K-band nuclear spectra for 41 galaxies and H-band spectra for 20 galaxies in the ISO Atlas of Bright Spiral Galaxies. In the vast majority of the subsample (80%), the near-infrared spectra suggest that evolved red stars completely(More)
We examine far-infrared and submillimeter spectral energy distributions for galaxies in the Infrared Space Observatory Atlas of Bright Spiral Galaxies. For the 71 galaxies where we had complete 60 180 μm data, we fit blackbodies with λ emissivities and average temperatures of 31 K or λ emissivities and average temperatures of 22 K. Except for high(More)
We examine far-infrared and submillimeter spectral energy distributions for galaxies in the Infrared Space Observatory Atlas of Bright Spiral Galaxies. For the 71 galaxies where we had complete 60 180 μm data, we fit blackbodies with λ−1 emissivities and average temperatures of 31 K or λ−2 emissivities and average temperatures of 22 K. Except for high(More)
We present Spitzer 3.6–160 m images, Spitzer mid-infrared spectra, and JCMT SCUBA 850 m images of the Sombrero Galaxy (NGC 4594), an Sa galaxy with a 10 M low-luminosity active galactic nucleus (AGN). The brightest infrared sources in the galaxy are the nucleus and the dust ring. The spectral energy distribution of the AGN demonstrates that, while the(More)
By Steven Millery, N ick Achilleosy, Gilda E. Ballester, Thomas R. Geballe, Robert D. Joseph, Ren ¶e e Prang ¶e, Daniel Rego, Tom Stallardy, Jonathan Tennysony, Laurence M. Traftony and J. Hunter Waite J r Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK Department of Atmospheric, Oceanic and Space Sciences,(More)
A growing body of observational evidence suggests that the luminosity, photometric shape and amount of rotational or anisotropical support in elliptical galaxies may provide vital clues to how they formed. Elliptical galaxies appear to fall into two distinct categories based on these parameters: bright, boxy shaped, with little or no rotation, and less(More)
Infrared bright galactic nuclei may be powered by accretion of matter onto a black hole, a burst of new star formation, or both of these processes. To gain insight into such processes we have used integral field spectroscopy to observe a sample of galaxies with identified AGN or nuclear starbursts. We confirm the presence of a starburst in the nuclear(More)