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Shockingly bright [OI] 63µm lines from the supernova remnants W 44 and 3C 391.
Reach, W. T.; Rho, J.
The brightness of the [OI] 63µm line was measured for the supernova remnants W44 and 3C391 with the ISO Long-Wavelength Spectrometer. Bright lines, ~0.3-1.4x10^-3^erg/cm^2^/sr, were detected in the 20 positions observed toward both remnants. The lines are brightest at the edges of the remnants, but they are also bright towards the remnant in…
HST star counts at high galactic latitudes
Gilmore, Gerard; Elson, Rebecca A. W.; Santiago, Basilio X.
We use star counts from 17 deep fields imaged with the Wide Field Camera 2 (WFC-2) as part of the HST Medium Deep Survey key project in order to constrain the amount of dark matter in the Galaxy that can be in the form of low-mass main-sequence stars or white dwarfs. Based on the number of red stars found in our fields, we exclude the possibility …
Hubble Space Telescope Observations of Planetary Nebulae in the Magellanic Clouds. IV. [O iii] Images and Evolutionary Ages
Ford, H. C.; Harrington, J. P.; Wood, P. R. +6 more
The Planetary Camera of the Hubble Space Telescope has been used to obtain images in the [O III] λ5007 line for a sample of 15 planetary nebulae in the Magellanic Clouds chosen to eliminate any selection bias in either excitation class or in flux [for log F(Hβ) > -13.7 ergs cm^-2^ s^-1^]. These images are used to derive the physical dimensions,…
Searching for VIMs: an astrometric method to detect the binary nature of double stars with a variable component
Wielen, R.
The photo-center of a close double star in which one component has a variable luminosity moves on the sky in the same rhythm as the total luminosity of the system varies in time. This provides an astrometric method to detect the binary nature of the system if more direct methods fail. We propose to call such systems `variability-induced movers', o…
Star formation history of the POST starburst galaxy NGC 1569.
Bomans, D. J.; Vallenari, A.
We discuss the star formation history in the post-starburst galaxy NGC 1569 using colour-magnitude diagrams derived from HST WPFC images in the F555W and F785LP filters. This galaxy has experienced a global burst of star formation from 1x10^8^yr to about 4Myr ago. Evidence has been found of older episodes of star formation from 1.5Gyr to 1.5x10^8^…
Visible and Far-Ultraviolet WFPC2 Imaging of the Nucleus of the Galaxy NGC 205
Casertano, Stefano; Ballester, Gilda E.; Grillmair, Carl +15 more
We have imaged the nucleus of NGC 205 through the F555W and F160BW filters of WFPC2 on the high-resolution planetary camera (PC). The nucleus consists of a resolved cluster of stars extending 7" x 6". The projected radial distribution of surface brightness can be fitted by a Hubble law with a small core of FWHM 214 x 190 mas (0.74 x 0.66 pc). We f…
AO 0235 + 164 and Surrounding Field: Surprising HST Results
Cohen, Ross D.; Burbidge, E. M.; Lyons, R. W. +2 more
Results obtained with the Hubble Space Telescope on the highly variable radio, x-ray, and γ-ray emitting QSO (or BL Lac object) AO 0235+164 are presented and analyzed. WFPC2 images were obtained in 1994 June, when AO 0235+164 was bright (m ~ 17), and the results are described in Sec. 3. After subtraction of the PSF of the QSO, hereafter called AO …
Mars ozone measurements near the 1995 aphelion: Hubble space telescope ultraviolet spectroscopy with the faint object spectrograph
Wolff, Michael J.; Clancy, R. Todd; James, Philip B. +4 more
Ultraviolet (225-330 nm) spectral scans of Mars were obtained with the Hubble space telescope (HST) faint object spectrograph (FOS) in February of 1995. These spectra yield ozone column abundances, cloud opacities (0.2-0.4 at low latitudes), and polar seasonal ice albedos from southern midlatitudes to northern high latitudes on Mars. At the time o…
Hubble Space Telescope Imaging of Dust Lanes and Cometary Structures in the Inner Disk of the Cartwheel Ring Galaxy
Lucas, Ray A.; Struck, Curtis; Appleton, Philip N. +1 more
We have obtained high-resolution B and I-band Hubble Space Telescope (HST) images of the Cartwheel ring galaxy which provide unprecedented views of the structure and color of the two rings and spokes. Here, we focus on the imaging results for the central regions of the Cartwheel, its inner ring and spokes. Prior to these observations there was sur…
Perpendicular transport in shock acceleration
Giacalone, J.; Jokipii, J. R.
We consider the foundations of charged-particle acceleration at collisionless shocks in which the average magnetic field is perpendicular to the shock-normal direction. Our shock model, which is a numerical integration of the trajectories of an ensemble of test particles in specified shock fields, includes an isotropic and homogeneous, Kolmogorov-…