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Hubble Space Telescope Faint Object Camera calculated point-spread functions
Hollis, J. M.; Dorband, J. E.; Lyon, R. G.
A set of observed noisy Hubble Space Telescope Faint Object Camera point-spread functions is used to recover the combined Hubble and Faint Object Camera wave-front error. The low-spatial-frequency wave-front error is parameterized in terms of a set of 32 annular Zernike polynomials. The midlevel and higher spatial frequencies are parameterized in …
Astrometry of the globular cluster 47 Tucanae and possible optical identification of X-ray sources.
Koch-Miramond, L.; Auriere, M.; Geffert, M.
Positions of stars of 47 Tuc have been derived by the use of photographic plates and CCD frames (ESO La Silla) and data from the Hubble Space Telescope (HST). The positions have been determined with respect to the PPM, which is based on the FK5 system. We have compared the positions of variable and blue stars in the core of 47 Tuc with those of th…
Astronomical Search and Laboratory Spectroscopy of the FeCO Radical
Kagi, Eriko; Kasai, Yasuko; Ungerechts, Hans +1 more
The millimeter and submillimeter spectrum of the FeCO radical in the 3Σ- ground electronic state has been observed in the laboratory. The radical was generated by a DC glow discharge in a mixture of Fe(CO)5 and argon. A total of 33 rotational transitions in the three spin sublevels with Ω = 1, 0 were observed in th…
Recurrence of Energetic Particle Flux Anisotropy as Observed by ERNE on 9 July 1996
Laitinen, T.; Vainio, R.; Valtonen, E. +3 more
A solar energetic particle event was observed on 9 July 1996, by the ERNE sensors LED and HED on board the SOHO spacecraft. The arrival of the first protons in the energy range >20 MeV took place at 09:55 UT, 43 min after the maximum in the X-ray and Hα radiation of a flare located at S10 W30. The rise phase of the particle intensities at all e…
Statistical Properties of the Big Blue Bump in Active Galactic Nuclei
Wang, J. M.; Zhou, Y. Y.; Yu, K. N. +2 more
The shape is the most important characteristic of the big blue bump (bbb). By employing the sample from Walter & Fink, and supplementing it with medium energy X-ray data, we have been successful in separating the bbb component from the nonthermal component for the soft X-ray region and thus obtaining the cutoff energy Ecut of the bi…
The Location of the Nucleus of NGC 1068 from HST Imaging Polarimetry and Absolute Astrometry
Macchetto, F. D.; Capetti, A.; Lattanzi, M. G.
We present the results of a program to obtain an accurate (better than 100 mas) astrometry of HST images of NGC 1068 and consequently a direct registration with radio images. The optical peak seen in the HST images is located at α = 02h42m40.711s, δ = -00°00'47.81 (J2000, FK5), with an error of 80 mas. The hidden nucleus, as determined by HST imag…
Absolute proper motions for the calibration of the HIPPARCOS proper motion system
Klemola, A. R.; Geffert, M.; Schmoll, J. +1 more
Absolute proper motions of 48 Hipparcos stars in nine fields distributed over the northern hemisphere are presented. The proper motions have been recently used as part of the Bonn program for the extragalactic link of the Hipparcos proper motion system. We describe methods which have led to the absolute proper motions of the major part of the Bonn…
Discovery of CI around 51 Ophiuchi.
Deleuil, M.; Ferlet, R.; Vidal-Madjar, A. +6 more
We present the discovery of cold CI in the 51 Oph environment, with a column density of N=5x10^13^cm^-2^ and temperature T=~20K. This is the first β Pic-like star other than β Pic with simultaneous detection of cold dust and gas. The CI/infrared continuum ratio and consequently the gas/dust ratio are similar to the β Pic ones. Since CI has a very …
Energetic electron beams in the duskside Jovian magnetosphere: Ulysses EPAC and HI-SCALE measurements
Krupp, N.; Woch, J.; Dougherty, M. K. +4 more
The Ulysses flyby of Jupiter in February 1992 provided the first opportunity to investigate the high southern latitudes of the dusk side magnetosphere. We combine measurements taken by the Ulysses energetic particle instruments EPAC and HI-SCALE and identify bi-directional, field-aligned electron beams in an energy range from 100-380 keV. The beam…
The Surface Brightness Fluctuations and Globular Cluster Population of NGC 4478
Ford, Holland C.; Tsvetanov, Zlatan I.; Neilsen, Eric H., Jr.
We calculate the distance to NGC 4478, a neighbor of the giant Virgo elliptical M87, using the surface brightness fluctuations method on parallel data from the HST WFPC2 camera. The exposures considered were taken through the F814W filter, which approximates the Johnson I, and through the F606W filter, which is effectively a broad V filter. We des…