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Seyfert Galaxy Ultraviolet Emission-Line Intensities and Variability: A Self-consistent Photoionization Analysis Applied to Broad-Line--emitting Gas in NGC 3783
Koratkar, Anuradha P.; MacAlpine, Gordon M.
Both strong and weak ultraviolet emission lines in SeYfert 1 galaxies have been accurately measured from reextracted short-wavelength camera data in the IUE satellite data archives. Line ratios, equivalent widths, and trends as functions of continuum variability were used to constrain numerical modeling parameters in detailed photoionization analy…
The Ultraviolet Spectrum of HH 24A and its Relation to Optical Spectra
Noriega-Crespo, A.; Brugel, E. W.; Boehm, K. H. +1 more
We have studied the spectrum of the brightest part (HH 24A) of the complex Herbig-Haro object HH 24 in the short wavelength (1300 A The ultraviolet spectrum is definitely detected in three observations with exposure times of 560 to 680 min. It is, however, sufficiently faint that corrections for the IUE "artifact spectrum" (as described by Crensha…
Almucantar deformations in the method of equal altitudes
Pesek, I.
Systematic deformations of apparent almucantar of order of 0.1 arcsec were derived from two five-year series of circumzenithal observations by the method of equal altitudes. Simple method is presented which makes it possible to check for almucantar deformation all data obtained by the method of equal altitudes, selected for rereducing earth rotati…
Geminga pulsar in COS-B and HEAO-B observations.
Sun, X.; Ma, Y.; Li, T. +4 more
The Billion Amp Current that Flows Round Jupiter
Henbest, N.
UV observations of LB 3193 and LB 3116 : two hot post-AGB object in the galactic halo ?
Lamers, H. J. G. L. M.; Quin, D. A.
LB 3193 and LB 3116 have visual spectra indicating that they are B2-B5 supergiants situated at large distances from the galactic plane. UV observations of both objects show that they are metal deficient stars, whose energy distributions match their adopted atmospheric parameters. Further investigation of mass luminosity relationships of various ev…
HST observations of the inner coma of Comet Levy 1990c.
Pasian, F.; Fulle, M.; Benvenuti, P.
Comet Levy 1990c was observed by the Hubble Space Telescope on 27 September 1990, thus allowing to test data reduction procedures which will allow to model the nucleus of future targets of cometary space missions. The authors observe faint hemispherical shells expanding in the coma, which is structured as a sunward fan deflected by solar radiation…
EXOSAT measurement of the spectrum of Markarian 382.
Singh, K. P.; Rao, A. R.; Vahia, M. N.
The 0.1-10 keV X-ray spectrum of a Seyfert galaxy known as Markarian 382 (Mkn 382) is presented based on observations with the EXOSAT. The energy index (α) for the power-law X-ray continuum of Mkn 382 is measured to be 1.2^+0.16^_0.14_ which is higher than the canonical value found for the Seyfert galaxies. There is no evidence for intrinsic absor…
The treatment of HIPPARCOS observations of some peculiar double stars - Anomalous cases
Pannunzio, R.; Lattanzi, M. G.; Morbidelli, R. +2 more
We present an investigation on a few different types of double stars which, when observed by the Hipparcos satellite, will probably produce anomalous signals. Specifically, for these objects the automatic data reduction chain set up by the FAST Consortium will usually give inconsistent results. Thus, some new mathematical models have been consider…
X-Ray Continuum with an Iron Emission Line from the Radio-Quiet Quasar PHL 909
Ghosh, K. K.; Soundararajaperumal, S.
Results of the spectral analysis of the X-ray (0.1 - 10 keV) spectrum of the radio-quiet quasar, PHL 909, are presented. A spectrum of this quasar which was observed on 1984/349, was obtained from the EXOSAT archives. Different models were used to fit the ME and LE+ME data. Fit parameters to the ME data show a steep spectral index for this quasar …