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Galactic gamma — ray sources in the 40-50 MeV range
Li, Ti-Pei; Wu, Mei
A gamma-ray map of the Galaxy in 40-50 MeV reveals, besides the three sources known at higher energies, four additional sources with intensities comparable to that of the Crab.
The orbit of lambda Virginis and other matters
Stickland, D. J.
UVBY photometry of HIPPARCOS stars.
Oblak, E.
Photoelectric data in the uvby system have been obtained for 367 southern stars of the Hipparcos Input Catalogue. Most of the stars are F and G main sequence and fall in the magnitude range V = 9 to 10.
EXOSAT observations of the iron line in CEN X-3
Fabian, A. C.; Tennant, A. F.; Takalo, L. O.
Properties of the iron line in Cen X-3 have been studied, using the gas scintillation proportional counter onboard EXOSAT. The iron line energy is seen to be constant (kT = 6.59 +/- 0.06 keV) over orbital and pulse periods. On the other hand the iron line intensity is seen to vary with both periods. The pulse period variations are sinusoidal, but …
PSR 1820-11: a binary gamma-ray pulsar.
Li, Ti-Pei; Wu, Mei
Significant pulsation structure in the phase distribution of 50 - 6000 MeV gamma-rays from the direction of the binary radio pulsar PSR 1820-11 in the COS-B data was obtained by the folding algorithm. Besides period searches, a spatial analysis was performed and a clear point-like image at the pulsar's position for gamma-rays above 50 MeV was obta…
Astronomy with EXOSAT
White, N. E.
The European Space Agency's X-ray observatory EXOSAT was operational from May 1983 to April 1986 and in that time made 1780 observations of a wide variety of objects including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs, X-ray binaries, clusters of galaxies and supernova remnants. The 90hr high earth orbit allowed …
A catalogue of QSOs and link stars for the HST link of the HIPPARCOS reference frame.
White, G. L.; Hemenway, P. D.; Argue, A. N. +6 more
A list of bright (less than 17 mag) southern QSOs and bright (less than 11 mag) stars that may be suitable for the Hubble Space Telescope link between the Hipparcos astrometric reference frame and the VLBI extragalactic frame is presented. The QSOs have been selected from various lists of radio objects and identifications. The stars have been sele…
Pulsed gamma-rays from PSR 1951 + 32
Li, Ti-Pei; Wu, Mei; Ma, Yu-Qian +1 more
In a previous paper [1] we obtained statistically significant evidence for a 39-ms period in the COS-B data of 30-5000 MeV gamma rays in the direction of PSR 1951 + 32. Most of the gamma photons from PSR 1951 + 32 are pulsed and concentrated in a narrow interval of phase. We have examined the partical distribution of gamma ray intensity in the reg…
Ultraviolet Flux Variation of Epsilon Aurigae
Kang, Young Woon
The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 Å to 3050 Å. The UV light curves show two brightenings …
HD 51956: A Supergiant in an Interacting Binary
Parsons, Sidney B.; Ake, Thomas B.
IUE ultraviolet spectral observations reveal that the F supergiant HD 51956 contains a hot companion star partially obscured by warm plasma. Variable absorption features are analogous to those in the strongly interacting system HD 207739. The F type component is apparently transferring matter to a subluminous B type star which originally was the p…