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Hard X-ray observations of cosmic γ-ray sources
Coe, M. J.; Quenby, J. J.; Engel, A. R.
THE publication1, by workers using the COS B satellite, of a list of 13 discrete cosmic γ-ray sources has aroused considerable interest. Attention has mainly been focussed on attempts to identify all or some of these sources with known X-ray sources2-4, optical sources5,6, radio sources7 and HII regions<…
Evidence of a Continuous Change in the Period of Cygnus X-3
Manzo, G.; Molteni, D.; Robba, N. R.
Summary. Cygnus X-3 has been observed, in the 2-12 keV energy range, continuously from 1977 June 8.46 to 1977 July 14.79 by the ESA satellite COS-B. The basic parameters of the system have been determined. A fit of the COS-B data with the values obtained previously by ANS and Uhuru gives: Pdot=(2.83+/-0.67)10^-9 s/s The value Pdot/P0=(5.2+/-1.2) 1…
Possible X-ray counterparts of gamma-ray sources.
Maraschi, L.; Bradt, H.; Apparao, K. M. V. +5 more
The results are presented of a survey regarding the X-ray source positions which fall within the error boxes of 10 unidentified gamma-ray sources observed with the aid of the COS-B satellite. In three cases, including CG 135-1, CG 312-1, and CG 327-0, an X-ray source was found within the gamma-ray error box. However, because of the large uncertain…
Observability of gamma-ray pulsars.
Massaro, E.; Buccheri, R.; Scarsi, L. +1 more
Attention is given to the Crab (PSR 0531 plus 21) and Vela (PSR 0833 minus 45) pulsars in a study of pulsed energy release in the gamma-ray channel; with a gamma-ray/radio luminosity ratio on the order of one million. SAS 2 and COS B data are analyzed in an attempt to detect possible gamma-ray emission from other known radio pulsars. A phenomenolo…
Relative phases of radio and gamma-ray pulses from the Vela pulsar.
Hermsen, W.; Masnou, J. L.; Manchester, R. N. +7 more
Gamma-ray observations from the COS-B satellite and radio pulse-timing measurements from the Tidbinbilla Deep Space Station are used to determine accurately the relative phases of the radio (2295 MHz) and gamma-ray (above 50 MeV) pulses from the Vela pulsar. Two independent analysis procedures are employed, and both show that the peak of the radio…
IUE observations of solar system objects
Gull, T. R.; Moos, H. W.; Wilson, R. +16 more
During the scientific commissioning phase of IUE several spectra were acquired from objects residing in the Solar System. The activities focused on testing numerous parameters which would indicate the usefulness of IUE for planetary science. It seems that IUE can successfully tackle many important questions and the data analysis and interpretation…
Coincidence of compact supernova remnants with three COS-B γ-ray sources
Lamb, R. C.
POSITIONAL coincidences and a `near miss' of four small-diameter supernova remnants (SNR) with three of the 11 unidentified COS-B γ-ray sources1 are reported here. I argue that it is unlikely that all four SNR-γ-ray source associations are accidental, and that their compactness probably indicates that their ages are not greater than abo…
The Lalpha /Hbeta /Palpha ratio in the quasar PG 0026+129.
Perryman, M. A. C.; Baldwin, J. A.; Longair, M. S. +1 more
Observations of the quasar PG 0026+129 with the International Ultraviolet Explorer have determined its L-alpha intensity. In conjunction with visual and infrared observations by Puetter et al. (1978), a L-alpha/H-beta/P-alpha ratio of 6:1:1.4 is derived. The ratios differ from those found in 3C 273. The implications of these observations are discu…
IUE observations of Large Magellanic Cloud members and detection of the 2,200 Å feature
Nandy, K.; Morgan, D. H.
THE dominant feature in the UV spectra of reddened stars in our Galaxy is the broad absorption feature of interstellar origin, centred near 2,200 Å and having a halfwidth of 350 Å (ref. 1). The wavelength position of this feature and the correlation of its strength with other interstellar extinction parameters, for example, the visual colour exces…
COS-B X-ray observations of Cygnus X-3.
Manzo, G.; Molteni, D.; Robba, N. R. +2 more
The ESA COS-B satellite has observed the Cygnus region in the energy range (2-12 keV), between 1975 November 28.42 and December 24.26. The Cygnus X-3 4.8 h modulation is detected. The source was in a low state with a positive evidence for an increase in flux during the month of observation.