Search Publications
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…
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…
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.
The UV-spectrum of the extreme helium stars BD +10 2179 and BD -9 4395.
Schönberner, D.; Hunger, K.
Summary 0 0 UV-Spectrcgrams of BD+1O 2179 and BD-9 4395 have been obtained with the lUE-satellite, in the low resolution mode (full half width N 5 ). No emission features are seen. Quantitative (fine) analyses of 3 (blended) absorption lines based on model atmospheres as derived from the visual spectrum confirm earlier results. The carbon abundanc…
X-ray observations of the variability of Cygnus X-1 in the high state.
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 November 28 and December 24, 1975. The Cygnus X-1 X-ray light curve for this period, during which the source appears to be in the high state, is reported; a search for a possible attenuation of the X-ray emission at the superior conjunction brings to the c…
COS-B observations of pulsed gamma -ray emission from PSR 0531+21 and PSR 0833-45.
Bignami, G. F.; Hermsen, W.; Masnou, J. L. +11 more
Summary. CO S-B has performed detailed measurements of the high-energy y-ray emission from the Crab and Vela pulsars. The two pulsars exhibit very similar y-ray light curves, both with narrow peaks of roughly equal intensity separated by 0.42+0.03 of the period. The fractions of the y-rays of energy >50 MeV which are pulsed have 2a lower limit …
Search for gamma-ray emission with a 4.8 h periodicity from Cygnus X-3.
Hermsen, W.; Bennett, K.; Mayer-Hasselwander, H. A. +3 more
Summary. The ESA CO S-B satellite has investigated the high energy gamma-ray emission from the Cygnus region of the galaxy during November to December 1975. From the counts observed to originate within the vicinity of Cygnus X-3 a histogram is derived using the 4.8 hour period observed at X-ray and infra-red wavelengths. The phase analysis reveals…
Increase in the pulsational period of 3U 0900-40.
Molteni, D.; Kanbach, G.; Mayer-Hasselwander, H. A. +4 more
The binary X-ray source 3U0900-40 has been observed with the X-ray detector on board the COS-B satellite between 1975 November 8.4 and 28.1 in the energy range 2-12 keV. Previously observed 283 s pulsations have been detected and were used to determine the binary orbital elements of the system. It is found that the pulsational period for November …
COS-B observations of localised high-energy gamma-ray emission from the anticentre region of the galactic disc.
Bignami, G. F.; Hermsen, W.; Bennett, K. +10 more
Summary. COS-B has observed sources of high-energy gamma rays in the anticentre region of the galactic disc. Only one of these (the Crab) can be positively identified with a source of radiation at other wavelengths. One of the other three (at 111 = 1960, b11 = +40) has been previously observed by SAS-2, but the others (at 111 = 1770, b11 = 70 and …
COS-B observations of X-ray emission from Cir X-1.
Maccagni, D.; Bignami, G. F.; della Ventura, A. +1 more
Summary The X-ray detector monitor on board the ESA satellite COS-E has observed the region of Cir X-1 (3U 1516-56), during 1976 February 24 through March 24. Two peaks of enhanced X-ray emission are clearly visible and confirm the periodic behavior of this source, as reported by Kaluziensky et al. (1976). The between the two adjacent maxima is 16…